TheSamba.com :: View topic - Stroker 101: The beginners guide to stroked ACVW engines.

Thu Oct 23, 2014 2:56 pm

What's amazing to me is how people overthink and over engineer a simple 130-150 HP engine for their street VW. For 90% of the people reading this thread a China crank with VW or Chevy journals will be plenty strong enough for their engine.

Thu Oct 23, 2014 4:59 pm

Dan Ruddock wrote:

WHOA!! That's awesome. WOW

Thu Oct 23, 2014 5:07 pm

It's pitiful. People think you need a $1500 crank for a 120hp engine. Preposterous.

Most people have no thinking skills. While it is technically correct that a Chevy/Buick journal crank makes for a weaker crank, it won't have any issues in anything under 500hp, probably a lot more than that.

So why the Keyboard Ninja's argue about it is comical to watch.

vwracerdave wrote: What's amazing to me is how people overthink and over engineer a simple 130-150 HP engine for their street VW. For 90% of the people reading this thread a China crank with VW or Chevy journals will be plenty strong enough for their engine.

Thu Oct 23, 2014 5:24 pm

The definition of a masterpiece is a PIECE that proves you are a master of your craft. Welding crankshafts is a craft. This proves the creator is a master. Usually, the guy who finances it is out of his mind. I don't find this unusual :D

I asked bob about drilling the rod throws. he said yeah we done that but it's not really worth it. Practical advice..........masterpieces aren't usually worth it, or are they??? Worth it to prove a point

Thu Oct 23, 2014 6:03 pm

John the crank cost me $550 and I should have more like 160hp.

With the high cost of engine cases today the money is well spent if I can get longer case life with this crank.

I would rather have a berg crank which is better but that would be hard on the budget

Thu Oct 23, 2014 6:11 pm

I wasn't talking about your crank Dan, I was replying to Dave. That's why I quoted him in my response. If I was replying to you I would have quoted you instead.

Dan Ruddock wrote: John the crank cost me $550 and I should have more like 160hp.

With the high cost of engine cases today the money is well spent if I can get longer case life with this crank.

I would rather have a berg crank which is better but that would be hard on the budget

Thu Oct 23, 2014 8:00 pm

Don't cranks over 76mm usually cost more?

Most the websites I looked at had the stock, 74 and 76 cranks close in price and then the 78+ strokes cost more. That's another reason I went with the 76 stroke.

I know where he got the stroker cranks all cost the same comment from, but it's not true.....just look on the website you got that info from in their pricing section.

good write up....I like all the responces and stuff I am learning.

Thanks
TIm

Thu Oct 23, 2014 9:59 pm

Most 74-76 cranks are a cheaper and weaker 4140 material while 78 & larger are made of a more stronger 4340 material causing them to be $20-$50 more in price.

Fri Oct 24, 2014 5:21 am

Thanks for your efforts and research, Mal.

In the early '90's I also became interested to advance beyond a mild stock-stroke engine and utilize a stroker crank. By attending several VW meets here in the NY tri-state area, I soon learned that Gene Berg's parts were top-notch. $$ yes at the time, though there were almost no "cheap" versions then. In preparation of buying parts either new or finding used deals at swapmeets, I purchased many of Berg's (copyrighted) technical articles including this one for stroker cranks- http://www.geneberg.com/product_info.php?cPath=432_2927&products_id=1315

Reading the material while inspecting a stock-crank shortblock on my workbench enabled me to visualize all of the extra checking and work needed to the case and other components to fit a stroker crank. Mal, I encourage you to buy this tech article and others of his. Yes, it's over 20 years old unless the company has updated some material, but it's a readable ("old-fashioned") paper document and certainly still applies to the cranks now readily available. If you find it helpful like it was for me starting out in the engine hobby, then please include it with your "general build" list on your first page.

Fri Oct 24, 2014 8:25 am

Dan Ruddock wrote: mark tucker wrote: "flawed crank design" so lets weld some hunks non german steel to it and it's good to go,nolonger flawed.!!!....Ill stick with the china stuff,Im not sure there is any german left in my engine at all :shock: although your crank looks to be done right with the throws drilled and not the counter weights. like I said befor I have one of those and it's not right,it's the 3rd of 3 that I have had that are not/were not right.2 were fixed,the 3rd is on my shelf.I just dont see any addvantage at all just trubbles,worries&unusable stock taking up room on the shelf.

