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MG TD TF 1500 - Sputtering.... eh, not so much

After adding the heat shield and changing to non-ethanol gas.....

First, I drove the TD about 20 miles round trip to an AACA meeting last night... DANG this thing a kick-butt fun to drive. It was quite cool out and the water gauge never topped 93*C. IT RAN LIKE A TOP.

Without changing anything, this afternoon I took her out for a burn at 82-84*F air temp.

After about 10 miles and the water gauge at 95C+ and varying up to 100C, the sputters started in again, but not as bad as before, not to dead stick. I stopped once to let her cool down for 10 minutes. It took a while to get an even running engine (hot re-start). I did manage to get the 5 miles back to home sputtering all the way, never getting much faster than 35mph or so for lack of power. Thank God for back roads, I'd have been run over on the highway.

Here's the deal. I'm looking for a Volvo engine/trans. (Kidding). How about a side draft Webber? Maybe not kidding.

I've got a heat problem. Too many great trips at cool temps, too many problems when HOT.

I'm SERIOUSLY thinking about an air scoop and 4" hose to vent some cool air onto the carbs!!!! Seriously.

Maybe the plugs are not shedding heat to the block properly a pre-detonation problem?? I'm using Champion N5C. They're getting just a tad black-sooty now.

Carbs rebuilds despite being professionally done before I got the car may not be as up to snuff as I hope they are. That might be my next step - along with a radiator boil-out and new water pump.

Volvos run better than this.

.....
MAndrus

Sounds more like timing than a carb/radiator problem. Send your distributor to Jeff Schlemmer at Advance Distributor, and then set your timing correctly so that there is 35 degrees total advance. Use a good digital timing light showing total advance; eyeball and "close" are just not good enough.

I used to have a Mustang shop, and 3/4 of all cars brought to us "needing a new engine" or "needing a new radiator" were due to faulty or improperly-set vacuum advance mechanisms. Less than $100 to check and re-set the advance and timing, and they ran cool and fine.


Tom Lange
MGT Repair
t lange

I agree with Tom. The temp going up to 100°C on a drive like you described is not normal (running at 60+ mph in mid summer between Tacoma and Bremerton I never had the temp above mid 90s). What do your grill slats look like? Are you able to stand back 10 to 20 feet and see the radiator clearly? If not, the slats need to be opened up so you can see the radiator. This is, of course in addition to Tom's suggestion. Cheers - Dave
D.W. DuBois

Timing was set last month by a mechanic that works on all of the club member's cars. But, I will have a look tomorrow to be sure. I've got a digital light.

I can't think timing gets better with a cool-off, but the symptoms may. So, I'm keen to have a look at this.

Slats:


MAndrus

90% of diagnosed carburetor faults are in actual fact ignition problems. I could have disassembled my carbies recently due to back firing and engine missing when under load. See my post titled Low Tension Voltage, electricity will always take the shortest route to earth.
G Evans

I would try a colder plug, which head is fitted to your car? easy to carry a spare set, switch out if symptoms show.
mog

Dave may be on to something. The long available grill slats are wider than original. See attached shot of my original slats. Hard to tell for sure, but yours look pretty closed up. You can carefully twist/bend them to open up a little, possible but difficult to do without removing the rad shell. George


George Butz

MAndrus,
Before you go adding airscoops etc,, You do have a fair amount of things on your badge bar that might disrupt your air flow into the rad,,
Whenever our TD started to run hotter than I felt comfortable with, a timing and point adjustment always cured it,,, I do mine by adjusting till it runs smooooth.

Steve
SPW Wincze

According to Champion's site N5C plugs are an alternative for the WSM's recommended Champion NA8. B6ES is also shown as an alternative for NA8.

I'll stick with N5C plugs for now.
...
MAndrus

Mitchell, i have identical problem, runs great for 30 mins then splutters and eventually stops.
have done: new pump, insulated fuel pipe, heat shield for carbs, timing, carbs tuned.
next looking at ignition, new ht leads etc.
i have electrinic ignition.
Mike TD29330
M Lees

According to Champion's site N5C plugs are an alternative for the WSM's recommended Champion NA8. B6ES is also shown as an alternative for NA8.

On another forum, NGK's BPR6ES plugs were recommended. Something to do with resistor/non-resistor...

