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MG TD TF 1500 - Engine experts- help

Is it possible to tell from this picture if the cam is timed correctly?
I took this picture when the machine shop was assembling my TD engine.
Months later, I finally have the engine installed and decided to verify which camshaft I had using the procedure described by Dave DuBose as found in Ttalk . After several tries I am unable to see the intake valve opening anytime before TDC - more like 10 ATDC. So maybe I'm doing something wrong, or maybe the timing chain is not correctly installed. I don't want to tear the front of the car apart if I don't have to, so any help will be appreciated.

B Mooney

Please forgive but this may seem obvious. Have you adjusted the valves?
JWP Policastro

I cannot see the marks on your photo.
The easiest way is to locate the dots on both gears. When installed correctly they will form a direct line from the center of the crankshaft to the centerline of the cam gear.
Some of the timing chains had special marks on the side of the links . This sometimes created a problem as they told you how to do it yet they showed the photo upside down. It lead to many cams being way off timing.
Center of crankshaft. dot on crank gear-dot on cam gear and centerline of camshaft all in a straight line is the required position.
Sandy
fm melling

You can check the timing without major dismantling by removing the rocker cover and setting up a dial indicator to show when valves are just about to open and close. You then need to make a protractor that is a good fit over the starting handle shaft. Turn the engine over with the handle until the pulley shows TDC and set the protractor to zero against a pointer fixed to the bumper bar. The engine can then be turned over on the handle and the opening and closing degrees noted from the protractor. It is important to keep clockwise pressure on the handle at all times. I realise the above is not too explicit but if you understand how an engine works it could save you needlessly dismantling the front of the car.

Jan T
J Targosz

This is the method I am using:

http://www.ttalk.info/CamshaftID.htm

I don't have a dial indicator although I could get one if necessary.
B Mooney

Without a photo taken like this when the gear set and chain were installed it would be very difficult to determine. Once the crank has been turned it takes a larger number of revolutions to get them matched back up again.

L E D LaVerne

The lift after TDC isn't a huge concern depending on the cam installed. As you can see on my cam there is only .050 at 7* BTDC and the peak comes well after. A stock type grind may well not have any lift until after TDC

L E D LaVerne

The number of links between the white marks on the chain does give me some cause for concern though.
L E D LaVerne

Very difficult to determine with your pic. If the pic was straight on you would be able to see all the marks necessary to determine this. Blowers WSM shows a very detailed picture of the correct orientation but I don't have the book near me to take pic.
W A Chasser

Pretty clear illustration in the WSM, the same as the one on p 119 of Blower. Agree with the orientation of the block (upside down) causing issues. If the white marks are both on the right hand side of your pic then something isn't right. Jan's suggestion is a good one. Dial indicators are very easily made. Just Google, download & print then paste onto a piece of cardboard for rigidity. I could be wrong but from memory it takes 16 rotations of the engine to get the marks to correctly align again. Cheers
Peter TD 5801
P Hehir

I know the photo was from before the engine was finished, but in addition to the cam question, I would be leery of using cotter pins on the main studs, as opposed to lock-wiring them in place. If the studs have not been properly tightened in the block, the studs and nuts can come unscrewed when cotter pins are used.

I also strongly recommend using lockwire on the chain tensioner bolts, as original - this may already have been done, but how do you know?

You might want to re-check everything the shop has done, as it seems to me there are too many questions...

Tom Lange
MGT Repair
t lange

OK :-)


L E D LaVerne

It has been timed with 13 ROLLERS not LINKS between timing marks.
If you download the pic and blow up it is plain to see.
Ray TF 2884
Ray Lee

With about any cam, the intake should start opening just before TDC, and the exhaust fully closes just after TDC. Just watch the rocker arms, no need for a dial indicator for a gross check. Make sure you are looking into the sparkplug hole to verify TDC, rather than a mark on the pulley as some pulleys have two notches/marks- one of which is not at TDC. Dave's info is great, but that is only useful for factory cams. Crane had proprietary cams years ago in the late 80's, and even regrinds will likely not be the same as original. IMHO, the picture is useless as there is no way to know if it is at TDC or any marks are aligned. Although I don't see any "bright" links on your chain, there was one around here some years ago that were not spaced as original. You have to count links. George
George Butz

At TDC both keyways should be at the 12 o'clock position.
in the photo both the keyways are at about 10 mins to ( the cam keyway is where the sprag of the lock washer fits). If crank is rotated till the keyway is at 12 o'clock the cam keyway is at about 5 mins to because of the 2 to 1 gear ratio, making the cam late in opening as described.
Ray TF 2884
Ray Lee

I agree with Ray that the white marks on your chain indicate 13 rollers instead of links.

