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Mon Jan 27, 2020 5:15 pm

i was wondering whis done some mini stroker builds , like stoke 85.5 bore and a 74, 76, or 78 crank ? and how'd you like it?

Mon Jan 27, 2020 6:35 pm

Why would anyone do that?
In my POV a 90.5x82 is a mini stroker.
As they used to say in the chain gang, “Don’t come out half steppin”!

Mon Jan 27, 2020 7:29 pm

The only time mini strokers make sense is when people are intimidated by having machine work done for larger pistons.

Power is in the heads. When you use larger pistons you can install larger valves.

Short stroke engines rev faster then long stroke engines.

Mon Jan 27, 2020 8:05 pm

I have built my fair share of ministrokers. I will say this much. If you build say a 1745 versus a 1776 you can change the behaviure of the engine quite a bit, even with using basicly the same parts.
That said, unless you want an engine that revs higher than what a balanced stock rotating assembly likes, - or you need to buy a new crank anyway, the ministroker is not worth the extra money over a 1776 in general.
But it all depends. Some combo´s work very well, other set ups are only mediocre.

Mon Jan 27, 2020 9:10 pm

This topic gets discussed fairly regularly it seems. In my case it was because was interested in seeing if anyone had used dished pistons so the squish could be set tight and still keep the CR in bounds.

A guy does offer flattops in 86mm bore. His link is in the thread below.

https://www.thesamba.com/vw/forum/viewtopic.php?t=728801&highlight=

Thu Jan 30, 2020 10:00 am

richardcraineum wrote: i was wondering whis done some mini stroker builds , like stoke 85.5 bore and a 74, 76, or 78 crank ? and how'd you like it?

adding stroke always adds torque and if it's a daily driver or a stock or close to stock engine, will help make the car more drivable and help fuel economy.

also the smaller stroker engines such as these combinations, look to be far easier to assemble and keep stock dimensions, engine width, pushrod geometry, etc.

A good starting point if the person building it is a newcomer or first time builder

I'm planning on either the 76mm or 78m with the 'B' pistons as this will be my first VW build.

mine will run the stock carb (pict 30) and likely stock dual port heads and run in the stock rev range.

while I don't expect it to become some tire smoking rocket, and that's not what I want, I don't doubt it'll outpull a stock engine

http://www.aircooled.net/vw-type-1-mileage-engine-mpg/

that will be what I build. I did something similar to this with a datsun and it makes a real difference.

whether or not someone likes an engine with a stroke setup such as these depends on what the individual is wanting to accomplish.

Thu Jan 30, 2020 10:49 am

atticus finch wrote:
adding stroke always adds torque No.
if it's a daily driver or a stock or close to stock engine, will help make the car more drivable and help fuel economy. Yes, because you move the torque around with different stroke and Rod ratios

also the smaller stroker engines such as these combinations, look to be far easier to assemble and keep stock dimensions, engine width, pushrod geometry, etc. Compared to what?

A good starting point if the person building it is a newcomer or first time builder

I'm planning on either the 76mm or 78m with the 'B' pistons as this will be my first VW build. Yes, with the right parts these combo´s can go together reasonably easy. One wrong choice and they are as "problematic" as the rest of the bunch.

mine will run the stock carb (pict 30) and likely stock dual port heads and run in the stock rev range.

while I don't expect it to become some tire smoking rocket, and that's not what I want, I don't doubt it'll outpull a stock engine
It will. But frankly, anything above approx. 1700 cc is not really worth it if the engine is to be fed with a 30 pict. The engine simply can´t breathe unless you go radical on cam & lift, and then the engine will not be as polite as you would want it to.
With a modified 34 Solex its a different matter. Then you can easily reach significantly higher power outputs. And the thing about the 34 Pict´s "not being fuel efficient" is a bunch of cr*p. That is just a matter of figuring out how to adjust it. But is is correct that on a 15/1600 cc engine the 30 is easier to get to run decent. On a large displacem,ent engine, not so.

http://www.aircooled.net/vw-type-1-mileage-engine-mpg/

that will be what I build. I did something similar to this with a datsun and it makes a real difference.

whether or not someone likes an engine with a stroke setup such as these depends on what the individual is wanting to accomplish.

Thu Jan 30, 2020 11:58 am

atticus finch wrote: will help make the car more drivable and help fuel

A stock 1600 with dual carbs (and stock 034 SVDA) will get better MPG and probably more HP/torque than the 1700-1800cc mini stroker with a stock Pic 30, and will be just as drivable.

Thu Jan 30, 2020 1:01 pm

my first vw build I built a 1874 cc 78.8x 87. worked awesome. I didnt know if I would even like driving a bug. so i just get a set of heads(mofoco 042) and scat crank(we were scat dealer, lots of v8 stuff), total seal rings( also a dealer for them) and a set of cb unitec rods. so it was a somewhat cheep build, worked great. I ren it for about 3 years then put in the 2332 I built and reworked the 1874 into a 2028 cc. now days I wuldent do it again,I would just build a 2332 or 2387 or bigger. my 2400 cc gm ecotec with 88 bore and 98 stroke(I think thats what it is) has shit for torque.and poop for power.... about the same as my 2028 vw..or less. and both are 10.4 cr but the gm has over head cams & 16 valves.....and morons designing and tuning them. you cant fix stupid.

