[Louie L]

Guys i need help with cam bearings. Im in the middle of my low budget rebuild on the T Type. Im currently stuck at the cam bearings.

I have a set of Durabonds here, full set tricked out and redilled for oiling per the Buick bible. All the bearings are the same size part number BP 13-1.

I have also a stock set of SH-1448s Clevite 77s. These are the same OD as the Durabonds.Flatlander lists this part number for a full set.

But inside the box it states that bearing 1-4 (1448s)are the same 2-3 (1449)are smaller. I measure the stock GMs and this is correct.

Durabond only offers this number for Buick V6. Several posts i have found state that they are all the same , some say they are not.....I am confused.

Per clevite 77 :

1-4 are 1.935
2-3 are 1.915


Will all 4 of the same size work ?

<small>[ August 09, 2003, 07:30 PM: Message edited by: Louie L ]</small>

 

[Louie L]

<small>[ August 09, 2003, 07:27 PM: Message edited by: Louie L ]</small>

 

[Louie L]

Now come on!!!

Jesse i know u know some thing about this! Kendall?

 

[Orlando_87GN]

Sometimes good answers take time It's not like you asked a question about what's the biggest tire I can fit on my GN? I am sure we'll get it answered!

 

[salvageV6]

<small>[ August 10, 2003, 10:58 AM: Message edited by: salvageV6 ]</small>

 

[CallMeMud]

4.1's take a different set than the 3.8 with two different sizes. I only say this because when I bought my 3.8 Teflon coated bearings in my current motor I was told by the machinest that the 4.1 was like this and had to order a special set for it. I only use the Teflon coated Durabonds now in my 3.8's. I will look here in a second at the box of spare ones I have and see what the number is. They run about $35.00-$45.00 a set.

 

[Steve Wood]

Altho mentioned before, I have never seen a definitive answer.

The shop manual lists all the cam bearing journal diameters as being the same.

But, it shows the journal clearance in number 1 as being .0005-.0025" while #2,3,4 are listed as .0005-.0035". Minimums are the same but the last three can be .001 looser. It would make sense to me that one wants to keep #1 tighter to maintain oil pressure.

From the clearances, it would seem that one size should fit all in most cases but some may offer a set with a tighter number one or a tighter 1,4.

I guess the solution is to measure and make sure number one is within spec.

I am curious about the teflon bearings as I have always heard that teflon offers low friction but does not hold up to pressure when used as a coating.

 

[CallMeMud]

3.8's O.D.'s and I.D.'s are all the same. 4.1's O.D.'s are different but the I.D.'s are the same and that is the reason cams are interchangeable.

 

[CallMeMud]

Okay,

My 4.1 is a 1984 year block. That is the last year that took two different size bearings. The 1985 and up blocks use all the same size.

 

[CallMeMud]

BP-13T


That is the Teflon coated Durabonds.

 

[Louie L]

and are those for a 3.8 block or 4.1. Mine are the same with out the 't'

 

[CallMeMud]

BP-13T is what I have in my 3.8. I found a listing for Durabonds on one of the sites before (maybe www.flatlandersracing.com) and it showed BP-13 and BP-13T (Teflon) both on the 3.8. I think you are a go.

 

[CallMeMud]

I did I did: http://www.flatlanderracing.com/duracamgm.html

 

[CallMeMud]

Clevites too: http://www.flatlanderracing.com/clevcambearings_buick.html yup headbang

 

[Louie L]

Jes, Thanks for the links. I had been to those before. Both list a single part number bearing, one size set. Lee Thompson replied on the other board that they are indeed different.1&4 and 2&3.

Im confused again.

silly

Thanks for the info wink

 

[CallMeMud]

I looked at my 13's and they are all the same size. I looked at my 4.1 bearings before they went and and they were noticeably different sizes.

 

[Louie L]

The main issue i have is that the stockers(pos 2-3) were smaller. So im still wondering the if the diff between the 2 measurememts is enough to keep the bigger ones from being installed in the 2-3 position. This sounds like what many may be doing, using the large bearing in all 4 places.

 

[Steve Wood]

Don't the factory specs that I posted above correspond?

 

[JB.Racing]

Hi Louie.
If you are rebuilding a 3.8L Turbo Block. Don't worry about the Cam Bearings being different. THEY ARE NOT. I have rebuilt Tons of Buick Motors, and I use either Federal or Clevite Bearings and drill different Holes in them to give more oil to the Crank. Any will go at any place.

I hope that this will Un-confuse you...

Joe

 

[TurboDave]

JB.Racing:
Hi Louie.
If you are rebuilding a 3.8L Turbo Block. Don't worry about the Cam Bearings being different. THEY ARE NOT. I have rebuilt Tons of Buick Motors, and I use either Federal or Clevite Bearings and drill different Holes in them to give more oil to the Crank. Any will go at any place.

I hope that this will Un-confuse you...

Joe

Must be a bear cramming the front and rear bearings in then. I just went out and measured the journals on the 3.8 that came out of my 86 (original engine). and the front and rear journals measure 1.935, and the two inner journals measure 1.9155. That's about a .020 difference. I also measured the cam bearings that came out and sure enough they are different sizes that coincide with the above measurements.

Now, the bearing journals on these stage 2 blocks I have laying around are all the same size, 1.915-1.916



<small>[ August 12, 2003, 10:04 AM: Message edited by: TurboDave ]</small>