Fixing cranks; dowel pins loose?? Holes un-drilled and re-drill

[modok]

Crank dowel jobs are a real challenge.
How do you make 8 pins line up perfectly at the same time, and fit perfectly straight in their perfectly fit holes with just the right press-fit?
You lie to yourself. That's as close as you will ever come. perfection is impossible
But I tried real hard this time and I took some pictures. Probably not enough pictures, but anyway it worked well enough I don't need to destroy the evidence, rather can share it.



Best christmas gift ever, my brother got me this fancy welding helmet.
Two LARGE parallel bars hang off the back of the table and there is my precision crank clamp-er, which is bored to 2.170" Shims are used to fit different sizes.

I welded up the holes, and faced the back of the crank flat again.

Put the flywheel on, check that it's straight, then attempt to ruin multiple drills and reamers boring into the welds. Wishing for a smooth hole with .001 press and praying they don't go oversize.
This device here lets you see how tapered ovaly and rough your holes are, which is depressing. it was a lot easier not knowing.

Success

[/img]

[esde]

VERY NICE.
Thanks for sharing. And nice helmet, the Speedglas are my favorite masks.

What mangled crank was that?
_________________
modok wrote:
Bent cranks are silent but gather no moss. I mean, ah, something like that.

[modok]

It's the one you think it is.
Porsche journal, Okrasa

Whatever alloy these are, weld there will be HARD spots. like a-2 steel or something.
old scat crank, chinese crank, were far easier.
I haven't yet tried fixing the one you traded me. I probably will, since I have it all setup. CRANK MODE

[esde]

Glad that you were able to fix it for him. I thought it might be the okrasa, the way they are finished is not like anything made now. And, very interesting to see the crank holding arrangement. I've been pondering the same thing, but have no parallels stout enough, yet sound like another excuse to buy tools..

I'm curious, since you've done a few of these repairs, what have you done / figured out along the way thats made the job easier?

SD
_________________
modok wrote:
Bent cranks are silent but gather no moss. I mean, ah, something like that.

[LOWE TECH]

FGood post! I’m a Speedglass fan but I’’m missing the custom paint. Merry CHRISTmas! All these little details go unnoticed unless you’ve tried ‘em yourself. Try saving a hole by welding it shut or lay out multiple holes with a tight tolerance, diametric or X-Y, be honest. Just more small details that add up to ones work.

[nsracing]

I am just curious what the runout is after the flywheel was mounted?
Mount the package on a rollers and find out.

What did you do to cleanup the welds and establish the original flat for the flywheel to sit on?

[ps2375]

I'm getting a fizzy feeling all over my body!!

[Dauz]

glen, what size are those dowels? Have you ever used 8mm?

[anthracitedub]

Very nice job man. A lot better than I did at age 17 with a hand drill on an assembled engine.😁

[veeweeman]

Modok, nice work. ..and that jig you made seems to work for you. ..I thought they made oversized pins to solve the oval-shaped hole problem? ...wouldn't it be easier to just re-drill all the holes for bigger pins?

VeeWeeman

[chrisflstf]

What reamers did you use?

[jpaull]

Nice job! Looks like you have lots of other vw goodies layen around there, cool shop!
_________________
[email protected] MPH 1/4 Mile & 8.1 @ 83.7MPH in 1/8 Mile with Mild Type 1 VW Mag Case 2234cc commuter engine in stock weight bug w/only .491 total lift(CB2292 Cam), 42x37 heads, 48idf's, Street tires, Belt on, Mufflers, Pump gas, video of the run here: https://youtu.be/M3SPqMOKAOg

Transmission by MCMScott:
Rhino case, Klinkenberg 4.12, Superdiff, 002 mainshaft with 091 first idler. Weddle 1.48 Third & 1.14 Fourth.

[Floating VW]

Holy smoked nuts! If there's ever a cylinder head shortage in the world, now I know who to blame.
_________________
"It's time you started treating people as individuals, rather than mathematically predictable members of an aggregate set, regardless of how well that works."

[[email protected]]

How much material did you end up taking off the end of the crank to make it flat?

I have at least 100 cranks that I need to do this to. Many of them are perfect std/std too....
_________________
Please "LIKE" us on facebook to see what we are working on.

https://www.facebook.com/mofoco?ref=ts&fref=ts

www.mofoco.com

Cylinder Head Reference Sheet

[Ebel]

I would think the labor involved would make it too costly to save stock cranks.

[modok]

[modok]

[modok]

[Brian_e]

Awesome work!!

Have you perfected the broken off flush pin removal yet?

Modok's FUBAR'ed crank repair service.

Brian

[esde]