1968 GTO LS1/T56 Conversion
Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
It's been cold outside, and motivation dwindled. I have made a little progress, though. I started to patch the transmission tunnel. I got a sandbag, a mallet, and some steel and started to go to town. It's slowly coming along. I am surprised at how easy it is to give the steel a nice curve.
I spend a lot of time modifying the stock transmission crossmember, but then discovered that it is too rotted at the ends to be reused. I am thinking that I will make my own, but another option is to modify a Chevelle one. Those seem easier to work with.
I spend a lot of time modifying the stock transmission crossmember, but then discovered that it is too rotted at the ends to be reused. I am thinking that I will make my own, but another option is to modify a Chevelle one. Those seem easier to work with.
Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
Can someone explain how they made their clutch cylinder bracket from this 'template' that is not drawn to scale? I am starting to take measurements to design my own, but I see that many people have used this sketch.
Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
I decided to work with the transmission crossmember that I have. I cut off the rusted ends and welded on new steel to replace them. I also raised the center portion to meet the T56 (mating surface is higher than the 4 speed).
For reference the bushings are at the frame rails on GTOs. This is different from the Chevelles. GM engineers were probably trying to achieve superior NVH for brand distinction.
For reference the bushings are at the frame rails on GTOs. This is different from the Chevelles. GM engineers were probably trying to achieve superior NVH for brand distinction.
Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
Updates....
The template for the master cylinder mount that I was questioning earlier has the hole in the right places in relation to each other, but it is not properly constrained, and the measurements on it are incorrect for my vehicle. If you use it please measure your vehicle carefully first.
New clutch and throwout bearing are in. See pictures.
Accessories are starting to go onto the engine. See pictures. During an early test fit it looked like I would not have to grind the steering box, but it is a very tight fit now. I will take a little off of the alternator and a little off of the steering box. Wiring will follow soon.
I started over on the trans tunnel. I decided that it would be easier to use as few new pieces as possible to make the smoothest tunnel. Most of the bending was performed using my leg as a form.
I also made an EGR block off plate out of 16 gauge steel.
The template for the master cylinder mount that I was questioning earlier has the hole in the right places in relation to each other, but it is not properly constrained, and the measurements on it are incorrect for my vehicle. If you use it please measure your vehicle carefully first.
New clutch and throwout bearing are in. See pictures.
Accessories are starting to go onto the engine. See pictures. During an early test fit it looked like I would not have to grind the steering box, but it is a very tight fit now. I will take a little off of the alternator and a little off of the steering box. Wiring will follow soon.
I started over on the trans tunnel. I decided that it would be easier to use as few new pieces as possible to make the smoothest tunnel. Most of the bending was performed using my leg as a form.
I also made an EGR block off plate out of 16 gauge steel.
Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
Transmission tunnel is done. Just need to get a friend or two over to help me put the transmission in.
I used self taping sheet metal screws to hold the new part in place while I welded it (and then filled in the hole to create spot welds). It is fantastic for preventing warping, too.
Sorry about how bright all of the pictures are. I will try different camera settings for the next ones.
I used self taping sheet metal screws to hold the new part in place while I welded it (and then filled in the hole to create spot welds). It is fantastic for preventing warping, too.
Sorry about how bright all of the pictures are. I will try different camera settings for the next ones.
Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
Progress updates:
After removing as much rust as possible, I used seam sealer on all of the welds to make extra sure it's water tight. After that I coated the underside of the transmission tunnel with an acidic aerosol product designed to freeze rust. I followed this up with paint, and then some truck bed liner. I wanted to use POR15, but I didn't want to wait for shipping, so I got this stuff from NAPA.
I also have painted the transmission cross-member and frame brackets (see pictures) using the same procedure as described above.
Finally, I started to install the wiring this past weekend. Tomorrow I will be installing the transmission (hopefully for the last time) and finishing my clutch master cylinder bracket.
After removing as much rust as possible, I used seam sealer on all of the welds to make extra sure it's water tight. After that I coated the underside of the transmission tunnel with an acidic aerosol product designed to freeze rust. I followed this up with paint, and then some truck bed liner. I wanted to use POR15, but I didn't want to wait for shipping, so I got this stuff from NAPA.
I also have painted the transmission cross-member and frame brackets (see pictures) using the same procedure as described above.
