Replace Camshaft?
#1
Replace Camshaft?
I am rebuilding the 4.0 ohv from a 97' Ranger and I am getting different opinions on weather I should replace the camshaft or not.
Any thoughts?
The book indicates, when subtracting the minor from the major, the lobe should be no less than 0.005-inch less than 0.272-inch on any lobe. Now, 0.272 - 0.005 = 0.267. So 0.267 is the lowest the wear on the lobes could pass before the cam would need to be replaced, correct?
From front of cam to back, my readings are as follows:
1. 0.278
2. 0.279
3. 0.275
4. 0.272
5. 0.274
6. 0.280
7. 0.279
8. 0.274
9. 0.276
10. 0.266
11. 0.268
12. 0.274
The journals are fine per the books specs.
As you can see #10 and #11 are on the verge of the books specs.
The machine shop where my heads are being redone say that the cam and crank are good to reuse. Now mind you, he didn't meter the cam or crank, he said he could tell just by looking at it. He builds high end racing motors so I want to believe him, mainly because I don't have the extra funds to buy a cam, but, I don't want to pull the motor again 6 months down the road either.
Any thoughts?
The book indicates, when subtracting the minor from the major, the lobe should be no less than 0.005-inch less than 0.272-inch on any lobe. Now, 0.272 - 0.005 = 0.267. So 0.267 is the lowest the wear on the lobes could pass before the cam would need to be replaced, correct?
From front of cam to back, my readings are as follows:
1. 0.278
2. 0.279
3. 0.275
4. 0.272
5. 0.274
6. 0.280
7. 0.279
8. 0.274
9. 0.276
10. 0.266
11. 0.268
12. 0.274
The journals are fine per the books specs.
As you can see #10 and #11 are on the verge of the books specs.
The machine shop where my heads are being redone say that the cam and crank are good to reuse. Now mind you, he didn't meter the cam or crank, he said he could tell just by looking at it. He builds high end racing motors so I want to believe him, mainly because I don't have the extra funds to buy a cam, but, I don't want to pull the motor again 6 months down the road either.
#3
#4
I'm not the one to tell what is good or bad based on specs, RonD is the Man for that but since you have the engine apart, and you are REBUILDING it, why not get a cam that has a little more lift than OEM Specs.
Maybe a better duration for a little more power, that never hurt the 4.0 and 3.0 engines. You can ask your selected Cam Manufacturer what work, they help a lot when asked.
If you get a new cam get a new set of lifters, consider new rocker arms too.
Get the Cam bearings replaced by a machine shop and some machine shops sell performance parts for less than a Performance Speed Shop will.
My ideas cost money, that's a down fall in today's situation but in the long run you will be happier with your money spent on the rebuild.
Just me and my opinion, or is that IMHO... !
Ltr / Good Luck with the rebuild anyway way you go.
Maybe a better duration for a little more power, that never hurt the 4.0 and 3.0 engines. You can ask your selected Cam Manufacturer what work, they help a lot when asked.
If you get a new cam get a new set of lifters, consider new rocker arms too.
Get the Cam bearings replaced by a machine shop and some machine shops sell performance parts for less than a Performance Speed Shop will.
My ideas cost money, that's a down fall in today's situation but in the long run you will be happier with your money spent on the rebuild.
Just me and my opinion, or is that IMHO... !
Ltr / Good Luck with the rebuild anyway way you go.
#5
Well one weak point in the 4.0l was the lifters, the springs inside break so you get a "tick, tick, tick" noise, engine still runs fine
I have a 1994 4.0l and still have factory lifters, so not one for replacing anything that "still works", lol
Yes, I would replace the 2 lifters that have worn down the cam lobes, just on spec
As for the others, I wouldn't replace them but I also don't mind a "tick" or two, if I know whats causing it
But Scrambler is correct if you are rebuilding an engine then replacing the cam and lifters is almost a given
I have a 1994 4.0l and still have factory lifters, so not one for replacing anything that "still works", lol
Yes, I would replace the 2 lifters that have worn down the cam lobes, just on spec
As for the others, I wouldn't replace them but I also don't mind a "tick" or two, if I know whats causing it
But Scrambler is correct if you are rebuilding an engine then replacing the cam and lifters is almost a given
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Scrambler82 (04-22-2020)
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