Head gasket woes

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Illahe

Mopower
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Gentleman,

I’m running arp head bolts with roughly 11:1 compression at 4700’. Made four passes Saturday at 6200’ adjusted altitude and blew head gaskets on both banks. I bought them from Holley, .053 compressed I believe. Looking for recommendations.

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Fix your tune up. No way you failed TWO head gaskets at the same time in that short of time.

Edit: those gaskets should live forever at that compression ratio.

How much quench do you have? Where is your timing? What plugs and heat range?
 
Newbomb Turk said:
Fix your tune up. No way you failed TWO head gaskets at the same time in that short of time.

Edit: those gaskets should live forever at that compression ratio.

How much quench do you have? Where is your timing? What plugs and heat range?
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Quench is non existent, as I’m running 308 castings with Ross -11cc I believe. Cylinder pressure is 180+ total timing 36*. I’m not versed in heat range. The plugs looked great. Any suggestions on plug heat range would be appreciated.
 
Illahe said:
Quench is non existent, as I’m running 308 castings with Ross -11cc I believe. Cylinder pressure is 180+ total timing 36*. I’m not versed in heat range. The plugs looked great. Any suggestions on plug heat range would be appreciated.
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What plugs are they? Do you have the plug number?

36 total at what RPM? What are you running for fuel?

Take a couple of pictures of a couple of plugs please.
 
Newbomb Turk said:
What plugs are they? Do you have the plug number?

36 total at what RPM? What are you running for fuel?

Take a couple of pictures of a couple of plugs please.
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Quench area is -.010-.015 with the gasket and chamber it’s most likely.1+ oem open chamber iron heads. 91 non ethanol fuel.

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Your heat range is about right because that 63 Autolite is pretty close to a 9 in a Champion so you are good there.

Your idle tune up looks pretty spanky. From what I can see you have too much timing.

You said 36 total but at what RPM??
 
Newbomb Turk said:
Your heat range is about right because that 63 Autolite is pretty close to a 9 in a Champion so you are good there.

Your idle tune up looks pretty spanky. From what I can see you have too much timing.

You said 36 total but at what RPM??
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I’m not sure when total timing is achieved. The oem distributor was recurved by a shop with a sunnen machine. The compression is 1.5pts higher than when I requested the recurve.initial timing is 16*
 
Illahe said:
I’m not sure when total timing is achieved. The oem distributor was recurved by a shop with a sunnen machine. The compression is 1.5pts higher than when I requested the recurve.initial timing is 16*
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It could use less total and probably more initial. It really matters where total timing is.

The good news is it was done on a machine which means it’s probably not locked out which is a bonus.

Do you have your cam numbers??
 
Newbomb Turk said:
It could use less total and probably more initial. It really matters where total timing is.

The good news is it was done on a machine which means it’s probably not locked out which is a bonus.

Do you have your cam numbers??
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I just don’t see much that would make me think you have a detonation issue other than not knowing your exact timing and what the plugs look like at the base.

Those gaskets are better than to fail like that and both at the same time.

I hate to see you buy new gaskets and end up in the same place.
 
Newbomb Turk said:
I just don’t see much that would make me think you have a detonation issue other than not knowing your exact timing and what the plugs look like at the base.

Those gaskets are better than to fail like that and both at the same time.

I hate to see you buy new gaskets and end up in the same place.
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No doubt. I'm wondering if they needed retorquing? I've got some Felpro's for this go round...
 
Newbomb Turk said:
I just don’t see much that would make me think you have a detonation issue other than not knowing your exact timing and what the plugs look like at the base.

Those gaskets are better than to fail like that and both at the same time.

I hate to see you buy new gaskets and end up in the same place.
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I do not see a tan ring on the base of the porcelain. No idea what I should be looking at though.
 
I see nothing jumping out at me by the pictures, nor in what you said you have for timing to cause the failure. Did the gaskets blow in the same spot? For me, I'd question the torque and seating of the heads to the block. I do not know the manufacturer of those head gaskets, so i cannot speak of the quality. I do like Fel Pros.
 
