Doing the typical replace worn out 4.0 with mild reliable stroker. The block I started with is a 1990 renix block, during disassembly a buddy knocked the factory cam off the work bench and the main bearing surface is toast from hitting the concrete.
When it comes to replacement I want to stay OEM since I will be keeping the obd1 ecm in my 91 Comanche (reworking my head for this build as well). From researching the later model cam is supposed to produce more power and torque but by all of my research it seems like the early 90s cam would make more/better power based purely on the numbers and what I have read on cam selection. Is the single vs dual pattern what makes the difference and I am just not getting it right?
Any input from you guys or am I really just splitting hairs here.
Duration @ 0.050" lift int./exh.: 197.0/197.0 deg
Valve lift int./exh.: 0.424"/0.424"
Lobe separation angle: 112 deg
Intake centerline angle: 120 deg
Valve overlap (advertised): 46 deg
IVO: 21.5 deg ATDC (0.050" lift)
IVC: 38.5 deg ABDC
EVO: 22.5 deg BBDC
EVC: 5.5 deg BTDC
The stock '96 and later Jeep 4.0 camshaft is a dual pattern cam that produces more torque at lower rpm and a wider torque spread. The specs are as follows:
Advertised duration int./exh.: 256.0/260.0 deg
Duration @ 0.050" lift int./exh.: 188.0/192.0 deg
Valve lift int./exh.: 0.408"/0.414"
Lobe separation angle: 107 deg
Intake centerline angle: 114 deg
Valve overlap (advertised): 43 deg
IVO: 20 deg ATDC (0.050" lift)
IVC: 28 deg ABDC
EVO: 16 deg BBDC
EVC: 4 deg BTDC
Finishing research and parts list.
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Re: Finishing research and parts list.
Is there a reason why you’re limiting your choices to a stock Camshaft?
Unless it’s for a cost considerations, stock camshafts are fine for stock engines but will limit the potential in your stroker build.
Cam manufactures will not always be honest with you, but the leading reason why they make single pattern camshafts is because it’s simpler and more economical to grind.
If you logically think about it, a internal combustion engine requires different characteristics in both lift and valve timing between the intake and exhaust cycles.
Unless it’s for a cost considerations, stock camshafts are fine for stock engines but will limit the potential in your stroker build.
Cam manufactures will not always be honest with you, but the leading reason why they make single pattern camshafts is because it’s simpler and more economical to grind.
If you logically think about it, a internal combustion engine requires different characteristics in both lift and valve timing between the intake and exhaust cycles.
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Re: Finishing research and parts list.
You don't need to limit yourself to the stock camshaft. Since the 4.0 head has relatively poor exhaust port flow compared to the intake side, it benefits from having a dual pattern cam with a longer exhaust valve opening duration and higher exhaust valve lift.
You could reduce the cost by opting for a camshaft with no more than 0.45" valve lift. This would allow you to retain the stock valve springs/retainers/keepers. Russ has a modified version of the CompCams 68-232-4 cam that would suit your needs perfectly.
You could reduce the cost by opting for a camshaft with no more than 0.45" valve lift. This would allow you to retain the stock valve springs/retainers/keepers. Russ has a modified version of the CompCams 68-232-4 cam that would suit your needs perfectly.
1992 XJ 4.6 I6 - 5MT - Stroker build-up, Stroker "recipes" Sold
1995 Mustang GT - 4AT - Modded Sold
2006 Mustang GT - 5MT - Modded Midlife Crisis Car
1995 Mustang GT - 4AT - Modded Sold
2006 Mustang GT - 5MT - Modded Midlife Crisis Car
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- Posts: 3
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- Stroker Displacement: 4.6
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Re: Finishing research and parts list.
Been meaning to shoot Russ an email about pistons anyways. Might get around to it this week finally.
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