<VV> CRANkCASE PARTS

[Tony Underwood]

At 12:26 PM 1/24/2010, Mark Durham wrote:
>Tony;

I assume you meant Larry...  ;)


>If you have current running engines that otherwise have no urgent 
>issues, you may want to look at oil pump wear.


This was my suggestion to Larry, via my oil pump rotor wear comment.   :)

>All the oil goes thru there and they do wear. Try tightening up the 
>clearances there. If the gears are scratched up, replace them. If 
>there are deep gouges in the housing, replace it. The cover can be 
>polished smooth by using emery paper and water on a perfectly flat 
>spot (I used my granite counter top when my wife wasn't home)


I've done it with a D/A sander with stick-on 280 grit paper.   It was 
fun holding onto the pump cover...


>Another option would be to add a higher volume pump to the engine. I 
>also added the longer pressure relief spring to mine to keep 
>pressure higher overall. Of course, if you have a confirmed flow 
>issue, a heavier duty spring won't raise pressure until a pump 
>capable of exceeding the needed flow is installed and adjusted correctly.


Agreed.   A hv pump would help there.   It certainly beats the 
alternative of tearing down the engine to work on the case halves to 
snug up the cam bores.   I'm not so sure that slightly loose cam 
bores is all that desperate a situation if you can keep good oil flow 
to the bearings via a HV pump with a bit of extra pressure on the reg spring.


>That would be an easy and relatively cheap way to troubleshhot the 
>problem as well. Add the higher pressure spring, if the low oil 
>pressure problem quits, it was just a weak spring.


It's a pretty good idea to attach a gauge and check it closely after warmup.



A good pump will easily hold at least 30 lbs (stock) hot, at road 
speed rpm if you're using good oil (and not some obscure 5w20 stuff 
or something similar).   I use 10w40 in everything and never had any 
problems with any of them.

There's an old rule of thumb that says you need about 10 lbs per 1000 
rpm, minimum.  That means at idle, if you have at least 10 lbs of 
pressure you're likely ok, as long as you have around 30 lbs at 
around 3000 rpm.   Unless you're gonna be running the engine VERY 
hard, you won't need much more than 30 for most things...


I'd go with at least 40 for a street turbo engine or a 140 that's 
likely to see "spirited" driving.   That's oil pressure you have in a 
warmed up engine once the pressure relief spring starts bypassing oil 
pressure.   Not really necessary to have much more than that unless 
the engine is tweaked and you're going to Lime Rock or VIR and flog 
the Hell out of it... which means you've likely already gone hv and 
high pressure from the beginning.

My original '60 engine, with almost 200k on it, never apart, would 
hold 12-15 lbs at idle, hot, and 35 at highway speeds.   Never 
worried about it until it swallowed a valve which had nothing to do 
with oil pressure.  ;)   I always used good oil.  Check those 
ratings.  Only costs a nickle to go first class...  don't skimp on 
quality oil in a Corvair... they're hard on engine oil as it is, even 
on a good day, and on a hard day they can be ruthless.   Synthetics 
are pretty decent these days although I still use premium grade dino 
juice in mine... for now.    What with Rotella now skimping on zinc, 
I'm looking at synthetics seriously.


tony..