Stock replacement camshaft

[IH 392]

Last week the distributor drive gear in my Wrangler took a big O'l sheit, so needing to get my Jeep back on the road sooner than later I'm just going to patch it back together, I opted for the Melling #MC1376 stock replacement cam for the '96-'99 4.0, just looking at it you'd swear it was an OE Chrysler cam!? it's ground on a "CWC" blank, no identification what so ever, it has NO fuel pump eccentric and it has the WIDE lobes!, I'll post back later on how well the distributor indexes?
As this appears to be a quality part I thought I'd let you guys and gals know, also this cam actually compares rather well to the Mopar Performance cams rather well on the dyno simulations!, more horse power but a little less torque.

[herbiehind]

thanks very much . looking forward to your report .

[Missourian]

Thanks for this post.

[IH 392]

It's coming along SLOWLY!, when I got into the engine it was hurt worse than I thought!, before I found all the issues I destroyed the gear on my spare distributor! , I've got a "CROWN" replacement gear so the "indexing" may very well out the window? I found the oil pump drive shaft broken in half! I can't confirm it yet but I believe the issue is with the Melling oil pump to 4.0 block interference? that SilverXJ posted up about here http://www.jeepstrokers.com/forum/viewt ... =34&t=2671 , my new block does indeed have the issue and will be corrected!
The new block is sitting there at .020 over with the new ICON KB944's sitting on top, and my 12 CW crank is ground and balanced along with the new clutch and reconned flywheel, I've got to build a fixture to balance my rods then I can check the deck, and I haven't decided what I'm going to do with the head?, just grind the valves on my 0630 head?, or put my Chivy LS1 valves in my 7120 head?
I need to get of'n my lazy azzs!

[SilverXJ]

The cam is interesting. I wonder why more aftermarket suppliers don't use that blank with the wide lobes vs. the narrow lobes.

On the oil pump drive, the distributor shaft not being inline with the oil pump drive could cause it to break. You also may want to make sure that the distributor shaft doesn't bind/bottom out on the oil pump shaft. I haven't heard of the issue on these engines but on some V8 engines the drive may need to be spaced. Since the gear on the dizzy was damaged there is a possibility that the oil pump was binding, causing the wear and snapping the shaft. maybe if the misalignment was bad enough the shaft could have been binding on the block. What year is your block that you have the interference issue on and which melling pump has the interference? I'm really surprised that that issue was never mentioned before.


As for the head, if your valves are ok you can just go with a 3 angle valve job, perhaps back cut the valves 32* as well. Another option is to use Dodge Magnum (5.2/5.9L) valves. They are close to the same size and can be had in swirl polished stainless for much less than the same for the Jeep head. I wouldn't go with the Chevy valves as they are quite larger and heavier (IIRC). The engine will not benefit from a larger head on the valve not will increased weight help. There is one advantage though. If you need your valve guide redone they can be simply opened up to accommodate the larger valve stem.

[IH 392]

The damaged one is the '97 block with a Melling M81 oil pump, the OE aluminum pump went fruity about 4 years ago, I had the new Melling pump and went and got a new pickup and simply installed it, the clue that it went was the oil SLICK under my Jeep!, upon investigation I found the distributor moving around in a circle while the engine was running, the oil pump shaft broke one of the ears off so I don't wonder if it had been working all the time? I don't believe the shaft was touching the block until it broke?
The new pump is also a Melling M81 and the new block is an'00.

The LS1 valves have 8mm stems so there is no work there and they are the small ones at 2.00" intake and 1.55" exhaust, and they are quite "tuliped" that will help bring the compression back down, working over my 7120 head will only cost my time, I have all the equipment (OLD! school) to do it, I'll see about the weights of the valves, I have my scale set up now to weigh my rods and pistons.

[cruiser54]

FWIW, I installed a replacement distributor into my son-in-law's 4.0 due to the sync generator being bad and the fact that it was old and original. Upon start-up I noticed that the dizzy had a little wobble to it. It turns out the dizzy shaft was a bit too long not allowing it to seat fully. Fixed it on the bench grinder by shortening the tang on the bottom of the dizzy shaft.