Need help Id'ing custom? bearings
 

Hi Everyone,

Recently purchased a 1969 Targa L 2.0 which was supposedly ready to be assembled (it's a project) with mostly just aesthetic parts missing.

Well... turns out the engine is in REALLY bad shape, looks like it threw a rod at some point in its life and someone assembled it with VW rods (bent as well) and the crank got scratched so did the case.

To make matters worse seems it was stored for some time without spark plugs so there are several cylinders which have very high corrosion. Also there is one of them that has no corrosion, but for some reason it's cracked. And there was all sorts of junk almost as if mice were living inside the engine. Terrible....

To make the story short, right now I'm looking into the main bearing / rod bearing / re grinding / deal and I have a few questions.

The shop says the Mains will go to 0.25 on the case side (undersize?) and 0.50 (oversize?) on the crank side, and the rods will go to 0.50.

Now to cut to the chase...

The measurements on the mains confuse me a little probably since they have to rebore the mains tunnel and that's something I've never done before.

I live in Costa Rica and import taxes here are terribly high so here's my question.

Are there any guides on the internet, print or whatever I can use to find bearings that will fit the size of the journals and the mains? Even if that means machining the bearings width or machining the crank a bit more or a bit less?

I've been unsuccessful in my pursuit of finding info on the internet so far. I’ve only read something about using 3.0 sized journals with Buick bearings? Nothing about the mains aside from people suggesting I fill them with solder and re bore to use STD. (sounds dangerous)

The original Porsche ones which I think are the ones I need are very very expensive and apparently rare (specially for mains).

Can you please give me some advice? You can imagine we don't have many Porsche specialist engine rebuilders here.

Thanks.

Not clear on what the machine shop wants to do, but would not let a shop that does not specialize in the Porsche engine, handle the job. You have two possible machine concerns. Does the case need machining and does the crank need machining. Depending on the damage, sometimes you can't repair. If the case is a correct number, try to keep it, but a crank you can purchase and that doens;t effect the authenticity of the car. Bob

Hi Bob, the case is matching numbers to the chassis hence why I want to keep it.

There are no Porsche specialized machine shops over here at all, though they have worked on some engines through the years.

They want to bore the tunnel where the mains go through because it open at the top, once you mate the cases they've become elliptical per say.

Then they need to re-grind the crank in both mains and rod journals.

I've seen the crank myself and it is scored so I guess that's something they have to do no way to do around it.

Oversized bearings are ungodly expensive.

Honestly surprised some machine shop hasn’t figured out how to make some other car bearing work...

That's what I was hoping! Finding some knowledge of other bearings that may work.

Most decent Porsche machine shops can remachine the main bearing saddles back to standard size (no oversize case bearings needed). It's not cheap though. The crank is a bit more involved, as Porsche cranks should be rehardened after machining. There might not be anyone local to you who can perform that. It might be easier to find a good used crankshaft and have it shipped down there.

Haven't heard of using Buick sized crankpins, but I do know that Honda rod bearings (1.85" dia.) are very common in all sorts of race engines. Obviously you'll need custom rods to match. But this is WAY more involved that just a simple crank regrind.

Again, that is a very specialized job. I am pretty sure you need a special jig to hold the case and then a special boring bar to make the cuts. As one responder commented, a complete face and bore job would allow you to use standard bearings, but that is expensive as well. By a good standard used crank. Your crank is I am sure bent, will have to be straightened and then cut. Bob

Jesus that whole shaving the case down sounds scary as hell in an (engine destroyed) kind of way. Doing that and buying a STD crankshaft sounds like a good idea though.

I talked to the machine shop and it looks like the warping is only present in one case in which some previous idiot welded the case where it threw a rod :( agh.

There are places that coat bearings with Teflon, ads some thickness. Cheap too, $100 or so.

If your crank isn’t too damaged, that might be enough...

you have two problems to fix. #1 the case is warped and the mains are oval. Over size outer diameter bearings are exponentially expensive. Generally the best way to address this is to send case to Porsche specialist were they machine material off case and then bore mains back to standard. This is specialized work that you need to have a Porsche specialist do.#2 Crank is more standard. Over size rod bearings (crank turned undersize) are not to bad. Same with mains.

Mains that are bored over on case size and turned under on crank are very very expensive.

john

Thanks for your input so best way to go would be shave the whole engine case I suppose they shave everything just a little but not as much as to cause a problem with the stroke length?

And yes those bearings I've found are super expensive!

I think .010'' at the most on each half. Stock piston to head clearance is probably .060-.08'', so not a problem. 2.7 cases would actually bend over time like a banana, so all kinds of massaging has to go on to get that to work. I repaired a terrible 2.7 case years ago for one of my cars (never for a customer) and it is still running well. Does it leak oil, yep. The 2.0 cases probably don't have the 2.7 issues as they were not subjected to the heat and additional load of the 2.7s and more material, as the cylinder holes are smaller. Proceed carefully

The machining operation is called "line boring," or "align boring," and is a pretty standard machine shop operation, except your machine shop needs to have a mill (or precision grinder) large enough to hold the case halves. Then the main bearing saddles are bored to size with a boring bar. After that the rear main seal area needs to be touched up. We're usually only talking a couple of thousandths of an inch so everything north of the crankshaft will still be in spec. Stroke length is not affected, only deck height. The stroke is product of crankshaft throws.
I see that Ollie's charges about $900 for this operation. Maybe someone down there can perform the machining operation for you.

Thanks for the info on this very helpful, I'm learning a lot the hard way.

I will ask the machine shop if they have that kind of abbilities.

0.5 on crank and 0.5 on rods is expensive but not as crazy expensive as the other ones!

I could even get myself a STD crank but I usually worry they if had stored them sideways.

I just se a new brand `king bearing` maybe you can find them in the states.

https://www.ebay.de/itm/King-Hauptlager-Kurbelwelle-0-25-Gehause-0-50-passend-fur-911-2-7-3-0-74-77/272824033354?hash=item3f8594604a:g:G2gAAOSwjuBZpEZ Q

Interesting I talked to king bearings in USA and they said they only had STD bearings. Now im puzzled.

you can find bearings by size. inner dia. outer dia. and lenght.

King

Whatever you do, don't overbore the #8 main bearing housing. Or the #8 bearing surface of the crank. Those normally don't wear enough to need this. And odd sizes, over OD and under ID, are even more expensive and hard to find than the other mains.

Repair case
 

I spent 16 years in Costa Rica and it will be very hard to find someone for this.Early case is light so fly back to states with each half in a suitcase and pay the $40 for the extra bag.Most shops down there are open air and the dust is free and quality is low.Have it done here.You never get your money back in C.R.if the work is shoddy.Ciao Where are you in C.R.?

Thanks for that tip I will tell the machine shop not to grind all the journals! Never thought about that this is why these forums are so important.