One of the advantages of weld on C/W is you don't have to drill threw the weights. Yes this is a attempt to make the VW engine less flawed. To fix it right the engine needs to have five main brgs and that is not in my budget :shock: nor was it in VW's budget. When I tore down my berg crank engine the center main looked perfect, also a attempt at less flawed. But I made the mistake of selling it many years ago :(

Dan when I split my 2028 to reseal the case the bearings had about 60000 miles on them,now close to 100000, miles on the same bearings,with a cast 78.8 scat crank, yes cast. so where is the issue with the design on the amount of bearings? I cleaned and reseal the case,no parts changed at all.just sealer(518).
And yes if your crank is done right and straight those lightning holes will help it. If I still had a balancer I would probably drill my china cranks and also add tungsten to the counterweights to farther offset the weight of heavy throws/rods. but I dont and they work just fine as they are when properly balanced.
anybody notice how the alot smaller honda journol crank dosent have a breaking issue do the the non overlap issue that some think is an issue???

Fri Oct 24, 2014 9:36 am

Mark, the Honda crank is a completely different animal and to compare it to a horizontally opposed vw is not relevant.

A inline four has very thick cheeks (3/4" on my Honda B18b crank) between every journal connection, a VW does not. Yes I have built some honda engines. A in line four has a main between every rod journal, a VW does not. Every journal connection has some overlap but not a lot on my 89mm B18b crank, a VW does not. There is no need for large rod journals on a inline four because of all this.

The attempt by the VW industry to market a 78mm 1.80" rabbit rod drop in with no case clearing was a complete failure. The case was pounded in short order.

You need to upgrade you engine study skills. Some call this over thinking things.

Dan

Fri Oct 24, 2014 4:51 pm

The honda has wider cheeks, and much stronger block.

Even so they have a model with extra small diameter bearings to improve economy, and if you put a turbo on THAT one, there is trouble. :shock:

Sat Oct 25, 2014 2:49 pm

and there are plenty of that size with very little cheeks out there in many other engines drag,nascar. so ...how much material is in your cheeks with the offset and the holes.......a little closer to a full circle may of helped with that. I dont need to do much more research,Ive been in plenty of motors. but the honda does use better steel.......as I recall. but I dont think there is an issue in the vw motor unless it is caused by something else then blamed on that.

Sat Oct 25, 2014 5:07 pm

What if we take a subaru and remove the extra main bearings, the special "flex plate flywheel", and the harmonic dampener. hell, just remove any ONE of those things and it'll be trouble.
The engine design lets them use a weak crank and it works fine. Our engine needs a strong crank because it., well, because they didn't bother with any of that complicated design stuff :lol:

Sat Oct 25, 2014 6:50 pm

Well put Glen.

You have to also remember that every mm that you stroke it from the stock 69mm weakens the crank. That is why I put those horse shoe gusset weights on my crank to try to recover some of that strength.

Don't blame the engine case, the problem is the crank.

I have overhauled enough mag case 911 engines and have seen none of the case pounding problem with that engine because of the very ridged crank and the 120 degree layout.

Dan

Sat Oct 25, 2014 6:56 pm

I've never seen any work done to prove what the problem or problems actually are. They may not be as unsolvable as they seem.

IMO, a lightened flywheel does for us what the flexplate flywheel does for the subaru. Can't prove it tho, only an educated guess.

Sat Oct 25, 2014 7:26 pm

The Subaru crank is stronger than you might think. Every journal has an overlapping connection just like the 911 crank. That is why the cheeks are thin because they don't need to be thick.

The thick cheek part of a vw crank is where I believe a lot of the bending is happening. I asked Jose if he could gusset the thick vw cheek like Bob does and he said no.

The problem with the VW is most engines with some miles don't pass the finger nail test on the #2 main.

Some might interpret me as a vw basher but I am not, there is a lot I love about the type one VW engine and the car. Like rear wheel drive and light weight.

Dan

Sat Oct 25, 2014 7:41 pm

Dan Ruddock wrote: I asked Jose if he could gusset the thick vw cheek like Bob does and he said no.

Dan

Huh, I wonder why. Your probably better off. With those done the crank is hard to handle, it just rolls off the table, gotta put wheel chocks under there to work on it.

Sat Oct 25, 2014 7:48 pm

modok wrote: Dan Ruddock wrote: I asked Jose if he could gusset the thick vw cheek like Bob does and he said no.

Dan

Huh, I wonder why. Your probably better off. With those done the crank is hard to handle, it just rolls off the table, gotta put wheel chocks under there to work on it.

I wanted him to make it look the way a waserboxer crank looks and he said I can just do a full circle. I don't want that because it adds weight to the wrong end.

Dan

Sun Oct 26, 2014 6:54 am

Subaru....

Dale