First day at the track smoke problem

[Rich F]

Well I finally got my GTS out to lime Rock today. The right side exhaust started to smoke pretty heavily. We pulled the plugs and none were fouled. Looks like oil smoke (blue). Only seems to do it when I let off the gas. All fluid levels looked OK. I'm going to do a compression check tomorrow. Need to borrow a leak down tester as I don't have one.

Any thoughts on what to check. I also have a call into a local engine builder I work with here in CT for guidance.
Thanks for any suggestions,
Rich

[PanozDuke]

OK, I'll hazard a guess: Valve seal(s) or guide(s) on that head. On decel you get the highest vacuum and that is when more oil gets sucked past the seals and guides. If the compression test is OK, then it isn't bad rings (which usually causes smoking pretty much all the time. Another sign that it is guides and or seals is a puff at start up (since the oil leakage pools in the intake tract while it is not running).

Hope it is something simple and easily fixed.

Mike

[jmimac351]

My experience has been when smoking only at startup it is a valve guide / seal issue. If the compression checks out I'd be looking at the intake manifold gaskets.

[NZGTRA17]

Originally Posted by Rich F

The right side exhaust started to smoke pretty heavily. Looks like oil smoke (blue). Only seems to do it when I let off the gas.

Rich, from symptoms you describe it sounds like the guides. I had the same problem with my car. Guides wore out after 9 engine hours and car started smoking during throttle lift off period. Plugs looked OK, a little darker than normal but not oily. Turned out guides had approx .050 - .060" clearance due wear so was pretty extreme.

If you find the guides are prematurely worn check the guide material, oil compatability (ZDDP levels), rocker alignment (I am a little wary now of stud mounted rockers as the alignment can vary wildly and needs to be done carefully during installation) etc.

If the guides are worn you may well find the seats need to be recut due to seating misalignment wear. I recut the affected seats and replaced the affected valves and all the springs.

Kel.

[Rich F]

Well I got the leak down test done tonight. I think I've got a ring problem. Low compression in numbers 3 & 4 120 & 130 psi. Others were 190 to 200 psi. Leak down shows leakage in the 60% range in 3 & 4 compared to 10% in others. leaks were throguh the breather not exhuast or intake. I'll give my engine builder the info. tomorrow.
Rich

[Rich F]

Pulled the intake and heads off this afternoon. Pistons 1,3 & 4 were detonating. Have to take the lower end out now and get it to the engine shop. I think it was a timing problem as in too much although I'm not sure.
Looks like I'll be out for a few weeks.

[NZGTRA17]

Originally Posted by Rich F

Pulled the intake and heads off this afternoon. Pistons 1,3 & 4 were detonating. Have to take the lower end out now and get it to the engine shop. I think it was a timing problem as in too much although I'm not sure.
Looks like I'll be out for a few weeks.

Interesting that it was pistons on one side of the engine detonating Rich. Were the tops of the pistons dark/oily or more a whitish ashen colour? Really only a limited number of things could cause detonation this bad;

Timing to advanced
Wrong fuel octane for compression
Mixtures to lean
Leaning out due to fuel surge in bowls
Running to hot on a cylinder head (intake gasket on this head reversed?)
Oil in cylinders lowering octane of fuel
Head on this side been skimmed and compression higher
??
??

The colour of the pistons tops on this side Vs other side will give a few clues.

Kel.

[Rich F]

Not oily but black. Not even completely black. My engine builder seems pretty sure it was timing. the engine is out of the car as of 7:30 tonight. taking the parts over to the engine shop in the morning.
I bought the car from Wirewheel last fall with a "recently freshened" motor. This was my first day running it. Last fall I slid off the track 1/2 lap into my first run and messed up the front end. Day 2 featured the engine puking. Not off to a great start with this thing.
Hopefullly this will be it for big projects on the car for a while.

Rich

[PanozDuke]

Rich,
Bummer. I was hoping it was just valve seals or guides and the bottom end was fine. If it was timing, seems like there should be some evidence of detonation on the other bank as well. Otherwise it could be something with mixture distribution or a combination that became critical on only one side. It is worthy of careful analysis so there is no repeat.

