11 stud conversion - when to upgrade?

[timmy201]

I’ve noticed when I had my cylinder head off that there’s signs of exhaust blowing out the ends of the head gasket where the additional studs would be. Is this a sign that it’s in need of the extra studs?

My engine is an 1100, over bored to +080 and high compression. Is it possible to add the extra studs to small bore 998/1098 block/head?

[Workinprogress]

Can not honestly say if required or not, but Graham Russel in Australia on his web site has a how to.
Bruce

[winabbey]

Can not honestly say if required or not, but Graham Russel in Australia on his web site has a how to.
Bruce

Here - https://russellengineering.com.au/11-st ... bore-head/

[Spider]

They are nit necessary or desirable in my view. They take a less than great head stud arrangement and make it worse. The Metro Turbo Engines developed the most BEMP (Cylinder Pressure) of any factory engine, yet with all the R&D that went in to it, the factory didn't deem them necessary and they weren't an engine that was prone to blowing head gaskets. All I see them doing is 'bending' the cylinder head the wrong way, might help with sealing on the very ends, but makes it worse towards the centre of the head.

[timmy201]

Thanks guys. I’m not really keen on the modifications shown there, and now it makes sense why the 1275 heads are different at each end to make room for the extra studs

I know the optimal fix will be modifying the head to lower the compression ratio as now it’s above 11:1 . I’m hoping perhaps the new Victor Reinz head gasket will hold a bit better than the standard ones

I don’t suppose there are any little tricks with cam timing or valve clearances that can help tame a high comp engine?

[winabbey]

Timmy - have you spoken to GR about this? I was talking to him about something else a few minutes ago and mentioned your issue in passing. He thinks the Victor Reinz gaskets are good and certainly better than the copper ones generally available.

[Oneball]

I raced a 998 Cooper with 12.5:1cr for on 9 studs for years. Your compression ratio by itself isn’t the problem. Have you checked the basics; flatness, surface finish, studs pulling, etc? Is there enough clearance on a small bore gasket for +80 thou? Are you using a large bore gasket, if so the composite ones seem way better recently.

[timmy201]

Timmy - have you spoken to GR about this? I was talking to him about something else a few minutes ago and mentioned your issue in passing. He thinks the Victor Reinz gaskets are good and certainly better than the copper ones generally available.

I haven't called him yet, I was waiting to try and see if there were any other ideas

I raced a 998 Cooper with 12.5:1cr for on 9 studs for years. Your compression ratio by itself isn’t the problem. Have you checked the basics; flatness, surface finish, studs pulling, etc? Is there enough clearance on a small bore gasket for +80 thou? Are you using a large bore gasket, if so the composite ones seem way better recently.

The block & head were both decked when they were at the engine builder a few years back. I had used a GUG702506HG gasket as that's all I could buy previously and they did slightly overhang the bores between 1/2 and 3/4. The new Victor Reinz small bore gasket seems a better fit. I've been using the "road and lightly tuned" 9 stud kit from minispares as I was planning for it to be relatively mild..

[davidnutland]

We rana 1380 competition engine for many years on 9 studs never a problem.