Jeep Strokers

yup do what dino said. i cut .018 off my block to get a 0 deck then after cleaning up the combustion chambers it added something like 6 cc's if i remember right

Whacking the block is a way of doing it but far from the idea way.

Frankly, I am disappointed that Scat didn't do a better job with piston selection. They sell a "kit" that most folks whom purchase it will think they are getting what they need for a good running stroker. If anything I am disappointed that a company of their reputation would sell such an incomplete, poorly engineered set up.

The Keith Black IC944/945 pistons have a compression height of just 1.353" which leaves them 0.027" down the hole at TDC. If you shave 0.027" from the block to zero deck clearance, you lose 5.3cc which you'd need to regain from the combustion chambers/piston dishes.
Couldn't Keith Black have produced pistons with a compression height of 1.380" and a 26cc dish (instead of 21cc) so you could build the engine with zero deck clearance and have the same CR without shaving the block?

Could the 4.2 rods with ARP bolts hold up to 8-10 lbs of boost? I am thinking I should probably go with you low compression crawler recipe with forged pistons? I already have those rods that came with the crank.

Cheromaniac wrote:The Keith Black IC944/945 pistons have a compression height of just 1.353" which leaves them 0.027" down the hole at TDC. If you shave 0.027" from the block to zero deck clearance, you lose 5.3cc which you'd need to regain from the combustion chambers/piston dishes.
Couldn't Keith Black have produced pistons with a compression height of 1.380" and a 26cc dish (instead of 21cc) so you could build the engine with zero deck clearance and have the same CR without shaving the block? :doh:

I am not at all comfortable milling the KB`s. Just the other day I was considering doing such a thing. Jeff Leigh warns against it on his web site.

Curious, I measured up a 944 that I had access to. The dome thickness was disappointingly thin compared to a Diamond. Granted, we are comparing a hyper to a forged but that doesn't make the engineering the KB did for the 944`s any better. From want I am seeing 944`s costing nowadays you can darn near buy custom Diamonds, Race Techs, JE`s etc. for just a few bucks more.

Wonder who made the Bulltears ?

rav wrote:Could the 4.2 rods with ARP bolts hold up to 8-10 lbs of boost? I am thinking I should probably go with you low compression crawler recipe with forged pistons? I already have those rods that came with the crank.

Depends on how good you are in rebuilding the rods. They are often oval, twisted and center to centers are off. Then so long as you have a piston to match it all up.

Your comments thus far yells to the fact that you are not ready for a FA engine or even a stroker at this point. Harsh but true. Spend some more time reading the fundamentals of engines and strokers in particular rather then how cheaply you can build it.

No offense to Dino but I would not build a low compression crawler under any circumstance. The parameters just don`t add up to my liking, sorry but that is just me.

jsawduste wrote:

rav wrote:Could the 4.2 rods with ARP bolts hold up to 8-10 lbs of boost? I am thinking I should probably go with you low compression crawler recipe with forged pistons? I already have those rods that came with the crank.

Depends on how good you are in rebuilding the rods. They are often oval, twisted and center to centers are off. Then so long as you have a piston to match it all up.

Your comments thus far yells to the fact that you are not ready for a FA engine or even a stroker at this point. Harsh but true. Spend some more time reading the fundamentals of engines and strokers in particular rather then how cheaply you can build it.

No offense to Dino but I would not build a low compression crawler under any circumstance. The parameters just don`t add up to my liking, sorry but that is just me.

You are right I am far away from actually doing this but money is not an option. I am not trying to be cheap but trying to make smart purchases. I am willing to spend what it takes to build a reliable stroker that can run 8-10 lbs of boost from a M90. The plan is to build the stroker on the side and run an M90 on the stock 4.0 that is quite healthy with 5-6 lbs of boost. I am just trying to do my research and have a plan in place and gather parts for the stroker.

rav wrote:

jsawduste wrote:

rav wrote:Could the 4.2 rods with ARP bolts hold up to 8-10 lbs of boost? I am thinking I should probably go with you low compression crawler recipe with forged pistons? I already have those rods that came with the crank.

Depends on how good you are in rebuilding the rods. They are often oval, twisted and center to centers are off. Then so long as you have a piston to match it all up.

Your comments thus far yells to the fact that you are not ready for a FA engine or even a stroker at this point. Harsh but true. Spend some more time reading the fundamentals of engines and strokers in particular rather then how cheaply you can build it.