Brian Goldberg (panozracing) has strong feelings about the spec 351W used in the GTS and suffered multiple and frequent failures before building a motor that makes huge power and stays together. Not cheap. If you are going to stay with the stock block and reciprocating assembly, I'd consider limiting the revs, using a main girdle and doing some oiling work to make sure the bottom end gets it's required share. If you can squeeze the budget, go internal balance to take the load off the ends of the crank. I'd also think it would be advisable to run it in on an engine dyno (with the GTS headers) and getting the tune spot on, alternately a chassis dyno. If you aren't pushing it much past 6000 (consistently reving it to 6500 and beyond is destructive on an annual basis) and do a little more to help the bottom end, it should be great for track use. If you are seriously running against Vipers, Porsche GT2's and Z06's, you need to go with the Goldberg solution. Just my $.02 from watching the GTS's run SCCA GT2 here in Texas and reading this forum for the last 15 months.

Mike

[Rich F]

Kel / Mike / Jim

Took the motor to my local engine builder this morning. There was detonation in every cylinder. Just worse on the right side than the left. Fortunately for me he is a Ford specialist. He is going to rebuild the lower end with new pistons, rings and bearings. He may replace rods depending on their condition and type. At his suggestion I agreed to go with a new set of AFR heads, push rods and rocker assembly. (set of used heads for sale cheap) His opinion was that it was caused by timing and likely bad fuel. The motor was used when I bought the car so I really did not know what I had. I'm spending some cash to make it right and hoping I'm going in the right direction.
the clutch looks to be in great shape. i'm going to have a local trans shop have a look inside the gearbox to make sure it's good to go. After all this i really don't wan't any more trouble for a little while.
The photo was taken just before the explosion. No that's not a helmet it's my head....

Thanks for all of your thoughts and feedback. I'll keep you guys posted.

[Rich F]

The engine builder pulled the whole engine apart. I was mistaken on the detonation issue. Only cylinders 3 & 4 had detonation. What I thought was detonation in all cylinders is actually damage to the other piston tops and heads from the 3 & 4 pistons parts blowing all over the intake and into the combustions chambers. According to my engine builder it does not appear to have been caused be timing or fuel quality as we had originally suspected. Seems like those 2 holes were fuel starved. They got pretty hot for sure. Now we are trying to figure out why. The rear float was a little low but not enough to dry things out. I don't have jet extensions on the carb but will add them in case this is part of the problem. I have angled nitrophyl floats front and rear. Fuel pressure was set a 6 psi. Not sure if my gauge is way off and the pressure was a lot higher. Intake manifold is clean and clear. Heads are not bad either. We also looked at the distributor (MSD) to see if any of of the center pick up triggers were bent or broken causing timing to be off in those 2 cylinders. My engine guy is ready to re assemble the motor but concerned that we have not found the real cause of the problem.
Has anybody else experienced this kind of problem with a Carb'd Ford or other power plant?
I'm confused myself but confident that we'll figure it out before we get it back together.
Rich

[NZGTRA17]

Originally Posted by Rich F

The engine builder pulled the whole engine apart. I was mistaken on the detonation issue. Only cylinders 3 & 4 had detonation. What I thought was detonation in all cylinders is actually damage to the other piston tops and heads from the 3 & 4 pistons parts blowing all over the intake and into the combustions chambers. According to my engine builder it does not appear to have been caused be timing or fuel quality as we had originally suspected. Seems like those 2 holes were fuel starved. They got pretty hot for sure. Now we are trying to figure out why. The rear float was a little low but not enough to dry things out. I don't have jet extensions on the carb but will add them in case this is part of the problem. I have angled nitrophyl floats front and rear. Fuel pressure was set a 6 psi. Not sure if my gauge is way off and the pressure was a lot higher. Intake manifold is clean and clear. Heads are not bad either. We also looked at the distributor (MSD) to see if any of of the center pick up triggers were bent or broken causing timing to be off in those 2 cylinders. My engine guy is ready to re assemble the motor but concerned that we have not found the real cause of the problem.
Has anybody else experienced this kind of problem with a Carb'd Ford or other power plant?
I'm confused myself but confident that we'll figure it out before we get it back together.
Rich

Rich, how was head gasket around/between 3 & 4? Ditto for intake gasket in same area? Yes have had the shrapnel effect between cylinders before, makes fault finding a little more difficult.......

The V8 touring car class over here have had engine failures due to G related lean condition. As I recall this was fixed by changing to a different float style.

Are there any plugs missing on the carb? Any rubber plugs that are perished or cracked? No vacuum lines of the manifold? Are the headers OK on these cylinders? No cracks?

How many miles have you put on the car Rich? Could be damage that you have inherited that has then just let go?

Will keep thinking..................

Kel.

[Rich F]

Finally finished up getting the car back together today. Fired up and everything is working and surprisingly no leaks.
Going to try and make a NASA / PDA event this Friday at Pocono.

Thanks to all who helped with support, advice and suggestions along the way.

Rich