Engine and Transmission Tech

We took Phillip Leonard's RV8 racer out this weekend. Didn't do very well. The car ran great, but it had a problem with loss of oil pressure after about 7 laps on the Heartland Park track. When the driver slowed down after switching off the engine and then restarted it had good oil pressure and he was able to drive it back to the pits without problems. We found that we had pumped about 2 quarts of oil into the vent tank and some other loss around almost every point on the valve covers. No leaks and didn't show any signs of excessive blow by in the pits. I suspect that we were pumping all the oil up to the top of the engine and it couldn't drain back quick enough. Anyone have any experience with similar problems or any ideas on how to restrict the oil flow to the upper end without risking damage to the valve train?
Engine is basically a pretty stock 3.5 with around 10'5:1 compression and a single 4 barrel intake. Currently running a V8 T5 with a 3.9 rear gear and a 6500 rpm redline. Driver was running the whole track in third and fourth gears.

Bill,

I am so glad you encapsulated the oil problem we ran into Saturday (4/30/11). Here you've described to the V8 Forum group our problem and maybe we will get many suggestions of solutions and then a consensus of what corrections need to first be made.

Seems to me that the oiling, breathing and venting problem has been around for many years with various early Rover 3.5 and 3.9 aluminum block V8 engines.

Suggestions - please - anybody ...

keep them on the track,

phillip g

Holes in rocker shafts are pointing "downward" ? Exact clearance between shafts and rockers is ? Perhaps run-only motor with "splash tray/cut-out cover", to observe ? Type of rockers/shafts ? If the're "needles", you will need restricted oil feeds.I 'm hoping your NOT using stockers. Good Luck, roverman.

Thanks Art, don't know what type of rocker arms are being used, another guy built the engine but I'd bet it mostly stock parts as it is only a test "mule" to get the chassis sorted. Hard to find the source as the problem has only come up after 5 or 6 race laps on the track, in the pits and on the dyno there was never a trace of oil problems. We ran the car last year, but only a very few laps and at relative low speeds because of the rear gear ratio at the time.

Hey Bill,
I've battled the same problem on a friends BGT 3.5v8. It is a street car but gets used on some track days when he's bored with his race car.
To me the problem has been threefold.
#1 the block doesn't breath. The only ventilation that it has is through the cam shaft area which is quite small with the cam and lifters in place.
This leads to problem #2. With the engine running at high speed the cam picks up a lot of oil, which aided by the crankcase pressure and the sharp edge of the block opening, fills the valley with oil.
Which leads to problem #3. The design of the cylinder head causes it to collect oil. For some reason the drain back holes are at the top of the head. When running, the valve covers have a litre or more of oil in each one. Couple this with a valley full of oil and little drain back area from the heads and you puke oil out everywhere.
So what worked for me was, venting the block through the timing cover ( didn't want to drill the side of the block ), opened up the drain back area around the cam and gave the edges a good big radius biased back into the block, drilled the sides of both heads and put in two drains per side back down to the oilpan ( must terminate below the oil level).
Haven't had a problem since.

Hope that helps
Fred

That's what I was hoping for, someone who had seen the same symptoms. Fred, your reasoning and solutions sound right on, definitely something we will try.

This car "should" be generating over 1G lateral. This is tough territory for a wet sump to work in.The outboard bank/ cylinder head,(in a turn), will tend to flood with oil ,as it easily climbs out of the 45deg lifter valley and approx. 45deg. drain back angle in the heads. I strongly suggest you build a proffessional quality "race" engine, including a dry sump. A proper dry sump system will make more hp. AND save the motor ! Did I mention, you can "lower" the engine ? You guys have a beautiful/aero car, that is built well. Let's do the motor, just as impressive.I suspect your "serious" competititors, are using dry sumps. Phillip, please pm. me. Sincerely, roverman.

That's the plan for the future Art, a true race motor. Clancey Schmidt built a very nice wet sump pan for the engine with an extended sump and bafflels, should be fine as a wet sump engine if we can keep the oil down in the pan. Phil want's to find a 4 bolt main block to build the "race" engine with, the one in the car now is basically a warmed over stock Rover. Judging from the other racing MGB V8s in the photo area our venting system and pan should do the job if we can get the oil to drain back better, but that's Phillip's call, his car and his money. I figure we have all this season to run the present engine and get the rest of the car sorted out and hopefully install a better motor for next year and compete in earnest at that time. Our regular driver, Robert Malpins is recovering from rotator cuff surgery and won't be ready to drive until late this year or next spring so we have some development time ahead anyway.

Years ago, I obtained a small block Chevy that was used in dirt track racing. The entire block valley was polished smooth to facilitate oil drain back - an expensive proposition but perhaps worth the investment.



Edited 1 time(s). Last edit at 05/03/2011 10:01AM by ex-tyke.

You can polish the valley to "mirror finish", it will only help the oil climb up the 45 deg walls ! We're chasing an issue here, that is correctly solved with a dry sump system, end of story. What works for dirt track does not apply, as they don't generate the lateral g's of asphalt. Cheers, roverman.

A dry sump surely must be the ultimate solution... but for short term / partial improvement, I think Fred is on the right track. In addition to improving the Accusump installation, these two changes in particular could easily be implemented before the next outing:

1) Plug the vent bung on the driver-side valve cover:


2) Install as big a vent bung as feasible on the plate that covers the old mechanical fuel pump port:


(I've been meaning to implement these two changes on my own engine...)

One way or another, what this car really needs is track time. I bet some clubs are already renting Heartland Park for track days, and surely they wouldn't mind sharing the track and the expense of renting it. Porsche club? Corvette club? Z club? Make some inquiries. I get invitations to join my local Miata club for their track days quite frequently - they're very happy to have something different to chase around the local tracks. There are going to be other problems to sort out and refinements to be made.

