GTM #534 Build Log

[ohmygosuness]

Hi everyone,

My name is Fei. I'm 33 and I live in Texas. I'm a very inexperienced builder. A lot people said the GTM kit isn't beginner friendly at all. But I enjoy being hands-on and I love performance cars, so I said **** it and pulled the trigger. I took delivery of GTM#534 around February 2022 (I made a post about it last year saying the delivery driver told me it was the last one). I've been working on it on and off, mostly during the winter times when my garage feels more comfortable than an oven.

I've been reading you guys' post pretty much word-for-word for the past 2-3 years. So, I decided it would be a good idea to post here about my progress. Everything I'm posting will be my first time doing it. Also, to make the "beginner experience" worse, I got a C6 donor instead of a C5. I feel like I possibly shot myself in the foot with this decision but I'm pretty optimistic that I'll eventually make it work (with a ton of research/modifications, of course).

I've seen a lot of yall's build and they're pretty amazing. If the things I post looks like I have no idea what the hell I'm doing, then you're probably right. So, please feel free to offer some pointers. I'll try to be as detailed as I can with my posts/replies. I'm currently at work. I'll start posting later when I'm at home. Thanks!

Fei

[VRaptor SpeedWorks, LLC]

Welcome aboard! Looking forward to seeing your progress...

[ohmygosuness]

Hi Shane. Thanks!
I believe I still owe you some dimensions for the location of the shifter (if I remember correctly). I know it's been a while but it's always in the back of my head.

[ohmygosuness]

IMG_20220208_181349_01[1].jpg
I've worked on the build very little since delivery, but a lot more last few months. The only things I have on it so far is the suspension, C6 steering column, 3 reservoirs.
C6 front suspension works on the GTM. Rear upper control arms don't work.
C6 steering column needs a little adjustment. I grinded off a lot of material for it to fit.
steering3.jpg
steering2.jpg
steering1.jpg
I have the c6 corvette sitting next to the GTM. Taking it apart piece by piece as I put them into the GTM. Engine will be a stock ls2 with 65k miles.
IMG_20221211_012016_965[1].jpg
Cleaned every piston from carbon build-up. Got all new gaskets/piston rings, gapped all the piston rings, honed each cylinder, etc
clean pistons.jpg
dirty pistons.jpg
honed cylinders.jpg

While uploading these pictures, I came to a realization that I've spent more time prepping the engine than actually installing parts onto the GTM. But I'm at the final stages of putting the engine together. Just waiting for the paint to dry on the cylinder heads before re-assembling the engine.

[VRaptor SpeedWorks, LLC]

Yes.....I was looking thru my orders spreadsheet the other day and saw that I still showed that I owe you that plate. Whenever you're ready, just let me know.

That C6 steering column sure looks like a whole different beast than the C5!

[Shoeless]

Looking forward to the posts!! We'll gladly let you know if something is wrong LOL . On a serious note, the recommendations and pointers from the group are pretty solid, so feel free to ask away.

[ohmygosuness]

Looking forward to the posts!! We'll gladly let you know if something is wrong LOL . On a serious note, the recommendations and pointers from the group are pretty solid, so feel free to ask away.

Hi shoeless. I like what you did with your build! I've been following it carefully as I'm building mine. Mine's just not as detailed

[ohmygosuness]

Here's another thing from the C6 that don't fit as good as C5 for the GTM - the Gen IV LS valley cover. I grinded off that big pipe sticking above the valley cover to clear the throttle body. Still trying to figure out how I should cap off that hole. I'm wondering if a bolt will do the trick?
valley cover.jpg
Here is the part I got to relocate the oil pressure sender. Anyone has a recommendation on which sensor I should get?
oil presser sender.jpg

[VRaptor SpeedWorks, LLC]

http://vraptorspeedworks.com/ls-engi...-modification/

As for the oil pressure sender, you need to use the one that comes with the oil pressure gauge in the kit. If that block you have above the filter is to relocate the OEM sensor, it probably won't work for the gauge sender as the gauge sender is 1/8" NPT and the OEM sender is....I believe a straight metric thread with a crush washer? For the gauge sender, I normally take the OEM cast aluminum bypass piece and drill and tap it to 1/8" NPT.....

