My car is a 1973 914 2.0 running dual Weber 40 carbs, an Aircooled.net SVDA vac advance distributor (vac port connected to dual carbs) and a Pertronix electronic ignition module.

Here in NJ, on a 80-90 degree day, the car runs great on the back roads ranging from 30-45 MPH. Using the dip stick temp gauge, she runs around 180-195 for oil temp. If I take her up ont the highway and run the car at 65-80 MPH for 10-20 minutes, the temp will run up to 220-240, based on the outside air temps, which seems too hot.

I assume that since I am fine on the back roads, my flaps and fan are clear and working fine? I do have 100% of the factory tins in place, and from 180-240 degrees, the car runs strong at all temps.

I am thinking that I have a problem and would like to rule out some things. Here's my list of things to try. Please feel free to comment or make additional suggestions.

1. Change oil. I am running 10W-30 now. Have some fresh Brad Penn 20W-50 on hand. Could an oil change help?
2. Drop the oil screen and check for any sludge or blockage which may be impacting oil flow.
3. Check timing on the SVDA dizzy. I am wondering if it's advancing a little too much on the highway? Per John's instruction, when we installed the dizzy we set timing to: 38-45 Total Advance (hose connected) @ 3500 RPM.
4. Pull spark plugs and check for lean conditions.
5. Check carbs and idle jets. Not sure what's in there, but I hear that I want idle jets of 50.

i think you miss read his instructions.... try 28 degrees total advance. hose on...then reset your idle to 800 rpm and reset your mixture screws.

I agree with Doug.

I've been using Brad Penn 10/30 in my DD since last year.
Its a 1911 running D-Jet, with the stock cooler remote mounted under the trunk and a 180 deg oil thermostat inline.
Oil temps don't go above 220 even driving at 90mph for 15 minutes straight in 90+ air temps.
Changing to 20/50- won't improve your temp issue.
However, if you find that oil pressure isn't sufficient when the oil is very hot, you should go to a higher viscosity.

Guys, here's John's timing settings, copyed and pasted right from the instructions email that comes with the SVDA distributor. Are you still saying these are incorrect?

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Now it's time to set the timing. Reconnect the negative side of the battery, and turn the key on, but don't crank the engine. With a test light grounded on the engine case, put the other end on the negative terminal on the coil. Very, very slowly, rotate the distributor counter-clockwise, until the test light lights up. The light will stay lit up for a few degrees of the rotation, so it is important to stop turning the distributor body as soon as the light turns on, when rotating counter-clockwise. After this, simply tighten down the distributor clamp, and your engine should start right up. If you have a timing light, get the car started up, aim for 7.5 BTDC at idle FOR NOW, the hose connected or not should not matter (if it does that's the wrong vacuum port). After you set that, reconnect the vacuum line. Depending on where your timing was at idle with your old distributor, you may need to re-set your carb. To verify the correct operation of the SVDA, the timing should be

A) 28-30 Total Advance (hose disconnected)@ 3500 RPM.
B) 38-45 Total Advance (hose connected)@ 3500 RPM.

Let it idle and re-check the timing, you can now use this timing setting to set the timing at idle, though we do recommend you check the full advance settings to make sure the SVDA is working properly at both idle and full advance.
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Rather than take the car back to the shop, could someone walk me through how to properly adjust my own timing? Should I pick-up a special type of timing gun?

Thanks

I'd set the timing at 28 btdc, vac advance disconnected.
Then verify that the idle and vac connected settings are in range.

On the fan, 28 btdc is right about where the last fin is before the heavy rib. TDC is around 4 fins from the heavy rib.
Some fans have a mark at 27.

A fancy timing light allows you to preset the advance you want and time to the TDC mark at 3500rpm. With a plain jane timing light you set to a 28 deg. mark painted onto the fan.

