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MG TD TF 1500 - Recognising camshafts

Hi T-Typers.

Image attached of a TF cam (actually from Wolseley 4/44), a TC cam and a "factory full-race" 168551 cam comparing the lobe shape and overlap. "TF" cam on left has sharp lobes. TC cam in centre has broader, more rounded lobes. 1678551 cam on right had very broad, rounded lobes. If you imagine followers sitting on the rearmost two lobes, you will see that the valve overlap increases from left to right.

I am interested to hear if any other T-Type "tinkerers" have noticed the markings on the back of some XPAG camshafts. I was lucky to have a dad who bought lots of spare (mainly TC) XPAG bits in the late 60s and early 70s. I noticed that every original TC camshaft I saw had TWO machined rings on the back of the shaft. Some other shafts, I think from Morris 10s, had ONE machined ring. The latter had sharper lobes. Some of us in South Australia even started calling camshafts "one ring" or "two ring" cams. For some time I mistakenly thought the later TD/TF cams also had one ring but I now realise TF/Wolseley-4/44 cams probably have no rings. The Wolseley cam is said to be the same as the late TD/TF .... i.e. same timing as Morris 10 but with more lift. I have seen one factory AEG122 and about six 168551s and none of them had machined rings.

Please comment if you have any information which associates the rings on the back of the shaft with their origin. Markings might not have changed when the cam changed but it appears to me that Morris 10 perhaps had one ring, TC had two rings and later cams had no rings.

Bob Schapel

R L Schapel

A second image from a steeper angle. Sorry about the black sludge on the cams ... leaving it there prevents rust!
Bob

R L Schapel

Here are photos of cam that came out of a very early TD engine.

Len Fanelli

Bob
I have a camshaft on my shelf identical to the middle one in your photo. I think, but cannot be sure, that it came from a Morris 10 block that I recently parted with.
Peter (TC9356)
Peter Malkin

Bob
The full race cam pictured sure looks like it has it's fair share of duration/lift
Roughly , if you don't mind, what would the specs of that cam be --just roughly--just out of interest
thanks
willy
William Revit

Thanks Len. That is a good angle and shows the sharper lobe shape and no rings like the later one on the left in my photos. Assuming it has not been reground, I reckon it is the later cam.

Peter, Does your cam have the same lobe shape AND machined rings as my centre cam? A photo from the rear would be good but only if easy.

William, The "full race" cam is the factory 168551 and is basically a 60/30 cam (To be exact .. Inlet opens 32 BTDC, closes 58 ABDC. Exhaust opens 60 BBDC closes 30 ATDC) By modern standards it is quite "mild" to be called "full race".

Thanks for the feedback.
Bob
R L Schapel

Cheers Bob
Interesting- Just looking at it you would think it was way bigger than that-----tricked again
willy
William Revit

Bob
End shot of camshaft as requested.
Peter (TC9356)

Peter Malkin

Bob
and other end.
Peter (TC9356)

Peter Malkin

Thanks Peter,
Great. That fits perfectly with my theory! Your cam has the sharper lobes and has ONE ring machined in the rear. According to your information AND my theory, it is a Morris 10 cam.

I guess I need a lot of feedback about certified TC and Morris 10 cams to verify what we have believed in South Australia for about 40 years. It is a pity that all cams from late TD (whether standard, half race or full race) seem to have no markings. Of course it is possible that the markings (rings) on Morris 10 and TC cams did not change at the exact time the cam timing changed.

I can't remember where I saw a part number stamped into a cam but I have seen ONE. I think it was an AEG122 (half race) cam.

I have a TC cam, TF cam (Wolseley 4/44) , AEG122 cam, and 168551 cam. When I have got all the feedback I can get, I plan on summarising it in a new thread. I think that it should help T-Typers recognise original cams (unless reground).

Including Morris 10 cams, are there any FACTORY cams apart from the five mentioned here?

Bob
R L Schapel

The camshaft used in the TB, TC and most of the TD was the MG862/171 - it was also used in the YT.
The late TD, TF and W4/44 was the 168553.
The Y started with the MG900/106 cam, but this was modified and became the X22329 cam, which was continued into the early YB. The later YB used the 168553 cam.
All this information is available in the workshop manuals and parts lists.

