Type lV Main Bearings Are Back

[Clatter]

i will measure the on the cmm machine

WhooHoo!!!

THIS is what needed said here.

Don't let us down, Daddy-O!

[schantzmd]

Note:

I Picked up a set of STD Silverline main bearings today and compared them to a set of STD KS main bearings that I had on the shelf.
The Silverline set measured out to within 0.02mm of the KS set for internal, external, and thrust dimensions. Bearing #3 (The 2 piece shell) was not checked against the KS set. For the bearings checked a standard deviation of ~0.01mm was found over a 12 point measurement along the bearing shells (basically 1 measurement was taken every 30 degrees to check for eccentricity).
I'm still going to check them out once clamped into the engine case, and I'll have to see how they hold up with use (only time will tell on that one), but as of now the set I have looks pretty decent. The only issue that must be noted is that on average the Silverline set did appear to have an average inner diameter of approximately 0.015mm more than the KS set.
I'm also planning on weighing the set to verify that they are comparable in weight to steel backed factory sets. If I get that done in the near future I may post the results.

At least the good news is that we have some STD bearings available again for less than $200!

[Wally]

I'm still going to check them out once clamped into the engine case,

If you do ^^ that with the split center mains, that will be the most important check imo as its likely thats where the biggest differences are if there are any, which would surprise me if the others spec out 'ok'.

The only issue that must be noted is that on average the Silverline set did appear to have an average inner diameter of approximately 0.015mm more than the KS set.

Then they will work well on a chinese crank as they are usually that much undersized

[farmer]

Heeh ! Yes that´ll require some fat oil and a good pump.

I havent had the chance to measure type 4 bearings. But I did get a couple of sets type 1´s about 2 weeks ago (My dealer sent them without telling me )

I installed those in a new case that was checked before the bearings was installed. These 2 sets both measured 0,03/ 0,04 mm. too large on the center and flywheel bearing. They are steel backed on the center main though. So if this is the future, we will have to check the case specs with bearings before we determine what tolerances the crank should be ground to.
T

[Wally]

...
So if this is the future, we will have to check the case specs with bearings before we determine what tolerances the crank should be ground to.
T

I agree. So with a 'to be align bored' case, buy the bearings first, measure, only then bore according to outer diameter of bearings...
With a 'good' case, you should align bore just that much as the bearings are larger then spec. Would this little "align"boring (0,03-0,04mm) be possible at all you think Torben?

[farmer]

Without being a tool maker, I do have some insight in what can be done. On a type 4 case I do not expect it to be a problem, other than things get twice as time consuming due to double measurement. It also requires even more accuracy to the person that handles the tools.

For the type 1 its a little different because of the extend of the pounding on the case. theoreticly it should´nt be a problem. IRL it may mean that you will have to jump to the next oversize to get a good surface.

Eventhough I sincerly hope that Mahle will start up again, I am affraid that it is whishfull thinking. I think the best bet is to "work with" Silverline and try and persuade them to make the bearings the way we want them. (As stock VW was) Otherwise we will see a radical decrease in rebuilt aircooled engines over the next 2-3 years. Because it simply gets too expensive compared to a transplant of a subie or wbx.
T

[doc]

Here in the States, one of the big reasons vws stay popular and active is because, like Mustangs, camaros and corvettes, almost all the parts are readily available. AND they're relatively inexpensive! Not so for the v8 muscle car boys or the rare car crowd. Big bucks to buy the parts often. Now I'm not saying all parts are equal or even worthy, but for vw at least you don't have to fabricate it from scratch.

If it becomes impossible or crazy expensive to rebuild a motor, it's a big problem. I appeciate you guys keeping up with this even though it is ominous news. Sure hope it works out. I got a T4 case and heads stashed for a future build. Like to think it's not a boat anchor.

doc

[Clatter]

Let's not get too sentimental on the old bearings...
They were not exact sizes, either.
In fact, the days of getting a line bore to the stock specs have been gone for a long time.
ANY good shop will want you to bring in the bearings so the case can be cut for the correct fit (crush) to the bearings.
And, good shops will also have the crank ground to fit the bearings, too.
The case and crank can and should be adjusted to the size if the bearings, which is fixed.

Now, the real trouble starts when there is variation between bearings in the same set.
THAT is when you are hosed...

So, has anybody measured the round bearings to see if they are the same?
Another _very_ important measurement will be the ID of the split center main, compared to the other round bearings, once installed in a case and torqued up.
Variation of more than a thou or two, and we are all going to be finding another hobby - hoarding bearings!

[farmer]

Clatter, read what I wrote further up. Half the answers are there.

I do agree that much has to be measured anyway. What I´m saying is, that if "this" is the future, decent home builds will soon be obsolete, because the average Joe does not have and perhaps doesnt even have acces to the tools needed to do these measurements.

Kolbenschmidt varied too yes. But I have never seen any that varied more than 0,012 mm.
T

[Clatter]

These 2 sets both measured 0,03/ 0,04 mm. too large on the center and flywheel bearing

Does this mean that the other large bearing was in spec?
OD or ID?

It would be nice if the OD was the only significant variation.
Most shops use line boring equipment with infinitely adjustable cutters.
Having cranks turned to a new spec poses more of a problem (at least in my experience).
Must crank grinding shops around here tend to be pretty ham-fisted using their mics.

Also hoping the sets have variation that put them all off in the same direction, in a similar amount.
Said another way, high precision, low accuracy...

If they are all the same as each other, being all too big, or small, the same amount, that is workable.
If bearings from the same box are measuring different ID and OD numbers, then we are well and truly hosed.

And, for us 'Murricuns..
.012mm = .00047
.030mm = .00118
.040mm = .00157

[CobraJet]

It's been quite awhile since we had any updates on this thread.

How are the new bearings working out? Are they any good?

[christo]

Good day to all here, So where are these Type 4 main bearings ?
It seems No one will step up and say I have them and compared them to KS or Mahle

So, Step up to the plate Moderator "Type 4 Unleashed" and let us know if Standard/standard main bearings are available.
or 10/10 brgns.

[dstar5000]

VW dealers have re-packaged bearings from Brazil now.
About 50Euros a set....($75)

Don

[Piledriver]

VW dealers have re-packaged bearings from Brazil now.
About 50Euros a set....($75)

Don

Repackaged what? (brand)

[dstar5000]

Brazilian KS's, repackaged as German KS's.

Best available.

Sent 5 sets to Ozzie-land recently....


Don