Main bearing question
#1
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based on an old 928intl catalogue, it seems that the main bearing sets for the older 2 valve models, is based on engine serial numbers
There is a single piece front main bearing or the older 2 halves for that front bearing. The challenge is figuring out which one to order.
my (Scot's) engine is an M28-11 and has a serial number of 8200778
The little 928 book shows 82C XXXX. Anyway, im almost positive i need the 2 piece bearing set, but how do you know for sure?
thanks
Mk
There is a single piece front main bearing or the older 2 halves for that front bearing. The challenge is figuring out which one to order.
my (Scot's) engine is an M28-11 and has a serial number of 8200778
The little 928 book shows 82C XXXX. Anyway, im almost positive i need the 2 piece bearing set, but how do you know for sure?
thanks
Mk
#2
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On upper half of the block there is small stud which holds single piece bearing from rotating. On two piece bearing block #1 bearing area should be similar to all other 4 mains.
#5
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Thanks guys. thats what i suspected. is there any difference in the thrust bearings?
what is that front bearing picture? hard to see what im looking at.
by the way, my 84ish crank, as i assume it's an 84 as it has the bigger oiling holes but the weight was off by as much as the new 5 liter pistons were heavier, rubs on the block. (i posted this information awhile ago) ive ground down the crank to not hit the side of the thrust bearing area of the block. seems odd that all the cranks woudnt be the same, but they are not.
so, warning..... Old block, new crank.
Mk
what is that front bearing picture? hard to see what im looking at.
by the way, my 84ish crank, as i assume it's an 84 as it has the bigger oiling holes but the weight was off by as much as the new 5 liter pistons were heavier, rubs on the block. (i posted this information awhile ago) ive ground down the crank to not hit the side of the thrust bearing area of the block. seems odd that all the cranks woudnt be the same, but they are not.
so, warning..... Old block, new crank.
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Mk
Originally Posted by Vilhuer
Also shows feed hole for piston squirter. ![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
#6
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Originally Posted by mark kibort
what is that front bearing picture? hard to see what im looking at.
Mk
Mk
#7
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Uhhh, sir, you are missing your cylinders ![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
Great shot! thanks. absolutely, I (scot) have an early block. no dowels. only the tell tail cut outs at the corners of the bearing area for the separate front main bearings, like you see on the other mains toward the rear.
turns out, just found out that the bearings changed in year '82, and anything older is separate mains in front bearing area.
thanks,
Mk
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
Great shot! thanks. absolutely, I (scot) have an early block. no dowels. only the tell tail cut outs at the corners of the bearing area for the separate front main bearings, like you see on the other mains toward the rear.
turns out, just found out that the bearings changed in year '82, and anything older is separate mains in front bearing area.
thanks,
Mk
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#8
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Height of the thrust bearing sides were increased in '82-83 time period IIRR. This meant that crank also got taller side areas which are machined to be counterparts for thrust bearing. Not sure without checking if this was done at same time as oiling hole diameters were increased in crank. It should be possible to use old style crank with new style block without mods. New style crank in old block can mean small changes to block in areas surrounding thrust bearing.
#9
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Here is what happens with old bock and new crank like you noted below in your message.
Originally Posted by Vilhuer
Height of the thrust bearing sides were increased in '82-83 time period IIRR. This meant that crank also got taller side areas which are machined to be counterparts for thrust bearing. Not sure without checking if this was done at same time as oiling hole diameters were increased in crank. It should be possible to use old style crank with new style block without mods. New style crank in old block can mean small changes to block in areas surrounding thrust bearing.