My base timing advance is a little weird, and hard to describe.

heres the points that I remember. Base timing is at 2" hg. I begin retarding the timing at 1" hg . total is maximum timing from vacuum advance.

at 1000 rpm, base timing = 18, total timing = 28, vaccuum at idle= 17-18"
at 3000 rpm, base timing = 31, total timing = 41.
at 4000 rpm, base timing = 34, total timing = 44

The vacuum advance is adding 10 degrees between 21 and 8 inches hg.

Within the peak vacuum advance timing is where closed loop is engaged, and the afr's will be approximately 14.5:1 between 22 and 12", and then depending on rpms, the afrs will go between 12.5 and 11.5 between 12" and 8" and then back into the 12.8 range as it gets closer to boost.


I think you are running into issues with copying the stock timing, because the timing with the stock set-up was done with carbs that are more or less going for "rich best power" + a safety margin, and were done with leaded gasoline, which doesnt "act" quite the same as non leaded gasoline at the same approximate octane. The octane ratings now cant be compared directly to the one used in the 60's because the standard has changed. 92 now is "approximately" the same as 98 or 100 then but now we use r+m/2 for octane, and I think the old standard was using just R or "research" method.

I think you will find that if your max light load timing is between 44 and 46, you wont have any trouble going a bit leaner and the engine will run cooler that way.

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car
Test Start#2 [www.youtube.com]

63turbo Wrote:
-------------------------------------------------------
> KenHenry Wrote:
> -------------------------------------------------------
> > Thanks everyone. Wow Mike, that must have been a real thrill running your Lotus on the track! I drove the Corvair a few times on the carbs with the WB02 installed, and was surprised that it was so consistently down around 13 AFR. I would like to test my WB02 gauge against a known good one. Mine is the Spartan 2. I should also peek in my primaries to see what size jets were in there...
> >
> > It appears I have to rethink my revised PCV system with a true PCV valve and the fresh air tube running from the oil filler to the air cleaner. I'm getting excessive oil in the air cleaner assembly. An ideas of how I could baffle it to keep oil spray from blowing up into the air cleaner? The engine is likely worn but doesn't smoke and I never had this issue on the carbs. Perhaps just a metal screen? Alternatively I can revert back to the stock fixed orifice system... Ken
>
> One of the benefits of carbs is the ease of getting a steady air fuel ratio... this has everything to do with the continuous flow of fuel and air. The downside is that ideally, you want the fuel air ratio to vary as the load on the engine changes. Really hard loads should produce a richer mixture than for a lighter load. This is both for safety reasons and getting the getting the most out of the engine... lean best power is around 13.5:1 rich best power is around 12.5:1, lean best torque is around 11.5:1 rich best torque is something like 10.5:1, but it is senseless to go that rich! the distinction is that the timing can be stronger and produce better torque, but if this same rich best torque timing is used with the best power afr's the engine will detonate. Being able to manipulate the timing for the afr's and current load is one of the many benefits of EFI.
> I bet you had the same oiling issue before with the carbs, but you just didnt know it, the carbs were likely washing the oil away with gasoline. A air/oil separator can do wonders for things like that!!

On my Lotus, and also my 2007 Z06 Corvette, getting oil accumulation in the intake was a problem. On my Lotus with the Zetec 2.0 L, I made an aluminum “catch” can that was connected to the crankcase vent. It would accumulate 3 to 4 oz of oil per race day. With the Corvette, I had to keep pulling the intake hose between the air filter and throttle body to clean it every hour of operation to keep the oil from messing up the MAF sensor. On the Corvair, make a catch can with one hose from the crankcase vent and the other near the air cleaner intake. As the engine pulses, oil fumes can accumulate in the catch can. Use a bronze sintered plug on top of the catch can for proper venting. My issue with the Zetec on the Lotus was the redline was 8500 rpm.

Mike

My favorite "theory" is the 55-57 degrees of timing that the stock VA+distributor timing allows. The reason this normally doesnt blow engines up or break rings is only because the timing is SUPPOSED to fall off with load and not go there... it can be dangerous though if the car had been re-geared... then theres too much rpm and vacuum advance, the load from wind resistance that would normally drop the timing is not there anymore and causes the burn to complete well before the piston is past tdc (like it is supposed to!!). A guy I know that has a 3.89:1 differential in a 140 with a powerglide busted a bunch of piston rings recently and the same timing issues that this low gearing causes is what is suspected. The other thing that can cause this same thing is oil going down the intake leading to pinging, and the pinging would then lead to detonation and that broke the rings.
Next theory is sometime in the past is "someone" tried regular gas or simply old gas... octane tends to go away fairly quickly with modern gas formulations, and should NOT be trusted if it has been sitting for six months or longer, Ethanol added or not!

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car
Test Start#2 [www.youtube.com]

The rear gear is a 3.55 and my tires are slightly undersized: 185/70r13. At least it's easy for me to adjust the timing table now to reduce advance at cruise. I've always run 90 octane ethanol-free and never had pinging, but the rings have likely been broken the whole time I've been driving it. I think I'll rebuild it as a big bore 3.0L! Best, Ken

Ken Henry, Rochester, NY USA
1965 Corvair Corsa
140 hp, 4 speed

What about the ridge at the top of the cylinder? Can't that break the top ring if not removed?

David Clamp


1965 Corsa convertible - 140 4spd/3.55/AM-FM

2013 Mustang GT convertible - 5.0, 6spd auto, Procharger i-1

2003 Miata SE - 6spd manual (wife's toy)

"Victory is mine!" - SG

Norman, OK

Unfortunately I don't know much about the history of this engine. I changed the oil pan gasket a few years ago and found a few sections of compression rings and oil control ring in the pan. Not sure if it was debris left over from a previous repair or came from the other side of the engine that I haven't torn down yet. Stay tuned...

