1987-2006 Jeep 4.0L Inline Six - Stroker

11. We used 0.030-inch-oversize Sealed Power hypereutectic pistons (PN H802CP), which are a performance piston for 4.0L applications. In addition, the skirts are Teflon-coated to reduce friction. We measured an 18.83cc dish volume (including ring land). People get by with ordinary cast 4.0L pistons quite well also.
11. We used 0.030-inch-oversize Sealed Power hypereutectic pistons (PN H802CP), which are
12. You are best off with the '91-and-later high-output cylinder head. It flows better than the '87-'90 "low-port" head, though not by a massive amount. We used a '00 H.O. cylinder head (casting No. 0331). These aren't the best H.O. heads from a performance standpoint, because they have smaller exhaust ports. (Reportedly, the best H.O. heads come from '91 to '98, and have the casting numbers of 7120 and 0630.) From the flow bench numbers we've seen, the differences aren't huge. Overall, if budget is a concern, all the heads can be used effectively. A dual-pattern cam with longer exhaust duration really helps the 4.0L exhale.
12. You are best off with the '91-and-later high-output cylinder head. It flows better tha
13. For a timing chain, we went with the reliable Cloyes double-roller set. They last forever and have the option of making timing changes. The three options (see red arrows) are 4 degrees advanced, "straight up" (zero advance), or 4 degrees retarded. These options can be used to correct timing errors or for a specific tuning purpose. Advancing the timing enhances bottom-end performance at the expense of upper-end performance, and retarding the cam timing does the opposite. Bear in mind that the '00-and-later blocks use a different timing set. The Crane cam we used was set up for the earlier unit so the Cloyes was ordered to fit the earlier setup.
13. For a timing chain, we went with the reliable Cloyes double-roller set. They last fore

Part	Casting Number	Year	Note
Block	53005535	'87-90	Non-HO
Block	53008405	'91-95	HO, early
Block	53020569	'96-99	HO, late, best for pre-2000 Jeeps
Block	53010449	'99-06	HO, metric fittings
Crank	3199738	'71	Drilled for Borg-Warner automatic, bad pick
Crank	3214723	'72-80	12 counterweights, long nose, strong & heavy
Crank	3235477	'81-86	4 counterweights, long nose
Crank	3727	'87-90	4 counterweights, short nose, best pick
Con Rod	154	'64-66	5.875 length, 232ci, weak rod!
Con Rod	207	'64-79	6.125 length, 199 & 232ci, weak rod!
Con Rod	707	'71-81	5.875 length, best pick short rod
Con Rod	352	'82-90	5.875 length, ok
Con Rod	53020126	'87-06	6.125, 4.0L rod, best pick long rod
Cyl Head	2686	'87-90	Non-HO, Renix engine
Cyl Head	7120	'91-95	HO, good pick, 55.22-58-22cc
Cyl Head	0630	'96-99	HO, good pick, 55.22-58-22cc
Cyl Head	0331	'99-06	HO, so-so pick, 55.22-58-22cc
Piston	-	'87-06	4.0L, 1.60 pin height, 13.5cc dish
Piston	2229c	-	Keith Black, 1.58 pin ht, 11.5cc dish
Piston	677CP	-	Sealed Power, 1.592 pin ht, 17.5cc dish
Piston	H802CP	-	Sealed Power, 1.585 pin ht, 17.5cc dish

Bold text indicates the parts used in the UNO buildup.

To Get Deck Height (DH)
deck height = block height* - rod length - piston pin height - 1/2 stroke

To Get Compression Ratio (CR)
CR = total cylinder volume combustion chamber volume

To Get Combustion Chamber Volume (CCV)
CCV = cyl head volume + head gasket volume + deck clearance volume + piston dish volume

To Get Cylinder Volume (CV), Deck Clearance Volume or Head Gasket Volume
CV = 0.7853942 x bore2 x stroke
Note: For head gasket, used compressed distance.

To Get Quench Height (QH)
QH = deck height + head gasket compressed distance
*Block height = Distance from crankshaft centerline to block deck On a 4.0L= 9.450-9.456-inch

SOURCES
ARP 531 Spectrum Circle Oxnard CA 93030 805-278-7223	KB-Silvolite Performance Pistons www.kb-silvolite.com
Crane Cams 530 Fentress Blvd. Daytona Beach FL 32114 3-86/-252-1151 N/A www.cranecams.com	Mopar Performance Mopar.com
Custom Design Performance www.cdpautomachine.com	Quadratec 8-00/-745-2348 quadratec.com
Golen Engine Service 17 Dracut Rd. Hudson NH 03051	Sealed Power
Hesco	University of Northwestern Ohio