Found my problem! Now tell me how it happened!

[Black Power]

My Gn was running HORRIBLE! A compression test told me that #4 was substantially lower than the other 5. I yank the heads off and wham! All 6 intake valves kissed the pistons and left an eyebrow. Apparently #4 hit hard and it bent the valve.

Now....why?

Here is my combo:

4.1 NA motor - hasn't been decked
.30 over stock pistons (dish like a gn's)
stock crank
8445 heads with stock valves (I think, I am gonna measure tomorrow)
Felpro blue head gaskets
212 flat tappet cam, stock replacement lifters and stock pushrods. Nonadjustable valvetrain.

I am 99% sure I never overrevved this thing.

Here is what I am guessing: Either the timing is a tooth off, or the intake valve is big, or I got sent a bigger cam than I wanted.

Anything I am missing here? I am pulling the front cover tomorrow to check the timing.

I have to make sure I get this thing right because October is coming soon and I have Fords to kill!

Also, I have a set of Champion aluminums on the way, how will those work out compared to the 8445 heads as far as PTV clearance?

 

[Nick Micale]

Was the cam degreed during install?

I would agree the timing chain could be a tooth off. As for valve size in an iron head, it can only accept a very slightly larger valve, and probably not the issue.

We have received cams that have been ground with lots of advance or retard which could be a culprit?

Even if you over revved the engine, this should not happen - been there before with no damage.

If the heads were done and ALL the intake guides too tight would be a long shot, but possible. Never had all 6 seize, but seen 2 or 3.

How long has this cam/engine been run or driven?

 

[Black Power]

Was the cam degreed during install?

I would agree the timing chain could be a tooth off. As for valve size in an iron head, it can only accept a very slightly larger valve, and probably not the issue.

We have received cams that have been ground with lots of advance or retard which could be a culprit?

Even if you over revved the engine, this should not happen - been there before with no damage.

If the heads were done and ALL the intake guides too tight would be a long shot, but possible. Never had all 6 seize, but seen 2 or 3.

How long has this cam/engine been run or driven?

Cam was installed straight up. I wondered about maybe getting a cam that was ground goofy.

A buddy of mine overrevved his 427 the other day (missed a gear) and tagged all 8 pistons, that's why that came to my mind.

This motor has probably 1k miles on it, but it never ran good.

 

[Chuck Leeper]

"but it never ran good."
The cam is in at some other than "straight up" position...
You didn't answer Nick's ?? Was it degreed in?????

 

[TurboBuRick]

Being that it never ran good, I would suspect cam timing.

 

[Mike Licht]

there is only two things that can cause that since the cam does not have enough lift for there to be a problem. Either the valve springs we so weak that valves floated but that is doubtful since it is so mild or the cam was installed incorrectly. Just putting it in "straight up" is not a replacemt for checking it with a wheel.

 

[Black Power]

"but it never ran good."
The cam is in at some other than "straight up" position...
You didn't answer Nick's ?? Was it degreed in?????

No, it wasn't. I don't have a wheel.

Being that it never ran good, I would suspect cam timing.

10-4. I'm pulling the front cover today.

there is only two things that can cause that since the cam does not have enough lift for there to be a problem. Either the valve springs we so weak that valves floated but that is doubtful since it is so mild or the cam was installed incorrectly. Just putting it in "straight up" is not a replacemt for checking it with a wheel.

IIRC it has LT1 springs on it. I will do some checking today.

Thanks for the info guys. I've got to get to the bottom of this and soon :biggrin:

 

[mike lee]

bent valves

HAPPENED TO ME ABOUT TEN YEARS AGO ENGINE BUILDER DID NOT HAVE TIMING CHAIN SET RIGHT BENT ALL INTAKE VALVES AND EYEBROWED 6 BRAND NEW JE PISTONS PLUS BEND PUSH RODS AS AN ADDED BONUS HE BOUGHT ME ALL NEW PARTS AND I ASSEMBLED ENGINE MY SELF HAD NO PROBLEMS GO FIGURE