CR
Turbo Mini Forums

hello all only my second time of measuring the CR in my engine.... just wanted to see if this sounded about normal.

I have got my hands on a 1275 an old 1300 Austin engine, with a remote box. I cant find much on the engine number.

Anyhooo I and used the CD cover with a hole in but i could only get my hands on a small syringe 2.5mm so its not ideal....

The pistons in the block at TDC measured 18cc

I have been given a 126904 from a mate as the one on the engine was knackered and this measured 25c but this seems a lot??? looking at them they seem like a standard size, but I'm used to small bore stuff..

looking at the calculator this would give me about 8.0:1

thanks for an help

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

they look like they have been opened out abit to me. although my experience is limited.

what is your engine specs?

bore strok etc.

EDIT: just looked at you post! what an idiot!

using http://www.csgnetwork.com/compcalc.html it says 7.7:1

uhmm either im doing something wrong or that is very low.

is that supposed to be a standard block?

if it is i would say somethings a-miss with the measurements.

Edited by James_H on 18th Nov, 2008.

I used 2.7 for the gasket 18cc for the bores, and 25 cc for the head on a 1275cc engine and got 7.98:1???

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

what boost are you runnine?

was the block standard when you measured it?

Edited by Rod S on 19th Nov, 2008.

Schrödinger's cat - so which one am I ???

seems about right to me calculation wise

http://www.afracing.com/CR.xls

AlexF

Sounds about right to me aswell, just a tad on the low side really unless you're going for silly boost?

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

I'm with Rod on this some of the fluid has probably got past the rings,

what i wold sugest is trim down a cd so it will drop into the bore and sit on the piston, then you can measure the actual dish, then with the pistons at tdc measure the deck height and work that out.

also as Rod says get a bigger syringe, there will be errors due to refilling it.

thanks guys boots didn't have any.. whats the standard dish on the 1275?? am I close? I measured a 1.1mm from the bore to the top of the piston at tdc

remeasured the head but at the head at 24cc t

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

ok,

1.1mmto the top of the block will give 4.3cc.