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camshaft issues

Bmarsh

NAXJA Forum User
Location
Grand Haven, MI
Hi I am rebuilding my 4.0l out of my 99. The issue I am running into is that my stock cam is junk. I can find after market cams for pre 97 but none for late models. The other question is if I can get a performance cam will it be worth it as I only have a .030" bore and a thinner head gasket with bolt one such as intake and exhaust.
Thanks for the help,
Brandon
 
I've read that all the aftermarket cam manufacturers use lobes that are more narrow than the lifters and this coupled with higher spring rates is suspected to cause premature cam failure. Unless I get some better info that contradicts this my intention is to back with stock mopar cam when I rebuild/stroke my 4.0l. Hopefully someone here can provide more info.
 
Thanks for the help you guys. So the mopar cam should work perfectly for my 99 (fitment wise and performance)? If that's the case then I found my winner. Also with this cam can I run stock valve springs?
 
You can get a stock replacement cam from Melling or Engine Tech. Melling MC1377 or Engine Tech ES242 will go in just like stock. http://www.ebay.com/itm/Melling-MC1...Parts_Accessories&hash=item4d035bf5ec&vxp=mtr

If you want to go with an earlier style camshaft you will need to use the earlier style timing set, cam bolt, pin and spring. Of course you will need new lifters, which I recommend Johnson-Hylift p/n 2011.

In theory the wider lobes will prevent wear as there is more area for the lifter's taper.
 
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I've read that all the aftermarket cam manufacturers use lobes that are more narrow than the lifters and this coupled with higher spring rates is suspected to cause premature cam failure. Unless I get some better info that contradicts this my intention is to back with stock mopar cam when I rebuild/stroke my 4.0l. Hopefully someone here can provide more info.

Poor quality material used for the cam blanks, poor surface hardening of the lobes/journals, and poor quality lifters probably also contribute to the many flat-tappet cam failures we've seen in recent years.
Most of the aftermarket Jeep cams have lobes that are only 1/2" wide, whereas stock replacement and Mopar Cams have 2/3" wide lobes and more surface area for the lifters to ride on. If you couple the latter with stock valve springs you'll reduce the probability of cam failure.
 
I think the mopar purple cam is only good (fitment-wise) through '97, because yours is a '99 you'll need to use the the melling or engine tech stock replacement models Talyn suggested unless you follow the steps he suggests below.


You can get a stock replacement cam from Melling or Engine Tech. Melling MC1377 or Engine Tech ES242 will go in just like stock. http://www.ebay.com/itm/Melling-MC1...Parts_Accessories&hash=item4d035bf5ec&vxp=mtr

If you want to go with an earlier style camshaft you will need to use the earlier style timing set, cam bolt, pin and spring. Of course you will need new lifters, which I recommend Johnson-Hylift p/n 2011.

In theory the wider lobes will prevent wear as there is more area for the lifter's taper.
 
I haven't had any problems with the Mopar P4529230AB cam and the lifters it came with in 4+ years of hard driving. The stroker did chew up a stock single timing set by Federal Mogul/Sealed Power though. I do like the design of a retention plate instead of the pin and spring set-up, however. The P4549228A_(B-D depending what run of mfg) has the same amount of lift as the 87-95 cams, .43", but has 24* of overlap instead of the stock's 46*, so the dynamic compression is higher and low-end torque will be as well(great cam for boost). The P4549229A_ has .44" lift and 32* of overlap. Both of these cams come with lifters and can be used with the stock valve-springs.
 
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I haven't had any problems with the Mopar P4529230AB cam and the lifters it came with in 4+ years of hard driving. The stroker did chew up a stock single timing set by Federal Mogul/Sealed Power though. I do like the design of a retention plate instead of the pin and spring set-up, however. The P4549228A_(B-D depending what run of mfg) has the same amount of lift as the 87-95 cams, .43", but has 24* of overlap instead of the stock's 46*, so the dynamic compression is higher and low-end torque will be as well(great cam for boost). The P4549229A_ has .44" lift and 32* of overlap. Both of these cams come with lifters and can be used with the stock valve-springs.


Even though the mopar cam has more lift at .430 with 1.6 rockers, the advertised duration is 240/240 deg, compared the stock 96-01 cam advertised duration which is 256/260 deg. If you add 1.7 rockers, correct me if I'm wrong, I think the lift will be .433/.450 compared to the mopar cam with stock rockers, which is .430/.430. Anyways, does the dual pattern cam design that favors the exhaust side better for the 4.0?
I know the yella terra 1.7 rockers are almost double of what the cam costs, but the labor charges or the amount of labor involved in changing the cam won't be worth it, unless you have to tear down the engine for some other reason or that the stock cam is worn or the lifters are messed-up or that you need to change the timing chain. Even though, I'm not sure if the stock valve springs, especially if your engine has high mileage (mine has 159,100), can take the extra oomph from the higher ratio rockers.
 
Well I'll be installing my 1.7's soon on my '99 with stock cam. I've got high mileage, so we'll see how it does.

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Just as previously stated an aftermarket cam such as the mopar performance one doesn't improve over the late model stock 4.0 cam. So will it be in my best interest to just go with a stock cam. That way I don't have to worry about the plate/ pin mess for hardly if any performance gains?
 
Just as previously stated an aftermarket cam such as the mopar performance one doesn't improve over the late model stock 4.0 cam. So will it be in my best interest to just go with a stock cam. That way I don't have to worry about the plate/ pin mess for hardly if any performance gains?


Yeah. Basically, just go with the stock replacement if you don't want to go through the plate/pin mess. Even though I've read decent results with the mopar cam even though the specs don't look like it's worth it. Personally, I have no experience with any aftermarket cam in a 4.0 so I would wait for more opinions before making your final decision.
 
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Sounds like a good choice, you can alway go back after the fact and install the yella terra 1.7's if you want to eek a little more out of the cam.
 
The Mopar cams do improve power over the late model cams even though the duration is less 'cause as I stated earlier, the overlap is less and thus the dynamic compression is more. Compression ratio calculator from Jeepstrokers: http://www.jeepstrokers.com/calculator
The dynamic comp from the renix/obd1(87-95) installed -8* is 6.36:1, installed straight up 0* is 6.82:1. The dynamic comp from the 96-01 cam is 7.47:1. Install the Mopar 28 straight up and it is 7.73:1. Install the Mopar 29 straight up and it's 7.56:1. So with the 28 you have more low-end torque and have it earlier, and it lets more air in with lift at .43" compared to the 87-95's .424" and the 96-01's dual pattern .408in/.414"ex. The downfall with the 28 is that the power drops 500rpm shy of redline(no biggie).
 
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