Finally, I started to install the wiring this past weekend. Tomorrow I will be installing the transmission (hopefully for the last time) and finishing my clutch master cylinder bracket.
Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
Engine and Transmission are in! It was pretty awesome to sit on the floor and pretend to do 1/4 mile passes.
In the last picture you can see that I extended the hole where the factory mechanical clutch linkage passes though the firewall. This is where the clutch master cylinder will pass though. As previously mentioned (I believe) I am using the S&P bracket design that I fabricated myself. I'll post pictures of that soon when it is done.
In the last picture you can see that I extended the hole where the factory mechanical clutch linkage passes though the firewall. This is where the clutch master cylinder will pass though. As previously mentioned (I believe) I am using the S&P bracket design that I fabricated myself. I'll post pictures of that soon when it is done.
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On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
I got my wiring harness cleaned up. The first picture is all the extra stuff the got pulled out. I still need to integrate the LS1 harness with my vehicle (gauges, MIL light, OBD port, etc.), but it is nice to have the harness on. I have more pictures, and can provide a list of what I removed, but I think that the sticky does a great job of explaining things.
I ordered a set of GTO fuel rail covers from another member. I think they look great.
My clutch master cylinder mounting bracket is nearly done. I welded in a piece of sheet metal to cover the hole where the stock mechanical linkage passed through. I just need to clean up the edges and paint the bracket before I put it on.
The last picture shows how the steering column interferes with installing the driver side header. The passenger side went on pretty easy after the dipstick tube was removed. As I mentioned earlier in the thread, these are the edelbrock swap headers. I am hoping to have it on today.
I ordered a set of GTO fuel rail covers from another member. I think they look great.
My clutch master cylinder mounting bracket is nearly done. I welded in a piece of sheet metal to cover the hole where the stock mechanical linkage passed through. I just need to clean up the edges and paint the bracket before I put it on.
The last picture shows how the steering column interferes with installing the driver side header. The passenger side went on pretty easy after the dipstick tube was removed. As I mentioned earlier in the thread, these are the edelbrock swap headers. I am hoping to have it on today.
Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
I do plan on using the hood tach, but I have not done any research (yet) on what that will require.
My plans for the speedometer are to either get a box that converts the electronic signal to a mechanical one, or to find an after market gauge that I can fit into the stock location with the stock face on it. I will post updates as this comes to fruition.
My plans for the speedometer are to either get a box that converts the electronic signal to a mechanical one, or to find an after market gauge that I can fit into the stock location with the stock face on it. I will post updates as this comes to fruition.
Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
I ordered a slew of Russell -6an stuff for the fuel system. There is a great reference here: https://ls1tech.com/forums/conversio...er-source.html. Hat tip to Pocket for the great work!
Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
I have the fuel lines run, and the wiring is coming along nicely. It should be done after this long weekend.
I got some radiator fans off of a 2003 Accord V6. They fit pretty good, but are a BCH too short.
For the throttle linkage I used a 2000 Camaro V8 cable. It is a little long, but it works. I also traded the GTO gas pedal for the 2000 Camaro one because it has the proper end for the throttle cable. It bolted right in.
Pictures will come on Monday.
I got some radiator fans off of a 2003 Accord V6. They fit pretty good, but are a BCH too short.
For the throttle linkage I used a 2000 Camaro V8 cable. It is a little long, but it works. I also traded the GTO gas pedal for the 2000 Camaro one because it has the proper end for the throttle cable. It bolted right in.
Pictures will come on Monday.
Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
As promised here are pictures of the honda radiator fans, my fuse box and relay bracket, and the fuel system (fuel pump and fuel filter/regulator). I have also included a picture of the vehicle on its wheels about 200 pounds lighter.
Tonight I bought some rubber fuel line to go between the filter, pump, and tank. I got 3/8" line from Advanced auto parts. I also purchased a new hot side radiator/coolant hose. Thanks to Thunderstruck507 for the tip on using a 1982 buick riviera hose...it's darn near a perfect fit. Finally, I purchased some spectre parts for the intake. I will need to extend the wires for the MAF, but it looks like it will work. I'll post pictures (and part numbers) when I get everything together.
When I go to pick up the driveshaft I am going to have them change the end of the LS1 power steering line to the flared end that the GTO power steering box uses. I test fit it without being able to screw it in, so I am confident that everything should line up.
