We have some experience with rear main seal issues on our TR4 race motor. When
we purchased our car, all of the cranks that were included had already been
machined and the scroll removed. We have been able seal the engines
successfully with careful preparation using these cranks and we have been happy
with the results. Here is what we learned:
1. The Revington Seal Kit does work very well when it is installed properly.
It is good product.
2. There are a lot of cranks floating around that had the scroll removed, but
they were not machined to the correct size for the seal kit. We have found
some that have been machined too small and one that was too large. Too large
was just as big a problem, because the seal could not close all the way around
the crank causing a leak with the oil pressures that we run.
3. The aluminum seal housings are often not installed and sealed correctly.
The problem is further compounded by the felt seal not being completely sealed
when the rear main bearing cap is installed. We use 1 inch pieces of the felt
soaked in Permatex Aviation Sealer and pack them in tight. It is messy, but
seams to work well.
4. Measure your crank seal surface very carefully. If it is too small or too
large, the seal will not work correctly. Both issues can be corrected. Have a
good machine shop read the instructions and help you get the crank prepped per
the instructions that come with the seal kit.
5. Make sure that the machine shop leaves the correct radius corner when they
machine the scroll off.
6. Follow the instructions that Revington includes in his kit to the letter,
and the seal will work great in racing applications.
7. I will only use replacement seals for our housings that are purchased
directly from Revington TR. I have been told that another vendor tried to have
some produced and they may not be the correct size and specification for the
Revington housing. Going to Revington TR for the replacements solves that
issue.
8. Choose the sealant that you use for the housing very carefully. We have
had very good success with Hylomar. There may be other good choices but that
has worked for us.
Hope some of this helps and best of luck getting the motor sealed up.
Paul Ricco
TR4 Blue #4
Sent from my iPad
> On Jan 21, 2017, at 9:43 AM, Jack Wheeler via Fot <fot at autox.team.net>
> wrote:
>
> Before the Viton seal became available, I used a couple of different
> approaches to keeping the crankcase sealed at 7,000 RPM's, both involved
> machining off the scrolling from the rear of the crankshaft. The first was
> to use a rope seal, like the E-Type Jaguar. I took the dimension off the Jag
> crank, then machined the Triumph crank to the same OD. I used the stock
> Triumph aluminum seal to hold the rope seal in place.
>
> My next attempt was a big block Chevy, 2 part neoprene seal. Again, I
> machined the Triumph crank surface where the seal rides to the same OD as the
> Big Block Chevy Crank. Then I machined a two part aluminum retainer, similar
> to the stock Triumph rear seal, but with the inside machined to hold the
> Chevy seal in place. I think there was a kit available at one time, were you
> could buy the seal, and the adapter that holds it in place (Moss (?) or
> someone like that had made up the same aluminum adapter that I had, and were
> selling it as a kit). Anyway, this worked pretty well as long as you got the
> Chevy seal well centered around the crankshaft.
>
> You might go to a junk yard (or speed shop) and find out what the dimension
> of the big block Chevy crank is, at the point where the rear seal rides
> against the crank. If your cranks can be machined to this diameter, then see
> if you can find one of the old Moss conversion kits. When I sold my race car
> to Don Marshall (#11 EP TR-4A - Runoffs winner 1990), there were 2 or 3 of
> these seal adapters that went with it. If you can track it down, see if one
> of these seal adapters is available (out of an engine), and could be used as
> a sample to have one machined. Or, you could do like I did. Buy the big
> block Chevy seal, and use it as a template, along with a stock Triumph rear
> seal, to figure the dimensions needed to machine a two part adapter. This
> may seem like a lot of work, but if your cranks are good, it might be cheaper
> than getting a new crank, especially if you have good machining capability
> available.
>
> Good luck, and let me know what you decide.
>
> Jack
>
>
> From: Tony Drews via Fot <fot at autox.team.net>
> To: Joe Boruch <jaboruch at netzero.net>; fot at autox.team.net
> Sent: Saturday, January 21, 2017 3:12 AM
> Subject: Re: [Fot] TR3/4 Rear Main Seal
>
> I did get the message but don't have any alternate suggestions for
> rear seal if the crank is machined for the earlier seal kits.
>
> - Tony Drews
>
> At 06:57 PM 1/20/2017, Joe Boruch via Fot wrote:
> >Not sure if this went thru before, since I did not receive it in my
> >inbox and did not receive any replies. Sorry for the duplication,
> >if it went out previously.
> >
> >The recent discussion of the valve cover gasket reminded me to ask
> >about TR3/4 rear main seals. I know that the new improved Viton
> >seals are make to fit cranks that the scroll surface has not been
> >machined. All my cranks have been machined to fit the earlier seal
> >kits. Is there an upgraded seal kit to fit machined cranks or would
> >there even be any advantage to using the new seal? Joe(B)
> >
> >
> >fot at autox.team.net
> >
> >http://www.fot-racing.com
> >
> >Donate: http://www.team.net/donate.html
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>
>
>
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