My picture is also useless for your timing purposes, but it does show the 13 links in between.

Does/did the engine run after overhauling?


Willem van der Veer

A common trap is to time the XPAG whilst it is inverted, not the case here however something to be aware of.
G Evans

Thanks for all the input. You have helped me accept that I have to go in and reset the timing chain. At least I haven't yet filled the cooling system or the sump - so that's good. I'm sure glad I tried to determine which cam I had before adjusting the valves. Otherwise I would have had a lot more car to disassemble to make it right.

B Mooney

LaVerne's comment& my response got me to thinking about just how many revolutions it does take for the marks to align again. I googled the question & stumbled into some serious maths.. So I'm starting another thread where I'll pose the question. Cheers
Peter TD 5801
P Hehir


Peter, The WSM Section A.21 says it takes 20 Turns to get the marks lined up again.
However Peter, I've never actually turned an engine 20 times to confirm what the WSM says.
Richard Cameron

I have opened up the front of the engine and can see that the cam is not timed correctly. There are 12 links between the timing marks instead of 13. In the picture I have put arrows on the timing marks.
My problem now is how to get the sprockets off the crank and cam. The wsm says to lever them off or use 2 of the special tools designed for this purpose. I have tried levering but I am afraid of damaging the chain. There isn't enough room to use a generic puller.
Any advice on how to proceed?

B Mooney

B Mooney and others - the procedure that I provided on TTalk was never intended to align the cam/crank shaft. The purpose of the procedure was a quick check as to which of the two cam shafts that were ORIGINALLY in the engine. The check is in no way, intended to align the cam and crank shaft - that is covered in the shop manual. It is also done on an engine that has not been disassembled. By now, unless the car was resurrected, untouched in the past thirty years, the only original camshaft would most likely be the later of the two camshafts. Cheers - Dave
D.W. DuBois

B, the levering is done very slowly, pulley by pulley. As long as the pulleys are still aligned they can be slid off together. It'll be the classic 'opposite of the way in which they were installed'. Don't expect any significant amount of movement. When you get a movement in one of them go to the other one. Bud
Bud Krueger


Spray both sprocket/shafts with liquid wrench because they are probably stuck because they may not have been cleaned very well from the looks if it. Just use two big screw drivers--- one on each side and pry them forward. A piece of cardboard can be used to protect some. They both have to come forward together a little at a time or they will bind with the timing chain in place.

The pressure needs to be off of the valve train so the cam will turn freely for setting timing marks.
Richard Cameron


Not trying to be critical here of previous work, but I would like to add a further comment. I've been through this process myself many times and I've found that it really helps to clean the sprockets and shafts really well after you get them off. Look for burrs and clean them up well with fine grit wet/ dry sandpaper or a file if necessary. This will make reassembly much easier when your trying to align everything.

Also, before you reinstall the chain tensioner, inspect it carefully--- I found that 3 out of 5 of mine had the pressure port oil hole plugged with dirt/grime. This hole is smaller than a common straight pin so you can see it is possible for sludge to block its port. Obviously the tensioner won't work if is blocked.
Richard Cameron

I got the sprockets off a few days ago. Thanks for all the input. I tried big screwdrivers but wasn't getting anywhere. Then I remembered the tire levers (Dunlop) in the tool roll. They worked perfectly. Just thick enough, stiff enough, long enough and with a nice profile. The width spread the load to reduce the chance of damaging the chain or any thing else.
B Mooney

here are the levers

B Mooney

This thread was discussed between 11/05/2017 and 31/05/2017

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