Trenching Cases

[doorslammer]

hey guys

now im sure im going to get alot of take it to the pros or whatever.
ive trenched single cylinder vertical split cases, obviously pretty straight forward.

anyway, ive toasted the crank in my blaster and recently picked up a cheap 5mm stroker crank and wouldnt mind doing the case work myself. my question is how is it done? i have access to the machine side but only really deal with automotive. ive come up with a few ideas but would love to know how the guys doing them day in day out get them done.
obviously id understand if no one wants to share their secrets, but ive always found the x to be very helpful.

how deep does the cases need to be cut and how wide, afaik 5mm wont require epoxy?
my plan is to trench them, some light port work and bolt up my freeride ported cylinder, and cut a set of domes to suit.

open to any and all advice. sending cases from one side of aus to the other and back again becomes expensive... thats my reasoning behind wanting to do it myself

cheers

 

[Harbor]

Here are a few pics of mine, its an 8mm, i got more than i paid for by using an astute engine builder because he discovered something during assembly clearance checks. i prooly would have missed it. Here are few pics of the fly cutting for you. Can you see what he discovered? He saved my asz really. Kudoes to Brain @ Thrust Innovations

 

[wanderer1]

Have you tried putting the crank in the cases and checked for clearance issues? 5mm should drop right in without any case issue.

 

[doorslammer]

I have not yet. The cases are still in the blaster. Most of what I've read has said trenching will be necessary. Obviously things will become a lot clearer with parts I'm my hand. If 5mm will drop in without work id be stoked. I'll find out in a couple of weeks when I'm back home. I suppose there's only so much reading I can do


Harbor, is that crank cracked/split?




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[OCD Solutions]

Can you see what he discovered?

Some surface imperfections, can't tell if it's pitting or corrosion. Also looks like one of the connecting rod bearing shims is peened over or is that discoloration due to friction? Hard to tell from that angle.

 

[Harbor]

Kudoes to you both, OCD and Doorslammer for having a look at what the issue might be.

When i first saw it i couldnt see it either so dont feel bad, Have another look @ this photo

 

[JetManiac]

Crank out of phase?

 

[OCD Solutions]

The only other two things I see but just thought it was the angle of the picture. The two webs on the closest journal appear to be off slightly and there is something odd about how the bearing is sitting in the case.

 

[Harbor]

OCD I know it's hard to see, I couldn't see it either. Jetmaniac has it correct, the crank is out of phase by like 1 1/2 inches. I got screwed the seller said it was good and ready to go, I almost installed it like that, could you image the vibration I would of got and how long I would chased my tail for trying to figure it out.
The front cylinders rod pin is half below and half above the case parting line, the rear rod pin is completely above the case parting line by like 1.5 inches or more.

 

[OCD Solutions]

Yup, obvious once you say it.

 

[McDog]

Or you could sell your unmolested cases and buy some already epoxied, ported, and trenched by Paul Lehr for about the same price from pabloescobar.

 

[doorslammer]

jetmaniac, probably put more of these things together then i have hours on skis...
very obvious now! surprised if you would have ever had it running well enough to feel the vibes with timing?
true mcdog, but theres so much ocean between us and now that my blaster doesnt run i cant just swing by and pick em up haha. ive contemplated it but...
what sort of min clearance should there be between the b/e of the rod and cases?

 

[Big Kahuna]

Honestly, I cannot tell, the webs look 180 degrees to me. You cannot take measurements with pictures when the picture is taken at an oblique angle.