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MikeH

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Hi All, When the engine is at #1 TDC, where should the rotor be pointing? Thanks, Mike

71 MGB OD & Wires
63 TR4 Surrey Top
 
at the position of the # 1 plug wire on the distributer cap.

Paul
 
That's not quite true I think. When both #4 valves are open and both #1 valves are closed then continue turning engine till notch in the crankshaft pully in in line with the correct timing pointer, at that time the roter should be pointed toward #1 segment of the distributor cap.
 
Thanks, What I mean is that on Triumph's #1 TDC the rotor points to #1 pushrod. This is to check distributer to cam timing. What is it on MGB's? Mike

71 MGB OD & Wires
63 TR4 Surrey Top
 
Jack,
when the timing pointer is in line with the correct notch on the crankshaft pulley, THAT is TDC. And when it is at this position then the roter is pointing at the # 1 plug wire position on the cap.
How is my answer untrue then? I said the same thing that you did.

checking the position of the # 4 and #1 valves just assures you that the engine is on the proper compression stroke, so you are not 180 degrees out on the timing.


Paul
 
Guess is that darn language thing again. Note I said "That's not quite true I think". I was not quite sure I understood exactly what you said so I added a bit for old folks. LOL I am the old folks in this case. Yes to what you said just above. Different words, same answer I think.

Nothing more a pain than having things 180 out when you try to fire it first time. Check check check cause boy I can screw this up easly therefor the waste of words on my part.
 
Paul, What I'm trying to find out, is which position on the cap is the #1 Plug wire? Thanks, Mike

71 MGB OD & Wires
63 TR4 Surrey Top
 
[ QUOTE ]
which position on the cap is the #1 Plug wire?

[/ QUOTE ]

When all above is in alignment, whichever plug wire the rotor is facing becomes the #1 plug....but make sure you're actually on #1 TDC - there are several ways to check that:

timing marks; finger over open spark plug hole to feel air push agaist it; small screwdriver in spark plug hole to see it moves up or down as you turn engine over are just a few.
Oh, it usually comes out to be the hole nearest #1 plug (i.e., bisecting a line from the center of the rotor & the #1 plug hole)
 
In addition to what Tony said, it is general pracice to install the distributor so that the #1 plug wire terminal is the one closest to the #1 cylinder. that means that if you pull the distributor cap, while the engine is at TDC on #1 compression stroke, the rotor will be pointing at the #1 cylinder. You can install it any way you like, but that's the common practice.
Hope this helps not confuses
 
I always managed to believe on faith the #1 position was at a "One O'clock" position at the diz. When assembling an engine and installing the dizzy drive according to the factory manual it works out that way. If (and in forty-odd years it could) someone has been in there to install the dizzy drive "dog" in a ~funny~ position then it could be *anyplace*! A dial indicator and some judicious knobbling can suss out where it -really- is in relation to the #1 piston though.
 
Am I correct in that for setting the dizzy, the #1 piston would be all the way up and the #4 all the way down with the timeing mark on the dampner at 7 degrees? Now the roter should point at the front wire, about at the #1 plug in fact?
The reason, of course, that I ask is that engine is out and I wish to make sure it is not 180 out. Do I remember correctly or am I all wet?

Associated question and what brings this up is that puts the vacuem advance on the Dizzy at a strange angle unless and maybe I dis remember, there was a rubber angle peice attached to the Dizzy vacuem fitting that corrects for that strange placement? LOL and it is Moss # 153-840 however your commens per the above might let me sleep better.
 
The #1 and #4 pistons are BOTH at TDC on the crank, Jack. 2 and 3 are at BDC. Hence the 1-3-4-2 firing order. Alternating four-stroke balance. When #1 hits fire #4 is pushing exhaust out. Same with the next "pair": 3 and 2...
 
Yes Doc, agreed. Engine now sets with 1/4 at the top of the flywheel, Dizzy shaft, large half up, in place and Dizzy pointing at #1 cylinder. Of course timeing chain marks are spot on, checked maybe 5 times, hehe.

Now I know the Dizzy is not correct yet as the engine has not been advanced to 7 degrees on the crank dampner wheel mark.

However, if I did so, turn the engine, then I could preaty much set the Dizzy by eyeball to the #1 position and be preaty close for cranking, correct? Boy has it been a long time and the details seem to be a bit hazy. Yea I know use a light and catch the points just closing for a spot on setting.
 
Thanks all, That's what I needed. I assumed that correctly put together, the rotor should point in the general direction of the first cylinder at TDC, Just wanted to make sure. Mike

71 MGB OD & Wires
63 TR4 Surrey Top
 
Jack: Points just opening. Dizzy goes counter-clockwise, BTW.
 
Ahh, at 1/4 points just opening, of course, that is almost the end of the fireing with the #1 piston at the top.
 
Hi all, have discovered oilleaking around my dipstick at the gromet, have check catalogs and cannot find one to fit my 1979 mbg, any ideas, and help appreciated.
 
Crankcase should have neg. pressure. Have you checked the tubes or what ever that do that?

If so I should think that rings are suspect.
 
Do you use oil? Does black smoke come from the exhaust?

Do a wet dry compression check and see how the inards are. Make sure the breathers are clear so the pressure inside has a place to go. But a compression check is certinaly in order.
 
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