Oil pressure, temperature, starvation for road race duty

[jt1]

The split collar is an ongoing, pita oil leak that's almost impossible to seal. There's just no good way to keep oil from escaping thru the split. Drag racers use them, but they're not as sensitive to oil leaks as an OT car. The only way they don't leak is if you're using a vacuum pump or dry sump system so there is negative crankcase pressure at all times. With the wide rpm range and on/off throttle of an OT engine, there's inevitably going to be positive crankcase pressure at some point, and a breather/pvc system just can't keep up. Then oil is running down the back of the block, hitting the headers, the black flag is out and when they look at you the back of the car is greasy.

 

The split collars were an answer to heavily cut blocks/heads/intakes, or tall deck blocks. They have their applications, but OT isn't one of them.

 

I like the orings on the shaft. Oil leaks from the lifter galley around the shaft, and that's oil that doesn't get to where it can do some good. Sometimes they are tough to install. Before a block gets a final cleanup, I like to put a small chamfer on the dist hole in the block.

 

Sometimes with a standard distributor, the gear contact isn't what you would like, and you may have to shim the gear, or entire dist, up or down. You can do that, if needed; lots of times it's not, but it should be checked. You will never get the split collar to stop leaking.

 

jt

Edited December 10, 2011 by jt1

[jhm]

bj-

Very interesting thread.....I've been following and learning new stuff all the time.

 

Regarding your question on thick vs thin gaskets.....if I'm not mistaken, pre-75 engines used the thin gasket (approx 1/4" thick); 75 and on used the thick one (3/8" - 7/16"). However, this is only true when using the stock factory pan from the same year. If you're using any other pan, these rules may not apply.

 

Don't know if you've already figured out the solution to the oil leak; but if not, the above measurements may be of some assistance.

 

Finally, I'm amazed at how little torque is required for the oil pan bolts (and how easily the pan and seal can get distorted if too much torque is used, even when employing stiffener plates). I think 100-140 inch-pounds is the norm.

 

Good luck, and be sure to post your results!

- John

[bjhines]

This issue with Positive Crankcase Ventilation came up many years ago with my very first posts to this forum. That was on an L24 engine, but I used the exhaust pulse vacuum tubes offered by MrGasket or Moroso to provide vacuum under full throttle. The system used a PCV in the intake manifold and an additional exhaust pulse vaccum tube Tee-ed into the PCV system. It would pull a slight vac under all conditions and that motor stayed dry on the outside for dozens of track events.

 

I think I will add 2 of those to this system. Winter project.

Edited December 11, 2011 by bjhines

[fastzcars]

I had the same problem with my MSD billet distributer with the split collar. It took a long time for me to find that darn leak!!! I used a very thick o-ring that took the place of the gasket/shims that just fits snuggly around the case of the dist collar.I then placed a small amount of silicone on the split itself for insurance. I hope that helps. I'll try to take some pictures tonight.

Edited December 19, 2011 by fastzcars

[bjhines]

Thanks FastZcars,

 

After test fitting several parts. It takes a thick front seal to properly fit the Edlebrock 2-piece front cover. Indeed, a thick seal fits like a glove and seals well. The oil pans are not the important factor, It is FIRST the Dipstick location(left<=79<right), and secondly the front cover design(thin<75=<thick). But really folks... Even the INSTRUCTIONS for the Edelbrock cover don't seem to mention the exact year or the thickness of the front seal. They supply a front pan-seal in the timing-cover kit, but don't mention it's thickness, only it's part number(#54-0607) which NOBODY sells.

 

I got the collar sealed with some black RTV... Underneath, injected in the split, and on top between the collar and hold-down clamp. It may or may not stay in place, but I did get a good seal that I tested with a smoke generator to a few PSI.

 

The engine is the only part of this car I did not build myself. It has been the most dangerous and challenging source of problems in this entire build. I will NEVER!!!! EVER!!!! again buy a complete engine from another home builder. There is no continuity or documentation. Note to self... BUILD THE DAMN THING TO A SPECIFIC YEAR!!!!!! Use all the aftermarket parts you want but build it to suit a detailed set of replacement parts from a specific year. I cannot stress enough how important this is if you EVER try to get gaskets at a track event, or on a budget.

 

-------------------------------------------------------------------------------------------------------------------

 

Now, about the buildup of pressure inside the engine...

 

I am adding the Crankcase Evacuation Kit offered by MrGasket. I am routing from the top of both valve covers to a catch-can. PCV to the intake works for part throttle operation and exhaust pulses work at moderate to full throttle. In my experience the evac tubes use exhaust pulses and a check valve to generate significant flow but low actual vacuum. Obviously they work better on open headers, but they will still pull considerable flow with a good exhaust and mufflers.

