MG TD TF 1500 Anyone have a Lucas 40048AF distributor BBS discussion at MG-Cars.net

MG TD TF 1500 - Anyone have a Lucas 40048AF distributor

I cannot remember how I obtained the 40048 distributor in the attached photo, and as it only has one clip I do not know if I have ever used it. It is also rather worn, as there is 1mm of up and down play in the shaft. However, pushing the shaft down, which is where it would be in operation as a result of the rotation of the camshaft gear, I have measured as follows. From the bottom machined face of the cast body to top of the gear = 57mm, and to the bottom of the gear = 69mm. As the wear on the gear is to the top, it is obvious that it has been fitted too far into the hole in the block. Because the distributor was used with the micro-adjust clamp, my guess is that someone fitted it using the later clamp without micro-adjust, which was thinner.

R WILSON

I have just remembered that there is a photo of a 40162 distributor in a thread in these TD-TF pages, so I have attached the photo. It has the 3mm spacer, so perhaps the spacer came with the distributor. I have another Lucas parts list for the 40162 distributor, and it mentions a thrust washer, which could be the spacer, but the washer is not given an individual part number.

R WILSON

Tim. I sent you a separate email. My TD has Distributor DKY4A 40048D Dated 9/48. I am reasonably sure it is not original for my 11/50 TD. It does have a 0.125" spacer above the holding bracket. Again, can't say the spacer is original, but it has not had any issues running my engine. A note to Jeff Schlemmer at Advance Distributors may give more information. PS. If anyone has a TD distributor with a date of 1950 they want to trade or sell, I am looking for one.

Bruce Cunha

Bill, the TC was equipped with dist 40048 from 1946 until 1949. The TC had the micro adjuster installed and a clamp . One would expect to use a spacer if the micro adjuster was removed. The 40162 distributor was fitted to the TD in 1950, coincidentally when the micro adjuster was dropped. You would think that if a spacer was required with the introduction of the 40162 Lucas or MG would have included it in their parts catalogs or workshop manuals. They did not. So either the 40162 distributor was changed to account for the lack of a micro adjuster or Lucas and MG did not think the driven gear moving down 1/8" was a big deal. Regards Tim

Timothy Burchfield

Steve, regarding the thrust washer: The manufacturer provided the distributor gear for the 40162 not Lucas. It was not a Lucas part. Therefore it makes sense that MG would provide the thrust washer since Lucas would not know what thickness was required for the manufacturer's installed gear. Regards Tim

Timothy Burchfield

I did a picture and measurements on my distributor

Bruce Cunha

I just noticed something interesting, the hole to attach the early TD distributor clamp to the block is slotted. It can be raised and lowered. This would allow you to raise the distributor 1/8" and with the thickness of the clamp (1/8") you would have your 1/4" that a spacer would provide. I'm not convinced it is necessary but perhaps thais was how MG addressed the loss of the micro adjuster thickness. Tim

Timothy Burchfield

Here's a picture of the clamp in the raised position. Notice the wear marks on the vertical part of the clamp where the block bolt had previously been tightened at a higher level. Tim

Timothy Burchfield

With Spacer ring

Richard Cameron

Another Photo

Richard Cameron

3rd Photo

Richard Cameron

Last photo

Richard Cameron

Not to confirm or deny either position, only what I have. Disclaimers. 1) This is a replacement engine(16052 from TD 15590, should be 13135). History unknown. 2) By 1969 it needed a rebuild BAD, although my odometer was only 44400. 3) My son and I took it apart in 1983, rebuild took place over '83, and '84. 4) We did a very poor job of documenting things. 5) The bolt holding the bracket looks correct. It has a head drilled and seems to be anchored. I was working on oil leaks and decided to see if I had this spacer. No. But it could have been left out during rebuild or before I got it. Without loosening the bracket fixing bolt the distributer is free to turn if the locking bolt is loose, sot the fixing bolt does not touch the distributer internal shaft, but must sit in the grove. Note the gap above the bracket. Is it 1/8"? looks smaller but perhaps 3/32" Close enough that I don't think I am not going to add one unless I take the distributer out of the car in the future. HOWEVER: If anybody has the OD and the ID dimensions I would appreciate it. BTW that magic shoulder bolt lists for $35 (433-530) at Moss. Jim B.

JA Benjamin

Jim, sorry for adding this post. I looked at your picture for several days and finally decided to add comments for the benefit of a new person who might read this thread in the future. All of us have been there at one time looking for information. The distributor clamp being discussed, and the distributor, are designed to float a small amount vertically, but NOT allow any rotation of the clamp and distributor that would affect timing (hence the vertically oblong hole in the clamp). This “floating” action is especially important when using cams that require VERY high valve spring pressure not envisioned by XPAG designers (flexing and gear mesh). For that reason, the shouldered Lock Bolt 23 should be installed WITHOUT an exterior washer as seen in the above picture that would lock the clamp to the block and apply pressure to the side of the distributor body. This defeats the purpose of the clamp design and it is not the best location to place a ground wire. Because the clamp and distributor can float a small amount vertically, the distributor NEEDS a ground wire and it can be run from the bolt that locks the clamp to the distributor body to a suitable location on the block. Previously Discussed Background: Regarding the shouldered Lock Bolt 23, this should normally NEVER make contact with the distributor body. It only makes contact with the body when the much discussed 1/8-inch spacer ring is missing and the interior end of the bolt rest on the bottom edge of the groove in the body of the distributor or is smashed against the distributor body. When installed correctly (as Steve, Ron, Richard and almost everyone else has said) the weight of the distributor rest on the spacer/clamp/block and the end of the Lock Bolt is positioned within the groove on the distributor body, but NOT touching the body or edges of the groove as shown in previously posted pictures. The bolt was designed to use lockwire to prevent it from unthreading. The PO of my wife’s TD omitted the 1/8-inch spacer and Lock Bolt 23 made contact with the distributor since the groove was now below the end of the bolt. He then tightened the bolt to lock the distributor in place; smashing and damaging both of them. Her TD now has the correct spacer and the distributor “floats” vertically as intended. The engine is strong and runs very smoothly. If there are errors in what I have posted, please make corrections as needed.

WHT

There are two different shaft lengths in distributors fitted to Y-Types, which were produced alongside the TC. The Tourer has a long shaft & a 0.125" spacer, as the YT did not have the micro-adjuster as fitted to the TC despite having the twin carb engine. The Saloon (XPAG single carb) has a short shaft dizzy and requires no spacer to ensure the correct alignment of the dizzy drive gear with the camshaft. As you can see, the slot for the lock bolt is the same distance from the drive gear in both dizzy types. Both have the simple lock plate as was eventually fitted to the TD some years later. I hope this clarifies some of the confusion some people might have with the various XPAG distributors and their mounting height. Tony Slattery The Classic Workshop Black Mountain Australia

A L SLATTERY

This thread was discussed between 29/08/2019 and 04/11/2019

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