HIGHWAYMAN: Bringing the Devore 928 back from the dead
#257
Hi Rich,
That's what I get for posting after a bottle of Zin and glass of Irish Whiskey...
I should have look for a picture from the rear, it's easier to tell the difference.
__________________
George
90 S4 Grand Prix White (Murf #5)
94 GTS 5-Speed Midnight Blue
06 Cayenne S Havanna/Sand Beige (PASM)
http://928.jorj7.com
That's what I get for posting after a bottle of Zin and glass of Irish Whiskey...
I should have look for a picture from the rear, it's easier to tell the difference.
__________________
George
90 S4 Grand Prix White (Murf #5)
94 GTS 5-Speed Midnight Blue
06 Cayenne S Havanna/Sand Beige (PASM)
http://928.jorj7.com
#258
Trans Gaskets
The gaskets that come in the kit 928 International sells basically allow you to reseal the entire transmission, but it wasn't really necessary to do so on this box seeing as it's in such good shape.
Even though the Diff cover was machined flat, there is still no guarantee that the case itself is flat....meaning there could still potentially be leaks.
I have one rule that I use that has saved me from leaks on my Porsches. First of all, Porsches are notorious leakers IMHO. If they aren't leaking, chances are they have no oil
I hate leaks, and have more or less eliminated them by using Curil T on all gasket surfaces. If you haven't used Curil T before (it is a 911 thing), GET SOME. It's not an RTV or gasket maker. It's a non hardening temperature resistant sealer that is excellent for preventing leaks.
As a rule, I use Curil T on ALL paper gaskets and on the sides of rubber seals (rear mains, front mains, cam seals, balance shaft seals, etc). It has eliminated 100% of the leaks it 's placed on, and needs the TINIEST smear of it to do the trick.
Then I resealed the top cover plate, same story - paper gasket and some Curil T.
Lastly, I cleaned ever spot of grease out of the stub axle cups.
A word about leaky and loose CVs is in order.
1. There is no good reason to have CV grease in the stub axle cups. In fact, many new CV boot kits come with a blind cover plate which keeps the grease inside the CV, and not inside the stub axle cups.
2. CV bolt threads need to be cleaned with carb cleaner and be completely greaseless. This also applies to the threaded holes in the stub axle!
3. The tiniest smear of CV grease on the mating surface of the stub axle will sometimes cause the gasket to leak later.
Lots of Porsche owners wonder why their CV bolts are constantly loose and resort to drilling them and safety wiring them. IT'S BECAUSE THE THREADS ARE COVERED IN CV JOINT GREASE which makes them easy to loosen themselves!!!!
Keep the CV grease inside the CV and your bolts will always remain tight.
Even though the Diff cover was machined flat, there is still no guarantee that the case itself is flat....meaning there could still potentially be leaks.
I have one rule that I use that has saved me from leaks on my Porsches. First of all, Porsches are notorious leakers IMHO. If they aren't leaking, chances are they have no oil
I hate leaks, and have more or less eliminated them by using Curil T on all gasket surfaces. If you haven't used Curil T before (it is a 911 thing), GET SOME. It's not an RTV or gasket maker. It's a non hardening temperature resistant sealer that is excellent for preventing leaks.
As a rule, I use Curil T on ALL paper gaskets and on the sides of rubber seals (rear mains, front mains, cam seals, balance shaft seals, etc). It has eliminated 100% of the leaks it 's placed on, and needs the TINIEST smear of it to do the trick.
Then I resealed the top cover plate, same story - paper gasket and some Curil T.
Lastly, I cleaned ever spot of grease out of the stub axle cups.
A word about leaky and loose CVs is in order.
1. There is no good reason to have CV grease in the stub axle cups. In fact, many new CV boot kits come with a blind cover plate which keeps the grease inside the CV, and not inside the stub axle cups.
2. CV bolt threads need to be cleaned with carb cleaner and be completely greaseless. This also applies to the threaded holes in the stub axle!
3. The tiniest smear of CV grease on the mating surface of the stub axle will sometimes cause the gasket to leak later.
Lots of Porsche owners wonder why their CV bolts are constantly loose and resort to drilling them and safety wiring them. IT'S BECAUSE THE THREADS ARE COVERED IN CV JOINT GREASE which makes them easy to loosen themselves!!!!
Keep the CV grease inside the CV and your bolts will always remain tight.
#260
Nah, the horizontally opposed 6 is one of the smoothest engine designs ever. The problem with the 911 engine is that it uses a lot of gasketless mating surfaces that require the perfect combination of flatness and sealant integrity to stay leak free.....
Also the 944 / 951 engines are leakers and they are basically 1/2 of a 928 engine with some extra bits. I have a 951 now and it has needed balance shaft seals and a front main seal among other things and it doesn't even have that high miles.
