Help!! We fired up my freshly rebuilt 427/425, broke it in (engine sounded incredible), and drove it for about ten miles. Toward the end it wasn't running too well so the mechanic wanted me to pull over so he could adjust the timing (no back firing). Well, while messing with the distro he killed it. It refused to restart. I checked the forum and found the hot restart problem thread. So I go back the next day. The car fired right up but soon started back firing through the carb. We pulled the valve covers and 6 rockers on one side and 3 on the other are ridiculously loose. We tried to adjust them but something was just not right. There is metal dust in the oil that is standing in the head. We shine a light down to the lifters (I went back with hydraulic cam and lifters under advisement on drivability) and saw that some are collapsed. After pulling the intake off, we discovered many collasped lifters and some bent rods. We haven't pulled the engine and cam yet but you can kind of see it and the mechanic says he thinks it is wiped. Has this happened to any of you before? Thank you Bill#44207
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did the cam have the groove in it?
1965 and 1966 cams had a groove in the rear journal to supply oil to the lifters. Most replacement cams do NOT have this - you have to ask for the grinder to add it. Since it's a 425 HP engine, I am assuming it's an original 1966 block.
Hope this helps,
Mark -
Re: did the cam have the groove in it?
Mark, this will be the third time the engine has been rebuilt. The first time I dropped a valve and 2nd time the oil groove was not there. We smoked the driver side bank. Then I insisted that the mill a groove in the cam. They didn't want to and said that we did not properly prime the engine. No oiling problem this time. Thanks Mark. BillComment
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Re: did the cam have the groove in it?
Bill,
Don't have the answer but remembered reading something on this subject. The source is the Chevrolet Power Service Manual, dated 1975. It was a publication of General Motors and I quote:
"In the event you use a camshaft which has a groove in the rear camshaft journal, remove the rear camshaft bearing, solder up the oil hole and redrill it to .060" dia. A grooved rear journal was required for valve lifter oiling in 1965-66, but creates a major internal oil leak in later engines which can affect oiling system performance."
What vintage is your block?
Feel your pain.
MyronComment
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did you fill the hyd lifters with oil before
installing them? you should never do that because you can not get the pushrod seat to move down. hyd lifters should be adjusted cold with the intake off so you can see the pushrod seat moving down about .020 when you adjust the valves.Comment
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Re: C2 fresh 427 wiped cam? Serious problems, Help
Bill,
I have a feeling you may be having left over problems from the last time the engine ran with no oil to one bank of lifters and rocker arms. It doesn't take long to destroy a new cam and lifters with little or no oil and judging by the amount of lash some of the valves now have, I would guess this is exactly what happened. The fine metallic particles that you mention may be from the cam and lifters?
I usually try not to place blame for things like this but in my opinion, it's definitely time to find an engine builder that knows what he's doing. This whole adventure has been one failure after another, and for reasons that should not have been.
The mismatched cam and rear cam bearing should be common knowledge to an experienced builder. I think this is where all the trouble started.
Also, if the engine builder gave you a complete engine back, the valves should have been set properly. It's possible to make this adjustment and get it VERY close with either mech or hyd lifters while the engine is still on the engine stand.
Unfortunately, there's no way to remove all of the fine metallic particles from inside the engine and it's components without completely disassembling the engine again. You may find other "issues" inside from the metal that's floating around in there.Comment
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Re: did the cam have the groove in it?
Myron, the block is original to the car. Thanks for the info. I will pass it to the next engine builder. BillComment
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Re: did you fill the hyd lifters with oil before
Clem, I didn't do anything. I am far from a mechanic. I left that to "the experts." Some experts.Comment
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Re: C2 fresh 427 wiped cam? Serious problems, Help
Michael,
If this happened before ( in one way or another ), is it possible there is
a partial blockage in one of the oil galleys? I would imaging that restricted
oil flow would cause an almost immediate demise of the cam. Remember what we
learned last week about the springs getting cherry red after 30 seconds with
no oil?
This is one of those scenarios that scare me! You do everything right, but
come up short. These engines are too valuable for this type of problem.
Bill, were the core plugs all removed when the engine was cleaned?
Is there a way to snake through all the oil passages to check for
obstructions? Can the oil galleys be pressure tested prior to assembly?
Just some thoughts?
SteveComment
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