Thu Jan 30, 2020 4:24 pm

first, thanks for the input from the experienced.
second, it always irritates the hell out of me when people reply to a question questioning why the poster is asking, and that he should just ditch that idea and do something completely different because they know best. thats one of the reasons STF went south, too many people criticizing a post and not answering the question. you couldn't post one single carb question without miniman bashing carbs and cramming FI down your throat.
now having said that i though about doing " mini strokers" because i have enough parts laying around to build 6 or 7 stockish engines and id like to get rid of some parts. i cant get rid of stock parts if i go out buying new p&c's and everything else can i? so instead of just building 1600's why not stroke em a little to make something different. and not everybody wants to go from a 1600 to 2276 , i got a couple buddies that just want something a little more than stock

Thu Jan 30, 2020 6:23 pm

Unless you’re building an engine for a friend that knows your ability as an engine builder, building/selling engines can be a crapshoot. Too many shade tree mechanics that shouldn’t be building engines have created a bad biased rep for anyone that IS capable of building a nice engine. Unless you’re building a turn key engine in the back of a buggy, that could be test driven/heard run, and simply unbolted/dropped at the time of the sale, most people are skeptical.

The only reason I would build a small stroke/bore engine would be to have a stock “appearing” engine for a show car. Then you are limited by the carb. I’d do a 74x83 for a 40hp engine, or a 76x85 for a 1500/1600. Thick wall 88’s that only need the head opened up, a bump in compression, and a small increase in camshaft will go a long way without added expense of a larger stroke crank.

Thu Jan 30, 2020 6:48 pm

Some people looking to find the easier way to do whatever, probably NOT what you want. But is it a good idea.....IMO YES. The STOCK mutt 1600 that has somehow become the standard.....of mediocracy, isn't very good. :lol:
IMO a 74 or 76 stroke SHOULD HAVE BEEN a factory option. No REAL downside and can be made to fit one way or another.
The reward VS effort isn't great, but overall I think YES it's a great idea, tho just not a very exciting idea. Pistons and cylinders do need a lot of hand work to fit, and shorter rods are not commonly available. But they should be

Thu Jan 30, 2020 9:05 pm

If you can find the 85.5 pistons in "B" pin height, use 5.5 rods, 76mm crank and Bob's you Uncle. Deck height will be about perfect, engine width is the same so everything fits.

Thu Jan 30, 2020 10:46 pm

I’ve driven a baywindow which has a 1745 (85.5x74) with a W110, ported stock heads and 40’s. I must say I really liked it, wasn’t no rocket ship, but moved the bus along very nicely, ideal cruising motor I think. Good idea for people on a bit of a budget I guess.

Thu Jan 30, 2020 11:51 pm

I like small engines. There's nothing wrong with building a 1745 when you could have built a 2.3...and some people find small engines fun. Overtaking cars in traffic with a suped-up beetle is pretty easy....but with a 1200? Now that's rewarding!

80-90 hp is enough to make any beetle more fun than stock, it's twice the hp for the 1300s. A simple, single carb engine is easier & cheaper to operate and maintain than a Webered high-strung engine with inaccessible pugs.

I know you have to push little engines harder to make big torque/horsepower, but the forces remain reasonable. But still, check piston speeds and accelerations, the forces are not comparable between a 74 x 90.5 at 6000 rpm and an 86 x 94 spinning to 7500.

Some guys like Harleys, some guys like 50cc bikes. To each his own. I liked a 1679 i built, and a 1745. Both were waaaay nicer to drive than stock, and good (if not better) mileage, and just as easy to maintain.

And small engines keep the ratio of surfaces which absorb heat to those which radiate heat low. Cooling can only be better, hp is lower.

i drive on snow and ice, and having a very calm, steady, slowly increasing torque curve makes it possible. Engines where just one touch of the gas makes things spin are NOT fun on slippery surfaces, especially with oncoming traffic (and snowplows) in the opposite lane...

Fri Jan 31, 2020 1:59 am

k@rlos wrote: I’ve driven a baywindow which has a 1745 (85.5x74) with a W110, ported stock heads and 40’s. I must say I really liked it, wasn’t no rocket ship, but moved the bus along very nicely, ideal cruising motor I think. Good idea for people on a bit of a budget I guess.
Yes, that is basicly what I am saying. You can move the torque around. From an average standpoint (or should I say mine) a W110 in a regular 1776 cc engine, for a bus, is pushing it unless you are after the 3000+ rpm power. Lower rpm power will suffer. Building a 1745 instead with basicly the same parts will increase usable torque below peak and will also peak some 150-250 rpm lower, which is all good for a bus.
That said, you can make a 1776 do very very close to the same, you only need to use different parts, and that is actually part of the problem, because many people -still- tend to put an engine together based on what´s on sale the day the money burns in the pocket and have difficulties looking past the industry standards with W100/110/120 cams. In a way I understand them, because its not that easy. On the other hand, today we have the internet with LOADS of information. You just have to look for it. Imagine how it was when we began messin´with this back in the 80és.
Back to the ministrokers. If you need the capabilities of an engine like Freebug menthions, - lugging around on slippery surfaces with a smooth torque climb a 1745 is also a good and relaitely easy option due the same facts I stated above.
Coffee break is over. It´s Lotus day today :D

Fri Jan 31, 2020 2:21 pm

richardcraineum wrote: . . . second, it always irritates the hell out of me when people reply to a question questioning why the poster is asking, and that he should just ditch that idea and do something completely different because they know best. . .
Preach it, brother!

