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XPAG CAMS AND TIMING

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Suntea4two Bob Rosa
Kawkawlin, MI, USA   USA
1953 MG TD
1953 MG TD
Gents, Over the past two weeks, I've been trying to learn how to read my 53 TD cam and also compare it to the cam profile in the Schach manual and the attached Moss cam. Based on the cam card I tried to draw the profile the best I understood the information. I am sure I must have a mistake or two. Could sure use your help to correct my drawing and also learn from my mistakes. Thanks!

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Paul J Avatar
Locust Grove, OK, USA   USA
Maybe Len Fanelli will chime in, he's a cam expert. If I ever need to rebuild my engine, his roller cam will go in it. thumbs up PJ

crankjournal Avatar
crankjournal Len Fanelli
Yonkers, NY, USA   USA
Thanks PJ!
Bob your diagram looks correct, do you have this cam in your engine?
The OEM cam (.019" valve lash) has 248 / 256 degrees duration using a checking clearance of .019" & .315" gross valve lift.
The cam timing using .050" lifter rise is used much more to determine more accurately how the cam compares, along with lobe separation angle and when the intake valve closes.
Hope this helps!
Len

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plus4moggie Tom Lange
Bar Harbor, ME, USA   USA
I remember the numbers differently - I have written down in my notes (from FR Millmore) that the early cam used up to eng TD2/24115 with .019 running clearance, had the Inlet open at 11 degrees before TDC, and close 57 degrees after BDC; the exhaust opens at 52 degrees before BDC, and closes at 24 degrees after TDC.

The later cam used from engine TD2/24116, with .012 running clearance, had the inlet open at 5 degrees before TDC and close at 45 degrees after BDC; the exhaust opens at 45 degrees before BDC, closes at 5 degrees after TDC.

Tom Lange
MGT Repair

crankjournal Avatar
crankjournal Len Fanelli
Yonkers, NY, USA   USA
Thanks Tom, The diagram is for the Crane 340-0010 performance cam, Inlet open at 11 degrees before TDC, and close 57 degrees after BDC; the exhaust opens at 52 degrees before BDC, and closes at 24 degrees after TDC, Intake 11+57 + 180 = 248, Exhaust 52+24 + 180= 256.
Yes, the later stock cam has 230 degrees duration.
I would like to see the timing / duration of a stock cam @ .050" lifter rise. I may get around to it !
The stock Crane replacement blue printed 340-0002 cam, 242 degrees advertised duration, it is not a stock profile.
Hope this makes sense.
Len

Suntea4two Bob Rosa
Kawkawlin, MI, USA   USA
1953 MG TD
1953 MG TD
Great information Guys. I'm very glad to see all this information. Thanks!!! Len and all, here is my dilemma. I purchased my 53 TD with no engine, trans and all items attached to them. Struggled for 20 years trying to find a engine I could afford. Completely rebuilt the car from the ground up, all new four corner sheet metal etc. So finally I met a guy whom had taken a short block in on a trade for work he'd done and sold it to me at a fair price. Short block is totally unknown. Cam in it unknown. Don't want to admit my stupidity but I accidentally ran for a very short time dry when I could not get it to prime. So because I'm a 14 yr retired welding engineer and my mind wants to know all the detailed information on this engine. I did have it running for a period of time when I had 40 oil pressure. Ran fairly nicely but would back fire thru carbs. So next I had a coil that went bad. Was original to car. All these bad things have happened before I could do the timing light thing to get that right. If you have been reading my other post, I sized a wrist pin to piston. May all be fixed on that end of things now but I still have a mystery cam. So I'm trying to learn enough to figure it out. If I am reading my dial indicator correctly, I only have about .205 of lift on this cam. Sounds like I may need to get one of Len's also. OH. The cam data I plotted is not my cam. Belongs to another one of this great blogs members who is trying to help me get back running. His cam data and all the good information you'll have provided here is my next drawing assignment. Looks like it may get above thirty degrees here tomorrow, so I'm going to get a helper and run my cam data again. There is more to this story then I want to bore you with when it comes to the cam. Also making a movie of doing it to add to this blog. There may be past blog info out there, but I seem to also have a problem getting the search to get me there. THANKS!!!

crankjournal Avatar
crankjournal Len Fanelli
Yonkers, NY, USA   USA
Bob, we are ALL glad to help! That is why we are here! " MG the marque of friendship"!!
L

Suntea4two Bob Rosa
Kawkawlin, MI, USA   USA
1953 MG TD
1953 MG TD
Hi Gents. I drew up the early cam profile today based on the good info Tom gave us. Plus I know my short block is of the early type based on the distributor locking pin. I'll have to get the numbers off of it tomorrow. So I am guessing it is an early cam in it. My set up as of right now. My helper for tomorrow is a good engine man so I need his eyes to verify the degree readings we get. Will post results in evening if I can. Thanks!


