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For Sale/Looking For => Parts for Sale/Wanted => Topic started by: NintendoKD on February 15, 2010, 03:26:30 pm
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You heard it right, I need 030 oversize pistons, having a helluva time finding this oversie size. If I wanted to bore to 5 over I would, but I much rather go with the size that I have. The pistons are in rough shape and I don't want to use damaged pistons for my build. Any info would be greatly appreciated.
Thanks,
Kevin
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This is from an early 1.6 block from an 83' rabbit turbo diesel "RARE" in case anyone was wondering. Got it from a guy in pollock pines in norcal. Interesting oversize, if I absolutely must go 5 over I will but I am sure these things are out there. just don't want to pay more that I would if I were to go oversize 5 over machining cost plus the new pistons. In otherwords I need em' cheap, or I don't need em. Don't mean to sound the scrooge or anything.
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1.6 pistons are generally sold in .5 and 1.0 mm oversizes, that is .020 and .040
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sooooo no in between? mine literally say 030 on top of the piston is that normal?
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they should have the piston diameter stamped on there, like this:
(http://i229.photobucket.com/albums/ee139/truckinwagen/PA230004.jpg)
see the "76.72" stamped in the piston?
these are third oversize(I think) there is a chart in the bentley that lists the oversizes and the piston diameters that go with them.
if nothing else you can take a pair of calipers to your pistons and consult the chart in the bentley to figure out which oversize they are.
-Owen
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Those pistons in the picture are probably the "1st" oversize. It went 76.50-std, 76.75-1st, 77.00-2nd, and 77.50-3rd. This is in general. I don't think anybody but VW themselves actually sold true "1st oversize" pistons. At least, I've never seen an OEM sell them.
As another interesting side note, there are actually different sized pistons within a given "oversize". The piston in the picture is a perfect example of this. The second oversize can actually be 76.98 or 77.00mm. I think it has to do with the manufacturing tolerances. They group similarly sized pistons with each other, right down to the 1/100mm. VW even catagorizes them as "blue" or "pink", etc. to indicate which actual size they are of each given oversize.
NintendoKD, I would be a bit surprised if that really is a .030 oversize piston you have there since it doesn't really "fit" the idea of .020 corresponding to 77.00mm and .040 corresponding 77.50mm pistons. If they really were .030 oversize pistons, they would probably have to be 77.25mm which is a size I've never heard of. I think the best advice would be measure it and go from there.
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Well do, have to wait til wed to see though, stuffs locked up at the shop. Been wrong before, so this wouldn't be a first ;D
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http://cgi.ebay.com/ebaymotors/VW-VOLKSWAGEN-NON-TURBO-DIESEL-KS-PISTON-SET-1st-OVER_W0QQcmdZViewItemQQhashZitem3c96ae526cQQitemZ260226044524QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories (http://cgi.ebay.com/ebaymotors/VW-VOLKSWAGEN-NON-TURBO-DIESEL-KS-PISTON-SET-1st-OVER_W0QQcmdZViewItemQQhashZitem3c96ae526cQQitemZ260226044524QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories)
Here? I purchased a set of 2nd overs from this guy and the sale went just fine. Honest seller.
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You heard it right, I need 030 oversize pistons, having a helluva time finding this oversie size. If I wanted to bore to 5 over I would, but I much rather go with the size that I have. The pistons are in rough shape and I don't want to use damaged pistons for my build. Any info would be greatly appreciated.
Thanks,
Kevin
never seen a set of .030 over pistons ofr a VW before. the size of the piston is usually the diameter, not just the over size amount. it should say 76.48, or 76.98 or something along those lines, on the top of the piston.
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The .030 stamping is expressing the amount of cylinder wall clearance you need: .030 mm
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So I may have stock pistons yet :D *crosses fingers* I'll be sure to check tomorrow.
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By the way, I have a set of 5 brand new Kolbenschmidt turbo diesel pistons for sale. They're "2nd" oversize at 77.00mm (.020). I know you only need 4 so I'll give you a good deal on just four, or throw in the 5th for not a lot more. LMK
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*sighs* if I have oversize I'll keep you in mind, I need new ones regardless and am really trying to keep from having to machine. Regardless I'll keep you posted. 8)
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*sighs* if I have oversize I'll keep you in mind, I need new ones regardless and am really trying to keep from having to machine. Regardless I'll keep you posted. 8)
so you are spending all this time and money on this engine, but you cant drop a hundred bucks to get the block bored out to the proper size? it really doesnt make much sense to me. knife edge the crank, dry sump oiling, 1.9 head, but its still got the same bore VW manufactured it with who knows how many miles ago? that does not make good sense to me. and your pistons are already messed up, so you need different ones anyway? so why not just get it bored and call it good?
