No power at low rpm

[paw140]

Still making slow progress on my ‘69 S4… it is a federal car running Strombergs. Now the major issue is that it has very little power and is ‘boggy’ below 2000 rpms. Once the rpms hit 2500 or so, it has lots of power and seems to run fine. Here are a few observations and things I’ve tried.

- I removed the crossover tubes and the secondary butterflies.

- My spark plugs were black… I put in hotter ones and they are black once again. I’m assuming it’s from oil… see the next comment.

- I’m burning lots of oil. The engine was ‘rebuilt’ by the previous owner but I don’t think he knew what he was doing. The engine was mostly assembled when I got it. I’ve had previous issues with improper valve shimming that I’ve discussed in a previous thread, but that is now fixed. I get lots of oil smoke out of the exhaust, but I’m hoping the rings just haven’t bedded in yet. I’ve only driven a total of 7 miles. After running, when I remove the spark plugs, there is a small pool of oil on each piston. I’m worried this is the root cause of my issue (plug fouling from oil contamination at low rpm), but I’m not totally convinced yet.

- I set my timing at around 11 degrees. The timing seems ‘jumpy’. It does advance when I rev the engine, but it is not smooth. I’m wondering if my distributor needs rebuilt. Also, I’m suspicious of the cheap Harbor Freight timing light because it has a degrees advance knob that doesn’t seem to work accurately and makes me question the whole device. It is brand new.

I’m thinking to play around with the timing and see if that makes a difference. My biggest fear is that the piston / ring installation wasn’t done properly and I will need to do a rebuild to make it run right, but I really don’t believe this is the case. All suggestions are appreciated.

Thanks,

Paul

[rgh0]

Hi Paul. What ring bedding procedure have you used. If you have only done 7 miles the rings will not yet be sealing well so to early to tell if they have been done right.

Take the car out on a quite section of road and do repeated full throttle accelerations from around 2500 to 5000 rpm in third gear and then coast down to 2500 rpm and repeat . Do this for about an hour and about 30 to 40 times. I normally do it using a "running in" oil as these are formulated to help the process. A normal cheap mineral oil is Ok but dont use modern full synthetics as they can lubricate too well and the ring bedding in can be hindered

cheers
Rohan

Appropriate that my 8000 message is about engines

[h20hamelan]

Nice 8000th post Rohan, and I bet you’ve been waiting to proclaim bedding in procedure for a while as your new engine must be ready (or maybe you’ve fired it already)

Nice work, and thanks for your great contributions Sir or Dr or both Rohan