yet another reason to avoid doing top end work

crassius

crassius

Well-Known Member
Just got a couple 32mm cylinders in & wondered to what the 32mm referred. 1st one I checked had both transfer ports 32mm down from head. 2nd one was at 33mm. Checked some used cyls laying around and found many with one trans port at 32mm and other at 36mm. Others were at 34mm for both. The new ones are about 1.5mm taller than the others measuring from head gasket seat to base gasket seat.

For me to do a top end with parts & labor, it is about $20 less than if I just sell them a whole new motor - I think that's what I'll do.

Just wanted to have parts available for them as likes to play with their motors, but not sure how to sell the mismatched stuff I'm getting.
 
thanx, that will differentiate these from the 40mm intakes

I wish they'd sell these with a port map, as I have no two with same port depths.
 
There are also some that have a 35m intake stud spacing and I got a few of them from one of my sources that still sells the old style flat top transfer jugs. These jug's are great for making power but the 35m stud spacing also means slotting the holes on the intakes so they'll go on whether they're stock or performance intakes since everyone making performance intakes sell them as 32 or 40mm, I've had to slot these or just cut the ends off the flange to get them to fit.
These are the ones sold on ebay as performance cylinders, they are basically the old style with the flat top transfer ports... as far as "bolt on and go" performance is concerned, they're about the same but tend to rev a bit higher, they still need to be ported for any real performance, but might gain a mph or 2 if bolted on as is only due to the transfer style.
 
most of the really gutless motors I've seen have ports much lower than others which restricts the flow - certainly don't want to end up there with these cylinders
 
Yup... you want the transfers and exhaust ports up high in the cylinder, the lower ports tend to make for some gutless engines. I usually make a 1mm thick spacer to put at the base sandwiched between a set of copper gaskets to raise the jug and get the ports into this sweet spot, then I deck down the top of the jug so the piston is in the same place at tdc. This is for performance engines but could be done to any engine for a little more mid range on up power. Putting the spacer at the base does the same thing as raising the exhaust and transfer roofs but without cutting into the cylinder ports and one can make a spacer in just about any reasonable thickness to correct minor port timing issues, but the ones with the mission matched transfers, they can be saved by raising the low roof to match the high roof, but you'll spend a lot of time matching them up since the roof needs to be at the same hight And the angle it blows into the cylinder needs to be the same as well.. too bad you can't just send these back for a refund since you'd probably spend more shipping them back...
 
yeah, tried one and found it damaged at cylinder skirt so piston got gouged as I tried to push it thru - took 1/16in off skirt, re-chamfered and re-honed cyl, and polished gouge out of piston - seems good now & ports look to be within 1mm of original, so hoping it runs well
 
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