No offense to Dino but I would not build a low compression crawler under any circumstance. The parameters just don`t add up to my liking, sorry but that is just me.

You are right I am far away from actually doing this but money is not an option. I am not trying to be cheap but trying to make smart purchases. I am willing to spend what it takes to build a reliable stroker that can run 8-10 lbs of boost from a M90. The plan is to build the stroker on the side and run an M90 on the stock 4.0 that is quite healthy with 5-6 lbs of boost. I am just trying to do my research and have a plan in place and gather parts for the stroker.

OK, then for your needs I would suggest reading up on the longs vs. short rod topic in the FAQ`s. Find out just what Scat is doing for the rod they are selling then compare that to what a competent performance machine shop will do in rod rebuilding.

Another thought is to look high and low to see if a set of Eagles could be had. Out of production for several (or more) years and are H beam design with an even longer center to enter then the 4.0`s. Someone somewhere has a set ferreted away.

For FI you will want a forged piston. That takes to straight to the custom market. Which is good because you can now spec your pistons to exactly what your needs are rather then trying to make do with an off the shelf part.

Talked with Mike Panetta of Diamond recently and their prices are very competitive on the basic design and go up slightly for each option requested.

jsawduste wrote:From want I am seeing 944`s costing nowadays you can darn near buy custom Diamonds, Race Techs, JE`s etc. for just a few bucks more.

Yeah you're not kidding, and with custom pistons you can get the exact spec that you need (provided you have the mathematical skills and engine knowledge to make the correct calculations).

jsawduste wrote:No offense to Dino but I would not build a low compression crawler under any circumstance. The parameters just don`t add up to my liking, sorry but that is just me.

No offence taken John.
A few guys have copied the rockcrawler recipe and have been very happy with the results 'cause it'll run on 87 octane and produce excellent low rpm torque, but it does have its limitations (not much power above 4500rpm) and it's not going to be everyone's cup of tea. That's why I also came up with other stroker recipes to suit different tastes and budgets. Different strokes for different folks you might say.

Cheromaniac wrote:

jsawduste wrote:From want I am seeing 944`s costing nowadays you can darn near buy custom Diamonds, Race Techs, JE`s etc. for just a few bucks more.

Yeah you're not kidding, and with custom pistons you can get the exact spec that you need (provided you have the mathematical skills and engine knowledge to make the correct calculations).

jsawduste wrote:No offense to Dino but I would not build a low compression crawler under any circumstance. The parameters just don`t add up to my liking, sorry but that is just me.

No offence taken John.
A few guys have copied the rockcrawler recipe and have been very happy with the results 'cause it'll run on 87 octane and produce excellent low rpm torque, but it does have its limitations (not much power above 4500rpm) and it's not going to be everyone's cup of tea. That's why I also came up with other stroker recipes to suit different tastes and budgets. Different strokes for different folks you might say.

Thanks Dino, you have done a lot of work in offering information to the stroker world. Something I simply would not have the patience for. I respect you for all your hard work and am glad to see that your passion is not blinded by a closed mindset.

Thanks for the kind words John.
There are others who have contributed even more than me (notably SilverXJ) and it's great that we can all share our experiences here and pool our knowledge.
I was just thinking that the Eagle forged rods (6.15") combined with the Keith Black IC944 pistons (1.353") would leave a near zero deck clearance. Just a shame that:

a) Those rods are no longer available and,
b) Those rods were designed for 0.912" diameter full-floating pins whereas the IC944 pistons use regular press-fit 0.930" pins so they're not compatible.

I called around every place and the eagle's are in fact extinct. I spoke to Bennie at Hesco and he was not aware of the SCAT rods or cranks. I sent him a link. He thinks his custom forged pistons with the 4.0 rods should be fine. He will get back to be after doing his dd about SCAT rods.

rav wrote:I called around every place and the eagle's are in fact extinct. I spoke to Bennie at Hesco and he was not aware of the SCAT rods or cranks. I sent him a link. He thinks his custom forged pistons with the 4.0 rods should be fine. He will get back to be after doing his dd about SCAT rods.

Bennies custom forged pistons are Diamonds. http://www.diamondracing.net/

Don`t think for a second that Hesco does not know about Scat. Not saying anything bad but Scat would be a direct competitor.