20 replies to this topic

[Dusky]

Try the calverst main bearing cap mod next time, cheaper and more effective than a main strap :)

[MRA]

How is it different ?

[Dusky]

http://www.calverst.... cap issues.htm

[MRA]

http://www.calverst.... cap issues.htm

 

Are you talking about the 4 bolt cap ?  in which case it would require line boring, but on the plus side it is the best there is, rigidity and strength are the ultimate in main caps.

[Dusky]

http://www.calverst.... cap issues.htm

 
Are you talking about the 4 bolt cap ?  in which case it would require line boring, but on the plus side it is the best there is, rigidity and strength are the ultimate in main caps.

read the article and what calver says about them.. the bit about the washers ;)

[MRA]

The washers spread the load from under the head of the bolt, it's better to make the caps out of Meehanite 250 cast and heat treated, it makes it a lot stronger and because it is better cast material than the block it does offer a lot of advantages.

 

The main issue with some 4 bolt caps is that for some reason people assume that the outer 2 bolts have to be the same size, they don't, in fact 5/16unjf (J is required) is the best size because it offers the results that having 4 fixings is all about, and that is stiffness, this stops the cap from deforming as much as a standard

 

My steel straps are hardened EN8 and this stops the heads from "working" in to the strap, also offers a lot more stiffness, but in all cases they need to be line bored. 

 

I find Keith's write up interesting, especially as my own 1380 turbo is running a standard cap.....