Hello all,
I've tried searching for this question, but haven't found anything definitive. Though its still a ways off, I am hoping to add the ol' RX-7 oil cooler up front, complete with a custom fiberglass valence on this '73 1.7. In the meantime, while I've got the motor sitting here in the driveway, I wanted to switch to the heavy-duty oil pump. I have heard this is a good idea with an oil cooler mounted a ways from the pump. I'll be using the sandwich adapter and keeping the stock cooler as well. My question is mostly pertaining to the relief valve inside the motor. Do you have to replace it if you use the type I pump? Will it dramatically increase oil pressure if you don't? Any help would be appreciated. Thanks!

From my personal experience I would suggest running a minimum of:

* HD springs in the relief valve system
* Disabling the bypass in the filter stand
* Use a thermostatic bypass sandwich adapter
* 30 mm pump

That being said I'll be running the CB Performance 2 stage dry sump pump in mine.

-Aaron

Thanks Aaron!
I guess I should have clarified the reason behind this too. The car will need to do 14 hours at Sebring (Chumpcar). So, this is why we're putting the cooler up front , plus coolness/dorkiness factor, depending on your own opinions. For a stock 1.7 doing that much track time, if it lasts, is a HD pump even necessary then? The oil cooler is not optional - the heat being generated for that long means its a prerequisite for us. I'll keep the rest of the suggestions in mind! Thanks again.

Yup. A 27mm is enough to do the job, but they are all about the same price. Don't think you need more than a 30mm pump. Be sure to block off that bypass on the oil filter stand or you'll bleed all your pressure to the cooler off.

if you block the filter relief valve, be sure to get a high pressure filter can or buy a filter with an internal relief valve. the HP1 filter has a 22 psi valve. the stock relief ball valve at the filter opens at around 10 psi or so.

lesser filter cans can rupture if no relief is used specially if you rev it whilest cold.

since space is at a premium for the stock filter and that space is reduced with a sandwhich adaptor, you may want to use a remote filter mount, this will allow use of a much larger filter, for less pressure drop and less chance of a rupture.

Personally for your app I'd use the 30mm pump (tapped and plugged) with a steel full flow cover, ditch the stock filter stand for a remote filter adapter and use a quality temp bypass. The RX-7 cooler internal temp bypass in stock form may be acceptable for a T4, but you would need to research this. Block off the stock filter mount location and tap into the upper galley plug for return (in a FF app you do not need to tap and plug the bottom galley plug) you must tap and plug the flywheel oil galley plugs.

Try to avoid hard 90* fittings where possible and to use a FF cover you will need to modify the one engine mount for clearance. You will have to prime (bleed) the system before initial start-up.

A pic of the modified mount:

and use longer studs in the case

Yikes,
This is a little more involved than I was thinking. Can any of the tapping be done with the motor together? Wouldn't that introduce metal shavings? My other problem with the full-flow approach and removing the stock cooler means that I would have to think of some kind of fan setup if I wanted to drive it on the street afterwards, correct? This car is a little bit of a confusion, I'll be honest as its going to see some racing but hopefully survive so I can enjoy some regular driving from time to time.

Your stock 1.7 is overheating without a cooler? Have you checked the tins?

No, no. It ran fine when I had the motor in it. But its going to be running (hopefully) 14 hours at Sebring in August with Chumpcar. I'm sure it won't be the only one of my concerns, but its my biggest right now. I just am interested in putting it up front.. well, just 'cause.

Yes, very carefully using a vacuum and greasing the tap and bit, cut a small amount clean and re-grease, repeat.
You still use the stock cooler, it's just the filter stand you are removing if you go this route.

I fail to see where you're getting the idea that it's gonna overheat. I think not. Back in the day, stock 914s were driven all day on long trips here on the left coast, and overheating wasn't an issue then.

