Retrospective LS1 Automatic w/315's on back
 

I got a lot of useful information from this website, Nathans website and Jim Stainer's Site so I figure I should pay back some of the info. I am a pharmacist not an auto mechanic. I live in Tyler TX and I love my wife, kids, house and showing off my car.

I know there are probably better ways of putting a car together but I did it with a 4 inch grinder, a cracker box welder, a $79 (with coupon) harbor freight welder and hundreds of trips to my home computer to search for answers. If I build another one (which I probably will when my son gets home from the Navy) the project will be cheaper and faster to complete. Cheaper because I bought some parts that were later upgraded and faster because I would not have to do some of it 2 or 3 times before getting it right. I don't necessarily think the end product would be much different from with I ended up with.

I will try to post all of my mistakes and how I corrected them so you won't repeat the same mistakes. It will take me a month or so to get all of the info up here because the car is still a work in progress and the fish have been biting lately.

I have not posted anything on this site before so be patient with me....

I searched craigslist for a couple of years hoping to find a miata with a blown
motor and a wrecked fbody with a motor and tranny at the same time. Finally a car came along so I bit the bullet and bought it.

Motor out!!!
 

The car cost me $2000. It is a 99 model. It had an automatic tranny in it and the motor was not working. The guy I bought if from said he was sure it needed a motor because it was running fine and made a sound "like the wind" and quit. I took the motor and tranny out and found the motor only had about a pint of motor oil in it. The interior was in very good condition and the body didn't have any rust. If you are looking for a NB miata, I suggest a 2001 or newer because they have cooler headlights and front bumper covers (which I have upgraded to) They also have useable cup holders. Also look for one with little/no rust and a good interior because it is cheaper to get all of that upfront than it is to upgrade later.

The beautiful donor car
 

I work monday thru friday and missed several opportunites to purchase
different drivetrains because they would be sold by the time the weekend came around. Finally this 98 z28 came along for $3500 and I took a day off and got it. The guy said he had over a hundred people call and ask about it and
several say they were on the way with the money. I think he was shocked when I showed up with the cash but not as shocked as I was to find this "deal" 2 hours away from my home. The transmission had been rebuilt and the motor seemed really strong. It was a really beatiful car and a lot of people asked my why I would even consider whacking it up. My mind was made up and I have no regrets. I sold the car minus the motor, tranny, computer and wiring harness for $1200.
If you are looking for a donor car, the 98 and 99 have an inferior computer. I got lucky and this one had been switched out for a 2000 model computer!

motor and tranny removal
 

Next we removed the goodies from the camaro. It took 4 hours with a lot of help from one of my friends. The old guy in the picture is my dad and the young guy is my sons best friend who helped a lot. THANKS!!!! We watched this youtube video on my phone

LS1 Engine Removal in an F-Body - YouTube

. We would play about 5 seconds of it then do a little bit of work then repeat. It wasn't that hard. The trusses in my shop held the weight of the car just fine. I wouldn't want to try lifting the car with the motor and subframe in it that way!

FYI...that is Caleb in the picture. He helped me a lot on this project..THANKS.
The old guy with the funny hat is my father. I live on a good fishing lake and he came over to go fishing. It was a sunny day and he wanted protection from the sun so he wore the funny hat. I took the pic.

Motor is headed to get "checked out"
 

I have a good friend that is an auto mechanic. Rebuilding transmissions is his specialty but he can fix anything. We took the motor to him to do a compression check. It passed the test. He found that it leaked on all cylinders when it was a top dead center but was ok a little before or after top dead center. He concluded that it had a cam in it that caused one of the valves either the intake or exhaust valve to not be closed at that point. Anyway we went with it since the tranny was "rebuilt" and the compression was good.
I got about 2000 miles on the car and the transmission started slipping and the radiator was puking antifreeze because the compression was leaking into the water system thru a bad head gasket. I think the head gasket issue was due to an overheating situation caused by a radiator hose issue. Anyway... if you have lots of money and don't want issues down the road, there is never an easier time to check out a motor and tranny than when it is out of the car the first time.
I wasn't too sad about it cause it gave me an excuse to put a 2400 stall vigilante converter in it and a g5x1 cam from LG Motorsports which woke it up quite a bit.

