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MG TD TF 1500 - Distributor Issue

Tonight I tweaked the the timing after a recent pertronix install to 30 degrees BTDC at 3000 RPM on my '53 TD. I had previously followed Bud Kruger's advice and set staic timing at about 1/4" to the right of the timing notch. Using an adjustable light, only minor tweaking was required for the 30 degrees BTDC at 3000 RPM.

I decided to check the timing at 1000 RPM, and it came out to 20 degrees! After researching the archives, I'd like to confirm my diagnosis or get expert diagnosis of the problem. It appears from what I have read that I probably have a advance spring issue with the spring that comes into play first (weaker one?). It's obviously not correct as I believe I should see about 5-10 degrees, not 20 at 1000 RPM. also, when checking the rotor for movement and spring return, I can only move it about 5 - 7 degrees before it stops and I let it spring back.

I'd appreciate any input on this, and also recommendations as to where to send it for repair. Thanks in advance.

L Karpman

Larry - I don't know enough about the advance curve of the T series distributors, but someone to talk to and perhaps send the distributor is jeff at
Cheers - Dave
David DuBois

Thanks for the info Dave. I have the Advance Curve page from Bud's Ttalk web site, but assume that they are based on fuel of the era. I used what seems to be the commonly accepted 30 degrees BTDC at 3000 RPM gleaned from this forum. Frankly I don't what what that would equate to at 1000 RPM, but I suspect 20 degrees BTDC may be too much. I really don't know.

Can any of you out there that have their TD timing set at 30 degrees BTDC at 3000 RPM tell me what your timing is at 1000 RPM? That would sure help me know what I should be looking for.

Barring a distributor rebuild, seems I have two choices. Leave it as is and possibly have too much advance at 1000 RPM, or reset the timing to about 10 degrees BTDC at 1000 RPM and wind up with insufficient advance at higher running RPMs.

Any further input will be appreciated.

L Karpman

Just a guess ...but did you look at the springs under the "points" plate?
When I did the pertronox on my TF I found one of the springs on mine was broke!
Been fine since re-placing (and re-moving broken pieces).
Another little "tid-bit" I remember picking up from this BBS years ago:
In 4th gear at low RPM's does you gear shift "chatter" ...I recall reading this is a good sign that advance is not correctly set and/or functioning correctly!
Such was the case with mine!
(This was something I checked before acquiring an adjustable timing light!)
David TF 1500 #7427
David Sheward

Thanks Dave. I was going to wait for some input before removing the distributor plate. I did test drive the car this morning, and can say she is as strong as ever, maybe better. No rattle in 4th gear at low RPMs either.

I just scored an inexpensive advance timing light, so I won't need to depend on my friend who kept me waiting a month or so to use his :-) Right now my right dizzy clip is opposed to the usual bolt, so I have to upset the timing to remove the cap, then reset the timing after reassembly. So, when my light gets here I'll pull the points plate (or more correctly the Pertroxix plate) and check the springs. Shoulda done that when I put the Pertronix in anyway. DOH!

Still would like to know what other TD owners with advance at 3k RPM set at 30 BTDC are seeing for advance at 1k RPM.

Thanks again

L Karpman

Larry, a couple of questions - 1) what is your Engine #? 2) what is your distributor model #, e.g., 40367, 40368, etc.? Weather permitting, I may be able to do a plot of mine on Monday.
Bud Krueger

Bud: My engine # is 24722. I cannot read the distributor number without pulling it. I tried using a mirror, but the etched numerals are too hard to read and a bit distorted. I'd still be curious, as you are set at 30 degrees at 3k to know what your 1k timing is. Thanks for the efforts both now and in the past.

L Karpman

Larry, if the car is driving well, revving nicely and not knocking or overheating then I would work on the old maxim " If it aint broke, don't fix it" . Regardless of all the figures, the final and most important factor is the road performance. Regards, Richard.
R Payne

A agree Richard. That said, I am a "bit" concerned about the 20 degree advance at 1000 RPM. However, the car doesn't "live" at 1000 RPM for very long anyway. I must say it seems to perform better than ever, so I just want to ensure that nothing damaging is happening at the lower RPMs. Won't know about overheating till Summer gets here.

L Karpman

To Bud, et al: Bud, for purposes of your info, just assume for the moment I have a 40368 distributor. Also, I pulled the plate and the springs appear OK. One tighter than the other, which seems to be confirmed by the archives. That said still interested in the advnace curve you come up with, plus the two questions below.

1. If my advance of 20 BTDC at 1000 RPM is too far , and OK at 30 BTDC at 3000 RPM as the archives suggested, will this have adverse affects?

2. Could the reason be a weak primary spring, allowing too much advance at lower RPM? Or...??

Thanks to all

L Karpman

Larry, I'm afraid that the "Montreal Express" has decided to give us another whack. Back to single digits (deg F) for the next few days. Sorry about that.
Bud Krueger

No problem Bud. Drove the car to the shop today for the 4.3 install, so all can wait till your convenience anyway :-) It's going to be in the mid 70's (F) all week, and the car will be somewhere else :-(( Oh well, can't have it all I guess.

Thanks for all the help

L Karpman

This thread was discussed between 03/03/2007 and 06/03/2007

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