[ohmygosuness]

http://vraptorspeedworks.com/ls-engi...-modification/

As for the oil pressure sender, you need to use the one that comes with the oil pressure gauge in the kit. If that block you have above the filter is to relocate the OEM sensor, it probably won't work for the gauge sender as the gauge sender is 1/8" NPT and the OEM sender is....I believe a straight metric thread with a crush washer? For the gauge sender, I normally take the OEM cast aluminum bypass piece and drill and tap it to 1/8" NPT.....

Drilling through the OEM cast aluminum piece is a good idea. I think I should have done that instead...

As for the relocator I bought, I do believe they sell an adaptor to 1/8" NPT. But I'm not sure if the transducer will be able to mount directly above it after using the adaptor. I think i may have to get one that's angled.

As for the hole on the valley cover, would it work if I just fill it up with some metal filler/epoxy?

[VRaptor SpeedWorks, LLC]

As for the hole on the valley cover, would it work if I just fill it up with some metal filler/epoxy?

As long as the epoxy you use is completely unaffected by oil and heat and you create something inside the hole for it to hold to....like get a dremel down in the hole and grind some grooves into the aluminum so that the epoxy is not just a smooth sided plug that could pop out under pressure......that might work?

[Ajzride]

As for the hole on the valley cover, would it work if I just fill it up with some metal filler/epoxy?

I wouldn't risk it. Tap the hole and fill it with a screw in plug.

[crash]

I wouldn't risk it. Tap the hole and fill it with a screw in plug.

THIS.

If you want to make it permanent use epoxy on the threads.

Are you sure you have to remove the sender cast piece? I seem to recall I did this the first time I did a build and flipped the intake around. Then on a second engine I recall just trimming the intake manifold to clear the casting and using a plug in it. Yes you still have to relocate the sensor, but no cutting, tapping/welding of the valley cover is needed...IIRC. I haven't done a flipped intake in a long time though.

There are also available valley covers with the sensor blocked off...

https://www.summitracing.com/parts/icb-551646

For $42 it saves a bit of work and looks nice and clean.

[VRaptor SpeedWorks, LLC]

The oil pressure boss on the LS3 is really tall......no way to avoid cutting it off. You can see in the top photo here just how far it holds the flipped intake up off the heads:

http://vraptorspeedworks.com/ls-engi...-modification/

Even with it cut down so it only sticks up an 1/8" or 3/16", you may still need to trim a bit of the plastic webbing from the bottom of the intake to clear it.

[ohmygosuness]

Shane, Ajzride, crash, thanks for the response. After reading your inputs, I believe I'm going with thread tap then plug option. Still waiting for the plug to arrive (hope I ordered the right size).

Shane, I do have some epoxy for exhaust repair, so it is heat resistant. I may end up putting epoxy on the threaded plug like crash suggested, to make it more permanent (if that's what he meant). I'll definitely post pics when it's done.

Question about power steering pump on the engine: do we use it on the gtm? If not, do I need a shorter belt?

[beeman]

I am aware of an early build that used the C5 power steering rack, but 99% use the manual rack from FFR.

[ohmygosuness]

I am aware of an early build that used the C5 power steering rack, but 99% use the manual rack from FFR.

Hi Beeman. Yes, I do have the manual rack from FFR installed. So, I don't think there's a need for the power steering pump. I was wondering if I need an aftermarket belt or a power steering delete bracket to make this work.

[beeman]

Lots of ways to run the belts depending on your accessory locations, mainly the alternator. Where are you running your alternator?

[VRaptor SpeedWorks, LLC]

All of the belt/relocation brackets should be included with the GTM kit to mount the alternator and install the donor belt tensioner. The other options are to use the Cadillac CTS-V alternator mount instead of the FFR mount since the FFR mount is not great. I also offer a belt tensioner kit that replaces the FFR bracket....which, once again, isn't great but can work.

[rolfer]

I have Shane's belt tensioner kit and can say it works very well. I would recommend it!

[Shoeless]

Hands down the best setup is the CTS-V Alternator and bracket with Shane's belt tensioner. Especially if you are going with a bit higher HP.

Make sure you get the right alternator as Cadillac changed over mid year and the old one needs a PWM signal to turn on and that's the one I got as I can control the output voltage with my ECU. There are a few large threads on the other forum with details you can read up on.

[ohmygosuness]

All of the belt/relocation brackets should be included with the GTM kit to mount the alternator and install the donor belt tensioner. The other options are to use the Cadillac CTS-V alternator mount instead of the FFR mount since the FFR mount is not great. I also offer a belt tensioner kit that replaces the FFR bracket....which, once again, isn't great but can work.

