21 replies to this topic

[tiger99]

I think that some creep could occur after first tightening the bolt, so it is quite reasonable to leave if for a few minutes, then loosen slightly and re-torque.

But as to heat from the torquing process, the effect can be calculated. How many turns of the bolt are required between becoming initially tight and reaching the required torque? If someone can tell me that, when I get back here next I will have a go at doing the sums.

[bmcecosse]

The actual tightening of the bolt will create insignificant heat - yes - there is a possibilty of the flywheel creeping up the taper slightly so the tea idea will do no harm. A healthy whack with a lump hammer on the bolt head is not a bad idea before the final tightening. Fitting hot......hmm...not tried it but would be afraid of it never coming off again... Lapping with fine paste is definitely worth doing.

[ryan22_lgm]

i like the idea of the tea method cause we all love a good cuppa and it gets the job done properly!

[tiger99]

Please, people, do not fit a flywheel hot! It really will never, ever come off. I just hate to hear of disasters like that, it is so sad. Likewise, pulling the flywheel with the crankshaft at TDC instead of 3 o'clock. You may get it loose, but will you ever get it off, or back on?

[mini13]

Err... it will come off,

I do this on all my engines, and have done for several years, I heat the flywheel to 150 deg in an oven then fit it as quick as possible.

Think about it people, how hot does the flywheel get from a hard take off on the strip or from slipping it in traffic....

[dklawson]

The difference with preheating the flywheel to fit it... and the heat generated at a fast start... is that in the second scenario the crank is already in contact with the flywheel and the crank and flywheel will expand at the same time AND not much heat is able to quickly reach the flywheel/crank interface. What you are doing with preheating at installation is a shrink fit as I described earlier.

I am not disparaging what you are doing. As I said earlier, I'm sure the flywheels really stay on tight. However, like Tiger, I have to wonder how hard the flywheels are to remove!

[mini13]

seems to come of like a normal flywheel, I've never had trouble getting a flywheel of that hadnt friction welded/galled ( or whatever you call it) to the crank, I belive I'm preventing the welding by shrinking the flywheel on and using a higher torque, Ive certainly had no welding issues using htis method.