my LeMons car
12-28-2008, 10:09 PM
#184
Junior Member
Join Date: Apr 2008
Posts: 109
Total Cats: 16
Quick update: Race just ended. car was ******* awesome. Ran almost flawlessly, only broke once. We babied it for all but the last two hours (shifted at 6000 rpm), then we opened the full rev range and gave it hell.
End result: 2nd fastest lap of the entire race and 4th place finish out of 96 entries.
More details when we're sober.
Many thanks to those who helped. Too drunk right now to remember who they are..
-Dave
End result: 2nd fastest lap of the entire race and 4th place finish out of 96 entries.
More details when we're sober.
Many thanks to those who helped. Too drunk right now to remember who they are..
-Dave
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12-29-2008, 10:45 PM
#187
Junior Member
Join Date: Jun 2008
Location: Nottingham, Pa
Posts: 81
Total Cats: 0
I just found out who had the fastest lap at the race. A ******* crown vic! Albeit it was door-less after the peoples curse came down upon it. lol
In fact, this Crown Victoria turned the fastest lap of the entire race! That time was an absolutely stunning 1:31.474, which was nearly five seconds quicker than the race winner and more than a second quicker than the second-quickest lap (by the Eyesore Racing Frankenmiata).
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12-30-2008, 01:45 AM
#190
The race was spectacular. It turns out we led the race for more than 70 laps. That is freakin ridiculous for a lashed-up jalopy like ours. Our 4th place finish was behind some very seriously fast hardware, and we were not behind not by much--after fourteen hours of racing, we were one lap out of 2nd place.
We had the time of our lives out there. Again thanks to all the guys on this forum who helped us out with this build. We absolutely couldn't have done it without you. Cheers to you.
We had the time of our lives out there. Again thanks to all the guys on this forum who helped us out with this build. We absolutely couldn't have done it without you. Cheers to you.
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12-31-2008, 03:19 AM
#194
Junior Member
Join Date: Apr 2008
Posts: 109
Total Cats: 16
I was REALLY confused the first time I hit the brakes and got a mirror-full of blue trunklid...
-Dave
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12-31-2008, 03:23 AM
#195
Junior Member
Join Date: Apr 2008
Posts: 109
Total Cats: 16
Before the people's curse, that was a very well prepped car with a manual trans (despite the claim it was an ex-cop car) some impressive on-track dynamics (looked better than cop shocks...) and very little weight. It was very gutted, had all-lexan windows, etc., and naturally, had tons of power.
It didn't lay down that scorcher lap until after the people's curse removed the dead weight of all the doors, hood, trunk and part of the roof, and removed the aerodynamic penalty of a windshield.
I still don't know how they did it. I was driving the ***** off our car when I set our fastest lap. No mercy...
-Dave
It didn't lay down that scorcher lap until after the people's curse removed the dead weight of all the doors, hood, trunk and part of the roof, and removed the aerodynamic penalty of a windshield.
I still don't know how they did it. I was driving the ***** off our car when I set our fastest lap. No mercy...
-Dave
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04-13-2009, 02:27 AM
#197
Junior Member
Join Date: Apr 2008
Posts: 109
Total Cats: 16
Latest update: We tore down the engine this weekend looking for a noise that some thought sounded like a rod knock, some thought sounded like piston slap, and some (me) thought we should just ignore and keep racing.
It's been making a subtle, but increasingly persistent and nasty noise at part throttle and it's been filling its oil filter with metal ever since we first assembled it from a stack of shitty old broken Miata parts. We did about 3 hours of track time before the first time someone thought they heard rod knock. We couldn't duplicate the noise, so we wrote it off as in-helmet acoustics.
We pulled the first oil filter at about 7 hours and found this:
Still couldn't make the rod noise, and we were out of time, so we went ahead and raced.
Halfway through the race, we started noiticing the rod knock noise from pit lane as the car went by on the straight! But only during yellow flags. On boost, the engine was silent and smooth. When we pulled and cut the filter at the halfway point, there was a lot less metal than before, so we decided to go ahead and drive it like we meant it (we had been short shifting at 6000 ever since the first filterfull of metal). Finished the race with no drama (other than almost winning and almost setting fast lap).
One more filter, a little more metal, and finally we could duplicate the noise. If you revved the engine, it would make the clatter for just a second at the top of the rev. None while revving up, none while coasting down, but a little clatter right at the top. Ron Bergenholtz was standing nearby for one of our clatter tests and he said it sounded like piston slap. That actually made sense, since a turbo motor always has positive pressure on the top of the piston when its on boost, but when there's vaccum in the manifold, the pressure delta across the piston goes negative on the intake stroke and positive everywhere else. If you have an ancient block and pistons, maybe the piston-to-wall clearance would open up enough that the pistons could rock back and forth?
After this diagnosis, we did another 6 hours on track at Laguna Seca.
In total, we think we've got 33.5 hours of track time on this engine, at least 30 of which were after the first time we thought we heard rod knock.
So, this weekend's teardown? No cam bearing damage. Piston skirts look fine. Cylinder walls look quite worn (hone marks gone in 30 hours!), but nothing that would shed metal. Rod bearings? oh...
All four look like this.
How he hell did we manage 30 hours of track time with bearings that looked like this?
1: dumb *** luck.
2: during assembly, we picked up a washer off the floor and slipped it under the oil pressure relief spring, kicking up oil pressure some random, unconfirmable amount.
