beenba

I will try and keep this short.

I built a ERL sleeved B18c last year - running a 5857 at 14lbs making 450whp. I battled last year with overheating issues, and it seemed my overflow bottle was always full.

Tonight I did some tests on the cooling system.. Started the car up with no rad cap, and there were no bubbles coming up. But when I revved the motor up (2k-4k rpm) some bubbles would appear and a black oily residue would form.

I took the test one step further and did a (so-to-speak) leakdown test. I pressurized each cylinder when at TDC and looked in the cooling system for bubbles.

Cylinder 1 - 100psi - no bubbling.
Cylinder 2 - 100psi - a big bubble every 20 seconds or so.
Cylinder 3 - 60psi - lots of bubbling (consistent)
Cylinder 4 - 80psi - bubble every 5-10seconds.

Clearly my headgasket is letting Combustion gases into my coolant system. There have been no other symptons of bad gasket....ie no white smoke, no milky oil, etc. So the leak must not be that bad I guess?

I should note that when the engine was built, I compression tested it and the results were:

Cylinder 1 - 187
Cylinder 2 - 185
Cylinder 3 - 180
Cylinder 4 - 183

It seems this data perfectly correlates with my leak down test. Could it be that the head gasket was bad from the start??

It is a Cometic MLS 84.5mm, 0.031" thick. Using ARP head studs torqued to 81ft/lbs.

My question is, is it worth trying to re-torque? How would this be done?
Has anyone had luck with this?
Or should I just replace the headgasket (going to go with a GE 84.5mm one this time) and check my head/block for flatness again.
What is the max feeler gauge you guys allow for flatness?? I have read 0.002" is MAX.

Opinions/comments welcome! Thanks.

hondamark35

I had a head gasket leak after a rebuild recently. D-series with OE head bolts. even though oil was applied to the threads one bolt was a little noisy when torquing. proper procedure would be to loosen everything and start over if there is noise, but i was lazy and let it go the way it was. when i noticed it blowing coolant from the overflow bottle i loosened all of the head bolts, relubed the noisy one and retorqued them all. in this case it didn't eliminate it 100% (maybe 80% improvement) but i attribute the small leak remaining with a lack of copper gasket spray. i normally use it but had run out when installing this gasket.

so retorquing can improve the sealing of the gasket. it won't make it leak any worse.. i would give it a shot and see what your results are.

beenba

Yea I figure I can quickly try a re-torque while the engine is still in the car. A leakdown test would also be really easy after since the cams will not be in and all cylinders will be sealed.

FYI - When I built the engine, I drove it 200km and found out I has some bad valve seats. I had to pull the head and fix the seats, and then I re-used the gasket (with copper spray the second time)...

kyden

I've never retorqued head studs. I would replace headgasket and double check your tune.

beenba

The more I think about it, the more I want a new HG. Re-torquing just seems like a band-aid.

Some more info (about my tune). Tuned at a local reputable tuner. Running 14psi on 91 octane making 450. Total timing at WOT is 14-15deg. I'm also running an AFR of 10.5 at WOT. Very very conservative IMO.

Too be honest I doubt its the tune, however when the engine was being tuned the tuner did have to shut it down once to let it cool. The motor was running hot in the 190-200f range. Tuner had the heater core running inside the car. Maybe this is when it started leaking?

kanggoiseng

replace

Boosted_01 R

Get a Golden Eagle HG (Bored out OEM)....... cometic has lots of quality issues

beenba

Thanks for confirming guys, I ordered a golden eagle one. It was interesting to note my Cometic was also a 85mm and my bore is 84.5mm - although I was told this would work it may have played a small part.

What everyone's thoughts on copper spray? My head and deck are fairly flat (0.0015" in some spots), and they are not going to have a fresh re-decked or machined surface. Should I use some?

hondamark35

after experiencing the good results after using it i plan to use it from now on. it's cheap insurance and i'm unaware of any bad side effects.