Starting up after head-gasket change

[Anigmalistic]

Hi guys,

The head gasket on my wife's 1998 1.9 Z3 blew between the water jacket and No. 1 cylinder last month, and my next door neighbour who is a rather talented young mechanic has been replacing it for me.

He's using the Haynes manual, which is actually the 3 series manual but includes the Z3 and has the engine fully rebuilt and ready to go, however he's come across an oddity:

The Haynes manual tells him that the first time starting the engine back up he should immediately hold it at 3500rpm for 20 seconds to lubricate the timing gear, however this goes against all his experience, instinct and basic training as a mechanic... everyone knows you don't run an engine hard straight from cold, especially after major work.

So I was wondering if any of you could advise us how to proceed? Obviously we don't want the timing gear not to be lubricated, but equally we don't want the engine damaged by revving it from cold. Have any of you had experience with this, or, I suppose more importantly, have any of you experienced an engine which has been damaged or had problems caused by either carrying out this step or not?

Thanks in advance,
Pete.

 

[zedonist]

If you are not comfortable, you could always ensure that you lube the timing set up before starting the engine and use run in oil, but in all reality it is not readline revs and only for twenty seconds to ensure the oil has got round the engine. I would suggest that if it is in the Haynes manual you would have grounds for re-course if it did go wrong. my own personal opinion would be to disconnect the coil and just crank the engine to get oil around the engine first, and then fire it up, and i don't think then going to 3500 rpm will do any harm.

 

[Aceman]

Agree if you crank the engine first without spark until the oil pressure light goes out and then some more to be on the safe side you should be OK. It shouldn't take much to get the oil up into the head but lubing the cam lobes before you put the cam cover on should be enough for the few seconds before oil is delivered to the head.

 

[t-tony]

I would lube the cam lobes and related parts with Wynns oil treatment, STP or similar as they are very viscous and will stay on the coated areas and will suppy enough lubrication for initial starting.

 

[Anigmalistic]

Hi guys, thanks for the replies.

He took your advice, made sure there was plenty of oil round the top of the engine, cranked it without starting and then went for the 3500 rpm start. Seems to run perfectly!!

So... clutch is next, then get the hood sorted, then the mirrors, then the upholstery... the list goes on but it's getting there!!

Thanks again!

 

[GazHyde]

So... clutch is next, then get the hood sorted, then the mirrors, then the upholstery... the list goes on but it's getting there!!

Keep chipping away at the list and it will soon be done!

 

[zedonist]

Marvelous, good to hear it was successful, it will become a love affair.......