lil-bump

iTrader: (89)

Can I use a .21 rear engine gasket for a gasket between the pipe header on a .12 engine?

Derby Bros Racing

iTrader: (7)

Yes. Newer pipes use .21 size (big bore) gasket. Some old school one-piece pipes use .12 size .

Nexus Racing

I've found that sometimes when you're using a gasket from a different mfg than the pipe, you'll need to trim the "lip" inside the .21 gasket with an x-acto to make the pipe and header still able to slide together.

Team Kamikaze

iTrader: (3)

You can also do this: Instead of trimming the inside lip of the seal/gasket, just use the PICCO .21 exhaust seal/gasket, the Picco seal/gasket does not have a lip on the inner side.

Garaski

totally different topic but an engine question(s)..... when do you add head shims ? how many do you add ? what do you guys look for ?

Team Kamikaze

iTrader: (3)

It depends on what engine you are running the nitro percentage you use and the altitude.

lil-bump

iTrader: (89)

I can comment on only .12 size engines. You want to check the top of the piston and burn room for detenation. It will look like the top of your piston has been sandblasted. This is bad you need to add shims. do a search in the nitro engine forum there is a ton of information on this subject.

Garaski

nova engine..... 25% nitro ...... #6 - #7 plug ..... what should I look for inside the engine to make me want to add headshims and how many should I use ? thanks.

lil-bump

iTrader: (89)

For 20% I shim around .45mm, 25% around .55mm 30% around .65mm. Like Team K said It depends on what % nitro you use

lil-bump

iTrader: (89)

Thanks for the replies