6.0L LSX/T56 swap in 1991 Z28 convertible *Test Fire 11/21*
LTX and LSXPutting LT1's, LS1's, and their variants into Third Gens is becoming more popular. This board is for those who are doing and have done the swaps so they can discuss all of their technical aspects, including repairs, swap info, and performance upgrades.
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And IIRC, no aftermarket piston uses the .940" (or .960"?) wrist pin so new rods were in order anyways.
aftermarket 4.03 bore pistons are available for the stock rod. my buddy has a set in his 370 utilizing the factory crank/rods..
you're definately doing this right and covering all of your bases. this motor will last a LONG time at your anticipated power level. i'd guess you'll get bored of it long before it gives up. great thread.
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you're definately doing this right and covering all of your bases. this motor will last a LONG time at your anticipated power level. i'd guess you'll get bored of it long before it gives up. great thread.
That was the idea behind all the parts I threw at it. however, I would argue that I'll never get tired of driving her, considering she is lucky to get driven MAYBE 2,500 miles per year now that I have a truck for a daily driver and she is on a classic car insurance policy. I do have a few ideas for backups in case I get too comfortable with the new power though. One involves a decent amount of juice, and another would be a low boost s/c of some sort, just not sure how the cam that I chose would perform with something like that. Either way, I am fine for now with almost tripling the horsepower and torque numbers from the stock motor.
Oh and thanks to davemc, I now have another wiring harness to cut up. I just got it today in the mail, it's from a '91 RS. So I have some more things to dabble with while looking for a transmission. Also, I'm still waiting on this group purchase to go thru for the tubular k-member, and as soon as I can get a good write-up of where to cut the hole in the battery tray, I will make a hole for the 4th gen coolant bottle and then repaint the engine bay. I've still got a little paint left over from painting a metallic blue '90 IROC-Z a few years ago.
Today I did some small stuff to get it even more ready for paint. I took off the EVAP line all the way back to the tank, but I still need to cap it off with a small filter or breather. I also used a bunch of Simple Green and a power sprayer to clean out the engine bay, and I cut the hole in the battery tray for the 4th gen coolant reservoir. The hole is a little bigger than it needs to be, but it does the trick. Upon further inspection of the reservoir I bought, it has a huge crack in the top of it so I need to get a new one before I put it in. The picture is just to show the fitment, it wasn't bolted down or anything.
Well here's what I purchased today, and at a real bargain I might add. It's (obviously) a T56 from an LS1 fbody, Hurst shifter ( ), with all the hydrolics, and a new clutch and aluminum flywheel (Spec 3 or 4? With Spec flywheel... 100 miles on clutch/flywheels. It's a 6 puck clutch, so I'm thinking it's a stage 4 and not a stage 3, some input here would be beneficial). Anyways, picked it up today for $1,200.
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
That's awesome buddy! I don't think you'll be disappointed going with the T-56 now. I'm in the process of shopping for a T-56 and $1200 with the bellhousing and clutch is a pretty good deal. I hope i'll be able to find one for that price.
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
I made some more progress yesterday and today. I taped off most of the engine bay and put primer down on parts that had started to surface rust. I sprayed some blue in the bay, but ran out before I got it good and covered. So on Tuesday I'm going to have to buy another can of paint so I can finish it and then put clear coat over everything. I also need to take a rag and some thinner to the brake lines and booster as well as the fuel lines. It got way too complicated taping them off, and I really felt too lazy to remove them.
I also started working on the inside of the car this afternoon. I got the seats and the top of the center console pulled out so I can cut the hole for the Hurst shifter. For those of you that swapped to T56's, do you have any pictures of how big of a hole you cut? Would it be good enough just to make a hole within the area of the 4 bolt holes for the automatic shifter? And is there any more modifications needed for the T56 swap as far as the center console is concerned?
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
Most of those questions are answered in ghetoocruiser's swap threads
Cool way ive seen for accurate and tight shifter hole cutting was to mock the tranny up under the car and mark the 4 corners of the to-be hole with a sharpie. Drill a hole at each mark and use a cutoff wheel to connect them
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
Quote:
Originally Posted by BlueZee28
I also need to take a rag and some thinner to the brake lines and booster as well as the fuel lines. It got way too complicated taping them off, and I really felt too lazy to remove them.
