Oil pressure issues and the Regs

#1

I think that we should consider adjusting the regs to accomodate some flexibility re. oiling. This is my second season and I’m replacing bearings for the second time. I met a kid at CMP this weekend that is working his way thru the DE ranks to join us. His 5th motor failed this weekend. All failed due to oil related problems.

I don’t know enough about M20 oiling to provide decent answers, but I think that the oil problems are detrimental to the series because they can significantly increase cost. If the rules said “everything about oiling is free”, what exceptions would we need to write in to stop performance advantages?

I have a crank scraper, and so did that kid. I’m going to look into those oil reservior things that pump oil in when you’re pressure drops.

#2

Ranger wrote:

I’ll get back to you after I finish my design for a dry-sump, electric scavenge pump retrofit. No parasitic drivetrain losses…

In all seriousness, I don’t know how much benefit an Accusump provides if the problem is consistent low pressure. If the balance of the system never achieves enough pressure to “recharge” the Accusump, it won’t be there to help with momentary dips in pressure (i.e. under cornering loads).

Steve D.

#3

Do/did you run a baffled oil pan? I believe that’s legal. I have not added one, but I believe they are available for M20s and may help with the low pressure situations.

#4

I also have (had) a motor with low oil pressure…I think the problem is more related to dwindling supply of good used motors than any kind of design problem. If my motor had made any power at all, I may have put a new pump and scraper on it just to see if it made any difference.

Al

#5

The accusumps are great if you issue is momentary loss of pressure as Steve D explained. I have one in my honda and it is a must because those motors move so much oil with Vtec engaged. Maybe try a different oil. Back in the day I ran a SOHC vtec honda engine the was murder on oil temps, well over 300 consistent. The only oil I could find that would hold oil pressure at those temps was Mobile 1 15w50, since then it has been my BFF oil. We ran double duty on my spec E30 on its first weekend with no motor rebuild at 240k using mobile 1, no issues. I did put in the crank scraper though.

#6

I looked at the rules again. Which I should have done before I started this thread. The rules definately got more permissive on oil systems this year. But here’s some additional ideas:

  1. Allow remote oil filters. This would make it easier for us to attach oil pressure and temp sensors, and accusumps. Sure we can do that now, but if you make something easier, then more people will do it.

  2. Allow a restricted cam journal oiler tube. I don’t know what the real name for this is, but it’s the tube that runs across the head and puts oil on the cam & rockers. I’ve seen versions of this tube that have a smaller intake port such that less oil flows thru it. The idea is that if the oil pickup can’t get oil for a heartbeat, the quantity of oil required by the cam oiler tube contributes to a loss of oil pressure throughout the system.

To Craig: Negative on a baffled oil pan. Pricey, but maybe worth doing.

To SteveD: It’s not so much that my problem is low oil pressure. The oil pressure issue is a symptom of the underlying problem, probably bad bearings. So the goal should be 1) Keep oil pickup submerged, and 2) Help ensure constant high pressure oil to the bearings.

Just because a person is getting 60psi doesn’t mean that their bearings are getting all the high pressure oil that they need. I have never seen my oil pressure drop worth noting in a sweeper, and here I am replacing bearings again.

Are there changes that can be made to the crank and/or case that will help the oil supply to the bearings? Like maybe engine building wizards are aware that cutting some little grove in a certain place right next to the #6 rod bearing will give it a better oil supply.

When does reliability = performance? In past discussions there’s been those that have argued against some reliability based rule changes because in a sense, all reliability mods are performance mods. But lets think about that kid that keeps going thru M20 motors because of oiling problems. What do you think this is doing about his ambitions to join us?

The series has 3 pillars. Similar performing cars, inexpensive, good buddies, and hot chicks. Ok, 4 pillars. None of those 4 can fail. Oiling problems have crushed “inexpensive” for that kid. And frankly, we ain’t doing so good on the hot chicks thing either.

Subject change. I just talked to Accusump. The way to go is their 2qt system and the EPC valve. 3qts is ok, but the EPC valve is a must. The manual valve has to be turned off before you shut the engine down, making it really inconvenient, and the standard electric valve refills too slowly.

Later edit: MikeSki below says that the manual valve works well too. It’s certainly less expensive. The Accusump dude felt strongly about his expensive EPC valve, but since Mike actually uses the thing his point is worth noting.

#7

I have contacted a couple of vendors about a pan for the M20. I have developed one for my motor that limits oil pressure loss to 40psi in turn 3 at RR. Most of us saw 20psi or less there. Another problem place is 5 at RA. Anyway, I have a “T” sump 7 quart pan on my car that is begging to be built. It will be available to copy after the ARRC by whomever wants to market the pan. The only problem is Spec E30 approval. Work on it. Chuck

#8

accusumps are legal and my 3 quart setup in my honda can supply my motor with over 65 psi for around 5-6 seconds, starting at 80 psi.

BTW, I think the manual valves are the way to go. I shut mine down on the cool down lap to be sure the accusump is full. The electric ones shut down with your ignition, and after a long hot session with you motor idling, you have around 20 psi oil pressure. Considering the accusumps are precharged with around 40 psi, your accusump is empty when you shut down. It takes some thinking at first, but after a while you get used to shutting your accusump valve on the cool down lap.

I don’t have one yet in the bimmer, but after reading this, one is going in before the next event!

#9

I installed a manual valved accusump on my M30 powered car a while back and liked it and never had any oiling problems, and Mobil 1 15/50 has proven to be a good oil, those thin oils used in modern motors dont seem to work too well in outr antiques.

The hot chick problem covers all the major road race series, not sure what the problem is but you will find more wimmen at the local 1/3 mile cirlcle track than at any road race…except motor cicles of course.