Thank you, Chris!

check your mixture too. lean running by even a small amount can cause over heat. get an O2 meter on the tail pipe or read the spark plugs

What's a good range for O2 on a carbed 914?

depends on your engine, but in cruise a bit on the rich side is ok on an aircooled car, else they will run hotter. you might try around 12.5:1 and see if that effects your temps. you got carbs, so go one jet size bigger and see what happens. a spark plug reading can help you. if your carbs were set for the old gas, they will run too lean with todays oxygenated fuel.

old gas =gasoline

new gas = gasolean

That's actually a common misconception.
The engine will run plenty cool and get better gas mileage during light throttle operation if the AFR is between 16-17:1.
For full load operation you need the mixture no leaner than 13.2:1, with 12.5-12.8:1 being used more often to create larger a safety margin.
Anything between 14-15:1 will make the heads run hotter.

I would suggest you listen to Chris.

Chris has taken the time to develop a 4 channel EGT system, a CHT system, and an AFM system that he trusts.

Based upon those three levels of research and testing, its obvious to me that he really cares alot about heat and mixture on these motors...

He has done quite a bit of testing on both street cars and track cars to learn tons about how to manage heat.

He even has is own horizontal cooling fan setup that he makes.

With the level of his real world testing, I would trust his results quite a bit...

He may not have invented some of what he sells, but he has tested enough of them to trust what he sells as good technology....

My point would be, listen to Chris.

rich

And I talk with my dad a lot.
He's a PhD aerospace engineer and has more than 60 years experience flying small planes with aircooled engines. He tends to maintain a larger safety margin than I do.

Sorry about the hi-jack...
Chris, you run Brad Penn 10/30? How does that work as far as oil pressure and leaks? Any difference between that and 20/50?
Will my engine run cooler with 10/30?
Thanks,
Mike

I was running Brad Penn 20/50 based on the recomendation of Jake Raby, but after some in-depth reading online, I decided to try 10/30. Now I'm convinced that, for most of us northerners at least, 10/30 or 10/40 may be better year round, than 20/50 ever.
Some people think the thicker oil bypasses the cooler more readily, so they use lower viscosity oils and claim their temps are cooler as a result.
20/50 seems to make the pressure too high until the oil is very hot. Well my engine doesn't get that hot except when I beat on it for long intervals, or let it idle for a long time.
10/30 only seems to get too thin above 220F in my engine. That's why I'm thinking 10/40 may be a little better.

Thanks Chris...I'm going to try Valvoline VR1 10/40 if I can find it...
Mike

The valvoline no longer has zinc in it, IIRC

Damn...not even the Vr1?

Want oil .... The "new" Kendall Gt-1 oil with Liquid Titanium has the appropriate amount of Zn in it. I've been running it in the 2.7L

Probably not available in my area...

There are some motorcycle oils that still contain enough zinc.
I don't have a list though.
If a particular oil meets the API SM standard it definitely doesn't have enough zinc.

1. What is the safe range for oil temps? Is 240 too hot?

2. Are those little dipstick thermometers accurate?

3. Where can I get my hands on an O2 meter to check my mixture? Do you have to go to a shop?

Zinc? Do we really need zinc on a fully rebuild motor that's broken in???

I'm using Castrol 10 W 30

How long do you want your fresh engine to last?
Oil purchased at your FLAPS isn't a good choice to protect against cam'lifter wear.

I've asked for oil with zinc and I get looked at like I"m nuts, including the place that has a guy that has been a previous Porsche owner.. .

Educate me please.

I agree with Rich's take on Chris as well.

Plus, his horizontal cooler is "Cool Beans"...

If I can't find oil with zinc, can I just scrape the galvanized coating off of a few nails and dump it in the oil?

FWIW, there are some oils left.
I've rambled already. Take it for what it's worth. Don't complain.
http://randbaldwin.com/?p=326

Yes. Especially if air-cooled.

Right, run with that. Just don't breath the exhaust. Haha.

