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MG TD TF 1500 - Flywheel TDC Marks
|Anybody know where/if there are TDC marks & what they look like on the flywheel & block on an early TD? I know where they are on the timing chain cover & crank pulley. There is some info in the archive on this but it is not at all clear. As I'm attemting to ascertain the timing of the existing cam prior to fitting the cam with the roller lifters, once the timing cover is removed, I've lost my point of reference. The flywheel/engine marks would be a useful cross check on my determined TDC. I would also be very interested to hear from anyone who has installed such a cam themselves as I have had very little timing & installation information from the supplier. Cheers|
Peter TD 5801
It's no different than any other camshaft. Check your manual... line up the painted teeth with the marks on your timing gears..
If your head is off, a dial indicator on the piston will give you TDC. If the head is on, use a piston stop with a degree wheel.
There are a ton of video's on youtube about degree'ing a camshaft.
|Thanks Blair, I'm up to speed on the original timing method, however the question still remains, are there timing marks on the flywheel? If so where are they & what do they look like? The days are long gone since timing chains had bright links & the original timing gears don't have painted teeth, just the inscribed letter T. The timing for the cam with the roller lifters is nothing like either of the originals. |
Peter TD 5801
|Peter, no timing marks on flywheel that I'm aware of.|
As for cam timing, I find TDC on the engine by measuring a known value of the piston down on either side, and then selecting the middle point. I put an accurate pointer on the engine at that point. The flywheel would be fine if you have access to it.
I install the gears and chain, and keep tension on the driven side. With no chain markings, I just make sure I have the proper number of links between the timing marks on the gears. I install the degree wheel based on TDC I identified.
Then, I take the cam card and determine the full opening point of the first lifter. I find that point by going .050 either side and splitting the difference if it is a symmetrical lobe cam, or if they give the point that both lifters are supposed to have exactly equal clearance I use that after setting a large gap on both base circles.
I spin the engine several times checking the max and keeping tension on the driven side. If I am off, I order an offset key. There are also vernier cams available, which allow you to turn the cam shaft to the correct lift and lock it down.
Mark the gears.
If this all sounds like fun, the Triumph 1500 engine (also used as a midget engine from 1975 to 1979) the timing gear is attached with two offset bolts, and consists of turning the cam gear 90 degrees for 1/2 tooth, and flipping it front to back for 1/4 tooth. 3/4 tooth requires turning and flipping, after which if you still have your wits about you, mark the gears. I actually mark these gears with a sharpie before I start, to make retuning to the starting point if needed, possible.
I hope this helps,
|Thanks Dave. Unfortunately a Timing Card was not supplied with the cam. I have bits of information & am aware of a variety of ways to degree a cam using both a degree wheel & a dial gauge & even how to proceed with no degree wheel or dial gauge, using just a set of feeler gauges. I do have some valve data which I can use to check the cam once installed. If I find I require one, where do you order an offset key from? The local suppliers here are unable to help. I'm glad I don't own a Triumph! Cheers|
Peter TD 5801
This thread was discussed between 27/05/2014 and 28/05/2014
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