[luigi]

After the pan install, did the accumulator "on" light stay off?

thanks for keeping us posted about this.

[bjhines]

No more starvation problems at all. The windage tray, pan baffles, extra capacity, and trap doors keep everything under control. I run the oil level so it just barely shows on the stick. It has plenty of capacity to deal with the accusump discharge.

 

I added the crankcase evacuation system and got some initial testing results. The system uses PCV and exhaust pulse generators.

I have PCV drawing 15" vacuum with a low flow rate at idle. It takes about 30 seconds to draw 12" of vac in the crankcase at idle. PCV will not maintain crankcase vac under load.

I have exhaust pulses drawing 6" of vacuum at part throttle with a high flow rate. Exhaust vac fluctuates with throttle blips but seems to maintain at least 5" under all but full throttle high rpms.

The two sources together maintain good vac under all but sustained full throttle operation. The crankcase vac is never worse than 2" vac as far as i can keep my foot in it on the highway.

[rsicard]

bjhines:

 

I may be faced with the same oil starvation issue. Would like to Road Race my 1971 Datsun 240Z with a 383 stroker. A racing pan is installed with windage tray, pan baffles and 8 quart capacity. Also have a pressurized oil reservoir on the shelf that can be installed. Have you cornered you Datsun hard enough to have the accusump discharge into the Engine?? Also is there a re-stricter in the PCV line to the manifold vacuum?? If so what size is the re-stricter??

[bjhines]

I had starvation with the early corvette pan. I had a lot of other problems as well.

 

The pcv valves have a variable flow rate that is tailored to a specific application. I pulled a bunch of pcv valves out of their boxes and blew thru them to find the one with the most flow and suitable connections. Most any V8 engine pcv is a good start.

[jt1]

John, where did you put the tubes? I tried a set, couldn't get them in the collectors, put them in the cones right past the collectors, and only had so-so results. Vac at some rpm, but not all.

 

jt

[bjhines]

I have installed these pulse/evac tubes on several vehicles. I have used these exclusively on vehicles with full, performance exhaust and free-flowing/loud mufflers. The main problem has been the poor quality of the check valves that come in the kit. I am using 1984 Ford 5.0 truck A.I.R. check valves that were designed to screw into the exhaust manifold AIR distribution tubes. They can handle the heat and they work very well.

 

There is no real trick to installing the tubes. Pay attention to the instructions and place them where the exhaust pulses are at their maximum amplitude. This is right after/at the collector. The further downstream you place them the less amplitude the tubes have to work with. You want about a half inch of the tube sticking into the exhaust pipe. This minimizes odd flow effects on the wall of the exhaust pipe. There is no Bernoulli effect or other fancy **** going on. I have seen a lot of folks who insist on turning the tubes 180 so that the slash cut end is perpendicular, facing downstream. I dunno how that works for them but it really gets in the way of exhaust flow.

 

You can expect 3"-6"hg of vacuum from these with much more flow than the PCV can deliver. The pulse tubes work pretty well at idle up to full throttle, mid-RPM. There is too much positive pressure in a full exhaust at WOT high-rpm for these to work well. I still prefer the excess crankcase gases flowing into my exhaust instead of my air cleaner.

 

 

 

 

 

...

[rsicard]

bjhines:

 

I really like your system of evacuating the crankcase. Noticed that the two AIR evacuation tubes and valves are "Td" together at the front.

 

Question 1: Does the common AIR evac tube "T" together with the manifold vacuum line going to the PCV valve? Or something else?

 

Question 2: Have you cornered your Datsun hard enough, at speed, to have the accusump discharge oil to keep oil pressure into the Engine? Please elaborate.

[bjhines]

The tee in the line runs up to a custom made catch can.

 

 

 

 

 

In the beginning, I had 3 problems, low pressure when hot, over heating the oil(water is fine), and starvation in right hand turns after hard braking zones. The 3qt accusump did it's job well even with low system oil pressure.

 

...

Edited December 29, 2011 by johnc

[bjhines]

I got my hands on a 12v electric pump from an LS1 GM smog system. The pump weighs 2.25 pounds and draws 11A free flow, and up to 20A restricted flow. It achieves highest vacuum(4"hg) at 17A with a small amount of airflow. The pump runs cool with air flowing through it. The impeller housing gets hot very quickly when the airflow is stopped or severely restricted. I think the heat is from the impeller, not the motor, although it does draw nearly twice the current when stopped up.

 

 

 

 

 

 

The turbo-Buick guys are using these pumps only under boost. That means pump-duty is intermittent and likely has a lot of airflow. I would be concerned about overheating the pump under continuous, high vacuum/low airflow conditions. For this reason, I would use a micro switch on the throttle or a vacuum switch to shut off the pump under high vac conditions.

