my early plans on a 4.6l stroker........any advice?

[NorCalChris]

Basically a 4.6 low buck stroker option 1


96+ 4.0 block (casting # 53020569)
91-95 4.0 ported head (casting # 7120)
72-80 4.2l Crankshaft (casting #3214723) machining 1cm off the nose
4.2l rods shot peened and balanced (707 casting?)
mopar performance head gasket (0.043)
Clevite bearings (cam, main, rod)
balanced Speed Pro h825cp pistons + 0.030"
Hastings piston rings
camshaft has yet to be determined. I still need to plug the numbers in on the computer (what are you running?)
valve springs TBD after cam
Yella Terra 1.6 roller rockers
any pushrod recommendations?
Mopar Performance High volume oil pump #P4529241
Pioneer freeze plugs
I haven't decided on hi flow water pump or not.
99+ intake ill grind some of the casting marks away.
bored throttle body (any comments on Leigh Performance Machine? recently Ive heard good things about them.)
cold air intake (thinking about moving filter into the cowl) and keeping the stock set up for smog, unless I can find a CARB legal intake of my liking)
Ford injectors with a hesco regulator (anyone ever use Leighs machine's FPR?)
Cloyes dual roller timing set
Borla header? ( i prefer an equal length design. any recommendations on headers? keep in mind CARB legal)
2.25 in down tube w/ 2.5 cat and spin tech muffler.
MSD 6AL ignition box w/ rev limiter, blaster coil, wires.

This is my early plans on a stroker engine. Probably going in a yj :laugh3:. Im not building this anytime soon seeming how i just graduated from college. Im still broke. But nothing wrong with planning ahead lol. Other then that I'd like some advice. If the parts are good, bad, or ok. Thanks guys

[Dr. Dyno]

Sounds like you've got your combo well sussed but I'll suggest the following:

1. Standard volume oil pump. A HV pump is overkill and you may need to use a low viscosity oil to keep the cold start oil pressure below 60psi.
2. Make the exhaust downpipe 2.5".
3. Leigh Performance Machine do good stuff so you can get your 62mm TB from them as well as the FPR.
4. A high-flow water pump will keep the engine cooler when you run it under high load e.g. scaling long inclines so it's a good idea. Flowkooler or Hesco; take your pick.
5. CompCams 68-231-4 cam gives a nice balance in the torque curve over the 750-5250rpm operating range. Use Mopar Performance valve springs #5249464, retainers #4452032, & locks #4529218.

[old_man]

Personally I like the H802CP pistons. Roller rockers are great for high RPMs, but strokers aren't normally run at high RPMs. Roller Lifters on the otherhand would be a nice upgrade but a bit spendy.

[NorCalChris]

Sounds like you've got your combo well sussed but I'll suggest the following:

1. Standard volume oil pump. A HV pump is overkill and you may need to use a low viscosity oil to keep the cold start oil pressure below 60psi.
2. Make the exhaust downpipe 2.5".
3. Leigh Performance Machine do good stuff so you can get your 62mm TB from them as well as the FPR.
4. A high-flow water pump will keep the engine cooler when you run it under high load e.g. scaling long inclines so it's a good idea. Flowkooler or Hesco; take your pick.
5. CompCams 68-231-4 cam gives a nice balance in the torque curve over the 750-5250rpm operating range. Use Mopar Performance valve springs #5249464, retainers #4452032, & locks #4529218.
Ok, no on the HV oil pump and yes to a hi flow water pump. works for me.
why do you suggest a 2.5in down pipe?

[NorCalChris]

Personally I like the H802CP pistons. Roller rockers are great for high RPMs, but strokers aren't normally run at high RPMs. Roller Lifters on the otherhand would be a nice upgrade but a bit spendy.
what do you like about those pistons the most?

[yossarian19]

The factory down pipe is the most restrictive part of the exhaust. It is crimped to clear the front drive shaft during suspension flex. This also means it flows less.
As the most restrictive part of the exhaust, it gives the best bang for the buck when you upgrade it.
2.5" from the manifold back is your best bet. If you weren't going to do that, you could get most of the benefits from a 2.5" downpipe and a high flowing cat.

[NorCalChris]

Is the stock down tube 2.25?

[Dr. Dyno]

Is the stock down tube 2.25?

Yes but at the bends it's crimped down to as little as 1.75". It's very restrictive even on a stock 4.0, never mind a 4.6 stroker.

