Author Topic: Exhausted heads?  (Read 1016 times)

Offline Ravage

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Exhausted heads?
« on: May 30, 2016 - 07:32:40 AM »
I took a break from carb. tuning to do some other diagnostics. I'm not wild about the results; I'm wondering how worried I should be. I did a pressure test on every cylinder (image below) and leak down test on the passenger side. Every cylinder tested leaked about 15-20% through the exhaust valves. To confirm the leakage through the exhaust valve I rotated the engine to having the valve open a bit and the sound was the exact same. I rebuilt the engine shortly after buying the car ten years ago. The block was bored 0.60 over (matching pistons acquired), every part on the block was replaced except the crank. The heads only got new springs and valve seals with a lap job done by myself (every valve returned to its original home). I'm thinking the low PSI is due to the exhaust valves. The engine performance has been pretty consistent all these years as best I can tell. Are these numbers in acceptable range? I've been looking at some closed chamber aluminum Edelbrock heads at Summit if it comes to that, but I don't have money to throw around. Thoughts and opinions welcome.

Edit:

 :working: :dunno:


« Last Edit: May 30, 2016 - 07:35:04 AM by Ravage »
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Offline turbostang7

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Re: Exhausted heads?
« Reply #1 on: May 30, 2016 - 07:39:52 AM »
with the lowest being 105 and the highest being 142 the variance percentage is too great IMO. She is tired
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Offline Ravage

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Re: Exhausted heads?
« Reply #2 on: May 30, 2016 - 08:12:33 AM »
with the lowest being 105 and the highest being 142 the variance percentage is too great IMO. She is tired

That seemed pretty odd, I did those cylinders twice to confirm. On the passenger side one spark plug was finger tight and another was out a couple threads. I don't know how it runs as well as it does :P
"I flipped off a box of kittens once..." (Tycho on being evil)

Offline cudabob496

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Re: Exhausted heads?
« Reply #3 on: May 30, 2016 - 08:13:29 AM »
seems a simple valve job would be easy and not too expensive.
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000

Offline Ravage

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Re: Exhausted heads?
« Reply #4 on: May 30, 2016 - 08:30:32 AM »
seems a simple valve job would be easy and not too expensive.

True, I think I'm trying to justify the cost of closed chamber heads. If these heads need to come off this year anyway... I'm curios how much these results are hurting me at the moment.
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Offline Chryco Psycho

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Re: Exhausted heads?
« Reply #5 on: May 30, 2016 - 10:14:54 PM »
I doubt you will see any significant gains with the eddy heads  , they do not flow that much better & often have terrible core shift  , you will lose heat to the alum . How close to deck are the pistons n0w ??

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Offline cudabob496

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Re: Exhausted heads?
« Reply #6 on: May 31, 2016 - 12:38:24 AM »
I doubt you will see any significant gains with the eddy heads  , they do not flow that much better & often have terrible core shift  , you will lose heat to the alum . How close to deck are the pistons n0w ??

How well are my Mopar Stage VI heads supposed to hold up over time?
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000

Offline Ravage

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Re: Exhausted heads?
« Reply #7 on: May 31, 2016 - 05:15:59 AM »
I doubt you will see any significant gains with the eddy heads  , they do not flow that much better & often have terrible core shift  , you will lose heat to the alum . How close to deck are the pistons n0w ??

I have no idea I'm afraid. I didn't have the block decked and the pistons are basic flat-tops. My brother planted the seed in my head that for little more than twice the price of eddy heads I could get a 408 stroker. Now I'm evaluating the possibility of driving it 'till it dies, saving money and dropping a crate motor in.
« Last Edit: May 31, 2016 - 05:20:18 AM by Ravage »
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Offline Chryco Psycho

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Re: Exhausted heads?
« Reply #8 on: May 31, 2016 - 08:05:53 PM »
once you open the can of worms for just a few more $$ .....
the 308 head option is a great one for a few $$ freshen a set , port them & 41 RWHP is there right now !
 

Challenger - You`ll wish You Hadn`t