I ran into the same problem a few years ago when I began planning my own mini-stroker build. I wanted to build something that would be as efficient and long-lasting as possible, with power output coming in a distant third on the list of priorities. I was toying with the idea of a 76mm stroke by 83mm bore (1645 cc), but since I had never heard of that particular combination before, I asked around for some "expert opinions". Man, if I only had a dollar for every time someone said to me, "Why would you want to do that? You could build a 2180 for the same price." I ended up building that 1645 almost more out of spite than anything else! And when it was all said and done, do you know what shocked me the most about it?

The power output!

After giving it a proper shakedown, I remember being surprised by how close it compared in performance to the 356 Super 90 I had test-driven at work the week before. It wasn't until a couple of years later that I learned the 356 engine was designed with a 74mm stroke by 82.5mm bore- very similar to what I had done. What can I say, great minds think alike! Or, in my case, they just end up re-inventing the wheel.

And for what it's worth, I'm getting 39% thermal efficiency at 3100 RPM (which equates to 40+ mpg and a VERY cool running engine) out of that mini-stroker, and when I put it gear and let it idle down the road at 5 mph, it has enough torque to break the tires loose when I mash the throttle, and enough top-end to push the car down a level road at 103 mph (my official best, so far). Not too shabby for only 1645 cc's.

FreeBug wrote: I like small engines. There's nothing wrong with building a 1745 when you could have built a 2.3...and some people find small engines fun. . . .
This.

A wise man once said, "It's better to have a slow car and drive it like a fast one, than to have a fast car and drive it like a slow one."

The speed limit is only 55 mph. Big numbers are fun, and I totally understand the desire to achieve them, but they're really only useful at the track, or if you're the kind of guy that likes to get into pissing contests with the guy beside you at the stop light, and then brag about it down at the pub. Not that there's anything wrong with that!

FreeBug wrote: And small engines keep the ratio of surfaces which absorb heat to those which radiate heat low. Cooling can only be better, hp is lower. . .
And this.

Small strokes and small pistons might not make big power (unless they're spinning at 15,000 RPM), but they have the potential to be more efficient and long-lasting. Especially those 83mm cylinders- I've often said the walls are so thick on those you could touch off a grenade inside them and they won't distort!

In fact, I would like to propose a new school of thought (and why I personally prefer to turn stock, ACVW engines into mini-strokers instead of balls-to-the-wall, 12-second time bombs): I believe the goal when building an engine should be to make it as long-lasting and efficient as possible, and this applies to high-performance engines, as well. And I believe there is an ideal ratio between the piston size, crank stroke and rod length that should be used to achieve this goal. Going outside of this ratio for the sake of increased displacement and/or ease of installation might increase the power output and be easier to put in the car, but you will most likely sacrifice some durability and efficiency in the process, and this just seems like a form of blasphemy to me.

So how do you get more power out of an engine without screwing up this ideal ratio? You either make it spin faster (which kind of goes against the whole ethos of longevity), or you increase the displacement by increasing the number of pistons; not by increasing the size of the ones you already have, or by increasing the distance they have to travel inside the cylinder.

By this school of thought, if you want a well-designed ACVW engine in the back of your ACVW, build a mini-stroker. And if you want a well-designed, powerful engine in the back of your ACVW, stick a six-cylinder Subi in there (just be aware that there is a special level of Hell reserved for people who do this!). Maybe go with an old 911 engine instead. It won't be cheap, but at least it'll stay German that way (and you won't burn in hell, which is also good).

Fri Jan 31, 2020 3:28 pm

You ask for our opinions on a general idea, not a answer to a specific question. You are allowed to build whatever you want and are not required to follow our advise.

Building a mini stroker with parts you already have is a different perspective then building it with new parts and not getting the most cost effective results. A 1776cc will run circles around a 1700-1800 "Mini Stroker"

Sat Feb 01, 2020 8:53 am

"Mini-stroker" refers to the crank. you can still use 92 or 94mm pistons with a 74 or 76mm crankshaft, it's not "small".

Sat Feb 01, 2020 5:27 pm

I recently just completed and sold a 1800 mini stroker (88x74) with ported 40 x35.5 valve heads, 110 cam, 1.25 rockers, and dual 40mm HPMX carbs. That engine pulls awesome, idles with a slight lope and is very fun for a daily driven street car. It's not a race car engine, but wasn't built to be. It was built because most of the parts are what was lying on the shelf at the time but I would absolutely do another.