Went to the local pull a part today

[dwg86]

They have a bunch of Cherokees. Some late 80's with 258's, a bunch of mid 90's with 7120 heads, and about a have dozen 96 and 97 models. Crank shafts $30.00, heads $30.00, 6 cylinder engines $120.00. Go to www.pullapart.com to check to see if there is one close to you. Parts are cheap,yards are clean and neat. Prices are on their web site.
There was a 1975 cherokee with a 258 that was out of the truck. Crank and rods where gone. Maybe someone might be building a stroker? Anyhow, I was able to get a look at the camshaft. It had narrow lobes. I know there was questions about the 258's having narrow or wide lobes. That engine had a narrow lobe camshaft. I don't know how many miles it had on it, but it was showing some signs of wear. Also the lobes had casting flaws(small pits or holes) in them... Just some gee wizz info.

[Muad'Dib]

Yeah u-pull-it's are awesome.

[John]

Not trying to be argumentative but did you check the casting number on the camshaft or the casting number on the block, the year you are talking about came with both the 232 and 258 engines as factory options. Just haven't seen a narrow camshaft in a 258 that was stock.
John

[dwg86]

No I didn't. I just assumed it was a 258 because the crank was gone...can use a 232 crank to build a stroker(still assuming it the crank and rods were gone to build a stroker). Also it was full size cherokee. They never put a 232 in in a full size cherokee, But yes I know it could have been changed in the past 30 years.

[John]

Thanks, I am not the expert on this issue, just have seen about a dozen 258 OEM camshafts and all were wide lobe, I would really like a definitive answer to this puzzle. Again thanks....
John

[dwg86]

I would also like to find out an answer. I have talked to every aftermarket cam company and I always get the same answer "It doesn't matter how wide the lobe is...the lifter has a crown on the bottom and the lobe is tappered,so the surface contact is small". Now I do agree with that statement, but my question is still "why are the aftermarket lobes narrower that the stock lobes. No one can answer that question, and don't really care to find out why! And also, why do the stock cams last so much longer that the aftermarket cams...(too much spring pressure with the aftermarket cams maybe?) My Jeep is a 2003 wrangler. I used conventional oil for the first 18,000 miles (the same low zinc oil as everybody else). I switched to Mobile 1 after that, My Jeep now has 91,000 miles and still running great(no camsaver lifters or special EOS additive). So I don't think it has to do TOTALLY with low zinc in the oil, although that may be part of it.
I can't find the guys name and number I talked to from the camshaft manufacturer (the one that said they were going to cast the wide lobe cams).I thought it was CWC, but my mistake it wasn't. I'll find out though it may take some time, and a lot more phone calls.
One other thing I have been thinking about...If the lobe was wider and contacted the lifter further out from the center of the lifter, wouldn't the lifter turn easier? Kind of like trying to turn a cars steering wheel with no power steering. The bigger the wheel the easier it is to turn.

[Flash]

I would also like to find out an answer. I have talked to every aftermarket cam company and I always get the same answer "It doesn't matter how wide the lobe is...the lifter has a crown on the bottom and the lobe is tappered,so the surface contact is small". Now I do agree with that statement, but my question is still "why are the aftermarket lobes narrower that the stock lobes. No one can answer that question, and don't really care to find out why! And also, why do the stock cams last so much longer that the aftermarket cams...(too much spring pressure with the aftermarket cams maybe?) My Jeep is a 2003 wrangler. I used conventional oil for the first 18,000 miles (the same low zinc oil as everybody else). I switched to Mobile 1 after that, My Jeep now has 91,000 miles and still running great(no camsaver lifters or special EOS additive). So I don't think it has to do TOTALLY with low zinc in the oil, although that may be part of it.
I can't find the guys name and number I talked to from the camshaft manufacturer (the one that said they were going to cast the wide lobe cams).I thought it was CWC, but my mistake it wasn't. I'll find out though it may take some time, and a lot more phone calls.
One other thing I have been thinking about...If the lobe was wider and contacted the lifter further out from the center of the lifter, wouldn't the lifter turn easier? Kind of like trying to turn a cars steering wheel with no power steering. The bigger the wheel the easier it is to turn.

That last statement is right on the money!!!!! I hadn't thought about it that way, but thats true.

With the lobe contacting the lifter closer to the center, the lifter spins faster.(Wears faster do to speed and amount of surface it is using, but has less torque to keep it turning should there be.........varnish build up or something that put more drag in it like...........spring pressure!)
The factory wider lobe would turn the lifter at a slower rate, farther out on the lifter. Less speed or rpm of the lifter, but more torque, if you will, to keep it spinning.

One more thought on the wide issue. the crown of the lifter and the tapper of the lobe, Hmmm does the lifter and the lobe not completely contact each other at max lift? all the lobe wear patterns do to me! the the wider the lobe is at max lift the less P.S.I(Pound per Square Inch) would be applied on the lobe when the spring is pushing at it hardest.

Now mater how you look at it, Wider is better!


Flash

[John]

"Now mater how you look at it, Wider is better!"

Ok, we'll agree with that statement if we limit the topic to camshafts.
John

[Flash]

"Now mater how you look at it, Wider is better!"

Ok, we'll agree with that statement if we limit the topic to camshafts.
John

No rebuttal on the rest of my theory

Flash.

[Flash]

I love this board--------------------------------------------------------------------------------->


Flash

[John]

Flash I think you are correct on tip loading, but compare the width of track of the lifter on the lobe surface on a used OEM cam and a narrow lobe cam, you might be as surprised as I was. Lifter of the centerline of the lifter hasn't changed and they really didn't cut the materials that much underneath the lifter.
John

[dwg86]

Flash I think you are correct on tip loading, but compare the width of track of the lifter on the lobe surface on a used OEM cam and a narrow lobe cam, you might be as surprised as I was. Lifter of the centerline of the lifter hasn't changed and they really didn't cut the materials that much underneath the lifter.
John

I keep reading this and I still don't get it. In the words of Forest Gump "I am not a smart man". Do you have pics?

[John]

"Lifter of the centerline" Should read "centerline of the lifter bore" (just another brain fart)
Don't have a used after market cam to give pictures of, but I think I can get some from the OEM's to show what I am talking about.
John

[Flash]

"Lifter of the centerline" Should read "centerline of the lifter bore" (just another brain fart)
Don't have a used after market cam to give pictures of, but I think I can get some from the OEM's to show what I am talking about.
John

So what your saying it that the "timing chain" side of the the cam lobe is at the same spot as the factory on?
The aftermarket narrowed the back side of the lobe that See's only wear on top of the lobe?

Have you got a pic of a stock lifter and a aftermarket cam/lifter were they rub or spin on the cam ????????


Flash

[John]

Remember Frank's cam failure pics, viewtopic.php?f=15&t=156
John