Dude, you're working too hard - when it comes to masking off brake lines & the like under-hood, aluminum foil is your friend!! (Saved me a LOT of time when I did my car...)
Quote:
Originally Posted by BlueZee28
Would it be good enough just to make a hole within the area of the 4 bolt holes for the automatic shifter?
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
Just a little bit of progress this afternoon, finished the paint in the engine bay with the clear coat today. And take a look at all the spider webs behind the wheels! Tomorrow afternoon when I get off work I'm going to work on takin the a-arms off so I can get the k-member out so that when my tubular piece comes in it will be ready to install.
Question for those who have the tubular k-members: Since the power steering lines mount on the stock k-member and run out towards the passenger side just to come back to the gear box, what did you do with the lines when you put the new k-member in? Did you zip tie them to the middle of the tubular piece or what?
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
Quote:
Originally Posted by BlueZee28
Question for those who have the tubular k-members: Since the power steering lines mount on the stock k-member and run out towards the passenger side just to come back to the gear box, what did you do with the lines when you put the new k-member in? Did you zip tie them to the middle of the tubular piece or what?
The power steering lines don't mount to them K-member, IIRC the only lines you have to worry about are the brake lines and the spohn k-member comes with tabs and bolts to attach the brake lines.
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
Quote:
Originally Posted by dynodanmanda79
The power steering lines don't mount to them K-member, IIRC the only lines you have to worry about are the brake lines and the spohn k-member comes with tabs and bolts to attach the brake lines.
Oh yea I think you're right. Well that's good to know about the tabs. I guess I'll know for sure when it gets here. I ordered it on September 1st but the vendor I bought it from didn't ship it out until the 10th, so I'm hoping it's here by Tuesday or Wednesday.
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
Another update: The new tubular Spohn k-member is in, along with the Spohn LSX motor mount brackets. Hopefully everything is positioned straight enough to where the motor will go in easily
Question for those with the tubular k-members: How did you run the brake lines? Do they look like mine, where they go across the k-member way out in the open, or did you find a way to tuck them in closer to the middle portion of the k-member?
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
Well they are mounted to the new k-member by the stock tabs. Spohn drilled 4 holes in their k-member so you can mount the line to it, the brake lines just don't tuck down like they do on a stock k-member.
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
If I were you, Id go tot eh parts store and get a roll of brake line and bend up a new line that either goes along the firewall base or closer to the K-member
That would eliminate any 'hanging loose' or possible snags when dropping the engine in
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
Nick, Id bend up soem new lines to get it close to the K. Atleast get them close and zip tie or somehow fasten them to the frame. Last thing you want to worry about is soemthing severing your brake lines.
As for power steering, what are you going to use? I did a braided setup. Used Russell adapters and teflon line to make mine. It tucked way away from the pulley, and looked badass to boot.
Ive read about the LS1's overheating their pumps during track time, like road course, or something along those lines, so i actually had fit a cooler into my P/S.
Btw, im still down for comin out to help you if you want! Ive got an itch to build a thirdgen again. Seeing my iroc stuffed in the corner of my shop is hurting my feelings haha.
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
Quote:
Originally Posted by SheldonZ28
Nick, Id bend up soem new lines to get it close to the K. Atleast get them close and zip tie or somehow fasten them to the frame. Last thing you want to worry about is soemthing severing your brake lines.
As for power steering, what are you going to use? I did a braided setup. Used Russell adapters and teflon line to make mine. It tucked way away from the pulley, and looked badass to boot.
Ive read about the LS1's overheating their pumps during track time, like road course, or something along those lines, so i actually had fit a cooler into my P/S.
Btw, im still down for comin out to help you if you want! Ive got an itch to build a thirdgen again. Seeing my iroc stuffed in the corner of my shop is hurting my feelings haha.
I think I'm going to try to see how far I can un-wind the stock brake lines and see how far they go. If it's not enough I'll buy longer lines and just do it that way.
