top dead center ?????

[lukieboy]

hi guys i have a really stupid question for ya...............how the **** do i find top dead center in a vp????

[HDT_aero]

the only way i know is to get an air compressor and a fitting to screw into the spark plug hole and let the pressure push the piston to the bottom (number 1 of course) then mark the harmonic balancer and turn it exactly 180 degrees you can then check its dtc buy firing up the compressor again and if it is a true tdc then the engine wont rotate and the piston will stay at the top.......

you have to let the compressor build up pressure in the tank first to do this otherwise one of the valves will allow to much pressure out and wont push the piston down and if all else fails the rocker cover comes off and you take no1's rockers off

im sure theres probably an easier way and som1 will laugh at this method of madness but hey thats the only sure way i know

[lukieboy]

i aint laughing mate and **** thats a bit of work lol
please let there be an easier way

[soop]

How close to TDC do you want to get?
Stick something through the spark plug hole and turn the motor over untill you feel the piston move back down. Once it starts to travel back down, turn it back the other way till you find the point just as its ready to travel back down.

Then you can use a timing light.

[Morton]

The easiest way I found to get TDC, is to get someone turning the motor over manually, while you stick a long thin piece of metal through the #1 sparkplug hole. You can feel the piston come up and judge it from there.

I hate finding TDC on a V6... it's hard to know whether it's true TDC or just at the top of the compression stroke so much easier on a V8 with the timing mark on the crank pulley

[tntracing]

As Morton said use a screw driver in the spark plug hole rotate the engine until the piston is at the top of it's stroke you'll see the screwdriver stop and start to move down,but be careful it doesn't wedge in there against the piston and head .TDC will be when both valves are closed which you will know by checking the rocker gear there will be a slight gap between the valve and the rocker,If you got it right when you spin the engine in the correct way after you think you got TDC the inlet valve will start to open.....Or you can just line up the harmonic balancer timing mark "0"

[Pub247]

can i ask why you need tdc?? is it a v6 or v8???

i always found easiest way to do it is take rocker cover off and check it the rockers method

[Morton]

Removing the rocker on the #1 side is a good idea, I never really thought of that

[lukieboy]

its a v6 and just want to make sure i have everything nice and tight (rockers recently cleaned along with push rods )

[Pub247]

just remember rockers have a torque setting of 36nm i think also theres no need to get tdc if all you did was remove rockers and pushrods

[Pub247]

I hate finding TDC on a V6... it's hard to know whether it's true TDC or just at the top of the compression stroke so much easier on a V8 with the timing mark on the crank pulley

Yep finding true tdc is very hard use a dial indicator if you want to find true TDC and even then its hard on a fully built motor especially if your trying to do it off a pushrod

[muttley383]

Try making a piston stop out of an old spark plug that has been gutted and tapped to take a bolt.
Install the piston stop in #1 cylinder, turn crank by hand in a cw direction until the engine stops and mark the crank pulley against a reference point on the engine.
Now turn the crank in a ccw direction until the engine stops and mark the crank pulley.
TDC will be exactly half way between the two marks on the pulley.
Note: do not attempt to start the engine with the piston stop in place for the obvious reasons, ie: damage to piston.
The above method is used to find TDC on an engine during the cam timing setup process when the timing cover is not yet installed.
Hope that helps and makes sense.

Just another note: you need to make sure you work out the TDC @ the firing point of #1 cylinder and not 180 degrees out.