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+--- Thread: Type 65 static timing (/showthread.php?tid=451)
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Type 65 static timing - Colin Wilks - 13-11-2017
What is the static timing on a Type 65? - I assume less advanced than the 1 3/4" / 20° BTDC quoted for the 4.8:1 compression engines, but I have been unable to find the data for my engine, which is the original 65.
The '36 Ruby (C/R of 6:1) is quoted as 3/4" BTDC at the flywheel, which I reckon to be 8 degrees, so I am inclined to start there in the absence of better info.
I am new to Sevens and to manual timing on the steering wheel. I imagine my best course may well be trial and error, but I'd quite like to know where I should be starting from!
RE: Type 65 static timing - Derek Sheldon - 13-11-2017
Personally I don’t look at any of the figures given. I take out number one plug turn the engine over until TDC is achieved, having slackened off the dizzy clamp point the rotor arm at number one plug cap position. Replace cap and plug leads, turn on ignition, slowly rotate dizzy and wait for the electrical click which is quite audible. Clamp dizzy but not too tightly. Start engine and final adjust
RE: Type 65 static timing - Hedd_Jones - 13-11-2017
rightly or wrongly, every seven I've had I've timed quite simply without worrying about angles. This goes for a bog standard early coil with L/C head to a breathed on special with a lairy cam, big valves and H/C head.
Find No1 compression stroke.
Lign the timing mark up with the oil pressure take off.
Fit the dizzy and adjust so that the points are open with the rotor pointing No1, and the heel of the points are smack in the middle of the square on the dizzy cam.
I will guarantee that it will start and run. I fine tune by feel/ear. It is unusual that I have to take the dizzy out again. Usually there is more than enough range.
RE: Type 65 static timing - Colin Wilks - 13-11-2017
Maybe I am trying to turn an art into a science but, whilst I'm quite happy to get it going and work from there, it seems odd that there's no data for the 65 or the Nippy regarding compression ratio or timing when there is for other models.
RE: Type 65 static timing - NickB - 13-11-2017
Colin, Chris Goulds Guide to the Austin 65 and Nippy suggests a compression ratio of 6.73 for the 65, (although this head may have been skimmed - his words).
If you haven't got a copy yet, you'll want one!
Nick
RE: Type 65 static timing - graham - 13-11-2017
The procedure for setting static timing will depend on whether you have a manual advance/retard or auto advance distributor. For manual advance, set the lever on steering wheel to fully advanced and proceed as others have suggested above.
For auto advance the points should be set to open at TDC. "Standard" A7 engines will tolerate small timing errors and some tweaking on test runs may improve performance.
Graham
RE: Type 65 static timing - Colin Wilks - 13-11-2017
(13-11-2017, 03:22 PM)NickB Wrote: Colin, Chris Goulds Guide to the Austin 65 and Nippy suggests a compression ratio of 6.73 for the 65, (although this head may have been skimmed - his words).
If you haven't got a copy yet, you'll want one!
Nick
Hi Nick, along with the Woodrow manual, Chris Gould's guide was my first purchase - somehow page 21, "Original Specifications ..." had eluded me!
(13-11-2017, 04:42 PM)graham Wrote: The procedure for setting static timing will depend on whether you have a manual advance/retard or auto advance distributor. For manual advance, set the lever on steering wheel to fully advanced and proceed as others have suggested above.
For auto advance the points should be set to open at TDC. "Standard" A7 engines will tolerate small timing errors and some tweaking on test runs may improve performance.
Graham
Thanks Graham, as I said, I'm new to the manual timing on the steering wheel. I have to say your advice seems counter intuitive, in that I had imagined setting the car to idle at its static timing position and then manually advancing the timing from there to suit. Your proposal indicates I would only ever retard the timing from its static setting using the manual control, which I would think was unusual.
RE: Type 65 static timing - Bob Culver - 13-11-2017
Spark timing was another recurrent question on the old site and all aspects were covered using Search. But seems will need to start again.
Setting by ear is fine for experienced Seven hands familiar with the normal “performance” and the characteristic degrees of mechanical harshness of Seven engines in various states, but it is a mystery to those mainly familiar with more conventional engines. Performance must not be judged by noise.
Manual advance is a blessing in that many variables are eliminated and can experiment and immediately observe the result. Check that it is not a manual override of an auto distributor! (Convenient but confuses advice)
Unnecessary advance severely stresses the crank so should trend on the side of caution, as did Austins originally.
The original manual recommendation was 1 ¼ to 2 inches BTDC full advance but, at least for non racers, 2” is generally excessive. Even the Williams book only goes to 1 7/8 and that for revving Specials. Of course with manual advance you have the option of seldom using full advance. The manual advance range is considerable and full retard not normally used. Once underway at normal revs the range used is very small.
There were two auto distributors; both set to give about the advance above when fully advanced. Unfortunately this is not easily established. The early Ruby manual repeats the advice for previous manual distributors with the effect that myriads of auto advance engines have been set to this at normal static retard and operated or at least started with gross over advance.
The early auto is 3 dist/6 crank degree, for which ¾ to 7/8 inch static advance was recommneded, and the later for smooth 3 bearing engine was 8/16 with 0 to ½ inch static advance
One inch on the flywheel is about 11 crank degrees
For all settings final refinement on the road was suggested, but it is not easy to compare small auto adjustments. Must not judge performance from din.
Just what the actual characteristics of many worn, meddled, interchanged, auto distributors is now is anybody’s guess
RE: Type 65 static timing - Colin Wilks - 13-11-2017
Bob, thanks very much indeed for that explanation. You have confirmed my gut feel that 20° BTDC was excessive for my 65's static timing.This is my first seven and I have no feel or "ear" for the engine yet. It is a two bearing crank and I really don't want to mess up what is the original engine, so thanks for the warning about use of the manual advance and retard lever. I suspect you have also explained the two tiny nicks a previous owner has put on the steering wheel's timing mechanism, which exactly bracket the lever.
Thanks also to everyone else who has taken time to share their advice and for bearing with this novice sevener.
RE: Type 65 static timing - Ian Williams - 13-11-2017
Forget static timing other than to get the car started initially, for that TDC fully retarded will get it running, you then need to fine tune it with the engine running. If you do not have the ear and feel then use a strobe, you should be aiming for 26 to 28 degrees at around 3000rpm, every car will vary slightly, my Nippy with unmodified Speedy type engine reforms best around the latter figure but I do fine tune by ear and stopwatch. BTW 28 degrees is about 6 teeth on the flywheel