The Cap'n

Hmmm. I do trust you guys, I promise. But tooling along the highway at 55-65 and trying to push a car hard for 14 hrs are different. I'll definitely do some more contemplating first. I just have a feeling that this might be a worthy investment before finding out the hard way. Again, all opinions welcome.

It's only going to overheat if there is something wrong with it.

Make sure the cooler and tins aren't packed with crud ( they might be packed with leaves and other debris ) and tune it up and you should be fine.

stock 1.7's or 2.0 can run too hot with extended driving at high rpm's Pushing 4000 rpm can cause the oil to get too hot specially in a hot climate, or pulling a heavy load or up hills. The cooling system is marginal , push it hard, or spin it faster and it can cause problems.

For a simple fix, try a remote cooler, in addition to the stock cooler, you can use a sandwihich adaptor at the oil filter, and then install a shorter filter to the adaptor (hoses will enter/exit the side of the sandwhich adaptor) you can then mount a remote cooler from those hoses, some sandwhich adaptors have a thermostat built in, or get a remote thermostat. You dont want to skip the thermostat, as too cold oil is not good either.
an other option is to run a remote filter also, using an adaptor on stock filter mount, that has simply an inlet and outlet for hoses, you then mount a remote filter, then a thermostat, then the cooler. The nice thing about a remote filter is you wont be limited to a small filter can. Bigger filters are better as they can flow better and than means less likelyhood of the filter going into bypass mode, and your oil not all getting filtered.

with a good remote cooler you can keep the temps down, and that is a good thing, 180F should be a nice target temp for the sump oil, although under 200F is still very nice temp.
for good cooling get the biggest cooler you can fit, mounted in cool air flow is best, but that usually means the front bumper area, you may not want to cut the car for that.
You can get some cooling however with a flat cooler mounted near the tranny under the trunk floor use an electric fan, but the air under the car is pretty warm, so you may still see some temp spikes, but you will be much better off than stock.

I have mounted a Empi 72 plate cooler under there, you might even be able to fit the 96 plate one (it is about a foot on each side, and about an inch thick, fan addes another couple inches to thickness.) If you have a Bursch type exhaust rather than a stock mufler you will have more room to mount the cooler

but the optimal place is in the cold air stream at the front of the car.

these cars tend to run even hotter than when new becuase of the oxygenated fuels now mandated. Smaller tires also up the engine rpms, and that means more heat too.

Yeah, this is what I'm thinking. Front mounted cooler with remote oil filter. My first question was whether a) even needed the 30mm oil pump and b) with the pump what changes I need to make, as in oil pressure relief valve springs. If I need to change the valve springs, would this involve disassembling the engine?

Okay, back to the original question... would the relief valve springs need to be changed if running a 30mm pump? Can this be done without tearing the engine apart? From this page http://www.ephotomotion.com/914engine/page12.html it appears so. Since I will already be changing the pushrod tube seals, that might be a good time, no?

Need, no. Want to, yes. It's easy even with the motor in the car.

Okay, now we're getting somewhere! Do I "want" to change both the primary and secondary then? Any specific vendor you would suggest? I'd assume Gene Berg.

OR, am I finally starting to make sense of this? Rather than changing the valves/springs, I could just use a Gene Berg Oil Pump Relief Cover, no? Geez, NOW I get it

Those both solve different problems.

The GB cover prevents too much pressure from entering the lines. This can help save expensive parts like oil coolers, fittings, etc... I've never run one even on my old drag bug that spun to 7500 rpm. Just be careful when the oil is cold.


The Weltmeister pistons (or HD springs) allow the engine to run higher oil pressure internally. Good for higher rpm applications and to remedy worn out bearings and the like - anything that would cause lower than desired oil pressure.

I always highly recommend not mounting coolers up front with wet sump engines. The only oil pumps I have found to be effective for this volume wise are the Pauter wet sump pumps( that one is now NLA) and the revmaster pump with 38mm gears.

I always have better luck with a super efficient cooler mounted closer to the engine, using the least amount of hose possible. Of course, no opinion on this topic will be the same.

