TURBO L6 BUILD

Now I wont say this idea was original, there are many people before me who have turbocharged their Chevy Inline Sixes, this is just my log of how I did mine. I was not on a quest for crazy horsepower but for a decent running L6 with a little boost just to make things interesting. A lot of people ask me "What's your HP/ET Goal?" honestly I don't know and really don't care, I think i just wanted to see if I could do it. So sit back and relax I will try to give as much detail as possible. For anyone interested in hot rodding or maintaining your Inline Six please visit WWW.INLINERS.ORG and join there bulletin board. There are a lot of knowledgeable people there to help you out. And so Begins my Turbocharged Quest.

This is where it all started, I had a 72 Nova with a busted V8 and decided to swap back in a Inline 6 just for the fun of it. At the time I had no plans to Turbo charge the car. I picked up what turned out to be a 230ci L6 from a 70ish Nova. It came with a 3spd Saginaw attached. The trans came off first since I was going to reuse my TH-200R4 Overdrive that was already in my Nova. Although the motor has sat for a while it turned over freely and was overall in decent shape.

After removing all the accessories and giving the motor a through degreasing I knew I had to paint it. Now I could have gone with the original "Chevy Orange" or a simple Black, even a nice Blue to match the car. But when at the part store I noticed a color called "GM Alpine Green" it really caught my eye. I thought why not it should it least make the motor stand out. So I gave it a quick once over, hit the pulleys with a flat black and here's what we ended up with.

Once painted I flipped it over and inspected the bearings. They showed normal wear and indicated no immediate problems, so I purchased a new oil pump, and a full gasket kit. We replaced the front and rear main seals, all the external gaskets and installed a new water pump. After which I installed my 100amp 1-wire alternator and hit the valve cover with a fresh coat of flat black.

   

At this point I had a decision to make, the stock balancer was wore out and they are known for the rubber seal going bad and loosing time or as I found out years ago, tossing the pulley off the balancer. Either I replaced it with a stock one or a 6.5in SBC balancer. Luckily a friend from the Nova Listserve runs a machine shop and was able to modify the SBC balancer for me. Now you can run these with no modification but it will push your crank pulley out past the stock location, requiring you to shim the rest of your pulleys out, or you can have a Belt Grove milled into the balancer and the snout cut down ever so slightly and it will all line up perfectly. Now the advantage to the SBC balancer is that they will not come apart as easily as the stock ones and they will handle vibration much better due to their larger size. Also you can see I had to remark the TDC mark on the balancer also.

   

So essentially the long block is done, now sure I could have done a full rebuild, new bearings and rings but I saw no need to. Next is onto the Intake and Exhaust, now around this time I got the idea that I was going to Turbo charge this car, at first it was looking to be quite the undertaking but when I came across a deal I could not pass up on a turbo it was a done deal. Well talk more about the turbo later on. I knew that the stock 1bbl just wouldn't cut it, but being that this is a stock motor my 750DP Holley would be just too much. I tossed around ideas of running a Holley 5200 Progressive 2bbl but ended up on getting just your run of the mill Holley 2bbl of the 500cfm variety. Once again a used piece and a deal from one of my fellow Nova Listserve members. Then by chance on Craigslist I came across a guy locally selling an Offenhauser 4bbl intake. This was great but by design the intake mounts the carburetor transverse and this would have required much work with trying to hook up a TV cable for the overdrive transmission. So with some trail and error and a piece of 1/4in steel plate I made the adapter you see below. A very simple design that works out great.

       

This was it for the Inline, it was now time to actually install it. I located a set of 6 cylinder frame mounts and went to work. We had alredy pulled the V-8 out so it was as simple and installing the new frame mounts, and dropping the motor in. By this point I was collecting parts for my turbocharger setup so before the motor went in I installed a AN drain fitting into the oil pan. Using a -6an bulkhead fitting we drilled a hole tightened the nut down and installed a dab of JB Weld to make sure it didnt come loose and until that day came to use it we capped it off. The motor went in easy and lined right up, ive dont this many times so it was a fairly quick job just bolt everything in and tighten everything down. Once it was in we also opted to remove the points ignition and install a Petronix Ignitor. For the same price we could have refurbished a used HEI, but I like the fact that you get a great spark and good reliability with this kit while looking stock. This also compliments the MSD Blaster 2 coil and MSD Digital 6 pieces that were alredy on the car.

       

Here is where we ran into our first problem. I wanted to get the car running N/A first to make sure it was in working order. I hooked up the starter and used a cylinder pressure tester to see how good of shape the motor was in. We found good pressure on all cylinders except for #1 which showed 30psi. This was diagnosed as a bad intake valve by using a leakdown tester. So off the head came and low and behold it had a few bad intake valves and all the exhaust valves were sunk into the head. I took it to the local machine shop and had them give it a once over. All new valves, seals, and guides as well as new intake seats and hardened exhaust seats. We also shimed the stock valve springs to add a bit more seat pressure for once the turbo was installed. A few rocker studs were replaced and we were back in business. The head went on and we verified good cylinder pressure on all. All that was left was to install the rest of the valve train and bolt the motor up. We were able to test fire it and it ran smooth, now sure it could use and will need rings eventually but that will come another day.

NEXT: TURBO PARTS AND FABRICATION