E30 power loss
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Was the head decked/pressure tested?
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its a pretty good rule of thumb that if you didn't have a problem, then you did some work, then you suddenly had a new problem, its something you changed.
Dan
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I think I determined my problem; spark plugs.
Upon further investigation, I found that 5 of 6 of the spark plugs had not fully tightened when I installed them. I stopped by a parts store to pick up a different set in the event that the threads on these were not quite right, and found while looking at the picture of a different set that the small silver ring that threads onto the plug was on with the flat side facing the head, which was reverse of the way I had put mine on. I pulled all the plugs, reversed the direction of the silver rings and put them all back in; all tightened the way they should. In all of my years of changing spark plugs, I never knew that the direction these things were put on the plug made any difference. In fact, I'm not altogether certain that the plugs I use in my 66 Dodge even have these rings on them.
I think what was happening is that I was losing compression at the spark plugs due to their not tightening enough to keep all pressure in the combustion chamber where it belonged. The car accelerates much better now. I may still be losing a bit of power due to the fact that my muffler is about shot, but at least the car runs more normally.
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Flat spot on the washer???
Autolites are nobodys friend
Autolites weren't my first choice, but I had to have something and that was what they had in stock. I'm looking for different plugs. Ideally I'd like either Bosch or NGK.
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Ngk plugs are where it's at.
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I had good luck with my Bosch plugs but would like to try NGK. Is there a particular version of them you recommend?
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I had good luck with my Bosch plugs but would like to try NGK. Is there a particular version of them you recommend?
NGK ZGR5A, gapped to .032" is my suggestion for a stock M20
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I use the v power usually. The price is good, my e36 had the fancy 4 ground ultra plugs in it, I replaced them with ngk plugs which are OE and it gained 2 nog and ran noticeably better. I am not a fan of the iridium and other fancy metal plugs, none conduct as well as copper. The special metal ones are designed to last a long time, not provide better performance.
Sent from my 831C using Tapatalk
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This is true^^
My van has a label in the engine bay explicitly calling out the use of ONLY a particular multi-prong iridium plug. After replacing them (with basic silver/copper single prong plugs) I can appreciate their consideration for not having to access the rear 3 cylinders any more frequently than necessary.
Although, in a performance application, you could argue that the smaller diameter of the iridium electrode provides additional exposure to the mixture for flamefront propagation.
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NGK ZGR5A, gapped to .032" is my suggestion for a stock M20
I'll take a look for them. I'm sure I'll have to order them from somewhere as nobody around where I live seems to stock plugs for an M2O beyond either autolite or Motorcraft.
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