13 replies to this topic

[WiredbyWilson]

This isn't the composite Vs copper question.

 

I have recently seriously blown through a fire ring using a composite gasket so am now considering a cometic all metal gasket to stop this happening again.

 

They come in various sizes and the US company have asked for the bore size. Now as i didn't build the engine, rather had a machine shop do it i will give what i know and let the boffins feed back.

 

The engine is a 1330 with 21513 pistons running a Morspeed Ph3 Can, fully lightened bottom end and a BMC Works head.

 

The standard composite HG I removed measured 0.91mm which is around 0.36 thou?

 

From memory the machinist said he machined the block 0.15 thou and the pistons to match.

 

So would i be right in thinking i need a 0.51 thou Cometic gasket - or could I get away with a 0.40?

 

The reason I ask is Burton Motorsport have a 0.40 gasket in stock, 0.45 is 4-5 weeks and 0.51 is 8-14 days.

 

I want my mini back but don't want to kill it!

Edited by Wilson1330, 23 September 2013 - 07:43 PM.

[seancv1]

I'd err on the side of bigger if no one in the know gets back to you silly high compression kills engines ! Slightly lower compression will only have a slight loss in performance ! I thought composite gaskets were quite good have you checked both block and head for cracks / deformations ?

[WiredbyWilson]

everything has been checked, the fire ring broke up and the 2 parts were on top of the piston!

 

Both the block and head cleaned up and has been checked for straight-ness.

 

think being stood up then driven hard goosed the gasket.

[The Principal]

BK450 has never failed on me - http://www.minispare...|Back to search

[KernowCooper]

Not normally a issue on a 1330 on the bigger blocks the engine builder would bore the block to the centre of the gasket bore to give the max amount between cylinders, I have a 1330 and running a BK450 gasket without issues, are you sure it was not torqued down with oiled studs and the firing ring over compressed?

[WiredbyWilson]

I fitted the HG myself and have been working on cars for 15 years alongside my uncle. It was torqued down as per Haynes, and then again about 50 miles later.

 

My major concern is the compression ratio due to the deck and pistons being machined........... Can a BK450 cope with that along with being stood up over the winter?

[WiredbyWilson]

I have one of these in the shed - what are the thoughts? I was impressed by the final comment re Bill Richard Racing used one for 500 miles and that it was perfect when removed?

 

http://www.minispare...px|Back to shop

[The Principal]

your not running anything extreme, if it was me i'll go for the BK450. I run that gasket on far hotter engines no problem

[KernowCooper]

They are really good gaskets, I assume it blew between cylinders if you get a gasket and lay it on the block is the boring central to the gasket and what is the remaining thickness looking like on the block, some of the OE bore centres went that great on tolerance from the factory. I cant see a winter layup making the firing ring on the gasket fail. I'd be measuring up with a new gasket on to see if the firing ring is in relation to the bore

 

I'd not put anything other than a Payen made gasket, lots of engines on here with failures of non Payen Gaskets

Edited by KernowCooper, 23 September 2013 - 08:15 PM.

[WiredbyWilson]

I will need to lay the copper one over the bores and go from there. But I will get hold of a Payen gasket based on those giving advice.

 

Is it best to torque the bolts dry or wet?

 

AND - is it worth getting competition head studs - as i don't know the history of the studs i'm currently using.

http://www.minispare...|Back to search

[seancv1]

Don't arp recommend torquing down wet albeit with there own special engine building lube

[KernowCooper]

Never had issues with standard studs/nuts torqued correctly dry myself

[MIGLIACARS]

I used a kinetic gasket on my race supercharged engine. as advised by my engine builder.

the engine lasted no more than 2 hours before catastrophic failure due to a poorly designed gearbox.

when stripped down i found that between 2-3 the gasket had failure on the 3 lower layers,these are very expensive gaskets at around £80,

since then ive rebuild the engine myself, to reduce costs i used a bk450, its now done about 6 hours of use and touch wood its been up to the job.

 

when fitting the head make sure everything is spotlessly clean.

[Cooperman]

I always use the BK450 and my 'S' is running at 11.1:1 CR. Never have any problems with that gasket.