I am currently using a block guard in my LS/VTEC and I am having overheating/headgasket sealing problems.

I have noticed that the block guard doesn not fit very well into the open deck of the block. It fits snug most of the way around except for a couple of spots around where the cylinder sleeves meet each other. Very small gaps only at these points.(Pretty much where the block guard comes to a point between cylinders.) Example between cylinders #1, and #2 and so on.)

My question is... if there was a small gap like in my instance, would coolant being forced up through that small hole put enough pressure on the head gasket to blow it out and force coolant into the cylinders?

Or do you think that the pressure will be relieved enough by the coolant hole very close by, that flows to the cylinder head?

1 Stock gasket opened up to fit a 85mm bore... blown in 2k miles
2 Cometic gaskets LS/VTEC 85mm bore... blown in about 10 minutes.

Cylinder head pressure tested and check for cracks and warpage. None found. Everything good. Motor has the 2K miles that was on the stock headgasket listed above. This block has been resleeved and step decked at the time of rebuild.

Another question... why would it last 2K miles then just decide to blow?

Car was never driven hard....YET! which is why I'm getting upset!!

Any help would be appreciated.

Thanks

[Modified by Shft@9GSR, 6:26 PM 7/12/2002]


[Modified by Shft@9GSR, 6:27 PM 7/12/2002]

 

What kind of blockguard is it? Is it flush with the deck or recessed in a bit?

I researched this a lot when I was deciding whether or not to use a blockguard or post the block. Every one that I had talked to who had successfully used a block guard had machined it to fit PERFECTLY into their block, welded it in, and then bored/honed it to clean up everything.

Sonny

 

Thanks for the input. I know that the one I have is just a press in. No welding. If I have it welded, then have the deck shaved so it is flush, then it would eliminate the wondering. It would completely close it off so that the coolant holes are the only holes in the block guard. Maybe I will just do that. Thanks again.

 

If your engine is sleeved, you dont need a blockgaurd. How much power are you trying to make? Are you sure you need it?

 

QUOTE]My question is... if there was a small gap like in my instance, would coolant being forced up through that small hole put enough pressure on the head gasket to blow it out and force coolant into the cylinders?QUOTE]

are you saying if there was a small gap between the blockgaurd and the sleeve? think about what it looks like without the blockgaurd in there man..huge gap. the headgasket seals all the way around the top of the cylinder so no coolant can get in and no exhaust can get out. The blockgaurd won't cause any kind of headgasket leak at all.

 

I figured on that theory also, that if the guard is not there, then coolant flows in that whole area.

the thought I was having is that smaller the hole, the faster(more pressure) the coolant passes through the small hole. And with no passage past the gasket to flow into the head, the pressure would sit against the headgasket and maybe weaken it. the problem I am having is burning coolant. It never leaks externally out of the motor. Always into combusion chambers.

But after further looking at my block, the holes are actually very very small, and would not cause any problems.

I am currently getting the head looked at again from a different machinist. The first guy was a Acura Dealership's recommendation. This time it's going to my own machinist. I am starting to think that the head maybe warped slightly causing all my damn problems.

Thank you for all the responses.

 

you say the block has been resleeved...why do you want a blockguard in there? you do not need it.

 

20 lbs of coolant pressure doesn't blow head gaskets, compression from the combustion chamber blows them. Lots of things you post don't make sense to me. Why would you go to the trouble of sleeving the block and then ruin your cooling flow with a block guard? That's the beauty of the open deckGreat cooling around the cylinder. Why did you go to 85mm the first time? That's to large if you are boosted and very close to the end if you are n/a. I don't think the problem is with your head or the Cometic. Something changed on your block. Either a sleeve has dropped below the deck level or something shifted or warped. Run a straight edge across the sleeves to see if they are still above the deck. You may have to surface the deck and cut off the deck step. I hope your prob is with the head and not the block as the fix is much easier but why 2K easy miles? Maybe the sleave just decided it was time to settle in. Good luck.

 

out of curiosity, who did your sleeving?