Hey Art,
I'm going to have to dissagree.
Dry sump systems are not the be all end all of oil supply.
Several factors could lead you to use a wet sump system.
#1 is class rules. Often you just aren't allowed to use a dry sump.
#2 is cost. Dry sump setups are expensive to build and maintain.
#3 is weight. Extra pounds are added precisely where you don't want them.
#4 is complexity. As the parts count goes up so does the chance of something going wrong. With all the pumps, hoses, fittings, tanks, belts and brackets something is going to fail. Possibly not often but enough to put you out for the day.
#5 is safety. You carry more than double the oil capacity with a dry sump system and some day you are going to oil down the track or the car.
#6 is space. Dry systems take up a lot of precious room the may not be available.
Granted a lot of my opinion is based on rally racing where simple and light is better. You can't race a broken car. So the fewer things to break the more you win.
Besides wet sump systems have come a long way. Oil management in a wet system is light years ahead of what it used to be.
So for me, unless the situation absolulely demands a dry sump, I would favour the wet.

Cheers
Fred



Edited 1 time(s). Last edit at 05/03/2011 01:44PM by DiDueColpi.

Sounds like the same problem many people have been having after installing shaft mount roller rockers. We solved our problems by installing bushings in the head oil galleys.

Curtis, what would be the point in removing the large vent from the valve cover? I checked the files and several of the MGB V8 race cars use vents from both valve covers, although they aren't as large as this one. I do agree that the fuel pump block off plate is an ideal spot to run a vent line from. Easy to make a new block off plate from some aluminum and drill and tap it to take the necessary fitting. We already have a small -6 AN fitting to the oil catch tank, we could T off that very easily although I tend to think a larger than -6 line would be prefereable. I figure at least 1" if we can fit it to the block off plate.
Todd, can you give me details on how and where those bushings were installed? I'm not sure what type of rockers we have but that might be a factor as well. Thanks.

Hey Bill,

I would put the same great big vent on the passenger valve cover as well. Small hoses, with some crankcase pressure, make fantastic oil pumps. Angle it inwards just like the left one so that if the valve cover does fill with oil it won't dump into the catch tank on a hard turn.
Also put a drain from the catch tank back into the oilpan. This can be a relatively small hose if it enters the pan below the oil level.
You will need some sort of deflector or baffle at the fuel pump flange as the timing chain will be firing oil right at it.
Use the biggest dia hose possible from the pump flange. And if it enters the catch can on the bottom it could be used to drain any captured oil back to the engine instead of a separate drain hose.

By the way I love that car.
"Go get em".

Cheers
Fred

You might consider a blow-by gage, in that excessive amounts will aggravate oil control, out the breathers/etc. You might want to consider using a modified EGR pump, for negative crankcase pressure. roverman.

Art, we thought about excessive blow by as a cause at first, but the loss of oil pressure means that the pan has to be getting low and blow-by by itself wouldn't account for that except as a cause of the oil not draining back into the pan. With the valve covers full of oil then with the venting system we currently have any crankcase pressure would have to force oil out of the engine. The idea Curtis had on venting the timing cover at the fuel pump block off would vent the crankcase below the valley and hopefully not force any oil out of the engine, but would it also solve the drain back issue? We'll have to experiment a bit and find out. Since we have limited track time available we'll probably try several of the suggested solutions before going back to the track in hopes one or all will solve the problem. The car seems pretty good but until we get the oil under control we won't be finishing any races.
For those of you with more experience on the Rover/Buick engine, is the sheet metal valley cover strong enough to install a fitting for a drain back or vent? For the car that would be an easy place to install a drain back line from the oil catch tank. I know it wouldn't drain back during engine operation, but at least after the engine is shut down we wouldn't loose the oil in the tank as we do now when we manually have to remove the tank and drain it.

Bill, your rocker shaft oiling holes are rather critical with roller rockers, since the needle bearings offer no restriction to oil flow whatsoever. If used with stock shafts oil flow will be completely uncontrollable. The feed holes in the shaft are the correct restriction point, as restricting oil to the shaft will result in uneven oiling front to rear. Sorry I can't advise you on the correct feed hole size, but a 1/16" diameter hole may be quite a bit too large. Needle bearings require very little oil and even a .010" hole should be enough as long as there is nothing in the oil to clog it. That would be my main concern with small feed holes.

A stock shaft can have feed holes as large as 1/8" but they are on the bottom and the bushing provides plenty of restriction. The same shaft with rollers would have about the equivalent of nearly a 3/8" open oil galley firing 45 psi oil into the valve cover which I'm sure you agree would be a problem.

JB

Bill Davidson, who assembled the engine, is back from Key West and I just got off the phone with him. The engine is running stock rockers, shafts, etc. so excessive oil from those shouldn't be the cause of the problem. We'll address the venting and drain back issues as soon as we can and report back. Thanks to all for the help and information.

Sounds like you don't want to pull the motor-understandable. Draining the catch tank into a modified sheet metal gasket sounds problematic.When you need to replace that gasket ? Fred's idea of draining excess oil into the pan, is a good one. Taking oil out of eack outboard corner, of the heads ,and draining into the pan should work. If you choose not to pull the heads,, "maybe"draining, just above, with ports in the valve covers, would work. Consider draining the catch tank (a) into the pan or (b) through a pipe tapped hole in the fron/rear China wall,(each end of the lifter valley).I wonder if a small electric scavenger pump,ie. fuel or water, sucking oil from the problem areas/discharging into the pan, would work ? Good Luck, roverman.