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MG TD TF 1500 - Engine won't start after winter

Hello,
My TD was stopped in my garage for the rainy month of winter. I intended to drive on this sunny sunday.
But the engine only coughed on one cylinder. It never strated. Sparks are OK for all plugs, fuel is ok in the carb bowls. But with the crank handle, I found only one cylinder with compression. Valvles are moving up and down. Valve gap are OK. Then I did a leak test. 40 PSI. The three bad cylinders are leaking to the exhaust pipe. So the exhaust valves need a lapping job.
I would like to delay this operation for next winter. Is there a trick to start the engine with this low compression, hoping that a few combustion cycles improves the valves surface for the season ?
I was thinking about starting fluid (Start pilot in Europe).

Laurent.

LC Laurent31

I can't imagine anything is going to make it start if there is no compression at all on 3 cylinders. If you have some compression and it was running ok when you laid it up maybe the fuel has gone off and some new fuel might be enough to get it going.
P Willows

Did you remove the plugs and squirt some oil into each cylinder? Always a good idea after the engine has been standing.
Dave H
Dave Hill

Probably just a bit of corrosion or some loose carbon on the valve seats,or the rings might have got stuck, As Dave says a squirt of oil in each cylinder and it'll probably go, if not I'd give it a tow down the road and it'll go and probably clean itself up with a good run

willy
William Revit

I am a bit more pessimistic than Willy regarding your engine..a few month lay up should have virtually NO effect on compression in one cylinder never mind 4 (40 is pretty bad) double check your valve lash..you can try “staking” the valves ..giving a good whack on the valve stems with a block of wood struck by a hammer...a common practice on the aviation side of internal combustion engines. ..but 4 cylinders is a big number

Compression air noise in the exhaust is not rings..a squirt of oil in the cylinders will be of no help if it is valves

Good luck. Burned valves is a possibility here.

Regards, Tom
tm peterson

Been there, Done That. You have a valve that is not fully closing. I had this happen a couple of times wintering over in Wisconsin. Drove me nuts trying to figure out why it was running great when I parked it, but not running on all cylinders at startup. The valve gets a little corrosion that does not allow it to fully close.

If you want to be sure, get a cheap flexible scope that works off you phone and put it in the spark plug hole to visualize the valves.
Bruce Cunha

Laurent,

From your description I would suspect that the valve stems are stuck in their guides. An easy way to check this out is to remove the rocker box cover, spray WD40 (using the red extension tube) on the valve stems, in between the upper coils of the valve springs. Leave it for some time, repeat the process then try to start the engine. Another option, which requires a helper, is to remove the all the plugs turn the engine over with the starter motor while spraying the WD40.


John


J Scragg

Turn the engine over with the handle, at each Top dead centre check the valve clearance. If excessive you have a frozen valve, remove the rocker gear and gently tap the valve stem until it springs back.
If the clearance is OK you have a bigger problem.
Ray TF2884
Ray Lee

Thank you all.
Yes I pour some oil in the cylinders before I went to the leak test which revealed the culprit exhaust valves.
Yes I also put some WD40 on the valve stems just after the leak test.

Hammer and wood this evening on the exhaust valves.
Leak test seems better and I can feel compression for all cylinders now.
Tomorrow, I'l put back the rocker assembly, set the gaps and try to start up.

Laurent.
LC Laurent31

I've had a similar problem this year getting my TD to kick of after winter. It half way started with one or two cylinder just trying to kick. Checked compression, OK check plugs, they looked fairly good. Then I replaced plugs, checked ignition gap, right in spec, installed new wiring, still would not start. Drained the fuel tank using the fuel pump and about the first two quarts of fuel smelled like crap. I used Stay-bil fuel additive in the fall and what I drained out was still pink but I think what I had was a lot of water in the tank. I have gotten some non- ethanol fuel and will dump it in the tank as soon as the weather breaks and give it another go. A local station near sells non-ethanol fuel so I use that here on out.

Bill B.
Bill Brown

Bill,

I am not in favor of our ethanol rich gasoline, but if you have an issue with moisture, that's the best "solution."

Alcohol combines with water; gasoline lets it collect out on the bottom of the tank.

