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View Full Version : Anyone road racing a chevy bigblock with wetsump?



herr_bob
01-08-2008, 06:01 AM
Hi,

This is my first post so be gentle ;)
Well heres my question:
Im trying to get my 69 Nova BB car ready for some trackdays. But now ive heard that chevys big block isnt realy good for road racing since it cant hold up the oil pressure after accelerating-braking-and turning.
The problem (someone told me) is that the oil doesnt return back to the oilpan from the valvecovers fast enough. One solution would be to install a "accusump" that helps keeping the oilpressure up when the oilpump runs out of oil.

But this wouldnt help the fact that the oil still is in the valvecovers.
My engine is a Mark IV 396CBB, headers, performer rpm intake and a 770 holley street avenger. Planning to buy a milodon road race pan with high perf. oil pump.

Since I dont want to change my bigblock to a smallblock yet, and I dont have the knowledge to rebuild my motor with a drysump, any ideas would appriciated.

Regards Niklas

Blown353
01-08-2008, 07:00 AM
A good pan and an accusump is ALWAYS a good idea on any wetsump road race setup... especially if there are slicks involved.

As far as oil drainage from the heads, you can do what the drag guys do but on both sides of the head-- install external drain hoses from the valvecover area down into ports on the oil pan. I've seen them installed on the front, rear, and outside of the head just below the valvecover rail to provide extra oil drainage paths. The drag guys typically install them at the back of the heads only, but I have seen some wetsump BBC roadrace guys with up to 4-5 external oil drainage hoses. Granted it's more effective in a drysump setup where there is some crankcase vacuum to help "suck" the oil out of the valvecover area, but it's supposed to work on wetsump setups too. I have never personally tried it though.

Lowend
01-08-2008, 08:42 AM
Yep - you have to install drain backs in the heads... Good old -8 AN lines to the oil pan will work.

You will need to come up with a remote breather setup as well for PCV

Blown353
01-08-2008, 12:04 PM
Yep - you have to install drain backs in the heads... Good old -8 AN lines to the oil pan will work.

You will need to come up with a remote breather setup as well for PCV

That is a very good point on the hose size. Being wet sump and having only gravity to help drain the valve covers you're going to want a larger diameter hose.

Most dry sump guys can get away with -4 or -6 since the pan/crankcase vacuum is actively sucking the oil out of the valvecover area.

Vinz68
01-08-2008, 02:36 PM
I have a canton road race oil pan on my 496BB. I have aoutocrossed and ran a track day so far and oil pressure has been fine.

vintageracer
01-08-2008, 03:40 PM
There are still some Corvette racers running dinosaur BB's in Vintage racing, but very few. They typically run slower lap times due to the additional weight and the fact they most driver's do not have the skill to use the extra power/torque. So the answer is yes, you can run BB's and they will last to a degree. Contact some Corvette vintage racers for more information on how to make a BB last the rigors of road racing.

Small blocks rule in production type vehicles vehicles such as Corvettes, Camaros, Novas, and Mustangs in road racing!

herr_bob
01-09-2008, 04:15 AM
Thanks for the response.

Vinz68: do you only have the canton oilpan?, or do you have any other "oil mods" on your engine?
What gen CBB do you have? I have gen IV thats why I ask...
Did you have any problems fitting the headers with the T-style oilpan?

I probably try a road race pan and maybe the accupump, and if it doesnt work at all
:drive2:
then maybe Ill buy a crate smallblock.

Regards Niklas

wendell
01-09-2008, 06:08 AM
There are still some Corvette racers running dinosaur BB's in Vintage racing, but very few. They typically run slower lap times due to the additional weight and the fact they most driver's do not have the skill to use the extra power/torque. So the answer is yes, you can run BB's and they will last to a degree. Contact some Corvette vintage racers for more information on how to make a BB last the rigors of road racing.

Small blocks rule in production type vehicles vehicles such as Corvettes, Camaros, Novas, and Mustangs in road racing!

True but when they do know what they're doing; Sweet Jesus they're fast! There's a blackw/ red 69 hard top from SF or Portland that comes to mind. Damn that car is bruetal. The orange #20 '67 roadster from NY also goes pretty good. But I digress.

