I suddenly find myself owning 1970 4-cylinder 2.4 with Web hot street Cam idles nicely and pulls hard at WOT. Part throttle response is not great, often with carbs coughing and even backfiring on trailing throttle. My use is mostly street, so I'd like to get this part throttle stuff sorted.
Here's pictures of the stuff that's in there now. I guess that's the infamous Bosch 009 with no vacuum advance and a PerTronix 1847A. The carbs are Dellorto DRLA 45s with short velocity stacks and these tall foam things that don't seal against the air cleaner housings. I'm willing to learn about the carbs but I don't have much confidence in the 009 for running nicely on the street. Please correct me if I'm wrong about any of this stuff.
Also from other threads I gather that switching to EFI such as MicroSquirt would cost $5K or so ... though I'm not ruling this out completely. Correct me if I'm wrong about that.
Is this kind of linkage OK?
Here's the idle you may have seen in another post:
Any help you can provide is appreciated!
--Michael in Seattle
I don’t think a micro squirt conversion runs that much, but I’d look for ignition control if you were switching over. The Bosch 009 doesn’t work that well from what I’ve heard, but perhaps others can chime in what has worked for them.
Cheapest would be to ditch the hex bar and get a CSP linkage, then find a redtop Mallory dizzy. You could ditch the points and add a pertronix, plus get grey/grey springs from aircooled.net
Buy the CBPerformance Dellorto book and your carb problems will go away as to spitting and coughing or other carb issues
Once upon a time long, long ago in a galaxy far, far away (pre-internet) I was researching recommendations for a jetting for Weber 40 IDF's on a 2056 with a hot cam. I called several Weber suppliers, and they all recommended major upgrades to the ignition system as a starting point. This included a multi-spark box, upgraded coil and a point replacement system. I went with the Crane Hi-6 and PS-91 coil and a Pertronix and it made a major improvement in driveability.
As time went by, the internet came along and I found out the 009 distributor the Previous Owner installed was nor really suitable for Ty4 engine. The Mallory was recommended, but the original equipment Bosch would be vastly superior to the 009. Since the PO had included the original distributor with the car, I reinstalled that and again found a significant improvement in driveability.
Invest in the CB dell manual and a synchronizing tool. Pelican (among others) has them, #PEL-TOL-STESK. Or be prepared spend $100+an hour to have someone sort the carbs out. You could buy a 123 dist for a carbed engine and have money leftover just to discover what might be amiss if subbing out the work. While the 009 will fuction, your ingnition will not be optimized.
Do those tall air filters interfere with the rain tray?
PS replace the fuel line clamps with the shouldered variety as opposed to the slotted type.
I found what might be the linkage Mark's recommending?
It says for IDFs... also suitable for DRLAs?
But I'm guessing that there's not much point in tinkering with the carbs until a more appropriate distributor is installed -- is that correct?
Sorry for a possibly dumb question: I'm actually not 100.0% sure that's a Bosch 009. I assumed that it was because I googled the number on the rotor "1234332215 .08" and it was associated with the 009. Do I definitely have a 009 now?
Another view showing the PerTronix 1847A position sensor. I guess I'd need to move that oil pressure sender if I installed a Mallory?
I'm reading about the Mallory distributor now. I found some old posts where Jake Raby is recommending the non-vacuum advance models because those mechanisms are hard to tune and unreliable. So that's interesting.
A previous owner installed the PerTronix Flame Thrower coil in 2010 along with the breakerless ignition.
The previous owner provided Bob Tomlinson's 1995 "The Dellorto Superformance" book.
The foam things don't look like they're sealing well. I haven't found air filters that would fit online yet. I'm curious why the current air cleaners are so much taller than the velocity stacks... maybe someone was thinking about top end only?
The Mallory distributor body is rather large. Dimpling of the pass side engine tin is required. As I understand the situation, sourcing new modules for the mallorys is difficult.
In your carb pic the vacuum advance port isn't capped off ??
