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Discussion Starter #1
I have a friend that is building a cobra but is not a frequent flyer on this forum. He had his 302 rebuilt as stock. Car is not on the road yet. It has run no more than 20 minutes. It is EFI. He lost compression in ALL cylinders. The builder calimed that he washed the rings out by running too rich or there was a problem with his FI system. Is this even possible with FI?

Thanks for the help!

Dennis
 

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The only way I know of that you lose compression in all cylinders suddenly is if the timing chain breaks or some other such malady such as the cam sproket drive pin shearing.. This will cause a lot of other trouble inside the engine such as bent valves, etc..

Cylinder wash-down is a real problem, but it won't kill and engine that fast. Yes an EFI engine can wash them down, but you would typically have some codes set in the ECU.
 

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Hi Dennis,
Sounds very unlikely. It has no compression? Could it be the lifters/rockers are adjusted to tight? Need more info but if he just started it and has no power thats where I'd be looking. If it has bolt down rockers just losten them 1 turn each and turn the engine over again. I'd think compression will return and just need a rocker shim kit to fix the problem for good. I have the shim kit in stock if you need it. Call me with any questions.
Mike Forte
781-248-8946
 

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Hi Dennis,
It is possible on a FE if the lifter preload is to tight. It can happen on any engine if the valves are to tight. That's why I like mechanical adjustable rocker arms.
Mike Forte
 

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Darn it Mike - Good point on the pedastal shims! :D
 

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This is why I love this place!!
Where else can you get folks like Mike and Randy to take the time to Root Cause your problem?
Keep at it Dennis, I'll be looking to see how it goes.
 

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Dennis did your engine builder tell you "You needed to replace your muffler bearings also?" If washdown is the proplem just pull the plugs and squirt some oil into each cylinder and turn the engine over with the starter to spread the oil around in the cylinders. I would do a LEAK-DOWND test to see where your compression is going. Randy and Mike are at the most probable cause . If you engine run at all the WASH-DOWN story is hard to go with. Do the LEAK-DOWN test and you will know if it's the valve train or a cylinder problem. What does you engine person do for a living? Work for a FORD Dealer.
 

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If you need those muffler bearings.....well I got out of that business.

I think the lifter preload is a possibility, but you would have to improperly set preload on all of them for compression to be down on all the cylinders. I suppose if you carefully followed an incorrect preload adjustment procedure, this could be possible.

What was your oil pressure by the way?

How are you checking compression - like how many times are you turning over the motor?

I would definitely shoot some oil in a spark plug hole or two and see if it changes. If a couple of shots of oil does nothing, then then the rings are almost certainly not the problem.
 

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Hi Randy,
I thought of the timing gear bolt getting loose and then remembered the timing cover would interfer and the noises would have been another telltale. I remember a Ford dealer tech saying that the Ford roller rockers were defective because the engine lost compression after installation. He also said the interfered with the valve covers and they shouldn't being made by Ford. The customered towed his car with his AAA and I had it fixed in under 45 mins. The tech never heard of shims before. I'm glad he hasn't worked on any of my car!!!!
Mike Forte
 

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I talked to the owner at great length on the phone yesterday. the engine is already apart for inspection. Soemthing went wrong in all cylinders causing the cylinder walls to be polished to a shine. Also the oil was very dirty suggesting possible iron in it. It did not smell like gas though which I think it would if that much gas was being dumped. Also the owner stated that it ran fine with no black smoke. Once he shut it off it would not restart. He put oil in the cylinders to get the compression back up and was able to start it.
He also told me they were running it with no o2 sensors. Bad news, but it probably barely made it into closed loop in 20 minutes. It my understanding that the o2 sensors dont do anything in open loop.
 

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Is it possible that the re-builder didn't get the cylinders sqeaky clean after honing? After final honing the cylinders get washed out and dried before reassembly. Many years ago a racing / engine builer buddy wised me up to an often overlooked final step. Namely wiping down the cylinders with clean paper towels saturated with alcohol. A cylinder that looked spotless and felt clean to the touch turned the paper towels black. Without that final wipe down, the leftover grit trapped in the cross hatching goes to work on the cylinders and rings and will kill compression. Just a thought.
Frank
 

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Originally posted by Frank Messina:
Is it possible that the re-builder didn't get the cylinders sqeaky clean after honing? After final honing the cylinders get washed out and dried before reassembly. Many years ago a racing / engine builer buddy wised me up to an often overlooked final step. Namely wiping down the cylinders with clean paper towels saturated with alcohol. A cylinder that looked spotless and felt clean to the touch turned the paper towels black. Without that final wipe down, the leftover grit trapped in the cross hatching goes to work on the cylinders and rings and will kill compression. Just a thought.
Frank
I usually hit a block with the pressure washer using hot soapy water after any cylinder boring/honing operations. I then blow it dry and wipe any machined surface with oil. This will loosen and wash away any hone and iron debris that may have been deposited in the cross hatch in the cylinder.
 

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Like I said, it's just a thought. We we're building race motors with a 2% leakdown rate and standard gap rings though, so no stone was left unturned to insure a good seal. YMMV
Frank
 

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Discussion Starter #14
Mike Everson... I guess were talking about the same guy... Anthony. Anyway, whats hard to beleive is that the builder rebuilds engines for Dyson racing in Poughkeepsie NY. The builder is accepting responcibility for it. I guess at this point we'll never really know.

Thanks Everyone!

Dennis
 

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Originally posted by Michael Everson:
I talked to the owner at great length on the phone yesterday. the engine is already apart for inspection. Soemthing went wrong in all cylinders causing the cylinder walls to be polished to a shine. Also the oil was very dirty suggesting possible iron in it. It did not smell like gas though which I think it would if that much gas was being dumped. Also the owner stated that it ran fine with no black smoke. Once he shut it off it would not restart. He put oil in the cylinders to get the compression back up and was able to start it.
He also told me they were running it with no o2 sensors. Bad news, but it probably barely made it into closed loop in 20 minutes. It my understanding that the o2 sensors dont do anything in open loop.
Wow....

Could it possibly be that the rings were file-fit and were not gapped properly? If they had less than .010" gap, they would expand to the point where they will bind and literally tear the cylinder wall cross-hatching out. Most likely resulting in cylinder walls that appeared to be polished.. Rings get REALLY hot in the first 20 minutes of operation until they break-in..
 

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If all the cylinders went bad at the same time,you may want to check your cam timing.
I'll bet your timing chain jumped a tooth or two.
 

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Just my two cents. I had a Ford 460 rebuilt with EFI and it washed the cyliders out, but it still ran after 500 miles. The problem was that the timing chain and sprockets were off from the manufacture so the engine would not develope enough vacumn for the computer(only 8") so it overcompinsated with addition fuel. The motor was torn down and rebuilt again and ran perfect after that.
 

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Thanks gentleman for all your great in site.I think the consciences of option is a builder error? He's doing the right thing by me but I would really like to make sure it's not a fuel wash down.What's the best thing for me to do to make sure it's not fuel? Would having him Dyno the engine be a good idea?

Thank you
Anthony
 
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