Jeep Strokers

Cheromaniac wrote:Make the chamber volume 57cc and the altitude 0 feet.

OK got it.. is there an advantage or disadvantage going over .020 vs .030?

Slight increase in displacement for .030" over. It won't be noticeable as far as power wise. .020" allows you extra room to bore later if needed.

I've sonic tested a bunch of 4.0 blocks. Both early and late.
Wouldn't hesitate to go 3.935 (.060). Plenty of cylinder wall to maintain a round cylinder wall
with no concerns of overheating.

It's just my opinion, but we're not talkin about Lamborghini cylinder blocks here.
Considering a Jeep 4.0 engine is pretty plentiful and probably has a value of less than
$200.00, I wouldn't compromise the the project worrying if you have to rebuild it again.

In a rare chance you hurt your block, you could always machine another block and throw your
rotating assembly and head back in it.

To give you some perspective. I'd say 80% of the strokers I build start with a .060 overbore.

Russ

I think Russ has a great point. These blocks are not hard to find and are really cheap. If I were to do it again I would go .060 over with little regard for my original block. The 4.0 block is a dime a dozen.

Question: is the 9.25:1 CR going to run in 87 octane..

bellator50 wrote:Question: is the 9.25:1 CR going to run in 87 octane..

It depends on a number of factors but if you use Bulltear pistons and go for zero deck clearance with a 0.043" quench height, there's a good chance the engine will run on 87 octane without issue.
Just make sure you take care of other small details (feathered-edged and smoothened combustion chambers, cooling system, fuelling).

Cheromaniac wrote:

bellator50 wrote:Question: is the 9.25:1 CR going to run in 87 octane..

It depends on a number of factors but if you use Bulltear pistons and go for zero deck clearance with a 0.043" quench height, there's a good chance the engine will run on 87 octane without issue.
Just make sure you take care of other small details (feathered-edged and smoothened combustion chambers, cooling system, fuelling).

What do you mean of "feathered-edge" and of what. Also if I raise up the cc's in the head to lower compression , will that have a negative effect on engine.

bellator50 wrote:What do you mean of "feathered-edge" and of what. Also if I raise up the cc's in the head to lower compression , will that have a negative effect on engine.

Any sharp edges in the combustion chambers and piston dishes could cause preignition, so "feathering" those edges will prevent that. Smoothening and polishing the combustion chambers and piston dishes also helps to prevent detonation, and the slight reduction in SCR will also allow you to run a lower grade of fuel.

So another question. I plan on using Bulltear pistons. My concern is if compression height 1.380 is used and I deck block to 0.00 will this combination still work or do I need to change something __ again

You will give your mech shop all of your parts and they will mock it together, measure, then mill your block for a 0 deck height... if that is what you tell them that you want. At this point the compression height of your pistons is practically irrelevant. If you have a 0 deck height that means that they come all the way to the top no matter what their compression height was when the block was std. Also, if you want a lower compression ration and you need to add volume to the Combustion chamber then the head is a great place to get it. Although it may be easier/less technical to dish your pistons. If you decide to CC the head then you will likely add a little volume along the way.

Hope someone can answer this for me. Here is where I am at I have a 258 crank and OE 4.0 rods. I intend to go with Bulltear pistons with 26 or 27.5 cc dish. The question is what needs done to the rods far as machine work.

If my crank is no good, anyone have thoughts on this kit.
http://www.cleggengine.com/stage-ii-4-6 ... -1c-r.html

In that Cleggengine link, I checked out what they offered and found that their Stage II kit comes with:

Icon 4032 Forged Dish Pistons -27.5cc #IC668
Cast Piston Rings #E667 Scat Enterprises 9000 Series Performance Cast Steel Crankshaft 3.895” Stroke #9-4.2L-3895
Connecting Rods 4.0L 242ci 6.125” Reconditioned
King Connecting Rod & Main Bearing

Has anyone heard of the IC668s? I didn't find them anywhere else online. I did find an IC968 for a Chevy. .
You'd want to click all the options(even the rods) if you went the kit route.

I caled Clegg and was told the pistons were new and made for them as customers wanted a lower compression.

bellator50 wrote:Hope someone can answer this for me. Here is where I am at I have a 258 crank and OE 4.0 rods. I intend to go with Bulltear pistons with 26 or 27.5 cc dish. The question is what needs done to the rods far as machine work.

If my crank is no good, anyone have thoughts on this kit.
http://www.cleggengine.com/stage-ii-4-6 ... -1c-r.html

This is when you do a mock up of the engine and see what you have.

Well got tired of the looking around and bought the Clegg kit as mentioned in prior post with the forged rods and Moly rings. .I'm sure could have gone cheaper, looking around but what a pain.