Cylinder base shims/spacers for 88mm

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Marc
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Cylinder base shims/spacers for 88mm

Post by Marc » Sun Sep 04, 2016 2:57 pm

Anyone know of a source for cylinder shims for thickwall machine-88s? Early 90.5 are the same diameter also...
I.D. needs to be in the 94.4 to 94.75mm range - late 90.5/classic 92s are too large at 96mm+.

All I've been able to find online is shims for slip-in 88s, which are of course the same as stock (~90mm).
Berg used to sell them (at a price) but they've suspended production.

I've got a couple of cases cut to that size which I may have to get recut to something more common if I can't find any shims.

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Re: Cylinder base shims/spacers for 88mm

Post by sideshow » Thu Sep 08, 2016 8:03 am

BugPack 4558-X0? Hmmm, 35x48 px seems too large to post...just image dust covered retail packed cards appears to be three (well the 4th is marked 83mm 40hp) at a nearby ACVW retail store
Yeah some may call it overkill, but you can't have too much overkill.

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Re: Cylinder base shims/spacers for 88mm

Post by ps2375 » Thu Sep 08, 2016 11:03 am


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Re: Cylinder base shims/spacers for 88mm

Post by Marc » Thu Sep 08, 2016 3:58 pm

Nope, they only have the 90, 96, & 97.25mm I.D. shims.

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Re: Cylinder base shims/spacers for 88mm

Post by Marc » Thu Sep 08, 2016 4:10 pm

sideshow wrote:BugPack 4558-X0? Hmmm, 35x48 px seems too large to post...just image dust covered retail packed cards appears to be three (well the 4th is marked 83mm 40hp) at a nearby ACVW retail store
Those are probably the ones I'm looking for. Googling 4558 I found one place online (in Sweden) that lists them, for 88mm cylinders. http://slidegur.com/doc/4900552/motordelar-sidorna-1 (page 3)

Only possible problem would be if they were for the first machine-in 88s made, which are 91.5mm O.D. rather than 94.4mm. Those haven't been made in decades, although I believe Berg's still sitting on some.

Don't know why they can't just publish the actual I.D. for the benefit of people who know what they're looking for. If you would, next time you're there could you see if they can measure the I.D.? 91.5mm = 3.602", 94.4mm = 3.717". The demand for 94.4mm shims is all but dried-up and they'll probably continue to collect dust until they end up on the discount table someday if I don't buy `em ;)

83mm BB40 cylinders are slip-ins, they have the same 87mm O.D. as stock 40HP 77s ... odd that they'd mark them like that, perhaps they figured the only folks who'd need 'em would be those building a BB40.

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Re: Cylinder base shims/spacers for 88mm

Post by Marc » Thu Sep 08, 2016 4:59 pm

Hmmmm....anyone have some copper headgaskets for 94mm bore they can measure the actual I.D. of? If it's close to what I'm after I suppose I could open 'em up slightly with a flap wheel.

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Re: Cylinder base shims/spacers for 88mm

Post by H2OSB » Fri Sep 09, 2016 3:10 pm

Sorry if this is an obvious answer, but have you tried contacting companies who make machine in 88s, like AA?

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Re: Cylinder base shims/spacers for 88mm

Post by Marc » Fri Sep 09, 2016 3:22 pm

AA was one of the first places I looked. Like everybody else, they only have the ones with 90, 96, or 97.25mm I.D.

The only 88 cylinders AA makes are slip-ins (even their thickwalls, which fit heads opened up to 98mm) are the stock 90mm O.D. at the case.

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Re: Cylinder base shims/spacers for 88mm

Post by H2OSB » Fri Sep 09, 2016 4:03 pm

Last edited by H2OSB on Fri Sep 09, 2016 4:12 pm, edited 2 times in total.

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Re: Cylinder base shims/spacers for 88mm

Post by H2OSB » Fri Sep 09, 2016 4:06 pm

All of those different shims on the AA site and none of those will work?

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Re: Cylinder base shims/spacers for 88mm

Post by Marc » Fri Sep 09, 2016 5:25 pm

I've already explained this, but I'll try going slower....please pay attention this time.