If you are infact running a 09 it will need to capped off,check the other side carb also ,you may or may not have the same there.
Do you know the spec's of the carbs ?? ,been said many times but they are still large carbs for even a 2.4 if not setup right...that will leave a very soggy mid range if not right.
If your carbs are close to being dialed in you could try a vacuum advance dizzy such as the SVDA or 034 (?) Bosch type if you have vacuum ports on both carbs ,larger carbs and a hot street cam will most like see the 09 being even less desirable.
Are you running the right fuel pressure ?,is your fuel from a regulated source or direct from a LP pump ?.
Someone like John Walker will most likely need to see the engine fully tuned (plugs ,leads,timing and valve clearances ) before he will attempt tuning the carbs ,that's the order its done in.
I have a 2056 with Dellorto 40's. My car came with a 050 distributor which is supposed to be better suited to a 914 that the 009. I played around with the 050 trying to get is set up to work right in my car.... installed a Pertronix and a different coil. Tried running a CDI box. Had a flat spot just off of idle that I couldn't ever get rid of. Bought a $75 used dual point Mallory and converted it to a Pertronix II. The Mallory is way superior to the Bosch 050. The bushing/bearings are larger, the distance between the plug wires is further apart and work better and aren't as prone to spark scatter. The advance mechanism is easily user adjustable. I did not have to modify the tin or the oil sender in any way. The Mallory is the way to go if you ask me it made a huge drive-ability difference.
From my perspective you can't really pay some one to set up Dellortos for you because of the trial and error involved. You have to learn how they work and how to adjust them. I rebuilt mine and change the vents size & jet size and got them working really well. Once they are set up they don't require much in the way of adjustment. Make sure the cross-bar linkage is set up properly and the carbs are both opening at the same rate.
I assumed when you test drove the car it was running strong
But you have to remember a big 4 is not going to run like a
Its a carbed , 91 octane , with headers brute . Abrasive and snorting burbbling monster
So minor adjustments aside it should run more like a race /track car then a street or cruiser
My 2.3 has webbers it runs smooth at all
Rpm but everything was dialed in at a shop
Its close to perfect
Mine has a black cap... I bought a second one as a spare and it also has a black cap. I think the black and red caps are interchangeable and the red came on the newer models.
My carb experience has been with Webers but your symptoms to me indicate what in my case were clogged idle jets. Also possibly an intake leak. I use the Petronix Flamethrower distributor and have had good service from it for 5 years now. The body of this Petronix is also very wide and took some tweeking of the cooling tin to install.
Well ...I know I'm correct.
Black the can (body) is taller, cap is shorter and clips sit lower on the cap. The caps centers on a notch on the can.
I believe all the black tops must be oiled with a pin oiler.
Most red tops have an oil hole machined (auto oiling) near the drive gear, the lip of the cap fits over the can like a stock bosch dizzy cap and centers on a pin on the outside lip of the can. The notch is on the cap.
Both styles have different rotors, in fact IIRC there's about 5-6 different rotor styles.
I've had many of each style in my hands over the years.
Vacuum advance doesn't play well with dual carbs, as they have poor vacuum. If you add a hotter cam Vac becomes even worse.
I didn't realize that dual carbs don't produce a good vacuum signal but it makes sense. I didn't find a port on the DRLA's with a vacuum signal and I didn't want to drill them.
I have a cross bar linkage because it came with the car and it was at one time all that was available. It's probably harder to set up but once it's set it works fine. Just make sure that both sides open at the same rate.
The jets are marked ..... easy to enough to read. You can pull a venturi with out having to remove the carb by just pulling the top off the carb. They have a cone shaped set screw on the end of the barrel. The venturi are marked. I am running 34's you made need something bigger. If you take the top off a carb be careful not to damage the gasket or inadvertently bend the float tangs and change the fuel level.
