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MG TD TF 1500 - Valve cover brass plate

A friend has an original valve cover that came on his 53 TD and it has valve setting of .015 on the plate. Can someone enlighten me on usage.

Thanks
Bob
Bob Wrenn

That is the suggested clearance for setting the valves... HOT

SPW
Steve Wincze

Bob,

For an XPAG/TD2/ from 1953 it should have been 0.012 as you know.

I would guess that it's a cover from some other version of the engine as used in not T cars, or a DPO has somehow changed it.

Are you sure it's not 0.019 or 0.019 cleverly altered?
Don Harmer

Bob - The plate attached to the rocker arm cover on our 53 TD was the same way - 0.015. The only thing that I could figure was that the cover was from an engine used in a different application. I don't know what that application might have been, but perhaps a query to Neil Cairns, via the Y Type Register would get a correct answer (the answer might even be in Neil's book, Living With The XPAG The Morris 'X' series Engine). I cured my situation by installing a different rocker cover with the correct valve clearance on it. Cheers - Dave
David DuBois

The General Data in the MG midget TD and TF Workshop Manual states
Engines up to No. XPAG/TD2/24115 .019 hot
Engines from No. XPAG/TD2/24116 .012 hot

Mike
Mike Hart

My '53 said the same thing, .015 on the cover. I will be setting the valves next week. What is the consensus HOT? I have heard, "stick with .012 as the manual says," and also "I do mine at .015." And if different from .012, what's the reason?

TIA

Larry
Larry Karpman

Larry - A cam that is meant for a 0.012" set a 0.015" will run noisy and be down on power. On the other hand a cam that needs 0.019 that is set at either 0.015" or 0.012" will be too tight, which will degrade power and burn valves. I have a procedure by which you can determine which cam grind you have and if the valves should be set at 0.019" or 0.012". If you would like a copy, I'll e-mail one to you. Cheers - Dave
David DuBois

The .015" plate is for the AEG122 half race camshaft. I think the plate may have been fitted if a car was ordered with this camshaft fitted from new, and it may have been available as a replacement item for any one buying an AEG122 camshaft for self fitting. I'm not sure all the dealers knew about it as I bought an AEG122 camshaft about 38 years ago (it is still in the engine), but I was not offered a replacement plate. I don't think it is a very common item.
R A WILSON

RA - Thank you for that tidbit of information. That certainly clears up a mystery that has been around as least as long as We have owned our TD (36 years). Cheers - Dave
David DuBois

"The .015" plate is for the AEG122 half race camshaft. I think the plate may have been fitted if a car was ordered with this camshaft fitted from new"

Good theory and possible, but I have a .015 tag on my late TD, which has been on it since I got it in the late 60s. The engine had not been out or rebuilt at the time, and the original owner was not prone to change anything, (especially if it cost money)
During restoration of the car and engine rebuild I checked the cam and it had the AAA3096 cam with the D2A4/3096A distributor.
This subject has come up here before and there were at least several instances of the valve rocker cover with a .015 tag. The reason was never solved factually.
There was a period where two cams used the AAA3096 part number, where one had a 8mm lift and the later one had a 8.3mm lift. I tried to extrapolate the difference in case the earlier cams were used for awhile, but the .3 mm difference didn't jive with the different in valve lash setting. Anyway I got a brain cramp and gave up, but there were more than a few cars with the .015 tag.

Dallas

Dallas C Congleton

Sure Dave I'd like a copy! I believe you have my email, but in case: lkarpman at tx dot rr dot com

Larry
Larry Karpman

Larry - You have e-mail.

Dallas - There are any number of explanations as to how that tag got on your engine, up to and including the wrong rocker cover being installed at the factory. Our TD had the same tag on its rocker cover and I just recently found a cover that has a 0.012 clearance tag on it, so it now has the correct info on it. Our cars are nearly 60 years old, so anything could have happened (and probably did in some cases) to them during their lifetime. It was not something that was a high priority in my case, especially since I determined what the clearance should be on the engine in our car, but when the opportunity presented itself, I jumped at it.

RA Wilson - After reading your post and answering it, I remembered that I have a listing of the various cams and their specs for the XPAG/XPEG engines. I called it up and checked and sure enough, the AEG122 was listed along with the 0.015 clearance spec. I have had that list for more years than I care to remember and the information just never caught my attention. Cheers - Dave
David DuBois

There is a TD .019 valave cover on Ebay right now if someone needs to purchase one. Looks to be in good condition.

