Afternoon!

My 914 has a 1.7L engine(original) and I am running a pair of 36IDF carbs. I have rebuilt them personally, had another relatively local 914 specialist rebuild them and I am still not entirely happy with the way they perform....

Transition and coming on to throttle up to when the main jets come on seems to be the issue.

Is there a rebuilder/cleaner that everyone on here recommends? I figure some sort of ultra sonic blasting to clean out the ports/chambers that I am not able to get to would be the best.

Any insight?

Possibly also rejetting suggestions might be good as well.

Thanks,
Casey

Did the car drive alright before? Sounds more like a jetting problem than a cleanliness problem.

What jets, venturis, etc. are you running in the carbs?

Previously was using a single carb...

Dont want to get into all of the money i have spent getting it sorted.

3 different parties have confirmed that I am running the correct jets/vents.

If I recall... 50 Idle 140 Main and 190 Air. Vents are likely the stock size. Once the carbs go on main(2300 RPM+) it runs great. So i really feel that something is wrong in the idle circuit. There is a bit of hesitation on throttle tip in and in DC traffic there is a lot of on/off throttle.

I have heard that this guy is the guru but have not used him YET.... Not the least expensive but right is right...

http://www.aircooledengineering.com/carbparts.htm

Let me know if he helps you...

Steve

I sent my Dellortos to Air Cooled Engineering. They aren't cheap, but they found a lot of problems I wouldn't have even known to look for. I haven't run the carbs yet but their rep is solid.

You should take a look at performance oriented. Paul Abbot has been very helpful in repairing my webers that had a couple of idle passages blocked after sitting for 20 years.
performanceoriented.com

Paul's the master but is backed up a ways.

Aircooled is here in town. Good guys.

Art at Aircooled Engineering has been prepping carbs for me for almost 20 years. He has not once ever disappointed me.

Can't say that about anyone else I've worked with for that long.

Casey, have you bought the Bob Tomlinson Weber Tech manual? His jet settings are right on the money, and if everything has been rebuilt and there are no major mechanical issues, you might cross reference your jet sizes with what he has in the book. Kev (Rhodyguy) was my Obi-wan on this one and all he had to do was tell me "check the book." PM me with symptoms and I'll try to see if I can give you any tips from what I learned before you go shelling out more money.

Every metropolitan area should have somebody who can do what you need, but like everyone above has posted, the guy above all guys for aircooled applications is Art Thraen of Aircooled Tecnology, ACE, www.aircooledengineering.com.

On the other hand if you're going to run carbs it's probably a good idea to start learning now, and rebuilding them yourself isn't a bad way to start. Go all in, especially if you're on a budget, like most 914 owners. As suggested Tomlinson's Weber book is a good place to start, get it at CB Perfromance, www.cbperformance.com.

Thanks all for your input. I have been through these carbs twice(w/my father who has some SU/Zenith knowledge), have been to a local guy that restores very high end vintage cars(300SL/AC) and also to a guy that, in the mid atlantic probably has the nicest 914 and builds a lot for vintage racing.

I will PM george as I looked and that book is ~100 on amazon. If nothing there they will be going to see Art!

Casey

i don't think you're fully on the main jet circuit @ 2.3k. what are the specific symptoms you're experiencing? "still not entirely happy" is a little too vague. does the ~100 mean tomlinson's is $100 @amazon?

get the book. READ the "bolt em' on", "how they work", and "trouble-shooting" sections until you're familiar with the terms

there's lots of possible solutions. from worn/missing tiny o-rings and up. verify the 'choke' and the jet sizes. there should be #s indicating 'choke' size on the top lip. remove a filter and look down the carb, engine not running.

show us your carbs (detailed pictures), linkage, distributor, and how your plugs look. swipe your finger in the exhaust outlet. does it come out sooty black?

remember, your 1.7 is little more than a 1650 T-1 displacement wise.

ACE is not cheap by any means but the stuff is right when you get it back. Art is helpful with a phone chat before they start.

k

You're sure that it is the carbs? Two people, yourself included have rebuilt them and you're sure the jetting is right and there is still a problem? You don't have a vacuum leak at the bases or a balance problem?

