1700/1800 Rod Bearings

[Vanapplebomb]

Does anybody know the specifications for the large end of the connecting rod, preferably in mm? I just took apart a motor and need new bearings. I need to know if the rods have been bored out larger at some time or another, and if they have, how much larger than stock so I can order the correct bearings. Also, how must eccentricity is allowable before they need to be bored for a larger bearing?

Thanks!
_________________
1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[raygreenwood]

This is virtually never done. Rods are "resized" meaning they pull the cap off and face a couple thousandths off of each part. They bolt it back together and then hone it back to spec on a rod machine.

Back to spec means that the crank should have already been machined if necessary. Then yiu buy a set of undersized bearings and they measure the crank pin and bearing shell thickness......add that together and hone the rods until the dial bore indicator says they are there.
Typically if it requires more than a light honing to get the rod big end back to round and in apec for the bearings.....the shop monkey will tell you whether its worth going further or getting a new rod.

Oddly the stock rod big end size is not in any of my better books. Its not in "without guesswork". I did a quick measure of one that needs to be rebuilt and was resized about 100k miles ago.
2.275" to 2.277".
Ray

[Vanapplebomb]

Thats odd that you couldn't find an exact specification either. And here I thought it was just me.

A couple weeks from now I will be dropping off the crank to get polished. It measured out almost brand new. Taper and eccentricity of the journals was virtually non-existant. Once the automotive machine shop gets that polished I will bring in the rods and have them take a look-see.
_________________
1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021