High pressure oul relief pistons and other gadgets are band aids that often cause more issues. We have one 640HP engine and even it uses stock oil ores sure relief components.

I disagree with this.
If the oil isn't getting to at least 210 there's no need for additional cooling capacity.
Its pretty hard to get the oil up to 210 in a stock 1.7L.

Okay, just wanted to say thanks to everyone for the thoughts and replies. Clearly this is an issue that has people pretty divided, but I think thats a good thing. It means people are thinking and using logic - this works well for me! After reading back though all of the responses, I'm going to put a game plan together before buying any parts. I'll be using a little of everyone's advice, I think. My biggest problem right now is visualizing what it will look like, and understand what each piece is. I don't know my way around these motors yet, so I don't know what some of the terms are - "full flow", where the bypasses are, the plugs, etc. Just a little more work than what I thought originally. Chris - just curious, you don't think this car will run over 210 if pushing it hard on long straights at Sebring? And aaron, if the HD springs allow higher pressure inside the engine, is this what I want, since I'll already be adding a pump that will be increasing pressure? I guess I just don't understand their purpose.

I'm newer to air cooled engines mostly I do LARGE cummins diesels. As a genral rule too much oil pressure is a waste of horse power. 10 pounds per thousand rpms is good to go in the chevy race world (40 lbs at 4000rpm). Otherwise all the oil is getting hotter because it is being pushed through the relief valves. This is call oil shear and when a valve is left part open or a lift cylinder is bypassing it gets HOT. Just my 0.02 Gordon

Equip the engine with proper instrumentation and place senders in the smart locations. Monitor CHT under the spark plugs and OT in the oil sump. The oil in these engines isn't "hot" till 225*. Even if you hit a 225F oil temp and the oil you are using has enough high temperature viscosity to maintain oil pressure- run it.

The SAE standard for high level viscosity is set at 212F, not all oils that are a 40XX grade or 50xx grade at 212F are still that same grade at 225F, some fall like a ton of bricks at 215F, others love temp and will maintain stable oil pressure clear past 240F and some clear to 300* in our exotic lines. If the oil is a 50 grade at 212, but it drops off to a 30 grade at 240F you will have bigger issues and lower pressures.

The moral of the story is to do what the engine needs and determine that by LISTENING to what it WANTS. This is why you have gauges- lots of up front preventive fixes are simply catalyst for failure, or simply aren't needed and do nothing except complicate the car/ engine and empty your wallet.

Hell, I WANT my engines to run 215-220F oil temps all the time, until that happens the impurities in the oil aren't "cooked off".

Try it out, see what you have and develop a plan based on what you NEED. Sebring has some of the most adverse conditions found in the US during the summer with high heat, 140* track temps and super high humidity while being very near (at) sea level. The main thing that will keep your engine coolest is proper optimization of the tune for these conditions. Better tuning= efficiency; efficiency= cooler running, better running and more fun.

At a little past 210F the oil pressure take a noticable drop off (20W-50 oil)

If you cant push past 210F with the highest load on the hottest day, you probably dont need a extra cooler.

I was hitting 230F or so, with pressure drops. and then added a cooler, and see 180F in normal driving, and peaks near 210F when driving hard on hot days (100F).

If you use big fat hoses and lines to the cooler, front mounted can work, you just need to make sure you dont have to much pressure drop from small hoses and such.

also note that if you see 180F at the sump you can be sure some of the oil got hotter than that for impurity burn off. The oil that just prior to entering the cold sump was at the heads , incontact with very hot head metal, so that oil more than likely exceeded 210F before it hit the cooler sump oil.

That's with the oil you're using.

The Redline oil I used to run in my racecar didn't noticeably drop in viscosity until it reached 230F (measured at the dry sump tank after going through the cooler).
As Jake wrote in the above post, the drop off occurs at different temps for different oil/additive formulations.

