[Fot] Cam Timing Degree Specs

[Richard Good]

Glenn,

The timing specs for the late TR6 cam are:

Intake open 18 deg BTDC, close 58 deg ABDC
Exhaust open 58 deg BBDC, close 18 deg ATDC

I believe these timing specs are supposed to be point of opening/closing. 
If that is the case, with valve clearance spec of .010" at the valve, the 
tappet has to move .010" divided by rocker ratio of 1.45:1 = .007" before 
the valve starts opening.  So you should be able to time to these specs at 
.007" of tappet lift.  Stock cams I have checked appear to have this 
advertised duration at about .010" tappet lift so you may have to go to 
.010" to get these timing points to hold out.

I have never seen .050" timing specs for the stock cam but the ones I have 
checked appear to have about 210 deg duration at .050" so the timing specs 
would be:

Intake open 5 deg ATDC, close 35 deg ABDC
Exhaust open 35 deg BBDC, close 5 deg BTDC

Regards,
Richard Good
Good Parts Inc.

--------------------------------------------------
From: "Glenn Franco" <gaf3 at charter.net>
Sent: Tuesday, May 31, 2011 3:05 PM
To: "Friends of triumph" <fot at autox.team.net>; <6pack at autox.team.net>
Subject: [Fot] Cam Timing Degree Specs

> Hi
> I putting a late model 74 TR6 back together after a rebuild.
> I'm attempting to time the cam. This one has no marks on the gears since 
> it had been replaced.
> I have the degree wheel set up but I'm having difficulty finding the cam 
> specs for a stock TR6 Cam?
> And if found what amount of lift does the specs relate to (.050"??) on 
> this engine.
> Can anyone out there point me in the right direction.
> The head has not been installed and I have the degree wheel set and the 
> dial indicator taking measurements off the pushrod.
> Thanks in advance
> Glenn