[T3] cranks and clearances

bobsnotch at aol.com bobsnotch at aol.com
Sat Aug 15 13:39:49 PDT 2020

Personally, I'd contact Steve (Clatter) on the Samba in the type 3 forum, as he's really a type 4 engine guy with a lot of experience with type 4 engines (has enough parts laying around to build a couple if needed in his engine room). You wouldn't have anything to loose but some time, and getting a second opinion from someone with experience never hurts. He even built a "sweep the floor" engine (showed the build up on STF) that went into his bus that he took the family on vacation with. He pointed out some things that not many people know about when building it that made some sense, and some of it could be thought of as off the wall. He does have a tendency to ramble on at times, but that's how he thinks at times. While we might talk to ourselves, he types it out in messages. He's also building a really nice, very well executed 67 Fastback with a t-4 in it. Give him a shout, maybe he can help.Bob 65 Notch w/sunroof
-----Original Message-----
From: Keith Park <topnotch at nycap.rr.com>
To: type3 at vwtype3.org
Sent: Fri, Aug 14, 2020 9:00 pm
Subject: [T3] cranks and clearances

Ok, Im getting Cranky!


The crank that was in my 2056 was a 10 under, thats fine, but for some
reason despite my measuring .003 to .0035 main bearing clearances, it

to sieze when it got warmed up with the break in oil in there, what is
additionally interesting is that the sacrificial bearing shells didnt do
their work very well,

you can run your fingernail across the journals and feel some light scoring.


The crank for this build is my spare, its seen alot of use and despite
having 2 rod journals shells well into the copper the machine shop found it
in the middle of the 

spec and just polished it, and it does, and did look good, except... the new
bearing shells on it are a bit loose.


These are old stock Repco bearings, and im finding between .0045 for the
split one to .005 for 1 and 3.  Now im measuring this with a mic and bore
gauge, using the mic's 

measurement for journal size as the 0 point for the bore gauge, so it should
be accurate.  Bearings all torqued into the case.




im kinda porked... the wear limit is .006 or so, so I should be around .002
or 3, and the bearings are what the bearings are, the crank SHOULD be in
spec, if the shop measured it properly

and since they have better equipment that I do....

Should I have it taken down 10?  well.. they say its in spec NOW... and 10
under didnt do wonders for the hardness layer on the last crank and since 2L
Porsche cranks dont grow on trees... risk it

or run the .005 with the stock journals and stock hardness layer intact?
after the incident with the break in oil im inclined to keep things on the
loose side of ideal but past builds have had

oil pressure issues so its sensitive to that, although the previous build
had NO pressure issues.


What to do?  What are people finding the main bearing clearances to be out
there in stock size land?  they  are sending me a set of silverlines to try,
but they arent the quality of the Repco's.





Topnotch Restorations

topnotch at nycap.rr.com


71 Squareback  "Hothe"
65 Notchback  "El Baja Rojo"

93 RX7  "Redstur"

13 Subaru Outback "Blendin"



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