Disassembling veggie block w/ piston slap- rod length?

[RustyCaddy]

i will talk with the machinist again.  He has done a ton of work on VW diesel engines but hasn't ventured much into modifications outside of stock.  He can get prickly about being questioned which i understand.  His timeline would probably be 8 weeks if he agreed and after that i could get some numbers on the piston protrusion.  So will pm you when i learn more and do some back of the napkin math of what this might run.  Right now it might be pushing $600 (with a custom head gasket included) so have to think it over some more.

[oblique]

Did you try getting pistons from Spareto?  I got a couple sets a few months ago for fairly cheap.  I just checked and they have them readily available.

Mr. RustyCaddy alerted me to a lcoal ebay auction for +1 KS pistons...I ended up buying all four sets...bought a lottery ticket too.

Speaking to Maggie at PP, they have used their Taiwan (Arco?) pistons in 200+ builds for over a decade and have had no issues...even with the rings, apparently. I'm quite certain that Hans sells the very same ones...so that's an option...especially for AAZ kits which are stupid pricey.

[fatmobile]

You mean you bought four pistons right?
 Not sets of pistons, right?
How much over, they weren't standard size right?

What kind of deal did you get?
 How $much$ for 4 KS pistons with rings?

[oblique]

No I bought 4 sets of +1mm KS pistons in sealed boxes....16 pistons total

I bought 2 sets initially then just ended up buying everything...i spent $1kCDN

Thank you RustyCaddy!! I owe you sir, literally lmk what I can do for you.

[fatmobile]

That's a super deal.
For something that's getting hard to find over on this side of the pond.

[RustyCaddy]

Oblique-Glad that you are preserving so many IDI motors and that the piston sets help

[oblique]

It's been pretty interesting learning about the details of these motors. I am about to reassemble the first block I had machined.

Couple of questions regarding piston protrusion.

My understanding is that the name brand oversize pistons are shorter - that the pin sits higher relative to the top/crown to account for planing the deck.

I did not measure piston height on either of the blocks I'm working on before disassembly. Both were stock bores and pistons.

I did take one of the old pistons so they can compare measurements but without pre-teardown measurements how much do I tell them to take off the deck? 0.1mm?


The other question was regarding rod bushings...do these typically wear? When I press in the new pins should there be any play? Is there are allowance at all? This veg block had pretty significant piston-valve contact. I'm assuming replacement bushings, if replaceable, are not easy to find.

[fatmobile]

I think the bushings are pretty easy to find.
 But I haven't looked lately.
 I do have them replaced when putting new pistons in.
 They also need to be reamed to fit the pins.
 Some folks have put the engine together and had a tick that doesn't go away when the ignition is turned off,
when they didn't change the bushings.

As far as the pistons protruding above the block surface.
 I usually install the pistons and check to see how high they are.
Sometimes swap to different holes.
 Sometimes one piston will sit higher than others.
 Sometimes the block needs ground at a slight angle,.. only talking thousandths.
 Shortest piston at one end and work up to the tallest at the other.

 It's not a given that the new pistons will be shorter, or that the block will need ground.
 
I just have to install them and see,.. kinda like finding out what valve clearance shims are needed.
Or if a valve might need a little ground off the top to make room for a big enough shim.
I don't put the valve seals in until I've put it together and seen that a valve isn't going to need removed to grind the top