Making room for the motor
 

Next I removed the portions of the frame that everybody else says must be removed. I got some thin metal to fill in the holes. I did not remove my dash....that would be no fun at all. Remember when you weld up these spots that the other side of the firewall will get red hot. I just pulled the carpet back inside the car and welded about a half inch at a time then let it cool. I think I even sprayed water on it. Nothing caught on fire.

I just looked at the car and the frame removal on the driver side was totally unnecessary and the removal on the passenger side was not needed either. The passsenger side could have been fixed with a sledge hammer on the innermost part of it. The fuel line would need to be at a different place or perhaps drill a half inch hole thru the frame brace and put some rubber grommets to protect the line. I have an AUTOMATIC transmission and Sanderson Shorty headers.

It's funny, I feel exactly the opposite. My father just picked up a blown MSM to use as a 2.0 test mule and the only thing I can't stand about it is the front bumper. IMHO, the coolest looking NA/NB is the 1999 AE. I think the 2001 front is just too angular looking. To each his own, right?

Good buy though at $2000! Best of luck with your build,

-Jason

great idea on the tips. Hindsight is always 20/20. I anticipated wanting more when I put mine together so I'm building the engine and doing everything I can imagine from the get go.

what color is that front bumper
i'll find him one in the same color and trade lol

Cleaning up the front
 

Next I took out that piece of metal that goes across the front of the car and connects both halves of the frame together. A friend of mind showed me how to drill out all of the spot welds to get the pieces out (otherwise I would have made a big mess and bent up a bunch of it)

Preparing the front subframe
 

Next I whacked out the parts of the subframe that were in the way. I pretty much did what others have done. I used a 4 inch grinder and eyeballed it. Then I welded 1/4 inch thick plates to the sides. The front at this point was still in tact. I highly suggest a bar connecting both sides and don't even think about taking it off until you are done. Also....do a whole bunch of tack welds otherwise the molten metal cools then draws up and the thing won't bolt back into the car. I learned the hard way and had to get a winch on it, ungrind some welds and re-weld parts of it.

front frame prep
 

Here are those tacked on braces that I removed too quickly. Tack those suckers on before you do any welding and leave them on until all welding is
done and you are ready to clean up and paint it.

Here's what I did before I put the steel plate in. I think it is 1 1/2 square tubing.

You can see where the square tubing is and the 1/4 inch steel plate above it. Originally I just put the steel plate in there but I think the square tubing adds some lateral strength. You can see the cheap Harbor Freight sandblaster I used. I put a tarp in the back of my trailer seen in a previous picture to serve as my sandblasting booth. It allowed me to reuse the sand over and over. By the way...I found that sandbox sand worked just as well as the expensive black blasting material. Just make sure it is dry. Once it gets moist, it doesn't flow out of the pot very well.

I later replaced that weak looking stock piece of metal across the front frame with square tubing. I think it is much stronger and looks a lot better. Notice that the mounting brackets for the steering rack are welding on the square tubing. They are at the exact location they were before......I later moved them a little toward the drivers side so that my steering shaft would clear my headers. I didn't want to "dimple" the header and decrease flow. That made the car turn very sharp to the left and not so well to the right so I lengthened the right tie rod end and shortened the left one. That was fun. Shortening the left one required me to grind some metal off it to get it the right diameter then running a die on it to get more threads and cutting off about 3/4 inch that needed to be gone. I cut the right tie rod in half and welded a 3/4 piece of material into the void. I cut a groove into all pieces so I would get good weld penetration after welding all of the pieces together I clamped a 1/2 inch piece of angle iron across it and welded it up like a splint. If you do this, don't forget to put the rubber boot on first because it won't go over angle iron after the fact and keep some water there to cool the parts and weld in short segments otherwise your rubber boot will melt.

Be sure you're EXTREMELY careful when using playground sand. It is silica, and when using it as a blasting media can cause silicosis, which is deadly. You need to be using the proper PPE including a hood and good quality respirator (not a little white breather mask)

Good advice I used one of those respirators with the canisters on each side. Those respirators seal up around you face much better than the paper kind which seem to be a waste of time and money to me.

