4.5 stroker questions

[mikey_d_13]

hey, i decided stroke my jeep to a 4.5..i bought a 4.2 motor from a 84 cj
the parts are ready to be picked up from the machine shop..i had the crank ground, pistons pressed on the rods, cam bearings pressed.
i will be picking up tomarrow and starting the assembly so i wanted to clear a few things up.


this is the recipe i used..
4.5L Low-buck simple stroker

~ Jeep 4.2L 3.895" stroke crank
~ Jeep 4.2L 5.875" rods
~ Jeep 4.0L 3.875" standard bore pistons
9.7:1 CR
~ CompCams #68-231-4 206/214 degree camshaft
~ Ported HO 1.91"/1.50" cylinder head
~ Stock 0.051" head gasket
~ 0.081" quench height
~ Ford 24lb/hr injectors

my questions are..
i know theres a few different cranks..will the 84 fit right in without spacers or anything?
will i be able to run 87 octane?
if not should i have the pistons dished? if so how much?
with the cam, no other machine work will need done?

[4.whoa]

You didn't mention valvesprings. Stock springs won't work. The seat will almost certainly need to be cut for proper install height as well. I think that '84 is a long crank and would need a spacer or to be cut down.

[mikey_d_13]

I ordered the kit from summit that comes with the springs and evrything.do you kno what kind of spacer or how much to h ave cut?

[4.whoa]

IIRC its 1cm. You can get a spacer from hesco or make one from an old balancer.

So..... you bought a cam/ spring kit? AFAIK they don't yet make one with springs for the 4.0 head. They have 4.2 springs - and they DO NOT fit.

[gradon]

You won't have to cut the seats if you use the mopar P5249464 springs. I had my machinist cut a spacer out of an old 258 HB, but by the time I paid to have the $10 HB shipped and paid the machinist, I could've spent an extra $5 an gotten the Hesco one.

[Cheromaniac]

my questions are..
i know theres a few different cranks..will the 84 fit right in without spacers or anything?
will i be able to run 87 octane?
if not should i have the pistons dished? if so how much?
with the cam, no other machine work will need done?

1. You'll either need a 1cm spacer in front of the harmonic balancer or you'll need to cut 1cm off the crank snout.
2. You'll need 91 octane or higher with that combo.
3. The OEM pistons aren't thick enough to allow much dishing but by all means polish them smooth. You can also reduce the CR by unshrouding the exhaust valves and polishing the combustion chambers.
4. You can use the Mopar 5249464 valve springs without machining the spring seats, and their installed height is the same as the stock springs.

[mikey_d_13]

Thanks for all the info..ill go over it better wen I get home but the summit number for the kit I bought is cca-k68-231-4...check it out and let me kno if it will work

[mikey_d_13]

Ill have to look for tje spacer to buy..my crank is already done and I want to start the assembly..how do I polish the pistons? Machine shop or can I do ir myself?

[dwg86]

Send the cam "k" kit back. You can't use the springs and retainers. Buy just the cam and lifters. You will have to use Mopar Performance springs and retainers, or call Hesco (www.hescosc.com) to see what springs and retainers they use.

Thanks for all the info..ill go over it better wen I get home but the summit number for the kit I bought is cca-k68-231-4...check it out and let me kno if it will work

[dwg86]

What year block are you using? If you are using the later style block with the camshaft retaining plate...you will need to buy a timing chain, bolt, spring and pin for the earlier style camshaft. As far as I know all performance cams are for the earlier 258 and 4.0 blocks.

[mikey_d_13]

Well why wont the springs and retainers fit? it says they will on the product info..
The block is a 96

[mikey_d_13]

What size are the 96 cheroee springs? These ones say 1.475 outside diameter

[dwg86]

The retainers fit the 258 valve which has a bigger diameter stem than the 4.0 valves(3/8 vs 8mm). The springs fit the retainers. The 258 use a 7 degree lock (which is what the inside of the retainer is cut for) and the 4.0 uses an 8 degree lock.

[dwg86]

If you call comp. they will verify that the springs and retainers won't fit the 4.0L.

[mikey_d_13]

okay well I called to verify and resolve the spring problem..now will the timing chain in the kit work?
And can I use stock retainers and locks?
Or should I order that from mopar too?

the mopar P5249464 springs will definitely work?
http://www.summitracing.com/parts/DCC-5249464/

Thanks by the way..you saved my butt on that one