stroker drawbacks

Kubelmann · Post by **Kubelmann** » Thu Jan 23, 2003 9:15 pm

As I build my new motor, I am thinking about going for a stroker with an unmilled case. Mahle pistons and jugs and all the right new parts. I was going for a 94 piston for a 1904 or 2007. Now I am considering the stroker action. Share any thoughts about the drawbacks of a stroker set up.
Thanks, K-mann

Bob Ingman · Post by **Bob Ingman** » Fri Jan 24, 2003 7:16 am

I like the stroker engine for several reasons.
As Jake will be quick to point out a stroker engine runs cooler because it draws in a lot of cool air.He recomends it in a bus engine for that reason.
Long stroke is a contributor to bottom end torque as needed in an off-road Thing. I would even go as far as to say in your case that single port heads should be strongly considered to add to this. A torque engine is just about opposite from a rev engine in concept and design.
The case and heads need not be cut.
That money goes a long way to offset the cost of the stroker crank. Counter balancing is standard in strokers so deduct the cost of a CW 69mm crank as well.
Quality piston liner kits are less expensive in the smaller sizes by using good German replacement parts. High quality big bores are also high dollar.
I`m sure there are more reasons but off the top of my head I see these listed. In short, the stroker engine is probably less costly than might appear at first glance. Good luck. Bob Ingman

[This message has been edited by Bob Ingman (edited 01-24-2003).]

Max Welton · Post by **Max Welton** » Fri Jan 24, 2003 8:27 am

OHC, Wankle and 2-stroke designs are meant to turn fast. We wind up using all sorts of things to control valve float.

Using a long stroke to increase power would seem more appropriate to our pushrod engine's design than trying to make it spin fast.

In theory at least, you could build a stump-puller on the VW design that never needs to turn above 4500 and make up for it with tall gears. You could then get away with stock valve springs, yes? And that would result in much less wear on the valve-train. Heck, the only reason left to use staight-cut gears would be for the sound.

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Max Welton http://www.vocs.net/

Advokat · Post by **Advokat** » Fri Jan 24, 2003 12:30 pm

Hey Kubelman,

I am building a 1904 right now for my Thing. As Bob mentioned, these engines are recommended quite highly for their torque. Just so you know, the 1904 is a 74mm crank w/90.5 jugs, not the 94's.

Alot of people will tell you to stroke large if you're going to do it all. Fine, but remember, with a 74mm crank, you will have little, if any, case clearancing to do (mine dropped in with no clearancing needed).

This is also true, from what I am told, with the 76mm crank. Plus, when you use these smaller stroker cranks, you can still use the standard length (stroker clearanced) rods and don't have to run the "B" pistons/jugs.

Good luck

Kubelmann · Post by **Kubelmann** » Fri Jan 24, 2003 5:35 pm

Advokat,,,

You addressed the exact issues I am considering. Yes I want to go with stroker on 1904 soa as to go with 90.5. Tell me more about your crank and rods. I know i am going with Mahle and want 90.5 Explain more about the drop in clearance. Great stuff on your last post. Keep it coming. RW

James2 · Post by **James2** » Fri Jan 24, 2003 6:44 pm

90.5 X 78 mmm with bugpatch heads and a web 218 would crawl and haul!!!!

Advokat · Post by **Advokat** » Fri Jan 24, 2003 6:57 pm

Well, I had some very reliable sources point me to DPR Machine Shop (714) 979-7441 for the crank. So, while I was at it, I purchased my stroker clearanced rods there as well as a lightened flywheel. The stroker clearanced rods are simply stock VW rods that have been ground down around the big end where the bolts protrude. You can buy something like Scat I beams, but they are quite a bit more expensive than the ones I bought. Good enough for me as I don't plan to race or to turn 10k rpm's.

The guy you want to speak with there is Jose and his prices are competetive. I think the crank ran me about $325.00 and the rods were another $60.00, or there about.

As to the case clearancing issue, I was very concerned about this and got a different answer from everyone I spoke with as to whether it would be needed or not with the 74mm crank. The answer is: It depends on your case. Some are more "meaty" than others and some slight clearncing may be needed. If it does have to be done, it will be minimal and can be accomplished with a Dremel. Just be sure you have 40 thousandths clearance as you rotate the crank through its revolution-if so, no clearancing necessary. If not, then clearance the offending areas. The majority of those that I spoke with, however, believed that with the 74mm crank, you will likely not have to clearance at all.

Hope that clears up your concerns.

Rick

[This message has been edited by Advokat (edited 01-24-2003).]

Bob Ingman · Post by **Bob Ingman** » Fri Jan 24, 2003 7:39 pm

I used a CB 76mm crank with no need to clearance the case. I did have to do a little on the rod bolts however. It was minor and easily done with a belt sander . I was able to get them within a gram of each other in weight before all went to the shop to be balanced.
Best to check with WebCam for the cam of their choice in any given situation.
Who has comment on the use of single port heads for a torque producer. How about a single Zenith to top them. Good luck. Bob Ingman

Post by **sparkmaster1** » Fri Jan 24, 2003 8:01 pm

I'm doing a 74 x 94 for a guy right now. He got a dpr 74 crank and CB unitech rods. I did the standard clearancing before I got the rods. After dropping in the crank/rods I not sure I wouldn't had to clearance at all. I think it will be a good combination. It should be running next week after I get the heads back. Tim

Kubelmann · Post by **Kubelmann** » Fri Jan 24, 2003 8:39 pm

Y'all keep sending me to a 30 yr goal:
1904 stroker, Mahle pistons and jugs, DPR 74 mm Crank, Rods etc. We have the balance, assembly, weight balance amd fine machining details more than covered etc covered. What about lifers, push rods, cam and small parts. I am compiling data here. Our crew is not new we are old and we will create a fine mill will y'allzz new school guildance. K-mann

Bob Ingman · Post by **Bob Ingman** » Fri Jan 24, 2003 9:12 pm

Kubelmann, better throw in a couple more for you. How bout you shoot for an 8.5:1CR and no larger than a 1 1/2" exhaust, smallish valves as well. We`re talkin no stall in fourth gear around the corner torque here. We`re talking Grand Junction to Denver in fourth gear .Do`nt go completely crazy on the cam either.Them big lumps effect the bottom end. That way it do`nt hurt your motor to go so slow. Praise this Traffic Jam. Good luck. Bob Ingman

Post by **Henryhoehandle** » Sat Jan 25, 2003 5:33 am

You asked for drawbacks... well for one, your case must be clearanced. Also, it will take a little more time to set up your deck height. In some cases, the camshaft itself will have to be clearanced too. Other than that, the benefits far outweigh the problems listed above. Strokers give you a lot more power, bottom end (as long as cam is not too wild), and just great performance all around.
Good luck
Eric

Post by **Henryhoehandle** » Sat Jan 25, 2003 5:34 am

By the way.. I would go ahead and mill the case and put in 94's - Eric

Bob Ingman · Post by **Bob Ingman** » Sat Jan 25, 2003 12:41 pm

Henryhoehandle, good to see you here. I`ve posted transtalk so many times on STF I can do it by heart now. Good luck. Bob Ingman

Kubelmann · Post by **Kubelmann** » Sat Jan 25, 2003 2:35 pm

The motor looks like this so far

90.5 Mahle pistons and jugs
74 mm DRR Crank and rods
8.5:1CR
Exhaust no larger than 1.5" I would love to get pipes through the stock bumper holes and will also be using heat exchangers
Zenith carbs (one or two??)
009 dist
Empi heads
Cam 110 (kind?)
oil pump - filter system?
Push rods?
push rod tubes?
lifters?

Ideas? K-mann