Camshafts that work

[mendelmax]

Hi guys.

I thought there is a need to write, which cams do work, and which don't with our strokers. Especially since some manufacturers write "not for fuel injection", like CompCams does.

I mean purely the ECU aspect, because obviously different setups need different camshafts. So my idea is that everyone here could write which cam did they use and whether they had any problems/ trouble codes or not. I also think that the rod length is important factor here, and of course the OBD type, so we should add it too. We could then include it all into a FAQ or something.

I personally am really interested with the 68-201-4 cam, if someone has it please let me know.


So, starting with me, the obvious:

Clevite 229-1929 (same as stock for 91-95) with 4.2 rods works with no problems for OBD I

[mendelmax]

Over 50 thread views and noone answered? Guys, come on

[SilverXJ]

Comp cams 68-232-4 w/ stock 4.0L, and then 4.6L short rod (4.2L) stroker. Worked fine
Comp cams 68-231-4 w/ 4.6L short rod stroker and now 4.6L 4.0L rod stroker. Works fine. Only thing i notice is a slight misfire on idle, but I am working on getting that out.

All on my 2000 XJ.

[dwg86]

I'll let you know how my engle cam works(213 [email protected], 501 lift, 112 lobe sep., 109 intake centerline). Maybe installing stroker next week(2003 TJ).

[gradon]

Mopar P4529230ab cam 256* adv dur. in/ex .45" lift 108* centerline works good on obd2s(-17inHg at idle on mine).

[RAPTORFAN85]

I should have my engine back up and running in a couple weeks with the 68-201-4 cam in it. Just need to find the time to put it together

[lafrad]

"Not for fuel injection" is just them covering their butts...

Carbs take a cam swap easy... just twist the idle screw and it at least runs.

FI relies on the idle vacuum to be within a specific range to be able to apply fuel appropriately.
higher LSA and longer durations mess that range up and can cause idle to suck.


If you have a map adjuster and/or stroker, that REALLY changes the situation. I bet most offered cams from any of the companies that are labled "Street/Strip" or less aggrgessive will work fine with a 4.6 or bigger and a simple map adjuster.

[mendelmax]

Thanks guys

If you have a map adjuster and/or stroker, that REALLY changes the situation.

Yeah, I guess you are right. The engine displacement itself helps with vacuum anyways. And these angles are not so much off compared to stock. I thought that it may also be associated with the intake centerline, to trigger the injector in the right moment, but on the other hand, these aggressive cams stay above stock lift height longer, so I guess there won't be any problem with injector "shooting" into closed valve.

[SilverXJ]

Thanks guys

If you have a map adjuster and/or stroker, that REALLY changes the situation.

Yeah, I guess you are right. The engine displacement itself helps with vacuum anyways. And these angles are not so much off compared to stock. I thought that it may also be associated with the intake centerline, to trigger the injector in the right moment, but on the other hand, these aggressive cams stay above stock lift height longer, so I guess there won't be any problem with injector "shooting" into closed valve.

Is there any way to determine when the injector is suppose to fire in relation to cam position? I know on my 00 it would be easy to adjust with just the cam sensor and no distributor to worry about.

[mendelmax]

Well, there is no distributor, but on the other hand, as far as I know the PCM also uses the camshaft sensor for proper spark timing. Not sure how though, since the main trigger for a spark is the crank sensor.

[SilverXJ]

The cam sensor just controls fuel synch, when the injector is suppose to fire. At least on my 2000. It would be nice to know when the factory thought it ideal to fire the injector. Then you could figure out where that exact point is when degreeing in your cam and set the sensor then.

[mendelmax]

If it's true and PCM uses it only to trigger the injector, then you are right, it may be great way to fine tune it.

I would bet, that the injection time is set at intake centerline, or just before it since this is the moment when most aggressive flow occurs, causing a lot of turbulence that mixes the fuel. I think it can be simply measured by rotating the crank on already mounted engine and observing on voltmeter when the pulse is sent.

[SilverXJ]

That wouldn't work because the PCM will only send the signal when the engine is running on its own power. You can't turn it over by hand and look for the pulse for the injector... plus if you did try to do that you may actually end up with some broke bones as it might start.

[mendelmax]

Well, I thought about doing it with spark plugs removed, to make turning it easier and avoid the possibility of startup. Are you sure that with ignition on it wouldn't send the pulse to the injectors?

[lafrad]

Injector timing is most likely able to be controlled as well as spark timing. within a degree or two of crankshaft rotation.

Thing is, on most pollution controlled motors, the injector timing is adjust to *finish* firing just a few degrees before TDC on the COMPRESSION stroke. This means, that for small pulsewidths, the fuel actually is fully injected on the closed valve. This allows for better atomization and a cooler intake valve. Only when load goes up does it get to spraying into the open vavle

With this in mind, the timing events of the camshift really have little effect on when the fuel is injected. it just doesn't matter.