Finding TDC.

[The_blue]

Is that little line on the outer edge of the dizzy TDC on number 1? (CU engine)


Would you say the cylinder number 1 is not at TDC with the rota arm there?

[ghost123uk]

Not sure about that dissy position but this is how I do it if I am not sure.

Take all the plugs out.
Stick your thumb firmly over number 1 cylinder.
Get a friend to turn the engine over with a spanner (not the starter motor )
Stop when you can feel compression building up against your thumb.
Then get a large "Tie Wrap" or similar plastic bendy thing.
Carefully insert it into the plug hole until it touches the top of the piston.
Then gently turn the engine over (slightly back and forth if need be) till you get to the position where the Tie Wrap is as far out as it can go. = TDC on the firing stroke (works for all 4 cylinders of course too)

Don't insert anything into the plug hole that might jam up and damage threads, pistons, valves etc - Like don't use a screwdriver, or anything that might break off, like a pencil or Biro !!

~~~~~~~~~~~~~~~~~~~

p.s. = I did it on an old BSA 500cc singly motorbike once, with a pencil, and it did break off.
I though flip it, and fired it up anyway. It ran, coughed a few times (wood stuck in the valve seats) - chucked a few bits of mangled wood chips out of the exhaust, but was non the worse !!

[The_blue]

Ah, of course! thanks!

I'd got TDC on one worked out. (timing marks) but couldn't get the others worked out. haynes says just turn till dizzy is 90 degrees off number 1!

done 1 set of tappets anyway. was 2 and 3/4 turns in!

[ghost123uk]

Ah, of course! thanks!

I'd got TDC on one worked out. (timing marks) but couldn't get the others worked out. haynes says just turn till dizzy is 90 degrees off number 1!

done 1 set of tappets anyway. was 2 and 3/4 turns in!

Does you CU motor have solid tappets or hydraulic ones (very different to set up, as I am sure you know !)

I am no expert on Aircooled engines (in T3's anyway, though I just successfully re-built one in a bay for a friend

[The_blue]

Hydros. I'd leave them alone but i noticed someone had been at them when i did the pushrod seals.

I've got a tappet noice from number 2 that's not going with driving. I'm hoping it's just the last owners poor setup.

[toomanytoys]

1/2 (half) turn from just touching...

[Red Westie]

As a side note*: never scrape the crud off the rotor tip or distributor segments as this increases the air gap and voltage needed to jump said gap. The crud offers no resistance so don't be confused by normal thoughts of dirt equals resistance as in a normal connection (this is not a connection after all) the reality is scraping away to clean brass equals larger air gap which takes higher KV to jump so reduces the available power to the plugs.

Martin

[The_blue]

Oi! You trying so say my rota is cruddy?





Does the scortching just on one side look normal?

[The_blue]

Ok, all sorted.

I quickly realised the rip-tie wasn't going to be easy when I remember the engine was flat and the plug came in on the side. The piston trapped the rip-tie on its way up to compress

So...

I did 1 and 3 using the timing mark on the cooling fan. 2 and 4 I did by shining a torch down the plug hole and waiting to see the piston come up.

Most tappets were 2 1/2 to 4 turns in with one not touching. That one just happened to be the bank that was rattling.

Engine feels more responsive, but then again don't they always after you put them back together... wishful thinking maybe?

[ghost123uk]

Glad you got it sorted

It almost certainly will be more responsive (and be better on fuel too) now the valves are opening the amount VW intended them to

btw - not sure why your rip-tie got trapped - I have used this method on flat 4s with little bother - in fact just did one last weekend - but at least all is well that ends well

.