How to rotate your engine - tricks & tips?

[Dave Kay]

Or maybe my question should be; how do I accurately get my engine to #1 TDC on the timing mark?

OR; How do I incrementally rotate the engine?

To explain; I have an '86 GMC truck w/350 and the engine is in vehicle. I want to adjust the valve lash - cold - as per the Helm's book procedure. But trying to get this thing to #1 TDC is like catching a greased pig in a mudhole... using a remote switch and cranking the starter get's me close but never on the money. Then, I try to turn it by hand at the flexplate with all the plugs removed and can't get enough leverage... is this a fairly tight motor or should I be able to turn it by hand or what?

By the way, I am aware of the #1 TDC and #6 TDC correlation, so no problem there.

Online I found a flywheel/flexplate tool that looks like it may be the solution and Summit also sells a crankshaft turning tool that mounts on the t-dampener but that looks like there might be a clearance problem w/engine in vehicle. Heck-- I'd be willing to shell-out for a tool if needed but am wondering what others use to make this task simple? Painless? Accurate?

[Captkaos]

It doesn't have to be perfectly on TDC to adjust them.  If it is close you can adjust them.  Are you using the method where you adjust half the rockers one way then rotate it and do the rest?

I generally do like it is detailed here:
http://73-87.com/7387garage/drivetrain/valvlash.htm

[Dave Kay]

Thanks Capt-K, and I did see your link before but am not attempting the 90 degree method because I can only turn the motor by starter for now and that would be near impossible to do a perfect 90...

The Helms book gives a procedure where you only rotate once to #1 TDC for a certain set of intakes and exhausts and then you rotate again to the number 6 TDC and hit the rest, done deal. Seems simple enough but can't figure out exactly HOW you're supposed to rotate the engine to line up the timing marker with accuracy... keeping in mind that the engine is in the vehicle and not on an engine stand.

[werewolfx13]

I had some success using the crankshaft bolt on the balancer when I was setting the timing on the truck I gave my dad..the trans was out of it though, not sure whether or not that would make it impossible..

[77c15]

Take off any belts going to the crank pulley and turn it by hand. Should be fairly easy. Overtightening the middle crank bolt can break the bolt or cause a premature balancer failure.

[123 pugsy]

You can use the bolt on the damper as the engine will spin before it gets to the torque req'd to break the bolt. I do it with the plugs in with no problem.

[Captkaos]

Thanks Capt-K, and I did see your link before but am not attempting the 90 degree method because I can only turn the motor by starter for now and that would be near impossible to do a perfect 90...

You don't have to be at a "perfect" 90.  Once both valves are closed, they are closed for the full rotation.  having it go 93 degrees or 87 degrees isn't going to matter much on valve lash.  Same goes with the 180 technique, you only have to be close.  Just bump it over with the remote.  Doing it the 180 way would be easier since you only have to have it on TDC an BDC for the crank.  Like I said it doesn't have to be perfect.

[VileZambonie]

Use a 5/8 socket on the crank bolt. If your engine won't turn you have other issues.