Too bad I didn't know how you felt about bumpers sooner. That could have saved me a lot of money in my attempt to make it look a little more like a
honda 2000. Here's a pic so anybody reading this can compare to the earlier picture of the car before I changed out the front. BTW...the stripes are plastidip paint. I just put them on there to see if I liked them. I will eventually paint the same scheme with a color that matches my boss frog double hoop rollbar a little better. I got the headlights on ebay. They have halo lights on them and cost about $250 for the pair.

Suspension bushings...
 

We sandblasted and painted the front and rear subframes and control arms while they were out of the car. I used black glossy engine paint. I didn't want heat to be an issue and a paint and body guy told me that it was a better grade paint vs the other rattle cans.
We also installed Prothane polyurethane bushings. Here is a good write up on how to do that with grease fittings. Mission Purple Part 2: Powerflex Poly Bushings Miata Installation The Prothane bushings have grooves on the inside of the polyurethane that allow the grease to flow from the middle of the joint where the grease fitting is installed to the ends of the bushing where it prevents squeaking. The "Energy" brand ones that I installed on my z28 did not have these grooves and it looks like the purple ones in the writeup also don't have the grooves based solely on the photos in the article. The grease may get there by moving between the sleeve and the polyurethane but I can't say because I didn't install grease fittings on the z28 and I have not actually seen the purple bushings in person. If I were to do it again, I would get the Prothane brand and not worry about it. By the way...my miata has ZERO wheel hop or slack in the suspension and it goes around corners like it is a rollercoaster on a track.

Motor Mounts
 

I read a lot about problems that occur with LS1 motor mounts. First they can come unglued. Second they can melt from the header heat. I didn't want either problem so I came up with something different. My dad suggested that I just build a solid motor mount but this was going to be my daily driver so I didn't go that route. First I cut out some 1/4 inch steel plate and drilled 4 holes in it so it would bolt up to the block. Then I ordered a couple of 1 1/2 inch bushings from a offroad vehicle website. See picture..

Here's a piece of advice if you are going to build one of these....
Get a 3 ring binder with a lot of dividers. Keep all of your receipts and notes in it. You will forget where you bought some items. Some things may break and you will need to return them. The wiring diagrams for the PCM show wire colors, the wiring diagrams for the miata show wire colors but... what color are the wires you use to connect all of the things together and where are those connections? Where are all of the relays you will install located? Believe me when I say... you will spend a lot of time looking up stuff, get the car going and wish you had made notes on those things so that later if something malfunctions...you would have a manual for your car.

motor mounts continued...
 

Next I cut some pieces of 1 1/2 tubing and some pieces of 2 inch tubing. I removed the polyuretane bushing and did some welding. The 1 1/2 inch tubing at this point slid inside the 2 inch tubing. I did it this way so I could jack the motor up or lower it down to get it just right.

This picture of the subframe shows the ears I welded on it to accept the bushing end of the motor mount. Keep in mind my car has been on the road for several months now and I am going back and telling the story. There were many revisions and I bet I painted that sucker 3 different times. I am omitting many revisions to the project and just including the parts that ended up in the finished project. Anyway.....This allowed the polyurethane to be as far away from the headers/exhaust pipe as possible and they type of bushings I used are not glued to a metal plate so I should not have either failure. Yes I am aware that the one on the passenger side is a couple of inches more forward but I think the header dictated that plus I have more room to get the starter in/out.

motor mounts
 

I put the engine/tranny in the car as far back as possible and put it on some blocks. I made sure the hood would close. It wouldn't. I removed the sway bar, lowered the motor a little more and it would close with about 1/8 inch between the top of the MAF and the bottom of the hood. Keep in mind I am still using the Z28 oil pan on the engine. I just couldn't bring myself to spend several hundred bucks for an oil pan when I had one that worked just fine.
My first plan was to have a hole thru both pieces of square tubing and put a bolt thru it. That seemed a little wobbly so I trashed that idea and welded up the holes. That route probably ended up giving me a better product since it now has a giant spot weld where the holes were. LOL

motor mounts
 

Here you can see the motor mounts in the subframe waiting to bolt up to the block. There you have it... a pair of motor mounts that won't melt or come unglued. I think the bushings were about 20 bucks and the metal was probably around $50 with lots of metal left over. I found it cheaper to go to the steel yard and purchase full lengths of metal vs going to a welding shop and buying cut lengths.

