strokersquid Posted April 27, 2010 Report Share Posted April 27, 2010 I HAVE TO REBUILD A STROKER ENGINE BUT I'M NOT SURE WHAT KIND OF WISECO CRANK WAS TAKEN OUT AS IT IS OUT OF SPEC AND NEEDS REPLACING.ANYBODY KNOW HOW TO TELL IF ITS JUST A STROKER CRANK OR IS IT A LONG ROD STROKER ? IT SEEM SOME MANUFACTURER'S STANDARD RODS SAY 29L ON THEM. THIS CRANK DOES NOT. Quote Link to comment Share on other sites More sharing options...
locogato11283 Posted April 27, 2010 Report Share Posted April 27, 2010 what pistons were in it? it will tell you on top of the piston. you may have to wire wheel the carbon off.. Quote Link to comment Share on other sites More sharing options...
strokersquid Posted April 27, 2010 Author Report Share Posted April 27, 2010 what pistons were in it? it will tell you on top of the piston. you may have to wire wheel the carbon off.. WSM on 2nd bore. this should mean it is standard rod, but i didn't know wiseco made a 4mm stroker thats not a long rod and the engine builder thinks its a long rod.thats why i'm looking for something that would confirm its a stock rod length. it has a plate and the combustion chambers are cut 2mm more into the head so i'm not sure what the original owner did Quote Link to comment Share on other sites More sharing options...
Wildcardracing Posted April 29, 2010 Report Share Posted April 29, 2010 Piston part numbers would be the fastest and easiest route. But, if you can't get that then you can either measure the rods from pin center to pin center or get a measurement from the top of the piston pin bore to the edge of the piston crown. -Brandon Quote Link to comment Share on other sites More sharing options...
strokersquid Posted April 29, 2010 Author Report Share Posted April 29, 2010 Piston part numbers would be the fastest and easiest route. But, if you can't get that then you can either measure the rods from pin center to pin center or get a measurement from the top of the piston pin bore to the edge of the piston crown. -Brandon engine builder insists they are WSM pistons. WSM does not to my knowledge make long rod compatible pistons, right ? Is it even possible to use regular pistons on a long rod crank ? This engine had a head cut 2mm deeper and the pistons came above the cylinder edge at TDC. the head gasket was a single thickness metal one. Usually one puts in a spacer plate and the rest bolts on without mods. This is also an RZ powervalve engine though this shouldn't make much difference. Quote Link to comment Share on other sites More sharing options...
Snopczynski Posted April 29, 2010 Report Share Posted April 29, 2010 engine builder insists they are WSM pistons. WSM does not to my knowledge make long rod compatible pistons, right ? Is it even possible to use regular pistons on a long rod crank ? This engine had a head cut 2mm deeper and the pistons came above the cylinder edge at TDC. the head gasket was a single thickness metal one. Usually one puts in a spacer plate and the rest bolts on without mods. This is also an RZ powervalve engine though this shouldn't make much difference. I think blaster pistons work. Quote Link to comment Share on other sites More sharing options...
Larry's Shee Posted April 29, 2010 Report Share Posted April 29, 2010 HMMMMMMMMMMMM, so if your builder doesn't know and can't figure it out .............. Quote Link to comment Share on other sites More sharing options...
methyman Posted April 29, 2010 Report Share Posted April 29, 2010 (edited) WSM makes a stroker piston for the long rod cranks. Tony Dukas Racing sells them. You need to measure the piston pin height and compare it to a stock piston. The 4mm short rod crank is only made by Vito's and everyone else crank is a long rod 4mm stroker. The short rod crank you can use stock style Wiseco 513M0XXXX size piston or a WSM piston. With a long rod you need to use a shorter piston like a Wiseco 795M0XXXX. I hope this helps a little bit. TDR Part numbers WSM stroker piston (long rod) # 16-5790 WSM stock style piston (short rod) # 16-5788 Edited April 29, 2010 by methyman Quote Link to comment Share on other sites More sharing options...
No Limit Powersports Posted April 29, 2010 Report Share Posted April 29, 2010 There is no reason that they would use a plate and recessed domes unless they didn't use the right piston. You need to measure the crank do not rely on the piston spec to tell you what you got. Surely your builder has some calipers?? I would also degree the motor out because if its ported you might not be able to switch to the correct piston if they did something weird. Quote Link to comment Share on other sites More sharing options...
AKheathen Posted April 29, 2010 Report Share Posted April 29, 2010 only thing i can think is the crank is a custom make......if the rods say 29L then that is yamaha rods...if it needs a plate, and domes, then i'll bet it's more than 4mill, shortrod, and all custom. measure the stroke, and rod length, that's about all you can do at this point, imo Quote Link to comment Share on other sites More sharing options...
strokersquid Posted May 1, 2010 Author Report Share Posted May 1, 2010 it is a long rod 4mm wiseco crank. On the rz forum they gave me the rod length of the rd 400 ( 5.810" small to large end) and thats it on the nose.I have a new wiseco long rod 4mm crank and it matches in all dimensions.I think the previous guy didnt want to use the wiseco 795 pistons since they cost so much so he used standard ones and recessed the head and put in a thicker base plate to compensate. that sound right ? unfortunately my builder bored the cylinders to match a set of standard wisecos and as long as this combo works ill redo it that way, though long rod special pistons,standard base plate and head would probably be better. used this builder since hes local, i had what i thought were the correct parts and i didnt think i would find this mess when i cracked the head ! Quote Link to comment Share on other sites More sharing options...
strokersquid Posted May 1, 2010 Author Report Share Posted May 1, 2010 oops, i didnt mean the head is cracked, only that i didnt know what was inside until he disassembled it!!! Quote Link to comment Share on other sites More sharing options...
AKheathen Posted May 1, 2010 Report Share Posted May 1, 2010 lol, whe got it......so, you measured the stroke out? or just rod length? how recessed are the domes? mabey 3mm, which would be too much to run 4mill with the right pistons Quote Link to comment Share on other sites More sharing options...
strokersquid Posted May 2, 2010 Author Report Share Posted May 2, 2010 lol, whe got it......so, you measured the stroke out? or just rod length? how recessed are the domes? mabey 3mm, which would be too much to run 4mill with the right pistons the head recess appears to be about 2mm. the rod length is 5.81" where stock is 5.6 or so ( measured it on a stock crank i have ). you can tell its a 4mm by how far the crank pin is from the web edge,that is a stroker is closer to the web edge than stock. Quote Link to comment Share on other sites More sharing options...
AKheathen Posted May 2, 2010 Report Share Posted May 2, 2010 well, then you have only established that it is a long rod....as for the edge of the webbing, you cannot rely on distance to the outter circumference of the webbing, as they vary with different cranks, otherwise, 10 mill would just about be out of the webbing, and verry unballanced. seriously, though, you need to measure the rod pin center distance from crank center...you can use the bearing as a reference point. if it has longrod pistons, only 4mill domes, and a 4mill 1.5mm plate, then it could possibly be a 7 mill.......you won't know untill you measure, because even running the wrong pistons, 2mm recessed domes and 1.5mm plate will not clear, even on stock stroke Quote Link to comment Share on other sites More sharing options...
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