4 replies to this topic

[tb205gti]

I'm about to change the cam in my 1977 998 A engine - but I'm unsure what oil pump it has been fitted with from the factory.

 

I have good and healthy oil pressure - so I'd rather not start changing the oil pump.

 

Anybody know what a 1977 998 was born with?

[Swift_General]

Likely to be pin drive. Whilst you have the engine apart it really is worth changing the pump though as a matter of routine as they pick up unfiltered oil from the gearbox.

[tb205gti]

I was hoping to be able to change it without taking the engine out. :/

 

The head has been fitted with double springs, i have new cam followers, cam lube tec. I was hoping that I could slide it out the inner arch - and slide a new one in..

[Swift_General]

It can be done by cutting the radiator grille in the inner arch but is a bit of a pain to do having done it once in the past. Plus if you're going to the trouble of changing the cam then you'll need to confirm the cam timing and adjust as necessary which will be harder with the engine in.

[MRA]

This is potentially going to end in tears for a whole load of issues...

 

1) it will be impossible to remove and refit a camshaft without some damage to the cam bearings.

2) The new cam, if it allows for higher revs this will cause reliability issues, such as premature ring failure due to conrods and pistons stretching further than they previously stretched to and the step in the bore (due to wear) damaging the top ring.

3) any dislodged dirt that is then carried into the bearings.

4) No way of checking if the new cam runs loose or tight in the bearings, (measuring the bearings on the camshaft is only part of the job.

 

However if you are lucky you will get it all just right and end up with a good reliable engine, hopefully you are lucky.