90mm Cylinders

[triguy]

I am looKing at reusing these cylinders. They all measure OK but have some pitting at the bottom of the cylinder. It seems to be more where the piston does not ever contact the cylinder. Is this OK?

Thanks Neil

[Lapkritis]

Can you feel them with your finger nail?

Also noting the cross hatch is very low angle... almost perpendicular to the cylinder bore. This should be 45* in my experience for oiling and ring purposes.

[triguy]

I think this is still the factory marks in the cylinder. I have just cleaned them with some red scotchbight pads.

[triguy]

The pitts are pretty small in size so you can't get your finger nail in there but you can feel them when a small ball probe. They are mostly located in the area where the piston never touches. I think this is the area that sometimes gets cut out. The cylinder measure ok, the larges measurement I found in any of the cylinder is 90.071mm and the smallest is 90.038mm I am thinking of ordering new JE pistons at 89.097mm for size but I am a little unsure of clearance.

[Lapkritis]

Might be light corrosion due to being parked for a length of time. If it is only at the bottom then probably low risk in running these.

What is the interest in JE pistons? Just looking for stock replacement or performance as well?


-Andrew

[Lapkritis]

Looked at your pictures again and the cluster pitting in the second is half way through the jug height. I would be concerned if this was caused by corrosion as returning the cylinder to service could loosen more of the plating. I would recommend replating by professional shop now rather than going through the pains soon after reassembly.

-Andrew

[triguy]

I am looking at putting JE's in so I can run an E-cam in my 2.7 I am just wanting to go to 9.5 compresion with the mag case. I have been really struggling with comitting to these cylinders I know they will work just fine but ???

[Lapkritis]

If you have questions on the plating then now would be the time. Between the pits and the tool marks being incorrect I would service them as I plan to drive my engine for a decade or better before the next service. If this is going to be a garage queen or museum piece then it might not matter as much if the plating isn't perfect in there.

Alternate Replating service:

http://www.alssnowmobile.com/

$195 per jug, ~4wk turn-around time. You will need to provide specs these should be plated to; bore size, piston size and suggested ring gap would be useful to have on hand. The jugs are rather porous so some light pock marks will always be present. These guys won't be able to repair/weld casting damage but they can replate to spec. (802)-487-1000 x111 is Shawn who handles all these as they come in.