Jeep Cherokee Forum - 4.5L stroker

Jeep Cherokee Forum (https://www.cherokeeforum.com/)

- Modified XJ Cherokee Tech (https://www.cherokeeforum.com/f67/)

- - 4.5L stroker (https://www.cherokeeforum.com/f67/4-5l-stroker-158873/)

Hi, I am going to pick up a spare 4.0 engine - nice to have laying around if my current one craps out.
I am playing with the idea of stroking it. I looked into a 4.5L and it seams like all I need is the 258 crank and rods, 4.0L pistons sealed power 677, and .51" head gasket stock, and that is it. Do i need to get the pistons dished out? Also I read that this set up will give me a 9.05:1 compression ratio is that true?

Quote:

Originally Posted by Borgli (Post 2231926)

Depends what combination of parts you use.

See Here:
https://www.cherokeeforum.com/f51/strokers-15710/
http://jeep4.0performance.4mg.com/stroker.html

Quote:

4.6L Low-buck, low CR "rockcrawler"

Jeep 4.2L 3.895" stroke crank
Jeep 4.2L 5.875" rods
Silvolite UEM-2229 +0.030" bore pistons
Increase piston dish volume to 30cc
8.75:1 CR
Crane #750501 192/204 degree camshaft
Ported HO 1.91"/1.50" cylinder head
Mill block deck 0.035"
Mopar/Victor 0.043" head gasket
0.058" quench height
Ford 24lb/hr injectors with stock 39psi FPR for '87-'95 engines, stock injectors with stock 49psi FPR for '96 and later engines
234hp @ 4500rpm, 311lbft @ 3300rpm

4.5L "Poor man's" simple stroker

Jeep 4.2L 3.895" stroke crank
Jeep 4.2L 5.875" rods
Sealed Power 677CP standard bore pistons
9.2:1 CR
Stock 4.0 camshaft
Ported HO 1.91"/1.50" cylinder head
Mopar/Victor 0.043" head gasket
0.088" quench height
Ford 24lb/hr injectors with stock 39psi FPR for '87-'95 engines, stock injectors with stock 49psi FPR for '96 and later engines
247hp @ 4900rpm, 300lbft @ 3500rpm

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 with adjustable FPR or MAP adjuster for '87-'95 engines, Ford 24lb/hr injectors with stock 49psi FPR for '96 and later engines
266hp @ 4950rpm, 322lbft @ 3500rpm

4.6L Low-buck stroker

Option 1: Same as above except:
Speed Pro H825CP +0.030" bore pistons
9.6:1 CR
Mopar/Victor 0.043" head gasket
0.081" quench height*
265hp @ 4900rpm, 325lbft @ 3500rpm

Option 2: Same as "rockcrawler" except:
Piston dish volume 22cc
9.5:1 CR
Crane #753905 204/216 degree camshaft
Ford 24lb/hr injectors with adjustable FPR or MAP adjuster for '87-'95 engines, Ford 24lb/hr injectors with stock 49psi FPR for '96 and later engines
262hp @ 4800rpm, 325lbft @ 3500rpm

Basicly I don't want to do any mashining or milling. Do I have to do that to adjust quench and whatnot?

You can lower your quench by running a thinner head gasket. But then you have to worry about compression being too high. Then you would need to dish the piston to enlarge the combustion chamber and lower the compression.

both the 4.5L options do not require dishing or milling. The head gasket thickness adjusts the quench height. The head should be ported or at least opened up regardless.

Search "poor man's stroker".

Quote:

Originally Posted by dukie564 (Post 2231938)

Depends what combination of parts you use.

See Here:
https://www.cherokeeforum.com/f51/strokers-15710/
http://jeep4.0performance.4mg.com/stroker.html

Ok, thanks.
I still dont understand quench hight though. On the "poor man simple stroker" they use a 0.043" head gasket, quench = 0.088. On the "low buck simple stroker" they use a 0.051 head gasket, quench = 0.081. Wouldnt the thicker gasket give a higher quench, 0.096?
My math, 0.043 = 0.088 and 0.051-0.043=0.008. Quech: 0.088+0.008=0.096.
Does a higher quench number equal less space between head and cylinder or does it mean something else.
What is stock quench?

Quote:

Originally Posted by dukie564 (Post 2234727)

Read: http://www.jeepstrokers.com/forum/vi....php?f=34&t=73

Quench is the distance of the Flat surface of the piston, at TDC (Top Dead Center) and, the same flat surface of the head. You need a minimum of 0.043 of quench.

Stock deck clearance is 0.0215".

I'm not sure how that writeup calculated quench, but I always thought it was deck clearance + HG thickness also...

Ok so I just picked up the engine. It's in a good condition with 118 000 miles on it. There is some rust inside where the coolant flows though. Is there a good way of cleaning that? Some kind of home acid tratment for just the cooling system?

i'd imagine you could use CLR if the engine is disassembled. Just make sure you rinse it all out.

Would all the torque specs be the same during assembly? Looking into this myself because my engine is on its way out.

Quote:

Originally Posted by peter93xj (Post 2242160)

Would all the torque specs be the same during assembly? Looking into this myself because my engine is on its way out.

Yes.

My progress on the 4.6 as of last night: