blown 87

With all the parts and mods, not sure it can be done for 4 grand.
Plus he has to recoup the time spent on R&D.

GregBBRD

I truthfully have been trying so hard to get Andy's car ready for him to take it to Nevada for the Silver State event that I haven't even added up the parts cost of doing one of these. I spent one Sunday (and a few nights) making a whole pile of little aluminum bits, so Rob could install this "Second Version", to test. We made a few "improvements" over Andy's version and I'm now going back and changing a couple of things on Andys' engine....so he has the "latest and greatest"....before it even runs in the car.

One thing I can tell all of you is that Rob hasn't shown even 1/2 of the pieces involved. Rob didn't think that we should show any of the little details that makes it all function...which is probably a good idea, with "you know who" copying everything he can. I can tell you this: It is a very significant change to how the engine returns oil, breathes, and vents.

It is really nice to be able to run one of these engines at full throttle, for extended periods of time, and not have the heads fill up with oil. The filling of the heads with oil does an amazing list of really bad things to these engines. If the engine doesn't run out of oil and blow hot oily pieces out of the side of the block, it pushes an amazing amount of oil into the intake system....which significant lowers the effective octane of the fuel....which then tries to damage pieces so badly that hot oily pieces fly out of the engine. This is an awful problem and I don't understand why Porsche never solved this issue. Certainly this has been a problem on cars run for extended periods of time at higher rpms. Many of these engines have "expired" on roads, like this.

I have to thank (and curse) at Andy for the opportunity to figure this out. Andy has been as patient and supportive as anyone could/should have been. His requirements for an engine that would function for extended periods of time, and still fit into a street car, made it manditory to figure this problem out. I didn't want to just add an Accusump and pray that the engine had enough oil in the oil pan...while still pushing "cups" of oil into the intake system...making the rod bearings pound out from detonation. That wasn't a solution, but a patch! Certainly a dry sump system would also "mask" the oil problem in the heads and the engine could be vented to the atmosphere, in a race car...but this isn't an option on a street car. I think the last production car that vented oil breathers directly to the ground was built in 1957.
This is a completely "closed" system...no vents are open to the atmosphere.

I'll be making up the pieces required for others to perform this update, after the 11th, so I'll then be able to get an idea of how much this jewelry is going to cost to make. I'll be amazed if we can keep the kit under 4K...it is very complex and requires a lot of pieces/changes. However, it also bolts right on...I made the pieces so that no one will need to do machine work, in their garage. I will need both the valve covers and the oil pan that you are going to use. I made a special fixture to hold the valve covers so that I could do the necessary machining on them, without damaging them. There are pieces inside the valve covers that require careful placement and assembly. While this could be done and then taken apart to paint/powder coat, most will find it better to let me install the pieces and then simply install the valve covers. It is a bit tricky to assemble and make it all work.

Anyone that is currently working on an engine and wants to "move" forward can send me their oil pan to modify. This can be done and the pan can be bolted back on. We are using my pan spacer, oil pick-up spacer, windage trays, and the "stock" early oil pick-up tube, screen, and venturi. If you don't have an "early" oil pickup and pieces, I'd suggest "getting on the stick" and order these pieces from 928 International...or anywhere else you can find them. I'm not sure if Porsche still carries these pieces...I've been buying used pieces from 928 International.

I have not made up a system to work with the "earlier" 4 valve engine or the two valve engines. This will happen...but not immediately. There are also differences in the pieces required for "pre-89" cylinder heads, with the shorter head bolts. You will need to know which heads you own.

Landseer

Wow. Congratulations. What a huge achievement. This is really exceptional. Must feel pretty good to create this solution.

James Bailey

Few people really understand how much Greg Brown knows about engines and 928 engines. Nor do they realize how committed he is to getting it RIGHT ! I liked the story he once shared with me about being part of a 24 hr Daytona race effort.... Team captain commented that they had never FINISHED a 24 hr run after several attempts......Greg's comment ...Then I guess our first objective should be ...Finish the race.

Dave928S

Brilliant ... looking forward to more details on the kit and final price.

john gill

These are the threads that make this forum so interesting and so worth checking from time to time , a massive thanks from those of us that want to race and develop these cars to the potential that I believe they possess .

180 degree turn from the foolishness of dremeling pistons , I know that was an April fools joke YES !

Now with the oiling issues solved , what sort of rpm can we achieve particularly now we have available the custom cams From Mike S and Lizard ?

