Heating/ Compression issue????

[38flattie]

The engine performed well on the dyno, but we've had issues in the car

We went to El Mirage, and thought we blew a head gasket in the pits, so we changed it.

Took the car to the salt, and again thought we had a bad head gasket, and changed it again- all to no available

I brought the car home, and did a leakdown test- most cylinders Are 0-2%, with 2 cylinders at 4% at 90 PSI- so head gaskets look good, at least with no heat in the engine.

I put a diverter in the car, to first burp the problem side- drivers side , then the passenger side. The car runs great for 3-4 minutes, then the drivers side would spike. Now, I can move the issue to the passenger side, so I thought we had an air bubble issue.

I can now burp the engine before starting, and get what appears to be all the air out. After the engine runs 3-4 minutes, I get a steady stream of air out- see 1st video.

I tried putting the caps on the system, and the car got to 210+ degrees, and the system burped air even after I shut it off.

WTF? Any ideas?https://vimeo.com/103605463https://vimeo.com/103605487

[hotrod]

Some engines trap a lot of air, on my WRX it can take a week to get all the air out unless you take special care to burp it when filling it the first time by elevating the front of the car so the air trapped in the head can get out.

Have you had someone check the air that is coming out to see if it has combustion products in it (ie exhaust).

http://www.arrowheadradiator.com/head_gasket_or_combustion_leak_test.htm

An exhaust gas tail pipe sniffer can also detect carbon monoxide etc. In the air that is burped out as follows:

http://www.vehicleservicepros.com/article/10881931/diagnosing-engine-overheating-and-uncommon-cooling-system-problems-to-find-bad-water-pumps-had-gaskets-and-more

It might be coming from some place other than the head gasket, do you have coolant passages that are real close to pressurized intake passages (blower puffing air into the cooling system not the head gasket), or a tiny crack in an exhaust port that only passes exhaust gas under load and high temp?

Good luck on chasing this down.

[Milwaukee Midget]

ADDED AFTER HOTROD'S POST - I think we're on the same page . . .


Couple of thoughts.

As I recall, you have a really long run to the radiator in the water tank in the back.

First thing I'd check is to see if that's air, pressure from the intake side or exhaust getting into the cooling system.  The smell test would be sufficient.  I believe you are running more boost than water pressure in the system, so it could still be from the intake side.  

Something Mark stressed to me was that you want the highest point of the cooling system above the engine.

It's tough to get all of the air out, but if your radiator-tank sits lower than the engine, any air is going to head toward the highest point until it's forced through the system.

On a dyno, the water column is artificially made higher by the water being used in the dyno.  In the car, the dynamics are all self contained.

It's a thinker - I'm just thinking at the keyboard right now.

I hate plumbing . . .

[38flattie]

Thanks guys!

Chris, I'm going to try and jack up the car as you suggest, and see if I can 'burp' the engine better, and see what happens!

Larry, I never knew such an animal existed, but I just returned from NAPA with the kit! If the new 'burping' method does not clear up the problem, I'll test the water and see if that tells us anything!

[manta22]

Someone makes a kit to pull a vacuum on the cooling system and them it sucks coolant back into the system. You could probably fabricate one yourself that would do the same thing.

Regards, Neil  Tucson, AZ

[38flattie]

Thanks Neil! I may need to look into that!

[Richard 2]

Looks like to much air. And coming out to fast to be trapped air.
Richard 2

[38flattie]

Richard, that was my thought- what are you thinking it is?

Only thing I can think if, if it's not compression, is we either have a hotspot and are boiling the water, or somehow the intake air is getting in the water.

[Richard 2]

Do you have cylinder sleeves?

[38flattie]

No sir, we do not.

[Richard 2]

Well if there are no cracks or leaks in the Heads, Head Gaskets, Top of the Block, and no place for the boost to cross over to the coolant via a hose or super charger (and if it is getting hot quickly, I wouldn't think it would be boost pressure by its self). I guess I would be looking at the Cylinder walls. Could be a every small pin hole.
My best guess not knowing the Engine. Richard 2

[38flattie]

Thanks Richard! I'm going to keep looking!

[hotrod]

What kind of water pump are you running?

I have seen heating problems due to a water pump which had a loose impeller on the shaft, it would spin when hot and under load not pumping much water.
At low load it appeared to work just fine.


Do you have a way of monitoring your cooling system pressure?
If so does the cooling system pressure increase uniformly as it heats up or does it suddenly spike at a certain boost pressure or engine rpm/load?

Water pumps can also suck long hose sections flat under high flow, if there is a restriction (like trash caught in the line) and possibly pull air into the system on the suction side of the pump (or past its seals).

Did this start just after you had those freeze plug leaks at Speed week 2013 or one of your other events?
(just trying to maybe get a hint based on how/when it started)

[38flattie]

Larry, this problem started after we installed the engine I'm the car this year, after the dyno.

We blew the head gasket on the dyno, when we added 10% nitro. We took the engine home, changed the head gasket, and to the car to El Mirage. We've had issues since. At first we thought it was just a head gasket, but have replaced it 3 tomes, with no evidence of an issue there

I do not have a wY to monitor my coolant psi. This is the same setup we ran the previous year with no issue

It is a mezeire pump, and the suction side hose is only about 12" long

[Freud]

Why don't you switch to an air cooled Caddy block?

You have made everything else. Make one of those !!

That makes me feel better already.

FREUD