318 head gaskets and water jacket holes

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solracmopar

solracmopar

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I just installed a set of #302 heads on my stock 318 motor and am having a slight water leak coming out of the rear head bolt area. Not sure if I was supposed to rtv around the water jacket holes on the block before installing the head gasket and heads? When installing the heads I coated the head gaskets with the gold zink stuff and torqued the head bolts at 90ftlb. Was wondering if there's something Im missing? Thanks in advance.
 
Scratch slight. Its coming out like a siv. I pour water in the radiator and it comes out just as fast from the rear of the head. Any ideas would be hugely appreciated. At this point its obvious Im going to have to pull the heads back off..
 
No RTV on the head to block, RTV on the intake to head water jackets.

If it's leaking that bad, I would check for cracks, missing or loose freeze plug also.
 
you might want to check the last exhaust manifold bolt..as the end bolts on the heads go into water...and sometimes leak...which would dribble down onto the rear head bolt area.
 
i had a leak at the rear intake that seep like it was from the head but was not.is water getting to the oil pan.
 
70aarcuda said:
you might want to check the last exhaust manifold bolt..as the end bolts on the heads go into water...and sometimes leak...which would dribble down onto the rear head bolt area.
Click to expand...

That's a good point as well, I didn't think about it as he says it's coming out as fast as he pours it in. Hmmm, I wonder if that stud is there, good thing to check.
 
Bad Sport said:
That's a good point as well, I didn't think about it as he says it's coming out as fast as he pours it in. Hmmm, I wonder if that stud is there, good thing to check.
Click to expand...

my 400 blew the stud clean out....its possible!
 
Guess I can start with pulling out the exhaust to manifold bolts and re- apply rtv those 4 bolts. I never rtv'd the intake bolts. Badsport - do you happen to know which intake to head bolts have water jackets? I'm really hoping I don't have to tear the heads off again. Damn leaks.

On a side note - Thanks for the quick response guys. Having your input sure helps.
 
solracmopar said:
Guess I can start with pulling out the exhaust to manifold bolts and re- apply rtv those 4 bolts. I never rtv'd the intake bolts. Badsport - do you happen to know which intake to head bolts have water jackets? I'm really hoping I don't have to tear the heads off again. Damn leaks.

On a side note - Thanks for the quick response guys. Having your input sure helps.
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I'm not saying RTV the intake bolts, there is a water port front and rear on the intake side of the head, I usually put some kind of RTV sealant on both sides of the intake gasket around those ports. The rear doesn't pass through the intake but is still open into water.

As far as the intake bolts, I usually use Hi Temp thread sealant on those, all of them.

Before you pull the heads, have someone pour while you watch. Check around the rear exhaust manifold stud as Tony mentioned, the front and rear manifold studs go into water and have been known to leak. There should be some Hi Temp thread sealant on those as well.
 
if the leak is still hard to pinpoint after trying that get some UV dye and a blacklight. works like a dream!
 
Scratch that again. I just stuck a pocket mirror near the backside of the head and the freeze plug is clear missing! No wonder water is pouring out of there.. damn.

Ok, while I'm at it do any of you guys know what is the "thinner" head gasket I can use on the heads? I had these #302 heads milled down .30 but when I put the heads on the car I used whatever head gaskets Advanced had available. Since I'm tearing the heads off again I'd like to really maximize the .30 with thinner head gaskets. Also wondering if while I'm at it should I have my machine shop go down another .20? Not sure if it'd be worth it but figured I'd ask. Thanks again!
 
solracmopar said:
Scratch that again. I just stuck a pocket mirror near the backside of the head and the freeze plug is clear missing! No wonder water is pouring out of there.. damn.
Click to expand...

That would be a problem fer sure. Use HI Temp red sealant on the front and rear exhaust manifold studs and ALL of the intake bolts, sometime you can get oil seeping up through the intake bolts, if not sealed.
 
Shave to much off the head and you start having problems with making the inlet manifold match up, then you need to re surface that, then the gasket that runs along the front & back of the manifold won't fit so you have to use gasket goo etc. As long as you are aware
 
mp make an approximately .026 head gasket...

yes..you probably will have problems with the intake sitting down and lining up...

but you can have the intake face of the heads cuts to make the intake fit.
 
Since my intake is lining up rather nicely I might just leave the heads alone. Just have the machine shop put new freeze plugs in. 70aarcuda, who is MP? I'm positive I need that thinner gasket at least.

Here's a pic of the missing freeze plug.
 

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solracmopar said:
Since my intake is lining up rather nicely I might just leave the heads alone. Just have the machine shop put new freeze plugs in. 70aarcuda, who is MP? I'm positive I need that thinner gasket at least.

Here's a pic of the missing freeze plug.
Click to expand...
mopar performance
 
check summitt racing they sell the thin head gaskets I used them on mine
 
You took .030 off a 302? What compression are you looking for as that is going to be pretty high for a stock head. Mill a head and the distance between the opposite intake ports decreases, that makes the intake sit taller, altering the port alignment without milling the intake.
 
pishta said:
You took .030 off a 302? What compression are you looking for as that is going to be pretty high for a stock head. Mill a head and the distance between the opposite intake ports decreases, that makes the intake sit taller, altering the port alignment without milling the intake.
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To be honest I never tested compression before taking off the stock heads. My machine shop did the milling, cut back valves, port matched intake/exhaust and milled the intake itself so that it fit right with the heads.

I just got off the phone with Summit and they are saying these head gaskets are too big for a stock bore. Any ideas? http://www.summitracing.com/parts/mrg-1121g/media/images
 
solracmopar said:
To be honest I never tested compression before taking off the stock heads. My machine shop did the milling, cut back valves, port matched intake/exhaust and milled the intake itself so that it fit right with the heads.

I just got off the phone with Summit and they are saying these head gaskets are too big for a stock bore. Any ideas? http://www.summitracing.com/parts/mrg-1121g/media/images
Click to expand...

I just did some similar work. Mine only were milled .015 and I used the Mr Gasket 1121G head gaskets, about $20 a pop. I had pretty good water leakage from the heads until the car warmed up a bit (I was breaking in a new cam at the time, presumably the leak fixed itself once the gaskets were heated and the teflon stuff or whatever comes on them sealed up). I put thread sealant on all the intake bolts as this engine will leak coolant and oil up thru the bolt threads if you don't. I put sealant on the exhaust bolts and either end of the drivers side but forgot to on the passenger. I think I have a small drip on that side, probably those stupid exhaust bolts.

Anyway, all that with stock pistons my compression calculates to about 8.6.
 
Obviously your freeze plug is still there.....its got a Nice Pinhole rusted through though....
 
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