Engine Yoke

Superman · 03-02-2002, 04:42 PM

I have used a common, adjustable engine stand and yoke made to fit almost any engine, and it has worked fine until now. For my next trick, I am going to split the engine case and replace a few bearing shells, and I am feeling uncomfortable about the adjustable yoke.

I have borrowed a yoke from my 914 friend which may work, but it worries me a little also. The "real" yoke to use is a bucket-shaped thing with plenty of room for the flywheel etc. The 914 yoke is this way. But the "real" yoke also has a curved piece that fully engages the curved part of the case half, right where the tranny touches it. The presence of this curved piece, at the point equidistant from the two engagement studs, provides great support for the case half. The yoke I have borrowed does not have this curved part. The long engagement studs sticking out of the case half go through the yoke with only about 2" of yoke pressing against the case seam. Worse, most of that 2" extends upward (while the case half is laying down, ready to accept the crank, etc), rather than downward where it would provide the best support.

So, with virtually nothing supporting the case between and below the big attachment studs (while the case is laying sideways), I am afraid all this pressure will be too much for the case at the point where the studs go in.

This is difficult to explain, so I hope someone out there knows what I am nervous about.

Bill Verburg · Bill Verburg's Garage

You can use an adjustable strut to support the end, as pictured

Jim Sims · 03-02-2002, 05:16 PM

Superman, Yes the generic engine stands do not provide adequate support at this assembly step. As you point out, the two studs supporting the engine are in a horizontal plane when the crank is installed and do not have much leverage or mechanical advantage. Our solution was to use a prop attached to the other end of the case half; the prop was a steel tube between the base of the engine stand and a couple of the console mounting studs on the case half. The tube had a little U-shaped botton piece that slipped over the center member of the engine stand and a plate at the top with the console stud hole pattern drilled in it. Perhaps you can rig up a support like this.

Jim

john walker's workshop · 03-02-2002, 06:37 PM

years ago i had a 2.7 on a stand and the helicoil for the top stud pulled out, which promptly broke the bottom stud, and dented the muffler as it hit the ground. and scared the crap out of me, just missing my foot. aluminum cases don't have helicoils there, but there's still lots of leverage on the studs. somewhere i have an extra yoke, if i can remember who i lent it to, and you may borrow it if it shows up. you know how that "lending" stuff goes. if you don't write it down, the bastards never bring it back.

yelcab1 · 03-02-2002, 06:56 PM

Superman

Don't use the generic one, the Porsche one relies on the contact between the case and the entire yolk to support the weight.

Give me your address, I will send you my engine yolk. Send it back when you are done.

Mitchell

Early_S_Man · 03-02-2002, 07:05 PM

Super Jim,

I don't think the yoke is at all critical ... if you fabricate a support for the far end of the case! And, the only adjustment that would be needed on a 2 x 6 would easily be handled by a sabre saw during the mating and securing stage ... the biggest 'variable' factor will be the style of the stand, whether 3 or 4 caster design! A few pieces of scrap 2" x 2" angle iron and a few bolts should facilitate securing the 2 x 6 to both stand and 'far' end of the engine. A bit of extra work, but no serious worries!

orbmedia · 03-02-2002, 09:36 PM

Oh yea, I know how that lending thing goes. My yoke is gone because of that.

Superman · 03-02-2002, 09:40 PM

Thanks, guys. I appreciate the offers, Mitchell and John. I've got an autocross date on March 23rd, so I think I'll just fabricate a temporary support for the far end of the engine. With luck the case will only be apart a day, and then I can go back to the generic yoke. I am thankful for the input, since I just was not sure. It sounds like I needed this advice. Bill, I think you might have gotten just a bit lucky.

J P Stein · 03-02-2002, 09:48 PM

I'd borrow you mine, but it's already lent......back east somewhere.
It gets around more than I do

Bill Verburg · Bill Verburg's Garage

?Lucky?

Leland Pate · 03-03-2002, 03:46 AM

I assembled the case on a work bench. Thus, I didn't have to worry about my modified stand supporting the weight of the bottom end on its side.

After the case was buttoned up, I simply attached the yoke to the studs on the bench and had a friend help me pick it up and put it back on the stand.