Sussing engine parts viability.

[ruckman101]

So I have a set of 87 mm cylinder/piston set shy one cylinder. If I can pick up a new cylinder, anyone see any big issues with running them with single port heads and a H30/31 carburetor?

Looks like I have a case that's been align bored .040 over. And a crankshaft that's been polished and is ready to go, but I don't understand the tag the machine shop left on it. It says: Crank is .010/.010 New grind .020/.020.

Does that mean the crankshaft has been ground twice and is now .020 under the original dimension?

neal

[ruckman101]

Anyone know offhand how to tell if this cylinder set is cast or forged?

neal

[Amskeptic]

Anyone know offhand how to tell if this cylinder set is cast or forged?

neal

Neal, honestly . . . the only way you get to have answers that you can *live by* is to take your parts-in-question, and your questions, to a competent local machinist where you can both inspect in real time.
I could tell you that cast pistons feel lighter and have casting marks, but forged pistons have forging marks, too, and all iron cylinders are cast.

My questions with what is this, aftermarket? piston are:
Was it properly cam ground at the skirts? There are steel inserts in factory pistons that help them contract oblong to keep them quiet during cold operation then expand to a round shape when they get warm.
Is the crown to wrist pin distance deadnuts accurate with the other pistons?

You may, as mentioned in the Bentley and every other book on Volkswagen engines, mix-and-match pistons and cylinders to your heart's content, BUT, there is a critical step before you actually install a different piston/cylinder into the engine . . .
. . . what is that step?
Colin
(hint: balance)

[ruckman101]

Mahles. But for the life of me googling the part numbers on the box don't tell me. Places that sell mention forged and cast, with a big price difference, but not the part number for confirmation. Most annoying. Mahle K70210.

Yes, I'm big on balance. Need to get a scale. Wasn't planning on slapping one new piston on there. Haven't gotten that far yet. Going with a different case known to be already align bored, and the crankshaft that came with the "Engine Kit" I picked up from Bookwus that also is a known entity, both it and the case having made their trips to the machine shop already. The cylinder/piston set was a "get it outta my garage" gift from snap, essentially new but for a few hundred miles, and missing one cylinder.

The crank and cam from the blown engine actually still look and feel pretty decent, surprisingly, but for cost and expediency, am leaning to the "Engine Kit" box. It's got everything there for an entire short block but heads and cylinder/pistons. Two cams, one is a zero, the other -2. The connecting rods have me concerned though, as they have their old bearings on them still, which to me would suggest they haven't been to the machine shop. So that's my task tomorrow, seeing if I can determine on my own how close to spec they might be. Not too encouraged by the lifters, either. They seem a bit flat, but need a closer look.

As for heads, I have the pair of single ports that were on Ramona's engine that lost a piston, and a set on the limping engine I pulled from our Ghia, Gretchen. And three or four used dual port heads, again, of unknown integrity. I think I would rather run another single port engine in Bertha. Then there's the carburetor, oi, how quickly my head begins to spin. I think the H30/31 was doing fine. I did rebuild it before putting it to task on Ramona's engine that recently met it's demise. It was the healthiest looking thing I had in my collection at the time.


One step at a time,
neal

[hambone]

I have a set of used Mahles old school but clean I got from Sluggo. They probably need new rings, not sure. Trade me somethin'.

[ruckman101]

More confusion. It seems to me that I recall that the smaller diameter head studs were preferred over the larger. This case has 9 mm thick studs, vs the ones on the old case that are just over 7 mm. And then there's the camshaft. The purtiest one has a much deeper dish to it for the oil pump tang. Are there other differences? Is it a matter of matching the oil pump to it? The lumps look the same.


neal

[ruckman101]

Old school Mahle's? Interested, yep.


neal

[Amskeptic]

Old school Mahle's? Interested, yep.


neal

Neal, I forget to mention, your bus prefers 85.5s.
Colin
(does too)

[ruckman101]

I have made no rash decisions. Too many questions.

Connecting rods need to be rebushed. Again, dipping into my "engine kit" I picked up a few years back, I slid a wrist pin into one of the connecting rods and it rocked. They haven't been rebushed (what a fun word, rebushed).

