looking for a little engine help again

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Mar 19, 2007 | 10:12 PM

panchop

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Melting Slicks

Joined: Dec 2000

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From: mesa,az

looking for a little engine help again

built a little 327 for my 65 vette. Forged SJ crank, scat I beam rods, 11-1 TRW pistons, probe 1.6 shaft rockers, lunati solid flat tappet cam. 292 heads with 2.05/ 1.6 valves. I degreed everything, checked P/V clearance etc.... Ran the engine about an hour on my test stand. everything fine. I put a couple hundred easy miles on it yesterday. today I dropped the hammer a couple times, shifting at 6800 RPM etc. i pulled of the highway and the idle wasn't right. drove a mile and realized the engine was getting hot. popped the hood and i had thrown the belt. easy fix but now The passenger side pipe has a flat pop, like I have a dead cylinder or something. pulled the plugs and the all look the same. whats my next diagnostic step.

Mar 19, 2007 | 10:23 PM

big_G

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From: Austin Texas

Check for a burned plug wire, then check for a flat cam lobe or other cam related failure.

Mar 19, 2007 | 10:34 PM

coinwasher

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From: Glen Allen (Richmond) Virginia

How hot did it get? Head gasket or valvetrain? I would pull the valve cover and watch the rocker action on free spin, if that is OK I would go for the compression check.

Mar 19, 2007 | 11:28 PM

panchop

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Melting Slicks

Joined: Dec 2000

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From: mesa,az

well compression is all the same across the bank. 180 # within a # or 2. I did find that a wire had come off the alternator but i don't see how that would account for the sound. I will pull the valve covers and take a look in the AM. the plug wires look good.Because I have no patience I pulled the valve cover tonight. nothing jumps out at me.

Last edited by panchop; Mar 19, 2007 at 11:39 PM.

Mar 20, 2007 | 01:31 AM

cardo0

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Joined: Oct 2002

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From: Las Vegas - Just stop perpetuating myths please.

Try a leak down test next to verify all good cylinders. It all cyl's still good then its an ignition or fuel problem.

BTW a wiped cam lobe should increase compression in that cyl - but maybe had to see if all new cyl's and lobe not completely wiped.

Good luck.
cardo0

Mar 20, 2007 | 08:14 AM

hugie82

Safety Car

Joined: Mar 2007

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From: Bridgewater nj

go to the basics, Like the other guys said. Look for spark (check plug),check compression and then check the (all to common) cam lobe by lifting the valve cover and watching the rockers (its usaully odvious)If the rockers are moving try a minor adjustment and see if it makes a differents.I hate to sound like doom & gloom but what kind of oil did you use for breakin?

Mar 21, 2007 | 08:14 PM

coinwasher

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From: Glen Allen (Richmond) Virginia

Any new newa on this one?

Mar 22, 2007 | 12:40 AM

panchop

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Melting Slicks

Joined: Dec 2000

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From: mesa,az

OK lash is good, no bent push rods. i found a cracked plug but I think I did it taking it out. Anyhow. i put it back together and start it again. sounds good. I back up the timing a little to about 12-13 initial. as the car heats up i start hearing the sound again. When it's cold the engine is noisy as hell, forged everything solid lifter motor so no surprise. I lay down next to the pipe to listen to it. now I'm running about 11-1 on 110 octain gas so every pop is a loud one. every once in a while it's just different. got me thinking. I bolted the cast iron manifolds straight on to the heads with no gasket, first time i heard this noise is after i threw a belt and the motor got hot, not killed it hot, about 220 hot. Chevy originally sold them with manifold to head without a gasket but my manifolds came from china. i wonder if i just have a little air getting in there and exploding. on the other hand i am still running a little lean so it may be wishful thinking.
PS as i am typing i am also thinking , i had a vibration problem from the fan clutch. on this car the alternator is mounted to the passenger side exhaust manifold....