Tonight I bought some rubber fuel line to go between the filter, pump, and tank. I got 3/8" line from Advanced auto parts. I also purchased a new hot side radiator/coolant hose. Thanks to Thunderstruck507 for the tip on using a 1982 buick riviera hose...it's darn near a perfect fit. Finally, I purchased some spectre parts for the intake. I will need to extend the wires for the MAF, but it looks like it will work. I'll post pictures (and part numbers) when I get everything together.
When I go to pick up the driveshaft I am going to have them change the end of the LS1 power steering line to the flared end that the GTO power steering box uses. I test fit it without being able to screw it in, so I am confident that everything should line up.
Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
I made a big push to get it done for a car show last Friday, but failed. I can hear the fuel pump prime, but the plugs are bone dry, so i know that the injectors are not firing. I am going to check my wiring tomorrow.
Also, my fuel pump relay is cycling on and off very quickly after I try to crank the car. Anyone have an idea?
Also, my fuel pump relay is cycling on and off very quickly after I try to crank the car. Anyone have an idea?
On The Tree
Joined: Aug 2008
Posts: 109
Likes: 12
From: Memphis, Tennessee
Starting Issues When my son and I got our LQ9 engine running in a 66 GTO we had similar issues. To troubleshoot the problems, we used a small spray bottle and (with the throttle plate open) shot a few mists of gasoline in the throttle body. When we cranked the car over, it would immediately start. We had a fuel gage attached to the rail, and could verify we had proper pressure. I then attached a test diode to one of the injector plugs and verified that the computer was firing the injector. We then pulled the injector rails and installed an injector rail from another engine I had. The car started right up. After Seafoaming the injectors, they now work fine.
In summery, verify fuel pressure, verify injector pulse. If both are present, probably stuck injectors. This can be verified by introducing gasoline into the throttle body and then cranking the engine. If the car starts, the injectors are most likely the problem.
Hope this helps.
In summery, verify fuel pressure, verify injector pulse. If both are present, probably stuck injectors. This can be verified by introducing gasoline into the throttle body and then cranking the engine. If the car starts, the injectors are most likely the problem.
Hope this helps.
Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
I got the car to fire the other day, but I basically hot-wired it to see if the injectors would work.
I am still trying to get things working properly. I found that some of the old wiring wasn't quite what it should have been, so I played with that for awhile. My latest issue, though, is something is shorting out through the ECU ground. I think it might be bad cooling fan relays since they take 12v straight from the battery and ground through the ECU.
Everyone's help so far has been great, so if you have anymore please send it my way.
I am still trying to get things working properly. I found that some of the old wiring wasn't quite what it should have been, so I played with that for awhile. My latest issue, though, is something is shorting out through the ECU ground. I think it might be bad cooling fan relays since they take 12v straight from the battery and ground through the ECU.
Everyone's help so far has been great, so if you have anymore please send it my way.
Thread Starter
On The Tree
Joined: Jul 2009
Posts: 122
Likes: 1
From: Richmond, VA
I got the car to run finally.
The reason why the starter was not going was because I didn't have a good connection between the frame and the block. After I got that fixed the starter was turning again.
The other problem I was having was that IGN2 was wired to the battery for some reason. This was a combination of my fault and the previous owner. IGN and IGN2 should go to one wire under the hood, but for some reason they do not on my car. The simple solution was to jump the pins on the back of the key switch and unhook the IGN2 wire under the hood.
Now I just need to re-tuck all of the wires that I pulled out while I was trying to figure out why the starter would not turn. I'll start posting pictures of everything soon.
The reason why the starter was not going was because I didn't have a good connection between the frame and the block. After I got that fixed the starter was turning again.
The other problem I was having was that IGN2 was wired to the battery for some reason. This was a combination of my fault and the previous owner. IGN and IGN2 should go to one wire under the hood, but for some reason they do not on my car. The simple solution was to jump the pins on the back of the key switch and unhook the IGN2 wire under the hood.
Now I just need to re-tuck all of the wires that I pulled out while I was trying to figure out why the starter would not turn. I'll start posting pictures of everything soon.
Congrats on getting it running. All that hard work has paid off. It's a GREAT feeling (& a relief) to hear it come to life isn't it? I know it's a huge step and will give you the incentive to get everything else done. Good Luck with all the rest...