47 replies to this topic

[o0OWILKSO0o]

So I'm getting all my bits together to fit my Nodiz dizzyless ignition system, but when I fit the trigger wheel it needs to be at TDC.

Is there a deffinitive guide to do this? Or is it in the haynes?

[Cooperman]

There is an oval plate on the clutch cover. Remove this and there should be a TDC line in the flywheel which lines up with a 'nib' on the clutch cover.
I can't remember whether that also exists on Verto flywheels as I always mark a TDC mark on the front pulley and timing cover or highlight the existing marking points on front pulley & timing cover with a bit of yellow paint.

[o0OWILKSO0o]

I read something about a screwdriver down the spark plug hole and it rises. Am i chatting cod ****?

[Noah]

You could also find it with a DTI guage, mounted on the cylinder head and inserted into a bore, find the tipping point by carefully adjusting the crank with a socket.

Or you can go really old school and do it with a a screw driver, though not very accurate.

[o0OWILKSO0o]

Seems very technical, can't I just hit it with a hammer or grind something off? I think I will have to get someone engine minded to help me

[Noah]

Seems very technical, can't I just hit it with a hammer or grind something off? I think I will have to get someone engine minded to help me

A DTI gauge really isn't a confusing item, I'd say its one of the most vital tools when engine building.

Watch the JanSpeed D.I.Y Mini Video on youtube, all will be explained in there, it's 4 parts. I will say for certain you'll have to watch it about 5 times. LOL.

[Cooperman]

For what you are doing you do need it to be accurate +/- 1 degree.
A screwdriver down a plug hole will not be accurate enough. Do you have no markings on the front pulley with a small bracket on the timing cover?
The only other way to get it spot on is to take the head off and use a DTI on a piston crown, then make up a small bracket adjacent to the front pulley and mark TDC in light coloured paint.

[Noah]

Part 4, 3:22. Evidence of finding TDC with a DTI.

[Artful Dodger]

To find the TDC

Remove plug
Get screwdriver
Put screwdriver in home until you feel piston
Rotate crank until the screwdriver it at the top of its travel

This is TDC. You will need firing on no.1 cylinder TDC though. When the engine is as general TDC it's either on the firing stroke or the exhaust / intake stroke. For the engine to be on firin stroke both valves should be shut. This means the rockers will have no weight on them and they will be able to rock slightly

For firing on no1 cylinder and TDC, screwdriver at the top of travel, both rockers able to be rocked slightly



Hope this helps on cowboy mechanics! ;)

[Artful Dodger]

For what you are doing you do need it to be accurate +/- 1 degree.
A screwdriver down a plug hole will not be accurate enough. Do you have no markings on the front pulley with a small bracket on the timing cover?
The only other way to get it spot on is to take the head off and use a DTI on a piston crown, then make up a small bracket adjacent to the front pulley and mark TDC in light coloured paint.

On the Nodiz setup you have a big margin for adjustment, so it doesn't have to be absolutely bang ln

[o0OWILKSO0o]

Gleaming cheers guys. May be back in touch when i start next week.

[Cooperman]

Yes, I guess you just want a basic timing setting for start-up then tune on a rolling road to programme it.
You do need an accurate TDC for timing in a cam, but then the head can be off so that you get it absolutely exact. I do like a reference point, but it's not vital.

[Artful Dodger]

Yeah I wouldn't use that to time in a cam;).

I have heard of a DTi guage going down the spark plug hole though, means cam changes can be much faster

[MRA]

I would not use a screwdriver down the bore, for risk of damaging a piston and or dropping swarf or other horrible things off the end of the screwdriver... yes of course I would have cleaned it anyway, however always best to err on the side of caution.

If its verto flywheel you will NOT be able to use the clutch cover and the "nib" as there isn't one fitted.

There are extra long DTI's I have one that is about 10" long, although these can be used on engines with the spark plugs above the centre of the piston, its not a good idea to use them on a Mini or similar as you will break it, and won't get an accurate measurement, you will be measuring piston position but won't be able to take into consideration piston rock.

You have yo measure above the gudgeon pin centre line.

[Artful Dodger]

Nope.

How old are you?


(just taking a leaf out of DILLIGAFs book ;))