Dry or Wet Sump

[Strobe]

I have been discussing with my engine builder option of running and dry sump instead of a wet on my Ford 302. Mine has come with a double humper and was concerned about baffle arrangement inside.

I am led to believe this design in itself does not require any internal baffling to ensure correct distribution.

Recommendation was that dry should not be a concern until the horses go through the roof??

Any comments/findings/experiences

Cheers

 

[Ian Clark]

Hi Stephen,

You could go with an Armando http://www.geocities.com/motorcity/flats/1624/race.html or Aviaid http://www.aviaid.com/ pan. They're both wet sumps as original. Aviaid actually supplied the original cars. Dry sump is fun to say, no fun to do and not neccasary with these pans.

Cheers

 

[Nathan]

I'm not sure what the difference between a dry sump and a wet sump is. I am assuming a dry sump means the oil is not stored in the motor. But then if thats the case then what is the difference between the normal oiling system and a wet sump. But yeah I am not sure.

But the big question is if you run a dry sump can you in fact lower the motor and transmission? When I got my first porsche I was very impressed with the dry sump system and how the motor was at the lowest point in the car.

 

[John W]

I'm not sure what the difference between a dry sump and a wet sump is. I am assuming a dry sump means the oil is not stored in the motor. But then if thats the case then what is the difference between the normal oiling system and a wet sump. But yeah I am not sure.

As you say, the oil os not stored in the 'sump' in a dry sump setup.
Instead a scavenge pump is used to - well - scavenge the oil from the dry sump pan
This scavenge pump pumps the oil to a remote oil tank.
A second pump is normally used to feed the oil to the engine. In some setups this is the standard pump but with its input pickup pipe replaced with one that takes oil from the remote oil tank. Other arrangements use an external pump and feed the oil in through the oil filter plate (filter may be mounted remotely as a result).

I would have a look at the aviaid.com web site, as there are some good descriptions of how the system works in most configurations, but they do differ depending on what engine, and what application.

[/QUOTE]
But the big question is if you run a dry sump can you in fact lower the motor and transmission? When I got my first porsche I was very impressed with the dry sump system and how the motor was at the lowest point in the car.[/QUOTE]

Well the Porsche is a good example of the setup. You will no doubt be familiar with the large tank mounted in the right rear wing.
Onb a small block the dry sump can be significantly shallower than a wet sump, so yes, you can mount the engine lower. Just how low though is determined mainly by the size of the flywheel/bellhousing, and to get the driveshafts set at a neutral angle.

The main advantages of dry sumping are:
- shallower sump, allowing better engine placement,
- larger oil capacity, meaning better oil life / temperature control
- no oil surging / pressure problems (if a proper tank is used...)
- in the case of lemans, being able to meet requirement to run for 24hrs without topping up oil

To be honest I'm not sure dry sumping is required for road use, unless you see high oil temperatures in normal road use. For racing though, if you can afford it and have room for all the bits like the pump, tank, remote filter etc, it is well worth the money.

Hope that is of some help.
Cheers,
John (dry sumped 427 side oiler)

 

[Ron Earp]

Definitly do one if you like, but bear in mind there are thousands and thousands of wet sumped race cars running every weekend all over the US. And the World. If you get a nice road race pan (Canton, and many others some mentioned), good pickup, you'll be fine for whatever you can dream up. Worried - add an Accusump for some added insurance and you'll be good to go.

Now, if you are super critical of engine placement then you could use a dry sump and get the motor lower in the chassis. But I don't think you'll be able to take real advantage of it in a 40 due to your transaxle limitations, and chassis limitations.

R

 

[Strobe]

Thanks Ian et al for the response.............never really twigged about the moment of inertia of the car. Poor show considering my WRX selling point is the boxer and engine achieving just that same thing.

Anyways I discussed with my engine builder and he basically told me that there would be no pickup problems running her wet. So thats how she runs.

Point about gearbox and drive configuration is a good one, that plus box will be the determining factor in how low you go.