Sometimes I'm just waiting for orders to come in and I'll be day dreaming about how am I going to put everything together on the engine. I may be thinking way ahead of myself. Thanks for letting me know that they provide a bracket in the kit to adjust the belt.

I just noticed I'll need a C5 AC bracket as well as a C5 AC compressor. I just have them ordered, currently waiting for them to come in before I start thinking about dropping in.

What's wrong with the FFR alternator relocation bracket?

[ohmygosuness]

Hands down the best setup is the CTS-V Alternator and bracket with Shane's belt tensioner. Especially if you are going with a bit higher HP.

Make sure you get the right alternator as Cadillac changed over mid year and the old one needs a PWM signal to turn on and that's the one I got as I can control the output voltage with my ECU. There are a few large threads on the other forum with details you can read up on.

I'm assuming the main reason to use CTS-V alternator is for the voltage output adjustment?

Currently the engine is a stock LS2, should be making around 400 HP. I do have plans to make a bit more power, with something along the lines of AWD. I'll definitely look into the CTS-V. Still waiting for the C5 AC compressor/bracket to come in, so I can install it before dropping the engine in.

[Shoeless]

The main reason for using the CTS-V alternator and bracket is the rigidity. When compared to what the kit wants you to use, it’s far superior. Pair that with Shane’s Belt Tensioner, again superior rigidity, you have a solid setup.

Unless you are going with an aftermarket ECU and doing your own engine harness, make sure to get the one that is NOT PWM Controlled.

[beeman]

Main reason is that the FFR supplied bracket /pulley is not rigid enough and prone to making noise, and I believe jumping belts.

[ohmygosuness]

Been working on the hole sticking out on the valley cover. Got a 3/8" NPT plug then tapped the oil pressure sensor hole with 5/8" threads. Screwed in the plug up-side-down so the flat end is flush with the top of the cover. The plug width (thread-to-thread) is slightly wider than 5/8", something like 21/32. This allowed me to torque the plug into the thread really tight. I was going to add epoxy to the thread to make it more permanent, but seems unnecessary. Although, I could fill the underside of the cover with epoxy just so it could be flat.
valley plug.jpg
plugged valley bottom.jpg
plugged valley cover top.jpg

[ohmygosuness]

Thanks you guys for the heads up. I'll definitely be looking into CTS-V alternator/bracket.

[crash]

Been working on the hole sticking out on the valley cover. Got a 3/8" NPT plug then tapped the oil pressure sensor hole with 5/8" threads. Screwed in the plug up-side-down so the flat end is flush with the top of the cover. The plug width (thread-to-thread) is slightly wider than 5/8", something like 21/32. This allowed me to torque the plug into the thread really tight. I was going to add epoxy to the thread to make it more permanent, but seems unnecessary. Although, I could fill the underside of the cover with epoxy just so it could be flat.
valley plug.jpg
plugged valley bottom.jpg
plugged valley cover top.jpg

DO NOT fill the underside with epoxy. You need to be very careful with anything that is in the oil system on the engine. ANY contamination, like little bits of epoxy that might break off, can cause catastrophic engine failure. Avoid putting anything into the engine oil system after the filter that could even possibly be an issue. If the plug is tight enough I might recommend a bit of Teflon tape to make sure there are no leaks, but again, be double sure that you clean any excess off the threads before installing the cover. This is critical.

[ohmygosuness]

DO NOT fill the underside with epoxy. You need to be very careful with anything that is in the oil system on the engine. ANY contamination, like little bits of epoxy that might break off, can cause catastrophic engine failure. Avoid putting anything into the engine oil system after the filter that could even possibly be an issue. If the plug is tight enough I might recommend a bit of Teflon tape to make sure there are no leaks, but again, be double sure that you clean any excess off the threads before installing the cover. This is critical.

Noted. No epoxy. I do have Teflon tape, I'll probably try that instead. Thanks.

Man, am I glad I posted it on here before trying something stupid

[ohmygosuness]

Been waiting for some stuff to come in, like the AC bracket. Can someone confirm if I got the right one?
ac bracket1.jpg
ac bracket2.jpg

Also, this water pump came with the engine. Would it work for the GTM or do I need one from LS1?
water pump front.jpg
water pump back.jpg

[VRaptor SpeedWorks, LLC]

Not positive on the AC bracket, but looks like it's the right one to me. There may be a boss on the bracket or the engine block that will need to be removed for that bracket to fit an LS3. Same with the the motor mount brackets.....they bolt up and appear to fit, but there is interference between additional bolt bosses on the block and the bracket that need to be ground down for a proper fit.