The AEG122 cam is similar to the MG862/171. If anyone gets offered a 168551 cam, I would not recommend buying it.
R A WILSON

Thanks for that information R.A.

I should put part numbers to the different cams. It is a pity the numbers are rarely stamped into the cams. I must look at the similarity between the MG900/106 cam and the Morris 10 cam. I am guessing they might be the same or very similar. The X22329 is a new one to me, so thanks for that also.

Yes, the AEG122 ("half race" for TF) is not very different from the standard TC cam. Your comment on the 168551 is interesting. I have had one in my road TC for 47 years and others in my supercharged race TC for 45 years. Both have performed very well.

Great to get the feedback ..... There is always something new to learn!

Bob
R L Schapel

The Morris Ten-Four series M used the X22329 cam.
R A WILSON

Should have mentioned, MG changed their part numbering system twice, so some parts had later numbers.
Camshaft numbers are as follows.
MG862/171 - X24084 - AAA5576, TB,TC,YT,early TD.
MG900/106, early Y, discontinued.
X22329 - AAA5594, late Y,early YB,M10-4/M.
168553 - AAA3096, late TD,TF,late YB,W4/44.
AEG122. 1/2 race.
168551, full race, discontinued.
R A WILSON

Thanks again R A,
The various forms of the 5/45-45/5 cam, due to minor changes, certainly complicates the issue!

Peter,
If you get time, could you measure the cam lift (NOT corrected with rocker ratio) of that "one ring" Morris 10 cam of yours? That is the height of the lobe above the base circle.

Perhaps I will put a post on the Y-Type (and TC) page to ask for similar information. It will be interesting to see if anyone can provide evidence that the late Y and early YB cams had that "one ring" on the rear!

Bob Schapel
R L Schapel

A second photo of the same cam

Len Fanelli

Thanks Len,
The sharper looking profile of a later cam with no rings fits my theory. In your photos the circlip being removed helps a clear view of the lobe shape. I have often wondered about the purpose of the circlip. I can only guess that it assisted fitting the rear cam bearing.
Bob
R L Schapel

Bob when installing the cam & sprocket, the circlip is to stop the camshaft at the rear cam bearing, and not let it hit the core plug.
Oh BTW I recently had a center cam bearing that had the 2 pin holes, to turn the bearing, installed on the REAR of the bearing! It had to be put in "backwards" for the lube holes to line up!
Len Fanelli

Bob
As best I can measure with my elcheapo electronic calipers the crest of the lobe sits 5.87mm above the outer diameter of the shaft. If you like I can mic it up tonight and get a more accurate figure.
Peter (TC9356)
Peter Malkin

Thanks Len,
That explains what used to intrigue me.

Thanks Peter,
That measurement is near enough.

Bob
R L Schapel

Peter,
5.87mm is more lobe height than I would expect from a Morris 10. Do you mean that the crest of the lobe is that distance above the base circle of the cam lobe or the crest is that distance above the rest of the shaft (rough, unground area). The former is the critical measurement.

I just measured 5.6mm, 5.4mm and 5.5mm lobe heights on an almost unused 168551, an unused AEG122 and a Wolseley 4/44 respectively.

Bob
R L Schapel

Thought I'd provide extra data. The mm is the valve lift (cam lift x rocker ratio - tappet clearance), the " is tappet clearance hot.

TB,TC,YT,early TD = MG862/171 - X24084 - AAA5576 ; 11/57/52/24/8mm/.019"
Early Y = MG900/106 ; 11/57/52/24/6.5mm/.019"
Late Y,early YB,M10-4/M = X22329 - AAA5594 ; 5/45/45/5/8mm/.019"
Late TD,TF,late YB,W4/44 = 168553 - AAA3096 ; 5/45/45/5/8.3mm/.012"
Half race = AEG122 ; 13/59/50/22/8mm/.019",.015" for quietness
Full race = 168551 ; 32/58/60/30/8mm/inlet.012",exhaust.019"

(I hope I haven't included any errors - I have checked it four times)

