Can’t rotate the engine manually

[bose213]

Hello,

I have a problem when trying to turn the engine manually using a wrench on the cooling fan. The belt that connects the fan to the engine keeps slipping, even though it is properly tightened. Could this be related to the timing chain tension?

If it helps, my car has a Sportomatic transmission.
Porsche 911sc 1979 3.0L.

Thanks.

[walt]

You need to press on the belt to increase tension. Just one finger on one side will usually do it.

[2svnhvn]

Also you can rotate it by using a wrench directly on the crank pulley

[OldSpool87]

Press belt at midway point between pullies

[tobluforu]

Put a wrench on the crank bolt, it's a tight fit, can you rotate motor.

[A930Rocket]

Do what I did. Drill a hole to reach the crank shaft bolt!

[Bill Douglas]

A ring wrench fits down the gap to the nut on the end of the crankshaft.

I had a crashed donor car in a shed for 8 years and every month or so I'd rotate the engine 1/4 of a turn using this method.

[Alan L]

You can tension the RHS of the belt and that should work - finger tight as others say. But you can't hold it against that on the LHS.
Taking the plugs out will help. Even most of them if some put you off.
Yes Bill - I know that car well - or bits of it.
Alan

[garment]

Wut

Originally Posted by A930Rocket

Do what I did. Drill a hole to reach the crank shaft bolt!

[David Inc.]

Originally Posted by A930Rocket

Do what I did. Drill a hole to reach the crank shaft bolt!

Too early for April 1st!

[pmax]

^^^ Manual starter

Originally Posted by bose213

Hello,

I have a problem when trying to turn the engine manually using a wrench on the cooling fan. The belt that connects the fan to the engine keeps slipping, even though it is properly tightened. Could this be related to the timing chain tension?

If it helps, my car has a Sportomatic transmission.
Porsche 911sc 1979 3.0L.

Thanks.

Could be related to this ...
Knocking sound at low rpm (video attached)

[A930Rocket]

I forget why I drilled a hole in the license plate and bumper to access the crankshaft bolt, but I did it for some reason

[smadsen]

I'm told never turn the motor backward. Can't remember why. Timing chains I think & the tension thereof.

[dictoresno]

Originally Posted by smadsen

I'm told never turn the motor backward. Can't remember why. Timing chains I think & the tension thereof.

yea you will throw off the tension on the timing chain and possibly skip teeth, throwing off the timing.