Low compression and blowing out antifreeze

[DooAssassin]

My Apex is blowing all its antifreeze into the overflow bottle. So I did a compression test and noticed the one cylinder was low. 123 100 123 123.

Pulled the head tonight but noticed no damage. Where do I go from here?

JE pistons
ARP studs
Carilio rods
MCX 260 kit

 

[greenthumb]

I would think the head gasket would have failed. Sometimes the damage can be pretty difficult to see. I would have a good look at the gasket and be happy if that's all it was.

 

[RED]

I would checked the cylinder head & block for being straight. If that checks out fine, send the head out for pressure testing.

 

[DooAssassin]

I should mention that it had a accidental over boost. A boost hose popped off and was giving me a incorrect reading but I didn't know at the time. I turned up the manual boost to see if it would increase the boost, but didn't show on the gauge. I estimate I was boosting around 20 psi on pump, the gauge was showing 10psi. It was not that long till I realized what was going on. 2 pulls up to 120mph. I turned around and brought it back to my garage, the overheat light came on when it was in front of the garage. I brought it in and changed the oil and filled the coolant (which was in the overflow can. ) Went for a 5 min ride brought it back in again and the overflow can was full again. So I knew there was a problem...

 

[DooAssassin]

#2 from the clutch had 100 psi

 

[DooAssassin]

#2 piston

 

[DooAssassin]

#1 (good)

 

[DooAssassin]

#2 piston

 

[DooAssassin]

#2 cylinder

 

[mbarryracing]

You can see the carbon tracking past the #2 fire ring on the head gasket, you definitely rattled it on those pulls.

 

[kinger]

mbarryracing - Still looks good though dont you think? Replace the head gasket and go?

Good pictures DooAssassin

Man these motors are tough.

 

[mbarryracing]

yeah, looks like just the gasket got woofed (weakest link, like a relief valve...). If you didn't over heat anything then the block and head decks are fine. I agree with ya kinger, I'd just replace the gasket and go.
Make sure the surfaces are cleaned up good with acetone...

 

[yooper1]

Since it is apart check the head that it is true and flat. Cheap insurance and maybe install new head bolts or studs.

 

[greenthumb]

Since it is apart check the head that it is true and flat. Cheap insurance and maybe install new head bolts or studs.

X2

Was going to say the same thing but then I noticed that you already had aftermarket studs. Poor head to block connection in often the cause of head gasket failure, especially on modded engines.

 

[Wildman]

If you rattled it I would check the cylinder bore for roundness and taper (as much as you can with the pistons in). .400 to .800 down from the top of the deck is most crucial. I am willing to bet they are egg shaped (maybe you got lucky though). Also check the head as during an overheat you can warp it.