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experiences with a mild camshaft upgrade??

Pete M

NAXJA Forum User
Location
S/E Michigan
What I'm working with is a 127K mile 88 4.0L that was stripped down to the head gasket for inspection and is sitting on an engine stand. This is going into my 88 MJ to replace the tired and leaky 186K+ mile 4.0L. I'm at the crossroads of whether or not to upgrade the camshaft. The cam never again be as available as it is right now. The block will be stock other than a Jacobs ignition, free-flowing airfilter/exhaust and whatever porting I can do to help match the gaskets. Oh, and the truck has a manual trans with 4.10s and 33s.
Questions:
-Exactly how hard is it to swap cams? It's a new procedure to me, but then again, so was replacing head gaskets until I did it to a friends Bronco last month. Any special tools?
-I'm assuming I'll get a kit that'll include new lifters and such. I was thinking about Clifford's 264 cam, but I don't have any real preferences other than low-end power is prefered. (The picture on that page is obviously wrong, but I also noticed that the kit doesn't include new bearings. Are bearings hard to install? They're not press-fit, are they?)
http://www.cliffordperformance.com/catalog/97-2891_clifford_cam_kit_1857257.htm
-Who here has upgraded their cam on a relatively stock engine? Which did you use and how much did you like it?
-Are there any online camshaft installation walk-throughs? My searches have come up with very little.
-And lastly, are there any more questions I should be asking?

Thanks and Jeep on!
--Pete
 
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Look up Dr. Dyno in the street/performance forum... he's very knowledgable about engine upgrades.
 
I don't want to double-post, but I bet he'll see this.
All the discussions I've found have been about strokers or otherwise highly modified engines. Mine is bone stock original and will stay that way (other than the cam kit of course). My funds won't allow what I truely want, but I don't want to pass up on this opportunity if it's something I can/should do. I just talked a bit with a guy at Cliffords and he says that installation is easy. But then he's trying to sell me something, so I can trust his word only so much.
Jeep on!
--Pete
 
complete rebuild of stock engine, .30 over. bought a comp cam 68-200-4 $225.00. (RV cam) a little more torque, a little less gas milage. there is a noticeable difference in torque. You will need to index your distibutor to make it work when you install a aftermarket cam in your 4.0. I ended up just grinding the tab off of the distibutor so that i could adjust a non adjustable distributor. timming is right on now. talk to the guy a your local machine shop. He should have stack of cam cataloges and "should" be able to help you with a cam that will suite you needs.
 
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You didn't state the most important facts.....is this going to be a daily driver? Do you wheel it? Rocks or mud? Low or high altitude?

A RV type cam will really improve your around town pep and trail pep but will most likely hurt your top end on the freeway. If the engine is on an engine stand. It is relatively straight forward. You pull off the timing chain cover on the front and remove the chain. Don't remember the exact method used to keep the cam in place but I think it will simply slide out the front if you have removed the lifters and distributor. Make sure and use new lifters. Lube the cam according to the manufacturers specs before starting and follow their breakin proceedure. Careful on cams with too high a lift as you may need to change springs if you go too extreme. While you have the cam out, replace the timing chain as a set. A cam is the best performance mod you can do for the most part. I'm running the Crane cam in my 4.7L stroker and love it.
 
Pete M said:
I don't want to double-post, but I bet he'll see this.

He he he, how did you know? ;)
Since your 4.0 is essentially going to stay bone stock (no reboring necessary?) with a stock 8.8:1 CR, I think the Crane 750501 cam (248/260 advertised duration) will suit your needs right down to the ground. The basic rpm range is 1000-4000rpm so there'll be plenty of torque for rockcrawling and for highway use. This cam starts to tail off from 4500rpm upwards but I don't think that'll concern you too much. You can get it from Summit Racing (part no. CRN-750501) for ~$200. You'll also need a set of Crane lifters. You could probably get away with using the stock valve springs with this cam since the lift isn't too high (0.427"/0.456").
Go to the Tech section of the Crane site for info. on correct installation. Since you have the engine on a stand, this'll be easy. I strongly advise that you get new cam bearings pressed in by a machine shop before installing the new cam. You'll need to remove the old cam first and that's straightforward. Remove the timing cover, remove the chain tensioner, remove the cam sprocket retaining bolt (don't lose the spring and thrust pin from inside the bolt), slide the oil slinger off the crank snout, and then slide both the cam/crank sprockets with chain as a unit.
Before you slide the cam out of the block, you'll need a lifter removal tool to remove the lifters first. Once that's done, you can slide the cam out from the front. When installing the new cam, make sure that you liberally coat the cam lobes and journals with the supplied assembly lube. You'll also need to coat the undersides of the new lifters.
Good luck with the build-up and let us know how it goes. :)
 
