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MG TD TF 1500 - Roller cam

Anyone have a distributor drive problem with a roller cam ?
Thanks
Charlie
c mac quarrie

Why would you? The distributor drive gear on the roller cam is the exact same as the distributor drive gear on any other cam.
Gene Gillam

There are issues with misalignment of the gear if the correct spacers aren't used for a particular distributor--
You have to end up with 2 1/4" from the centre of the gear to the bottom face of the distributor
NOT 2 1/8", not 2 3/8" --------2 1/4" is required to mesh properly

Have a read here-----stolen article, but good description of what's required---
""
Distributor model interpretations are: Prefix D indicates = Distributors. KY= die cast body with pressed steel contact breaker base. "4" = four cylinder. A= automatic advance. Specific distributor numbers follow, eg 40162 etc.

The type of block, compression ratio and camshaft all influence the choice of distributors. Three models of distributors are available for the XPAG - XPEG engines as follows:

1-Model DKY4A - This model was fitted to the TC and early TDs and is fixed to the engine block using the TC microadjuster or TD external clamp and 1/8" spacer ring. The measured thickness of both of these types of fixings is 1/4" total. The length from the center line of the drive gear to the bottom of the distributor body is 2-1/2" on the model DKY4A distributor. Therefore, using a TC micro-adjuster or TD clamp and ring fixing results in a center line gear to bottom of fixing of 2-1/2'' - 1/4" = 2-1/4", this is the portion of the distributor that is inside the block. Using these distributors for the late TD and TF, a spacer ring of 1/4" thickness must be used or use two 1/8" early TD spacer rings to arrive at 2-1/4" gear to effective distributor bottom. The late TD and TF use a different block and side clamp cotterbolt to clamp the distributor.

2-Model D2A4 This model was fitted to the late TD's and all TF's and is fixed to the block using a single cotterbolt with a cut out on the side on the rear of the distributor (no external clamp or spacer rings). The length from the center line of the drive gear to the bottom of the distributor body is 2-1/4" and again this is the length of the portion of the distributor that is inside the engine block, same as the TC and early TD.

This distributor cannot be used in the TC or early TD block as no convenient means of fixing the distributor to the block is available without using the TD 1/8" thick external clamp ring. Use of this ring results in gear to effective bottom of distributor height of 2-1/4"- 1/8" = 2-1/8" and the gears will not mesh properly.

3-Model DKYH4A - This model was not originally fitted to the TC, TD or TF but is suitable for use in any engine. The length from center line of drive gear to the bottom of the distributor is 2-3/8", therefore, for the TC and early TD use the TD clamp only without the 1/8" Spacer ring. Resultant "in block" length to center line drive gear is then 2-3/8" - 1/8" = 2-1/4" For the late TD and TF use the early TD 1/8" spacer ring only and lock the distributor by the cut-out side cotterbolt lock bolt.

Resultant "in block" length to center line gear is still the correct 2-3/8" - 1/8" = 2-1/4"

Please note if you use the TC micro-adjuster with this distributor the drive gear will be 1/8" too high and will not mesh properly with the cam gear (ie: 2-3/8" - 1/4" = 2-1/8" only in block). ""
William Revit

Great informative post Willy. Cheers
Peter TD 5801
P Hehir

Willy the spelling of the word 'center' as opposed to 'centre' suggests it was penned by an American. Cheers
Peter TD 5801
P Hehir

Believe the author is Bob Grunau...a Canadian.
Gene Gillam

Gene I'd always thought the Canucks spoke and wrote English the English way. It's a good day when you learn something new. Cheers
Peter TD 5801
P Hehir

Yes, it was Bob who wrote that for the TABC group.
Original page: http://www.mg-tabc.org/library/distributor.htm
Steve Simmons

Peter-All
My apologies to Bob Grunau.
I copied the article when i spotted it here a while ago for my records and couldn't for the life of me remember where from, hence, I said it was stolen---
I seek no credit at all, just passing on what i believe could be possibly behind Charlie's gobbled up gear problem.
All credit to Bob Grunau.

willy
William Revit

If Bob is still around he certainly has my thanks. It's a really informative piece and is the sort of substantial material that should be shared far and wide. Sorry for side tracking your thread Charlie by delving into North American/Canadian orthographic variations. I have four cams, not counting the roller cam and I've very recently inspected another seven. The thing that they all had in common in relation to the worm gears is that the distributor gears were ALL perfectly intact. Of the eleven only three had gear damage and that was just to the oil pump gear, with chipped teeth often 180 degrees apart. My response to your question is 'I certainly hope not', as I have one in the car I'm restoring. I've noted your email address and will contact you if I do. Cheers
Peter TD 5801
P Hehir

Charlie you have E mail.
Len
Len Fanelli

Peter Hehir.

I can assure you that Bob Grunau is still very much around. I'm frankly shocked that as an expert MG restorer you have never heard of Bob who is legendary in the MG world. Nob has raced, restored and owns some of the finest (and rarest) MG's. He has also provided free advice to owners around the world

Not to preach Peter, but when you use material, especially from a publication, always retain the attribution.
W Worden

Three corrections are in order here Mr Worden. I'm hardly an expert restorer and would be the very last person in the T fraternity to describe myself as such. Secondly if you read this thread carefully you'll see that what you're suggesting simply didn't happen. And finally of course I've heard of Bob Grunau. I emailed him some years back but have no idea where he lives or what his present situation is. We are a long way from the North American continent...
Peter TD 5801
P Hehir

Peter isn't the one who posted the article, rather it was Willy. And it seems obvious he wasn't trying to take credit for Bob's work. He simply didn't know of it's origin and apologized when it was revealed. I see no problem here.
Steve Simmons

Thanks Steve. Cheers
Peter TD 5801
P Hehir

This thread was discussed between 17/07/2020 and 20/07/2020

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