A good article here: http://www.lnengineering.com/oil.html


Jim

Well, what Chris has done may be nice, accurate, and works on his car. I too have worked with instrumented 914 cars, head and oil temperatures, and wide band mixture gauges. Spark Plug color was also checked for different test conditions.

We have hooked up several MPS to work from inside the cockpit where an assistant can tweek them while on a flat level test run.

After collecting lots of data, what we found to be true on the way these cars are set up.....Lower temperatures occured near where I suggested, a richer mixture. Leaner mixtures, not even as lean as Chris suggested caused over heating in little running time.

These tests performed on two engines, both 96 mm pistons, one a Raby FI cam, one an Elgins FI cam. SS heaters, and Bursch exhaust, stock 2.0 l D-jet. 91 Oct Fuel. 28-30 degree advance. fuel pressure varied 28 to 34 psi. approx 75-85F ambient.

I cant explain the differences in results, but my reported results are not a "mis-conception".

I suggest anyone with a desire to tweek the MPS have some basic temp and O2 gauges and abiltiy read spark plugs to confirm the best adjustment for their engine.

At anyrate take both advices for what they are worth, and try your self. You know now that even engineers with well thought out experiments can get differing results.

It should be clear that I care about these engines and their cooling, and mixture needs. (which is really not uncommon at all within the classic car hobby population)

I'd like to hear about R Towle's own MPS test results, rather than hear someone parrot another experimenters results.

R Towle...Did Chris really develop the Four Channel Exhaust Temp Gauge that can be trusted??? How old is Chris, he must be over 100? Amazing he still races.

I talked to my Dad last night.
Aerospace engineeer, not a pilot, but he works on stuff that goes a lot higher (past edge of solar system) He has had plenty of experience as a test enginner for all sorts of fixxed wing and rotor craft. He does car stuff to on the side, including thermal testing of components for Telsa cars. Oh and he has been an aircooled motor mechanic since 1958 as a hobby.

Your Dad and my Dad have a lot in common, maybe yours can take my Dad flying sometime.

Oh this is so warm and fuzzy, feels like family.

Wingnut, do you have some test results you'd like to share?

Just stop by my shop sometime with your Dad.
If my dad's not travelling, there's a good chance he'll be nearby.
He loves to show off his Ryan STA restoration project in the corner of my shop, and his Bonanza is hangared only 15 minutes away.

If you don't live anywhere near Hartford, don't let that stop you.
Elliot Cannon was here from CA, and Mary Shortridge flew in from Kansas with her father and uncle for a visit.

BTW, I'm nowhere near 100 years old. My dad is only 83.


What did one firecracker say to the other?
.
.
.
My pop's bigger than your pop!


But seriously,
If one has adequate instrumentation and knows what to shoot for, lean cruising with carbs or FI is an excellent choice for cool temps combined with great fuel mileage.
Here's a little light reading on the subject: Mixture Management and Cylinder Head Temperatures

So, how does mixture affect cht’s? Here is Lycoming’s chart showing, in a general sense, how mixture, egt, cht and power are related:






Well a bit of data is better than the daddy bragging, or mindless parroting.

The refereanced chart shows cool running at rich mixutes and in lean, but at rich mixtures power is higher. So have it either way, trade off either way.

Although engineers may not always agree, both are generally right.



As for Parrots who post with no first hand knowledge. Parrots are just bird brains. I object to someone saying to listen to some opinion over another becuase in part, his instrument are ASSumed better while not knowing anything about the instruments, nor technique used by the other party, or claiming that only one view point is backed by someone that cares about these issues, impling the other party does not care. Bird brained logic at work if you listen to parrots.

i am running the amsoil hot rod 5/30wt- zinc fortified oil. 28 degrees full advanced svda. idf 40s. with my idle jets as lean as i can possibly get them. some where in the 16 -17 A/F at cruise....and my mains are jetted to 12.7 a/f. its been right around 108 degrees on my way home from work all week this week. my oil temps peak at about 225 and my cylinder head temps are between 360-370. i am using a 4 channel air craft cht guage. digital a/f gauge and digital oil temp gauge and digital oil pressure.

im gonna look up my instructions for my svda and see if it says the same. i got mine from john also. seems strange he would tell you 38 at full adv.

the vacuum advance should only be kicking at part throttle. (light load). then beyond that it should settle back down to 28 degrees.

