bearing help 2.8v6

[truckdude239]

Building a 2.8 v6 for a friends s-10 blazer after it blew the intake gasket and filled the oill with water looking at replaceing the rod and main bearings as there is wear on them, main bearings are .75 oversize no problem, the rod bears are hard to tell because the only numbers on them are bb-153 which cross to a cr-641Si with a min diamater of 2.0990 max diameter of 2.1000 . the stock diameter is 1.9983-1.9993 so how do i tell what size bearings i need to order i know its not stock size

btw its an 86 s-10blazer with 2.8 v-6 thats been worked before

http://www.northernautoparts.com/Pro...ntoryId=124081

[cableguy0]

If theres wear on the bearings the crank is worn. You need to get that crank to the machine shop and have it measured and most likely reground. Throwing new bearings on a worn crank is going to be a bandaid that likely wont last. If it was run after the water oil mix all the bearings are hurt. Cam,Main and rods. Your likely going to end up with either low oil pressure or a knock from too much clearance if you dont do a complete rebuild.

[truckdude239]

Motor had 20k miles on it down beari gs didnt look bad just a precation guess ill take it and have it measured
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[cableguy0]

The thing is antifreeze is caustic to engine bearings. It makes them fall apart. As the pieces come off of the bearings they hurt the crank. Were talking thousandths of an inch. You cant see it with your eyes. The 2.8 isnt a very robust engine in the first place. Its going to need to be right or its going to be coming right back apart. Just trying to save you some grief.

[truckdude239]

well after checking the crank very colsely we found some deep grove in one pournal, so off for a reman crank

[truckdude239]

well picked up my new reman crank with matching bearings, just to find out the clearances on the mains still aren't right the rods are perfect but the mains at at .02 and its suppose to be .0016 which mean the mains have been line bored and i guess the block is taking a trip to the machine shop with the new cranks so he can tell me what i need

[GASoline71]

I had fits with the bottom end of a 2.8L in an '82 Camaro back in the day. Ended up just swappin' in another used lo-mile 2.8L engine.

Gary

[cableguy0]

The 2.8 wasnt the best engine from the beginning. Gm doesnt even sell reman 2.8's anymore. They will sell you a 3.1 to take its place. If I were your buddy I would just swap over to the 3.1 and call it good.

[GASoline71]

After I did the engine change. I really wish I would have went over to the 3.1L. After the new "used" engine went in. It lasted about another 25,000 miles and did the exact same thing. Don't know what the heck GM was thinking when they designed that 2.8L 60degree V6.

Gary

[clinebarger]

4.3L swap?

[cableguy0]

4.3 would be a good choice only problem is the bell housing is different. The 2.8 was a 60 degree v6 and uses its own bellhousing.

[raceman6135]

Originally Posted by truckdude239

well picked up my new reman crank with matching bearings, just to find out the clearances on the mains still aren't right the rods are perfect but the mains at at .02 and its suppose to be .0016 which mean the mains have been line bored and i guess the block is taking a trip to the machine shop with the new cranks so he can tell me what i need

FYI: line boring a block has no effect on what undersize bearings are required. The hole in the block where the bearings are installed should always be the same size, and if the crankshaft is turned undersize, the bearings are thicker to compensate.

[truckdude239]

Line boring the block thatz material ofc the block to ture the holes so it changes the hole size from factory
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[raceman6135]

Originally Posted by truckdude239

Line boring the block thatz material ofc the block to ture the holes so it changes the hole size from factory
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If the block is in that bad of shape that the main bore is now 0.020" (twenty-thousandths of an inch) larger, I'd seriously reconsider using it.

In the performance world, the caps are cut approximately 0.003" and then the line bore or line hone is performed to bring the bore back to factory specifications. At 0.020", the machinist removed about 7 times more material than was probably necessary.

Sounds like that engine was very abused before your friend bought it. S/he may want to really take an honest look at how much money is being swallowed up into this project before s/he proceeds.

That's just the advice of a guy who's made his fair share of mistakes and has the pile of broken parts to prove it.

[truckdude239]

Engine was a reman about 4done years ago it has about 15k on it cylinxers look great. Just blew the intake gasket anx vot run with water in the oil
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[truckdude239]

droped by the machine shop block is fine i was reading the platic gage wrong but they are knocking new cam bearings into it

[bwood]

Here's a thought if the 2.8 gets to be a pain:
http://sdparts.com/details/gm-perfor...parts/12363230

Edit: Nevermind, its for carb'ed engines only 82-85

[GRX]

Originally Posted by truckdude239

droped by the machine shop block is fine i was reading the platic gage wrong but they are knocking new cam bearings into it

Been following this thread. Figured that is what happened. Good idea on the new cam bearings. They probably already suggested it ... you should also have them remove all the oil galley plugs and hot tank the block to ensure no bearing material remains within.