Gti6 Engine Rebuild

[leitoo 0]

After owning the car for two years now I've finally found a XU10J4RS for a conversion (just a handfull of these made it over to where I live). The problem now is the engine is in need of a rebuild. I've been sourcing parts but they are quite hard to find, and really expensive even for a std engine.

 

First problem is finding pistons, other than the OE items. I've been offered a set of Monopol that are supossed to fit straight on. Has anyone had any experiences with these? The factory is based in Spain which means some of them might have found their way to your market...

 

Other than that are there other OE pistons that fit the XU10J4RS? Maybe from XU10J2?

 

Any advice/experiences will be greatly appreciated!

[taylorspug 7]

Piston-wise there are a few options, Wossner and Wiseco are two names worth looking into, they do pistons for the GTI6 engine in various guises, all of which are im sure listed on their respective web sites.

[DrSarty 90 1 Cars]

And I'm not sure, but I wouldn't have thought XU10J2 pistons would be an option due to differences in valve pocketing and dish/dome sizes.

 

I suspect the custom forged ones designed for that engine like Monopol or the two companies Dan has suggested would be better for you.

 

Nice to hear from Argentina again. How's Nico?

 

NNN can get custom parts made like verniers (although the 10JRS has those anyway from factory) and a variety of head gasket thicknesses, so I'd suggest choosing the right cam, piston and compression ratio combination to make a really special engine.

 

Good luck.

[NNN 1]

I know sourcing RS pistons is quite difficult around here... what I think would be kind of easier is building the engine with 2.0 Mi16 pistons and 152mm rods (either from a xu10j4 or j2). It´s the same block heigth. Xu10j2 pistons are about the same compression height as the xu10j4 ones (0.9mm more by the way... maybe better regarding squish clearence) and you could easily machine the valve pockets... plus they are easy and cheap to source from FM or Mahle in Arg...

 

OFFT: I´m doing fine Rich thanks!!

 

ps: sos un chanta leito... jaja

[leitoo 0]

Thanks everyone for your responses.

As far as reliability goes are the Monopol ones ok? This is my main concern...

The idea is to go for a std setup at first and some mild cams a few months later, nothing much really so forged pistons won't be necessary

 

Off: Rich Nico is doing Ok, as he said... His car is still off the road... He says it might be running towards the end of next year, I believe cars won't be using fosil fuels anymore before he's finished! LOL

[taylorspug 7]

Tbh with standard pistons even the mildest of cams will leave you with VERY marginal valve to piston clearances. A few people on here have had problems with this. Id really suggest looking at some forged pistons if you are intent on buying new, or even getting the standard pistons pocketed to increase the valve cutout size.

[leitoo 0]

That's excellent information Taylorspug!

I will make sure to enlarge the pocket on the pistons before they go in

I'm trying to get a sample in the next few days to a company here that makes forged pistons (IASA) to get a quotation on the job. I will make sure to tell them about the bigger pocket.

How much deeper must they go?

[DrSarty 90 1 Cars]

How much deeper must they go?

 

How long is a piece of string?

 

What I mean is, you need to know exactly what YOUR engine needs, based on how much lift the cam gives at TDC in conjunction with how much your head has been skimmed, block has been decked and how thick/thin your head gasket is.

 

If everything's absolutely standard, then they should be able to just duplicate pocket sizes on standard J4 pistons providing everything else is equal.

 

What I've been advised on several builds to do is do a trial, dry assembly, with a pre-squashed head gasket and no piston rings to see what sort of valve to piston clearance you get. I suppose in theory, every bit of material you remove from the piston face, the lower your CR will get. But of course that's much better than having either the valves clash with the piston or even clip each other if your cam timing's off.

 

Hence the piece of string comment. A test build is the only real way to be sure.

[welshpug 1,661]

Dont know if you can see this, pretty sure you can without creating an user account, a lot of information on the clearances in the XU10J4RS engine.

 

http://www.306gti6.com/forum/showthread.ph...4146&page=1