Head gaskets third time in two months torque settings

[sandyt]

Afternoon all I am doing the Head gaskets on my 4.6 p38 for the third time in two months some of it my fault some not but interestingly the torque is 15lbft plus 90 plus 90 anyway today I thought I would see what I ended up with and was amazed that the values went from 85 to 100 lbft. My assumption was that they would be about the same as the bolts should be manufactured to a good tolerance anyway would welcome any comments

 

[wammers]

The 15lb ft has to be done several times before you start the angle tighten. Going over the head once at 15 lb ft is not good enough. Go over it let it rest for a while then go over again. I like to do three passes each with a wait for the gasket to settle. Before starting angle tightening. You must also make sure the bolts screw in freely lightly lubricated or the initial 15lb ft will vary.

 

[StuckAgainSteve]

The 15lb ft has to be done several times before you start the angle tighten. Going over the head once at 15 lb ft is not good enough. Go over it let it rest for a while then go over again. I like to do three passes each with a wait for the gasket to settle. Before starting angle tightening. You must also make sure the bolts screw in freely lightly lubricated or the initial 15lb ft will vary.

That's pretty much the method I use, I also screw the bolts into the threads as far as they'll go before the heads go on to make sure they are clean, you'll be surprised how often you get a bolt that feels sticky - which would have probably resulted in an incorrectly torqued bolt.

I've never (knowingly) had a head gasket go on an engine I've replaced one on. Above tips plus scrupulously clean mating surfaces. I close my eyes and feel the surface - you pick up bits you can't actually see. If something looks clean, the brain tricks you into thinking it's flat when you feel it with open eyes!

 

[The Mad Hat Man]

That's pretty much the method I use, I also screw the bolts into the threads as far as they'll go before the heads go on to make sure they are clean, you'll be surprised how often you get a bolt that feels sticky - which would have probably resulted in an incorrectly torqued bolt.
!

got an old bolt and put a couple of cutting disc slots through the threads lengthwise and use as a thread chaser.

 

[sandyt]

Well they are on and I ran the bolts in before putting the heads on went over the surfaces three times to make sure that they were clean and when torquing down went to 15 left for a cuppa did them again and the bolt between 6 and 8 needed a tad more then 90 wait whilst replaced orings (20 mins ) then 90.
She is running sweet again so we shall see.
Now the gearbox has a bit of a thump when changing down in each gear - did notice when heads off that two breather pipes had melted thing they may be from gearbox will have a good look with some light. The biggest challenge is light as I leave for work at 5 30 and get home at 7 anyway thank you once again gents for your help will keep you informed as to how she runs

 

[wammers]

Well they are on and I ran the bolts in before putting the heads on went over the surfaces three times to make sure that they were clean and when torquing down went to 15 left for a cuppa did them again and the bolt between 6 and 8 needed a tad more then 90 wait whilst replaced orings (20 mins ) then 90.
She is running sweet again so we shall see.
Now the gearbox has a bit of a thump when changing down in each gear - did notice when heads off that two breather pipes had melted thing they may be from gearbox will have a good look with some light. The biggest challenge is light as I leave for work at 5 30 and get home at 7 anyway thank you once again gents for your help will keep you informed as to how she runs

Think the problem these days with composite head gaskets of sometimes unknown vintage is getting them to settle. Maybe taking them to 30lbft letting them settle then backing off and then doing the 15lbft maybe a better option.

PS. Where are you getting your gaskets? If they don't have PAYEN on them they are not worth fitting.

 

[sandyt]

The gaskets are Elring struggled to find Payne
The problems I have had are more to do with my bad decisions should have replaced rad and when I put helicoil in used 1d instead of min 2.5 d still a learning curve

 

[wammers]

The gaskets are Elring struggled to find Payne
The problems I have had are more to do with my bad decisions should have replaced rad and when I put helicoil in used 1d instead of min 2.5 d still a learning curve

Think Payne used to make fireworks if you want gaskets it's Payen. Believe they have stopped making head gaskets but there should still be plenty of old stock about. One thing you don't want is Chinky or Indian gaskets. They are absolute crap. Gaskets made from compressed cow **** are not a good idea.

 

[sandyt]

Sorry about that predictive text and gaskets not made out of chocolate the ones I used are Elring from Germany anyway so far so good so lets see
But yes dont use ****e