Steve

 

[chuck smith]

what is the capacity of the Aviad 302 gt40 pan?

 

[Strobe]

on the site

SBF - 289/302, ORIGINAL GT-40 PAN, front sump, 15" long, 6 1/2" deep, 12" wide, 7 qt..

 

[Lynn Larsen]

All,

My Armando's pan which is virtually identical to the Aviad will hold 8 qts below the windage tray. I might put that much in if I were running an endurance which did not allow the addition of oil (see windage discussion below), but it would show 1 qt over full on my dipstick.

Speaking of windage, this is another of the advantages of a dry sump system in addition to those already mentioned. It virtually eliminates windage issues associated with a wet sump system, even if those systems have wipers and windage trays. This translates into more horsepower. Believe it or not, the rods and crank running into flying oil disipate a measurable amount of energy.
Most racers who employ a dry sump system will take great care in dealing with drain back of oil for this reason also, as well as supply and heat issues. The top end will often have its own scavange points and the oil from the crank/rod oiling will be caught by scrapers. The oil from the lifters and cam(s) have been dealt with in numerous clever ways. Lastly, not only will the inner surfaces of the block be deburred, but often they will be coated with a material (the name of which escapes me at the moment, but is generally redish in color) that enhances the drain back of oil down to the scavanger ports.

If you are going to go dry sump, you might as well take it all the way. It will take some planning and research, but it won't add that much to the cost.

Regards,
Lynn

 

[Pat Buckley]

Glyptol, I believe.

 

[Russ Noble]

Don't some of these dry sump systems result in the need for special squirters for wrist pin oiling? At what stage does this become essential?

 

[Jac Mac]

Don't some of these dry sump systems result in the need for special squirters for wrist pin oiling? At what stage does this become essential?

IMSLTHO as soon as you take them out of the box & before fitting to the rods.

You should be drilling your pistons for pin oiling from the oil ring groove for wet or dry sump.

Some high end rod manufacturer,s have a pressure gallery in the beam to feed small end .

Many Jappa's have oil squirters to spray the underside of the piston crown for cooling particularly turbo versions.

Jac Mac

 

[Doug S.]

IMSLTHO as soon as you take them out of the box & before fitting to the rods.

You should be drilling your pistons for pin oiling from the oil ring groove for wet or dry sump.

Jac Mac

For all builds, Jac? Would this be single holes directly above the pin ends or a number of holes around the circumference, as some do for the top compression ring?

Thanks for this tip, BTW. You really are a wealth of information!!!

Doug

 

[Jac Mac]

For all builds, Jac? Would this be single holes directly above the pin ends or a number of holes around the circumference, as some do for the top compression ring?

Thanks for this tip, BTW. You really are a wealth of information!!!

Doug

You have to take the application into account Doug. For example in the 3.25"/3.40" SBF stroker versions where the oil ring is just above or even over the pin bore it is better to drill two holes from the oilring groove to pin bore @ the 10/2 oclock positions ( where these enter the pin bore they can be connected with a small groove to allow oil to get to the top of the pin). Further holes around the ring groove simply allow oil to drain into the crankcase. Try to keep these away from the skirt thrust c/l to avoid the hole itself becoming a stress point for crack propagation.

The holes or 1/2 holes ( they only go as deep as the groove)in the top ring groove are to allow combustion pressure to access the back of the ring and increase radial ring pressure on the cyl wall. Be careful with this one as ring life can be shortened considerably.

Jac Mac

 

[Doug S.]

Floating or press fit?

Thanks, Jac. In my case I am planning on using the 4.125" bore SBF block and will use either a standard stroke 302 crank, or perhaps a 289 crank as I want to build a high reving motor. My question regarding this oiling hole now is whether it matters if the piston pin is a press fit or if it is floating and held in place with a circlip. For this application the oil ring groove should be above the pin bore on the piston, so would I drill at 12:00 and 6:00 (right above the two pin ends) or should I put 2 holes at 10:00 and 2:00 (relative to a single pin end) anyway? I must admit, I am a bit shy about piston pins, as the only engine failure I have ever had on my builds was a piston pin (I should have known that mechanic would drive it like he stole it as he was doing his "test drive"--he denied he did the damage, but....).

