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-   -   '70 Nova LSX swap LY6/TH400 (http://www.offroadfabnet.com/forums/showthread.php?t=8160)

TheBandit 09-13-2010 12:38 PM

'70 Nova LSX swap LY6/TH400
This thread will document my swap from a tired gen I small block 350 to a modern 6.0VVT LY6. This will be my first time doing this kind of a swap, so bear with me! I've had my Nova since I was fifteen. It was my first car and even though I'm now in my late twenties, married, and have a newborn son, it still holds a special place in my life.

First a few pictures. Here is a recent shot of the car. The wheels are Centerline Convo Pros with 275/60R15s out back and 225/60R15 up front.


Finishing off an old pair of tires:






Here is the old small block in all its glory. When I was in high school I did a frame off on the car. It had Edelbrock Performer RPM heads, a Comp cam (232/236 @ 050 .488/.490), and a Demon 650DP. After over a decade of hotrodding, compression was getting low, oil was blowing from every gasketed interface, and the final straw was a bent pushrod and flat lobe on the cam.


Originally I was a big drag racing fan and always pictured this car tubbed and tubed with a big block. But as I grew older, I started to appreciate other aspects of driving like stopping and turning. I became increasingly frustrated with carburation. As the engine got more and more tired, started burning oil past the rings, and eventually met it's demise, I decided rather than rebuilding the smallblock, I wanted to go a new direction entirely. After much research, I decided on a modern, fuel injected LS engine.

More specifically, I decided on an LY6. The LY6 is an iron block 6.0L that comes in the new body style Chevy/GMC pickups and vans. It has the desireable L92/LS3 cylinder heads, an iron block, and some black magic voodoo few people want to mess with: variable valve timing. Being an engineer, I can't help but appreciate the academic merits of VVT and I plan to use it, along with an aftermarket cam (yet to be selected).

I found my LY6 from Eiss Brothers Salvage in New York. It has 60k miles and I paid $1650 for the longblock. On top of that I spent another $300 on accessories (ECM, alternator, PS pump, wire harness, starter, and drive by wire pedal assembly) and $200 in freight for a total of $2150 for an accessorized engine shipped across the country. It was like Christmas when the new engine arrived last month.



Time to put the old hoist back together:


I quickly cobbled together a lifting bar using some old scrap square tubing and 1/4" plate. I was worried about damaging the intake with chain, but looking back I probably could have come up with a simple chain system that would have worked just as well.


I used four M10x1.5 100mm long studs to attach the engine stand mount. I found the studs at my local Ace hardware. Unlike bolts, they don't need to be a specific size as long as they're long enough. They are probably only grade 5 or worse, but as long as they're snug, they should be fine.


I am using a Harbor Freight 2000lb capacity stand, part number 60715 (link). This is a pretty decent and stable stand. I wouldn't trust any of their lesser capacity stands. I don't buy a lot of chinese tools, but I don't think you can get a US-made engine stand for under $500 so this will have to do. 20% off coupon plus a sale and I paid $85 out the door.


TheBandit 09-13-2010 12:45 PM

With the engine on the stand, I started by stripping the wire harness. It's completely intact and I plan to use it, so I carefully labelled the connectors I could identify with my wife's label maker.



Without the harness, it starts looking like a good ol' American V8 again


Before I did anything else, I wanted to check the condition of the engine. I did a leakdown check first and got some varying results, with leakage past some valves sometimes and sometimes not. After talking with the salvage yard about the results, they recommended I put a little tranny fluid in all the cylinders and on the valves, turn the engine over a few times, then retest. I went a little further and decided to do a compression check, which would turn the engine over plenty and give additional diagnostic info. Here's my setup for cranking the engine with the starter on the stand. I would never do this if I didn't think the stand were very stable!


With that little bit of lube, the results improved and leakage was down to nil on all cylinders with good compression above 180psi on all cylinders.

TheBandit 09-13-2010 12:58 PM

I'm not a big fan of the tall truck intake, so I dug around and found a take-off LS3 intake from a 2010 Camaro for $215 shipped. I started this thread to collect more info on what's involved in swapping from a truck intake to a car intake on this engine.


Because the car intake places the throttle body much lower, there are a few places where things interfere with the truck accessories. First is the waterpump outlet, which can interfere with the motor drive assembly on the electric throttle body as shown here. This is before snuggin the intake down.


I used a Dremel and a small cutoff wheel to remove the offending aluminum. I like cutoff wheels for trimming aluminum like this because they don't clog up dangerously the way grinding wheels do. Here it is trimmed:


The next order of business will be relocating the idler pulley which is now in the same area as the throttle body. I started by taking the pulley of it's bolt as shown:



Then I used washers for mockup to temporarily locate the idler on one of the mounting bolts for the accessory bracket. I have a new machined spacer and bolt on order that will permanently attach this for under $8. I will post the part numbers after I verify fitment.


After trimming off the accessory bracket, I think I will have the following two options for belt routing. The second option is my preference since it more closely resembles the original belt routing, it provides more wrap around the pulleys, and the tensioner is acting in the direction of the belt.