You will need an LS1 water pump with the large bell-shaped pulley (1999 Corvette fitment). The pump you have is a newer pump and will hit the chassis at the t-stat housing.

[Shoeless]

It may or may not need to be said, but it tripped me up, so I'll share here.

When I got my LS3, I bought the LS1 water pump as Shane mentioned above, but kept the LS3 T-Stat housing as it appeared to fit. That's a no go as I had about 1/16" clearance to the frame. You need to get an LS1 T-Stat housing as well.

[ohmygosuness]

Not positive on the AC bracket, but looks like it's the right one to me. There may be a boss on the bracket or the engine block that will need to be removed for that bracket to fit an LS3. Same with the the motor mount brackets.....they bolt up and appear to fit, but there is interference between additional bolt bosses on the block and the bracket that need to be ground down for a proper fit.

You will need an LS1 water pump with the large bell-shaped pulley (1999 Corvette fitment). The pump you have is a newer pump and will hit the chassis at the t-stat housing.

I hope this is the right AC bracket. It supposedly came from the LS1 and looks way different. It looks similar to the one in Shoeless' build log
There is a boss on the bracket that I had to tap it with M10 to fit the M10 bolts that came with the LS2 AC compressor. Maybe that's what you're talking about. But I haven't installed it yet. Will definitely let you know if I something that don't fit (fingers crossed).

Yes, you're right about the motor mounts! I had to drill a hole into each of the spacers so that little 1/4" nub sticking out below won't interfere when mounting the engine.

I got a new water pump.
water pump.jpg

[ohmygosuness]

It may or may not need to be said, but it tripped me up, so I'll share here.

When I got my LS3, I bought the LS1 water pump as Shane mentioned above, but kept the LS3 T-Stat housing as it appeared to fit. That's a no go as I had about 1/16" clearance to the frame. You need to get an LS1 T-Stat housing as well.

Thanks shoeless. Noted.

[ohmygosuness]

Here is the AC compressor with bracket.
PXL_20230309_044243511.jpgPXL_20230309_044222625.jpg

[VRaptor SpeedWorks, LLC]

That does look like the correct AC bracket.....and I don't think it will bolt up to an LS3 without grinding either the bracket or the engine block to make it fit. Same with the aluminum brackets that bolt up to the engine block that the motor mounts attach to. Where the alum brackets meet the block, you may be able to get all of the bolts started and seems like everything fits, but if you look, the bracket is not sitting up against the engine block like it should....this is on the pass side bracket.....there is a bolt boss on the engine block that sticks out and holds the bracket out away from the engine block. You will need to grind something to make it fit. I've seen this dozens of times with cars we've worked on here where the previous owner just bolts the bracket up to the block and then goes to install the engine and wonders why the motor mounts don't line up with the chassis.

[Shoeless]

I did a little blending on my motor mounts like Shane notes, an it worked perfectly.

[ohmygosuness]

I've been working on making the FFR alternator bracket stronger by welding on some gussets since you gentlemen mentioned it's a bit fragile.
alt bracket1.jpg
alt bracket2.jpg
alt bracket3.jpg
alt bracket4.jpg
I was recommended to get the bracket from CTS-V, not sure if I needed the alt from CTS-V as well. But it would ended up costing a lot more. This project only costed me $12 (replaced the aluminum bushing on the 1/2" pulley bolt to steel and fishing up some scrap metal from work for the gussets). If this bracket still gives me issues down the road, I'll go for the alt bracket from CTS-V.

PS: some of my welds look like boogers because this is my first welding project. But I made sure it had good penetration

[ohmygosuness]

I'm working on routing the brake lines. The cylinder on the left appears to be interfering with the frame after I snugged the fitting in the front. Is this suppose to happen or am i just being dumb?

Also, I know all the cylinders are the same but is there a preference as to which one to use for which (front/rear) brakes in terms of giving maybe slight advantage in the routing process?

master cylinders.jpg

[doug_porsche]

I suspect that is the MC you are using for the front brakes.
On my, and all the pictures I can find of others, the front port is for a "bleeder" and the top port is run to the calipers.

The front mc has the line coming out of the top port, going to a tee, and then to each front caliper.