Stabilizer bar relocation
 

I made these brackets out of angle iron so I could lower my stabilizer bar and still use my stock camaro ls1 oil pan. The ears sticking out bolt to the frame and the apex is where the stabilizer bar mounts.

The ones on the left are the stock ones. The ones on the right are the ones I made. Which ones do you think would "stabilize" better. And yes...the new ones weigh more...probably a pound each. I bet it and my motor mounts slow down my 1/4 mile ET by one millionth of a second.

I also attached a picture of the bracket installed.

transmission crossmember
 

I installed some v8 roadster frame rails to strengthen it up a bit then built this crossmember out of angle iron and square tubing. I also used a section of
pipe from a fence post driver I had laying around for the place where the exhaust pipes go under it.
The same bolts hold the frame rail and crossmember in.

Wiring
 

I did all of the wiring on my car and used the harness that came with the camaro. Here are some things I learned...

1. Connections that are soldered and heat shrunk are better than twisted wire and black tape.
2. 3M black tape is a lot better than the stuff you get for a dollar
3. You can put all of the orange wires together and hook them to "hot all the time" and put all of the pink wires together and hook to "power with ignition" but how safe is it? If I were to do my car all over again, I would have a fuse panel with separate circuits going to the injectors, coils, 02 sensors etc with very small fuses protecting the small wires.
4. The only wires you need to label before pulling your 4 cylinder motor out are the ones for the starter and the one going to the temperature sending unit. (leave the connector on that one and save the sending unit)
5. I used a dakota box for the speedometer and the tach. It saved me money because I have already used 3 different sizes of tires and didn't need to pay a tuner to make my speedometer accurate.
6. You could leave all of the unused wires in your harness and just have some unused connectors or you could spend many hours removing them and have a cleaner apperance under the hood. Or...you could just cut off the unused connectors and cap off the ends of the wires with heat shrink...that would save a bunch of time.
7 LT1swap.com is an excellent source of info for wiring. There are a couple of LS1 sites with good info too.
8. The PCM uses small amounts of current (sometimes small grounds) to control things like the AC compressor and the fans. You will have to use relays to get enough current to operate these.
9. The easiest way to hook up the gauges is to get a wiring diagram for your car, find the appropriate wires where they hook into the gauge cluster then go from there to your dakota boxes or pcm.
10. GM used the same type of connectors for the Cam Position Sensor, Crank Position Sensor and MAP sensors. Label them and dont get them mixed up...otherwise the car wont start. If your harness is already out of your donor car...trace them back to the PCM pinouts to figure out which ones they are. Again.. LT1swap.com has all of the info you need to do this

I wired mine up and you can too...just be willing to spend lots of time looking up answers and be willing to take a break from it often.

Here are some pics of the rear subframe with the 03 cobra 31 spline aluminum differential. Others have described how to do this so I won't go into it other than to say that I put some heavy duty metal into it and burned lots of welding rods.

One huge piece of advice I would give here that I didn't read anywhere else...
The Pinion shaft should not go exactly in the center of the subrame assembly. I didn't know this and centered mine. The differential is made such that the pinion shaft should be about an inch closer to the passenger side...not centered!!!!
I figured this out when my half-shafts came in. One of them was too short and one of them was too long. It took a while to figure this out. When you are finding the right spot for the differential you should either get your half-shafts and install them in the assembly to find the right spot OR you could measure from the hubs to the inside of the differential to that little bar inside where the half shafts go or to the seals that go around the halfshafts.

thedriveshaftshop.com was very helpful and did what it took to get me going...one axle is an inch shorter than what they normally sell and the other is an inch longer. They also made my driveshaft. They do top quality work!!!

Diffrential with driveshaft centered
 

I promise that the pinion shaft is in the exact center of my car. The back part of the transmission tunnel on the miata is also designed to have the pinion shaft offset one inch. I just had to beat the crap out of that part of the tunnel so the u-joint assembly would not rub. If I had it to do all over again...I obviously would do it with it moved over an inch but by the time we figured out what happened...One of my axles had been shortened so it was easier to lengthen the other one than it would be to get both of them re-made.

radiator mounted
 

I used some thin 3/4 inch angle iron to make a radiator frame that bolts to the miata frame rails on each side.
I got a Griffin radiator from Summit. It only has 2 rows in it but it is 3 inches thick! The first Griffin radiator I put in leaked. The guy at the radiator shop said it was faulty from the factory. It was leaking on both sides where the rows go into the tanks. I read online that some folks had a hard time dealing with Griffin. I highly recommend buying from Summit. I called them and they had the replacement on the way before I even got the call tag from them to ship the defective one back.

