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Weird Pistons
MrSpeedy - June 18th, 2014 at 10:37 PM

I picked up these pistons off ebay a while back and they finally turned up in the mail. The ad was a bit vague but the price was right so I grabbed them. They were advertised as being forged to fit "big bore VW" but the crown looks wrong to me. There are no part numbers or brand markings on them either. They are 94mm bore and vw wristpin, just a weird dome on them. Anyone ever seen anything like them?

I might see about getting them milled flat so I can use them.


waltermitty - June 19th, 2014 at 09:37 AM

must be for something else there are only three of them.
Mitchell


bajachris88 - June 19th, 2014 at 10:02 AM

does the crown sit nicely in a 94mm type 1 head?


Camo - June 19th, 2014 at 12:49 PM

The problem I see is tha the crown is on the side and not at the top or bottom as required in our VW motors. I think you can have a slightly raised on the upper side (towards top of case) to raise compression, but unless these are for a big deck height and to compensate lower compression I think you need to look into it further.

Also, as I said I believe the raised section is in the wrong position for VW.

Kev


MrSpeedy - June 19th, 2014 at 01:16 PM

I haven't got a head spare at the moment to see how they fit unfortunatly. They might end up as shiny ash trays if they arent suitable for the 1916 I want to build :(


Performance Upholstery - June 19th, 2014 at 07:07 PM

Ask Dave butler... He'd be able to give you an explanation.


matberry - June 19th, 2014 at 08:53 PM

Not VW in my opinion


fish26 - June 19th, 2014 at 09:56 PM

Could be VW but not air-cooled


hulbyw - June 19th, 2014 at 10:34 PM

There was an article in Hot VW's a while back where they used modified Toyota pistons in a VW engine. If I can find the mag I will post more details
Cheers......Wayne


helbus - June 19th, 2014 at 10:50 PM

Check the deck height and the compression ratio that will be achieved based on the head cc. Were rings included?


modnrod - June 20th, 2014 at 12:24 PM

Mill the piston top flat, then it looks just right.


hulbyw - June 20th, 2014 at 05:53 PM

Found the HotVW's mag. The Toyota pistons actually have a negative dome piston, so completely different to the ones you have bought. They are cast not forged. Article mentions about wrist pin offset which is something you may need to consider
Cheers.Wayne


dangerous - July 16th, 2014 at 08:41 AM

Yes those are made for AC VW and others too.
Making a big cam fit is bogus, and the lump is right in the way.
Make sure the gudgeon pin is in the right way, it should be solid on one end.