Plus, did I mention Curil T smells nice???? LOL
Also the 944 / 951 engines are leakers and they are basically 1/2 of a 928 engine with some extra bits. I have a 951 now and it has needed balance shaft seals and a front main seal among other things and it doesn't even have that high miles.
Plus, did I mention Curil T smells nice???? LOL
#262
Adam, I had Fuel Safe mount my pump inside the fuel cell in the sump. They build door flaps around it and do a great job. The end result is less weight (no surge tank needed) and a simpler install.
After we got it back, we were very curious as to how low we could run our fuel tank and still not surge on or after corners. I got it down to less than a half-gallon at RA and chickened out, afraid if I didn't come in this lap I might not make another 4 miles on what I had. Point is: all the pickup surge problems we had been having were solved. I could run scary low on fuel and not ever feel it - wouldn't have known if I wasnt watching the gauge.
After we got it back, we were very curious as to how low we could run our fuel tank and still not surge on or after corners. I got it down to less than a half-gallon at RA and chickened out, afraid if I didn't come in this lap I might not make another 4 miles on what I had. Point is: all the pickup surge problems we had been having were solved. I could run scary low on fuel and not ever feel it - wouldn't have known if I wasnt watching the gauge.
#263
I might just do that, Carl! I'll run it like this for the first bit and see how we feel.
I also wanted to bump the capacity a bit because Joseph said I would not have enough fuel for the longer sprint races with 17 gallons. I still won't have enough at 18 gallons with the surge tank, but it's somewhat better.
I also wanted to bump the capacity a bit because Joseph said I would not have enough fuel for the longer sprint races with 17 gallons. I still won't have enough at 18 gallons with the surge tank, but it's somewhat better.
#264
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Joined: Oct 2001
Posts: 20,506
Likes: 549
From: Bend, Oregon
Knowing the need for a separate "firewall" panel, I wonder if that surge tank, exposed as it is in the cockpit, would pass tech.
Also, if you are allowed to keep the surge tank, you'll want to plumb the return line back into the top of the main cell rather than back to the small pump suction as it shows in your picture. The way you have it now, there's no way to purge air/vapor from the top of the surge tank in service.
Also, if you are allowed to keep the surge tank, you'll want to plumb the return line back into the top of the main cell rather than back to the small pump suction as it shows in your picture. The way you have it now, there's no way to purge air/vapor from the top of the surge tank in service.
#265
Dr bob,
I will take a pic later on of what the firewall looks like. It basically covers the entire cargo area of the 928. You know that luggage protector thing that is in the street car? It basically has that same silhouette, only in metal.
As to the return line, I cannot take credit for anything with that - my research shows nearly all cars running a surge tank return fuel TO the surge tank rather than to the main cell
http://www.nukeperformance.com/techn...low-chart-faq/
I have ZERO empirical evidence here, but the consensus out there seems to be to return the fuel to the surge tank, in part, to avoid having the surge tank go empty because the main pump can outpump the lift pump.
I'd like to hear further opinions on this...you make a great point!
I will take a pic later on of what the firewall looks like. It basically covers the entire cargo area of the 928. You know that luggage protector thing that is in the street car? It basically has that same silhouette, only in metal.
As to the return line, I cannot take credit for anything with that - my research shows nearly all cars running a surge tank return fuel TO the surge tank rather than to the main cell
http://www.nukeperformance.com/techn...low-chart-faq/
I have ZERO empirical evidence here, but the consensus out there seems to be to return the fuel to the surge tank, in part, to avoid having the surge tank go empty because the main pump can outpump the lift pump.
I'd like to hear further opinions on this...you make a great point!
#266
I plumb the return to the surge tank but vent the top of the surge to the top of the main cell. That way the surge self purges and excess fuel can get back to the main tank. Helps keep temps down the main cell needs another vent so it can pull in air.
#268
Jim,
What do you think about adding the PINK line shown in the drawing. It is not a vent per se, but would be more of an equalizer. Rout the top of the surge tank to the extra pickup, 8AN
Thoughts?
Vent goes straight overboard so if I do a Y fitting on the vent line, I would need a check valve to prevent pressurized fuel from the surge tank going overboard.
What do you think about adding the PINK line shown in the drawing. It is not a vent per se, but would be more of an equalizer. Rout the top of the surge tank to the extra pickup, 8AN
Thoughts?
Vent goes straight overboard so if I do a Y fitting on the vent line, I would need a check valve to prevent pressurized fuel from the surge tank going overboard.
#269
http://www.nukeperformance.com/wp-co...tinternal1.jpg
We're re-writing rules on surge tanks this year, but if you keep it behind the rear firewall, you're covered.
We're re-writing rules on surge tanks this year, but if you keep it behind the rear firewall, you're covered.
#270
http://www.nukeperformance.com/wp-co...tinternal1.jpg
We're re-writing rules on surge tanks this year, but if you keep it behind the rear firewall, you're covered.
We're re-writing rules on surge tanks this year, but if you keep it behind the rear firewall, you're covered.
Sweet, thanks!