90.5 vs 92 mm

Kubelmann · Post by **Kubelmann** » Wed Jan 22, 2003 8:25 pm

I am in the process of building my motor for my offroad 73 Thing and am trying do decide between 1776 and 1835. Either one will have new Mahle forged istons and jugs, head and cam. Thoughts here are appreciated. Thanks, K-mann

VWJason · Post by **VWJason** » Wed Jan 22, 2003 8:51 pm

90.5s or if you want 94s. Forget the 92s even exist. They are not a viable option if you want the motor to last. They overheat too easily, are thin and are subject to warpage causing excissive blowbby.

Disclaimer: If you read this and you are running 92s and have not experienced any problems then you and God are on good terms then.

maxyboyvw · Post by **maxyboyvw** » Wed Jan 22, 2003 9:11 pm

<BLOCKQUOTE>quote:<HR>Originally posted by VWJason:
...
Disclaimer: If you read this and you are running 92s and have not experienced any problems then you and God are on good terms then.

<HR></BLOCKQUOTE>

...or you drive like the old lady down the street!

90.5s or 94s are better choices than the 92, which have thinner cylinders. but hell, i'm sticking with the stock 85.5s!

scottk · Post by **scottk** » Wed Jan 22, 2003 11:13 pm

I think the best choice are the 92's... but only if they are the machine in, thick walled kind. You have to machine your case for 94's. www.lnengineering.com sells um... 94's are good too..

Scott

74baja1915 · Post by **74baja1915** » Wed Jan 22, 2003 11:32 pm

if you have to get the case machined then go for the 94's

why pay the same money for less stuff(cc)?!?!

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If its not broke don't fix it, but if it can be made better by all means do it!

JC-ATL · Post by **JC-ATL** » Thu Jan 23, 2003 5:34 am

I've never seen a machine-in 92. Does anyone make them? I'm assuming they'd use the same outer bore as a 94, similar to the relationship between the machine-in 88s and 90.5s?

That being said, I'd likely go for the 94s. In fact, I just did. Building up a 1915 now.

Post by **Marc** » Thu Jan 23, 2003 6:19 am

<BLOCKQUOTE>quote:<HR>Originally posted by JC-ATL:
I've never seen a machine-in 92. Does anyone make them? <HR></BLOCKQUOTE>

The link Keith gave above takes you right to one of them. Bring $2699 (but the shipping is free!)
I'm amused by your terminology. 92s are not "slip-in" for 90.5 register, it's the other way around. The first 88s required machining case & heads slightly; 90.5s took a bit more, and 92s (the furthest anyone could conceive of safely cutting back then) a bit more yet. Those old-school 88s & 90.5s had cylinderwall thicknesses comparable to 92s; after a while it dawned on people that by downsizing the bore one step in relation to the case & head sizes, the resultant thicker cylinders would make it easier to build an engine with a little tolerance for being overheated once or twice without destroying the cylinders. IMO the downside to 94s is the amount of material removed from case & heads to run them - the cylinderwall thickness is adequate but not ample (about .006" thicker than an 87). A "thickwall" 92 jug would be less prone to cracking & distortion than anything on the market except 88s so I can see the attraction but personally my first choice would be to stay with 90.5s and stroke if 1775 isn't big enough.

James Buchan · Post by **James Buchan** » Thu Jan 23, 2003 6:55 am

I've ran 92's a few times and never had a problem... The "problems" people experience are most likley user/builder errors... If its built right and looked after it will be fine.

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AKA "Cpt Zoomy"

Post by **sparkmaster1** » Thu Jan 23, 2003 7:34 pm

Where are you located? I have both you can look at them side by side and see the difference. Thicker is better. Tim

Kubelmann · Post by **Kubelmann** » Thu Jan 23, 2003 8:07 pm

Great feedback here!! Jake Raby told me today that he has not done the 92(1835 in 9 years (old school) He suggested going for 1904 or 2007 for my Thing. Many good points made here about where the bulk of my experience comes from. I am not new just not recent. Some feedback about current stroker VW vs 94 mm would be good for me now. Thanks, K-mann

Bob Ingman · Post by **Bob Ingman** » Fri Jan 24, 2003 7:07 am

Cpt Zoomy, Kubelman lives in Colorado. Hot and hilly (as in Rocky Mountains). The Thing is close in weight to a bus. 92`s there are not the same as 92`s in BC. Good luck. Bob Ingman

Post by **Marc** » Fri Jan 24, 2003 8:17 am

<BLOCKQUOTE>quote:<HR>Originally posted by James Buchan:
The "problems" people experience are most likley user/builder errors... If its built right and looked after it will be fine.
<HR></BLOCKQUOTE>

So, none of us know what we're doing then?
...or is it that "fine" is a subjective term?

James Buchan · Post by **James Buchan** » Fri Jan 24, 2003 9:07 am

Good call Bob, I didn't take that into consideration. I am blessed with fairly consistant weather here...Just wet alot of the time

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AKA "Cpt Zoomy"

James Buchan · Post by **James Buchan** » Fri Jan 24, 2003 9:11 am

Marc, what I am saying is that with consistant maintanence and use of all the stock cooling I have yet to experience any problems using 92's - which I have on a number of engines.

I now run 69x94 which again I feel if looked after will be fine.
I know people in the past have had problems with 92's but I haven't so that is all I was saying.

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AKA "Cpt Zoomy"

Post by **Marc** » Fri Jan 24, 2003 10:27 am

<BLOCKQUOTE>quote:<HR>Originally posted by James Buchan:
I know people in the past have had problems with 92's but I haven't...
<HR></BLOCKQUOTE>

OK, but I still wouldn't recommend them for a heavy vehicle like a Thing, the choice between them and 90.5s is a no-brainer.
IMO the only place for them is in sand toys & such, just like slip-in 88s; I've had reasonably good luck using them in circle-track engines too but that's attributable to the methanol fuel and shouldn't be considered an endorsement.