Do a search here I am sure there are a bunch of threads concerning dialing in carbs. This one is pretty useful: http://www.aircooled.net/synchronize-dual-vw-carburetors-103/
Sorry but just want to make sure all the facts are there
You are running premium gasoline ? Correct
Sounds like you have a lot more experience with these cars then i do
But ive always heard dellorto s are supposed to be the
Technicallly superior carb because of their
Behavior when not at wot
Like a partial circuit or something.
So they are smoother , more street oriented then
Thats not necessarily the story here but then again
Did the guy who built it use dellorto for a reason
Or thats just what was available
As y'all advised, I bought an air-flow meter. I was able to measure what was happening at idle. At the time the engine was warm and idling fast, around 1200 RPM. It often idles lower than that.
With only one meter, I didn't see a way to compare the behavior at speeds other than idle. Is there some trick to this that I don't know? If not I guess I'll buy another meter(s) to watch more than one throat at a time while revving the engine. Sometimes when I'm driving, I'm wondering whether it's running right at slight throttle, just off of idle.
At idle I noticed slightly less flow from cylinder #3. It reads 5 while the others read almost 6. Is this a significant difference?
Cylinder #4 below:
Cylinder #3 below:
Idling fast at the moment:
Cylinder #2 below:
Cylinder #1 below:
I also got more legitimate looking air filters from CB Performance to replace the foam things the previous owner had for some reason. But I still have the long studs, so removing the air filters is more of a hassle than it should be. I don't know if it's easy to find shorter studs. I'm tempted to buy taller filters just to reduce the hassle.
I always disconnect at least on carb from the linkage. You don't need 2 meters just move it from throat to throat. I set my idle at like 900....1200 is too fast. You adjust the idle screws on each carb to get the flow to match. Slow the idle on the carb that is flowing the most air. When you first start playing with them it can be frustrating but one you get the hang of it it's really pretty easy. Then set the mixture screws.
Get the timing set up where you want it before you set the carbs. If you change the timing after you adjust the carbs it will change your idle speed.
No reason to by new studs just measure them and then cut them with a hack saw. The studs are an american thread size I believe. I was able to buy a set at the local ace hardware.
If you cut them with a hack saw remove them first.
The studs are #10 X 32 thread size.
I fought with mine when I first set them up. Make sure that the linkage on both cars are symmetrical. The rods that attach from the linkage to the arm on the carb should be the same angle... otherwise one carb is going to open at a different rate than the other. You can operate the linkage with the car running manually to check the flow at higher rpm. I try to hold it at 2500 rpm and compare one carb to the other to ensure the linkage is working correctly. Set the idle with one side disconnected and then reconnect and make sure that there is no change in rpm when you reconnect... adjust the rod if you have to so that the rpm doesn't change.
I noticed in your photos that there is a spring on your throttle cable. I have never seen that before. My carbs have springs built in to the throttle shaft. That extra spring may be causing your idle to change with engine temperature. I have my cable adjusted so that there is a little bit of slack in it so that as the engine heats up it doesn't pull on the cable and change the idle. You might try eliminating the spring on the cable.
Maybe this will help you:
He doesn't go into making sure the linkage is set up correctly or how to check it at rpm. It is a simple explanation of how to set the idle.
Yeh that throttle cable spring is intresting
And id say idle speed varies a little bit
But 1200 is on the high side
Once again ive heard dellortos
Are the smoothest as far as partial throttle is concerned
Back the pass side idle speed adj screw off of the stop. Does the engine stumble or a marked change in the idle? Using the driver's side, pass side off stop, turn the idle up to 1.3k. Now measure the flow on the front venturi of both carbs. You want a stable needle on the flow measuring tool. Now you can control/increase the idle speed with ONLY the driver's side ISAS. Matched at idle means nothing if the flow measurements change when the linkage is working. You don't want to be dropping a c-note + per hour for a linkage problem or needs carbs rebuilt "diagnosis".
When idling, filter tops off, and you glance down the carbs do you note any fuel dribbling?
You don't need to spend $ on an additional flow measurement device.
