Ok, here'e the situation. I have a 1904cc motor that I am building and I have a set of pistons and cylinders for 82mm crank. This leads me to having 5mm of deck height when I have everthing in place and the crank at TDC. Question, should I pay $130 to have the cylinders machined down? What are other options does anyone sell p/c sets for a 74mm crank? Is that even too much deck height for that engine? I am using info in a book on stock engine rebuilding and it suggests between 1mm and 2mm.
Thanks and merry winter to all!
Joshua
?deck height?
-
James2
- Posts: 3148
- Joined: Fri Mar 16, 2001 12:01 am
?deck height?
What year car? What CR do you want? what head CC? cam, heads, carbs????
The deck hieght depends on what CR you want. It's also better to run 1mm deck, but you can not run less! More may be ok, if you want a lower CR.
If it's a later model car, I would go with the "A" or stock stroke pistons. The engine should work out close. You may need a shim or two, but they are cheap. Engine maybe a little tight in a early car, but should still fit.
If you take 5mm (.196 of an inch) off the cylinder, doubt the shroud and sheet metal will fit with out some serious cuttting.
It all depends on what your trying to do.
But I still think using the stoke pistons is your best bet, unless you need to run a lower CR ratio.
[This message has been edited by James2 (edited 12-24-2002).]
The deck hieght depends on what CR you want. It's also better to run 1mm deck, but you can not run less! More may be ok, if you want a lower CR.
If it's a later model car, I would go with the "A" or stock stroke pistons. The engine should work out close. You may need a shim or two, but they are cheap. Engine maybe a little tight in a early car, but should still fit.
If you take 5mm (.196 of an inch) off the cylinder, doubt the shroud and sheet metal will fit with out some serious cuttting.
It all depends on what your trying to do.
But I still think using the stoke pistons is your best bet, unless you need to run a lower CR ratio.
[This message has been edited by James2 (edited 12-24-2002).]
-
Advokat
- Posts: 439
- Joined: Sun Jan 27, 2002 12:01 am
?deck height?
I'm building a 1904 right now too, used the "A" pistons/cylinders and still had to use .07 worth of shims to get the deck height right for my desired c/r.
Good luck
Good luck
-
nos14
- Posts: 136
- Joined: Sun Sep 08, 2002 12:01 am
?deck height?
Okay so here is more info on my engine and car,The car is a 74 Ghia and I have an Engle 110, the heads are 043 castings with 40x35mm valves with 55cc chamber and the carbs are 40mm dual dells. I think I am going to run about 7.5 CR, although, I am only doing that because it is near what stock runs. Any input here will be great.
Cheers
Joshua
Cheers
Joshua
-
James2
- Posts: 3148
- Joined: Fri Mar 16, 2001 12:01 am
?deck height?
Ok, to get that CR ratio, you need about 3mm of deck. I would bump it up a little to 7.7 CR and run 2.5mm deck hieght.
here's your choices-
A. have your cylinders cut and have a motor that is roughly 2.5mm shorter on each side.
B use the non stroker pistons and have a engine that is about 4mm wider on each side, you will also need a shim that is roughly 4mm thick for each cylinder.
if you can exchange your current pistons, the second method would be cheaper and easier.
here's your choices-
A. have your cylinders cut and have a motor that is roughly 2.5mm shorter on each side.
B use the non stroker pistons and have a engine that is about 4mm wider on each side, you will also need a shim that is roughly 4mm thick for each cylinder.
if you can exchange your current pistons, the second method would be cheaper and easier.