'83 911SC low or weak engine power
 

Hi folks, newbie here. I have been reading this forum for a month now, getting lots of helpful tips from all of you while I prepare my new (to me) Porsche for the road. Bought it in Phoenix in May, trailered it home to Penticton, BC, Canada.

I have sorted out many of the engine running issues, new plugs and wires (with steel braids), new cap, new intake gaskets, rebuilt (sealed) air box, new O2 relay, valves adjusted, new synthetic oil and filter, and valve cover gaskets.

My problem is power, or lack of. It is like I am launching the car in 2nd gear, and if I am on a bit of an uphill, it's all I can do to get her rolling. I can't say this is a new problem, or getting worse because I just haven't had that much road time since getting the car licensed. But if I had to swear on it, the issue is worse now then when I first put on the road last week. However, once launched and rolling sufficiently, she seems to have great power. BTW, is it typical to travel at 50 mph turning 3000 on the tach in first gear? And yes, I checked that I am in first, not third, gear.

I have not changed the coil, or the CDI box. Been reading about testing these, but not sure if weak spark is the (only) possible cause.

You suggestions would be greatly appreciated.
Glenn

Is your clutch slipping? Is the clutch/basket/throw out in good order? Is the clutch properly adjusted for full engagement (clutch cable)?
I'd also do a search on oils for flat tappet air cooled 911's if you are using a full synthetic....what type?

This is not right.

Let me find you a graph.

I think you may be in third.

http://forums.pelicanparts.com/porsche-911-technical-forum/244939-custom-gearbox-recommendations.html

Shifter out of alignment perhaps... that's not 1st gear. 50mph in 1st would probably be around 11,000 rpm as a rough estimation.

I've experienced this. Bob is right. The car is in third gear. For me, it was a mis-alignment of the coupling in the tunnel under the inspection hatch in the back. Simple fix - just loosen and roll it and try again.

In the link I posted, go to Bill Verburg's post number six. First graph "stock" 915 and put a straight edge on the third gear line. Walk it down to 3,000 RPM's and you are at 50MPH.

Yes - loosen and roll to the left if I am thinking straight. There are procedure instructions for fine tuning. Find them and execute.

Here is some data to chew on. I bet you are in good shape after this. Have a friend help you.

http://www.pelicanparts.com/techarticles/911_shifting_improvements/911_shifting_improvements.htm

he is definitely in the wrong gear .. the good news is it is a very simple fix to reallign the gear shifter if that is all it is ..

Nah - around 7,000 (based on the Verberg graph) but still the same order of magnitude - a whole lotta RPMs to do 50mph

So does the car only seem to have 3 gears plus reverse?

there's no way the sc can hit 50mph in first gear. maybe half that.

This is the real question.

It can come close - but clearly not the argument in this thread.

Don't make me prove it cause I got some friends. namely Ordell Robbie, that will take you for a short ride in the trunk of his car.

Beaumont Livingston ring a bell?

http://forums.pelicanparts.com/uploa...1373407565.jpg

Looks like 7,000 will get you 40 per my 81 owners manual.

http://forums.pelicanparts.com/uploa...1373408681.jpg

https://www.facebook.com/pages/Dons-Werkshop/318896078223764

you might want to chat with Don if you need help. Great person.

I bet your rear shift coupler has bad bushings and there breaking!

Thanks for the suggestions everyone. Clutch is good, cable adjusted correctly, but maybe linkage is out. I did have the engine out and for that I separated the coupling under the access in the back seats. Was sure I had it back together correctly, but ??? The weird thing is that when I shift from 1st to 2nd the engine responds as expected - rpms drop, throttle has more room for acceleration. Also, because I wondered about this issue, I moved the shifter from 1st to 3rd to 5th to satisfy myself that there were at least the three detents. I will read and reread the instructions for correct alignment, then attempt to get it right. It'll be great if this is the problem.

Glenn911....so can you just shift in 3 gears (3-4-5th)....that'll answer the present suggested solution?
If you can only get 3 gears an easy fix....if you can use 5 gears you have another issue.

50 MPH in 3rd gear on mine is in the 3000 RPM neighborhood.
Check your shift coupler bushings.

Give me a call ,I can walk you though it

it was a mis-alignment of the coupling in the tunnel under the inspection hatch in the backhttp://www.camj.info/7b.jpg

Did you take it out and have a look?
Don't just just it with out looking it.
If you'er bushing is going out this is what it's going to do!