I have a 800 mile roller 355. Trick Flow G1 heads. 10.5:1 compression. Had it all machined and assembled by a local machinist...

From day one Ive had condensation in my valve covers, and a big loss of coolant. Nothing out the tailpipes, nothing in the oil, nothing in the cylinders. Real weird problem.

I replaced the intake gaskets, and had the intake checked. Didnt fix the problem. Compression check showed 160psi in cylinders #1 and #3, all the others were 180-190. Figured bad head gasket.

Pulled the heads and had them checked today. They are fine. Head gaskets looked ok too. Head gaskets are ROL brand. Not the best, but figured they would work.

I have to check the deck with a straight edge to make sure the block isnt warped. Assuming the block is fine, has ANYONE here ever heard of a head gasket that just didnt seal properly?

Leak down test on the radiator went from 15 psi to 13 psi in about 25-30 minutes....real slow.

Im lost!

 

Sounds more like your radiator cap isnt holding the proper pressure... try a 10 dollar or less radiator cap (check your current cap for correct pressure to get) and try that.

 

Already replaced it. Also when I have the pressure tester on the radiator with the car running, it reads up to 25psi in the cooling system like compression from the engine was leaking in.

 

Stupid question, but did you remember sealant on the threads of the head bolts?

 

yup

 

aluminum heads? i'd guess you used a gasket not made for aluminum to iron block

 

Weren't you getting 20+psi reading from the coolant system while the engine was running? IIRC you forgot that in another post I replied to

You probably need a leakdown test as well, but from all indications that you've posted here and before, I'd have to lean towards a cracked head. Get it checked. Just don't let a shop tell you they'll 'magnaflux' it for you.

 

yeah RD, look above. I stated that I was getting a LOT of PSI in the coolant. Heads checked out fine yesterday. I decided today that the block is going to the machine shop monday to get tested. If all goes well, it should be done friday, again

 

Aside from using the proper head gaskets, another secret is using Barr's leak or some sort of stop leak when installing everything. I've heard this from more than one shop and alot of racers running aluminum heads, even when properly built the heads expand and contract so retorqueing is necesarry after some run cycles-mine heads took about 1/2-3/4 turn more per bolt after some run time to get back into proper specs.

What made me check was I was also losing coolant somewhere and had no idea where. First thing I did was retorque all head bolts, then before I fired it up I dropped in a bottle of Barr's leak...that was last year and no more missing coolant...go figure.

Many racers that build their own engines have all said the same thing about pulling head gaskets and finding areas where the stop leak compound had filled in tiny voids around the steel ring in the head gasket.

Hopefully it's something major you find to justify a complete tear down

 

well, i know it sounds dumb, but did you clean the block and heads extremely well, like glass smooth well... i used some ****ty cheap head gaskets that i got from summit on my 383 build about 3 weeks ago and i started the car and had problems instantly... i didn't even get 1 minute run time on the brand new motor and i had to tear it all apart again. ended up spending the $50 for the good felpro-self-sealing head gaskets and haven't had a problem since... i not only noticed a drop in pressure on mine though but when i took the spark plugs out of cylinders 2 and 6 i seen water condensation inside the plugs....

 

I had instant problems with my motor too. Noticed condensation in the valve covers when I took them off to adjust the rockers.


Reason I am tearing the motor down, is to find out if there IS a problem with the block. If there is, and I put the heads back on, im gonna be real pissed.

 

Did'nt they test the block prior to machining to see if it was even worth building or to see necessary steps that may be needed to use block?

I always get condensation under my valve covers (cast aluminum) more so if I don't let motor get to operating temps for awhile to burn off some of the moisture. Day before races I take the car out for a good 30minute driver to get everything good'n hot then come back to check lash adjustiment. Not once last year or now this year have I ever pulled covers and not had condensation on the stud girdle/under side of cover. I just chaulk it upto the aluminum disappating heat at a different rate than everything else under the hood. Kind of like how aluminum windows attract moisture in wet/humid climates.

 

I TOLD them to check the block and he said he did...who knows


and by condensation, I mean milky white like a bad head gasket.

 

I agree with IHI on using a stop leak, but I don't like Barr's. I have seen it partially clog a few radiators, and heater cores. I would use 2 of GM's cooling system tabs. They come in a pack of 6 for like 10.00. I used them on mine. I used the .015 Fel-Pro steel shim gaskets and was worried they would leak. So far so good.

 

well, I know its been almost a month, but...

I heard from the machine shop the other week. The head gasket was indeed bad, even though it looked fine. Absolutely everything else checked out 100% fine.

Learning experience #3998453