Chev rear main seal conversion (for dry sump/vac pump)

**TK383** · 26-11-2014, 02:49 PM

Something I've been working on / thinking about & finally got around to doing a couple of weeks ago.

With the regular setups for holden rear main seals you have choice of rope or a neo conversion using a buick seal - rope works great unless you want to spin it hard, then the suckers burn. The buick seal conversion has a problem in that it is a narrow single lip seal - they have a tendancy to weep when spun hard & don't last real long.
Neither of the options works with crankcase vacuum, they will both allow air to be pulled past the seal into the crankcase.

Chevs have lots of seal options, including double lip seals for use with vac pumps/dry sump.

So, I figured out how to stick a chev seal into a holden, bit of machining involved & the seal area of the crank needs to be ground to chev size:

Seal area line bored out:

Seal adaptors machined in the lathe (cut in 1/2 1st, then held together & machined):

Adaptors drop in to the block & are located by whats left of the original seal groove:

Bingo, she'll take a chev seal:

Adaptors are permanently attatched with epoxy applied in the original seal groove, bolt the cap down & wipe off the excess epoxy then leave to cure overnight:

**Smitty2** · 26-11-2014, 03:12 PM

... another thread as a sticky

thanks TK

**Lostit** · 26-11-2014, 03:15 PM

Good worng mate !

But remember about running the seal in reverse. if running huge vaccum !

**TK383** · 26-11-2014, 03:30 PM

Nah, don't need to reverse the seal - you use a specifically designed double lip seal, one lip faces in each direction so it seals against oil getting out as well as air getting in.

**PANTERA** · 26-11-2014, 10:23 PM

That's awesome mate, thumbs up!!

**RedTaxi** · 27-11-2014, 11:13 AM

Looks good. Bit of work there. (read $$) My machinist mentioned boring out the arse of my block to fit a chev seal. Not sure if his trick included the adaptor rings, I will ask him.
I just went buick neo seal in the end. Good so far, not a drop.

**Hqtunna4me** · 27-11-2014, 01:31 PM

what would something like these cost?

**J.A.W.** · 27-11-2014, 06:10 PM

Bloody good effort.. TK.. & be sure let us know - how she pans out under a decent floggin'..

**AED** · 15-09-2015, 07:16 PM

Good one TK,
I have been looking at this for a long time. One question, what do you do with the seal area diameter difference, do you turn or grind it down? My crank man wont grind it because it is too narrow. I just had to modify a 355 crank last week to suit a neo block. Pain in the a$$e.