D'oh! I guess that would be kinda important, wouldn't it. :D It's a wheeler mostly, but I'm not afraid to drive it where ever I need to go (at least I was before she turned into the Exxon Valdez, leaving behind about a quart every 30 miles). If I had a job 2 hours away, I'd drive something else only to to keep the mileage on the old girl under control. I'm in S/E Michigan and most of what we have are muddy/dirty trails. There is the Silver Lake sand dunes park, but I'm certainly not going to build my truck for something I only do once a year. I couldn't care less how it performs on the freeway. I'd go get 4.88s *today* if I could afford it. Gas mileage is meaningless to me as long as the truck is performing properly (being below a certain mpg range presumes that something is wrong). It's been surprising to me, but I seem to actually prefer a slow-n-steady approach to wheeling rather than just mashing the gas pedal. Just the opposite of my on-road habits.
Clifford's kit comes with new lifters, springs, chromo pushrods, etc. for $360. Seems like quite a bit of cash, but I'd really prefer a matched kit rather than piecing together parts that I "think" will work in harmony. The 264 cam states it has a .474 lift with a .206 duration (.050) and 114* lobe centers (EFI model). http://www.cliffordperformance.com/catalog/97-2021camshaft_hyd__type_1710694.htm
The more I talk with people, the more they suggest a ton of other "while-you're-at-it"s. It all adds up really quick and I don't have the money for a rebuild, which is why I bought a whole truck that ran well (except for the bad Peugeot of course) for $350. It looks like I might have to figure out how to haul it over to a shop to get a firsthand opinion on its condition. If I only got another 20-25K miles out of it, I'd be satisfied. I'd just like to be a little *more* satisfied when I employ the happy-pedal. :D But I also don't want to screw anything up because of my torque greed.
Jeep on!
--Pete
 
Oops, you beat me by a few minutes there Doc. Guess I need to type faster.
I don't think it's ever been touched, but I'm no expert and I haven't peeked at the bottom end yet (I'll do that tonight). The cylinder walls are like glass with no marring at alll that I can find. Oh, and the rpm range of that Clifford cam is 2000-4500.
Does the two numbers 0.427"/0.456" mean it's a dual pattern cam? I'm still in the learning curve here. How does that compare to the single number of the Cliffords (.474)? Since the Cliffords is taller, is that why their kit includes new everything?
Jeep on!
--Pete
P.S. I'm taking lots of pics as I go and I'll probably have to create a whole new folder at my photo site to hold them all. :D

__________________
-89 Comanche; 4.0L, 2wd, now drivetrainless and waiting for its new owner to come pick it up
-86 Comanche; 2.8L, 4wd, AX-5, Metric tonne package with AMC-20 rear, now with a cap!
-88 Comanche; 4.0L, ex-2wd, '99 TJ ax-15/np-231, '78 Ford axles: Dana-44 w/spool and Warn premium hubs, 9" w/factory posi, both with the factory optional 4.10 gears!, stock Ford radius-arm front suspension, ~5.5" of lift, custom bumpers, 33" trXus M/Ts, etc.
Project pics: www.picturetrail.com/petermontie
Email: [email protected]
Comanche Yahoo group: http://autos.groups.yahoo.com/group/jeepcomanche/
 
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Pete M said:
Oops, you beat me by a few minutes there Doc. Guess I need to type faster.
I don't think it's ever been touched, but I'm no expert and I haven't peeked at the bottom end yet (I'll do that tonight). The cylinder walls are like glass with no marring at alll that I can find. Oh, and the rpm range of that Clifford cam is 2000-4500.
Does the two numbers 0.427"/0.456" mean it's a dual pattern cam? I'm still in the learning curve here. How does that compare to the single number of the Cliffords (.474)? Since the Cliffords is taller, is that why their kit includes new everything?

The Clifford kit has more items than you need. Like I said, you could probably get away with stock springs/retainers/locks and unless your pushrods are worn/damaged, you can reuse those as well.
The Crane cam that I mentioned is indeed a dual pattern cam (exhaust duration longer than intake), and that gives it a broader power band than the CompCams 68-200-4 that PETEY used. The Clifford 264 cam is probably too long in duration for your needs. You'll need more torque below 2000rpm for wheeling and the Crane 750501 will get you there.
 
PETEY said:
You will need to index your distibutor to make it work when you install a aftermarket cam in your 4.0. I ended up just grinding the tab off of the distibutor so that i could adjust a non adjustable distributor. timming is right on now. talk to the guy a your local machine shop

What does this mean? I did not have to do any such thing when I put in an after market cam. Timing seems perfect.

Petey, could you elaborate on this?
 
JeepSpeedRacer said:
What does this mean? I did not have to do any such thing when I put in an after market cam. Timing seems perfect.

Petey, could you elaborate on this?

Yeah, I didn't understand that comment either. I just removed the head and installed a new Crane cam in my engine, and didn't do anything to the distributor.