I was running thru the desert on the hottest day of the year, pulling grades and saw 245 oil temp .... no pressure drop whatsoever ... Kendall Liquid Titanium 20 - 50 with a quart of Lucas Oil Additive.

I've run my 914 in 6 LeMons races. Half with the stock setup and the other half with an extra oil cooler. I've yet have to run the cooler fan. I can't tell any running temperature difference. I don't think I would go to all the trouble of putting the cooler up front. Seems like a lot of work for very little if any gain.

Click to view attachment

Good luck with Chump cars.

Brad Penn 20w-50 is what I have been useing.

Remember: Cooling the oil won't cool the heads.

This is great stuff guys! I think this will be a valuable thread for all. Again, its interesting to see the very different viewpoints on this matter. I'm glad I asked - I've learned a lot so far. Jake, you're right for sure. I need to start with some gauges. When I had the car running, it had no oil temp or pressure gauges, but the idiot lights never turned on just running up and down the neighborhood. Its certainly on my list of things to do. I've got a taco plate on the way. Now just waiting to find a deal on an oil temp and pressure combo to start. The cylinder temp gauge will follow. For the oil pressure gauge, do you all recommend the 80 psi or 150 psi version? The 150 is a bit cheaper on PP.

Joe, thanks for the info about Le Mons. I was sure that running one of these that hard would require a cooler. Interesting that you don't really see a difference. I'll add that to my considerations.

Thanks again everyone!

i used dakota digital gauges. the are suppose to be very accurate. oil temp, oil pressure, and cyl head temp.

ThePaintedMan PM'ed me on FF oiling, thinking I'm the expert, I'll answer him here. I wouldn't consider myself an authority, although I've installed many systems on type one and 4s. In a quality type 1 build it is an absolute must as they don't even have an oil filter. In a type 4 you can get away with just the type one pump and a blank cover using the existing oil system. That said if I was to add a AM cooler the only way I would do it is with a FF system. I think all-in-one filterpumps are total crap and I'd never use anything but a steel pump cover.

There are many threads on the web about FF oiling, just do a search.
This thread is very good on understanding how the oil system and full flow oiling works:
http://www.thesamba.com/vw/forum/viewtopic...asc&start=0

dont forget the steel pump covers mucs be very thick or have a raised edge around them to give stiffness to the cover. (as the stock Bug cover is) i have run into flat steel covers (no raised edge) about 3/16 inch thick that would bow out as the four bolts were torques down to specification, the bow int eh middle was on the order of .005 inch, That more than the thickness of the pump gasket, talk about potential pressure loss. Be sure your oil pump cover is lapped flat too.

I can wrap my head around FF oiling I think. But I still don't have a definitive answer on whether a stock pump is adequate to get the oil all the way up front, or whether a 30mm pump is necessary. I think Jake said that he believed even a 30mm is inadequate.

What I also don't understand is what to do about the added pressure of a large pump, even in a FF application. FF oiling doesn't do anything to change the pressure inside the motor, correct? So a 30mm pump could up the pressure, which I would have to deal with, correct?

Sorry, I feel like but I'm still very confused.

You don't need a bigger oil pump.
You don't need a front mounted oil cooler.
Both would be a waste of your limited resources.

There's really no need for you to convert to a FF oil pump cover either.
If you feel that you must install an auxillary cooler, a small unit mounted under the trunk, plumbed off a sandwich plate will be sufficient. You won't even need a fan or a thermostat.
If anything, you might want to disable the bypass built into the filter bracket.
Spend your money on instrumentation and tuning the engine so it doesn't run too lean and overheat.

Because you don't seem to want to take the advice of the "experts" on the subject. One who has reinvented what it means to rebuild a T4 motor and the other who is actually doing what your contemplating doing and has shared his results. Sorry... don't mean to sound harsh but, a lot of times people get their head around something and refuse to let go.

