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Very interesting, but i do not understand the oil behavoir during shut down of the engine.
All dry sump systems I have seen come with an internal or external pump that is located below crankshaft level. The consequence is that the oil level is always located below the crankshaft and there is no risk of hydraulic compression at start-up which will damage the engine. So I wonder how you have managed that with the original oil pump that is located at the same level as the crankshaft. Is there a solenoid valve which prevents after stopping the engine that the oil which is in the oil tank does not descend into the engine?
And then how you ensured that the original internal pump of the block is well powered? You mentioned a pre-oiling system, is that what we need to understand, priming the internal pump before starting the engine?
Very interesting, but i do not understand the oil behavoir during shut down of the engine.
All dry sump systems I have seen come with an internal or external pump that is located below crankshaft level. The consequence is that the oil level is always located below the crankshaft and there is no risk of hydraulic compression at start-up which will damage the engine. So I wonder how you have managed that with the original oil pump that is located at the same level as the crankshaft. Is there a solenoid valve which prevents after stopping the engine that the oil which is in the oil tank does not descend into the engine?
And then how you ensured that the original internal pump of the block is well powered? You mentioned a pre-oiling system, is that what we need to understand, priming the internal pump before starting the engine?
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Good questions.
I believe that you will find that the location of the pump has nothing to do with oil filling the crankcase (wet sumping) when a dry sumped engine sits for long periods of time, rather a function of the oil level in the tank. This issue of "wet sumping" a dry sump engine is always about the two oil levels reaching equilibrium.
We will monitor the amount of oil that escapes past the oil pump gears and escapes past the bearings and are prepared to add a check valve if needed.
However, since the level of the dry sump pump is about halfway down the level of the oil tank, the tank will never completely empty into the crankcase..
By simply starting the engine, after long periods of sitting, the oil in the pan should return to the tank within seconds,, while there still being ample oil to provide oil pressure.
The stock oil pump is no longer a pump, but now is simply an idler gear for the timing belt.
There is no pre-oiling system. We will pre-oil the system by removing the belt from the dry sump pump and turn this pump with a drill motor until we get oil pressure.
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
@GregBBRD : Would you be willing to share the source of those clamps? I was looking for something similar a little while ago and didn't make great headway. Those look slick, especially if they come in different sizes.
One of my major objections to the all aluminum 928 Motorsports all aluminum water tank has always been the complete lack of the ability to see what the level of the water in the tank is, without letting the engine cool down completely.
Therefore, I've never used one of these tanks, until now.
Some oil tank design constraints required me to make a modification to the water reservoir, making the use of an aluminum tank, virtually imperative.
Kyle (my son) came up with this: 928 Motorsports water reservoir, modified for external "sight glass".
We will certainly offer this as an "add on" kit, for all those people using the 928 Motorsports water reservoir, who are tired of guessing what their water level is, when the engine is hot.
@GregBBRD : Would you be willing to share the source of those clamps? I was looking for something similar a little while ago and didn't make great headway. Those look slick, especially if they come in different sizes.
Thanks
They do come in various sizes.
It is a product we stock, in the J2 Precision hose part of the business.
(Although after this construction, we are low on inventory.)
If you need pieces quickly, these are made by a company in Arizona named "Axia Alloys".
You can find them online at axiaalloys.com
They make several cool products, mostly for off road vehicles.
One of my major objections to the all aluminum 928 Motorsports all aluminum water tank has always been the complete lack of the ability to see what the level of the water in the tank is, without letting the engine cool down completely.
Therefore, I've never used one of these tanks, until now.
Some oil tank design constraints required me to make a modification to the water reservoir, making the use of an aluminum tank, virtually imperative.
Kyle (my son) came up with this: 928 Motorsports water reservoir, modified for external "sight glass".
We will certainly offer this as an "add on" kit, for all those people using the 928 Motorsports water reservoir, who are tired of guessing what their water level is, when the engine is hot.
Sight glass systems like that have existed for a while. I've always shied away from adding them to my 928MS tank because it introduces additional failure points into the system (welded fittings, threaded fittings, soft hose, clamps, etc). Though it would be nice to be able to see at a glance, with the cooling system being a closed system, the tank having a low fluid level warning light, and it being easy enough to check when checking the oil every month or so, I've never decided it was necessary.
The system also manages its own max level so if you put in too much coolant when cold, it just dumps the excess out the overflow hose then self-regulates to the proper max full when hot level, doesn't it?
How long will the silicone hose remain nice and clear and easy to see the level before needing replacement?
Sight glass systems like that have existed for a while. I've always shied away from adding them to my 928MS tank because it introduces additional failure points into the system (welded fittings, threaded fittings, soft hose, clamps, etc). Though it would be nice to be able to see at a glance, with the cooling system being a closed system, the tank having a low fluid level warning light, and it being easy enough to check when checking the oil every month or so, I've never decided it was necessary.
The system also manages its own max level so if you put in too much coolant when cold, it just dumps the excess out the overflow hose then self-regulates to the proper max full when hot level, doesn't it?
How long will the silicone hose remain nice and clear and easy to see the level before needing replacement?
I've found that with the several racing 928's I've been involved with, coolant level when hot, is something important to monitor, especially in the heat of the desert (Willow Springs, Ca. and Thermal, Ca., for example.)