If it's just something you're goofing around with, put the best pan you can under it, drive it and see what your oil preasure looks like. If it's wobbly, get back to it. If it holds up; you're having fun!

David Pozzi
01-09-2008, 07:35 PM
Do the same as I'd do with a small block, use a solid lifter cam, roller rockers, and install oil restrictors in the lifter galleys. I believe they have .060" holes in them.This restricts the oil entering the valve covers. If you have hydraulic lifters, I don't believe you can use the restrictors, in that case, drain back hoses from heads to pan are your only alternative.

Another thing I've found is if you can run a PCV valve, it really helps aid drain back.

The other end is to use a good pan with trap door baffles and extra capacity, and don't use excessive oil pressure.

You can "get by" with less, but it all depends on the track configuration, and how hard you run the car. A hair pin turn after a long straight is going to be trouble if things aren't exactly right.

I like the Accusump, it won't make up for a poor system overall though.
David

Lowend
01-09-2008, 10:29 PM
I kinda considered the Solid Roller Lifter cam a given... but David is absolutely correct
In a perfect world I would also be running coated engine bearings for extra insurance. I recall my old buddy Paul's Vette dropping oil pressure in the Sears point carousel and it had a dry sump!
Honestly the BBC is a capable engine for Road racing, you just need to prep it.

herr_bob
02-05-2008, 12:16 PM
So I bought a milodon road race oilpan, but there is a fitting I dont know what to do with. Any ideas?

https://static1.pt-content.com/images/noimg.gif (http://img246.imageshack.us/my.php?image=milodonoilpanza2.jpg)

Regards Niklas

Lowend
02-05-2008, 02:45 PM
That is for an oil temp sensor

HILROD
02-05-2008, 03:23 PM
Some kickout pans use that hole for a dipstick, as they have no other place for them.

TD509EFI
02-05-2008, 05:49 PM
Looks like the same Milodon pan that I'm using on a BBC. I use that fitting for a oil temp sensor.

John

herr_bob
02-05-2008, 10:43 PM
Looks like the same Milodon pan that I'm using on a BBC. I use that fitting for a oil temp sensor.

John

Yes you are right, it must be for a temp sensor. I tried my water temp sensor and it fits perfectly...
Its not for the oil dipstick since that hole is on the other side.

Thanks for the replys :)

Davezz28
02-14-2008, 08:05 PM
I built the car and motor for Dave who posts here as Orngcrush. It is a 69 Chevelle with a BB, and he runs track days with the car and has no problems with the oil system.

I used a moroso street pan (tried to talk him into a RR pan, but he was on a budget) and I like to use the STD volume pump with a Hi Pressure spring. I think people get all wound up over hi-volume pumps and do more damage than good. I believe (and this is my opinion-if you have a different one thats ok) that a Hi-volume pump can pump an oil pan dry as the oil can't drain from the heads and lifter valley fast enough. If you have your bearing clearance right, you don' neet the extra volume from the pump.

So...I guess what I am getting at is...A BB on the track is great, just pay attention to details when building the motor.

TonyHuntimer
02-14-2008, 10:50 PM
I built the car and motor for Dave who posts here as Orngcrush. It is a 69 Chevelle with a BB, and he runs track days with the car and has no problems with the oil system.

I used a moroso street pan (tried to talk him into a RR pan, but he was on a budget) and I like to use the STD volume pump with a Hi Pressure spring. I think people get all wound up over hi-volume pumps and do more damage than good. I believe (and this is my opinion-if you have a different one thats ok) that a Hi-volume pump can pump an oil pan dry as the oil can't drain from the heads and lifter valley fast enough. If you have your bearing clearance right, you don' neet the extra volume from the pump.

So...I guess what I am getting at is...A BB on the track is great, just pay attention to details when building the motor.

Said like a pro. :)

Tony Huntimer
RaceHome.com

herr_bob
02-29-2008, 07:39 AM
Thanks for the input, when I ordered the 8qt milodon RR pan I just added the milodon high pressure pump and pickup as this where "required parts". But maybe this is just a trick to sell more stuff :hmm:

And now when I have the parts I guess I just put it in and se what happens.
IŽll go back to the old pump and pickup if it doesnt work :pat:

Regards Niklas