Camshaft duration compatibility on Renix 4.0l

[Wild Comanche]

This is an update on an old post of April, 29, 2016.  I have an '89 Comanche.  It has a completely rebuilt '92 block and head.  The original Renix system is still being used.  In the last thread the question of flywheel compatibility has been addressed and answered. The engine does have the old Renix flywheel.  It idles good, but won't accelerate good.  On the rebuild, an RV camshaft was installed.  So it no longer has the original camshaft grind.  Could this be a problem with the old Renix computer system?  Could it be that the Renix computer can't pick up on the different timing on when valves are opening and closing?  Any input on this subject will be greatly appreciated.  Thanks for all the input in the past. 

[Marine1Texas]

If you have a cheap HEI dizzy to drop in, you could test against the ECU. I run HEI on my 87 4.0 with HO head, on my 87 The ECU only controls the fuel injection. on my 88 that is a 4.6L I use no ECU at all HEI with carb setup.

[DirtyComanche]

Was the cam timing set correctly? It should not be a radical enough cam for the computer to care.

[Eagle]

The ECU has no idea when the valves open and close. The valves are controlled mechanically by the camshaft, there is nothing electronic about it.

 

Is it possible that your expectations are unreasonable? An "RV" camshaft is designed for low RPM grunt pulling power, not for drag racing. It produces low-end torque, but not high end horsepower. If you're looking for sports car performance, you may have picked the wrong cam grind.

[cruiser54]

Did you index the distributor per my Tip 13? 

[DirtyComanche]

Is it possible that your expectations are unreasonable? An "RV" camshaft is designed for low RPM grunt pulling power, not for drag racing. It produces low-end torque, but not high end horsepower. If you're looking for sports car performance, you may have picked the wrong cam grind.

 

I suppose "won't accelerate good." is rather subjective.  I'm assuming he means it isn't going anywhere...  But if it's not seat in the pants better than a normal ol' Renix, I wouldn't be surprised.  Using the Renix TB, I believe that's probably the major restriction.  And there might not be much/any real gain in the higher end using the HO head/aftermarket cam when coupled with the Renix intake.

 

It's a truck motor, not a race engine.

[Wild Comanche]

Thanks for the comebacks.  The distributor has been indexed.  When I say the acceleration is not good, I mean parked in neutral.  It stumbles and misses.  It has the 1999 intake and a 60mm bored throttle body. So the intake system is far from stock 1989 Renix.  22lb. @ 39 p.s.i. injectors.  Exhaust headers with a low restriction muffler.   Fuel pressure at the rail of 39 p.s.i..  My old original engine with 267,000 miles could run circles around this new one.  The grounds have been checked.  It almost seems like a timing problem.  It's a head scratcher.

[cruiser54]

When you say indexed, do you mean you used my Tip 13? 

[HOrnbrod]

Which "RV" cam did you use? There are several mfg's for these and they have different lift specs. They are not all cut for low-end torque; some are cut for more mid-range. Hesco, Crane, Clifford, and several others all manufacturer what could be called "RV" cams.

 

For instance I run a Hesco RVOB single pattern cam with a duration of 214* @ 0.050" intake and exhaust, valve lift 0.470" intake and exhaust, and a LSA of 110*. This makes for a lopey idle (that I don't mind) and good mid-range "grunt". It also likes a non-restrictive 2.5" exhaust exhaust. Same injectors and intake as you have, but it's OBD1.

 

Some folks love the Crane 753905 dual pattern RV-type cam. The idle quality is the similar to stock in a stroker and it makes more low end torque. Bottom end is strong and lifespan is short on these cams from what I read.

 

So the point is you can't lump "RV" cams into one category. Each has their own characteristics and affect idle and peak HP/Torque specs differently. All the mechanical stuff has to be coordinated along with a good profile matched to the intake and exhaust, or you just don't get best power. That's why I bought a proven crate stroker engine and added the peripherals based on valid dyno results. I'm not smart enough or experienced enough to figure it all out from scratch.  :yes:

[Wild Comanche]

Thanks for the info..  The problem with the engine stumbling and missing has been solved.  When the engine was rebuilt I bought a set of new Ford XF2E-C4B 4-hole injectors.  To use them with the old EV1 connectors on the wiring harness I bought a set of adapters to go from EV1 to EV6.  Well these adapters were the kind that the male to female connectors were not one piece but separated with two wires.  They must have been poor quality as they were not making a solid connection all the time.  So now the engine runs like it should.  It was missing because it wasn't getting fuel.  Since this is the first time since it was rebuilt that I could actually drive the vehicle I have discovered something with the rebuilt auto 4-spd tranny.  The guy that rebuilt it builds trannys up for drag racing, every day drivers and in between.  I asked him to build it so it would last a while.  When it is put into drive, it is necessary to rev the engine up to 1100 rpms to get it to engage into first gear.  Even after it shifts into 3rd gear and speed gets to 25 to 30 mph if the rpms drop below 1100 it goes back into neutral.  With reverse this problem doesn't exist.  And it engages like a factory transmission.   I don't know if this is a good thing?  Might be a little hard on u-joints.  And just the driveabilty overall.  Any ideas?  The tranny's fluid level is up to where it should be.  Thanks for all the feedback.................

