LS1 Miata Build Thread by fourwhls

10 minute(s) of a 124 minute read

First Track Day = BIG FAT FAIL

Clutch

Clutch is still an issue and one that I just don't understand. Grinds between gears and slips 

Driving around as if I were driving on the street and everything works fine.

Get on it hard and it acts like I'm not pushing the clutch in far enough and doesn't allow me to upshift or downshift.

So I stick it in 4th gear and let it eat hoping to at least get a little fun out of the event....Then the clutch starts slipping on lap 3 

I bled and bled the clutch between sessions. I re-adjusted the pedal to ensure there was no preload and just a slight bit of free play before engagement.

Also noticed that once the clutch started slipping, the pedal was hard. Not hard to depress, just hard as if it were preloaded, no slop at all. Take it easy for a few minutes and clutch starts grabbing again and pedal free play is back. 

Any possibility an incorrectly sized master cylinder would cause something like this???

I'm about the point of starting all over and replacing the current setup (Fidanza AL Flywheel, C5 Corvette Z06 clutch, GM slave cylinder, Wilwood Master Cylinder) with matched and proven setup. I just don't know.

Differential Seals

The diff seals were leaking after a local autocross, so I bought some new OEM Mazda seals and swapped them out. I ran the car on the dyno afterward and didn't see any new fluid, so I assumed I had fixed the problem. NOT...

Looked under the car when I got home and gear lube was everywhere. I just hope I didn't loose so much that I damaged the rear end.

Time to pull the rear back out of the car for a thorough inspection of the gears, stub shafts and seals.

Power Steering Pump

Power steering fluid got so hot after 4 laps that I lost power steering all together. Came into the pits and fluid was everywhere.

Time to look into either a cooler, turn one pump again, or both.

Vibration

During the last session, the car started vibrating pretty bad at the top of 4th. Seems like something came apart.

Time to relax....Drink heavily....do some homework....then figure this thing out.

9/24/11

Run #4 at the Autocrossers Inc. event at Blue Crab stadium in Waldorf, Md.

The course was pretty tight, but it was fun. The car is getting faster and faster. I set the FFCTD (Fastest Fendered Car Time of The Day) with a sloppy 43.9. I did get beat by a shifter kart and a FSAE car. I ended up 12th overall out of 100 in PAX (XP PAX is brutal).

It took me 4 runs to get the car to handle half way descent. Right before the event, I went to 900lb springs up front without touching the rear and inevitably, the car was a pushing pig at first. I was able to tame it down with tire pressure and shock settings, but I'm going to need some more rear spring rate to balance the car back out.

I plan to swap out the rear 450lb springs for a set of 550s. With the big slicks and the 450s, I am bottoming out the tires on the top of the wheel wells under hard acceleration, so the 550s will likely work out pretty well.

Speaking of the BIG SLICKS. I finally got the 16x11s with 23.5x11x16 Hoosier slicks mounted last week. It took a little cutting wheel work and some BFH massaging, but they fit.

I did loose my front fender flares. I need to look at some new options for flares. Need moar bigger!

Here's some pictures of the car with the big wheels/tires:

10/5/11

Cosmetic update....

New Flares installed (tuckin the 16x11s)

-They're Tuckin99 knockoffs built by rharris19. Incredible fit and finish. I have installed 4 sets of flares on my and others Miatas and this set is by far the best fit and quality.

Built a splitter

.25 ABS

I'll have to take some more pictures of the splitter another day. I didn't take any pictures during the build.

Track Wheels and Tires (15x9s with 240/600-15 Avons)

10/10/11

Made it out to VIR this past weekend. 

Clutch seems to be fixed and working well. First session was good. I took it easy and made sure everything was OK. I found out that my valve cover vent tube leaked oil during hard right hand turns, but other than that, everything was working well.

Between sessions, I rerouted the vent line and pretty much fixed that issue. 2nd session came around and it was time to see what it had. Needless to say, I was VERY impressed. This thing pulls like a freight train.

I was able to pull pretty much anything and everything I came upon in the instructor group. I came out of oak tree about 20 car lengths behind a C6 Z06 and was able to pass him by the top of the hill. Something I thought I never would have experienced in a Miata.

The look on some of the driver's faces when they had to give a pass to a Miata on a straight were priceless. The people coming to my paddock spot afterwards to ask "what the hell is in that thing" was kinda cool.

The new aero worked really well. The car stayed planted coming over the top of the hill right at 160mph. I was expecting the front end to float, but was pleasantly surprised to have it stick. I found the limit in the uphill esses. I pushed the throttle just a little further each lap, till I was entering right about 135mph. If my timing was on, I likely would not of had an issue, but I got out of the rhythm and ended up going straight across the grass in the 2nd two esses to save it. Oops!

Unfortunately my incar video didn't work either session, so I only have a small teaser of a video. This is a quick video from the top of the concession stand.

I wish I could end this post with nothing but smiles, but unfortunately I can't. About 15mins into the 2nd session, I lost oil pressure going down the back straight. I saw the light pop on at about 6k rpms in 5th gear, then scanned over to the OP gauge reading 0psi. I popped it out of gear but left the car running to ensure that I had brake vacuum to get it stopped at the end of the straight.

Once I got the car down to a speed where I was able to hear the engine, I heard a knocking rattling mess. I shut the car down and coasted all the way to pit entrance and waited for a tow.

I'm not really sure what happened just yet, but hopefully it's not too bad. Nothing came through the block and it was still running when I shut it down, so hopefully it's salvageable.

I'll pull the engine out in the next week or two and tear it down to see what happened. It's got me puzzled, but I don't really have the money to do anything about it, so I'm not in too big of a hurry.

1/15/12

Well I guess it's about time for an update....

After avoiding the garage for a while, I finally pulled the motor apart right before the holidays and here's what I found.

#3 and #4 rod bearing are toast.

crank is done

#3 and #4 rods are done

The rest of the motor looks good. Pistons and cylinders are still in perfect condition and no damage at all to the top end.

Yes it sucks, but it definitely could have been much worse. I still don't know what caused this issue for sure. I do know that there was only a little over 10qts of oil in the system when there should have been closer to 14. High RPM on the back straight suck all the oil out of the system? Don't know and probably never will.

So how am I to fix this......duh!......add more power 

I stumbled across a really good deal on an 18k mile LS6 out of a 2004 Z06 Corvette. He cracked a piston ringland and instead of repairing, he picked up a complete long block and swapped it out.

So I am taking the best of both my LS1 and the new LS6 and putting together a new engine. 

Ported, Polished, and shaved 243 heads

ASA Cam

Balanced bottom end

stock bore, stock pistons, new rings and a hone.

Should be north of 400HP to the wheels. 

Heads are done, bottom end is at the machine shop and should be done later this week. I am traveling a lot this month for work, but I hope to have it back together in a few weeks.

Oil System:

I am going back to a stock oiling system and adding an accusump. Dry sump is cool, but complex. I'm going back to KISS. I found a company in MN that will build me a road race baffled, 6.5 qt winged pan to my specs for a reasonable price. New pan, oil cooler, accusump, DONE!

This will make maintenance soooo much easier.

I also need to plumb in a catch can, but that is the easy part.

Steering System:

I'm also going back to a stock steering shaft and getting rid of the one that I made. Not that it didn't work, it did, it worked great, but it is a royal PITA when you need to drop the engine. Again, I want to go back to KISS.

I picked up a new driver's side header and will be modifying it to go around the steering shaft.

My goal is to have the car back together and retuned by the end of Feb and back to the track in March. It's only time and money, and money, and money, Oh, did I mention money?