200 posts and you are talking trash already.....
You won't make friends that way.

Have I tuned an mps, yup, more than once.
I never parrot, thanx

Ape who are you? What are your credentials? All you do is come in, talk shit, and try to disprove others. Wtf? You have an answer for everything but it seems all your posts are just an attempt at contradiction. It gets old and nobody seems to like you. I am certainly no 914 God but PCNA respects my opinion and takes it without question. Can you please try to explain your obviously superior background to the rest of us so we can try to filter out the bullshit from others?

Your friend Jon.

He's our thread locker. Whenever an informative thread comes along he makes a few post and BAM. The thread is locked. Now this one is gonna locked pretty soon too.

Here's my question now: Of the total "oil product", what percentage should be Zinc alkyl dithiophosphate? The Brad Penn oils have a max of 0.1 to 1.1 % according to the MSDS. Castrol GTX has 5-10% according to the MSDS.

I bought a supplement, but haven't put it in yet because I need to drain some oil out first and don't have the facility at home.

This all has made me very curious and a teeny bit confused

Wow.

Talk about going "Ape-Shit"

Also, work on your diction and don't be so BOLD.

*sighs* best thing to do with that type is ignore. They only participate when they get attention.

Dear friend jon. i never tried to disprove anybody. i simply suggested trying a richer mixture, some one later said it was a misconception to run richer and two other folk added with no technical content, that they agreed with the person who said he prefered lean mixtures. Instead of getting into the tech details, we were told to listen to the person advocating lean mixtures for the simple reason that he cares about these engines and he has some neat gauges and built a cooling fan, and his Dad is a pilot.

I never even once tried to disprove that the person advocating lean running is wrong. In fact it is clear from his data we both are right, rich or lean running can cause cool running, and I admitted that pretty clearly.

posts that in effect say to believe one set of data over another becuase it is assumed his gauges are better, or he cares more about engine cooling or his dad is a pilot have nothing to do with the technical issue and such comments are just noise that deflect the real issue of why this guys motor is running hot.

the orignal posters hot running issues probably have nothing to do with zinc in the oil but may have a to do with mixture along with other things.

for me richer made cooler running, but the original poster will need to try it to be sure, he may even try to go real lean, and see if that helps his motor stay cooler.

Never did i try to disprove racers chris's concept of lean burn, not once. What i did not like was the implication by two that I was wrong becuase I dont have good gauges, or dont care about cooling issues, both assumptions are false and needed correction.


So it turns out both me and Chris are correct dispite differances, we both have resonable gauges and experimental techniques, and both care about cooling issues.

Chris:
To get the lean burn 16:1 to work do you have to alter the spark advance to work with it in anyway? and do you run a higher comprssion to compensate for the operation at less than peak power? I know these are some of the tricks to lean burn, just wonder what it takes to get it to work on a 914 motor with D-jet?

How can we get both power and lean burn out of our 914s along with cool temps. My 914 seems to run great, plenty of power, low head temps and low oils temps at a 12-13.5 to 1 AFR.

From everything I have read on this site, until today, I came to an understanding that I want my 914 to be rich. Bleyseng says to set the MPS on the rich side, the factory set the MPS on the rich side. I am confused.

I also have a '92 civic vx that goes into lean burn, and while I dont monitor temps I do know that when it is in "lean burn" I have no power, but great mileage. I do monitor the voltage output of the wide band O2 sensor the higher the output voltage the leaner it is running. This is all controlled by the ECU. For this car to have any power it need to be running rich and the v-tech needs to kick in at 3k rpm.

