S4 Elan oil fouling #1 cylinder

[Chrisrich]

Hello folks.
I've been having a hard time getting #1 cylinder to fire consistently on startup and I've been chasing down what I thought might be a rich condition, but I think it's actually oil fouling (the #2 cylinder exhibits no such problems).
The problem seems to occur when I patiently let the car warm up, or perhaps when I need to turn it off and on repeatedly (you know: working other problems). Next thing you know, I've lost the front cylinder. When I pull the plug, more often then not it's wet with oil, and I've lost the spark. Put a new plug in, I'm back in business. At speed, all 4 plugs look great.
Would we suspect blowby past the rings? I have even compression across all 4 pots, maybe 5% off from the mean.
I'm certainly not blowing much smoke out the back, for what that's worth...
Thanks in advance-

Chris

[RobL7/Elan]

Chris,

Valve guides? If your leak down test is negative and there is not a lot of smoke, valve guides seem the culprit. also check what led to the valve guide issue, if that is the case, ie: Valve clearance, bearings on and on.

Luck to Ya,

Rob

[twincamman]

do a leak down test that will tell you conclusively----ed

[Wayne]

I had a Plus Two that would foul out a plug every couple hundred mile or so. Especially after a high speed run and then lifting off to go off an exit ramp. The fix was switching spark plugs from Champion to NGK"s. I believe the valve guides were slightly worn and sucked oil by during high vacuum times. After switching to NGK BP6ES plugs it never fouled again. I am building a motor for my Elan S4 now, and will probably use Dave Bean bronze guides set to his recommendations.


Regards
Wayne

[tvacc]

It probably will be the valve guides, but I would think it would be all the way across all 4. Valve guides usually wear evenly.

You might have a broken oil control ring. That would still give you good compression, but no oil control.

I dont know if it is worth it to fix it. If you take a compression check....and then take another compression check with about 2 tablespoons of oil in each cylinder, that will tell you how much compression you are losing to bad rings.

If after you do this check and there is no change in the compression...you still do not know if you have a bad oil control ring or not.....

If it is bad enough then you may want to just freshen up the engine.

[tvacc]

do a leak down test that will tell you conclusively----ed

I hate to disagree with Ed...but you can have a broken oil control ring and still have good compression and a good leak down test.

YOu may also just have your oil control rings stuck in the grooves. You may want to put some engine rebuild in a can stuff in the oil for a few hundred miles. I once had an Elan that was blowing oil....and using oil. Car had sat for quite a while and owner did not do many oil changes. After using the engine rebuild stuff in a can....it all came back. No need for engine rebuild.

[twincamman]

welll first off there aint no mechanic in a can ---second if you put two teaspoons of oil down the cylinder it will set you on your ass break your compression gauge and solve all your motor woes as you will have a broken motor ----two DROPS of oil will seal the rings for a compression test ----until you do a leak down test you are just like a dog f44king a football running from end to end hoping --good luck --ed

[tvacc]

welll first off there aint no mechanic in a can ---second if you put two teaspoons of oil down the cylinder it will set you on your ass break your compression gauge and solve all your motor woes as you will have a broken motor ----two DROPS of oil will seal the rings for a compression test ----until you do a leak down test you are just like a dog f44king a football running from end to end hoping --good luck --ed

Sorry....Ed but you are wrong. Just that simple. Now if you put 1 cup of oil down the cynlinders...yes...it could hydrolock and cause issues, but two spoonfulls will do nothing but seal the rings so you can diagnose whether it is rings or valve guides.

But more to the point....
To everyone....you will not break your compression rings...or knock yourself on your ass if you put 2 spoonfuls of oil down your cylinders. This is a old tried and true test (what I call "old guy method") of whether a loss of compression and blowing blue smoke is because of rings or valve guides. I have done it many times and many people I know have done it many times. It will not harm the engine...you...or your tools.

And the stuff I refer to as "rebuild and engine in a can" is sold by companies like Wynns....or Max....Cassite. One is called Restore. It just frees up the rings. A lot of times the rings in TwinCams get stuck with gunk. The rings move in slots and they can get stuck if you let the car sit for a long time. This is especially so if you have an Elan that you drive hardly ever and think you can change the oil every 3000 miles even if the car has been driven that mileage over 3 years. Oil turns to gunk...gunk gets in there and acts like glue. You only keep the stuff in your car for like 500 miles. I then drain it off...and sometimes do it for another 500 miles.....then change the oil.

I have been rebuilding and messing around with twin cams since I was 21. that makes 35 years. I know what I am talking about.


edit...oh...and a leakdown test will not tell you if you have a broken oil control ring. They are different then the compression rings. The only way to do that is by process elimination. If you cannot find any other reason...then it is the oil control ring.

