Odd torque loss when driving near redline

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Stand-in
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My E21(s): 1977 320i US Manual
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Re: Odd torque loss when driving near redline

Post by Stand-in »

Was black occasionally, then it would be blueish, then more white, but mostly darker. I already tested for head gasket issues, that's only 3000 miles old if even at this point.
I went to start it today, it had the same bogging issue, I went and removed the spacer and it cleared right up, so my pressures were now to high. I think there was something propping the pressure regulator plunger open. Now it runs better, and as the fuel has reduced in afm I have encountered pinging, so I retarded the timing quite a bit. Now it smokes less and has more torque overall despite being retarded. I think the flame front is traveling faster/the spark plug is having an easier time jumping. It also seems more happy now, less weird noises to complain about.


Stand-in
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Joined: Tue Jan 09, 2024 2:46 am
My E21(s): 1977 320i US Manual
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Re: Odd torque loss when driving near redline

Post by Stand-in »

Ok it wasn't knock or pinging (entirely), it was my crank pully coming loose. Anyways I do think it was a bit over advanced.
Stand-in
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Re: Odd torque loss when driving near redline

Post by Stand-in »

My afm baffle plate was resting too high, it caused a stumble on throttle, hard starts, and a extreme sensitivity to fuel mixture changes. Dropped it by .5 mm and voila. Now to see if my mpgs improve.
So to summarize at this point, my throttle plate was off, the car was a hair too advanced, and the final trouble was a disintegrating pre wur screen.
With any luck when I go to start it up tomorrow it will just kick over instead of the usual way to rich shenanigans that I have to deal with in the first 15 seconds or so.
Also it smells much better!
In any case it seems I have a very worn out engine. I suppose I need to save up some scratch now and acquire a engine crane along with get to talking with the local machine shop for a potential overbore as my piston walls had some rust after sitting for 10 years, had a mechanic check it out and he said it would run just fine, but of course he presumed I would not take it to higher rpms I suppose. Oh well, for now Lucas film and some top end lubricant seem to be treating the car right.
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Jeroen
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Re: Odd torque loss when driving near redline

Post by Jeroen »

It usually ends up being a combination of factors indeed. Fingers crossed for a decent cold start tomorrow morning!
Regards/groeten, Jeroen
Stand-in
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Re: Odd torque loss when driving near redline

Post by Stand-in »

Yeah, I leaned it out some more and its running better. Still some rich run condition at start. The fifth injector just makes it hard running. I don't know what more I need to do to get it to go right, I will consult my repair manuals for ideas.
As for blue smoke I don't think I have piston issues, It seems to be more top end stuff, which means I can hold off longer on a full rebuild and save up for a stroker kit. Right now I think I have a valve stem seal issue along with some noisy valve stem issues.
My plan is to grab a very mild cam and do some port matching and smoothing at least on the exhaust side, perhaps I will stick some lightweight valve train components and stiffer springs. I don't know yet, I am both liking the prospect of more horsepower but I want to hold off so that when I do a fully built engine its got more of a WOW factor to it. Then again that's really going to be down to the turbo so I think I will just do some minor NA tweaks.
For now I'm going to see what some seal in a can can do for me as I have had good luck in the past.
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Jeroen
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Re: Odd torque loss when driving near redline

Post by Jeroen »

:thumbsup and valve stem seals are most likely the main cause for blowing blue smoke
Regards/groeten, Jeroen
Stand-in
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Re: Odd torque loss when driving near redline

Post by Stand-in »

Mechanic in a can fixed the smoking, and I dialed in the timing to Euro spec. The car runs really smooth now. Its a bit of a hard start though, and honestly I expect that most of the problem is the lack of vacuum advance as its an off idle stumble, but this goes away after 10 seconds or so of runing.
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Jeroen
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Re: Odd torque loss when driving near redline

Post by Jeroen »

Getting better by the day!
Regards/groeten, Jeroen
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