Beater 2316, CR versus deck height

[grootspeed]

Also posted on 914world, but, I think there are more type 4 engine builders here.....

So, finally getting around to building a "beater" engine to develop my race car project (been idle too long). The idea is to build a reliable, decent engine that's not crazy expensive to sort out my car, then put in the expensive engine when the chassis is ready. I will only use race fuel with this engine.

Basic specs are:
96mm JE pistons
AA Biral cylinders
80mm crank, chevy journals
5.4" Chevy rods
2.0L heads (Hoffman prepped) 51.3 cc
168/86B cam

So, to get ~0.040" deck height, I'll need 0.210" barrels shims (checked this today), but that puts me at a calculated CR of 10.7:1

Now, the question... should I source 0.220" or larger shims to drop the CR at the expense of deck height? A shim of 0.220" will drop the CR to ~10.4:1, but raises the deck height to 0.050"

Thoughts?

[Clatter]

If race gas only, why not 10.7?

That's a typo on your cam, right? 163/86B..

[grootspeed]

Yeah, typo.. thanks.

[bj]

I had my 2316cc built almost the same:

80mm crank
96mm KB pistons "C" pin height
3.525" rods (chevy journals)
163/86b cam (108 LC)
~9.5:1 compressions though...we'll see.

my builder wanted a .060"deck, so we went with, if i remember right, .090" shims/spacers.

he felt that that .040" was a bit too close for comfort.

the stock push rod tubes all worked fine with this arrangement.

CAVEAT: this was built a while ago and I had kids...car is still sitting. hasn't started in a LONG time . getting there...though...

not sure if this helps or not.

Good luck.

BJ

[grootspeed]

Cool.

What cylinders? With my AA birals, pistons (30.08mm Compression Height with a 22mm Pin) and that rod, I would have needed a lot larger spacer to get the DH correct.

I ordered the 0.210" spacers... going with 0.040" DH.

I clearanced the rod caps yesterday, plenty of clearance now.

['77 Westy]

For my 2316 I used:

96mm AA Biral cylinders
KB Hypereutectic pistons – 22mm pin, 28.21mm compression height
5.325 H-beam rods, VW journals.
Scat C25 cam

9.0:1 CR, 0.060" deck and I used 0.090" spacers.

[bj]

i'm using bored out stock 94 jugs done by Rimco...back in like 2004-ish...

if you use more than .120" spacers...you'll have to get creative with your push rod tubes...if memory serves me...better check though.

my compression is kinda high for the crappy gas we have here...but i'm going to run it and see what happens...i may have to adjust my head CC's to lower my compression a little.

Forgot to mention that with the chevy/buick journals and the reduced base circle cam, there were no clearance issues either.

BJ