[tvacc]

2 drops of oil may only lay on top of the pistons...perhaps go in to the recesses in the top of the pistons. I usually put 2 drinking straws 1/2 full of oil down the spark plug holes. Is that 2 teaspoons....? I dont know. I just do like I used to do in chemistry class in high school. I put the straw in the bottle of oil almost all the way. I then put my finger on top of the straw and pull out the straw...and put the straw down the spark plug hole. I then take my finger off the top and let the oil go in. I do that 2 times for every cylinder.
Always works for me....

Saying all this....I am seriously not trying to be argumentative. I am only giving you all my experiences with twin cams. I have rebuilt at least 10 of them....and have working about 25 over the years. This is what I have found to be true.

And I am only saying to Ed that he is wrong about the amount of oil that will hyrolock an engine and cause issues....and the fact that a leakdown test is not always going to tell you where the problem is. Sometimes it is only pulling the engine apart that will tell you. I have had at least 2 twin cams that have experienced this problem of the of the oil control rings sticking in the grooves. Great compression, but oil missing from the crankcase and fouling the plugs. Leak down tests were inconclusive and compression was 165-170 all the way across. And there was no blue smoke after sitting at a stoplight or just starting the engine. (both of which are almost for sure indications of bad valve guides).

Again to all...this is my experience. I guess everyone has their own opinions about working on engines.

[redelan64]

I had a continuing problem with number 4 fouling and a wet plug on my S1 Elan. No I don't have a power booster for the brakes so that was ruled out. I had replaced the guides and the engine was basically fresh from the last overhaul - about 6000 klm.
I decided to remove the head to fit new oversize cam buckets because I got sick of the tick tick tick. When the machinist vacuum tested the inlet port for sealing of the valve seats, number 4 wouldn't hold. Investigation found that the valve spring seat had been bored a fraction too deep by a previous machinist for high lift cam clearances or enthusiastic "porting" of the inlet had gone too close and the oil around the spring was being sucked through the porous casting into the inlet port when the intake vacuum was applied - closed throttle on overrun.
It was almost impossible to see behind the valve guide. We used a trick epoxy from the spring side and no more wet plug.
It's something to watch out for when people start machining or "port and polish" as the castings are not consistant or generous on thickness.

Hope your oiling is more straight forward but I thought it was worth sharing.

Craig

[elansprint71]

What system is your crank-case breather? My car came fitted with a pair of shallow K&N pancake filters on the carbs and all the junk from the crank breather was routed through one carb choke; result- oil fumes going through that cylinder and oiling the plug, etc.
I reverted to the original S1 version of the breather and vent the fumes to atmosphere.

[Rob_LaMoreaux]

Chris,

Since it is #1 cylinder I have to ask...Do you have brake boosters?

When the brake boosters fail they often start to leak into the vacuume line and the vacuume takeoff is from #1 cylinder. This off course causes oil fouling of #1.

Secondly, since you are in the US and the car is a 1970 you most likely have Strombergs. The way the stromberg carb is paired to the cylinders is, well, just wrong. They should be paired to 1 and 3 and 2 and 4. Anyway with the stromberg setup #2 and #3 cylinders run lean and #1 and #4 run rich. This is the worst at idle and when cold the temp compensator richens the mixture more. I had #1 and #4 tend to oil foul idling with the stromberg engine until I got it tuned right (DBE 112 cams and I had to go to adjustable needles). The plugs looked like they were oily, but it was partially burned fuel.

So just because #2 is fine doesn't mean the carbs are right, and my personal guess is you just need to not sit idling the car, but driving it.

My car with the stromberg engine and generator hating idling, and would eventually on a hot day have a dead battery and fouled plugs. After I finally got the carbs right it just detested idling, but it would still drain the battery.

With the weber engine with alternator, I haven't gotten the carbs right yet, but they are all uniformly slightly rich, so while I don't get max power it runs well.

Personally I'd disble the temp compensators, then tune the carbs so 2 and 3 are slightly lean and 1 and 4 are slightly rich, then avoid extended idling.

Rob

[CBUEB1771]

When the brake boosters fail they often start to leak into the vacuume line and the vacuume takeoff is from #1 cylinder. This off course causes oil fouling of #1.

Of course this is something to look into. However if the servos are leaking much Chris would also see white smoke in the exhaust and probably notice spark knocking, assuming that the brake fluid is a glycol-base type.

[jkatthehelm]

All but the later heads pool oil at the rear of the exhaust side cam bank; later heads are crossed drilled to the inlet side from where oil can drain down vio padssages originally occupied in the Ford base engine by the pushrods. Early heads can only spill exhaust bank oil over the front into the chain gallery, or run down guides....... if worn enough.
The engine is canted up at the front, exacerbates this problem.
So,
If only #1's fouling I'd be looking below.
JK

[RobL7/Elan]

Given the head design of the early engines.. it still looks like valve guides, only more pronounced in #1 because of the canting of the engine.

Rob
Elan S2, Catherham7