I have a 2270 with 45 Dellortos and a Mallory Unilite distributor. I had a similar experience as you have with a off idle stumble. When taking off slow from a stop it would jerk around a little before taking off unless I took off fast. I played with the everything from timing, jetting, float levels, accelerator pump, clean carbs, and coils. It did get a little better but it was still there a little so I thought thats how it is coz I tried everything I thought. One time I was cleaning the carbs and noticed some of the auxiliary venturis were a little loose in the bore so I tighten them up until all the wiggle was gone. I would always try to make sure these were tight but they would loosen up. This time I notice that a couple of the set screws would not go all the in and would stop at a certain point so I retapped them. When I tighten them I wiggled them until they were tight in the bore. When I got it all together and drove most of the hesitation was gone and thought wow this is nice. I also learned that the transition from low to high circuit was lower than I thought and leaned the accelerator pump and that removed the rest of the hesitation. That's been my experience. After thinking about it I thought if the venturis were loose then maybe some air was getting between them and either delaying the high circuit or leaning it.
I hope another newbie question is appropriate. I noticed this intake manifold gasket is deformed. Is this caused by overtorquing? Will it leak?
I have not removed the carbs yet -- still afraid of messing something up.
I've never seen one like that. Neoprene? If you want to investigate just remove the 8 nuts, cable and fuel supply line. Then you can lift both carbs at the same time preserving the current settings. Nyloc nuts? That's a new one too.
Holy cr#p never seen base caskets like that,WAY too thick if they are overtightened you could bend the carb bases...seen it before ,thick cork gaskets can do the same.
The correct gaskets are only 1mm thick and usually high temp material,I have an Italian Dellorto kit in front of me now.
The OP needs to go right through this whole setup and start again from scratch,every problem or potential issue needs to be sorted before trying to tune them afterall.
One thing at a time.
Any VW/bug shop in the Seattle area will have the proper gasket.
IIRC those are CB performance gaskets, I think they called them "dellorto doctor".
Dellorto's have a weird notch cast in the throat that makes an annoying whistle, the gaskets have a molded part that stick up into the notch to stop the whistle. I believe they are a hard plastic.
This is all going from memory from back in the 90's.
My carbs had some thick gaskets somewhat similar to that. They have a built in raised portion that fills in a boss/void in the bottom of the body of the carb. I used them till I wore them out...I was never able to find a source for them. The raise portion keeps the carbs from whistling or chirping. If they aren't leaking I would leave them alone. In fact if you aren't planning to rebuild the carbs I wouldn't remove them.
Just googled I was thinking dellorto "Jet Doctor" which was made to solve a dell jet issue,
Below is the gaskets I'm talking about, MarkV here's where you can get them and many other dell parts.
Link to the dell parts
Nice that they are still available although mine doesn't whistle or chirp without them. I suppose you could fill the the void with something besides a gasket if you had the chirp.
Problem is with what?
If it ever did fail you'd have a nice chunk of whatever go down your intake.
Nyloc nuts are probably not what I would use but no big deal. The problem with them is they may want to unscrew the stud from the manifold when you go to loosen them. I would just snug them evenly.
Looks like you have the dellorto upgrade kit because you have the longer idle jet holders. Look inside and see if you have a fuel rail that goes across. These upgrade kits are good. I would start by removing the idle jets and the pump jets that are on the sides of the carbs and blowing them out with air. When reinstalling them, make sure the notch on the pump jet is pointing up. You'll need patience when reinstalling them so take your time. Then drive it and see how it responds. If that doesnt work, I would suspect the rubber gaskets which were used to stop the dellorto whistle
I don't get how it could bow down that much.
So the gaskets weren't leaking (at least at idle). It does seem that the right side of the engine is pulling harder than the left off of idle. So I think I need to adjust the linkage.