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Suntea4two Bob Rosa
Kawkawlin, MI, USA   USA
1953 MG TD
1953 MG TD
Looks like I sent the wrong photo. Try this one.


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Suntea4two Bob Rosa
Kawkawlin, MI, USA   USA
1953 MG TD
1953 MG TD
Hi Gents. We ran the cam profile again today and concluded that I have a badly worn cam. We verified that I only had .205 inch lift at the lifter when It should be closer to .315 inch. I did make a movie of the dial indicator checking this info. We ran the open close sequence about 4 times for exhaust and intake and found we had excessive duration, like 350 degrees. This long duration started to make sens when you think in terms of the cam lobe being worn down so much as it appears to be. We had the timing set up with both sprockets at 12 and the 13 / 15 links. I got the number off of my brass tag and it is 17365. There was also a cast number on the block of 24445. Not sure if that cast number means anything. Now I need to decide if I want NOS cam or one of Len's rollers. I'm also going to stop by a local engine shop and get a quote to go thru the short block and document all the dimensions vs. spec. May even have to have them boil the block and put in some new cam bearings. Thanks! Bob

TD4834 Avatar
TD4834 Bill Chasser
Sacramento, CA, USA   USA
1950 MG TD
1951 MG TD MkII
.205 at the lifter gives you .307 at the valve. What flat tappet cam are you running? My roller cam has .430 advertised lift at the valve.



Bill Chasser
TD-4834
TD/c-8151
TD/c-16920
TD-19408
TD-24060



Edited 1 time(s). Last edit at 2019-01-23 03:38 PM by TD4834.

Suntea4two Bob Rosa
Kawkawlin, MI, USA   USA
1953 MG TD
1953 MG TD
I'm with you Bill on that. Please note on the cam card above they spec cam lift of .280 / .294 and valve lift respectively of .420 / .441inch. We ran the lift at the lifter as many as twenty times, just because we could not believe it was so low. I have a hard time believing this cam would provide much power when driven. I got the .315 inch from the manual and it does say valve lift. Can you understand the long duration's we were seeing on both exhaust and intake valve. I checked this about six times last week and we did it again 4 times today. I wanted to try and make a movie of doing this and it was difficult to do with one's body in the way when trying to read and turn the crank dial. Us over 70 guys have to get close to see good. LOL Thanks! Bob

TD4834 Avatar
TD4834 Bill Chasser
Sacramento, CA, USA   USA
1950 MG TD
1951 MG TD MkII
Bob, Len’s comments above are correct regarding checking cam specs. I’m not familiar with Cranes offerings. and have not seen their cams firsthand. I’ve only seen pics in the Moss catalogs. I suspect though that they are a billet cam just as Len’s Andrews cams. They will have a machined surface across the entire stick versus a cast cam with rough as cast surfaces between the lobes and bearing surfaces. I say this as possibly a way to determine whether you indeed have a modern aftermarket camshaft installed. Though side by side cam comparison above would appear to be a stock profile and a roller profile it also shows the difference between a cast (lt) vs a billet (rt) construction.

Not to change the subject but with the lift posted on the Crane cam spec card you will also need to be checking valve to piston and valve to cylinder wall clearances. If you have a shaved head or pop up designed pistons this is an important consideration that needs to be addressed as well.



Bill Chasser
TD-4834
TD/c-8151
TD/c-16920
TD-19408
TD-24060

LaVerne Avatar
LaVerne LaVerne Downey
Fruita, CO, USA   USA
1954 MG TF "Green Hornet"
1969 MG MGB
1979 Triumph TR8 "Wedgie"
Valve to piston clearance isn't an issue with stock pistons unless you have some truely exotic racing cam.....exhaust valve to engine deck is however something that needs to be checked with any cam that has lift more than stock or a head that has been shaved a great deal.

TD4834 Avatar
TD4834 Bill Chasser
Sacramento, CA, USA   USA
1950 MG TD
1951 MG TD MkII
LaVerne you are correct. Note that I did say “pop up pistons” to raise compression which I do have in TD-4834. Just trying to cover all of the bases for others contemplating high lift cams. When using non OEM spec’s all items need to be considered



Bill Chasser
TD-4834
TD/c-8151
TD/c-16920
TD-19408
TD-24060

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