Complete VR6 Rebuild Need Help

[Quiz 0]

Im doing a complete rebuild on a 92 VR6 OBD1. My main thing is that vw's always run hot. I have to bore the block because 1 of my cylinder walls is scorched fairly bad. I want to go up 2 sizes or .20 over. Has anyone bored a block and can you give me any feedback or anything you wish you had done different on your rebuild?

[Skimask 0]

You'd better ask the advice of the engineering shop that is doing the job. I'm not sure about the ABV engine, I don't think it has a liner and the most you can take out is .10 oversize - I'm not too sure on that though!

Best bet would be to take the block to the engineering shop, they'll be able to advise you better.

[Quiz 0]

Well that brings about another problem cause i am having a hell of a time finding a machine shop to mill the block. Most of them want the pistons before they do the work so i have to buy the pistons first. I dont want to order 800 dollars worth of pistons and then someone tell me i cant use them. Im just looking for someone who has done any serious building on a vr6 that can tell me what they have done. Im starting to think noone has bored one of these out. I dont like to be the guinee pig. I could use some advice. Thanks.

[Skimask 0]

Quiz,

I'm sure a few people on here have already rebored their engines. The engineering shops you've visited could be a lot more helpful with information. I think it's standard practice to buy the pistons and rings for the engine, unless you have an account with them. As always try the search on the forum, the info will be there it's just a case of finding it.

[Kevin Bacon 5]

Yes, good machine shops will need the pistons first.

 

A lot of aftermarket pistons are not identical believe it or not. There are always slight manufacturing discrepencies affecting size and shape, so you can't just bore 6 identical holes and hope for the best. Each piston is measured and it's cylinder bored accordingly.

 

I've had 83mm and 83.5mm blocks done no problem.

 

I prefer Wossner pistons, they only need 20 thou clearance compared with 45 thou for JEs, so they don't wobble up and down the bores half as much. The JE rings are a bit of a pain in the arse too. Wossners drop in perfectly and easily...... the guy who developed them has a VR turbo himself, so put a lot of development into them.