E228 - Comet Dynamo Pinion

clevtrev

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The reason that leaks occur is because the timing chest has not been set correctly. The first part of the assembly should be the dynamo, centralised in its seal. Then the cam, the large idler, and the selective half time pinion. Most tend to fit the dynamo last.
 

TouringGodet

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Thanks, Trev, I'm going to finally install a new timed breather, to replace the one that broke over in England while I was going to the '87 International, plus sizing a new half time pinion, so this advice has perfect timing.
 

ogrilp400

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Two areas have been a right pain in the arse for oil leaks on my Comet. The back of the primary and the Dynamo drive. I have fixed the primary leak but the dynamo drive is proving nearly impossible. I have:- replaced the seal, replaced the seal again, smoothed and polished the pinion seal surface and replaced the seal, returned seal diameter to size, put two seals in there, put two double lipped seals in there, put an o-ring between the seals, gone to great lengths to make sure that the Dynamo shaft is perfectly central in the CC aperture by machining up an adapter to fit very neatly the shaft and the CC hole, fit and secure the dynamo then take out the adapter and fit the seals. Still the oil BUCKETS OUT!

Phelps.
 

timetraveller

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Sorry if this sounds condescending but are you sure that the breather is correctly timed and not blocked? When fitting one of our car alternator kits to a Comet we find that it is not necessary to fit the seal at all, although some people do fit it and feel psychologically more secure. The piece that replaces the dynamo has a sealed for life bearing and the end face is machined flat. The whole thing is a nice fit in the hole for the dynamo. The end of the dynamo replacement is covered in silicon sealing compound and then pushed in until this sealing compound is well 'squished'. The whole lot is left to set after which there is absolutely no leak from that place.
 

ogrilp400

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Yes the breather is correctly timed and unblocked and even so with all the seals in there it would take probably 50 to 80 psi or even more to blow the seals which would show up as the seals turned inside out. I am beginning to wonder if the leak is actually coming from the sealed pinion and not from perhaps the recess being machined too deep and broken through into the timing chest. With all the oil there its difficult to tell.
 

timetraveller

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Well, at least with a Comet you do not have to remove the exhaust pipe to take off the timing cover and it is only a few nuts and bolt to take off the dynamo. Then you can clean it all up and see if daylight is visible around the central hole. It might be a crack you are looking for rather than a machined through hole! Good luck.
 

craig

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i looked at my old and new seals -
old Comet generator seal it is marked - MFC 146 SC 0.875 1.375 0.25,
it is a single lip seal
the new seal to be installed is marked - 4 229 TC 22 35 6
it is a double lip seal
Craig
 

ogrilp400

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G'day Craig,
What you have been given is a metric seal. It is about .003" larger on the OD and .010" smaller on the ID and a bit narrower but it will fit ok. The double lip is but a bonus as it too will add to the sealing, except in my case where two of those are still not stopping the oil bucketing out.

Phelps.
 
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