Al

#10

FARTBREF wrote:

[quote]
The hot chick problem covers all the major road race series, not sure what the problem is but you will find more wimmen at the local 1/3 mile cirlcle track than at any road race…except motor cicles of course.
Al[/quote]

Circle track? Hmm. Anyone see chicks hanging around the skidpad?

#11

I just pulled the pistons out of my spare block to prepare it for the machine shop. I saw streaks of copper on my con rod bearings. I ran those bearings for 10 months, with a crank scraper and a qt high on oil. There were no symptoms of problems, but they were failing nonetheless.

I bet that every one of you has failing bearings that are just not giving you symptoms yet.

That’s it, I’m getting an accusump.

#12

Ranger -

I hate that you are having motor issues. I know you have overfilled the oil to avoid starvation issues under cornering loads, but is it possible there is an unintended consequence of the oil foaming (and not pumping or lubricating as well as a result)?

Steve D.

#13

Steve D wrote:

[quote]Ranger -
I hate that you are having motor issues. I know you have overfilled the oil to avoid starvation issues under cornering loads, but is it possible there is an unintended consequence of the oil foaming (and not pumping or lubricating as well as a result)?
Steve D.[/quote]

I’m not inclined to blame oil foaming. I think that going 1qt high is pretty common. If the crank was was hitting my oil at 1qt high, it’s foaming everyone’s oil.

I’m thinking that maybe there is a weakness in the bearing, rod or crank design that makes the bearings suseptible to oil starvation under high loads, even tho the oil gauge still reads a decent pressure.

I’m struggling a little to get my damn front crank bolt out so I’ve not been able to look at my main bearings yet. I can’t run the air compressor at night because the neighbors complain. Dragged lawyer-chick wife out to the garage last night so she could hold the fly wheel in place while I reefed on the torque wrench to get the 18,000 ft-lbs necessary to get the damn bolt off. She had problems holding the flywheel in place and my efforts on the torque wrench were either lifting the whole engine stand off of the ground, or trying to topple it over.

#14

Ranger wrote:

I sure am glad I got up and read THAT this morning! :blink:

#15

You don’t have to remove the crank bolt to check the main bearings. Just pull the pan and you can remove all the main caps.

There are two things controlling oil pressure in the M20 motor. First is the oil pump…it is a wear item and should be replaced anytime bearings are. Second is the oil pressure bypass valve…they get weak (the spring) also and that should be addressed. My race motor is set up with .002 main and rod clearances and I run 10W30 oil. Hot pressure is 25psi at 1500rpm idle, and 60-70psi at rpm. There are no pressure issues in left hand corners.

Note, oil starvation is the problem with all the main/rod bearings issues I have seen. That needs to be addressed immediately. Chuck

One thing I forgot. Those of you running the stock oil cooler and no oil temp gauge…WRONG:woohoo: If you exceed the temp capabilities of your oil, you loose lubricity. The stock oil cooler is too small for racing. The ideal setup is the TruCool 11X11" cooler and while you are at it, add an Oberg oil filter so you can monitor your motor condition.

#16

I just talked to some M20 specialists that said that the problem with the main bearings is that the bearing’s oiling groove runs only 180deg. The bearing apparently runs dry from TDC down to BDC. They can cut a groove in the bearing such that it runs 360deg and is therefore always receiving fresh oil. Our regs should allow this.

#17

Ranger, the crank runs on a film of oil. The moment that film disappears, the bearing is wiped or spun. This is the problem with the stock oil pan…oil starvation. The bearing design is not the problem! Chuck

#18

Doesn’t it take a few revolutions to run that film of oil out? Reading the last couple posts makes it sound like an instantaneous thing. My rudimentary understanding of the bearings is that they receive oil from BDC to TDC, then carry that oil with them from TDC to BDC (while some escapes to be replaced with “fresh” oil from the groove on the trip from BDC to TDC again). Is that correct?

Seems like the laundry list of a properly-fitted crank scraper, new/rebuilt pressure relief valve (anybody got a part number or rebuild spec for spring pressure?), and new oil pump might be up to the task. And cheaper than machining 360 deg grooves (which only helps if there is sufficient volume of oil being moved anyway).

Steve D.

PS - A good machining/balancing/blueprinting of the crank, con rods and pistons might remove some of the loads on the bearings. :wink: :blink:

#19

cwbaader wrote:

I understand that the film of oil idea. But we both know that the oil film is really oil flowing thru the bearing. The film has significant thickness where it enters the bearing and less thickness where it exits the bearing. It can’t help the maintenance of that oil film thickness if the supply of oil to the film is running at a 50% duty cycle.

My point is that there may be multiple weaknesses to the design of the entire oiling system. Weaknesses that our current ruleset do not allow us to fix. Is our pump optimal? Is the pressure release valve optimal? Are there more reliable bearings that we might use?

#20

Steve D wrote:

[quote]Doesn’t it take a few revolutions to run that film of oil out? Reading the last couple posts makes it sound like an instantaneous thing. My rudimentary understanding of the bearings is that they receive oil from BDC to TDC, then carry that oil with them from TDC to BDC (while some escapes to be replaced with “fresh” oil from the groove on the trip from BDC to TDC again). Is that correct?

Seems like the laundry list of a properly-fitted crank scraper, new/rebuilt pressure relief valve (anybody got a part number or rebuild spec for spring pressure?), and new oil pump might be up to the task. And cheaper than machining 360 deg grooves (which only helps if there is sufficient volume of oil being moved anyway).

Steve D.

PS - A good machining/balancing/blueprinting of the crank, con rods and pistons might remove some of the loads on the bearings. :wink: :blink:[/quote]

I’m not really disagreeing with any of what you said. All I’m saying is that 1) Folks are losing bearings, and this will have an impact on the attractiveness of the series. 2) The rules should allow more flexibility to improve their oiling systems.