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I am about to begin restoration. I know it is an early model (Nov '50?), Car Number 4618, Engine Number 5017. Since I am going to rebuild the engine, probably the transmission, and possibly the rear end, I would appreciate recommendations for internal upgrades to these components. I don't want to change the external appearance if possible, but would like to be as up to date as possible with the internal components. Thanks!
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T-Series Beginning TD Restoration
- Thread starter Bill_Reid
- Start date
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I've been collecting a list of special little things you need to know in restoring a TD. Here is the list so far:
MG TD "Gotchas"
1. Must keep the generator belt very loose--1" deflection when pushed between the water pump and gen. Otherwise, the generator bearings wear very quickly.
2. The oil pump drive gear is held on by a rolled pin, which is not strong enough. It breaks eventually and can damage the camshaft gear. Not sure what to do--maybe a solid steel pin pressed in with red Loctite?
3. Pinch bolts for the piston wrist pin are very difficult to torque properly because a socket will not fit between the bolt and connecting rod. Use a metric 12.9 grade hex socket cap with a 12.9 grade lockwasher.
4. Two different camshafts are used, one before no. 24116 and one after. These have different valve adjustment specs. It is possible that an early cam was replaced by a later one or vice versa, so it's hard to be sure which you have. See the measurement method from Dave DuBois, https://www.ttalk.info/CamshaftID.htm. Lash is 0.019 for the earlier one, 0.012 for the later (hot).
5. Two distributors were used on XPAGs. The points cam is more square in the later distributor; it is type no. 40162E and is called a "high lift" cam. the point gap is 0.014-0.016. For the earlier ones, the distributor is 40162 (no "E" suffix) and the gap is 0.010 - 0.012. It is possible to distinguish between these visually; the high-lift cam is noticeably more square.
6. Two spark plugs are used in XPAGs; one has a 1/2" reach, for earlier cars, and the other is 3/4" for later cars (after 22735). NGK B6HS is the 1/2" and B6ES is the 3/4". It is easy to distinguish with the head off; the end of the threaded part of the plug should be flush with the inner surface of the combustion chamber. Also, the early heads have oval holes for coolant and in the later, those holes are round.
7. The clutch linkage's threaded operating rod tends to break where it attaches to the lever on the side of the oil pan. It can be modified to prevent this, or the bushings and clevis pins can be replaced. See https://www.ttalk.info/ClutchLinkageFix.pdf.
Another is high clutch sensitivity, so it is difficult to get a smooth start. See the same article for a fix.
8. Another clutch problem: if the cable clutch has been replaced by a rod linkage, it can interfere with the hole in the pedal box. It is also possible to push the clutch pedal too far, causing clutch damage. See https://www.ttalk.info/Tech/Clutch_stop.htm. You also will need to enlarge the hole in the pedal box.
9. Because of its unusually long stroke, the crankshaft in an XPAG engine can crack and fail. This results in a problem known as a "blown engine." The crank should be magnafluxed as part of a rebuild.
10. Small water passageways near the freeze plugs can plug up. Be sure they are open.
11. When installing freeze plugs, be sure they are tight and use a sealant to prevent small leaks. See https://www.spriteparts.com.au/tech/welch.html.
MG TD "Gotchas"
1. Must keep the generator belt very loose--1" deflection when pushed between the water pump and gen. Otherwise, the generator bearings wear very quickly.
2. The oil pump drive gear is held on by a rolled pin, which is not strong enough. It breaks eventually and can damage the camshaft gear. Not sure what to do--maybe a solid steel pin pressed in with red Loctite?
3. Pinch bolts for the piston wrist pin are very difficult to torque properly because a socket will not fit between the bolt and connecting rod. Use a metric 12.9 grade hex socket cap with a 12.9 grade lockwasher.
4. Two different camshafts are used, one before no. 24116 and one after. These have different valve adjustment specs. It is possible that an early cam was replaced by a later one or vice versa, so it's hard to be sure which you have. See the measurement method from Dave DuBois, https://www.ttalk.info/CamshaftID.htm. Lash is 0.019 for the earlier one, 0.012 for the later (hot).
5. Two distributors were used on XPAGs. The points cam is more square in the later distributor; it is type no. 40162E and is called a "high lift" cam. the point gap is 0.014-0.016. For the earlier ones, the distributor is 40162 (no "E" suffix) and the gap is 0.010 - 0.012. It is possible to distinguish between these visually; the high-lift cam is noticeably more square.
6. Two spark plugs are used in XPAGs; one has a 1/2" reach, for earlier cars, and the other is 3/4" for later cars (after 22735). NGK B6HS is the 1/2" and B6ES is the 3/4". It is easy to distinguish with the head off; the end of the threaded part of the plug should be flush with the inner surface of the combustion chamber. Also, the early heads have oval holes for coolant and in the later, those holes are round.
7. The clutch linkage's threaded operating rod tends to break where it attaches to the lever on the side of the oil pan. It can be modified to prevent this, or the bushings and clevis pins can be replaced. See https://www.ttalk.info/ClutchLinkageFix.pdf.
Another is high clutch sensitivity, so it is difficult to get a smooth start. See the same article for a fix.
8. Another clutch problem: if the cable clutch has been replaced by a rod linkage, it can interfere with the hole in the pedal box. It is also possible to push the clutch pedal too far, causing clutch damage. See https://www.ttalk.info/Tech/Clutch_stop.htm. You also will need to enlarge the hole in the pedal box.
9. Because of its unusually long stroke, the crankshaft in an XPAG engine can crack and fail. This results in a problem known as a "blown engine." The crank should be magnafluxed as part of a rebuild.
10. Small water passageways near the freeze plugs can plug up. Be sure they are open.
11. When installing freeze plugs, be sure they are tight and use a sealant to prevent small leaks. See https://www.spriteparts.com.au/tech/welch.html.
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Bill, The run down Steve just gave is a valuable piece of information and quite thorough, nice job Steve. I would only suggest that when looking at the cam, mic. the journals to make sure they are all equal and if you pull the cam, mark each lifter so it goes back over the same lobe. If there is uneven wear, I'd replace the cam and lifters. PJ
David_DuBois
Jedi Warrior
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"Pinch bolts for the piston wrist pin are very difficult to torque properly because a socket will not fit between the bolt and connecting rod. Use a metric 12.9 grade hex socket cap with a 12.9 grade lockwasher."
This is an extremely important step. If the wrong pinch bolt is used or not torqued properly, it can break while driving, resulting in an engine that is reduced to junk in microseconds.
"The clutch linkage's threaded operating rod tends to break where it attaches to the lever on the side of the oil pan. It can be modified to prevent this, or the bushings and clevis pins can be replaced."
This is only a problem in the early cars that have had the cable operating linkage replaced with a rod operated linkage. The proper fix for this is the installation of the clutch stop bolt in the pedal box, linked in #8 of Steve's post.
Cheers,
This is an extremely important step. If the wrong pinch bolt is used or not torqued properly, it can break while driving, resulting in an engine that is reduced to junk in microseconds.
"The clutch linkage's threaded operating rod tends to break where it attaches to the lever on the side of the oil pan. It can be modified to prevent this, or the bushings and clevis pins can be replaced."
This is only a problem in the early cars that have had the cable operating linkage replaced with a rod operated linkage. The proper fix for this is the installation of the clutch stop bolt in the pedal box, linked in #8 of Steve's post.
Cheers,