Also, calculating the valve lift for the four lobe heights above, I obtain;
M10, lobe = 5.87mm, in/ex = 8.3mm
168551, lobe = 5.6mm, inlet = 8.1mm, exhaust = 7.9mm.
AEG122, lobe = 5.4mm, in/ex = 7.6mm, in/ex quiet = 7.7mm
W4/44, lobe = 5.5mm, in/ex = 7.95mm

R A WILSON

That's great R A,
You have summarised and calculated well! Measured lift matches nominal lift on the 168551. The Wolseley cam seems a bit short as it might have a bit of wear. However, my AEG122 is unused and I am surprised it appears .4mm short. The Morris 10 cam has more lift than expected unless it was measured differently or somehow found its way from a later car. Peter inferred he should re-measure with another device.

Tanks for the feedback!
Bob
R L Schapel

Oh dear, I have just found a leaflet, issued in 2001, from Merton Motorsport, a UK company that used to supply T type camshafts. The leaflet shows the valve lift of the AEG122 and 168551 camshafts to be 8.3mm. I found it difficult to find those valve lifts in any company literature, so I relied on articles written at the time, which mention 8mm. The Merton Motorsport leaflet lists the other T type camshafts, and the data matches mine, which came from company workshop manuals, tuning booklets and parts lists, and 1950's Motor Trader publications - this also applies to my Y, W and M data.

It may be that quoted valve lift ignores the tappet clearance **, so just applying the rocker ratio of 1.5:1 to the four lobe heights;
M10, 5.87mm, lift 8.8mm ??
168551, 5.6mm, lift 8.4mm (close to the 8.3mm - possible remeasure?)
AEG122, 5.4mm, lift 8.1mm (could be 8.3mm worn)
W4/44, 5.5mm, lift 8.25mm

Don't know whether it helps or hinders !
**This does not affect the cam data, which specifies valve lift rather than cam lift.
R A WILSON

Bob
My initial measurement was from the unground area - my bad.
I have measured again just using vernier calipers with the following results:
Base Circle Diameter 23.75mm
Exhaust Valve Lobe Height #1 5.22mm
#2 5.09mm
#3 4.97mm
#4 5.28mm
Inlet Valve Lobe Height #1 5.00mm
#2 5.16mm
#3 5.16mm
#4 5.13mm
I am a novice with respect to cam shafts - hope that I have measured correctly. Obviously the cam in question has had some use!!
Peter (TC9356)
Peter Malkin

Thank you R A and Peter,

R A,
Yes that helps a lot .... and your calculations have saved me a lot of maths. Yes, I agree that lift was probably nominal without valve clearance. My AEG122 cam has not ever been run, so that is a mystery unless it is a new TC cam in AEG122 packing. Unlikely considering its history. I will have to check that out. I have seen a variety of rocker ratios quoted. Measuring seems to verify your 1.5 ratio. Is 1.5 the generally accepted ratio?

Peter,
Thank you for that. The measurement now seems to match what it should be according to R A's formula. I thought Morris 10 would have 4.35mm lobe height to give the 6.5mm valve lift. Your cam looks to be the late YA/early YB type. Perhaps later Morris 10s also had this cam .... The plot thickens!

Bob

R L Schapel

Regarding rocker ratio, it is mentioned in company data somewhere, but it was also given on the data sheets when you bought a Crane camshaft - which I did many years ago. Out of curiosity I did check by taking measurements from engine section drawings and measuring actual parts - all confirming 1.5:1.
Re your AEG122 - 5.53mm lobes would be better - do all eight lobes measure the same ?
R A WILSON

Yes R A,
I now have measured ALL the AEG122 lobes more carefully and lift appears to be 5.5mm. I still only used a vernier caliper but probably should have used a micrometer right from the start .... my micrometers are all in inches! Now it makes more sense and fits your prediction. Thanks for the motivation to check.

I would still like to see more info' and photos of cams with ONE ring machined into their rear end. Peter Malkin's is the only response I have had on that issue. All other information I have about ONE ring cams is in my (faded) memory from about 45 years ago .... and needs refreshing!

Bob

R L Schapel

This thread was discussed between 11/05/2016 and 22/05/2016

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