1835 bay window engine

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lil_azza
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1835 bay window engine

Post by lil_azza » Sun Apr 23, 2017 1:10 am

Ok so im building a 1835 iv got a set of 20 odd year old new barrels and pistons at 92mm
Of the good quality variety
And a progressive carb and manifold kit
I want torque not out and out power i just want to climb hills a bit safer and quicker
Iv got a set of 1600 heads that are cut ready
What cam a w100?
Do i go 1:25 rockers?
Stock pushrods?
Thankyou

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Piledriver
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Re: 1835 bay window engine

Post by Piledriver » Sun Apr 23, 2017 5:51 pm

On a Bay, I'd look harder at swapping what you have for the thickwall 92s, or even go 90.5 since everythings machined for thinwall 92s.
(Thickwall 88s are IIRC also same exterior sizes, not sure if anybody still makes those)
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Marc
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Re: 1835 bay window engine

Post by Marc » Sun Apr 23, 2017 8:21 pm

I really frown on the idea of using classic "thinwall" 92s, especially on a heavy vehicle. They don't stay round under thermal cycling and the rings are constantly trying to break into a moving target. The sealing area is so narrow that they can actually cut into the head, causing a loss of head-stud torque. I've used 'em for racecar engines and you do get a little more power from the added displacement compared to 90.5s at first, but by 20K miles or so on the street it's a push - plus the 92s will have more blowby and oil consumption.
When AA first came out with their "thickwall" 92s they had the same O.D. top & bottom as 94s which gave them ample wall thickness (~.014" greater than stock 85.5s), but I never liked the idea of whacking more material than necessary out of the case - I would take them to my machinist and have him cut the bottom spigots down to the "classic" 92/late 90.5 size. When honing afterwards we discovered that it unexpectedly caused the I.D. to constrict slightly at the bottom. Cost about $50 to have them cut down and Tru-honed. I asked AA if they could just make them that way, and apparently enough others did too - they now offer them in both lower-spigot diameters. Their "M" version are the originals with 97.25mm O.D. and the "K" are 96mm. Both require that the heads be opened up to the "94" diameter. You can buy cylinders-only for ~$140 a set; that (plus the cost of opening the heads up) is money well-spent. Next-best choice would be the late 90.5s - they're nearly as thick as stockers (~.015" less) but have proven to have decent durability in a Bus.

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Re: 1835 bay window engine

Post by Marc » Sun Apr 23, 2017 8:38 pm

88s have come in 4 different versions over the years; the slip-ins are a joke, the long-obsolete early machine-ins were about as thick as stock. The late machine-ins were made with the same O.D.s as early 90.5s (smaller than late 90.5/classic 92) and they have generously thick walls, but they too are obsolescent these days. Bugpack used to offer cylinder-base shims for that size, but since EMPI took them over they've been dropped. AA made cylinders in that size for a while but demand was so low that they stopped - now they make some that are "classic 92" O.D. at the top and stock O.D. at the bottom. Those are excellent if you have a sound bottom end and want to bump the displacement to the limit without splitting the case for machining - but other than those, I think we can consider 88s to be a dead-end anymore.
I've had a couple of cases which were cut for the odd-ball late-machine 88 size; rather than blow money on opening them up to the late 90.5/classic 92 diameter I just have late 90.5 cylinders turned down to fit. You could even do the same with 92 cylinders and still have ~.040" thick lower spigots like the slip-in 88s (or the AA TW88s) have. BUT, you'll still be scrounging if you find that barrel shims are needed since nobody makes them that size anymore...even Gene Berg, who still sell 88mm piston/cylinder sets in that size.

lil_azza
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Re: 1835 bay window engine

Post by lil_azza » Tue Apr 25, 2017 10:26 am

Ok thanks guys so i think iv sourced a set of 90.5 so looks like il just go 1776 with a w100 and stock valvetrain ? Stock springs etc justbfull flow and a progressive carb?
Should be fine for what im after dont u think? Chers

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Re: 1835 bay window engine

Post by Piledriver » Tue Apr 25, 2017 1:13 pm

Dual Kadrons would be a huge upgrade over the progressive, get a decent linkage to go with them.
If you keep the progressive, make very sure the manifold heat works 100%.
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Re: 1835 bay window engine

Post by Marc » Tue Apr 25, 2017 3:30 pm

Piledriver wrote:
Tue Apr 25, 2017 1:13 pm
...If you keep the progressive, make very sure the manifold heat works 100%.
Cannot overemphasize how important that it. There exist "deluxe" proggy manifolds that have a more elaborate heatriser setup to warm the intake better, but even with those it can still be a problem with an aftermarket exhaust which doesn't provide as much preheat flow as a stock muffler.
With a cold manifold you'll have a nasty "flat spot" on step-off; jetting richer and maximizing the accelerator pump shot will help but both hurt mileage and if taken to extreme will even wash down the cylinder walls. Get ahead of it by ensuring that the manifold gets as warm as possible; consider fabricating an adapter to connect the stock thermostatic aircleaner or at least cobble up a connection which brings warm air to the proggy's aircleaner that you can attach in the cooler months. That can be as simple as a piece of sheetmetal which fits along the outside of the element on one side, with a hole in it and a short 2" tube welded/brazed on where the warmair hose can be slipped on.

A more elaborate adapter to connect the stock aircleaner could be something similar to this: https://www.thesamba.com/vw/forum/viewt ... p?t=542166 Yes, it's more restrictive but it should be adequate for a 1775 that's not being revved beyond ~4000 RPM.

Redline makes an adapter which you could use but it's rather spendy: http://www.carburetion.com/Products/Pro ... =99010.357

And there's this baseplate which you could use as a starting point to build your own: http://www.carburetion.com/Products/Pro ... =99010.457

http://www.aircooled.net/making-weber-p ... vw-engine/

lil_azza
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Re: 1835 bay window engine

Post by lil_azza » Tue Apr 25, 2017 4:02 pm

Ok thankyou very much for ur input the carb im getting is off a mate thats all been setup on a rolling road for a 1776
Il check before i get it off him its the heat riser manifold and thanks for the link id like to use the oil bath if i could
Would a stock exhaust be ok?

lil_azza
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Re: 1835 bay window engine

Post by lil_azza » Tue Apr 25, 2017 4:02 pm

Ok thankyou very much for ur input the carb im getting is off a mate thats all been setup on a rolling road for a 1776
Il check before i get it off him its the heat riser manifold and thanks for the link id like to use the oil bath if i could
Would a stock exhaust be ok?

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Re: 1835 bay window engine

Post by Piledriver » Tue Apr 25, 2017 9:05 pm

A quality stock exhaust would be preferable for the heat risers, probably wouldn't hurt a 1776 much.
Get the big tapered peashooters for it tho.
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Re: 1835 bay window engine

Post by sideshow » Tue Apr 25, 2017 9:34 pm

Tapered peashooters will not work with a bus apron/bumper. I'm not sure what the upgrade for the tail pipe is. I've been curious if a beetle muffler and !two bus tail pipes could be made to work well.

That off road to progressive adapter looks like the trick, never used one as I think you are better off with duals. I've adapted basically CBPerformance dual blow through bits to oil bath without regret. Eventually I am going to try a single IDF to oil bath, I expect that to work well also.
Yeah some may call it overkill, but you can't have too much overkill.

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