And yea, I'd still be up for you helping out. I sent the wiring harness to a TGO member to have it modified, so I think I will be covered in the wiring department, except for when it comes time to actually splice the 3rd gen and LS1 harnesses together...
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
really nice post there! love your car she is a beauty, cant wait to see it finished,can you tell me if i can get my 5 speed to mount to a ls1 or 5.3 lm7, i would like to keep my t-55 but i dont know if i can get a adapter to make it work, do you know if there is anything i can do.thanks
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
Quote:
Originally Posted by camarozz383
really nice post there! love your car she is a beauty, cant wait to see it finished,can you tell me if i can get my 5 speed to mount to a ls1 or 5.3 lm7, i would like to keep my t-55 but i dont know if i can get a adapter to make it work, do you know if there is anything i can do.thanks
Yea there is a crank spacer you can buy that lets you bolt up SBC style transmissions to the LS1. I can't remember where people buy them from, Jegs might carry it? I'm sure someone here can chime in and help you out.
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
I went ahead and ordered one of those nose covers from a non-TPI Camaro that covers the hole where the TPI dual snorkel intake would be under the hood. I'm going to end up doing a cold air intake somewhat like an LT1 car and use the nose cover to cover the hole and also so I can cut a hole in the cover for the cap on the windshield washer reservoir.
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
I did some more piddling around with it today. I intended to start undercoating the car with the can of POR-15 I bought, but because it rained real hard today there was still a lot of moisture in the air and I was afraid it might hinder the undercoating's bond with the underside of the car. I ended up just cleaning up the transmission tunnel with Simple Green and some rags to get it ready for the POR-15. I think what I'm going to do is just concentrate on the transmission tunnel and then undercoat the rest of the car once it's running and I can take it to my friend's shop and use his lift. It would be pretty uncomfortable trying to undercoat an entire car while it is sitting 2 ft above the floor on jack stands.
Anyways, I was really pleased with how clean the under side of the car was under all the road grime. The trans tunnel looks brand new! Keep in mind this car has 103,xxx miles on it, and has been driven in rain and snow. Even with that considered, the frame and floor panels look awesome, the only surface rust on the bottom of the car is where the sub frame connectors were welded on.
Then after working on that for a little while and getting sick of laying on my back, I started working on the 4th gen windshield washer reservoir. I talked to my friend Aaron who posts here, you all know him as the guy that made all the tech articles on team3rdgen.com, well he was showing me the way he mounted his reservoir so he didn't have to bend up the hood latch mount. He used two short pieces of fuel line as spacers between the reservoir and the frame, and put a bolt through them to keep the reservoir off the frame about an inch. Otherwise, the reservoir hits the hood latch mount down behind the bumper. You'll see where my finger is the gap between the frame and the reservoir where I'm going to drill holes and use some fuel line as spacers to do this. As far as fitment, it mounts up great and is really snug down behind the front bumper. Now all I need to do is get a longer piece of rubber hosing to run to the windshield wipers.
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
More of the reservoir install (you can't see it from my custom grill because I mounted it so high on the frame. I even got to keep the plastic "funnel" that directs air from the grill area to the radiator:
I also got around to re-running the brake line to the passenger side front caliper. All I did was un-wind some of the line and ran it down closer to the center bar on the k-member and fed it over the a-arm mount on the other side. I didn't have to end up buying a new brake line, just used a single zip tie in the middle and then used the holes that Spohn drills in the k-member to mount it on the ends. It's not really pretty but it does the job:
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
Sorry for the multiple posts, the 5 image rule owns me.
I also got around to taking the rest of the center console out. What a mess... Does anyone know if any of the wiring from the auto shifter is used with the T56 swap, such as anything related the Neutral or Reverse? The parts in question are the big metal AK47 banana clip looking thing and this box at the back of the console area:
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
The black box in your last post is for the air bag system. Since I took the airbag out of my 91 I just completely removed that box. It would have gotten in the way of my 4th gen console anyway like it did in my 94. The wiring going to your AK47 banana mag lookin thing is VERY important. There are a couple wires there that need to be connected in order for the car to start. I believe a couple also need to go to the brake lights and the hatch release (not sure how yours works since its a vert).
