77 scorp restore

[JeffAW]

I am redoing my 77 scorp could some help me with the following ques.

1. what might the C/R be with a new 124 Fiat 2L short block stock pistons and 1.8L head with oversized valves
2. where would I get the cyl head gage "Lancia-SAT-88015038" ref in Scorpion & Monte carlo Technical Data book pg DT-MC-01/0455
3. what is the formula for C/R
4. what is the bore and stroke of a 2L


Thanks Jeff off list add all41res@yahoo.com

[DJ]

I am redoing my 77 scorp could some help me with the following ques.

1. what might the C/R be with a new 124 Fiat 2L short block stock pistons and 1.8L head with oversized valves
2. where would I get the cyl head gage "Lancia-SAT-88015038" ref in Scorpion & Monte carlo Technical Data book pg DT-MC-01/0455
3. what is the formula for C/R
4. what is the bore and stroke of a 2L


Thanks Jeff off list add all41res@yahoo.com


1. Consensus seems to be that it would be ROUGHLY about half a point higher than stock. Somewhere around 8.5:1. Best to cc the chambers with the head in place if you need a more precise value.

2. The folks at mirafiori.com have run a tool crib for such things for a long time. Suggest you go over there, join the Fiat Page Interactive Forum and post a query. Ask for Pete Angel in the subject line and you should get a prompt response. He may be able to help you find one. If you PM or email me directly I'll give you his email addy.

3. I'm certainly not the best person to answer this but someone else here surely can. It's one of those things I never remember and have to look up whenever I need it.

4. Bore 84.0mm Stroke 90.0mm per manufacturers specs.

[Will]

1) It depends on the flycuts you will make for the new valves- bigger valves may require bigger cuts, increasing TDC volume that you reduced with the 1.8 head. It also depends on how much the new valves occlude the chamber from the seat line, which depends on the valve itself and the seat- the only sure way is to measure, and knowing the exact static CR is overrated IMHO, it's the dynamic CR that counts and you can get that with a tester easier than measuring things out, and what difference does it make if you are going with stock pistons? For that matter, why are you increasing the valve size, wouldn't a nice set of HC pistons be eminently more worthwhile?

2) I don't know where you can get the tool, but you can check the proximity of the valve seats to head gasket surface to tell if a stock head's been cut down. You could also CC the head and tell that way.

3) It's the ratio of the total volume at BDC to total volume at TDC. Don't forget the volumes of valve cutouts, head gasket, and CC the head with the spark pliugs you'll use. Bear in mind that knowing this exactly is practically worthless for all practical purposes- especially at near-stock compressions, unless you just like to be able to say "Hey, I have an 8.2:1 CR motor"

4) 84x90 as DJ said, another quick way to find swept volume is to divide displacement by the number of cylinders- in this case 1995/4=499cc. Dividing displacement by half the number of cylinders gives you Volumetric Efficiency=1 (998cc per rev)