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MG TD TF 1500 - time chain tensioner

Starting refurbishing my spare engine. One of the surprise I found was that there was no time Chain tensioner was installed even not the attachment holes or the oil hole was drilled.
Anybody here found the same situation and decided to drill and tap the required holes in the engine block?
What is the risk to drill the missing holes mainly the oil holes?

Thank you
Guenter


GK Guenter

What is the casting number of that block?

Tom Lange
MGT Repair
t lange

I'd guess it's either a very early XPAG block or was originally not from an MG. I've heard of people drilling the holes for them. Shouldn't be a problem, just be sure they are absolutely straight.
Steve Simmons

@Tom,
The Block number is unusual, as far as I can say. There are two numbers, one is stamped RDB968 in addition to the cast in Letters 3.C3
See the picture enclosed.
Cheers,
Guenter


GK Guenter

In the upper photo, the casting number is higher up, probably partially hidded by the silvery plate. The 3C3 is the casting date of the 3rd March 1943, and Morris Motors engines division did make engines during the war. The date could be 1953, but I don't think so as postwar all engines had timing chain tensioners. The RDB968 (I think that is incomplete) indicates that the engine has been reconditioned, so there may be an engine number stamped on the block to the left rear on the flywheel cover, and another stamped on a plate somewhere. It would be useful to know what other casting logos are on the block.
R WILSON

Dear Mr. Wilson,
Thank you for your comments mainly on the date of casting.
The other point is the block Number, you are right, there is a casted number on the block it is hard to read but can be 22500 as you can see on the picture enclosed.
The stamped Number below the casted Block number should be complied but between the letters there are vertical markings like RDB968 not between 6 and 8.
There is a hole for the octagonal ID Tag. The tag is missing but the painting shows the position where the tag has been located.
There is another Symbol looks like a Rhombus but there is no number or letter.
Next to the starter motor there is a Metter “A” casted in to the block.
You are also correct with your statement that the engine has been reconditioned. At the top surface of the block there is stamped A +1 +1 +2 +1. I believe that is first oversize for 3 Cylinder and oversize 2 for one.
Actual all Piston are stamped +030. I believe there was a second reconditioning.
Cheers,
Guenter


GK Guenter

22500 is a pre 1945 XPJM or XPJW block. It had bores of 63.5mm, giving a capacity of 1140cc, and it did not have a timing chain tensioner. The bores can be opened to 66.5mm for a capacity of 1250cc, but almost certainly no more. I have also heard that tensioners can be fitted to these blocks.
The rhombus, or diamond, will contain the letters MM, but on early blocks that area was never very clear.
Will think on your other points, but it is unlikely the block has been reconditioned twice.
R WILSON

In my experience the +1 and +2 figures are for the original build, where the cylinders are +.001 or .002" o/s.

Tom Lange
MGT Repair
t lange

Tom,
And the Piston diameter stamped +030 means Piston size +0.030" right?
GK Guenter

Coming back to my question:

Somebody here found the same situation and decided to drill and tap the required holes in the engine block?
What is the risk to drill the missing holes mainly the oil hole?
Thank you
Guenter
GK Guenter

The XPJM/XPJW blocks were also given tensioners after about 1945, so you need to compare your block with a later block that does have a tensioner. So long as there is metal where you need to drill for oilways or tapped holes, there should be no problem, although you will need to find a tensioner and bolts.
The RD--- stamping appears to be R/D/B/9/68, and R relates to the crankshaft journals. Undersizes are R1, R2, R3A, R4 and R4A, so a single R could mean standard size journals, but this is not certain. The rest of the stamping is also unknown, but 68 cannot be a date as by 1968 the reconditioning data was stamped onto a plate that was fixed to the side of the block.
R WILSON

Hi Guenter,
I have a long motor, with the 22500 casting number, in my shed. I believe it is from a pre-war Morris 10. The date, 1 DEC 38, is cast on the cylinder head. Your question raises several other questions.

What model MG do you have? And how keen are you to keep it looking original? If you have an MG TB, your block is probably the best match you will find. However, a block with a large MG cast behind the generator might better suit a TC or most TDs. A round holed block with casting number 168421 (without MG casting) will suit a late TD or a TF. This is the same as Wolseley 4/44 blocks which are relatively common in Australia.

Do you want to bore out beyond 1250cc? A 22500 block is not suitable for boring to 69mm.

What type of cylinder head do you have? Although early blocks and late heads can be used together (and vice versa) it is probably better if they are matched.

Your block is a rare item and might be desirable to pre-war enthusiasts? I think such blocks were once sought after by people building pre-war race cars in Australia. Could you swap yours for a block which better matches your car?

If you do decide to drill your block (after checking the details suggested by R Wilson) you will also need a timing chain cover to suit the tensioner. If you can not easily find a tensioner and coiver in Europe, email me at bobschapel@optusnet.com.au because I have covers and tensioners spare in my shed.