TheBandit 09-13-2010 01:05 PM

Meanwhile, after selling off a bunch of parts from the old smallblock, I finally got around to pulling it. I supported the tranny with a ratchet strap prior to pulling the engine.




Goodbye old friend!


Things under the hood just aren't as pretty as they were over a decade ago when I did a frameoff. I'll have my work cutout for me cleaning this up.


That's all for now. This is going to be a slow build, but I'll be sure to post updates as I have them.

8Ball 09-13-2010 03:09 PM

I've always liked that body style Nova the best.
Unfortunatly here in Ohio, they weren't rust free very long.
The new wheels look killer too

streetwerkz 09-13-2010 04:27 PM

looking good, if your after getting that thing to corner at speed check out www.lateral-g.net

A good source of info for g-machine, resto mod, etc

som ws9 09-13-2010 06:41 PM

Great build! I look forward to seeing progress on this. I've done a few LS swaps myself and have had a blast with these engines.

As mentioned above, the guys over on Lateral-G should be a big help doing an LS swap on a Nova and helping you get the chassis worked out as well.

gearheadmb 09-14-2010 02:28 PM

Is the bellhousing bolt pattern the same from the old engine to the new one or do you need some sort of adapter plate?

TheBandit 09-14-2010 03:22 PM

Thanks guys. It's just the beginning to a long, drawn out build!

gearheadmb - The bellhousing pattern for the LS engines is essentially the same as the gen I smallblocks. LS engines use all metric fasteners. There are some caveats for using older trannies on the LS engines, for example in my case I will need a spacer at the back of the crank to support the nose of my torque converter. I bought a TCI flexplate and spacer that have the correct patterns and spacing to mate my LY6 to the TH400. Most LS engines require the spacer, some do not.

AVTECH 09-14-2010 06:52 PM

Nice job Clint, I always enjoy reading your threads. Great naration and Pix!:bounce2:

TheBandit 09-30-2010 07:19 PM

Thanks AVTECH.

As promised, here is how I relocated the idler pulley and made the truck accessories work with the car (LS3) intake for under $10. Granted I do still need to buy a belt, but I'm also thinking about scrapping this altogether and making my own brackets from scratch. I don't like how high the alternator sits with this setup.

First off the parts. From Misumi USA (www.misumiusa.com), the spacer is PN KNCLM10-30-20 and cost $5.70. It is nickel plated steel, 10mm ID, 30MM OD and 20MM length. The bolt is PN CB10-160 and cost $2.40. It is M10x160mm length. Total $8.10.


Here you can see that the spacer is the appropriate height to position the idler in line with where it originally was


I am spoiled with a mill in my garage, so I used it to cleanly trim down the bracket. You could also do this with a vertical bandsaw or even a hacksaw.




Here is the trimmed bracket around the throttle body


And here you can see a notch I added for the vacuum port on the drivers side of the intake


Here is the ilder pulley mounted with a ratchet strap used as a mockup belt


The Misumi spacer installs here:


And this is what the finished accessory drive looks like using a ratchet strap to mockup the belt path.


Sorry about the black & white pictures. Somehow the setting got changed while I was taking pictures.

I haven't decided yet if I want to keep this setup or scrap it altogether in favor of putting the alternator on the passenger side (lower) and making my own brackets for everything.

That's all for now!

TheBandit 10-10-2010 11:27 PM

Here are a few more shots of the truck accessory drive with the car intake. I am probably going to order an a/c compressor and see where things fit before I decide what I want to do.




This weekend I decided to tackle cleaning up and painting the engine. First I needed to seal everything up to prevent water from getting in.

I removed the valve covers and removed the rocker arms. This puts all the valves in a closed position, which should help prevent any unwanted liquids from getting in.


Next I stuffed the ports with towels and used a quality (Scotch brand) duct tape to mask off all the ports and sensors.


Then I laid a tarp out in my driveway, rolled the engine out, and went to town with a few cans of engine degreaser, a scrub brush and the garden hose. These pictures were taken at various stages of cleaning.





On the last few clean & rinse cycles, I used Eagle One Mag Cleaner in a spray bottle from my local autoparts store. This is an etching cleaner that contains a few different acids. It did an incredible job of restoring the aluminum to a more uniform appearance. Once everything was degreased and thoroughly rinsed, I put a few fans out to dry things off.


TheBandit 10-10-2010 11:28 PM

Next I used some painters tape and masked off the heads, waterpump ports, and cam position sensor boss. Most of the other connectors were already masked off with duct tape from earlier. For the waterpump ports, I put tape on the old gaskets and used some bolts to hold them in place.



Finally, I laid on several coats of Duplicolor engine enamel. I used this on my old small block and it lasted 12 years and still looked good when I pulled the engine.


These pictures were taken as the paint was still drying, so it looks kinda splotchy but you get the idea.


Later this evening after rolling her back in the garage, I set the intake back on top and snapped these photos. Overall I'm pleased with how this cleaned up and I'm very happy with the painted valve cover, painted timing cover look. I wish it wasn't going to get cluttered up later with accessories, wires, etc.