318willrun said:
I see nothing jumping out at me by the pictures, nor in what you said you have for timing to cause the failure. Did the gaskets blow in the same spot? For me, I'd question the torque and seating of the heads to the block. I do not know the manufacturer of those head gaskets, so i cannot speak of the quality. I do like Fel Pros.
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I agree with you. I’m not convinced that the ARP bolts are working. They give inconsistent torque readings as their loading.
 
Illahe said:
The set up is still running the vacuum advance if that helps.
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Ok, vacuum advance. Nothing wrong with that as long as you know when it starts adding timing and how much it adds.

Are you hooked to ported or timed vacuum??

There should be a dark line around the porcelain where it meets the shell. It should be no wider than an eight if an inch.

If you go on Amazon you can order a Dr. Mom otoscope. I think they are 20 bucks. With one of those you can see down in there. Worth every penny.
 
Newbomb Turk said:
Ok, vacuum advance. Nothing wrong with that as long as you know when it starts adding timing and how much it adds.

Are you hooked to ported or timed vacuum??

There should be a dark line around the porcelain where it meets the shell. It should be no wider than an eight if an inch.

If you go on Amazon you can order a Dr. Mom otoscope. I think they are 20 bucks. With one of those you can see down in there. Worth every penny.
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Vacuum is Hooke up above the throttle blades on the metering block.
 
4700' actual elevation? That must be something like 87kPa barometric pressure? So the engine is really only seeing roughly 87% of sea level load even at WOT. (Farmers math - gets you close!)

So that 36* timing is really not that much timing at that load. It's like only partially opening the throttle on a dyno at sea level.
Hard to understand how both head gadgets would let go at that lighter load. Unless the clamp load just wasn't there.

I don't have the answer but just wanted to ask about the altitude/ point this out.
 
Demonx2 said:
4700' actual elevation? That must be something like 87kPa barometric pressure? So the engine is really only seeing roughly 87% of sea level load even at WOT. (Farmers math - gets you close!)

So that 36* timing is really not that much timing at that load. It's like only partially opening the throttle on a dyno at sea level.
Hard to understand how both head gadgets would let go at that lighter load. Unless the clamp load just wasn't there.

I don't have the answer but just wanted to ask about the altitude/ point this out.
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Thank you. I’m at 4700’ and the air at the track went from 6200’-about 7000 by the last pass. I’m not sold on the arp head bolts.
 
Demonx2 said:
4700' actual elevation? That must be something like 87kPa barometric pressure? So the engine is really only seeing roughly 87% of sea level load even at WOT. (Farmers math - gets you close!)

So that 36* timing is really not that much timing at that load. It's like only partially opening the throttle on a dyno at sea level.
Hard to understand how both head gadgets would let go at that lighter load. Unless the clamp load just wasn't there.

I don't have the answer but just wanted to ask about the altitude/ point this out.
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Yeah, I'm thinking something else is going on, as I'd be surprised that detonation did that.

You said its like the clamp load wasn't there, and I think you're on to something. I think 318WR said to verify that the dowel pins aren't holding the head off the deck. That's worth verifying.

I've seen bolt holes that weren't tapped to the bottom and the bolt wouldn't go all the way down because it was bottomed in the threads. That's something to look at as well.

The other thing I keep forgetting to ask is if the block and heads were decked or if one or both were not decked.

Something is wonky.
 
Newbomb Turk said:
Yeah, I'm thinking something else is going on, as I'd be surprised that detonation did that.

You said its like the clamp load wasn't there, and I think you're on to something. I think 318WR said to verify that the dowel pins aren't holding the head off the deck. That's worth verifying.

I've seen bolt holes that weren't tapped to the bottom and the bolt wouldn't go all the way down because it was bottomed in the threads. That's something to look at as well.

The other thing I keep forgetting to ask is if the block and heads were decked or if one or both were not decked.

Something is wonky.
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Heads were decked. I don’t believe the block was.
 
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