Cheers,
Bob Schapel

R L Schapel

Bob, thank you for response and all the questions.
I drive a 1953 MG-TD without any problems. Making long distance traveling as we did this year from the north of Italy down to Napoli and back, about 2500kim. We do such trips towing a small camping caravan trailer behind the TD. I know, people say it is crazy, but we like it.
I get the engine where we talk about in Germany for a reasonable price and I decided to put it in the Garage just in case. In preparation for a winter project I start to open the engine and check the condition. I’m surprised the engine is in excellent condition. But some questions came up and most of them was answered by the enthusiasts here in the forum.
My first question was concerning the Chain Tensioner and this question is still open. I ordered a tensioner set from Classic Automobile Electrics Ltd, Searby , North Lincolnshire. They delivered very fast and now I have it on my desk with 3 bores in it.
My Point is now,

“free to Shakespeare, drill or not to drill”

It is simple to do, but will I find an Oil Channel?
Can I damage the block?
It is amazing to find experts everywhere in the world, thank you
Guenter


GK Guenter

Why bother? You’ve had no problem up to now with the engine so why risk drilling holes into the block?
Gene Gillam

Gene, first of all I like to have a Project to do something, as I said, the Spare Engine is obviously not a TD Engine. It is an old block maybe from 1943 but refurbished. Drilled to +03 set of new Pistons +03. It seems to me that the engine never run after refurbishing. Pistons looks brand new from the head to the shirt. The “Moss Crankshaft oil seal kit” is installed.
But there is no Chain Tensioner installed. May be it is not important but I have it and my question is, what risk is it to drill the three small holes into the block.
- Find the exact location for the hole > make a template
- There is no oil channel behind > OK, forget it
- Use professional tools for the job > OK, no problem
- Brake the drill or the tap > can be a risk, work carefully
Any more risks?
GK Guenter

If the block is still on its nominal bore size (for 1140cc), with a +0.030" rebore, the capacity will be 1168cc.
The earliest use of the date code system has been found to be June 1939.
R WILSON

Just realised, if someone has fitted the Moss crankshaft seal, the bores may already have been opened out to the 1250cc size, then rebored +0.030", making them 67.262mm, giving a capacity of 1280cc.
R WILSON

the actual bore is 66,8mm
GK Guenter

That gives 1262cc. (actually 0.012" up on 66.5mm).
On the drawings I have seen, typical cylinder wall thickness, after boring to standard size, is 5.5mm, possibly a fraction more. The XPJM bore of 63.5mm has been opened out to 66.8mm, which is an extra 3.3mm, or 1.65mm extra on the radius. Thus the wall thickness has been reduced to 3.85mm - this is a thinner than the cylinder wall in an XPAG bored out by 0.1" to 69.04mm to give 1350cc, with the wall thickness reducing to 4.23mm.
(The +0.030" probably relates to a much earlier reconditioning of the original XPJM 63.5mm bore).
R WILSON



Mr. Wilson,
I found another detail:
The Dipstick is stamped "Engine Number 24407.
Can it be, that this stick is really for this old block from 1943 as you said?
Or was it replaced during lifetime?
Cheers,
Guenter
GK Guenter

This engine was produced 1939/45 for the Armed Forces. It was fitted in the Morris "Tilly" (Light Utility).

They have their own site, morris.tillyregister
They may be able to give more information.
Ray TF 2884
Ray Lee

I did not know, for an XPJM engine, that the engine number was stamped on the dipstick, but I am sure it is a 1943 block. Perhaps the Armed Forces required the engine number to be stamped on all removeable parts - if this is true, maybe you should re-examine the block all over to see if an engine mumber is stamped somewhere.
If you are going to use the block for a TD engine, you will need to fit one of two appropriate sumps. In which case you need to put in the correct amount of oil, and then check the level on the dipstick, presumably after turning the engine to pump an empty oil filter full of oil. You may need to fit a different dipstick and tube.
R WILSON

Sorry, Guenter, but 24407 is the Part # of the TD/TF dipstick. Bud
Bud Krueger

A small camping caravan behind a TD does not sound crazy to me. In 1983 I towed my race TC 750 km on a trailer behind my road TC, from Adelaide to Geelong (and back) so that I could compete in both cars at the MG National Meeting.

In Australia, 69.5 mm is a common size to bore an XPAG 1250. I guess it depends on a bit of luck. I used to have a block which was originally from a Wolseley 4/44 (same as TF 1250) and it was bored to TF 1500 size (1466 cc). It had a sleeve in one bore only! Whoever did it was very lucky! It did eventually show some porosity in other bores.

Cheers,
Bob Schapel
R L Schapel

Yes - I have checked my own engine, and it has the 24407 dipstick, although the parts list states X24407. It fits through a tube projecting up from the side of the block, and is actually stamped '24407' above 'ENGINE' (I suppose to indicate that it should not be fitted into the gearbox). However, your 24407 dipstick, hopefully with a tube, has been fitted later, because the XPJM engine used an X22342 dipstick, which was very short, had a wire loop handle, and went directly into the hole in the block, without a tube.
The 24407 dipstick was used for both unfinned and finned sumps.
R WILSON

This thread was discussed between 25/09/2018 and 29/09/2018

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