The 24 Hours of Lemons Forums → Lemons Tech → Running on Three Cylinders
Hello,
After many (MANY) mechanical issues this last weekend we decided to run our Miata for around 125 laps on three cylinders with the fuel injector disabled on the one bad cylinder.
I'm going to swap in another long block before the next race and was wondering if y'all think we ruined the old motor by running it so long and hard on three cylinders.
Thoughts?
I wouldn't think so. I would have the head and the block decked if you're going to try to reuse that motor though. Probably cheaper just to swap in an ecotech...
Why did you have to run on three cylinders? I heard that you guys had no compression on that cylinder. If so, you have to take it apart to fix that anyway, so do a complete inspection then. That being said, sometimes its cheaper to just buy a used engine and junk the old one.
It will be fine
The new head and head gasket lasted four or five laps before compression went away on #2. This was at the end of Saturday and pulling the head again was deemed to be too much. Thus we finished on three cylinders. The copious rain on Sunday also helped us not be too terribly off the pace.
My more mechanically-inclined brother-in-law also thinks the block might be salvageable and will be checking on it soon. We pulled the three-banger engine last night and will hopefully know the broad strokes by this weekend.
Around here Miata motors seem to go at a premium. Heck, I got my current spare by buying a wrecked Miata for less than long block goes for on the open market ($600-$1,200). I blame people that race Miatas.
Ha, I think an Ecotech swap would be cool at some point. A lot of benefits there - reliable power, plentiful cheap motors, it's a proven solution. We'll see.
If you had compression issues, you're addressing the engine anyway. Pull it apart, deck the block and head, put a new gasket in. While it's open check the bearings, cylinder walls, piston, rings, etc. If it's good, run it.
The new head and head gasket lasted four or five laps before compression went away on #2. This was at the end of Saturday and pulling the head again was deemed to be too much. Thus we finished on three cylinders. The copious rain on Sunday also helped us not be too terribly off the pace.
My more mechanically-inclined brother-in-law also thinks the block might be salvageable and will be checking on it soon. We pulled the three-banger engine last night and will hopefully know the broad strokes by this weekend.
Around here Miata motors seem to go at a premium. Heck, I got my current spare by buying a wrecked Miata for less than long block goes for on the open market ($600-$1,200). I blame people that race Miatas.
Ha, I think an Ecotech swap would be cool at some point. A lot of benefits there - reliable power, plentiful cheap motors, it's a proven solution. We'll see.
Miata motors are also Escort GT motors, Kia Sephia motors, Suzuki Esteem motors, Mazda Protege motors and a few more I forgot. If you currently have a VVT motor...stop having that so that you can use all of the above. I am not kidding, VVT is is not enough help for the extreme premium for the motor in the Miata world.
The new head and head gasket lasted four or five laps before compression went away on #2.
Yea that's telling you something. Get the Head and Block decked.
FWIW, I did my best to clean off the gasket surface of the block before the new head went on but there was some tenacious stuff I couldn't get off on the drivers side front of #2 where we lost compression. If I had to guess, that's where you'll find a blown head gasket.
We also dropped some oil into the cylinder and it did not raise compression at all.
The new head and head gasket lasted four or five laps before compression went away on #2. This was at the end of Saturday and pulling the head again was deemed to be too much. Thus we finished on three cylinders. The copious rain on Sunday also helped us not be too terribly off the pace.
My more mechanically-inclined brother-in-law also thinks the block might be salvageable and will be checking on it soon. We pulled the three-banger engine last night and will hopefully know the broad strokes by this weekend.
Around here Miata motors seem to go at a premium. Heck, I got my current spare by buying a wrecked Miata for less than long block goes for on the open market ($600-$1,200). I blame people that race Miatas.
Ha, I think an Ecotech swap would be cool at some point. A lot of benefits there - reliable power, plentiful cheap motors, it's a proven solution. We'll see.
Time for some forced induction Benz power 
I bought an SLK230 supercharged motor from LKQ for $500 last month. With a 1 year warranty, it's running great without so much as new spark plugs. Probably not a simple bolt-in, but they sound like tractors and pull like an SBC... 200 lb ft torque over a 4000 rpm range..
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