81 Scarab project from hell

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05-02-2009, 01:02 AM

#411

DareDevil

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Quote:

Originally Posted by scottie150

But if that was the case- wouldn't it happen all the time? I mean it pops once every 3 or 4 minutes-

Yes,,,could be , all depends on the valve seat ,push rods ,ect. !!

If the valve hangs up it doesn't need to be at every turn of the cam !!

But hey ,,,that's what i think it is ,,,don't beat me to it !!!

And sorry ,because i know thats not what u want to hear !

I would not run like that anymore until u have it figured out . Faster then u think it gets hung up more ( if this is the problem ) and then u slam it on the piston ,valve break's off and ruins the complete block ?!
I would check it !!
Its not that much work !!!

05-03-2009, 10:57 AM

#412

jaxx 30

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Are your spark plug wires in good condition? How are they routed? It could be a cross fire between wires. But hey, I don't have a boat..............

05-03-2009, 11:04 AM

#413

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Quote:

Originally Posted by jaxx 30

Are your spark plug wires in good condition? How are they routed? It could be a cross fire between wires. But hey, I don't have a boat..............

Then it would do it all over the RPM range !!

05-03-2009, 11:39 AM

#414

jaxx 30

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Is this only at idle? Has the engine only been run at idle with only momentary lapses into 3-4K rpm?

05-03-2009, 11:44 AM

#415

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Quote:

Originally Posted by jaxx 30

Is this only at idle? Has the engine only been run at idle with only momentary lapses into 3-4K rpm?

Thats what he said !

05-03-2009, 12:09 PM

#416

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Quote:

Originally Posted by Rookie

Sounds like you have a valve problem. I had the same symptoms when I was breaking rocker studs and also when I had a lifter gain lash and didn't pump up. Pull spark plug wires one at a time until it stops popping to narrow it down to which cylinder bank is having the problem. You might just need to redo the rocker arm adjustment. I forget if you have hydraulic flat tappet or hydraulic roller. If not broke in properly with high moly content additives, I have seen flat tappets wipe out a cam lobe.
Jason

I had the same thing happen with a 400 sbc. I did'nt break anything but I had a "pop" out of #6 cylinder. The pop at idle and also occurred higher up in the rpm range but was on decelleration after I got on it and let off. I readjusted the valves with the engine running and found more power out of #6 and #8 cylinder. The pop went away.

Last edited by jaxx 30; 05-03-2009 at 12:09 PM. Reason: retarded

05-03-2009, 09:38 PM

#417

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Its not the valves. I pulled the valve cover on the right side and then remembered Gen V are non adjustable. I am pulling the plugs next. I will keep you guys in the loop-

05-04-2009, 02:49 PM

#418

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It was a bad plug on #6. Changed all the plugs just to be sure and its good to go!!! Thanks everyone for all the input. Hopefully if the weather cooperates water test this week- I will take pics and video