3: Before the race, we went through the oil shelf in my garage and dumped every half-used bottle of oil into a jug and poured the concoction into the engine. Since we usually use the good stuff in our other cars, a lot of those partial quarts were synthetic. I think the mix resulted in something like 7W39 quasi-syntheitc. That probably saved our asses...
Those bearings had less than 60,000 miles on them when we installed them, and we put them with the crank they originally knew (though not necessarily on the same journals...) So maybe you shouldn't move used bearings around?
Thanks to wholesale parts discounts from our lone sponsor, MD Automotive, we just spent $15 on a head gasket, $25 on new rod bearings, and $3 on oil pan gaskets and put it back together. After a race, if your car survives, you can ask Jay Lamm for a value on your car. He said ours was worth $275, leaving us $225 to spend before the next race. Since this weekend was half-price weekend at Pick Your Part, we ran over there, found a Volvo 240 turbo, and snagged the oil cooler ($8), lines (2x$4=$8), and sandwitch adaptor ($free! they didn't notice it). I think we'll be back on the track for $59.
-Dave
It's been making a subtle, but increasingly persistent and nasty noise at part throttle and it's been filling its oil filter with metal ever since we first assembled it from a stack of shitty old broken Miata parts. We did about 3 hours of track time before the first time someone thought they heard rod knock. We couldn't duplicate the noise, so we wrote it off as in-helmet acoustics.
We pulled the first oil filter at about 7 hours and found this:
Still couldn't make the rod noise, and we were out of time, so we went ahead and raced.
Halfway through the race, we started noiticing the rod knock noise from pit lane as the car went by on the straight! But only during yellow flags. On boost, the engine was silent and smooth. When we pulled and cut the filter at the halfway point, there was a lot less metal than before, so we decided to go ahead and drive it like we meant it (we had been short shifting at 6000 ever since the first filterfull of metal). Finished the race with no drama (other than almost winning and almost setting fast lap).
One more filter, a little more metal, and finally we could duplicate the noise. If you revved the engine, it would make the clatter for just a second at the top of the rev. None while revving up, none while coasting down, but a little clatter right at the top. Ron Bergenholtz was standing nearby for one of our clatter tests and he said it sounded like piston slap. That actually made sense, since a turbo motor always has positive pressure on the top of the piston when its on boost, but when there's vaccum in the manifold, the pressure delta across the piston goes negative on the intake stroke and positive everywhere else. If you have an ancient block and pistons, maybe the piston-to-wall clearance would open up enough that the pistons could rock back and forth?
After this diagnosis, we did another 6 hours on track at Laguna Seca.
In total, we think we've got 33.5 hours of track time on this engine, at least 30 of which were after the first time we thought we heard rod knock.
So, this weekend's teardown? No cam bearing damage. Piston skirts look fine. Cylinder walls look quite worn (hone marks gone in 30 hours!), but nothing that would shed metal. Rod bearings? oh...
All four look like this.
How he hell did we manage 30 hours of track time with bearings that looked like this?
1: dumb *** luck.
2: during assembly, we picked up a washer off the floor and slipped it under the oil pressure relief spring, kicking up oil pressure some random, unconfirmable amount.
3: Before the race, we went through the oil shelf in my garage and dumped every half-used bottle of oil into a jug and poured the concoction into the engine. Since we usually use the good stuff in our other cars, a lot of those partial quarts were synthetic. I think the mix resulted in something like 7W39 quasi-syntheitc. That probably saved our asses...
Those bearings had less than 60,000 miles on them when we installed them, and we put them with the crank they originally knew (though not necessarily on the same journals...) So maybe you shouldn't move used bearings around?
Thanks to wholesale parts discounts from our lone sponsor, MD Automotive, we just spent $15 on a head gasket, $25 on new rod bearings, and $3 on oil pan gaskets and put it back together. After a race, if your car survives, you can ask Jay Lamm for a value on your car. He said ours was worth $275, leaving us $225 to spend before the next race. Since this weekend was half-price weekend at Pick Your Part, we ran over there, found a Volvo 240 turbo, and snagged the oil cooler ($8), lines (2x$4=$8), and sandwitch adaptor ($free! they didn't notice it). I think we'll be back on the track for $59.
-Dave
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04-13-2009, 09:58 AM
#198
So what lemons event you going to next? I'd like to make it to CMP in Sept but I won't bring another Miata. The hate fro these little cars is hard to overcome. But I guess they have a point when our 5 drivers have NEVER been on a road coarse before (4 never drove the car before that day) came in 24th. Just a testament on how good a car these bone stock Miatas really are.
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11-01-2009, 01:14 AM
#200
Junior Member
Join Date: Apr 2008
Posts: 109
Total Cats: 16
Hey kids,
The whole story of the engine build is up on MotoIQ.
The FrankenMiata Geek Hub > MotoIQ > Magazine Articles
When I get my crap together, I'll finish the stories on the coolant re-route, suspension tuning, and fusing two miata chassis into one.
We're headed to Thunderhill in a couple of weeks for the car's 4th outing. Just dyno tested it today and it makes EXACTLY the same power it made a year and 3 races ago.
-Dave
The whole story of the engine build is up on MotoIQ.
The FrankenMiata Geek Hub > MotoIQ > Magazine Articles
When I get my crap together, I'll finish the stories on the coolant re-route, suspension tuning, and fusing two miata chassis into one.
We're headed to Thunderhill in a couple of weeks for the car's 4th outing. Just dyno tested it today and it makes EXACTLY the same power it made a year and 3 races ago.
-Dave
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