Not confusing to me... If Jake told me it probably wasn't needed and Joe told me it made no difference, I'd look elsewhere on where to waste my money. Sounds like slot machines would net you a better return. At least you get free drinks while you're playing.

Eric,
I respect your opinion, along with all of the other gurus you mentioned. I've said multiple times and made it clear that I know its not "necessary" to even have the front mount. I was initially simply looking to see if was feasible. I'm happy to hear that it isn't necessary. I understand its a waste of time. I understand its a waste of money. I am an idiot, I know. Just was curious if its possible and what was necessary. Think I'll just let it be for now. Thanks to everyone for sharing your opinions anyway.

Please do some testing. I myself am not convinced a stock 1.7 won't need some help in the cooling department in an endurance race.

What kind of tires will you be running? What's your suspension setup like?
I ask in order to get an idea of your cornering capabilities.
If you can't run DOT-R tires you won't really be working the engine all that hard.

Greater volume is required to build higher pressure with the same internal clearances and oil viscosity. You won't raise PSI until you add volume. Large systems with big coolers and a lot of sharp bends in the fittings lose volume. Keep the oil system as small and simple as possible.

Chris,
Tires are open, as long as they're DOT legal and treadwear > 190. I'm thinking Falken Azenis. However, this still won't mean we're pulling and kind of hard G's in the corners. We'll probably be running faster through the corners than most of the lead sleds, but nowhere near what many of you guys run. The car right now has 100 lb springs out back (AFAIK) with Konis and a stock front swaybar. I can't imagine doing much more to it without 1) upsetting the balance and 2) getting into the "suspicious" range. Every dollar that the car is valued over $500 (which includes bolt on parts, etc) gets us penalty laps added.

Jake,
Good to know. Again, I'll add that to my notes. Thank you.


-George

Thats what I figured. I doubt you'll ever exceed 1g cornering. That translates to lots of time off throttle and at part throttle, allowing the oil temp to stabilize at a lower temperature.

I've driven very long distances on the highway at high speeds - more likely at greater average throttle setting than you will.

When I ran a 1.7L in ITB in the mid 90's I had Hoosier tires, 19mm front antisway bar, 21mm torsion bars, 140lb rear springs, short R&P - and I'm not sure I needed the small cooler I had.

Yeah, I'm starting to think that we'll be okay as-is. However, I don't want to get caught out, ya know? If I'm wrong, then there will be little we can do at the track to make a change. I think that a front setup, as cool as it is, is probably best for another day... or a six! However, I'll let everyone know what route we do end up going.

SOT, Chris, what other suspension tips could you give me with the setup I already have? Would you recommend 140 lb rear springs to go with just the 19mm sway-bar I already have up front?

140 rear springs would be a good thing. You might find some used from someone making a further upgrade. You should be able to sell the 100s to someone who still has the stock -4 rear springs.
Set your ride height at 5" to the bottom of the rocker panels.
Set rear camber at 2 to 2.5 degrees negative and front camber at minus 1.5-2 degrees.
Run zero toe up front and 1/16" total toe in at the rear. (1/32" difference between the front and rear edges of the wheel, per side measured with the car between parallel strings.)
Start with the anti-sway bar at half stiff and make adjustments based on cornering feel.
If the car is a little loose that's fine. You'll need to plan on being on throttle as you enter the corners. Always make sure you downshift before corner entry so that the engine is above 3500rpm or you won't have enough torque to transfer weight onto the rear tires.
Upshift at 5700. There's no benefit from going higher.

This is what happens if you forget to downshift and try to go into a corner at speed
Click to view attachment

I ran the Azenis with 180lb springs, 21mm torsion bars, and 19mm bar up front - no bar in rear. If you are still running a rear bar that should be OK for rear spring rate. Just for comparison I'm up at 275lb springs now, but on DOT-R tires.

I tend to spring the car and then use anti-sway bar for tuning, where some people use the anti-sway bar as an auxiliary spring.