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Premium Member
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Yeah, you blew a head gasket. It had to run like shit while that was happening. It doesn't take long, but longer on a iron head than a alum.
I'd find it hard to believe that the block isn't in need some machining. If you don't, it can very well happen again, FAST!

Cause?
No machining on the block and heads that needed it
Inferior machining
Cheap rebuilder gasket
Detonation due to tune. 10.2 to 1 with iron heads and the load of a boat requires the tune to be pretty spot on.



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Some guy
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Things I would look at are dome volume of pistons, verify TDC and timing pointer, and quality of fuel, along with engine temperature. The block doesn't show any damage?

I had someone do that to one of my street engines one time, but they admitted pulling a trailer through the desert at speeds up to 120 mph, noticing the engine temperature getting "warm", but continuing to run. I also suspect they might have been messing with ignition timing as they used to do crazy stuff with the 3/4 ton Suburban the engine was in.
 

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Discussion Starter #4 (Edited)
The engine never went past 180 and was only at that for maybe 30 sec.
Not sure of the machining
8523pti on the gasket
20 cc dome Volume
engine was very fat with 93/95 jets then went to 85/88 s in a 830 Holley plugs never appeared lean.
The timing indicated 28 then I bumped it to 32
Never got over 5200
cam Flat Hyd 306/240/544 112 sep. Square
Log exhaust
I will check the block

Another pleasure boat. I feel like a heroin addict.
Time for Alum. Heads. Any suggestions?

Thanks for the help guys
Tom
 

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Premium Member
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I pretty much recognized the gasket from the picture. Read the description.

LINK Fel-Pro 8523PT-1 Fel-Pro Cylinder Head Gaskets - Free Shipping on All Orders @ JEGS

LINK http://www.summitracing.com/parts/FEL-8523PT-1/

Compared to:
LINK http://www.summitracing.com/parts/fel-1037/overview/make/chevrolet

There is a reason the cost twice as much.
It could have been worse. It could have been a $15.00 8180 PT2

Less than perfect decking, at that compression, with that gasket is certain failure. You get a machinist pushing the fly cutter on too much angle and it leaves a low area right down the center of the head and or block.

With that compression, and iron heads, you have to give the engine a fighting chance by having everything PERFECT.
Tune, machining, and materials. It didn't take much to blow that particular gasket out between the cylinders.



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Living in a cage of fear
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I pretty much recognized the gasket from the picture. Read the description.

LINK Fel-Pro 8523PT-1 Fel-Pro Cylinder Head Gaskets - Free Shipping on All Orders @ JEGS

LINK http://www.summitracing.com/parts/FEL-8523PT-1/

Compared to:
LINK http://www.summitracing.com/parts/fel-1037/overview/make/chevrolet

There is a reason the cost twice as much.
It could have been worse. It could have been a $15.00 8180 PT2

Less than perfect decking, at that compression, with that gasket is certain failure. You get a machinist pushing the fly cutter on too much angle and it leaves a low area right down the center of the head and or block.

With that compression, and iron heads, you have to give the engine a fighting chance by having everything PERFECT.
Tune, machining, and materials. It didn't take much to blow that particular gasket out between the cylinders.
Gotta go with Bob on this one, especially looking at the lack of gasket imprint on the other chamber on the right.
In fact, the gasket imprint in the damaged area doesn't really look that bad considering the ditch that it cut.
Almost as if it was a previously repair that failed?
 

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steelcomp was here
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26,528 Posts
Pig fat and timing only at 32? My guess is your egt's were sky high. That didn't help the situation at all.
 

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steelcomp was here
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496 10.2 /1 with second hand 990s
Three hours on the engine
Total timing 32. Pistons look good.
Any ideas how this happened?
Did you clean the quench pad on that one chamber, or did it come off the engine like that?
 

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The engine never went past 180 and was only at that for maybe 30 sec.
Not sure of the machining
8523pti on the gasket
20 cc dome Volume
engine was very fat with 93/95 jets then went to 85/88 s in a 830 Holley plugs never appeared lean.
The timing indicated 28 then I bumped it to 32
Never got over 5200
cam Flat Hyd 306/240/544 112 sep. Square
Log exhaust
I will check the block

Another pleasure boat. I feel like a heroin addict.
Time for Alum. Heads. Any suggestions?

Thanks for the help guys
Tom
My suggestions
Listen what Bob is pointing out.
Decision time,
I would give Barry 001 a call and ask for a little help sorting it out.
Make a appointment to bring it over.

Barry, has a machinist eye for detail, let him look it over.
Then he can tell you the good and the bad news.

The newbie Scott Foxwell is in the head business I would go with a proven product and use Steel comp :shhh:
 

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steelcomp was here
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26,528 Posts
My suggestions
Listen what Bob is pointing out.
Decision time,
I would give Barry 001 a call and ask for a little help sorting it out.
Make a appointment to bring it over.

Barry, has a machinist eye for detail, let him look it over.
Then he can tell you the good and the bad news.

The newbie Scott Foxwell is in the head business I would go with a proven product and use Steel comp :shhh:
:rolleyes:
 

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Discussion Starter #13
Did you clean the quench pad on that one chamber, or did it come off the engine like that?

Nothing was cleaned. First order of business is to determine the condition of the block.
If I get lucky then it is Aluminum head time. That is why I was reaching out for suggestions.
If I am unlucky then it is rebuild time.
My objective was and is a pump gas 496 that will be turn key low drama. 6000 rpm with low end and midrange power.
Thanks guys for contributing to the thread.
 

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What's the other side look like? I saw one at a buddy shop had the coolant restricted on one side, about the time the temp gauge went 190 it was already loosing power. It torched the head as bad as that one and the block too. The other side looked just like a motor with less that 2 hrs.
 

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Discussion Starter #15
What's the other side look like? I saw one at a buddy shop had the coolant restricted on one side, about the time the temp gauge went 190 it was already loosing power. It torched the head as bad as that one and the block too. The other side looked just like a motor with less that 2 hrs.

Have not removed that head yet. 210 compression in 6 holes
 

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Discussion Starter #17
I got lucky.
The block is flat. Now I need heads.
Are the Edelbrock 61559s good?
I have a Airgap manifold but can replace.
306/240/544 flat tap. Hyd
Harman Log exh.

Down the road,I could change the cam to solid roller and have some head work done.
I am stuck with the exhaust.
Any suggestions are appreciated.
 

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Vastly better than the 990s, and the aluminum will help you deal with the compression much better. You were pushing it with the iron heads.
LOT of duration for a log exhaust. You need to be carefull where the water entire the exhaust or you could see some reversion.
The logs would like to see more duration on the exhaust side compared to the intake. Looks like you are saying you have 306/240 intake and exhaust.

DO NOT USE THE SAME HEAD GASKET!!!!



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No one mentioned, so I will....

DO NOT USE THE SAME HEAD GASKET!!!!
In addition to this idea, I'll add not to use the same head fasteners. With those stocker gaskets the stocker bolts, (if used), never gave it a chance.... Even if you had/have ARP studs, replace them...

OH, AND check the block threads to torque # under a load. I use a block of steel, (6"X2"X1") to check the threads prior to trying to assemble only to find a thread or two, (or more) pulled out. The steel block with a hole in it is a lot easier and gives you a chance to fix the threads before setting the heads on...
Ray
PS the Aluminum heads probably will require a fastener change anyway...
 
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