Link to suggesting a rich mixture

If my understanding is correct, peak EGTs would be slightly lean of stoichiometric. Continue leaning the mixture, and EGTs start to go down again. Lower EGTs can also be found to the rich side of stoich.

Running somewhat lean at cruise, under very low load conditions, is generally not harmful to anything as long as the temps are within bounds. It only takes ~10 HP to keep a car running at speed on a level freeway, so not having much power is a non-issue.

The "lean-burn" Hondas run very lean mixtures during cruise. Some of them take control over the throttle valve directly, opening it up much more but then leaning the mixture out to where there is just enough power to maintain speed. These systems require relatively sophisticated controls (including a wide-band O2 sensor that is directly read by the car's engine management system) and a degree of fuel mixture control that is way beyond the 1960s analog computing tech in our cars. They may also require some fairly sophisticated cooling system design to make sure temperatures stay under control--but I'm much less sure on that.

So comparing Honda's lean-burn tech to the notion of running leaner than peak EGT is pretty much apples to oranges.

With the weird old control systems in our cars, I prefer to try to keep the mixture a little rich. Because it can relatively easily be richer or leaner than what you're trying for under certain circumstances, and having it go near peak EGT mixture (for a long while) can ruin your whole month.

--DD

Dave, You are right about comparing the Honda to the VW engine; they are two different fruits. Some Hondas are designed to run lean utilizing the v-tech technology and the wide-band O2. But as far as I know, which may not be much, the VW engine is not designed to run lean.

My main confusion with this thread is that now I am reading that it is ok to run lean to reduce oil temps when every other thread tells us to run our 914s on the rich side to reduce oil and head temps. With out the proper monitoring equipment an arbitrary lean mixture is just asking for trouble.

Is it possible for the OP to set his carbs to run lean while cruising on the freeway and rich in other driving conditions so he has power? Or does he need to drop hundreds of dollars into monitoring equipment to achieve this? From the OP he is monitoring his oil temp with a dip-stick temp gauge. Not very high tech no expensive.

Many guys have added a second oil cooler to help reduce oil temps. Some have even gone as far as changing the entire air cooling system (to the horizontal fan set up) to reduce temps.

from what i know about lean burning and aero engine is that Charles Lindberg (First man to solo fly Atlantic Ocean) taught the lean burn technique to the US military in WWII in P-38 fighters,. He extended their range in the Pacific fighting. (Lindberg actually shot down some jap planes, although he was officaily banned from combat, (the President determined it would be bad Press if a hero such as Lindberg was lost in combat or worse, captured). Lindberg often made excuses to go on "test runs" with the rest of the planes into combat. He got into the thick of it several times. Lindberg got a lot more milage out of the engine by going leaner than the crews thought they could. however that was a big fat water cooled inline motor, super charged, running 120-140 Octane.

Lean burn to run right needs to have other modification to be done, timing is often advanced, as the lean mixture has a slower flame front speed. High compressions can also be used to compensate for the loss of power lean burn gives.

makes me think .....If one would wire in two MPS one for rich sporty driving, one for lean cruising, and one could take advantage of some adjustable spark advance, one could maybe make a "sport/ecomony" switch on the dash.

Still interested in hearing how racer chris gets his lean burn to run best?



I suggested first to go richer because I have found more often than not cars will be lean rather than rich when they have these kinds of problems, Even a stock factory set up car will be running too lean on todays fuel, so my first reaction is to try to richen it, if richer makes the car run hotter, then you know your on the other side of the curve and you can try the leaner route. what ever works for your engine and driving needs.

Like tradisrad thinks....Twisty roads, rolling hills, cars to pass, and you will probably prefer richer, if your steady on the interstate, leaner might be nicer if it can save some gas.
deviate a lot from factory specs in mixture and you have to start changing other things to maintain drivability. all a trade off.