Check to make sure the linkage arms both come off the stops at the same time. You can do this by placing your finger where it comes of the stop on one side and looking at the other side. Also the linkage arm rods should have the same angle from the linkage to the carb base area, if not they will open at different rates. Also it sounds like it running on three cylinders, check the idle jets and pump jets. Try lowering the idle half a turn at a time on each carb. I think what might have happened is that one linkage arm came loose and moved over and is causing the high idle by jamming the linkage arm. Both throttle arms have to be resting on the stops at idle
I does sound like it running on three cylinders. I would clean the idle jets. Those brass tubes that are sticking up with the slot head next to the carb throats are the idle jet holders. You unscrew them and pull the jet off the end of the holder and spray carb cleaner through them. You can hod the jet up to the light to see if it the orifice is clear. They are small so be careful not to lose one or drop it down the carb throat. I usually do it one at a time.
As for the angle of the linkage the actuator arm has a set screw that tightens into the hex bar. You can move the actuator from left to right so that they both have the same angle and are parallel. The swivel rod is also adjustable so that they both have the same slack. You want to make sure one of them isn't opening faster than the other.
The linkage is not metric. It set nut takes a 3/8" wrench but I use a small crescent wrench so that I can adjust it small enough to adjust the rod.
If you look at my photo you can see that my actuator arms are all the way at the end of the hex bar. Yours look like they are more inboard which doesn't really mater as long as they are both the same.
Perhaps the allen screws backed off and the linkage arms moved? Also the linkage bar that goes across shouldn't move from carb to carb. It should have the smallest amount of play so it doesn't bind and it should not move up or down. At this point, I would either buy a new CB linkage or the CSP linkage and have a VW shop install it.
It looks like the hex bar is adjusted all to way to one side for some reason. The pivots for the hex bar that hold tension on the springs are adjustable. In one of the photos the pivot is almost all the way inside the hex bar and in the other photo the pivot is adjusted most of the way out.
The angles you have highlighted in green are pretty much fixed. The angle from side to side is the angle that you want to make sure is symmetrical. If one of those bars has a different angle than the other the carbs aren't going to open in unison. I have a cheap magnetic base angle finder/gauge from Harbor Freight that I used when I set my carbs up that helped me get it right.
Different intake manifolds created the width difference. Your manifolds have a sharper turn into the head, whereas the cb manifolds have a gentler turn. The cb manifolds are also taller. I use those dell carb gaskets as a soft mount of sorts, though i cut them apart so they fit flat. The cb crossbar for type4/914 is longer, for type1 shorter. The ball ends supporting the crossbar look cobbled together which led me to think that's a type1 length bar made to work. Check the part numbers on your air cleaner base plates and see if they are for type1 or 4 with cb. Good luck, have fun.
I could be wrong but I think he has all of the correct parts they just need to be setup correctly. unless I am missing something in the photos I think I would start by centering the hex bar in the left and right pivots.... if he is missing an inner spring find a replacement. After the hex bar is centered then move the arms so that they are symmetrical and then adjust the length of the drop rods. Last move the accelerator arm so that it lines up with the cable and maybe remove that extra spring that is on the outside of the accelerator cable.
There are two angles to check. There is a front to back angle that is pretty fixed and there is a left to right angle. You have to set the left to right before you set the front to back. If you have the left to right set the same on both sides the front to back cant be off although you may have to adjust the length of the rods.
Take to spring you have to the hardware store and see if you can find something close that will work. My local Ace Hardware has a plastic bin with multiple assorted springs.
Here is a photo from directly above. See how there is an angle from the pivot arm to the carb? The pivot on the pivot arm is closer to the center of the photo than the pivot on the carb. One is not directly over the other....that angle need to match on both carbs. The pivot arm is more inboard than the pivot on the carb.
The CB linkage should be spring loaded on both sides. You'll be fighting that old setup for eternity.
From what I can see in post #43 the thick intake gasket is deformed and leaking air. It looks to me like you can see the inner edge of the gasket has been squeezed out. The carbs will never sync up if you have a big intake gasket leak.