 

 

...

Edited December 29, 2011 by bjhines

[boggero]

Did you already remove the sponge that is in there? it runs cooler without it, i use it for daily driving and it works great, you can even use it with a switch, it sounds different when theres vaccum in the engine. its going to work great with a vaccum switch, i have been using it for 8 months now.

 

 

 

 

[bjhines]

see there.... Look at you... Got this thingy going all ready and I am just beginning to figure it out. It appears that mine already had the foam removed. I would mount the pump assy with the motor UP. You have it DOWN and oil will collect in the rubber bulb that encloses the motor. We may even need a drain in the plastic cover with a one way nipple to drain liquids when the pump is off.

 

 

I am looking for vacuum switches. I can't seem to find many automotive versions. I have found some industrial and refrigeration related parts, but they are very expensive(>$100).

 

So... The pump pulls excessive current at +4"hg vacuum. I should limit it's operation to below 3" vac or so.

 

1. A 3" vac switch hooked into the crankcase or recovery canister should do the trick. The pump would cut off when crankcase vac approaches 3" and we are good. PCV valve should do the trick at idle and part throttle.

 

2. A 10" vac switch in the intake would cut the pump off whenever the intake vac is greater than 10". This would indirectly control the pump when PCV valve is capable of providing flow. The pump would only turn on when the throttle is mid to WOT.

 

3. A micro switch on the throttle would cut the pump on at mid to WOT. This would ensure that the pump only works when the PCV cannot. This is another indirect approach but it would work.

 

4. A relief valve that would open to atmosphere to allow free airflow for the pump under high crankcase vac conditions. The LS1 A.I.R. system came with a large 5/8" port tee that opens when 10" vac is applied to the diaphragm port. I could plumb this to intake vacuum to open up the port on the tee when PCV can do the work. This would allow me to run the pump all the time and simply relieve the load on the pump.

 

5. I could combine several switches into a logic controller that could do many things under different conditions.

 

 

hmmmmmm.....

Edited December 29, 2011 by bjhines

[boggero]

see there.... Look at you... Got this thingy going all ready and I am just beginning to figure it out. It appears that mine already had the foam removed. I would mount the pump assy with the motor UP. You have it DOWN and oil will collect in the rubber bulb that encloses the motor. We may even need a drain in the plastic cover with a one way nipple to drain liquids when the pump is off.

 

 

I am looking for vacuum switches. I can't seem to find many automotive versions. I have found some industrial and refrigeration related parts, but they are very expensive(>$100).

 

So... The pump pulls excessive current at +4"hg vacuum. I should limit it's operation to below 3" vac or so.

 

1. A 3" vac switch hooked into the crankcase or recovery canister should do the trick. The pump would cut off when crankcase vac approaches 3" and we are good. PCV valve should do the trick at idle and part throttle.

 

2. A 10" vac switch in the intake would cut the pump off whenever the intake vac is greater than 10". This would indirectly control the pump when PCV valve is capable of providing flow. The pump would only turn on when the throttle is mid to WOT.

 

3. A micro switch on the throttle would cut the pump on at mid to WOT. This would ensure that the pump only works when the PCV cannot. This is another indirect approach but it would work.

 

4. A relief valve that would open to atmosphere to allow free airflow for the pump under high crankcase vac conditions. The LS1 A.I.R. system came with a large 5/8" port tee that opens when 10" vac is applied to the diaphragm port. I could indirectly plumb this to intake vacuum to open up the port on the tee when PCV can do the work. This would allow me to run the pump all the time and simply relieve the load on the pump.

 

5. I could combine several switches into a logic controller that could do many things under different conditions.

 

 

hmmmmmm.....

 

i already open a hole in the rubber bulb and i was expecting it to work cooler that way, but it works exactly the same way lol , it takes the same amount of time to heat it. also tried it with a oil catch can before the vaccum pump , it works the same amount of time before it heats and it did not collect oil at all . also i made the mistake of putting it close to the header, try to put it somewhere it recives cool fresh air, that might work better than what i did

Edited December 29, 2011 by boggero

[boggero]

since we are talking about vaccum pumps ,here is another cheap fix for the people that has low vaccum in their brakes with huge cams,

 

An ebay vaccum pump of a Volkswagen Passat Brake Vacuum Pump they are around 40 to 60 dlls, and they can work all the time, they never heat or have problems.

 

My dad uses it on his camaro it has a lt1 396 and a huge cam, it idles at 800 rpm and the brakes always work

 

 

 

[bjhines]

That's another one I might try to find cheap to test with.

Edited December 29, 2011 by bjhines

[surpip]

I run that pump on my El Camino and it works great no problems for several years now. I have it on a kea on relay with a 15Amp fuze 12Ga wires never get hot