Jeep Strokers

This is my recipe it works great with no pinging on 93 octane gas, but I think i'm missing on some power benefits from a high performance cam, I feel the engine is stronger, plenty stronger than stock, but I'd like your experience on cams, I've been running my stroker for about 8 months and like it, but if i could have more power....

What cam would you recommend:

4.5 stroker
1993 4.0 block/ obd1
Stock pistons dished to 23 cc
no overbore
no block shaving
4.2 crankshaft and rods
Hi volume oil pump
Stock camshaft
victor reinz head gasket
Ford 24lb injectors

daccarettfletez wrote:This is my recipe it works great with no pinging on 93 octane gas, but I think i'm missing on some power benefits from a high performance cam, I feel the engine is stronger, plenty stronger than stock, but I'd like your experience on cams, I've been running my stroker for about 8 months and like it, but if i could have more power....

What cam would you recommend:

4.5 stroker
1993 4.0 block/ obd1
Stock pistons dished to 23 cc
no overbore
no block shaving
4.2 crankshaft and rods
Hi volume oil pump
Stock camshaft
victor reinz head gasket
Ford 24lb injectors

With the pistons dished 23cc, and no block decking(high quench), I would think your compression ratio is pretty low. This could be causing a lack of power also. Running a bigger aftermarket cam might lower your compression ratio even lower because of a longer valve overlap and later intake valve closing. Have you ran your numbers on a compession ratio calculator?

Yes my dcr is almost identical to the stock 4.0

What if shave the cylinder head would that get my compression up?

Well if your compression ratio is very close to stock why not add a supercharger...? If you did it eat V8's for breakfast

As much as I'd love to...too much $$$$$$. The cam I can afford

daccarettfletez wrote:What if shave the cylinder head would that get my compression up?

Yes it would, but a lower quench will help with a higher compression ratio and still be able to run a lower octane gas. My stock 4.0 would ping on 87 octane. My stroker runs on 87 octane with .043 quench, zero deck(9.25:1 scr, 7.75:1 dcr).

If being cheap is what your after,ie: a cam, shaving you r head to raise comp. isnt a horrid idea, but it doesnt do anything beneficial for your quench numbers unless you install a thin(er) HG, like .043". If you shave your head w/o addressing some of your quench, you may open a can of worms(read: your knock could get very bad).
-Will

Most cams will increase you DCR. New cam, valve springs would help...

Roller cam , Pick your poison:

http://shop.505performance.com/category ... egoryId=31

daccarettfletez wrote:This is my recipe it works great with no pinging on 93 octane gas, but I think i'm missing on some power benefits from a high performance cam, I feel the engine is stronger, plenty stronger than stock, but I'd like your experience on cams, I've been running my stroker for about 8 months and like it, but if i could have more power....
What cam would you recommend?

According to my calculations, the SCR of your engine is only 8.9:1 so that's going to blunt performance a bit but you should be able to run 87 octane fuel.
I suggest you go for a Compcams 68-231-4 cam, upgrade to Mopar Performance 5249464 valve springs with matching retainers/locks, shave 0.030" from the block deck to increase the SCR to 9.5:1 (you'll end up with roughly zero deck clearance and a 0.043" quench), and add 0.030" thick shims under the rocker arm bridges to compensate for the increased lifter preload from the block shave.
While you're there, it wouldn't be a bad idea to replace the pushrods with Crower chromemoly hardened units and swap in a set of Yella Terra YT6627 shaft-mounted roller rockers to add stability to the valvetrain.

Cheromaniac wrote:

daccarettfletez wrote:This is my recipe it works great with no pinging on 93 octane gas, but I think i'm missing on some power benefits from a high performance cam, I feel the engine is stronger, plenty stronger than stock, but I'd like your experience on cams, I've been running my stroker for about 8 months and like it, but if i could have more power....
What cam would you recommend?

According to my calculations, the SCR of your engine is only 8.9:1 so that's going to blunt performance a bit but you should be able to run 87 octane fuel.
I suggest you go for a Compcams 68-231-4 cam, upgrade to Mopar Performance 5249464 valve springs with matching retainers/locks, shave 0.030" from the block deck to increase the SCR to 9.5:1 (you'll end up with roughly zero deck clearance and a 0.043" quench), and add 0.030" thick shims under the rocker arm bridges to compensate for the increased lifter preload from the block shave.
While you're there, it wouldn't be a bad idea to replace the pushrods with Crower chromemoly hardened units and swap in a set of Yella Terra YT6627 shaft-mounted roller rockers to add stability to the valvetrain.

Don't forget to add the double roller timing chain to that equation. I found out the hard way

Biggrnjeep97 wrote:read: your knock could get very bad
-Will

where is this thread? I would like to read it.

Jak Flash wrote:

Biggrnjeep97 wrote:read: your knock could get very bad
-Will

where is this thread? I would like to read it.

What he meant is that the can of worms he was referring to could be bad knock.

I'm going to go a completely different direction than anyone else...

What power do you want?

Do you want to leave riced up hondas 4 car lengths back at stop lights and chirp big off-road tires on dry pavement?

Do you want big peak HP numbers on a dyno sheet, Or want to pull on turbo'ed hondas doing 80mph on a lonely freeway, or zip around an off road dirt course at 4000-5000 RPM's for hours on end?

Do you want to "mile an hour" at the drag strip or "60 foot"?

You can't really do both under a small budget. If you can afford a cam, then you can improve power up high or down low (depending on what you already have), they both have there own set of unique design choices. Without making the engine larger or fundamentally more efficient (lower internal friction and higher breathing efficiency) you have to tune for one or the other. You can emphasize torque later in the RPM's or earlier in the RPM's (or somewhere in the middle where most mild cams will fall).

Horse power (AKA higher RPM torque)
bigger ports (larger cross sectional area), shorter intake runners, bigger throttle body, long tube headers with larger primaries, 2.25" or bigger exhaust, more cam "valve overlap" and duration and lift (less trapping efficiency to gain more CFM air flow at higher RPM's) low dynamic compression

Low/mid Torque
smaller ports, longer intake runners, bigger throttle body, long tube headers with smaller primaries, 2" or smaller exhaust, tight cam with little to no "overlap" period and moderate duration (air velocity and trapping efficiency more important than large CFM flow) high dynamic compression

Higher compression will benefit both, but you need to tear down, machine and re-gasket for that, same with better quench (allowing more timing advance and more compression before ping creeps in on the same fuel). Aftermarket fuel and spark control tuned on a dyno will probably improve both simply because the factory stuff has lots of built in "safety margin"and emissions oriented tuning choices, which a performance oriented tune will improve on. But that's expensive.

I would say you're not getting the most out of your combo, if you truly have near factory static compression somehow (as Cheromaniac figures) while having such bad quench, from the stock deck with 4.2 rods and 4.0 pistons. I'm terrible with numbers, but the last time I looked at that combo I seem to recall a 4.0 piston on a 4.2 rod and crank leaving the piston ENTIRELY too deep in the hole for effective quench... something like .090 or .100 quench distance... I'm not sure where that puts your static compression ratio but just off the top of my head I think it would have to be pretty bad... maybe I'm mis remembering. Dino did you take into account the pin hieght of his stock 4.0 pistons on 4.2 rods? I seem to recall this combo being an OKAY low budget choice with a block decking to get near factory quench, but without decking I recall it being pretty much unusable... I'm probably not remembering correctly.