[HOrnbrod]

AW4? If so it sounds like the throttle valve is broke or mal-adjusted. Try this:

 

http://www.allpar.com/SUVs/jeep/cherokee-transmission.html

 

http://www.lunghd.com/Tech_Articles/Transmission_and_Transfer_Case/Transmission_Throttle_Cable_Replacement.htm

[Wild Comanche]

Yes it is the AW4 tranny.  Thanks for the adjustment tip.  I hope that is the problem...........

[Wild Comanche]

Well even after adjusting the transmission throttle cable the condition persists.  Not shifting into 1st gear at idle speed.  And when cruising at 25 or 30 mph coming out of gear when rpms drop below 1100.  The transmission builder thinks the pressure pump got too hot with a low fluid level or the forward clutch pack got really worn.  So there just isn't enough pressure being created by the pump.  And the reason it works in reverse is because it has a booster pump for reverse gear.  Either way not great news.  The throttle cable coming from the transmission is not the stock 1989 cable as a newer throttle body (1996) is installed.  He was wondering if the cam on the transmission would need to be changed with the different throttle cable as it might not be compatible with the newer throttle body as versus the old Renix throttle body.  Something I never thought of in the mix of the conversion.  The good news is that the engine runs really strong and smooth, but you can't go anywhere w/o a transmission. 

[HOrnbrod]

Well even after adjusting the transmission throttle cable the condition persists.  Not shifting into 1st gear at idle speed.  And when cruising at 25 or 30 mph coming out of gear when rpms drop below 1100.  The transmission builder thinks the pressure pump got too hot with a low fluid level or the forward clutch pack got really worn.  So there just isn't enough pressure being created by the pump.  And the reason it works in reverse is because it has a booster pump for reverse gear.  Either way not great news.  The throttle cable coming from the transmission is not the stock 1989 cable as a newer throttle body (1996) is installed.  He was wondering if the cam on the transmission would need to be changed with the different throttle cable as it might not be compatible with the newer throttle body as versus the old Renix throttle body.  Something I never thought of in the mix of the conversion.  The good news is that the engine runs really strong and smooth, but you can't go anywhere w/o a transmission. 

 

Could very well be this. The Renix and HO AW4 transmissions use different throttle valve cams.

 

CAM PACKAGE, Throttle Valve

87-90        83504338

91-01        4637026

 

Good luck finding the newer cam package. Since the pump is fried and may have taken out other hydraulic parts with it, you might be better off replacing the tranny with a 91 and up AW4.

[DirtyComanche]

Since the pump is fried and may have taken out other hydraulic parts with it, you might be better off replacing the tranny with a 91 and up AW4.

 

 

He will probably need a transfer case with a 23 spline input if he goes that route, or to swap the input gear over (but it has to be a 94~ or older gear since the gear pitch changed).

 

But I agree, I would replace the whole trans.

[HOrnbrod]

He will probably need a transfer case with a 23 spline input if he goes that route, or to swap the input gear over (but it has to be a 94~ or older gear since the gear pitch changed).

 

But I agree, I would replace the whole trans.

True - forgot about spline count. I know the AW4 output count changed to 23 in 1990, but what about the input?

[DirtyComanche]

 

He will probably need a transfer case with a 23 spline input if he goes that route, or to swap the input gear over (but it has to be a 94~ or older gear since the gear pitch changed).

 

But I agree, I would replace the whole trans.

True - forgot about spline count. I know the AW4 output count changed to 23 in 1990, but what about the input?

 

 

I don't believe there is any issues on the other end of the trans, it should just bolt up, make sure to use the flex plate that goes with the engine or the CPS won't work right.  IIRC, YMMV, I've never done it.  The AW4 did go through a few changes though.

[gogmorgo]

http://www.naxja.org/forum/showthread.php?t=1053970

Should cover any swap questions you have.

Use the flexplate that goes with the engine control system. Renix or HO.

[Wild Comanche]

Thanks for the advice.  I checked out the Cam Package #4637026 availability and it was discontinued in 2/09.   So as you said "hornbrod" it would be a long shot locating one of them.   I checked your link to "NAXJA" - alot of good info. there.  Thanks, "gogmorgo".  Since getting a correct cam for the AW4 just about entails picking up a used 1991 to 1994 transmission I can see your suggestion of using one instead of the 1989 AW4.  Should be some of that year model 4x4 AW4's in wrecking yards somewhere.   Looks like one difference in the different AW4's is the overdrive gear ratio.  And changing the output gear with the 23 splines back to 21 splines so it will mesh with the transfer case.  And then I could keep the original transfer case.  

[DirtyComanche]

Personally I would change the input gear on the tcase before I tore the transmission apart to change the output.  But I have played the parts swapping game in many of the NP/NV aluminum tcases and can do it quickly without running into problems.  The 23 spline setup is also way more common in general, so it would be easier to source later if anything else goes wrong.  But that's me.  I actually had such an excess of NP/NV tcases and parts that I threw a bunch of stuff out.

