Decking, quench, and compression ratio help for 4.1?

[Nick Micale]

Trying to figure some stuff out and need some help. I'm building a 4.1 stroker...........Thanks

I do not know any competent engine builder that would just measure and calculate, and would NOT do a assembly mock up on a stroker V-6 engine?

You have the block and rotating assembly, and there WILL be some mods for clearance even with the proper parts. So your questions will be answered, and you can determine what to do from there.

So the smart and easy thing to do is swing the crank and rods to see where you ACTUALLY are dimensionally.

To do this job right, the cam and timing chain need to be installed also to check rod/cam clearance.

You may find you have more, or fewer, issues, but at least you will know exactally what needs to be done.

 

[Sleeper]

I'm not sure what calculator you're using but I see what there doing. In stead of asking for rod length they're asking for the distance between the top of the piston and the deck. The only way to do this is to buy parts and install them into the motor and then measure. This doesn't help you pick out a rod and piston combo. What do you do if it's wrong? This calculator is for determining what the compression ratio of an assembled motor is. If you want to use a compression ratio calculator to help you choose a piston and rod combo,use the link I provided.

Sorry, i was using the calculator that was given to me in post #4

Nick,
This isn't the machinist's fault. When I bought the parts, the seller posted that they would work in any stock or stage I block. Thinking this was the case, I proceeded to get the block cleaned up and machined for the 4" slugs, not realizing I would have a deck height issue. He was just going on setup and parts I provided him with. I ASSumed it came from a 4.1 and would work in another 4.1 Never even considered the DH would be a problem, and didn't ask him to measure it for me. After I got the short block home all assembled, I had a closer look and saw that the pistons looked a little far down in the bore, and here we are....

 

[ek02]

A suggestion for the CR issue if you have a dished piston. CC the block with the piston at TDC (rings installed and some grease around them). Get the piston dish volume by subtracting the volume of the cylinder at TDC if the pistons were flat. CC the heads. Get the volume for the head gasket. Add the TDC cylinder volume, head volume, and gasket volume. Then figure the total volume of the cylinder at BDC and add the volume of the dish. Do the math and you will know the actual compression ratio. Yea, it's confusing and a lot of work, but it will give you the exact ratio.