924Board.org

[MikeJinCO]

My fuel dizzy (a -005 model) on a '77 so it is probably a replacement is seeping fuel. I've done searches and appears we have gone from NEVER take it apart to careful rebuilds. The sealant between the halves has ranged fro Permatex Indian Head Shellac(928 rebuild) to Permatex aviation Form A Gasket to wheel bearing grease. Has a consensus of the best sealant to be used ever been made. Has anyone come up with a list of the right O-rings, to use? I live out in the boonies so parts have to be ordered it. The small ones(8mmx2mm)on the piston are available, the larger ones (14 mmx2mm) I can't find. Are there any others? I found replacement dizzy's at something like jaytranco(google bosch fuel dizzy) and they have replacements for $150 plus a $100 core, does anyone know anything about these guys?

The car wasn't running when I got it and got it running(no test drive) by fixing air boots and vac lines, the new gasket materials work fairly well. It appears that the T-T switch might be bad and haven't gotten my pressure guages yet.

Also which fuel accumulator should be used with the -005 dizzy?

Sorry about the multiple questions, but it is not a simple problem.
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Mike


'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)

[bnoon]

http://www.specialtauto.com/porsche-parts/index.html they have the o-rings we need. I'll be emailing them shortly once I take mine back apart to find out what went wrong in my rebuild. I used a Viton o-ring set from Harbor Freight and may have had issues with them. I will check and report back in my dizzy thread that's two down from yours right now.

Any brand gasket shellac will put it back together properly. I wouldn't use silicone gasket maker because even in the thinnest of coating it could easily overflow into one of the tiny fuel ports. I used Lion brand shellac and it worked well sealing the stock gasket back between the two halves. Grease is just plain wrong.
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'80 924 Turbo - SOLD!
1986 Porsche 944 Turbo - SOLD!
Porscheless

[MikeJinCO]

Sorry about the misinformation. I used the silicone gasketmaker on the air boots and it seems to have worked well there. Let it dry for 24 hrs, before installing boots. I bought new boots just in case.
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Mike


'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)

[dpw928]

[MikeJinCO]

I've got nothing against grease myself as it would seal any surface flaws while letting the mating surfaces seal, what I found interesting was your comment about using a 4" scraper to check flatness. I had been considering getting some fine emery paper and polishing the two surfaces on a piece of glass using the figure 8 method we used to use on the valves for large piston type air compressors(100+hp size). On a compressor the two valve surfaces had to seal perfectly or the compressor would operate very poorly as air leaked out past the valves. the Using the scraper would would clean it well and help check it first.

Back in the old days I helped on a Can-AM Lola T-163 that used the Lucas Mechanical injection at 120psi. You let Kinsler take those apart for rework, the pumps were small mechanical gear pumps that had to drag in the case in order to generate enough pressure with gas. I never saw the inside of a fuel dizzy.
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Mike


'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)

[dpw928]

The scrapers are available from just about anywhere they sell ceramic tile. They are used for cleaning the concrete floors prior to setting tile. The Marshalltown brand would be best for this application as they are a harder steel and hold their edge better. They also make an 8" razor blade but that may be overkill in this situation.

Dennis
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81 931 5 sp
78 928 5 sp Silver
78 928 AT Euro Black

[bnoon]

I didn't have to use a scraper of any kind, both sides were clean with no gasket material bits on either half. The gasket material was very thin rubber type and left no residue. This is on an 80 931 with 67,000 miles on it.

Typically grease is used in older gaskets to get the gasket material to swell up, also soaking in gas does the same thing. Other gaskets require a seal material to be applied like a spray. Gasket shellac is also an old time method of resealing/repairing old gaskets or helping new ones seal. To me, grease just never makes sense because it's never in a cured state and can easily be washed away with solvent or constant water spray.
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'80 924 Turbo - SOLD!
1986 Porsche 944 Turbo - SOLD!
Porscheless

[dpw928]

The gasket on the 928 and non turbo 924's are stamped steel. Wish Bosch had used the rubber gaskets on all of the distributors.

Dennis
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81 931 5 sp
78 928 5 sp Silver
78 928 AT Euro Black