And caressing, measuring, fooling with the crankshaft, with a tag from a machine shop still attached, I feel some irregularity on one of the main bearing surfaces. The small bearing immediately behind the pulley. Is that main bearing one or four.

The lifters seem good. I suspect they are reground, as they have a shiny outer ring and are dark through the center.

So in the interest of organization, and purging, I tore down Gretchen Ghia's engine that had been running poorly, and will drag out the carcass of Bertha's original engine, and see what the heck I have on hand.

And apply measuring devices.

Then there are heads. I have like three sets of used DP heads, another set with big valves, machined out for bigger pistons, too, I suspect, and two sets of single port heads, from Gretchen's old motor, and from Ramona's recently demised engine.

And my machine shop of habit is no more.

And yes, not yet, but I will be measuring the bore of the case I'm at this point has also come back from the machine shop and is just waiting to be put to service.

A lot of parts washing in my future.


neal

[ruckman101]

Took the power washer to the five cases I have, and every bit of tin I could scare up quick, with the exception of fan shrouds. Knocked the worst of everything off. Tomorrow, clean up the shop a bit bagging parts, then start measuring cases.

Case that came with the Betty Baja, not much hope for it. Bertha's original case, not much hope for it. Gretchen Ghia's original case, hopeful. Ramona's case, that just lost a cylinder, hopeful. And the Bookwus case, most likely the one.

Still taking stock.


neal

[Amskeptic]

Case that came with the Betty Baja, not much hope for it.
Bertha's original case, not much hope for it.
Gretchen Ghia's original case, hopeful.
Ramona's case, that just lost a cylinder, hopeful.
Bookwus case, most likely the one.

How are you determining viability on the cases?

What is the Bookwus case history?
Colin

[ruckman101]

Inspect for cracks, measuring the bore of the bearings for out of round, previous align bores. Bookwus case came from an "engine kit" that he had put together that no one at the Woodburn meet had purchased that I picked up. Pretty much everything but heads and piston/cylinders. The bores are smooth at a glance and it is written on top, .040, which leads me to suspect it has been align bored, but after a waffly #4 bearing surface on the crankshaft that still had a machine shop tag, I am assuming nothing. Not sure how to check for alignment of the bores to each other.


neal

[Amskeptic]

Inspect for cracks, measuring the bore of the bearings for out of round, previous align bores. Bookwus case came from an "engine kit" that he had put together that no one at the Woodburn meet had purchased that I picked up. Pretty much everything but heads and piston/cylinders. The bores are smooth at a glance and it is written on top, .040, which leads me to suspect it has been align bored, but after a waffly #4 bearing surface on the crankshaft that still had a machine shop tag, I am assuming nothing. Not sure how to check for alignment of the bores to each other.


neal

#1 Main bearing is the flywheel side (I can't BELIEVE you asked that) that takes all the thrust loads from stepping on the clutch.
You want to check, with a new bearing in hand, the fit of the #1 main bearing in its saddle. If you have any movement in the thrust direction, you will need special oversize bearings for the thrust direction as well as the .040" oversize saddle and what ever the crankshaft journal has in store for you for a total of THREE numbers you have to keep straight for that one bearing.
ColinItISFun

[ruckman101]

Interesting. Ramona and Gretchen's cases seem about the same. 65.50 roughly. The Baja case near the same, but pounded out a bit oval. The Bookwus case, consistently 66.00 more or less. And Bertha's 66.70. Stock new is 65.00. So I would assume the first align bore would take it to 65.02, second to 65.04, third 65.06 and so on. Not sure if Bertha's case was on it's third or fourth align bore. Guessing fourth.

So my assumption was that a case marked as being align bored .040 over would measure at 65.04, not 66.00. Am I missing something?

Looks like I'll be going to Mattney Racing, recommended by Avery's, for machine work, I think they are the folks making those delicious new type 1 cases that they are exceedingly proud of. My thought is that perhaps they are doing a smaller volume, and would devote more attention to the tasks.


neal

[bajaman72]

Standard = 65mm
1st = 65.5
2nd = 66
3rd = 66.5
4th = 67

THRUST

Standard = 22mm
1st = 21mm
2nd = 20mm

Hope this helps.