When the crank pinion is keyed onto the crankshaft, the motor is at top dead centre when the dot is at the top (i.e. being meshed with the idelr gear. Here, you should see the exhaust valve closing and the inlet opening for one of the cylinders (starting inlet stroke). and inlet and exhausr closed for the other (on compression stroke). If both valves are at peak lift (and not just a little bit open as they would be on inlet stroke tdc) you may have a keyway out, but I think it would be a lonngggg way out. Iy guess is your ok.
have you turned it thru 360 to see if anything catches?
..not easy to tell from the photo, but it DOES look like the inlet is just over peak, and the exhaust just approaching it......Sort of what I'd expect, but the other way round , and even then the inlet further before peak, and the exhaust further after.
If you've got the three keyway camwheel, which I guess you have, then each is 120 degrees. Sticking my neck out...I reckon if you backed the inlet cam to the next anti clockwise keyway, and forwarded the exhaust cam to the next keyway clockwise, that's how I would expect it to look.
Another quick sanity check is to check peak lift. depending on you cam it'll be about 102 degrees atdc for the inlet and 102 degrees btdc for the exhaust. 90 degrees is easy to guess with a spanner on the crank, See if it's just after/before 90 degrees atdc or btdc or not. This will tell you if you're a keyway out but not a tooth.
The 1966 should have come with three key cam wheels. 1. The keyway used for stock camshafts should be the one adjacent to the timing mark on the cam wheel (a small dot punched on the face of the gear between two teeth and adjacent to one of the three key ways). 2. As pointed out by Panic, the camshaft turns one half the speed of the crankshaft. For the discussion I thought it would be easier to understand if I used cam wheel degrees, not crankshaft. 3. If you were to look at the end of the camshaft and draw an imaginary line between the middle of both lobes it would go through the center of the camshaft's keyway. 4. With the intake camshaft's keyway at the cam wheel’s 120 degree position (as it is when you line up the intake cam wheel and idler timing marks) the camshaft would present one lobe facing upward and the center of this lobe would be at the cam wheel’s 300 degree position (120 degrees plus 180 degrees or 300 degrees). 5. With the exhaust camshaft's keyway at the cam wheel’s 240 degree cam wheel position (as it would be when you line up the exhaust timing marks with the center idler gear) the camshaft would present one lobe facing upward and the center of the lobe would be at the 60 degree cam wheel position. Looking from the side they form two upper legs of the letter “Y.” 6. As best as I can see from the picture both lobe's center appear to be at, or near, 0 cam wheel degrees. 7. The camshaft key is in the wrong keyway or you have not properly aligned the dots. 8. Lobe center was mentioned above, but this is a different deal. To begin with lobe center for an intake cam would be given in crankshaft degrees (95 to 110) After Top Dead Center (ATDC) and with the exhaust (95 to 110) Before Top Dead Center (BTDC). The position we are working with the intake and exhaust camshaft above, is with the crankshaft positioned at TDC. John
Does this make sense?
Who only wishes he was as smart as Panic and have that smooth gentlemanly style so prevelant in the Southern part of out United States of RF Whately. I am stuck with my practical experience and the dry New England wit passed on by generations of New England Yankees. Sorry! :rolleyes:
Re: REALLY stupid cam timing question....#87316 01/18/065:03 am01/18/065:03 am
Hmmm...sorry not explaining mesel very well again, probably to the annoyance and frustration of Panic and John. Long time since I paid any attention to timing marks.... One of my key failings in giving advice - not fully explaining some stuff I take for granted. I'm going into lurk mode (so I don't do any damage!), and letting those more eloquent give more thorough explanations, save to say that the keyways ARE 120 degeees apart, but not crankshaft degrees (see what I mean?).
Brian, nice drawing, but the lobes are not where they should be.
The intake should be rotated counter-clockwise so a line drawn from the timing dot, passing through the center of the cam wheel should split the cam lobe in half. The same would be true for the exhasut. Rotate the lobe in the picture clockwise until a line drawn from the dot, though the center of the camwheel splits the cam lobe in half.
To quote Panic, "That's not overlap - both lobes are almost full lift. On overlap both lobes would be visible almost "laying down" with intake lobe pointing back (just opening), exhaust lobe pointing forward (just closing)."
Look at a camshaft mounted to a cam wheel in your hand. With the exhaust key-way adjacent to the dot at 240 degrees the middle of the cam lobes would be at 240 degrees and 60 degrees. Your drawing shows them at 45 and 225 degrees. Thus when you look into the exhaust tappet guide block hole with your drawing, you see more of the lobe than you would if the lobe was at 60 degrees. john Figures given are for this discussion only. Although close enough for this discussion, the actual degrees will be slightly different because of the relationship between idler and cam wheel gear timing marks and the respective center lines. We are just playing with hand grenades? :rolleyes:
Re: REALLY stupid cam timing question....#87319 01/22/0612:00 am01/22/0612:00 am
According to Haynes manual page 29 your timing of the inlet pinion/shaft for a TR6 should be the dot aligned with the dash, not with the other dot. This alignment is for the T110, T120, TR5, TR6 and the 6T without the "wheel" mark (indicating there are no ramp cams installed).
The 5T, 6T, T100 and "wheel" (with ramp cams) marked types have the dots aligned for the inlet valves. When aligned the nearest (RH) inlet cam should be pointing about 45° to the rear and upward, the RH cilinder exhaust cam should be pointing 45° forward and upward, so your picture looks OK. It seems you didn't extract the pinions and used the wrong slot (there are 3 slots!)or mixed up the inlet with the exhaust camshaft, for the dots are likely opposite to the nearest cam and thus aligned as stated in f.i. John's post. Be sure you didn't mix up and always replace the part in the same spot you've removed them (cam followers/push rods!)Use a rubber band as told by Haynes to hold the tappetfollowers up, but more wisely: use the Haynes manual so your timing is correct for your model (dash/dot)and cancel out surprises. Good Luck and you're right, better be sure and safe than sorry.
Yes. On my 1967 TR6R, the dot on the inlet cam wheel lines up with the left dash on the idler (or lower dash in your pic). Your alignment on the exhaust wheel is right as is the crank, as far as I can see. On mine, the mark on the crank pinion was hidden by the nut. Dave