[Wild Comanche]

It has been a while, but the transmission probem has been fixed.  I couldn't locate one of the newer H.O. throttle valve cams anywhere for sale.  Ended up taking one out of a junkyard '93 AW4.  The guy that rebuilt the transmission tore the transmission down and found that a pin that held in a pressure plug had come out.  He said it was dumping 50% of the pumps pressure into the pan.  He guarantees his work, so did the second rebuild for free.  He said he has never encountered that problem before.  Kept the '89 AW4 and it works fine now.  Rebuilt engine and rebuilt tranny seem to perform well.   Thanks for all the input. 

[mikekaz1]

 

Well even after adjusting the transmission throttle cable the condition persists.  Not shifting into 1st gear at idle speed.  And when cruising at 25 or 30 mph coming out of gear when rpms drop below 1100.  The transmission builder thinks the pressure pump got too hot with a low fluid level or the forward clutch pack got really worn.  So there just isn't enough pressure being created by the pump.  And the reason it works in reverse is because it has a booster pump for reverse gear.  Either way not great news.  The throttle cable coming from the transmission is not the stock 1989 cable as a newer throttle body (1996) is installed.  He was wondering if the cam on the transmission would need to be changed with the different throttle cable as it might not be compatible with the newer throttle body as versus the old Renix throttle body.  Something I never thought of in the mix of the conversion.  The good news is that the engine runs really strong and smooth, but you can't go anywhere w/o a transmission. 

 

Could very well be this. The Renix and HO AW4 transmissions use different throttle valve cams.

 

CAM PACKAGE, Throttle Valve

87-90        83504338

91-01        4637026

 

Good luck finding the newer cam package. Since the pump is fried and may have taken out other hydraulic parts with it, you might be better off replacing the tranny with a 91 and up AW4.

 

 

 

:dunno:  I have a renix AW4 in my HO truck  and I have no TV cable issues..... and my internet works great too! :thumbsup:

[DirtyComanche]

 

 

Well even after adjusting the transmission throttle cable the condition persists.  Not shifting into 1st gear at idle speed.  And when cruising at 25 or 30 mph coming out of gear when rpms drop below 1100.  The transmission builder thinks the pressure pump got too hot with a low fluid level or the forward clutch pack got really worn.  So there just isn't enough pressure being created by the pump.  And the reason it works in reverse is because it has a booster pump for reverse gear.  Either way not great news.  The throttle cable coming from the transmission is not the stock 1989 cable as a newer throttle body (1996) is installed.  He was wondering if the cam on the transmission would need to be changed with the different throttle cable as it might not be compatible with the newer throttle body as versus the old Renix throttle body.  Something I never thought of in the mix of the conversion.  The good news is that the engine runs really strong and smooth, but you can't go anywhere w/o a transmission. 

 

Could very well be this. The Renix and HO AW4 transmissions use different throttle valve cams.

 

CAM PACKAGE, Throttle Valve

87-90        83504338

91-01        4637026

 

Good luck finding the newer cam package. Since the pump is fried and may have taken out other hydraulic parts with it, you might be better off replacing the tranny with a 91 and up AW4.

 

 

 

:dunno:  I have a renix AW4 in my HO truck  and I have no TV cable issues..... and my internet works great too! :thumbsup:

 

 

How did you route it?  The Renix cable is 6" shorter or so.  I'm running a HO intake/TB with Renix controls and tranny, I made it work but I had to cut up the brackets and some other creative nonsense.

[mikekaz1]

 

 

 

 

 

 

Well even after adjusting the transmission throttle cable the condition persists. Not shifting into 1st gear at idle speed. And when cruising at 25 or 30 mph coming out of gear when rpms drop below 1100. The transmission builder thinks the pressure pump got too hot with a low fluid level or the forward clutch pack got really worn. So there just isn't enough pressure being created by the pump. And the reason it works in reverse is because it has a booster pump for reverse gear. Either way not great news. The throttle cable coming from the transmission is not the stock 1989 cable as a newer throttle body (1996) is installed. He was wondering if the cam on the transmission would need to be changed with the different throttle cable as it might not be compatible with the newer throttle body as versus the old Renix throttle body. Something I never thought of in the mix of the conversion. The good news is that the engine runs really strong and smooth, but you can't go anywhere w/o a transmission.

Could very well be this. The Renix and HO AW4 transmissions use different throttle valve cams.

 

CAM PACKAGE, Throttle Valve

87-90 83504338

91-01 4637026

 

Good luck finding the newer cam package. Since the pump is fried and may have taken out other hydraulic parts with it, you might be better off replacing the tranny with a 91 and up AW4.

 

:dunno: I have a renix AW4 in my HO truck and I have no TV cable issues..... and my internet works great too! :thumbsup:

How did you route it? The Renix cable is 6" shorter or so. I'm running a HO intake/TB with Renix controls and tranny, I made it work but I had to cut up the brackets and some other creative nonsense.

I just ran it over the valve cover in a kind of diagonal. Not perfect but completely usable. Its a little annoying doing oil changes as it runs pretty much over the fill. But theres still enough slack to push it aside. Amd I don't drive it more then 2 or 3 thousand miles a year so its not often enough to bother me