Biggest Crank in a Type4

[Schrauber Jan]

What is the longest stroke to fit in a Type4 case?

[bj]

this has a "depends" answer:

how big is your cam?

what journals do you want to use?

how much clearancing do you want to do?

i am running a 80mm stroke, 2.0l journals, reduced base circle cam with a .500" lift. the case and cylinders needed some clearancing.

there are others running bigger strokes here, but more work is involved.

search for type4unleased. he has built some crazy motors and is a nice guy to boot.

bj

[Schrauber Jan]

Biggest ever tried?

Want some Crazy stuff to build!!!...

[Unkl Ian]

Clearing becomes a problem with large strokes,
since the cam lobs line up with the rods.

Jake went pretty big with his 3 liters, and was working on something bigger.
Numbers will be in his old forum here.

[wrenchnride247]

86mm is about it...

[dstar5000]

111X90=3484cc is max physically.

This will require removing the oil cooler mount as well as the other various mods...

Don

[Wally]

I have seen 90mm, but could only be done with a very small rod journal, which usually weakens the crank.
With extremely good ($$) materials and light weight reciprocing weight parts (more $$), this stroke did make a certain auto-cross-buggy european champion in their class back then.
So it can be done, but the effort and costs will rise exponentially, providing you(r builder) even know how to, to begin with...

[typ4]

Hey dstar, that made my ears perk up. 111mm cyls, do tell.

Wally do you have some pics of your setup, I am doing another engine for the wifes rail and I like your HP numbers.

[Wally]

Wally do you have some pics of your setup, I am doing another engine for the wifes rail and I like your HP numbers.

?? the 90mm is not my engine if thats what your asking?

[typ4]

Wally do you have some pics of your setup, I am doing another engine for the wifes rail and I like your HP numbers.

?? the 90mm is not my engine if thats what your asking?

Nope, not what I was asking, just curious about turbo layout, injection system and such. Heads?

[Wally]

Wally do you have some pics of your setup, I am doing another engine for the wifes rail and I like your HP numbers.

?? the 90mm is not my engine if thats what your asking?

Nope, not what I was asking, just curious about turbo layout, injection system and such. Heads?

Ah, its all in here mate:

http://www.shoptalkforums.com/viewtopic ... 1&t=115287

[dstar5000]

Hey dstar, that made my ears perk up. 111mm cyls, do tell.

Wally do you have some pics of your setup, I am doing another engine for the wifes rail and I like your HP numbers.

lycoming
$$$

ebay.com, under airplane parts....


DOn

[Type 4 Unleashed]

Hey dstar, that made my ears perk up. 111mm cyls, do tell.

Wally do you have some pics of your setup, I am doing another engine for the wifes rail and I like your HP numbers.

They are 111.125mm, Lycoming Aircraft cylinders.

[Type 4 Unleashed]

I have seen 90mm, but could only be done with a very small rod journal, which usually weakens the crank.
With extremely good ($$) materials and light weight reciprocity weight parts (more $$), this stroke did make a certain auto-cross-buggy european champion in their class back then.
So it can be done, but the effort and costs will rise exponentially, providing you(r builder) even know how to, to begin with...

I know of 2 90mm cranks done by EMW from SCAT 86mm cranks, with Chevy 2.0"-50.8mm jrl's and are ran with the Cunningham rods.

A smaller jrl say a 46mm rabbit with a rods outer dia that's been reduced in proportion with the jrl will provide the much needed clearance for the #4 & #2 rods and the respective cam lobes. Even allowing for a cam to make such a stroke reach it's potential.

[Wally]

Yes indeed; and if you give that crank the proper heat treatment and make sure it lubes the rod journals well, it will probably work just fine