BTW, I am glad someone else is going with the lt1 cai idea. I hope it works out well for you!
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
Actually all those wires that go to the banana clip have other connectors and switches in a T56 setup.
the reverse switch and neutral position is on the T56 Transmission itself. The Clutch engage switch is on the pedal.
You can remove that whole circut including all associated connectors and switches......but you would need the corresponding T56 connectors and switches.
You would need to bring some of those signals back to the console for t he hatch safety etc.
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
Quote:
Originally Posted by screeminchicken
Actually all those wires that go to the banana clip have other connectors and switches in a T56 setup.
the reverse switch and neutral position is on the T56 Transmission itself. The Clutch engage switch is on the pedal.
You can remove that whole circut including all associated connectors and switches......but you would need the corresponding T56 connectors and switches.
You would need to bring some of those signals back to the console for t he hatch safety etc.
Where is the neutral position sensor on the transmission? The only 3 connectors on my transmission are for CAGS, reverse lockout and for the reverse lights.
If I remember from doing my last t56 swap, 2 of the wires in the banana clip go to the clutch IF you want to have the clutch switch work like stock. Otherwise they need to be connected in order for the car to start.
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
Top pair will go to the clutch switch
Middle pair to the reverse light pigtail
Bottom pair are P/N
Refer to the T56 swap article I linked in the harness prep thread. He has multiple pics showing where each wire goes except the P/N wires since he was carbed
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
Quote:
Originally Posted by Pocket
Top pair will go to the clutch switch
Middle pair to the reverse light pigtail
Bottom pair are P/N
Refer to the T56 swap article I linked in the harness prep thread. He has multiple pics showing where each wire goes except the P/N wires since he was carbed
Somehow I missed that thread the first time around. I got a chance to glance over it and it sounds like it will be very helpful when I get around to cutting the hole and re-doing the wiring for the T56.
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
Today I got a huge boost of confidence. I just realized that the brake and clutch pedal assembly that I got for free a few months ago came off an LS1 car, so the transmission swap just got a little easier and less expensive. Now I don't have to worry about finding a 4th gen clutch pedal to take the master cylinder peg off of and welding it onto a 3rd gen pedal. I'm currently working on mounting the new pedals in the car right now and am trying to figure out the easiest way to cut the hole for the master. I'm trying to find someone around my area to bum a hole saw off of because the only kind I have is for wood. But nonetheless, I am extremely happy and am ready to get this thing rolling.
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
Ok, it seems as though I've run into some complications with hanging the new pedals.
For one thing, the top bolt hole (there are four holes for the brake master cylinder studs, and then a fifth hole at the top of the pedal assembly) won't seem to line up with the hole in the car. I've loosened all the nuts on the brake master studs and tried wiggling the pedals around trying to get that fifth hole to line up and I wasn't having any luck. Any tips?
Also, the two sensors on the brake pedal that screw into the pedal itself, those are a royal pain in the butt. I was having a hard time adjusting these because if I'm correct, you have to set them to were the ends of them are compressed when you're not touching the brakes, and when you hit the brake pedal it releases the end in the sensor to trip the brake lights. Well, I can't seem to get them to sit in far enough to touch the brakes when the brakes aren't being used. One possibility I thought of was that perhaps these sensors are different between 3rd and 4th gens? Since I have 4th gen pedals, do I need to get 4th gen sensors for the brake pedal?
Also, what is the sensor that screws into the clutch pedal? It looks similar to the two sensors on the brake pedal, but it's for the clutch? Is something from the wiring harness going to have to plug in there?
Re: 6.0L LSX/T56 (YES!) swap in 1991 Z28 convertible
Quote:
Originally Posted by Pocket
The clutch should have two things on it
Clutch switch which interrupts the starter and another that interrupts cruise
Does anyone know if it's possible to get those switches new?? I haven't been able to find 'em locally, & I really HATE the thought of trying to use junkyard pieces from cars that probably have triple the mileage that my car does...