Piston numbering

[Robin]

Apologies if this is obvious but do you number pistons from the radiator end or the bulkhead end i.e is the piston nearest the radiator number 1?

thanks

[Adrian Cooper]

Piston/cylinder number 1 is at the radiator end of the engine.

Adrian

[NonMember]

1 hour ago, Adrian Cooper said:

Piston/cylinder number 1 is at the radiator end of the engine.

Except on Saab 99 (and some Renaults), where the engine is installed backwards. ?

The usual convention is to number from the pulley end to the flywheel end. That rule is independent of which way round the engine is fitted. On a V engine, number by the order of con-rods, so the bank that is offset slightly further from the flywheel are the odd numbers. Except that some manufacturers number their V engines differently.

[Robin]

Great - thanks guys

[Anglefire]

Off topic slightly, but the Land Rover TDV6 engine numbering is conventional, but the injectors into the cylinders is different! Just to cause compete confusion!

[Colin Lindsay]

3 hours ago, NonMember said:

Except on Saab 99 (and some Renaults), where the engine is installed backwards. ?

 

...and on Honda engined Rover 213s, where even the Haynes manual got it wrong and left me stuck at home for a number of days until an AA acquaintance sorted it for me.

[NonMember]

11 hours ago, Colin Lindsay said:

 even the Haynes manual got it wrong

Isn't that normal?

[willis]

Hi everybody, I thought I had my car was set up with number one piston at the front, but despite everything seeming to be set correctly, it still wouldn't start. Got someone out to look at it and after trying several different things, he changed plug leads so that number one was at back of engine. The car started first time and after a little more adjustment to timing and carbs it now runs perfectly. Don't understand how this came about or if it's right, but it sure felt good to hear and see it running again after such a long time. Does the distributor only locate one way because I tried to turn the shaft 180 degrees but it wouldn't drop into place properly?

Thanks, Rob

[Clive]

Number one is at the front. Somebody must have set the engine (or plug leads) up with number one cylinder at top of piston, but not compression  stroke. Easily done....

The distributor has an offset so only locates one way. But the drive gear can be put in at almost any angle.

(this webpage explains it fairly well,. Roundtail spit, but the principle is the same https://roundtailrestoration.com/2017/05/23/triumph-spitfire-engine-rebuild-20-auxiliaries/)

[Pete Lewis]

just to add if the dizzy is 180deg out it doesnt matter where the rota points so long as it points at the lead for no1 on firing stroke and the leads all then follow the firing order anticlockwise

you can fit the dizzy offset drive in incorrectly if there is enough slack its possible for the offset will drop in 180 out theres some tee shirts about for that.

if  you have a lucas dizzy you can remove the points cam and turn it  half a turn , not possible with the delco 

Pete

 

[willis]

Thanks chaps, as soon as I'd sent the message I had the same thoughts, but thanks anyway. It's good to have confirmation. On a different subject, there is a green wire and a green/brown wire in the engine bay which I think should be connected to the reverse light switch on the gearbox. Is this right?                                                                                                                                           Thanks again, Rob 

[NonMember]

8 hours ago, willis said:

On a different subject, there is a green wire and a green/brown wire in the engine bay which I think should be connected to the reverse light switch on the gearbox. Is this right?                    

That sounds right according to the WSM wiring diagram.