Power steering and tranny coolers
 

Next I mounted the transmission cooler and power steering cooler.

A/C condenser
 

Next I mounted the AC condenser. The dryer didn't work in this location. It hit the bumper cover. I unhooked it then carefully bent that skinny line so that the dryer ended up medial to the driver side headlight. That line was a lot less brittle than I especte but I still managed to get a pinhole in it were it mounts into the tank. The welding shop only charged me $15 to patch it up.

I had some lines made up that were miata on one end and z28 on the other end. I used the stock a/c compressor in the stock f-body location. I did put a new compressor on it and burned it up.

It is important to let the pcm control those stock compressors. (you will have to get a chevrolet pressure switch which can screw into the location where the miata pressure switch was...with an adapter fitting) The GM variable output compressors are not designed to run at high rpm's so the pcm will automatically turn it off to prevent self destruction.

I started out with a toggle switch inside going directly to the a/c compressor. It worked fine for a little while. After replacing the first new compressor with another new one... the toggle switch now tells the pcm to turn on the compressor.

Another mistake we made....when I installed the second compressor...it wouldn't get very cold even though the pressure gauges said freon levels were good. It turns out that we put another can of oil in it resulting in too much oil. To fix it, we replaced the dryer (which was full of oil), charged it up with 2 cans of refrigerant and it was ice cold!!!j

Fbody fans on my miata
 

I measured and the distance from the outermost part of one fan to the outermost part of the other fan on my stock LS! camaro setup was about 1/4
inch more narrow than the radiator. I had to make it work. Those suckers pull a lot of air. I cut off the part I didn't need, put some duct tape around the edge then started laying fiberglass around the edges. It took a while to do this because I could only do the part that was horizontal. (fiberglass resin runs dowhill before it gets hard). I didn't know about Bondo Glass at this point. If I was to do it all over again, I would use some of that and it would be much easier.

Once it was made, I put it on the radiator, wrapped it in gorilla tape and called it good. I bet it pulls more air than those setups folks are spending hundreds of bucks on and I would say it was free since I already had it with the donor car.

radiator and fbody fans in car
 

Here is how it looks from the top. There is about 1/4 inch clearance between the fan motors and the serpentine belt. I later notched the stock piece of metal over the radiator to allow for an air snorkel. (I guess that is what you call that piece of plastic that joins the MAF sensor to the air filter)

top radiator bracket
 

Here's that stock piece of metal that goes over the top of the radiator once I notched it. It is needed because it has a couple of holes that hold the front
bumper cover on.

air filter installed...
 

I used the snorkel off a corvette that I found on craigslist for a good price on craigslist. The air filter and the T-pipe were purchased on Ebay brand new pretty cheap too.

I ended up putting a piece of 1 inch angle iron behind the air filter connecting both half of the frame. It also allowed me to zip tie the air filters to it for more stability. I also bent and spray painted an old license plate which was bolted to the angle iron on each side and curved up to prevent water from entering the bottom part of the air filters.

hood up....
 

Here's what it looks like with the hood up....

hood down....
 

And with the hood down...

The air filter is in that space between the top corner of the license plate and the medial portion of the headlights. They actually protrude into the top portion of the air opening for the radiator about 1/4 inch but I bent up an old license plate and put over the bottom part of the air filter so it won't suck up water if it is being driven in the rain. There is plenty of space between the bent up (spray painted) license plate and the air filter so that it does not impede air flow.

In a future project I will take off the corvette snorkel and make something out of fiberglass that flows more air. I think that pinch point limits the air flow a bit. Maybe not...GM engineers may have known what they were doing when they designed it.

UPDATE!!!!...fast forward to 6/2/15 to see modification.

Shifter
 

I tried to use the stock fbody shifter but it just wouldn't work with the amount of space I had to work with.

I found this one from a company called Lokar. I like the way the stock shifter works much better than this one but this one looks good in the car and if you just need something to put it into drive, reverse and park...this one works great. If you are wanting to manually shift from first to second, third and 4th... it is very awkward to use and perhaps a ratchet shifter would be a better option.