Jeff
Jeff Delk

Dave,

I'll take a copy. If your engine was rebuilt at some point in it's life can you tell from your procedure how to determine what cam is in it?

Cheers
Vince
vping

Likewise a copy please Dave D. to mrmgtdmail at gmail dot com

Possibly another tech article for Mr Krueger's Tech-Talk?
Randy Biallas

Dave, I'd be honored to post a copy on Ttalk. Bud
Bud Krueger

Vince, not to hijack, but there are other non-factory cams out there. My TD came with the early .019 cam (as on the vc plate, and by serial #), and was rebuilt in the late 60s with the later .012 cam- which we knew due to the shop painting the info on the firewall (but not that a different cam was used). For some years we drove it, just really clattering. Eventually, I would just start the engine with the vc off, and find the most offensive rockers and snug down. Eventually there was an article in TSO or some club publication that told how to figure out which cam, and it was the .012. the opening/closing degrees are really different. John Twist always said that 12 was too tight, 19 too loose, so when in doubt use 15. The Crane/Moss large lobe cams were available by at least 1988, and all of those are .018 intake, .019 exhaust. George
George Butz

Vince - " If your engine was rebuilt at some point in it's life can you tell from your procedure how to determine what cam is in it?"

The procedure I have determines if the cam needs a rocker clearance of 0.019" or 0.012". there are other cams available with different clearance requirements, but this procedure doesn't tell you anything about them. I sent you and the others who asked for the procedure, both the procedure and a Excel file of other common cams that are used in the SPAG/XPEG engines and the specs on each one of them, including the clearance required for them.

George, I would have to disagree with John twist about 0.012" being too tight and 0.019" being too loose. For the AAA5776 cams 0.019 is the factory specs, for the AAA3096 cams 0.012" is the factory specs. I can't say for the AAA5776, since I don't have an engine using that cam, but the engine in our TD has the AAA 3096 cam and I have used the ).012" clearance for the past 40 years with perfect results. By the way, if you have an older AAA5776 cam, it can be sent to Delta Camshafts in Tacoma and asks them to rebuild it with the "pointy" lobes and you will get the grind from the AAA3096 on it for a very reasonable price (the owner of the shop used to race British cars, including the T series MG and he knows the cams well enough that when I took the one from our car in and set it on the counter, he told me what cam it was, what car it was from and what grind it had from clear across the room).
Cheers - Dave
David DuBois

David, This was something John put out years ago, or may have told me personally at a GOF. This may have been something to do with noisy tappets due to worn rocker arm tips that caused the feeler gauge to bridge the actual clearance? Or maybe that there are hardly any .019 cams left in existence? Perhaps that is where this came from. It makes sense that setting one of the new Crane cams or any other that was really suppose to be .019 that tight would be really bad for the exhaust valves. I have two or three cams in the attic- I'll dig them out and check them out, look for part #s, etc just for curiosity. George
George Butz

More info: David, I just read Hal Kramer's article in the June 2001 TSO, and Hal suggest going .003 loose when in doubt, or .015 or .022, He also says that determining which cam is beyond the scope of the article. I would like a copy of your proceedure also. Could it or a modification of it be used to figure out if you have a Crane Cam? Thanks, George
George Butz

This is a very public THANK YOU to our friend John Scragg! He flew all the way from France just to help me adjust my tappets! Well, not really :-)) But he did come over and do it :-)

John had visited on his last trip to Texas and suggested, after listening to my engine, that I adjust the tappets. Well I was involved with other projects this winter, it never got done, and also I had never done it before. John agreed to help on his next visit when I mentioned that.

Soooo, John and another fellow forum member PW Lester (who did most of the "hard" work installing my Skyhook 5-speed) arrived at the house tonight, and due to pulling my back on Tuesday I couldn't really lean over the engine without support and handle the screwdriver and spanner simultaneously. So, instead of talking me through it, John, the true gentleman that he is, did it all!

All I can say, other than a giant thank you to John, is that the car never sounded better, especially at RPM above idle. So smooth and quiet at idle and when reved (well as quiet a an XPAG can be).

John's efforts is a reflection of what this forum is all about. I have never received so much support from any other forum or group as this one. So thanks to all of you who have put up with my questions over the years and provided assistance, and again my thanks to John.

Larry Karpman

This thread was discussed between 03/03/2010 and 12/03/2010

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