That's it for today. More to come as I make progress.

roco 10-11-2010 03:47 AM

looking awesome clint, im a big fan of the novas, there a cool little car.

streetwerkz 10-11-2010 08:09 AM

much nicer, I especially like how you didn't make everything one color.

CarterKraft 10-11-2010 12:58 PM

nice cleanup work, it's all in the details you know.

As for the truck alternator up high deal, loved it when you where building it...

After seeing it mounted on that clean engine, it needs to go down BUT!!! if the a/c goes on you are running out of room. I was thinking no problem put the a/c low passenger side but second thought it might be easier to clean up the compressor if one of them has to go on top.

All in all I don't prefer high mounted accessories in muscle cars but sometimes you got to fit it all in.

TheBandit 10-11-2010 03:58 PM

Thanks guys - I appreciate the encouragement. I don't think it will be a show winner or look as nice as my old smallblock in its glory days, but I'm pleased with the results of the spit & shine.

Today I stopped by the local stealership parts counter and ordered an L99 waterpump and powersteering bracket. I'm going to try to piece together something like the L99 accessory drive, either by buying parts incrementally or fabricating parts as I need them. I'm hoping the L99 waterpump will line up with the truck crank pulley and the truck PS pump will work on the L99 mount. If those work, I'll go on to figuring out the alternator and compressor mounting.

Here is the L99 accessory drive, which you can buy as a complete setup from Pace (link) for $860.


Here are the part numbers and list prices I got from the dealer. They provided some exploded views to help ID things.

19207665 Waterpump $300
12610792 P/S pump bracket $20.70
92229662 P/S pump $156.87
12610794 P/S pump pulley $40.16
12610789 alternator bracket $49.84
12568996 alternator idler pulley $65.02
XXX tensioner (I didn't ask)
XXX belt
XXX alternator
Total list $632.59 without tensioner, alternator, belt or hardware

Based on the list prices, I think you might be able to beat the Pace price if you're willing to go to your local dealer. I asked nicely and the stealership gave me a 15% discount along with a coupon for another 15% off my next order, so for the waterpump and P/S pump bracket I paid a hair under $300 out the door with tax.

One other very important note. The parts counter guy was concerned that some of these parts could be on a long national backorder. He checked on these and said they were in inventory someplace and he was very confident they'd get here in a week. However it's very possible they could be delayed since they are such new items. I will let you know how my experience goes.

TheBandit 10-12-2010 01:18 PM

After posting this on ls1tech, a member pointed out that gmpartsdirect.com has much better pricing. I spent some time on the phone, got a better deal with my local dealer's web pricing (their site is www.gmpartsgiant.com) and augmented my order to include all the parts below. The total is close to the same as it would be with gmpartsdirect, but I can pick up the parts when they get here. The key is not paying shipping with the local dealer, even though their web prices are a bit higher and I will have to pay tax.

List / www.gmpartsgiant.com before tax

19207665 Waterpump $300 / 177.54
12610792 P/S pump bracket $20.70 / 12.14
92229662 P/S pump $156.87 / 95.78
12610794 P/S pump pulley $40.16 / 24.09
12610789 alternator bracket $49.84 / 29.89
12568996 idler pulley $65.02 / 39.70
Total $379.14 + $36.97 tax = $416.11

I'm hoping the truck balancer with line up (we'll see) and I skipped the tensioner for now because I will need to mount my a/c compressor in that area and I don't know what I'll use for a tensioner yet.

TheBandit 10-17-2010 02:24 PM

Friday I picked up everything but the p/s bracket (still waiting on that). The good news is the L99 waterpump bolts up and the pulley matches perfectly with the truck crank pulley. It even came with the gaskets. I couldn't be happier.

Here are some pictures comparing the LY6/L92 truck waterpump to the L99 Camaro waterpump. The belt contact area of the L99 waterpump pulley aligns perfectly with the truck pulley, despite the overall size of the pulley being shorter. On the backside, there is plenty of clearance for the VVT timing cover, which I assume is the same between the LY6, L92 and L99.


On the engine:


The driver's side, forward outlet should make hose routing cleaner for my Nova's driver's side inlet radiator. This may restrict belt routing options for driver's upper accessories if not using the L99 accessory configuration. I will try bolting the truck accessories up to see if they would work with alternate belt routing, even though at this point I don't plan to use them.


On the passenger side, you can see the bosses for mounting the L99 tensioner are thicker and stick out further, so the LY6 tensioner will not line up. If you were swapping straight across, you would want to get the L99 tensioner.



The bad news is the alternator bracket is designed a little differently from the 4th gen f-body setup and it pushes the alternator out further from the block at the top mounting bolt. That is likely to be a problem in the tight space between the engine and subframe on my Nova. I may need to use a spaced-out 4th gen f-body bracket for things to fit, but I wont know until the engine is in the car.

feva4u 10-17-2010 05:17 PM

Love the tech/car. Getting ready to put a LQ4 into a 70 chevelle SS so your posts have been helping quite a bit. Keep up the details and good work :eyemouth:

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