Problem with Head Gasket blowing more than once

[Jerry]

I had just replaced the head gasket on my TR3A and it blew again this weekend. I though the issue was a dip in the head between #2 and #3 cylinders. I had the head checked and decked. That made it measure flat with my staight edge. Do any of you know of other areas that are sensitive on these cars? I know I will have to look for cracks now also. I think the sleves don't give much space in the block for the gasket to stay connectd. When I put the last gasket on, I checked the compression and it was 175 in each cylinder.

Jerry

 

[kindofblue]

Did you follow the proper torqueing sequence? Did you tighten all the cylinder head bolts to specification? Did you make sure that all of the grit and debirs was clear of the block and head before installation?

I know its elementary, but one miss here could be causal.

 

[Jerry]

Yes to the torque, yes to the sequence, no grit was there but something caused it again. I guess I will know more when I pull it off.

 

[Banjo]

2 things.
It's critical to re-torque the head after getting it up to temprature once and letting it cool off again. Not doing this almost ensures a failure.
If that has been done then a second possibility is flattened out "figure 8" gaskets on the bottoms of the cylinder sleeves. If these get crushed, the gead gasket won't properly seal. The tops of the cylinder sleeves should protrude from the block just a little. If they're flush, then you need new "figure 8" gaskets.

 

[sp53]

If this is a recurring problem are you sure that it is a head gasket? Could it be a crack in one of the sleeves? If the sleeves stick up above the block and you have had the head redone and check out and you are using a good quality gasket, it might not be the head. Does the gasket show a clear blow out between the cylinders?

George

 

[Geo Hahn]

Re: Problem with Head Gasket blowing more than onc

Since you seem to have eliminated several common causes, my guess (as noted above) would be that the liners are not standing proud of the block. They need that little bit to really clamp down the edge of the cylinder hole.

Be sure to check them all around their circumference as I've heard of cases where they are correct on one side and low on the other.

An important clue that might help... where on the gasket did the failure occur?

 

[Jerry]

Re: Problem with Head Gasket blowing more than onc

I have not taken it apart yet this time but the last removal showed the gasket blown towards the water hole between number 2 and 3 cylinder. The number three bent the gasket toward the water hole. My assumption with a straight edge was that the head in that part had about a 2 thousands dip. So I had the head machined. I did not check the liners sticking above the block because I assumed I had found the problem. I think I will pull the engine and check everything this time. I have never pulled the liners before, do I need any special tools?

Jerry

 

[Geo Hahn]

Re: Problem with Head Gasket blowing more than onc

[ QUOTE ]
...I think I will pull the engine and check everything this time. I have never pulled the liners before, do I need any special tools?

[/ QUOTE ]

No need to pull the engine to check this. The liner should protrude above the deck by .003 to .005". You can check this with feeler gauges and a straight edge though you can easily tell if they stick up by just using your fingernail.

 

[Banjo]

Re: Problem with Head Gasket blowing more than onc

Geos' right about checking them. but if they need replaced you can still do it in car. You have to remove the pistons and then you can knock them out from below . I use a wood block or an old hammer handle as a drift. Sometimes you have to use a good bit of force to get them started. Be careful to keep them straight. if they cock off to one side they stick tight.
Follow the shop manual closely for install.
Also mark each cylinder for position and orientation (i.e. #1 front) so they go back in exactly as they came out.
Its also a good oppertunity to clean any scale off the outside of the sleeves. this will make your cooling system more efficent.

 

[TR3driver]

Re: Problem with Head Gasket blowing more than onc

[ QUOTE ]
but if they need replaced you can still do it in car.

[/ QUOTE ]

That's true, but it's not an operation for the faint of heart. When you knock the liner out, all the accumulated crud in the water jacket will fall out right onto your nice clean crankshaft journals.

I've had lots of liners that wouldn't come out beating with a block of wood, so I made up a "brass drift" out of a length of 1" water pipe, plus one brass pipe cap and one iron. For $8 at Home Despot on a Sunday night, it works slick.

In addition to cleaning the outside of the liner, you should clean the inside of the block as well. Finish by cleaning the liner seats, of course.

On my last TR3A, it appeared that the TR3 block was machined wrong by the factory. The result was that the liner protrusion was correct when measured on one side, but non-existant on the other ! Rather than having the block re-machined or replaced, I soldered a ring of copper wire to the head gasket around each cylinder. Worked fine for many years and still doesn't leak, even after changing the head and reusing the same gasket /ubbthreads/images/graemlins/eek.gif

 

[stob62]

Re: Problem with Head Gasket blowing more than onc

Stupid question, but how did you know you blew it--oil, check compression, what?