Rule out another problem before you spend bigger money on the same solution.

With Rob and Kevin. As I sent you in the PM, you probably want to blame the carbs last at this point. It often is them, but it could very well be something simpler and cheaper. I.e. adjust the valves, verify timing and ditch the crappy 009 distributor if thats whats you're using. Also, ensure you have a quality fuel pump and regulator and adequate (3.5 PSI) fuel pressure.

THEN you can fuch with the carbs. After you follow Kev's advice and read Tomlinson's stuff, of couse

Welcome to the madness my friend.

adequate fuel delivery and 3.5# MAX.

A hundred bucks? Dude! HERE, $12.95 brand new at CB Performance (they're the publisher):



The book has a troubleshooting guide so you can go through it all systematically and identify the real cause of your problem before spending anything more on the carbs. They also have most repair/rebuild/re-jet parts you'll need (as will Art at ACE or Pierce Manifolds).

EDIT: For one of the best rebuilding/re-jetting/synchronizing multiple carburetors guides take a look at the VW Tech Articles section at www.aircooled.net. I've referred people to the synchronizing article for years with all positive feedback. And John there is a super tech resource, stocks only the real deal good stuff, no Chinese chrome.
.

Unfortunately, everything else must be spot-on before you tune the carbs. Make sure your getting spark to the chambers, fuel is at the appropriate pressure and clean, valves are properly adjusted, if you don't do this, your tuning to overcome the problem and not to optimum performance. Once you have done all of the background tuning, you really need to know what the engine is doing under load as far as the Air:Fuel ratio is concerned. Without that knowledge, no one can really tell you that your jetting is spot on. I'm not sure what they based that on but in general, people run fat A:F ratio to overcome other problems. Type IV motors tend to like a fat idle but tighter control above that. Remember, you are cruising on city streets on your idle circuits most of the time. I run both of my cars at around 13.5:1 target. One is a fuel injected 200+HP Type IV, the other a triple Weber 240Z. You can get that kind of control but you have to have all your other ducks lined up and quacking in unison before you do...

Remember, Einstein said Repeating the same behavior over and over and expecting a different result is the definition of insanity. Back up and reconsider everything else.

The only issue is really throttle response... On throttle tip in it always bogs rather than picking up. To overcome this you need to rev to ~3k and slip the clutch higher so that is doesnt bog. That is really the only issue with the car. From the research that I have done it seems like it is a problem with the idle circuit of the carb as it only happens at lower RPM through transition.

The Valves were adjusted roughly 300 miles ago when the heads came off to replace the seals for the pushrod tubes.

I will order that book right now... Only copy I saw was on amazon for $102.

They have a "total douche" $20.00 minimum.

You mean CB Performance, right?

Yep, i caught that.

The guys at ACE were very nice and insightful. Their suggestion, since multiple people had been in and through the carbs was to focus on the dist... If i recall I have an 050 which they said had a dead spot. He suggestioned I go for an SVDA. My current Dist doesnt have a vacuum advance. Would going to an SVDA dist be a good first move? Suggestions on which one?

Thanks

Sorry Casey, just saw this after I replied to your PM. The 050/009 are bad distributors for a car that doesn't see extended periods at high RPMs and is notorious for a flat spot down low.

John at Aircooled.net sells new 034 SVDAs, which is what you would want. You may not have the *correct* vacuum ports on the 36s. Again, you can still run the SVDA, but will miss out on some of the off-idle advance the vacuum provides with the SVDA.

Thanks to all of you for the input. Ordered a Tangerine Mallory from Chris.

Looking forward to the weather getting nicer.

Casey

Good deal. Chris will treat you right. He makes great stuff, and as I told you in the PM, he knows these engines well. One day I'll make the step up to his Mallory. Glad you did business with him.

the 050 is not notorious for that...

yes the 009 is a bad distributor for these cars
it does have a flat spot due to the ignition advance curve

the 050 does not have that problem.

I will bet you that you have an 009 if you are having problems.
I doubt you have an 050, but if so I'll buy it from you.