I'm hoping to keep compression down to 10.25:1 or so, so I doubt that I will need the holes under the compression ring. I like the idea of making sure the piston pin has adequate oiling, too, and when I do buy the rods for this motor I will use either Ti rods or a high end forged H-beam. I'll certainly look for rods with the pressure gallery in the beam, but if that is not an option I'll perform this adaptation. I'd like for this motor to be capable of 7500 RPM+ and to last for a long time.

Thanks so much for sharing your wisdom, Jac. Those of us who frequent the mechanical section of this forum have learned to look for your posts and take advantage of your advice, for good reason!

Doug

 

[Jac Mac]

Re: Floating or press fit?

Doug the 2.87" stroke setup is a fairly simple one. 289 crank, 5.7 chev rod, pistons to suit 4.125" bore made from 400 chev blanks & valve notches to suit ford head. With 8.210" Block you will require 1.075" pin height for flush deck height. With this short stroke and strong rods etc you may be able to run minimal piston /head clearance which will help prevent detonation which can be a problem at low rpm/high load situations with long rod-pump gas combo's. But I get the feeling that you wont be using the lower half of the tacho all that much!

This combo would dictate that you drill 2 oil holes in the piston @ 10/2 for oiling. Full float your pin's. With the small arc the rod will swing thru all the power loads are going to be on a smaller area, not good for a fixed pin wear wise.

Jac Mac

 

[Doug S.]

Great advice!

Thanks, Jac. Your fluent explanation of the reasons this modification are helpful are well appreciated. I'm sure you are right--the lower half of the tach probably won't see much pointer action, at least if I achieve my goal. I love the sound of a high-winding SBF!!

Cheers, mate!

Doug

 

[Ross Nicol]

The info preceeding this post is very good.I would say you only really need to consider dry sump for racing. You could wreck a very expensive engine if the oil pickup on a wet sump doesn't have oil around it constantly. Modern slick tyres and the terrific corner speeds a GT40 can acheive, generate lateral G forces that push the oil in the pan away from the pick up. So a dry sump on a race car apart from the benefits described previously, give you the secure
knowledge that your expensive engine will not run short of oil. Unless the belt driving the pump comes off that is. The tank holds a lot more oil than a pan too so this helps to keep cooler oil circulating.For those that are unfamiliar with a dry sump system, the pump is a multistage unit.One stage pumps pressure and the others suck oil from the pan,normally through a filter, cooler etc to the tank.I have not had a problem with my dry sump system and don't even think about it while on the track.He said with fingers crossed.
Ross

 

[Russ Noble]

Good info Jac Mac.

I was actually referring to pressure fed squirters similar, I presume, to the Nippon turbo setups. I have seen them on some SBF Nascar dry sump pans on e bay. Pressure fed from the pump and aimed at the pistons. Presumably the lack of large quantities of oil in the sump means less gets to the pin? Is this a real or imaginary problem? There must be a fair bit of oil coming down from the valley and also out the sides of the journals. Maybe the squirters are more important if you also have scavenge in the valley and the drainback areas blocked?

BTW translate IMSLTHO. If it's not too rude. If it is PM.

Cheers

 

[Jac Mac]

I will have to have a snoop around to check on this one Russ. As Nascar still use Flat Tappets( unless there has been a rule change ) those squirters could be lubricating /cooling the pistons ,cam ,or possibly only the LH bank to counteract cornering forces. Most engine builders seal off the drains from the valley to prevent that oil from draining directly onto the crank for windage reasons. Each lifter bore may have a groove machined to pressure lube each individual lobe.

If you still have a pic of the pan in Question Email it & I will have a look.
Cant trust anyone with a camera these day's can you! Ross must be in the " Elite " club at Teretonga, I have never been offered a ride in the Safety Car, did get a reprimand for overtaking it once though.

Jac Mac