Think of a tank full of E10 gas as having a gallon of "drygas" in it.
JIM N

I always drain the tanks completely over winter and store the fuel in a steel jerry can. Plastic storage containers won't do. That way it retains all the volatiles that help for starting and keeps out any moisture. I recommend that everybody does it that doesn't use their MG over winter.
Dave H
Dave Hill

Regarding ethanol fuel going bad in a few months..I had a boat for a number of years. After dealing with an on going family tragedy I finally was able to pull the boat out of storage. I had winterized in myself for over the winter storage in an unheated storage facility. Six YEARS had passed with the full tank of ethanol fuel. The fuel looked, smelled and worked as if it had been pumped into the tank that very day. I have a 1935 Terraplane that I had on layup for 24 months during another trying period. It was also full of fuel, treated with sta-bil fuel additive, it also started right up and ran flawlessly. 30 years of over the winter storage of vehicles in northern Illinois (in the states)..at least 6 months each year, multiple vehicles, and I have never had an issue with ethanol fuel going bad. I do have to periodically replace rubber hoses that get soft.

Regards, Tom
tm peterson

Great ! It eventually started after couugh and sputter.
Thanks very much.
For sure, I will update my winter procedure : oil in cylinders and WD40 toward the valve seats through the plug holes.

Do you think I should inspect the valves next winter anyway ?


Laurent.
LC Laurent31

“For sure, I will update my winter procedure : oil in cylinders and WD40 toward the valve seats through the plug holes.”

Will WD40 last? In the past I’ve used it and several months later it was like I hadn’t sprayed the part at all. My part was accessible so I coated it with paraffin wax and it lasted. Maybe I just didn’t use enough WD40.
G D

A better wintering over lubricant is engine fogging oil. I used it on my snowmobile engine for the summer storage.

I started using it on the TD after the last stuck valve. Can't say it was the cure, but I did not have any stuck valves after starting to use it in the cylinders.

https://www.amsoil.com/p/engine-fogging-oil-fogsc/
Bruce Cunha

WD-40 is not much of a lubricant but for preventing corrosion on steel surfaces ...that is right in its wheelhouse..too much just runs off so quantity doesn’t really help.

Having said that, I agree with Bruce, I prefer fogging oil for the winter lay up.

Regards, Tom
tm peterson

Here's a silly -possibly ,idea. In some way fit a water separator to the tank so periodically the tank can be "flushed" with the fuel having been purged, returned to the tank. It logically would require a diverting valve and a means of reducing the flow from the tank/pump to ensure it functioned at the correct speed. plus a return location to the tank. May even be able to set it up in such a way that it was done automatically at set periods of time. There's the idea now over to you engineer types.
JK Mazgaj

JK,

I stuck an old fashioned "sediment bowl" under the tank. It has a glass bowl to separate and reveal any water. It take 10 seconds to shut off, empty the water and reinstall. It is great for quick inspection of dirt & rust, check if you're empty and serves as a convenient drain. Takes a lot of the guess work out of diagnosing fuel issues. It has a filter screen and I throw a magnet into the bowl to trap any fine rust that can crap up the filters, pump and carb. The valve has a reserve setting if you think you need it. There's also an extra port if you want to feed a spare pump, add a fuel return line or drain valve. They're 'period correct' for vintage racing, don't need to be wired for power and the best part is, they're CHEAP.

Jim (an engineer type and mechanic)



JIM N

Good idea Jim. Did you fit any protection from "stones" etc?
JK Mazgaj

Fuel, water and WD40 was not my question :
"Do you think I should inspect the valves next winter anyway ?"

Laurent.
LC Laurent31

I recommend investing in an inexpensive flexible scope that hooks to your phone. You can run this in the spark plug hole and visualize the valves.
Bruce Cunha

"Do you think I should inspect the valves next winter anyway ?"

Only if a compression or leak down test says you need to.
JIM N

I avoid the problem by driving in winter on dry days. It gets down to zero here so it's a bit chilly. I think the car needs to drive once a week for a half hour.
Peter Dahlquist

This thread was discussed between 29/03/2021 and 07/04/2021

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