I'll stick with N5C plugs for now.
...
MAndrus

I had a similar problem. From out of no where the TF would start OK run some then stutter and crap out. After a few minutes get started again but run terrible. Pulled the distributor and sent to Jeff. He found the shaft/cam was slightly out of true.
He also said the points spring could have hit a natural frequency and really screw up the spark distribution.
I'll have the distributor back by this coming weekend.
Peter 54 TF
Peter Dahlquist

I'm with George, those grill slats look to be almost closed. I would suggest opening them up quite a bit. That should get your engine temperature down to the low 90s/ upper 80s. Cheers - Dave
D.W. DuBois

My original slats had suffered bird strikes & other abuse prior to purchase. When I decided to straighten mine I took the time to make a ply form about 6" long which matched the inside profile of the slat perfectly, attached a handle to it & set about re-bending each of the slats. Took a few hours in front of the TV but the end result was worth it. They look brand new. I also decided to open them so as to improve the airflow. Cheers
Peter TD 5801
P Hehir

OK. Big day yesterday....

New pertronix igniter, not new ign. system, just replaced points. (Kinda surprised you need to re-wire the coil, but it's all reversible and a snap to jam the old points back in in a motel parking lot if need be.)

Rock solid timing at 35*. With the points the timing jumped about 3/8" - 1/2" to either side of the mark. With the solid state points, it's staying within 1/4" or less of the mark. I don't think this is a contributing factor to my overall troubles, but I am glad to see that it is at least if not better accuracy-wise.

Once again checked and lubed the mech. advance mechanism.

New exhaust system, see picture. I'm pretty sure getting rid of the old mess of a system and going back to factory spec in stainless and getting the exhaust to leave just a little bit easier can't hurt. Besides, the sound is awesome, just like I remember. Surface rust inside those 1" pipes and mufflers causes resistance and turbulence. I only use SS in ALL of my exhaust systems.

Opened the grill slats.

Flushed the cooling system and replaced the metal "Y" pipe and it's hoses. Quite a mess in there.

Now.... I just need a hot day to test to failure. Again. Maybe next week.

In the meantime there's a Scottish festival/European car show on Saturday about an hour away via back roads. 23 British cars from my club are going. I'll push it as a flaming smoldering hulk if I have to.

In two weeks.... the new Dave Clark axle goes in! Can't wait.
......


MAndrus

"In the meantime there's a Scottish festival/European car show on Saturday ..."

Mitchell, is that the one at Furman near Greenville, SC? If so, I'll see you there. Jud
Green '53 TD
J K Chapin

I'll be there along with about 26 members of the British Car Club of Western NC.

.....
MAndrus

I think you need to re-think the swap from Pertronix back to points. Your rewiring comment tells me that you have a positive ground system. This means that one side of your coil is connected directly to ground. Your Pertronix Igniter plate has two wires coming from it, your old points plate only has one. When you reinstall the points plate you are automatically connecting one side of the points to ground. You would need to be connecting it to your -12v terminal.

If you had a negative ground system you could do the quick swap back to points. (I do it often for show-and-tell.) Sorry about that. Bud
Bud Krueger

Changed the coil, ht leads, dist cap & fitted red rotor.
car runs sweetly - looking forward to long run tomorrow.
M Lees

M Lees, I ran the car 80 miles round trip last weekend, not a hiccup. I've run the gamut and have come to the conclusion that some combination of changes I made allowed the engine to run where otherwise it might have sputtered to a stop. (fingers are still crossed though)

The next day over 85F will tell.

I will say that I think the crummy exhaust that was on the car had something to do with it. (See my "Exhaust System" thread) Immediately after installing a properly made Bell system the temp gauge fell 3-5*C. I'm going to guess the exhaust manifold's temp is lower now, maybe I can ditch the heat shield. The exhaust was truly the last thing I could think of to try changing, everything else had either been swapped or adjusted to within an inch of it's life.

My next tank of gas will be mid grade with ethanol just to see if the problem re-appears. It would be great if I didn't have to hunt for ethanol-free gas.

.....
MAndrus

Guys,

Please remember that our dizzy are an alloy casing on a steel shaft, with old age the bond becomes tired, and when the alloy gets hot it can and does separate from the steel. Having had this happen to me with 3 distributors the first thing I would do when you sputter to a stop is jump out, lift the hood and grip the top of the dizzy and see if it moves side to side, one of mine had up to a 1/4" of play when this happened on a hill climb, but ran sweet as getting there and home when every thing was cooler.
B W Wood

B W, that is interesting.

...
MAndrus

Had mine hooked up to test equipment, monitoring advance.
did not change up to spluttering starting.
changed loads bit by bit, coil was the culprit. At least i know all other components are AOK.
M Lees

When I was dealing with the sputtering and stopping extravaganza, I too changed the coil as it was a Lucas original and almost too hot to touch. I changed it and it ran great but the sputtering continued on the third trip out.

....
MAndrus

This thread was discussed between 21/05/2015 and 27/05/2015

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.