Post Rebuild Oil

[1972_911T]

I finally finished my 3.2 rebuild tonight and fired her up for the first time. Firstly id like to thank everyone on this forum who as offered me advice throughout my rebuild and of cause Wayne's book for the step by step guide to rebuilding these engines. I will post pics of my newly finished engine tmrw when I get my camera out. I ran the engine tonight for about ten minutes at alternating speeds and intend to take it out for a drive tmrw to run the rings in properly for about 30 miles or so. Currently I have chepo ultra low quality oil in that I intend to change after this first drive tmw. What I want to know is can I then go straight to synthetic oil that I intend to use at every oil change for the car or am I best to stick to a mineral based oil untill its got a few more miles on it and when is the next time I should change the oil after this first change?

Thanks Steve

[afterburn 549]

By cheap I hope you mean non detergent....as far as syn oil goes its a religious thing...seems to ask for leaks in the air cooled eng. Also when you do all the home work there is not a lot of diff except price.....I know some will take exception to this but I have done a lot of research (reading)as I do not have a oil lab so I have to go with the confluence of things.

[cnavarro]

I would use a non-synthetic oil until you're put at least 1,000 miles on the engine. Preferably, 3-5k if you can stand to wait. Then you can switch to your choice of synthetic. I'm not sure if it's at all necessary to actually use a non detergent for break in any more, but if I were you I would at least add an anti-suffing additive. Anything with high levels of ZDDP would suffice. Although it's not very potent, the red STP 4-cyl treatment will do in a pinch- just make sure it's the one that has the viscosity of oil, not molasses.

[1972_911T]

The oil is detergent free but not by choice as I didnt realise it was an issue, whats the significance of detergants in the oil on a rebuild?

Steve

[afterburn 549]

The big deal is seat the rings insurance....at 1st I thought this was all old wives tales, but after much research that's the correct ans non detergent oil. I must admit I did like you (wish I had not) but all turned out ok...........make sure you follow "proper break in procedure esp. if you have a new cam....also to seat the rings.

[cgarr]

Yep, a good Straight Mineral Oil like Aeroshell 80 would be a good choice for break in

[cnavarro]

My thoughts exactly. I actually have some Exxon non-dispersant Av break in oil on the shelf. I had purchased it here: http://www.eliteetc.com/exoil.html

I still think it's a good idea to add some ZDDP at break-in.

[1972_911T]

So how does detergent in the oil affect ring seating I have searched all day on google and found opinions both ways but carnt find no explantion? Also how long should I use non detergent oil for?

Heres a pic of my newly finished engine



Steve

[cgarr]

We use the straight mineral in our aircraft for break in which is about first 50 hours or until oil consumption stops, don’t know how this applies to Porsche engines since they run at a lot higher RPM I think the big thing is to keep the power up over 60% to avoid glazing of the cylinders during this break in period

[cstreit]

yeah craig, but if you make a mistake in an aircraft motor, there's no one around to complain so how do you REALLY know it works?

I use a straight 30 weight non detergent oil, non-syntheic to break in our motors.

[1972_911T]

Right I have now done about 50 miles with my new engine all seems well no smoke and brilliant throttle responce. I think its about time I changed the oil. Should I keep with the non-detergent at this point? and if so how long for?

Steve

[afterburn 549]

"if" you have done progressive engine loading its time