Lizard928

That all depends on your bottom end bits John, I would love to see a 928 with the bits needed to see 8k rpm. I think it would make amazing power with the right intake.

john gill

Ok let me be more specific ,

GT heads , 87 conrods (944 forged and shot peened) balanced assembly, high compression pistons (85 86 US with cutouts machined to suit the stock heads) ?

Thinking out loud here actually I am being selfish here that is my current project with your cams colin.

Lizard928

What conn rod bolts are you using. Personally I wouldnt spin (ESP NA), a stock part bottom end higher than 6700RPM. The forces go up and it is too likely that you will snap a conn rod or bolt.

John Veninger

Very nice

puyi

Hi,

Seems very interesting and first of all, beautiful stuff made on that engine.

But! Yes I would like to identify what is really a new functionnality of the system and what is, IMHO, not really necessary.

The fact is, that 928 engine suffers, on Hi revs, from big oil consumption and then subsequently, as engine finally miss oil, it breaks.So this system prevents leakage of oil and more importantly, the extended in the housing where it is useful.

If I understand correctly, the external pump is only there to recover the excess oil in the cylinder heads inherent in this engine ... one of the crucial issues of oil consumption. Indeed, the vent of engine cylinder heads, led this excess oil directly into the intake system, which also plans, at high revs, to set up a sort of siffon of excess oil and greatly increases the oil consumption by the admission! So this system is a good answer to solve the problem.

Nevertheless, I ask myself the behavior of the external pump in that it is not constantly fed with oil, in fact, at low speed, consumption of oil is non-existent because the pressure in the cylinder head is within reasonable standards.

Also, are added a set of item, such as windage trays, pan spacers, etc. ... Are we sure that these elements provide a positive answer to the problem of oil flow of this engine. Are They necessary for the new solution. IMHO, it was a backdoor to circumvent the problem, but did not solve the problem. Insofar as this engine wouldnot consume oil due to cylinder heads vents, is it really necessary to include them? In fact, with its full of oil, there would be no problem feeding the oil pump house and thus resolve the problem of oil foaming.

Is not mentioned one solution, albeit partial, but having had some success toward Weissach, was the limitation of oil pressure in the cylinder heads and increase the speed with 944S valves ? In fact, this system ensures sufficient lubrication of the cylinder heads and pushes for sure the point of excess oil.

Thanks for the développement of such system

Best

Puyi

GregBBRD

It would be great to be in a position to develop pieces and then test every little piece, on the dyno separately, and then together on a one with one basis, but that is not possible here. I need to survive and pay my bills. As it is, I've got about 200 hours of work on this one modification, that will never get billed out. This makes projects like this a real loser, in terms of dollars gained. I do this stuff to improve the "breed" and because I love these engines and cars.

The windage trays and pan spacer we developed to keep the oil away from the crankshaft and to move the oil as far away from the crankshaft as possible, in a stock chassis. These pieces have been proven to help, in earlier engines. They might not be needed with this pumping system, but they were already there and working, so we left them. Again, it would be fun to be independantly wealthy and just "invent and test things" all the time...but that is not the case. I do have to make some assumptions to make projects like this remotely feasible.

I considered (at length) just restricting the oil to the head, like Porsche did, with the 944S models. There's a whole list of reasons I chose not to do this. Here's the quick logic:

1. Porsche certainly had the pieces from the 944S at the same time they were working on the late 928 engines. They have dynos and the ability to test everything. They had to know that the 928 engine "packed" oil into the cylinder heads, but chose not to install these restrictors.
2. 944S models turn rpms very quickly and turn more rpms than 928s do, in general. This will provide more oil pressure and volume to the heads, continually.
3. 944S models have a really nasty history of ripping the chain tensioner off of the head and destroying everything...even though the design is almost exactly the same as the 928 application.
4. The lower oil flow could be the cause of this problem.
5. The 968 models "reverted" to the "928 oil" delivery to the heads. Why?

I chose to not restrict the oil flow, but to remove the excess oil. Figured I couldn't hurt things.

GregBBRD

Cross drill the crank and use some specific designed Carrillos.

8,000 is easy.

James Bailey

I have wondered about the wear seen on many of the GT cams and if that was one reason to not restrict oil flow to the heads?? Like you said an S-4 idling down the highway at 70 MPH is not spinning like a 944s but didnt they fit the 968 with 6 speeds /overdrive which too would have lowered the cruise RPM....

Lizard928

Jim,
The GT cars spin faster for more time, this makes it actually easier on the cams.
On the GTs I think it was too soft of springs.