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MG TD TF 1500 - Acceleration and Top Speed

I *think* I've got the timing set pretty well, I have decent acceleration in 1st and 2nd, but moving into 3rd it lacks power, 4th offers almost nothing. I've tried moving the distributor in minute adjustments CW and CCW and nothing works, top speed is about 40 and takes a long time in 4th to get there. I don't want to run about at 70mph but if I'm going to get this thing out on the open road on the weekends then 50-55 needs to be obtainable. What should I look at next?
SD Denham

Fuel.
Jim B
JA Benjamin

Check spark plug wire positioning; make sure that numbers 2 and 3 have not been switched.

BL
B. F. Loughridge

Could be fuel either too rich or too lean, have you checked the compression?? Check the plug color ?? Are the brakes dragging??
Steve Wincze

You say you "think" you have the timing set??? It either is or isn't. What degree BTC is it set?
Is the advance mechanism functioning properly?

i am less inclined to think it is fuel... but what do I know. Regards, tom
tm peterson

I think Tom might be onto something. My bet would be one of the dizzy advance springs. Cheers
Peter TD 5801
P Hehir

One other thought.
Have you checked your point gap.
If it's too close, you will have poor high speed performance.

Jim B
JA Benjamin

Mr. Denham, I read your earlier thread as well and I saw no mention of a compression test. I think you should:

Run compression test on all cylinders
Check spark plugs and plug gaps
Adjust Valves
Adjust points gap on distributor points
Confirm operation of advance weights and springs
Set timing for max advance as mentioned in earlier thread - at about 32 degrees at say 3,000 RPM

Then,
Check fuel system:
Pump filter clean?
Float bowl filters clean?
Jet adjustments/float levels correct?

I would double back and do a methodical tune up - something will jump out at you as having been incorrect.

Let us know what you find
DLD

The book calls for setting the timing dynamically. Dynamically is without the engine running, pushing the car in gear until #1 (front) piston is at TDC. When timing with a light, remember the timing has already advanced 5 degrees-- when idling at around 700 rpm.

Likely most people will recommend a timing 5-10 degrees more advance than the book calls for. So, at idle you will be looking for 10-15 degrees advance. Is your timing light showing that the timing advances when you rev up the engine? Then returns to where it was idling? If not, your advance is sticking or messed up.

Here's a link. Ignore about vacuum advance.
http://www.chicagolandmgclub.com/techtips/mgt/tune_up1.html
D mckellar

What is your timing at idle?
What is your timing at 3500RPM?

Make sure they are both within spec, and then move on.
Steve Simmons

I agree with DLD - your car needs a comprehensive, ground-up tune-up and check of all systems - it's pointless to do any less. A T-series should accelerate smartly, especially in second and third. If it doesn't you have a problem, most likely ignition-related. But it could be fuel-related.

Do you have the NEMGT Register T-series handbook? It's the best basic guide to a step-by-step tune-up for the T-series cars.

It's unclear what you have checked and what not - or whether you own a timing light. Unfortunately, timing by ear or the seat of the pants is worthless. I run my cars at 65-70 all day, and can get there in under 20 seconds. If a car does not accelerate in third, there is something strangling it that needs to be addressed.

Tom Lange
MGT Repair
t lange

If you don't have the NEMGT Register T-series handbook, then here is a good two-part guide for MG tune up. "How To Do A Complete Engine Tune-Up" by Skip Burns.

Do Part I first. Don't skip a step.

> Part I
http://www.chicagolandmgclub.com/techtips/mgt/tune_up1.html

> Part II
http://www.chicagolandmgclub.com/techtips/mgt/tune_up2.html

Lonnie
TF7211
LM Cook

This thread was discussed between 28/12/2015 and 29/12/2015

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