While coolant level may not be important to you,
I want both myself and my client's mechanics (at Thermal) to be able to monitor this, at a glance.....without waiting hours to check the coolant level.
Granted, if the hose was silicone hose, it would not last, very long.
The water pressure and heat would probably make silicone hose "balloon" quite a bit, the first time it got hot.
Give me a little bit more credit...While certainly not the sharpest stick in the shed, I'm not the dullest, either.
That hose is clear PTFE, rated for 3,000 psi and 500 degrees F. (We tested it to 250 psi.)
And being PTFE, it will not discolor.
While there are potentially failure points, the aluminum fittings are welded into the tank.
And the hose will certainly outlast the aluminum tank.
So the chance of failure of this addition is extremely low.
Looks like a good solution Greg and all your stuff is too -notch and why we buy it.
If I knew how to weld.aluminum, I'd probably get one of the kits for the Spyder that has that tank, but I'd have to take my tank to someone to weld it, which i could do. Not high on my list of 928 projects at the moment as I'm trying to finish the bronze car and need to drop the rear subframe of the Spyder to have the Z06 torque tube rebuilt.
They do come in various sizes.
It is a product we stock, in the J2 Precision hose part of the business.
(Although after this construction, we are low on inventory.)
If you need pieces quickly, these are made by a company in Arizona named "Axia Alloys".
You can find them online at axiaalloys.com
They make several cool products, mostly for off road vehicles.
Haha, that’s clever GB, I know those clamps well. On a UTV they are used the opposite way, big round side mounts to the roll cage and the small end holds whatever you are clamping to the cage! They do make beautiful pieces.
One of two oil coolers for the engine. It's big...holds over 2 quarts of oil, with its' thermostat and hoses from thermostat to cooler.
I'm also using the "cooler" in the radiator as an oil warmer (this engine has a large amount of oil circulating around...without an oil warmer, it would take a long time to get the oil up to temperature. I redesigned a custom inline thermostat so that the oil runs through the radiator until it reaches 185 degrees. The thermostat then closes, shutting off the flow through the radiator (in order to not have the oil heat load transferred to the water.)
It looks like you are working toward the same intake solution that Louie Ott pioneered to get adequate air into the monster motor he built. Louie eventually re-mounted the radiator on an angle to get clearance above it for the air to pass over in the necessary volume. This also allows for the air filter to be mounted in front of the radiator. This area is by nature a cooler, higher pressure area to feed the engine from. I personally can't wait to see what you ultimately build to "Feed your giant"
It's a work in progress.... Intake plenum/chassis support.
For the transmission, we knew that the very old design PSD system would not be appropriate.....way, way to slow for a modern style 928.
So I drew up and "invented" a new limited slip (with the ability to turn the stock GTS transmission oil pump.) The "prototype" is inside this gearbox. Eight total friction disc surfaces and completely adjustable from a 20% limited slip to an 80% limited slip. (lots of options on how much torque it takes for the limited slip to release.)
I installed our custom carbon fiber synchros (made specifically for use in the 928 transmission) and did a few more tricks to help the transmission "live". (Details will follow...to a certain extent.)
In this application, a 928 manual trans will break sooner rather than later, no matter what you do to it. And as a result, the car is already crippled before turning the key for the first time.
Just bite the bullet and fabricate/install a C7 Z06 manual transmission, it's a superior trans in every way. There's no doubt you can do it - and do it right - and you'll never have to worry about it again. It will match and compliment your monster of an engine.
I tried to convince ptumov to do this for his TT since he was running a manual too. However, last I heard, he was going to install an automatic after his manual failed. Twin Turbo Todd has proven for years now that an auto will work for 1,000 rwhp, so ptumov is headed in the right direction, although without a manual which apparently was his first choice.
In this application, a 928 manual trans will break sooner rather than later, no matter what you do to it. And as a result, the car is already crippled before turning the key for the first time.
Just bite the bullet and fabricate/install a C7 Z06 manual transmission, it's a superior trans in every way. There's no doubt you can do it - and do it right - and you'll never have to worry about it again. It will match and compliment your monster of an engine.
I tried to convince ptumov to do this for his TT since he was running a manual too. However, last I heard, he was going to install an automatic after his manual failed. Twin Turbo Todd has proven for years now that an auto will work for 1,000 rwhp, so ptumov is headed in the right direction, although without a manual which apparently was his first choice.
While I do appreciate your expertise in the 928 5 speeds transmission problems, I don't agree with you.
Yes, the '85/'86 transmissions that Tuomo was using definitely have limitations.
However, the later model transmissions found in the GT's and GTS vehicles are much more robust.
And fortunately, I was able to see, first hand (from Mark Anderson's transmissions in his racecar), exactly what the weak links were, when his 928 transmissions did fail. (Not nearly as often as 911 Cup Car transmissions, BTW.)
While you may not be aware, I never hesitate to build custom pieces to fix various issues/limitations which I find, in the 928 vehicles.
Actually, it's's kinda what I do.....
And I've done this, here.
And while I don't believe that we will be able to drag race this transmission, I think it will survive road racing.
And if it doesn't, I've got a couple more "trick pieces" to put inside.
So, for the time being, I think we will leave this Porsche a Porsche...and skip the whole Porchev thing.
02-22-2022, 09:39 AM