The first machine-in 88s, which haven't been available for decades (other than from Gene Berg - GB003 thru GB006) are 91.5mm at the case and 94.4mm at the head.

The first machine-in 90.5s, also obsolescent, were 94.4mm at the case and 97mm at the head (GB012/012D).

Until the recent introduction of "thickwall" 92s that fit case & heads machined for 94s (97.25/101.1mm, "M" code at AA), 92s have always been 96mm at the case and 98mm at the head. AA also makes a variant "K" code which is 96mm at the case and 101.1mm at the head.

Years ago someone realized that they could create 88s and 90.5s with thicker walls if they used the next-size-up cylinder O.D.s - that gave us 88s that are 94.4mm at the case and 97mm at the head, and 90.5s that are 96mm at the case and 98mm at the head.

AA has introduced "slip-in thickwall" 88s which retain the stock 90mm diameter at the case, but require machinework to the heads to open them up to the "late 90.5/classic 92" size, 98mm.

The shims I seek are for the early 90.5 and late (but pre-AA) 88. 94.4 at the case, 97mm at the head. It appears that nobody (even Berg) is still producing these, so I need to find some N.O.S. ones collecting dust somewhere.

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Re: Cylinder base shims/spacers for 88mm

Post by H2OSB » Fri Sep 09, 2016 5:39 pm

Thanks for the explanation but I was just throwing that out. Nothing like douchey sarcasm.

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Re: Cylinder base shims/spacers for 88mm

Post by Marc » Wed Sep 14, 2016 12:57 pm

H2OSB wrote:..Nothing like douchey sarcasm.
Perhaps you missed my post stating that AA did NOT have anything which would fit.

So far I've found one set of .060" on a tip I got at a Facebook group, and a machinist who thinks he may have some but won't be able to look until he's back in town next week. Hoping he comes through, he said he'd be happy to be rid of them since he'll probably never use 'em :D


For the benefit of anyone searching this topic in the future: I have a set of wide blanchard-ground .160" spacers that'll work for second-gen machine-88s/early 90.5s. Also fit ISS 90s; not sure about NPR. They measure almost 96mm I.D. but are too small for late 90.5s/classic 92s...although one could probably open them up with a flap wheel if need be.
Don't have any immediate plans to use them so odds are they'll be around if you need 'em someday.

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Re: Cylinder base shims/spacers for 88mm

Post by Marc » Tue Sep 27, 2016 6:03 pm

My machinist had a couple of used .080" shims and a passle of ~.034"s (I bought the .080s and 4 of the .034s) as well as some .010/.020/.030/.060s still in Bugpack packaging if anyone else needs some....near Seattle, contact me if you're looking.

Talked to Kona Fleming, he said that AA once did make the 2nd-gen machine 88s but demand was so low that they dropped them from their lineup years ago. He also said that they could make a run of 90.5s that are 98mm top/94.4mm bottom but they'd need a preorder of ~100 sets to be bothered. So it looks like having "normal" 98/96mm 90.5 jugs turned down to 98/94.4mm is going to be the best bet if you want to avoid recutting a 94.4mm case (should be a <$50 job). Besides the added displacement, "B" pistons are readily available for 90.5s, unlike the 88s.
Of course you still might need the obsolescent shims, but I put a bug in Kona's ear that they could corner the market on those if they'd start making them. ISS 90s are ~94.6mm and can use most "94.4mm" shims as well (I've even shoehorned those into "94.4mm" cases with just a little flap-wheel massaging).

A side note: Slip-in 88s have a lower spigot that's only ~1mm thick - so thin that you can cut yourself on the edge (due to the chamfer) and fragile as heck until assembled...but it's not a problem in operation since that area isn't highly stressed - at least with a stock/moderate stroke. This means that you could also have 92s (either the classic 98/96mm ones or the AA thickwalls that are 101.1/97.25mm "M" or 101.1/96mm "K") cut down to 94.4mm without the lower spigot ending up any thinner than that of the slip-in 88s, if you wanted to ;) ....I'm opting for the 90.5 bore, but 92 is feasible.

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