New math formula
06-08-2007, 08:18 AM
#24
I checked my head the other day and it looks like my engine was the rings as well, not a burnt valve as originally thought.
On a side note to Hustler, I think the rings on my car and Scott's did not "go" b/c the tune, but from time, wear, and pressure. I'm not sure about Scott's engine, but mine already had 100K+ miles on it. Add boost to 12-15psi over longer periods of time and they will wear much faster. In my case, I was mistakenly running 15-18psi which really got to the rings.
FWIW, there was an old post from Jeremy at FM where he said that the reason FM recommends running no more than 12psi on stock engines was that in their experience the rings would routinely start failing on a stock block running higher than that for longer periods of time, the key thing here being running high boost over longer periods of time. Of course I read this after blowing my engine. Link to thread with comment by Jeremy: http://forum.miata.net/vb/showthread.php?t=179111
Scott, I think that other 1.6 near me is still available for $200 (the guy just wants to get rid of it so I figure you could probably get it for like $150), BUT it is a shortnose crank. I did have a long talk with the owner who had the complete history of the engine and said the front crank bolt has never been touched. Just a thought, if you wanted to throw that in to hold you over until a built engine.
On a side note to Hustler, I think the rings on my car and Scott's did not "go" b/c the tune, but from time, wear, and pressure. I'm not sure about Scott's engine, but mine already had 100K+ miles on it. Add boost to 12-15psi over longer periods of time and they will wear much faster. In my case, I was mistakenly running 15-18psi which really got to the rings.
FWIW, there was an old post from Jeremy at FM where he said that the reason FM recommends running no more than 12psi on stock engines was that in their experience the rings would routinely start failing on a stock block running higher than that for longer periods of time, the key thing here being running high boost over longer periods of time. Of course I read this after blowing my engine. Link to thread with comment by Jeremy: http://forum.miata.net/vb/showthread.php?t=179111
Scott, I think that other 1.6 near me is still available for $200 (the guy just wants to get rid of it so I figure you could probably get it for like $150), BUT it is a shortnose crank. I did have a long talk with the owner who had the complete history of the engine and said the front crank bolt has never been touched. Just a thought, if you wanted to throw that in to hold you over until a built engine.
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and some dont :(
06-09-2007, 04:36 AM
#27
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i have a 91 short block (no oil pan or crank but pistons and rods n shiz) you can have it for 25+shipping. downside shipping might be a bit more from 97219 to where you are. Dont know much aboot it got it to do a build and then was like meh and parting it out. If you need the oil pan pretty sure i have that laying around too. Was going to use it if i ever go back to NA that way i dont have a hole in the Oil Pan.
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06-11-2007, 05:27 PM
#28
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I found a smallblock without pan for $100, probably going to pick it up and rebuild it. One of those $200 rebuild kit deals. Throw my head on it and call it a day.
My problem was my engine was a JDM import with history unknown. With that said, I've always had an oil comsumption problem. Cold starts always had a white/blue hazy mist out of the exhaust. I had tons of oil in the intake from the crankcase from blow-by. Installing a catch-can actually made me smoke from the exhaust (pressure loss in crankcase). Always smelled like burnt oil after boosting. Watch my dyno video that Matt took and you can see blue smoke from the bay after each pull. Pan was always saturated in oil and I could never find the leak. Compression always read very high (sign of bad rings)
So the engine was never up to snuff.
But my problem was probably cause I was boosting the hell out it it on a 90° day. I had the a/c on, and I was running 3psi more than I've ever run. I was also running the same spark angle at 15psi as 12psi, I have no doubt I had pre-ignition and the rings just couldn't handle it.
I was slowing for a slow light and the thing went to zero rpms. It wouldn't start up and everything made me think "blown coupler." eventually I wound up calling a tow-truck cause I couldn't find the source. I was getting spark, the plugs from what i could tell looked fine (looking down on them), and now blown couplers (and duh I'm on a MAP sensor).
After about 20-30mins of sitting there waiting I tried to start it up again, it barely caught but it turned over. but then the smoke came...drove it home about 3 miles with constant streams of smoke. I knew exactly what it was, the rings finally let go.
I partially blame my tune because I never tuned my spark rows for the extra bump in boost, but I mainly blame the condition of the engine.
I'll have it back on the road, it's really not a big, just a waste of time.
My problem was my engine was a JDM import with history unknown. With that said, I've always had an oil comsumption problem. Cold starts always had a white/blue hazy mist out of the exhaust. I had tons of oil in the intake from the crankcase from blow-by. Installing a catch-can actually made me smoke from the exhaust (pressure loss in crankcase). Always smelled like burnt oil after boosting. Watch my dyno video that Matt took and you can see blue smoke from the bay after each pull. Pan was always saturated in oil and I could never find the leak. Compression always read very high (sign of bad rings)
So the engine was never up to snuff.
But my problem was probably cause I was boosting the hell out it it on a 90° day. I had the a/c on, and I was running 3psi more than I've ever run. I was also running the same spark angle at 15psi as 12psi, I have no doubt I had pre-ignition and the rings just couldn't handle it.
I was slowing for a slow light and the thing went to zero rpms. It wouldn't start up and everything made me think "blown coupler." eventually I wound up calling a tow-truck cause I couldn't find the source. I was getting spark, the plugs from what i could tell looked fine (looking down on them), and now blown couplers (and duh I'm on a MAP sensor).
After about 20-30mins of sitting there waiting I tried to start it up again, it barely caught but it turned over. but then the smoke came...drove it home about 3 miles with constant streams of smoke. I knew exactly what it was, the rings finally let go.
I partially blame my tune because I never tuned my spark rows for the extra bump in boost, but I mainly blame the condition of the engine.
I'll have it back on the road, it's really not a big, just a waste of time.
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