David, I don't think they broke during disassembly if that is what you mean. I pulled the cylinders out over the top of the pistons and there was little resistance. The cylinders definitely have a ridge though. Here's a photo I have of one of the pistons that might speak to the ring lands? I can try measuring but rest assured I don't plan to reuse the pistons. Ken

27B2B3B7-D6E5-4DC2-8979-5AAFE7EFEE06 by kenhenry_06268, on Flickr

Ken Henry, Rochester, NY USA
1965 Corvair Corsa
140 hp, 4 speed

I was referring to the fact that new rings will break if there is a ridge at the top of the cylinder. If someone slapped new rings in and didn't remove the ridge, broken rings can be the result.

David Clamp


1965 Corsa convertible - 140 4spd/3.55/AM-FM

2013 Mustang GT convertible - 5.0, 6spd auto, Procharger i-1

2003 Miata SE - 6spd manual (wife's toy)

"Victory is mine!" - SG

Norman, OK

I finished taking everything apart. The rings on the right side of the engine (1,3,5) were all intact. The #5 piston and rod are replacements (unmarked) and there are two #3-marked rods in positions 1 and 3. The camshaft is an 891. I can feel a slight groove on the larger lobes. How much wear is acceptable for reuse? Ken

75C37E8A-5279-43AD-8901-D5EFB6A88A28 by kenhenry_06268, on Flickr

D1444265-74EE-43BE-974B-AE852501D5B7 by kenhenry_06268, on Flickr

Ken Henry, Rochester, NY USA
1965 Corvair Corsa
140 hp, 4 speed

That cam is totally shot. I'll bet the lifters look terrible also.

Joel
Northlake, TX
5 Ultravans, 141 Corvairs and counting...

The ring lands are peened over from being beaten so much. The clearance appears excessive from the photo. Aside from not reusing because of the wear, the heads would likely crack off of the pistons next if you did reuse these.

C.A. Rose
Metairie, LA
1962 Spyders

So I've made a little progress on the engine. A local shop checked out my crankshaft and polished it, said it was standard and reported back a rod journal diameter of 1.880! This seeming impossible, I bought a set of Harbor Freight micrometers and checked it out myself. The main journals are 2.0985 for 1&2 and 2.0992/3 for 3&4. Rod journals are from 1.7996-1.8001.

These values seeming OK, I ordered up std main and rod bearings from Clark's, their house brand. So far I've plastigaged the mains:

#1: 0.0027; #2: 0.0027; #3: 0.0024; #4: 0.0025

These values are interpolated using graphing software and measurements from the images. Photo of the #2 main bearing.

46A743F9-0339-4157-A72F-A36D4F60F4AE by kenhenry_06268, on Flickr

These seem a bit loose, slightly exceeding the maximum specification for 3&4 and at the maximum for 1&2, but with 0.001 mains unavailable I see few other options. Do Clark's bearings tend to be looser than others available? Any thoughts on running these kinds of clearances on a street engine? Ken

Ken Henry, Rochester, NY USA
1965 Corvair Corsa
140 hp, 4 speed

It's fine!

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
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I built a 140 once that barely measured for 0.001 bearings. Since none were available, I built it with standard. It ran great.

David Clamp


1965 Corsa convertible - 140 4spd/3.55/AM-FM

2013 Mustang GT convertible - 5.0, 6spd auto, Procharger i-1

2003 Miata SE - 6spd manual (wife's toy)

"Victory is mine!" - SG

Norman, OK

Back in the Day we could run our 12:1 SBC on 100 octane Pump Gas, theres no way todays 92 or 93 octane fuel would work on the same motor, I dont car what the formulas says. If todays 93 was the Best there was in the 60s every Spyder would have detonated the rings to pieces just like this one, let alone pound the bearings to death or melt a piston. For that matter every Muscle car would have the same issue.

1964 Bill Thomas Monza Replica Racer
1964 Spyder Street Car
1998 Honda Prelude Dirt track car
1967 Crown V8 under construction
Mike Levine
Cumming Georgia
North of Atlanta

Ken
I manufacture a replacement unit for the distributor that puts out a trigger signal and a home signal. Contact me at cartwrightinjection@gmail.com.
It eliminates having wiring and magnets on the crank and runs your oil pump too.

Thanks Duane, that sounds like a great option but the ignition is already done. A drop in kit would have been simpler. I used a 36-1 trigger wheel that bolts to the harmonic damper and fabricated a mount for the VR sensor off the fuel pump retaining bolt. 3/8" ID, ~1/4" long bushings were needed to produce clearance between trigger wheel and harmonic balancer/crank pulley. For some unknown reason the bolt holes in the trigger wheel were larger than 3/8", so I temporarily centered the bushings over the holes using countersunk bolts and attached to the back of the wheel with JB weld... Ken

Ken Henry, Rochester, NY USA
1965 Corvair Corsa
140 hp, 4 speed

Is this top cover OK? I spent some time cleaning the grunge off of this today. The top surface looks cracked but the inner part looks totally fine. Thanks for any input!

38D6AD1D-B66C-47B4-BADD-5B89CDF94AA6 by kenhenry_06268, on Flickr

336C5079-B1F0-41A0-A774-9672AAAC2509 by kenhenry_06268, on Flickr

Ken Henry, Rochester, NY USA
1965 Corvair Corsa
140 hp, 4 speed

Ken - You ought to somehow split this thread out -maybe Matt can help. This is an interesting investigation of the cylinder/head piston issue. It is no longer about the 140 Custom EFI. People may not follow it.

Thanks for the suggestion, Seth. I've started a new thread to cover the rebuild:

[corvaircenter.com]

Ken Henry, Rochester, NY USA
1965 Corvair Corsa
140 hp, 4 speed