Attached are pics of the angle iron I cut to mount the shifter to the transmission tunnel as well as the finished product.

I used silicone to attach the boot to the stock plastic ring that goes around the stock shifter...it worked great. There was quite a bit of heat coming in around that area until I took some pillow packing material and filled up that area under the shifter boot. Once I did that ...problem was solved.

heat shield...
 

I bought a piece of heat shield that was about 2 ft by 2 ft and put it in the transmission tunnel. I also purchased some stuff similar to dynamat and covered the entire floorboard. I can't tell you where I bought that stuff because I didn't keep the receipts in a notebook. LOL I wish I would have installed the heat shield material before installing the frame rails because the bolts are covered up. No big deal just not optimal if you need to remove the crossmember later (which I did)

tires...
 

My miata had some stock 16x6.5 inch rims. Attached is a pic of the tires I have tried. The far left one is what was on the car when I bought it. The tires were new with about a half inch of tread on them. They lasted about two weeks. The widest tires I could put on those rims was a 245. They gave a lot better traction but even after rolling the finders with a baseball bat...they rubbed when I went around corners fast. The one on the far right is 315 35 17 and they only cost 140 bucks each and I currently have on the car. It handles like a dream and hooks up very well. It required a lot of work on the fenders which I will detail in the next 15 or so posts....

Wheels...
 

I bought some rims off ebay. The fronts are 16x8 the rears are 17x10. I know....this is an "unbalanced set"...well....GM put rims on corvettes that are 1 inch smaller on the front....so I did. They only cost 620 for all four rims.

I didn't like the unused 4 bolt holes so I put some "dummy" bolts in there and now it looks like I have 8 lugs holding my rims on. LOL I just bought some extra wheel studs, did some grinding on them, some countersinking on the wider bolt pattern from the back side then put the "DUMMY" lugs on. Notice the wheel even off the car has 4 lugs on it. Funny huh? Yes...I know...this adds un-needed weight to the car and it probably slows me down another millionth of a second in the 1/4 mile ROFL

wheel on car
 

So this is what the wheel and tire looked like on car. It obviously would not work even after "rolling" the fenders. I would be one pothole away from a flat. Ha Ha

tires too big...
 

So I started by measuring how wide the fender flares needed to be....

fender flare project begins....
 

Next I put some tape on the fender and placed some cardboard in the fenderwell based on the measurements I took.

You should place a black line on the tape where you want the flares to end. You can take a lot of measurements and get each side identical.

making big fenders...
 

Next I sprayed on some of the Great Stuff foam that you can get at Home Depot.

It's important to limit your spray to about 1 1/2 inch thickness. Let it cure for a couple of hours then go over again and repeat until you get the thickness you want otherwise the foam below never cures and it is a gooey mess!!

big fenders....
 

Next I cut the foam with a saw blade knife I purchased at Harbor Freight for about 3 bucks. Then I drew some lines on it then started cutting foam away that didn't need to be there.

shaping the foam...
 

Once you get the rough shape cut...use an orbital sander with 80 or rougher grit sandpaper to shape the foam like you want it. Remember to do the same steps on the other side as you go. If you complete one side then try to do the other side....good luck getting the same shape.

This is what it looked like. I stepped back from it and decided it looked too much like the fenders were stuck on the car and not part of it. It looked a little like I bolted on some dually fenders LOL.

More foam....
 

I decided that a gradual transition from the flare to the top of the fender might look better.

I drew a new black line on my tape so I could keep both sides the same, sprayed more foam then got the knife and sander after it again.

big fenders continued...
 

Next I put masking tape over the foam.

Then I put a layer of fiberglass on the tape. I used the cloth type of mat followed by a layer of the mesh type followed by another layer of cloth type. I don't like the mesh type...it gets very messy but I think it adds strength. I found it easiest to put on a bunch of 4 inch by 4 inch pieces otherwise the curves of the fender ended up causing wrinkles with voids under them.

I bought a 50 pack of red solo cups, a box of disposable brushes from Harbor Freight and a box of vinyl gloves as well. That made the process a whole lot less messy.

Once the fiberglass cured...I popped it off the car then took all of the foam out. I wasn't able to get all of the blue tape off the inside but I don't think it really matters.