The FED will need a bit more care. Eastern Creek is tolerant of (relatively) minor leaks during the Wednesday street car meets. The tolerance is less for full race meets. I know one gentleman who was questioned over oil leaks on a HAMBSTR grey, only for it to be revealed as Permatex Aviation Gasket Sealer. It would break my heart to be ready to race only for the scrutineers to be unhappy with the oil leaks. Most of the engine leaks can be cured with some care… or on a bad day with a smoosh of silastic (the Plumbers Creed: do your best, silastic the rest). Not the neatest of finishes, but it will let you continue racing. The rear main is kinda hard to silastic up though.
The grey motor rear main seal is renowned for leaking. The original rope seals (often referred to as a “dog turd”) is no longer available (probably due to an asbestos content). The replacement seals in overhaul kits can be serviceable, but often leak in service. Whilst some of this is the ability of the installer, even experienced old-Holden mechanics struggle with them.
A trick from the lumpy humpy crowd is to use a Fergie tractor seal instead of the aftermarket ones supplied in grey motor overhaul kits. This thread will show what I am learning as I go with using the Fergie seal. Bear with me on this one… I am short on time, and sometimes life overtakes me playing with the FED motor. This may take a little time.
First things first… which seal? All I had to go off was “it’s a Fergie seal… call Wagga Tractors… they will know the one”. To save you some heartache, here is the seal part number:
- Fergie rear main seal part number.jpg (792.97 KiB) Viewed 542 times
- Fergie rear main seal.jpg (574.25 KiB) Viewed 542 times
The seal has what appears to be a graphite centre (like a spark plug lead), a fibre casing and a white Teflon outer coating. Nothing like the asbestos “dog turd” seals. It cuts easily with a knife and does not splinter/fluff out much.
For anyone needing a cross-reference, the seals were also used for the following:
- Cross reference table.png (33.73 KiB) Viewed 542 times
The seal needs a 60 thou aluminium backing strip in order to work properly. With thanks to Rob, I received two strips – one 4.3mm wide and one 5.4mm wide. The 5.4mm wide one is a bit too wide, and sits rather proud of the rear main seal groove (like the image on the left below). The 4.3mm one seats much better (like the image on the right) and is the one I will use.
- Rear main bearing reinforcing strip width.png (2.78 KiB) Viewed 542 times
The strip needs to be bent to a neat half-circle to conform to the seal groove. The ally is fairly soft, but still does not like bending by hand – my attempts to do so delivered a result like the image on the left below. What I really wanted was a neat half-circle like the image on the right. (note this drawing is at right angles to the one above).
- Rear main bearing reinforcing strip.png (7.68 KiB) Viewed 542 times
To get a smooth bend, I made up a forming tool out of some 6.5mm plywood scrap. The seal groove is 2.695” diameter, so I cut the ply 120 thou less than that (2.575” diameter). The forming tool is then rocked back and forth in the groove to gently bend the aluminium, as per the photos below.
- Reinforcing strip installation tool.jpg (1.02 MiB) Viewed 542 times
All jokes about Harv getting his groove on appreciated.
The next step is to cut the strip to the right length, and deburr it. For now I have made the strip just the right length that it fits into the seal groove and is flush with the top edge. I did this by filing it back, putting it in the groove, then putting a straight edge along the top. At first the strip is too long and the straight edge will not sit flat. Keep taking more off until it does. File a little, check a lot.
I’m a bit torn about whether to make the strip sit flush, or slightly under diameter (for now it is flush). As the ally gets warm it will expand, and expand more than the cast iron seal groove. Would hate for it to smoosh out the seal. Undecided yet.
More instalments to come as I get this thing sorted.