Ditch the hex cross bar and get a CSP bellcrank. I found a CSP type 4 kit at Mid-America Motorworks for $125, even if you paid another $50 it's worth it. Think of the CB cast hex bar as a linkage from a Yugo, and the CSP as from a Porsche. There's that much of a difference. https://www.csp-shop.com/en/engine/type-4-bellcrank-linkage-for-porsche-fan-system-and-ida-129-941-400ida-23951b.html
So you're saying my car is a Yugo because it has a cross bar linkage.
Both linkages do the same thing one is just easier to set up than the other.
The pictured linkage has been around. Stuff wears out. Heim joints get sloppy. Fix the gasket/nut/lockwasher issue before you do anything else.
The CSP products are higher quality, that will give you better and much easier adjustment as well as smoother throttle actuation, that's what I'm saying MarkV.
You can make a linkage from coat hanger and welding rod if you want to, it's your car, do whatever you want.
A new linkage and maybe some new carb base gaskets will certainly help.
If you cant get the linkage locally here is a link that might be closer to you:
I ordered parts from CIP and they showed up two days later and I live across the country. My mailmans feet were on fire. You just need to make sure your throttle cable will reach the CSP setup which bolts onto the case at the lowest point and closest to the trans housing
I'm trying to put the CSP Type 4 Porsche kit onto my DRLA 45s. The instructions at https://www.csp-shop.com/technik/pdf/deeng/18236.pdf are for IDFs and I made the mistake of following the step about removing the throttle return spring. This seems to have been unnecessary given the way the previous hex bar was installed.
Anyway, I'm a klutz and the spring has more tension than I expected and I'm wondering if anyone has any special trick for getting it wound up again.
There's usually only about a half turn on that.
Needle nose pliers or small set of vice-grips. Put it back together and leave everything loose and then wind up the spring and get it in place last before you tighten the nut.
I had to use more like 8 ft/lbs of torque (twice the amount in the instructions) to get the SW11 throttle control shaft nut to align with the lock tab. I hope The Maker will forgive my transgression.
UPDATE: I found this picture of "properly installed tab washer" online. I do not see how my tab washer can perform its function on the CSP throttle lever, and wondering if I should just replace it with a conventional washer.
(Or ignore this as a trivial issue and keep going with the CSP installation since it's taking longer than I expected.)
I unscrewed the pushrod (why is it called that when it actually pulls?) and attached the little ball socket to the CSP lever, using 8mm and 7mm spanners. I guess the next step is to put this left carburetor back on the engine and pull the right one.
On a set of 45s I have, that open port has a small brass tube inserted in it with a rubber(?) cap on it. Big time vacuum leak below the throttle plate on yours.
I'd look to see if I could find a brass tube to fit, maybe off of an old carb.
If you have a vac advance dizzy that's the first place I'd try to pull vac from. I'd also tee it with the one from the other carb.
A thin 8mm open end wrench is the thing to snap off the ball ends. You want to take both long rods and adjust them so they are the exact same length. There are two different ball socket ends, left and right threads. It's made like that so you can turn them when installed. When you get them installed,put a sharpie mark on the top of both pull rods so you can count the turns if you have to adjust, remember you have to turn them both the same number of turns.
As long as you've got a tab bent up to keep the nut from backing out, you're good
For some reason the right carburetor wasn't as covered with muck like the left one was. I still tried to clean it up a little with carb cleaner, aka wife repellent. Next time I would probably buy brake cleaner instead.
The right side was way easier since I didn't make the mistake of undoing the spring.
I noticed the other (front) end of the throttle shaft had an unlocked lock tab.
So I locked it. I'm curious how often these have actually fallen off.
The kit for IDF had another feature I didn't seem to need, as far as I can tell.
Engine compartment is much tidier without the hex bar. (I'm still wondering why there's oil spewed all around the filler.)
Cork gasket under the fill Tower assembly? You can change out the carb filter bases now. No need for the ones with the cross bar pivots.
