1978 318 Preventive maintenance

[SFerrari]

Hello,

As I just bought my 1978 318 BMW, I have the desire to do preventive maintenance on the engine !
Actually the car and engine run perfectly, no noise, no strange sound... nothing particular to notice, BUT the engine has over 40 years old and (only) 134.000kms.
For your information, everything is stock and never been changed on the car (on the engine I mean). The car has always been well treated and maintenaned in the past (oil change and so on, if you wonder)...

I want to take the engine out of the car, and clean/renew/change (for my pleasure) all what needs to be. But if I don't have to, why to bother, so :

At this stage, I'm wondering if I have/need to go that far in the preventive maintenance and change : head gasket and timing chain/tensioner/guides ?
Or do I could leave it like that and only consider checking/changing the tensioner and guides if needed ?? I know that I will know the real condition only once I have checked out the real condition, but in the usual good practice, do the original head gasket and timing chain as to be changed after 40 years as I take the engine out anyway ??

Thanks in advance for your advice and feedback

[Wilmo]

For an M10… don’t really bother nothing really can break leaving you with a stop. The breakdowns I’ve had were a broken alternator and a bolt that flew out of the exhaust manifold spraying oil on the exhaust manifold. Btw, that was with a similar engine as you have.

Nearly all other things gently knock on the door ‘please sir, it is time to replace us’. There are the chain guides, but that will rattle first. And the valve stem seals, which will leave a nice trail of smoke.

Do not take the head of if it is not really needed. Valve stem seals… hmm. You might need to take the head of for that since the rocker shafts come out at the back i believe. Chain guide you can do with the engine in the car.

When it is for your pleasure… consider to get a second engine and do it in rest and peace on that one and change afterwards.

[SFerrari]

Thanks for your reply, very appreciated

So, really, I can leave a 43 years old head-gasket, valve stem seals, and timing chain/tensioners/guides ?

I'm a bit scared in one hand to leave it like that (as the car was not much used in past 8 years) and in the other hand I take the engine out so why not doing it ? The only thing that makes me asking here and not doing it straight away, is that I have never done a timing chain ever and don't know if it is a doable task (I mean if there are not too many tricks here and ther to be aware of...

Also I try to gather some feedback here about the opportunity of doing it or not... I understand that you wouldn't bother, ok

Thanks !

[Wilmo]

If the engine is going out… that’s maybe a bit different. For the valve stem seals you have to disassemble the whole head. Timing chain is really no problem if you follow the marks etc, you have to do your best in screwing it up.

But really, I would wait taking it out until problems start to occur.

If you take the engine out, renew the clutch, crankshaft seal, bearing and clutch cilinder. Change that thing every three years anyways.

If there’s a leak around the oil pan, change the seal. You can’t do it when the engine is in the car. While in there, take a look at the internals. Based on that maybe do some shimming on the oil pump to tension the chain. But most of it… when it’s working, don’t touch it :p

Change the bushings on the alternator to PU. The rubber gets soft and then the alternator is pulled to one side.

[SFerrari]

Thanks very much for all the information