Head Gaskets

[robbo]

Hi all
I want to start getting the bits I need to replace my head gaskets. The BGA head gaskets which are available all seem to be the thick ones. Question is if my heads come off ok and don't need a skim will these be ok to use or do I need thinner ones ? I have been scouring all the old posts on the subject but any more help and advise will be much appreciated.
Cheers Rob.

[milothedog]

Hi all
I want to start getting the bits I need to replace my head gaskets. The BGA head gaskets which are available all seem to be the thick ones. Question is if my heads come off ok and don't need a skim will these be ok to use or do I need thinner ones ? I have been scouring all the old posts on the subject but any more help and advise will be much appreciated.
Cheers Rob.

Rob, can I suggest you hold off on the gaskets until you get the heads off, you will then be in a position to know exactly what you need. Re using the think gaskets. It wouldn't be a problem but you may not need them, and hopefully not, but if your heads are bad more drastic action may be needed.

Ian.

[Mark Shutt]

when you get the heads off and they appear nice and clean with no corrosion and the valves are still below the mounting surface then standard gaskets will be fine. usual scenario is they've been skimmed a lot before and on the limit of how much material can be taken off so will need extra thick gaskets. like said above you won't know until everything is apart and inspected

[Staggard]

I used BGA gaskets for me it was the quality not the size, I could not see that 20thou would make much difference one way or another. What I would say that is very important is to re touque after first running the engine and at least another couple of times at regular intervals. I have retightened my heads three times in 1000mls and they have gone down each time. Graham

[Arbman Al]

I used BGA gaskets for me it was the quality not the size, IGraham

I keep telling my wife that as well...

[Goldstar]

Robbo (and anyone else who might need standard head gaskets) SOCTFL has funded a project with Abinger Hammer to produce standard gaskets. The gaskets will be produced by BGA - one of the biggest automotive gasket maker in the sector. We saw the first batch last week and they look good. Not sure when they will be available but it shouldn't be too long

[DJT]

Robbo (and anyone else who might need standard head gaskets) SOCTFL has funded a project with Abinger Hammer to produce standard gaskets. The gaskets will be produced by BGA - one of the biggest automotive gasket maker in the sector. We saw the first batch last week and they look good. Not sure when they will be available but it shouldn't be too long

Nice to see SOCTFL getting involved even if it is 12 months too late for me. I could have used std gaskets, but chose to use BGA XT ones as they were the only decent gaskets available............

[flying farmer]

Robbo (and anyone else who might need standard head gaskets) SOCTFL has funded a project with Abinger Hammer to produce standard gaskets. The gaskets will be produced by BGA - one of the biggest automotive gasket maker in the sector. We saw the first batch last week and they look good. Not sure when they will be available but it shouldn't be too long

Oh Good News!

When I am building my high performance engines and trying to get the compression ratio up, I am fighting a losing battle with thicker gaskets.

The engine that currently resides in the Estate has good heads and County pistons that only gave a measured 8.5:1 compression with standard thickness gaskets.

I grabbed a couple of sets of Payen standard thickness gaskets while they were still available, but have only one set left now after building the project Stag, and I have 4 cars with Stag engines!

Having once used a cheap standard thickness gasket that wouldn't keep the water in, I wouldn't like to go down that route again!

Glad to hear that SOCTFL have got involved with this!

Neil

[robbo]

Thanks for all the advise guys. I have re torqued the heads down to 55ftlb on Saturday been out for a drive this morning around 30miles and no coolant lost. Still getting a very slight weep into the v but no puddle just a dampness so much better than it was before. I will monitor how things go. I know I will have to do them at some point hope they last until the winter. But in the mean time I am going to see if I can free the studs one at a time remove them grease them up put them back then re torque until I am ready to do the gaskets. The bolts are no worry as they are all free.
Cheers Rob.

[Paul Roberts]

Rob,

What follows is absolutely sound engineering advice; but it must be doused with a healthy dollop of practicality and common sense.

When torquing down the head/heads - on our V engines - the inlet manifold (a single casting sitting between two independent heads) should be slackened off to allow for necessary movement between head and manifold.

For every dimensional unit (of movement) the head moves down the bolts/studs it moves equally inwards (towards the opposite head.)

If the inlet manifold is attached tightly to both heads; something has to distort in order for the head movement to take place.

Many joint faces/gaskets will tolerate a small degree of movement but, eventually, something will have to give.

My advice? Don't be alarmed but do be aware.

[Goldstar]

Nice to see SOCTFL getting involved even if it is 12 months too late for me. I could have used std gaskets, but chose to use BGA XT ones as they were the only decent gaskets available............

Sorry Dave, be ready for you next time though

[DJT]

Rob,

What follows is absolutely sound engineering advice; but it must be doused with a healthy dollop of practicality and common sense.

When torquing down the head/heads - on our V engines - the inlet manifold (a single casting sitting between two independent heads) should be slackened off to allow for necessary movement between head and manifold.

For every dimensional unit (of movement) the head moves down the bolts/studs it moves equally inwards (towards the opposite head.)

If the inlet manifold is attached tightly to both heads; something has to distort in order for the head movement to take place.

Many joint faces/gaskets will tolerate a small degree of movement but, eventually, something will have to give.

My advice? Don't be alarmed but do be aware.

Paul,

I can understand where you are coming from with this, but if just re-torquing head studs the movement of each head will be only a few thou. This will have no noticeable effect on the inlet manifold. Slackening the inlet manifold will certainly result in those gaskets failing and require total removal of the manifold. If re-torquing the heads required this to be done, it would be mentioned in the ROM, and would certainly have been raised before. Yet this is the first time I have ever heard it suggested for our engine.

The ROM suggests slackening one head if replacing manifold gaskets, a practice which has been discredited many times. If the manifold were to be slackened in order to tighten a head, then a head would need to be slackened to replace the manifold gaskets, and round in circles we go.........

[DJT]

Sorry Dave, be ready for you next time though

Hopefully there won't be a next time......

[Paul Roberts]

Paul,

I can understand where you are coming from with this, but if just re-torquing head studs the movement of each head will be only a few thou. This will have no noticeable effect on the inlet manifold. Slackening the inlet manifold will certainly result in those gaskets failing and require total removal of the manifold. If re-torquing the heads required this to be done, it would be mentioned in the ROM, and would certainly have been raised before. Yet this is the first time I have ever heard it suggested for our engine.

The ROM suggests slackening one head if replacing manifold gaskets, a practice which has been discredited many times. If the manifold were to be slackened in order to tighten a head, then a head would need to be slackened to replace the manifold gaskets, and round in circles we go.........

I totally agree with you, Dave - especially regarding your "circular" argument - hence my comment relating to ".... practicality...." etc,.

However, if - for whatever reason - e.g. new engine, replacement thicker head gaskets, etc., there was significant movement; there is a very limited amount of movement the inlet gaskets/manifold will tolerate.

Imagine if each head tightened down by just 0.5mm (not an unheard of amount) that's 1mm overall inward movement too. That is going to cause a lot of stress somewhere in the construct. The inlet manifold casting is either having to distort or fracture to permit this head movement or the heads can't go down flat against the block.

To be honest; it's not one of the finest ever bits of engineering to leave the drawing board... . but we still luv em..... .

All of that said; if it ain't broke, .... , etc.

[Motorsport Micky]

"To be honest; it's not one of the finest ever bits of engineering to leave the drawing board... ."

you are in imminent danger of being cast from the Stag Owners club, don't you know you aren't allowed to make critical (yet absolutely correct) comments about the Stag and it's engineering.

Micky