I didn't try adjusting the CSP linkage until the next day. I used both the fingertip technique I learned from you guys (touching one while looking at the other), and also tried using paper as a feeler gauge, like a zero-lash valve adjustment. From the photo you'll see I used the CSP installation instructions for paper. This was the only use I got from the instructions, as they were written for IDFs not DRLAs.
When I tested with the air-flow meters later, the left and right carb were more in sync than I had ever gotten them before. (But there were other, much worse problems I'll describe next.)
Once the linkage was dialed in, I started the car, looking forward to it running better than ever. Instead, it ran worse than ever. It wouldn't idle, and sounded like it was running on two cylinders. I was alone (without a remote starter), so couldn't get up from the driver's seat to view the engine running after starting it. The iPad was within reach from the driver's seat, so out of desperation I tried the "TUNE" button on the 123 Ignition app.
I was surprised to discover it *would* idle (though not very well) when I bumped the advance from 12º (at 1000RPM) to 20º.
BEFORE (wouldn't idle):
AFTER (would idle):
Later I found it idled even faster with the advance at 1000RPM at 40º!
I couldn't see how changing the linkage and adjusting it better than it ever had been before would cause these problems. Maybe I had messed something up when I had the carbs out, using carburetor cleaner on the jets (should I have used brake cleaner?), trying to get the muck off of the exterior, or installing the new throttle arms? Or had I altered the mixture when I closed off the vacuum advance ports that had been wide open before? Had I knocked a spark plug wire loose?
The weirdest thing was the airflow into cylinder #3. It had always been slightly less than #4 on the same carb. But now it was *very* different. I believed it wasn't just a measurement error because spraying carb cleaner into #3 had much less effect than spraying into #4. Note that #4 was perfectly in sync with #2 on the other carb.
The next morning I limped the car (with frequent bangs from the carbs and sometimes the exhaust) to a VW shop that had been recommended by a 914World member. When I showed the owner the picture of the mismatched throats he expressed his opinion the carburetor was damaged, possibly by a backfire. He also didn't think the mismatch was bad enough to explain how awfully my car was running.
We spent a couple hours fiddling with the tuning. We noticed that all four air bypass screws were open. Closing them had no effect though. Re-open the vacuum ports... no effect. Inspected all the jets. Checked the jet sizes -- they were the original ones that come with the carb. We even tried changing back to the Bosch 009 distributor. No effect. Tamper with the CSP linkage.... no effect. The engine would idle (with soft pops every few seconds), but wouldn't run at 2000RPM. At open throttle it would run faster than 2000RPM though. At higher throttle settings I noticed gasoline splashing and sputtering from the left carburetor -- the leaky one that's generally covered by muck, not the one with the mismatched airflow.
The shop owner admitted that he was stumped. I thought that he would want to open up the carburetors to see what was happening inside, but I guess he sends them to another shop for that.
He did have *another* pair of DRLA 45s, new old stock. We installed those, made a few adjustments, and the engine idled more smoothly than I had ever heard it. At this point we had worked through lunchtime into the afternoon. Once I heard that new-car idle, I had zero desire to put my old scratched, dented, leaky carburetors back on. He called his contact at CB Performance for pricing advice, and suggested he'd sell them for $750. (No, he didn't have any new Webers lying around.) It took me about half a second to decide: YES.
I'm pretty sure y'all will give me some flak for this decision. I'm 80% sure my leaky left carb and my bent right carb could have been fixed, slowly by me, or quickly by a carburetor shop. But I really feel I'm done with those old carbs. The previous owner was using those foam air filters, letting everything in around the edges. He'd left two vacuum ports and four bypass screws open. He had them mounted on deformed gaskets. In one case there was a paper gasket stuck on top of the squishy one. In my care they'd experienced at least a thousand explosions. Who knows what hell these carburetors have been through in their life?
(However, my carb problems weren't over yet! Continued next post ....)
