Billet Injector Blocks

[hobieboy]

While rebuilding the top end, I noticed that a few of the factory plastic injector blocks were cracked.

Am thinking about going with aluminum billet ones instead. Other than Powerhaus, any idea who else might have them?

thanks...

[magic930]

I always thought it strange that these are plastic but then realized that it probably acts as an insulater keeping the intake manifold and the CIS head a bit cooler. Does that theory hold heat?

[hobieboy]

That's my understanding as well. The billet ones usually have an insulator in addition to gasket to serve the same purpose as well.

[350HP930]

+1 on their insulative abilities.

The engine also expands a bit more than the manifold so they also act as stress relievers. For that reason I will be sticking with the plastic injector blocks thanks to my one piece manifold.

[Wayne 962]

Hmm, the billet ones sound like a solution looking for a problem...

-Wayne

[hobieboy]

Well, the problem in my case is I'm considering porting the head - BA's book suggests 36mm but the factory ones only has 4mm wall thickness so can't be machined.

I'd be interested if anyone had good/bad experience with porting the 930 head?

[Steve@Rennsport]

FWIW,...We always use billet ones as the OEM phenolic injector blocks are very prone to crack.

When (not if) that happens, you get a big enough air leak that creates a severe lean condition and the consquences are very expensive.

[magic930]

Steve, Where do you get the injector blocks? Also noticed those billet cylinders on your site, who makes those?

[Steve@Rennsport]

We carry the billet injector blocks.

We designed those 102mm cylinders and they were made for us, right next door,... They were not cheap, but those were made at a time when Mahle could not deliver anything and "necessity was the Mother of Invention".