I removed the ported 243s from my combo and went with TFS 220s. I was pushing some water with my 243s, so I figured I would upgrade. I have had the TFS heads on for a week. They started pushing water on about the 5th or 6th street pull. I made 4 pulls on Sunday, 2 on 8 psi and 2 on 14 psi. Came home and the overflow was full. Drained the overflow, added some more coolant and went out and made some 8 psi hits and filled it again.

Setup has brand new LS9 gaskets, brand new TFS 220 heads with 70cc chambers, reduced compression from the previous combo, brand new ARP2000 studs torqued to 80 ft. lbs with ARP moly. We did everything right. Tune was very safe, low 11's AFR on the 14.5 psi pulls and no more than 13 degrees of timing and mid 11's with 14.5 degrees of timing on 8 psi. Great IATs, plenty of fuel from brand new ID1000 injectors.

The only thing that has not changed at all is the cooling system. The car runs nice and cool, never overheats. I have a truck water pump, custom crossflow radiator, electric fan and a Kurt Urban steam vent kit. I am going to replace the thermostat, relocate the fifth line on the Kurt Urban from the water pump to the upper rad hose and get a higher pressure cap (mine is a 14 pound). However, I really do think that is pie in the sky. I think I am pushing water due to combustion pressure.

The whole reason for these heads was the increased deck thickness and the resistance to lifting and pushing water.

So, I am curious to see if anyone else has pushed with these.

 

Drained the overflow? As in radiator overflow? Or the breather catch can? In my experience, pushing water from Cyl pressure usually shows up in the breather catch can(s). Pushing into your rad. overflow is usually cap pressure. A small amount of this is ok if you have an overflow capable of recovery as well. (like the OEM overflow tank)

I've pushed 25+lbs on 317's with LS9 gaskets and arp studs. Seen 23lbs this year on 243's with china studs. Never seen a drop of water on either engine. So I don't think head clamping force/surface area is the issue.

I believe the LS1 OEM cap spec is 18psi. I've got a 22psi cap on my C5 vette? Was on there when I purchased it, not sure if thats standard or not.

 

I drained the radiator overflow. I then added some more water to the radiator, I left about a 3 inch gap at the top as these LS motors tend to like some room for expansion. I am talking about pushing water, not blowby. I have a catch can, it has not filled up in a year of use.

I ordered a Stant "racing" cap that should hold 22-23 psi. We will see if that helps. It took me a year to push with 243s, LS9's and standard ARPs (that had been torqued 10 times) with around 10.3 compression, running as much as 20 psi of boost.

This has me really mystified.

 

You could pressure test the radiator and make sure you don't have some sort of tiny crack in the block. But in general I wouldnt' sweat fluid in the rad over flow. You can also put a gauge on your coolant system and monitor it during a pass. I believe skinnies logs this info and his rad pressures were surprisingly high.

I have a 1 gallon funnel I use to burp the coolant system. Initially topped off with my engine hot the funnel was probably close to 3/4 of the way full. As the motor cools it will suck it all back in if I let it. I'd get a big funnel with a plug and burp the system. While the motor is hot and the level is highest, I pop the plug in and pop on the cap. That should get you about perfect.

 

I am not pushing out an ounce or two. It is filling the overflow with brown, shitty, foamy coolant with enough force to blow the cap off of it (it is a cheap plastic job from Autozone) after 4 low boost pulls. I could live with a little overflow. This is different.

I have a transducer that I am going to install into a heater hose line so I can monitor the pressure. However, I need to get this squared away first.

 

put a rad pressure tester on it and pump it up to about 10# and then break torque it up against the convertor if it heads for 30# within a few seconds you need to take it back appart.

 

Are you sure the deck surface of the block and heads was correct? Who did the machine work?

Are the heads new?

 

Heads are brand new. Deck had not been an issue before. I pressurized the radiator today. It held pressure well, but coolant was clearly dripping out of the passenger side gasket. So, it must have lifted and smoked the gasket.

 

OP, we need to talk. I have been encountering the exact thing that you are. Although I'm at 20+psi.

This is a vid from about a month ago. The overflow system I had could not handle the pressure/volume so it actually lifted the cap up.

 

What kind of heads are you running? For me, the entire point of the TFS heads was to prevent this kind of thing. This setup has half a point less compression and was on a very safe tune with superior head studs to the last setup. I really don't know what went wrong here. I will swap the gasket this weekend and get my transducer installed into the cooling system.

 

I wouldn’t just toss another HG In. If you don’t feel your tune was off I’d mark the injector of the failed cylinder and have them all flowed/cleaned. Flowed the injectors on my last motor that let go and one of them was total junk. My want to check the deck with a quality machinist straight edge tool as well. (jegs/summit sells them cheap)

Normal cyl pressure at those levels shouldn’t push a gasket, even on an OEM head. Something is warped or there was a cyl pressure spike. Whats the plug look like?

 

Interesting that you mention that. The first batch of injectors had a dead injector, so I had a cold hole. I think the uneven cylinder pressures could have contributed to the issue. I ordered a brand new set of ID1000's and they are in there now. I also tossed my belt, twice, although I noticed that immediately and pulled over and fixed it. Manual tensioner ended that issue forever. Plugs all look very good.

 

Not what you want to hear but...If the plugs look great on the cyl thats leaking, sounds like a warped deck surface to me. If the inj. went lean I think you'd see it on the plug. Ever had a bad HG blow out on that block?

 

The injector was dead from the get go, as in it never worked. The cylinder only leaks under boost. You could drive the car to California and it would run cool and never push if you stayed out of boost. So, it is not going to show much as there are miles of just driving and idling on the plugs as well. This block has a good surface as far as I know. Something happened along the way. I ran the car on wastegate for 3-4 pulls and never pushed. I was chucking the belt, so I ordered a manual tensioner. The next time I took it out I made 4 hits, 2 on gate and 2 on about 14-14.5. When I got home, I had a full reservoir.

 

Try a new radiator cap before you pull the heads.

 

Time to get the hands dirty and why I'm going n/a all the way.

 

I had the same issue a few months ago at 28psi. Then it did it at 25psi then again at 20psi. Thought I had lifted a head getting aggressive with it. It wasn't pushing that much water but it was enough to get everything wet. Turned out to be my radiator cap went bad, replaced it with a new one and all good to 30psi.

 

If it is leaking that badly, then something is very badly wrong and it needs to come apart.

Typically lifting heads will be a short duration blast of pressure into the system, but with MLS gaskets normally they seal very well again after this.

If you're leaking water the way you say, it needs to come apart and a thorough inspection needs done.

Ensure studs are correct length and nuts not bottomed out, ensure torque wrench is reliable, all gasket surfaces smooth and flat etc etc

Logging via a transducer is probably best, but you can just as easily stick a simple mechanical pressure gauge onto it as long as you can view it safely.

 

I have a new cap as well. Has anyone run a cap with high pressure? I was running a 14 psi cap. this one is now a 20-25. Is that going to be too much? I did test the 14 psi cap and it was working fine.

Also, it has never been my experience that MLS gaskets "reseal" after they lift. Every time I have had a leaker, and I have had a few, the head(s) needed to come off. Even if you don't see damage to the gasket, they are damaged once the seal is broken.

Mike

 

Integrity will not be as new, but they wont be pissing water out the side like yours is. IMO that isnt a head lifting problem, that's a serious problem with the gasket.