The Road Test
VW shop owner asked me to drive around to test the new carburetors in action. At first it seemed great. It drove smoothly out of the parking lot and pulled hard when I floored it pulling onto the street. A few blocks later I noticed popping sounds and sneezes! But only in some conditions, typically cruising around 3000RPM. Not wide open. And much less often than before. Idle was still perfect. He looked really sad and confused when I told him. I suggested we call it a day.
Today (Tuesday) I wondered how to find out what was in the exhaust at cruising speed. I don't know how hard it is to run the wires for a wideband air-fuel meter, or whether I'd like a gauge that doesn't match the others. I called a local dyno shop (with a sniffer) and found out they weren't very busy. I suggested I should drive the car on the dyno because an ordinary person cannot operate my linkage and worn syncromesh. The car was backfiring even while driving onto the test stand. While setting up, a technician noticed that the left carb's main jet stack was just flopping around in its holder, not screwed in! They screwed that in properly, and I don't think I've heard a backfire since. That was the problem I'd gone there to solve.
We did some dyno tuning, as you can see here (or in the other thread I started). Air/fuel ratio was lean on the first run and OF COURSE they didn't have Dellorto jets, so I asked him to ream out the existing 165 main jets. (I see that CB Performance sells them.) They had never seen a Bluetooth tunable distributor before. We advanced the overall timing a bit from what I had, which improved the bottom end but detracted from the top end. So we backed down just the top end. I really like the 123 distributor. We didn't explore using vacuum advance to improve drivability... still think there's a lot of potential here since this style of dyno run is only optimizing for wide open throttle.
Car ran fantastically while driving home. Unfortunately it's really raining here so didn't get to play with it.
According to http://www.914world.com/bbs2/index.php?showtopic=322371, this dyno result isn't impressive and now it's time to fix the clutch.
Thanks for sharing this! I'm also in the midst of hooking up a CSP linkage on a set of old carbs, but the -30C weather has stopped progress.
I lost track of this thread and was responding to the other one. I think you did fine price wise for a new set of Dellortos. Your old ones probably just need to be rebuilt and you can recoup most of what you paid for the new ones.
You might replace all of the shifter bushings before you give up on the transmission. The input seal on the transmission could be leaking and contaminating the clutch. The previous owner should have replaced that seal and the drive seals while it was out of the car.
After reading most of the posts I didn't see mention of the Camshaft. Ask the previous owner if the original FI Cam was replaced with a Cam for Carburetor set up. I had some off the problems you mentioned with my 914 1.8 when I bought it. After an engine rebuild we replaced the FI Cam with a OO-152 CAM for a Carb set up on my 1.8. It's pretty well understood that the conversion from FI to Carbs will never work right with out changing the Cam. Hopefully this isn't the case with your's as the cam conversion requires pulling the engine out and splitting the case to get to where the cam is.
Did the throttle plates fully open during the test? Also, ensure the pedal stop isn't restricting travel.
An exhaust system from Tangerine Racing (racer Chris) is less expensive than spitting the case. The 'while you're in there' syndrome can be a pain. With the displacement, looks like you need something different anyway. Bonus with a Tangerine is a provision for some heat and more importantly in WA, defrost.
Evidence that the mild camshaft is the limiting element (or part of it), I found http://www.originalcustoms.com/2056.php. The ad includes a dyno run that peaks just short of 125HP around 5400RPM. I'm guessing that chart is crankshaft horsepower (BHP) rather than wheel horsepower (WHP).
Would you guys reopen a new engine just to change the camshaft? I'm more inclined to rebuild the transmission, fix the leaky rubber seals, track down the oil leaks, before worrying about being only slightly faster than stock.
That Original Custom is a 2056 making 125HP with the same cam as yours. You had issues including a slipping clutch. I would fix the oil leaks and the clutch before considering the cam or header. I would be willing to bet that you got a bad dyno run and after you fix the clutch you get more power. Stock is 95 horse power.
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