M30 head bolts oiling

[535ise]

I read in the Bently manual that the bolt heads need a light coat of oil but i think i read on here some where that the threads need a light coat of oil to ?

Should both sides of the washers be oiled aswell ?

Is that right or am i going nuts ?

Thanks

Andrew

[winfred]

i give em a light shot of spray lube (usually pb or kroil) just enough to wet them, make sure the holes are not full of coolent or oil as you can crack the block that way if you crank a bolt down on it (seen it)

[joshua43214]

Any bolt that has a high torque or critical torque needs to be lubed if its not precoated with graphite. You also need to lube the washer. Just lay all the bolts on a rag and give the washer a shot and run a shot down the threads with an oil pumper can.

If you really want to stress about it, dump them all in a pan of oil, then set them on a rag for a few minutes.

What is just as important is to remove all the oil from the hole, not only will excess oil cause the bolt to hydrolock causing faulty torque readings, it can break the engine block if its bad enough. Lay a rag over the hole and blow compressed air into it. If you don't have a compresser, soak it up with paper towels twisted into wicks.

[2fast]

That's a handy tip Joshua43214

[535ise]

Thanks a lot for your help

One more question that i've thought of is a thread tap the same thing as a thread chaser ?

I haven't got a head bolt to measure but i've got a M12x1.75 tap i can use to clean the head bolt holes out if it's OK to use ?

Thanks

Andrew

[winfred]

a chaser would be better, it's far less likely to damage the threads

Thanks a lot for your help

One more question that i've thought of is a thread tap the same thing as a thread chaser ?

I haven't got a head bolt to measure but i've got a M12x1.75 tap i can use to clean the head bolt holes out if it's OK to use ?

Thanks

Andrew

[joshua43214]

Chaser cleans threads, tap cuts threads, bottoming tap cuts threads to the bottom of a hole. Even I would be a bit hesitant to run a tap down a head bolt hole, but you may have trouble finding a chaser you can get down the hole since most of the ones I have seen have a hex drive rather than a square drive.

Cut a couple of grooves on one of the old head bolts to imitate a chaser and use that instead.

[535ise]

Thanks again for your help

I hope the weathers good this week end so i can do the HG !