[old_man]

what do you like about those pistons the most?
Price is good, the combustion volume is what I wanted. I decked the block .025 IIRC and it yielded a 10.4:1 compression ratio with the .043 MOPAR gasket and a quench height of .058 IIRC. Even with the high CR, I can run regular gas with no ping.

I have over 100k on my stroker.

[NorCalChris]

Yes but at the bends it's crimped down to as little as 1.75". It's very restrictive even on a stock 4.0, never mind a 4.6 stroker.

I know about the crimp, it pretty hard to miss haha, but I didn't know the stock tube is 2.25. I will definitely be going to a 2.5in down tube.

[NorCalChris]

Price is good, the combustion volume is what I wanted. I decked the block .025 IIRC and it yielded a 10.4:1 compression ratio with the .043 MOPAR gasket and a quench height of .058 IIRC. Even with the high CR, I can run regular gas with no ping.

I have over 100k on my stroker.
With a 10.4:1 CR are you running 91 octane fuel? Also, what is an ideal quench height? .040-.060? have you ever dynoed your jeep to see what kind of power you built?

[yossarian19]

With a 10.4:1 CR are you running 91 octane fuel? Also, what is an ideal quench height? .040-.060? have you ever dynoed your jeep to see what kind of power you built?

He said he can run regular, which I take to mean 87-89. Ideal is considered 040 to 060, IIRC. I suspect he has not dynod it but I'm open to correction on all counts.

[old_man]

With a 10.4:1 CR are you running 91 octane fuel? Also, what is an ideal quench height? .040-.060? have you ever dynoed your jeep to see what kind of power you built?

I run the cheapest lowest octane on the pump with no ping.

[cracker]

I run the cheapest lowest octane on the pump with no ping.

renix or HO?

If it is Renix, is it possible the knock sensor is holding it back?

[old_man]

Renix, and I don't think the timing is being retarded by the ping sensor. I am running the high altitude CPS so the timing starts off advanced about 6 degrees anyway IIRC.

[Dr. Dyno]

renix or HO?

If it is Renix, is it possible the knock sensor is holding it back?

Tom lives ~5000ft above sea level where the air's ~17% thinner so his 10.4:1 compression engine behaves, in effect, like an 8.6:1 compression engine and that's why he can run low octane gas without pinging. If he came down to sea level he'd need 93 octane.

[cracker]

Tom lives ~5000ft above sea level where the air's ~17% thinner so his 10.4:1 compression engine behaves, in effect, like an 8.6:1 compression engine and that's why he can run low octane gas without pinging. If he came down to sea level he'd need 93 octane.

Interesting.....

What do you recommend for an ideal CR? (I live at sea level).

[NorCalChris]

Tom lives ~5000ft above sea level where the air's ~17% thinner so his 10.4:1 compression engine behaves, in effect, like an 8.6:1 compression engine and that's why he can run low octane gas without pinging. If he came down to sea level he'd need 93 octane.

i didn't realize he is so high in alt. I see how its possible. I am basically at sea level. Im planning on mid 9's for CR.

[old_man]

Ran just fine for me at sea level.

[NorCalChris]

So I'm still looking for advice on push rods(chromoly or not), headers, and cams that others are using. Also does anyone run a 5w oil in their stroker?
One more thing, what is an advantage to running say a .040 quench then .060? Is it the increase in cylinder pressure?

[kf_chris]

I have a HV oil pump and I have no cold start issues...and didn't in the cold winter weather.
Running KB944 pistons and I think the the CR is somewhere around 8.7? I'd have to ask the builder.
For a cam I'm pretty sure (working from memory) that I have the -231 comp cams extreme 4x4
Tons of low end and it falls on it's face around 4500, but I have only had it up that high maybe 4 or 5 times since it's been built (10K miles)
I went with the high dollar Banks Torque tube header
For Oil I use 30w Brad Penn oil, for the camshaft
Went with camsaver lifters

edit
also a 62mm TB, and it's super snappy with this build. lots of fun to drive

[NorCalChris]

So after doing some research, the only difference in the 802cp30 and the 825cp30 is the ring size. The 825 uses slighlty...and I mean slightly larger rings.
Another thing, after realizing my quench would be around .082, i have decided to mill the block. attempting to bring my quench near .045, and allowing my quench to be .050 max. I will be between 10.24 CR (with .050 quench) to 10.34 CR (with .045 quench). I will have to cc my head to see what my volume is so i can open it up a little hopefully bringing my CR down to 9.5:1-10.0:1.