Machine shop tells me that they have to go .040 over not .020 is that legit?????

[mtnbob]

My 1.6TD is at the machine shop and they are telling me that it still has original standard size pistons in it but that they are going to have to bore it out to .040. They tell me that because of the high wear on the cylinder walls it is too close to bore it out to .020. They tell me that it may be possible to hone it to .020 but that it could take 7-8 hours and will cost a ton due to the time and the fact that it will wear out the honing stones. They also tell me that it won't be as accurate that way. They came highly recommended and have done quite a few VW diesels, I just want to run it by the VW gurus on here and get your thoughts on this.

Thank you
Robert

[R.O.R-2.0]

that sounds like a big load of BS to me...

[macka]

so no cutting and straight into the hone? Did they say anything about being out of round or tapering?

[R.O.R-2.0]

so no cutting and straight into the hone? Did they say anything about being out of round or tapering?

usually a used bore will be out of round, and tapered.. a hone job will not true up the cylinder..

[mtnbob]

No, they did not want to hone it at all and discouraged me from that course, but they said that the only way to do it right was to bore to .040 oversize. I asked why they could not bore it out to .020 oversize and they told me that it was too close since it was pretty well worn, and that the only way to get it to .020 was to hone it and they didn't recommend it. Does that sound ok?

[Toby]

It sounds like they do not know what they are doing. Or they are just lazy. A reputable shop will bore the worst hole until it cleans up and measure that, in order to know what oversize is needed. They are only going to get within .003" or so of the finish bore size anyway with the boring bar and take the rest with a CK-10 Sunnen hone (or equivalent). That is IF they are properly equipped and know what they are doing. Run from any shop that is hand honing their bore jobs, BTW. And make absolutely sure that they understand and follow the directions that come with Kraut pistons. They are a thing unto themselves and are not clearanced nor measured like the rest of the word. All those number on top of the pistons mean things that need to be followed and the pistons are not measured in the same spot as everything else so it is typical to get the bore size to larger than spec w/o realizing it. I have had high miles MB motors that rattled more after the rebuild than before.

[macka]

so no cutting and straight into the hone? Did they say anything about being out of round or tapering?

usually a used bore will be out of round, and tapered.. a hone job will not true up the cylinder..

thats a given but I have heard of a couple shops that try to trick you by saying they will save you money etc etc by just doing a hone.

[Baron VonZeppelin]

I've heard of quite a few STD. bore VWD blocks that had to go .040 because .020 wouldn't be enough to make all clean and strait.
And .030 is not an offered piston option for us.

Thats all they are really trying to tell you.
The hone deal was them being overally honest.
It 'could' be done that way with hone stones on a boring bar.
But its not most desirable or most cost effective.

Most of the blocks that can be cleaned and straitened at .020 - are the same blocks that most of us would just normally hone and re-ring STD. ourselves in our own garage.

There has been mention lately of .040 rings being hard to come by for some reason. I didn't read up on all of it. But check into what can be bought - get them in the hands of the shop - then have the boring done. DanCorey was having trouble with .040 stuff in his 83 TD build thread. And someone else.

Another option is re-sleeving to STD. if your pistons are really nice.
But i'd save that for after you wear out the .040 overbore.

[theman53]

I would go to a different place that has done VW stuff before.

[maxfax]

How many miles/what kind of life did this engine have??  Did they happen to mention what the current measurements are??

Typically a .020 bore will clean em up, but if it's had a rough life (beaten, neglected, grandma'ed, etc) it isn't totally out of the question that it may take an .040 to clean it up...  The abortion I've been trying to get together took an .040 bore. with just 200K miles..  The machinist and I batted it back and fourth for some time trying to decide if an .020 was gonna clean it up or not..  Since it's best to have your pistons on hand before boring I just opted to go .040 and be done..  My thinking was that it's going to go at least another 200K (probably much more this time), and by that time TDI's will be dirty cheap... 

[mtnbob]

That is pretty much what I am thinking. The shop is the best around. And they weren't trying to get more money out of me they were just making what they thought was the best suggestion for the money. I didn't even know that you could re-sleeve the cylinder walls.

[macka]

That is pretty much what I am thinking. The shop is the best around. And they weren't trying to get more money out of me they were just making what they thought was the best suggestion for the money. I didn't even know that you could re-sleeve the cylinder walls.

IIRC they spray weld the sleeves and rebore and hone them.

[mtnbob]

What does IIRC mean

[nathan_b]

google my friend

[macka]

IIRC = If I remember/recall correctly