Do I have a bad head gasket?

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73smallblock

73smallblock

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SO getting the car read because the track is finally opening and going over a few things and keep building pressure in the radiator. Car sat all winter without water in it. I had changed the oil (vr1) first and it looked a little tan in color, didn't get any water out when i drained the oil so i just chalked it up to moisture from sitting all winter, open headers with vac-u-pan. Ran the car up to temp and let it cool down. Take the rad cap off to check the water level and as soon as I get to the first release of the cap water starts to push out like it does when its hot and you try to take the cap off. Get to the full release of the cap and its gushing out.

Tried refilling it with the water pump turned on, fill it till its full. Start it again, bring it up to temp, let it cool back down, same result. I have tried this a few times, always the same result. No water appears to be in the oil, it still looks new and the level has not gone up. I've tried filling it with the front of the car way high thinking its an air pocket, but the same result.

Is it possible that I have compression leaking into the water somewhere making it build pressure but not mix water and oil? I pill the breathers and see a touch of moisture on the baffle in the valve cover, again just accounting it to sitting.

Engine specs
360 La - .060 over
4'' eagle crank
eagle rods - icon pistons
.590 mopar cam solid/flat
speedmaster heads - m1 intake
11.8 compression
head gaskets are felpro performance 1008
 
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"with on water in it"? I assume you meant "with only water", and not "with out water"? If so, and JMO, you're lucky if it is just a head gasket. Leave the cap off and fire up the engine, look in the rad- if it's pushing a steady stream of bubbles, you've got a compression leak somewhere. Run a compression test to localize the issue. Could be multiple points. Depending what the compression test tells you and where, that's the head you pull and inspect... could be gasket, cracked head or cylinder...
And now you know why you don't store it without antifreeze or draining it... :(
 
I meant without water in it, edited post. Where it sits in winter, its not heated. I will try the compression test. At one point with the engine off and cold I do recall seeing a some tiny bubbles working out and making some noise. It's hard to see when it runs because of the car shakes so much but I will try that as well.
 
Gotcha. Sounds like a plan, and hopefully it's not anything major. Head gaskets are a pain, but not as bad as something cracked. I'll keep my fingers crossed for ya, and keep us posted!
 
Another test is to pressurize the cooling system, and see if it holds pressure or pumps coolant into a chamber. If the system does not hold pressure and you cannot find an external leak: DO NOT CRANK the engine over; instead pull the spark plugs all out. Water is not compressible and leads to bent rods.
Now you can bump-start the crank and see where the coolant is going.

IMO, the radcap should be venting.
Maybe you just have a faulty thermostat?
 
Car doesn't have a t-stat in it. One thing I did try was pulling the plugs and cranking it to see if any water misted out, it did not. I just have personally had a bad head gasket where the fluids did not mix. Just trying to get some opinions other then my own.
 
This was something I learned when I wrenched on cars. No T-stat and put air into each cylinder just like leaking a motor down and look in the radiator. Bubbles will be present and a backdoor way of pressure testing. I did this when I suspected a head gasket but the usual techniques weren't working. Just something else to try if you suspect a leakage and easy to test....

JW
 
Well just turning the engine by hand I could see air bubbles coming up through the radiator. Pulled the heads and nothing stands out but I still think it's the problem. I figure if it's not bad enough to have fluids mix it may not be bad enough to see by eye. So new cometic gaskets are on the way and also some new trick flow heads. I wanted to upgrade to them this upcoming winter and figured now would be a good time. What type of sealant do you spray the head gaskets with? I can't recall what it's called.
 
Well new heads and gaskets are installed. Need even longer pushrods then the ones I had, so I had to call Smith brothers. It was my first time dealing with them and couldn't be more happy with my purchase. Anyway the problem seems to be fixed. I will see what it runs next weekend, weather permitting.
 
Great. Did u have the block and heads surfaced to the RA value that Cometic gaskets need. If not that is ur problem that will surely re appear. What rockers are u using. Kim
 
I have never heard of cometic gaskets requiring an certain RA to seal correctly. This is also my first time using them. The block was decked less then a year ago and still looked good. I probably should have had the speedmasters checked for straightness before putting them on. I also don't really think the fel pro gaskets I used have a whole bunch of crush to help I'd the head was out a few.
 
Oh and I am running Mancini rocker arms that they advertise as Harland Sharpe. The wipe pattern was just above center.
 
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