4.1 cam bearings are different than 3.8?

[Intercooler]

I never built a 4.1 until this one but I was told today we can't use the same Teflon coated cam bearings I put in the 3.8 because the dimensions are different. I think it was #1 and #4. True/false?

 

[6PacktoGo]

Originally posted by Intercooler
I never built a 4.1 until this one but I was told today we can't use the same Teflon coated cam bearings I put in the 3.8 because the dimensions are different. I think it was #1 and #4. True/false?

According to my Clevite catalog, they take the same bearing set as a 14 bolt 3.8. If you need them, I'll look up individual part numbers and locations.

 

[Lee Thompson]

cam bearings

75-85 -- 14 bolt pan--- the block bore is the same dia. for all 4 bearing. The #1 bearing is wider. I assume for the heavier load.
85-88---20 bolt pan--#1-4 bore is .020 larger. They also take the wider bearing.
A 14 bolt pan set will have --1 wide bearing--3 narrow bearings
A 20 bolt set will have 2 wide bearings which is .020 larger than the 2 narrow bearings.
Clear as mud!

 

[Intercooler]

Re: cam bearings

Originally posted by Lee Thompson
75-85 -- 14 bolt pan--- the block bore is the same dia. for all 4 bearing. The #1 bearing is wider. I assume for the heavier load.
85-88---20 bolt pan--#1-4 bore is .020 larger. They also take the wider bearing.
A 14 bolt pan set will have --1 wide bearing--3 narrow bearings
A 20 bolt set will have 2 wide bearings which is .020 larger than the 2 narrow bearings.
Clear as mud!

The way it was explained to me, they will not work

 

[Lee Thompson]

Bearings

I guess it is not clear as mud. I am so confused. What won/t work? Does this mean I need to pull my eng. as I have cam bearing that are wrong?

 

[Intercooler]

Well from what my machine shop guy told me:


All 3.8 and 4.1 cam bearings are the same I.D. and that is the reason the cams are interchangeable.

The O.D. of the #1 and #4 cam bearings in the 4.1 are bigger and wider than the 3.8 bearings so a complete set of 3.8 bearings can't be used in the 4.1 block. I can use the centers but #1 and #4 has to be 14 bolt specs.

 

[KendallF]

That's exactly what Lee told you above... Lee, I think your motor's safe. Big sigh of relief!

 

[9SECVSIX]

Cam Bearings

Intercooler. Tell ya we did to a Stg11- 4.1 block last winter, you are using a 4.1, right?
Bore the cam bearing bores out in the block to the size of the front and rear bearing bore in the 3.8 block (this is .020" more) Buy 2 set of 3.8 bearings and use the 2 wide ones from each set. now you have 4 wide cam bearings in the block.
Later
9 Sec.

 

[Lee Thompson]

cam bearings

Intercooler, you are saying your machinest told you that the 4.1 has larger od. bearing in #1-4 bore. I/m saying the later 3.8 ( 20 bolt ) is the one that takes the larger bearing. Maybe you misquoted him or he said it backwards. From my limited experience with the eng. what I posted I believe is correct.
As a side note, if anyone should ever spin one of the 2 center cam bearings ( as I did, not once, but twice) they can do as 9SECVSIX said line bore to the bigger bearing.

I rest my case!!

 

[Intercooler]

Re: cam bearings

Originally posted by Lee Thompson
Intercooler, you are saying your machinest told you that the 4.1 has larger od. bearing in #1-4 bore. I/m saying the later 3.8 ( 20 bolt ) is the one that takes the larger bearing. Maybe you misquoted him or he said it backwards. From my limited experience with the eng. what I posted I believe is correct.
As a side note, if anyone should ever spin one of the 2 center cam bearings ( as I did, not once, but twice) they can do as 9SECVSIX said line bore to the bigger bearing.

I rest my case!!

Yes, same thing