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If it aint broke don't fix it. The bores still had cross hatching when I got the block, to me that means that the bores are still good, but that's just me. I am trying to avoid all of the machining that I can, i'ts a pain to keep taking it back to the machinist and hear his I-told-you-so speech again and again :P ::) No, but seriously, the bores are fine, why mess up a good thing? I have to buy pistons regardless why spend the extra 100 bones if I don't have to time will tell, I'll find out tomorrow, completely forgot about it today. I'll be sure to take some pics too.
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If it aint broke don't fix it. The bores still had cross hatching when I got the block, to me that means that the bores are still good, but that's just me. I am trying to avoid all of the machining that I can, i'ts a pain to keep taking it back to the machinist and hear his I-told-you-so speech again and again :P ::) No, but seriously, the bores are fine, why mess up a good thing? I have to buy pistons regardless why spend the extra 100 bones if I don't have to time will tell, I'll find out tomorrow, completely forgot about it today. I'll be sure to take some pics too.
cross hatches or not, i pulled my last 1.5 apart (single owner, never been taken apart, EVER) and it had 125k miles on it, and the bores still had cross hatching in them, and only a slight lip. there was still cross hatching in those cylinders too, so im sure your cross hatching is old also. i just wouldnt half ass the pistons/bores. but if you drop your new pistons in, and there at .001" spec, then run it, but if its any looser, i would bore it and go over size. i just dont see why you are gonna skimp on such an important step (in my eyes) and you are willing to splurge on such un-important things such as a complete aftermarket oil system. i think i would rather bore the block, than go with the oil system if it were me, and if i were on a limited budget. i just dont get your method of thinking sometimes is all...
when i built my last engine, no, i did not bore it. but, it has a piston and rod out of a completely different engine. and the bottom of the bore is broken. it still runs great, but i can tell its not right. it has a cold miss that goes away, and uses some oil, more than i would like. by not boring your engine, you are just asking for lots of blow by, and an engine that burns plenty of oil.
i just wouldnt take the chance unless its still at stock VW spec (or atleast super close for piston to cylinder wall clearance.
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I'm not on a budget build per-se, just frugal "the mods don't like it when I use a certain ethnic word, even though I am one" ;) I will spec it out for sure.
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76.98 thats oversize, and that is what I need 8)
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Brand new Kolbenschmidt 76.98 turbo pistons is what I have. Stamped right across the top of the piston.
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76.98 thats oversize, and that is what I need 8)
whats your bore mic out at? have you checked yet? how tapered are the bores? how is the ridge at the top of the bore?
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hold on, I have to dig up the ol mic 8)
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Ok, I have a set of calipers, best reading I can get says 76.92, what is the best way to get an accurate reading? or am I using the wrong tool for the job? ???
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There is absolutely no ridge at the top of the bore, just to be clear. I gotta be doing something wrong when measuring, it is a digital set of calipers, and yes, I zeroized and calibrated them properly before use.
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Are you using bore gauges?
This style lets you use a dial caliper:
http://cgi.ebay.com/ebaymotors/NEW-TELESCOPING-GAUGE-SET-inside-bore-measuring-tools_W0QQitemZ370334514951QQcmdZViewItemQQptZMotors_Automotive_Tools?hash=item5639a83f07 (http://cgi.ebay.com/ebaymotors/NEW-TELESCOPING-GAUGE-SET-inside-bore-measuring-tools_W0QQitemZ370334514951QQcmdZViewItemQQptZMotors_Automotive_Tools?hash=item5639a83f07)
This style has the gauge built-in:
http://cgi.ebay.com/ebaymotors/PRECISION-ENGINE-CYLINDER-HOLE-DIAL-BORE-GAUGE-GAGE-SET_W0QQitemZ370339278224QQcmdZViewItemQQptZMotors_Automotive_Tools?hash=item5639f0ed90 (http://cgi.ebay.com/ebaymotors/PRECISION-ENGINE-CYLINDER-HOLE-DIAL-BORE-GAUGE-GAGE-SET_W0QQitemZ370339278224QQcmdZViewItemQQptZMotors_Automotive_Tools?hash=item5639f0ed90)
The idea is to take a series of readings in several directions at 3 or more depths on the bore... giving you an accurate picture of mean diameter, taper, etc.
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so in other words, I need to get my machinist to do it for me.... 80 bucks for a guage is not what I was expecting :'( Thanks Vince, I'll figure something out. I want to do this myself, but it seems that that may not be the case.
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Probably a good idea. They are an acquired skill to use as well... in terms of repeatability.... for a one-off handing it off to a guy that does this for a living might make sense.
I have a set but I mostly use them to predict how bad the news from the machinist is likely to be. ::)
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I'll know wed evening :-\ be worried till then :'(