I agree.....if the head is already off of the engine, it's very simple (and inexpensive) to install a new cam.....I did it last weekend. My Crane cam was $109 from Summit Racing, and the lifters were less than $50 at the auto parts store. The only complication would be if you thought you should install new cam bearings because of the miles on the motor. I didn't because my motor only had 20k on it since it was stroked/rebuilt. I also went with Mopar Performance valve springs since the cam I used had more lift, which added nearly $200.

Finally, my motor will be in next weekend.........after I repair more frame cracks around the track bar/steering box.
 
Thanks for all your help guys!
Ok, except for Petey's timing thing, I think I'm getting a handle on this. One more thing I don't understand (thus far at least), the Crane cam states the duration as 248/260 while the Cliffords says 206 with .050 in parenthesis. What do I do with those numbers in order to compare them?
Oh, and I've got the oil pan off and the engine rotated upside down (if anyone here has never done that, make sure there's a pan underneath to catch any leftover oil and antifreeze). Is there a way to check if the cam bearings are good or not? All my experiences with bad bearings meant finding some noticable slop and the cam shaft is not moving at all.
Jeep on!
--Pete
 
sorry guys maybe it's not so common as i had thought. after the engine was installed, the thing would sputter right about 1900 rpms wouldn't so while pressing the gas or letting off of gas just at a steady 1900 rpms. I could not figure it out. I ended up taking it to a shop a couple of times and they couldn't figure it out either. ended up replacing parts I didn't need. I did some research and I believe I found the answer right here on NAXJA. the post was about indexing your distibutor. involves a sacraficial cap were you cut a viewing hole. and turn the distibutor where it needs to go. of course you can't do that on the 4.0 so I made it adjustable. you get it close then fine tune it. I figured that it was common with an aftermarket cam on 4.0 from the research I did. In fact there were several post that stated something to that effect. Anyway it did work and the engine runs smooth and strong. I didn't have to turn the distibutor very far at all though. just a little past from were the tab limits movement.
Like this, (found by searching)

Timing on the XJ is controlled by the CPS and is not adjustable.

Having said that, there was a factory tech bulletin back around '88 or '89 on "indexing" the distributor, which may (or may not) help you. Strictly speaking, this does not change the timing, because the point at which the ignition fires is still controlled by the CPS. However, if the distributor isn't indexed correctly, when the ignition fires the rotor isn't pointed at the right terminal on the cap, so you may get a weak spark.

The procedure is to take a sacrificial distributor cap (your old one is perfect for this, if you have it). Use a Dremel or similar small grinder to cut away the side of the cap to expose (but not remove or damage) the #1 turret and contact.

Remove the regular cap and install the modified one. Slowly rotate the engine (preferably by hand) until the #1 cylinder gets to TDC on the compression stroke. At TDC the tip of the rotor should be PAST (beyond) the #1 contact, with a gap of 0.020"

If your gap is significantly different from this, you have to remove the distributor, grid away the nubs that "locate" it, then reinstall and turn it manually to achieve the 0.020" gap, then tighten down the hold-down clamp.

Before you go through all this -- how's your oxygen sensor? When the O2 sensor on my '88 went bad, the first sign was an occasional soft, muffled "Pop" that sounded a bit like an intake backfire. It was actually unbruned fuel from an over-rich mix hitting the catalytic converter and exploding there. The O2 sensor is supposed to be changed at 75,000 to 80,000 mile intervals. If yours is close to that mileage -- or if you don't know -- I'd try a new O2 sensor.
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PETEY said:
sorry guys maybe it's not so common as i had thought. after the engine was installed, the thing would sputter right about 1900 rpms wouldn't so while pressing the gas or letting off of gas just at a steady 1900 rpms. I could not figure it out. I ended up taking it to a shop a couple of times and they couldn't figure it out either. ended up replacing parts I didn't need. I did some research and I believe I found the answer right here on NAXJA. the post was about indexing your distibutor. involves a sacraficial cap were you cut a viewing hole. and turn the distibutor where it needs to go. of course you can't do that on the 4.0 so I made it adjustable. you get it close then fine tune it. I figured that it was common with an aftermarket cam on 4.0 from the research I did. In fact there were several post that stated something to that effect. Anyway it did work and the engine runs smooth and strong. I didn't have to turn the distibutor very far at all though. just a little past from were the tab limits movement. Dang, now I'm wondering if I screwed up.

What you describe sounds like you were off by one tooth on the distributor, but no big deal, if you got it running, you just got the the same point by a different route.

Note: The little cast ear on the distributor is there only to index the distributor, not to hold it down. You still need to put the steel crow's foot clamp on the distributor. A buddy helped me put my engine back together and the didn't think it was necessary anymore and didn't install it. Twenty miles later the tang broke off and the distributor tried to launch through the hood. :repair: I now have a setup similar to yours but not on purpose :laugh3:
 
It was the first time I rebuilt a engine and learned a lot. The tab is what I cut. The clamp is intact and holding the distributor in place. Thanks Mr. Old Man. I think I'll go out, pull the distibutor, move a tooth, put it back where it's supposed to go, n see if it'l run.
 
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