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High Tech Pontiac OHC L6
It's a slow day around here so I though I'd pop this up on another forum incase anyone else found it interesting, and to justify a Buick guy on a Pontiac board :p I've been working on building an OHC straight six engine, well actually it'll eventually be two engines, but this first one is more or less proto-typing for my good build that will involve a custom intake and sufficiently sized turbo along with a ported head and a re-ground race cam. It'll be ran with sequential fuel injection with COP ignition all controlled by a MegaSquirt 3.
The main build can be found here: http://sohcsix.yuku.com/topic/2700/G...serious?page=1 This engine here is a '69 250, with a '69 1bbl head and '66 4bbl intake and exhaust manifolds. The head and bottom end were pulled apart for inspection then put right back together, rings, bearings and all. The 1bbl cam was toast, so I have a good used 1bbl cam to start the engine up with and if it does well I have a new 4bbl cam to install. The modification list to date include: 1) Removed the restrictor/orfice tube and replace it with a straight tube 2) Drill and mount an external oil pressure regulator to the head and lash adjuster galley 3) Replace the main oil pressure relief spring with one that should boost pressure to ~60-80psi. 4) Drilling the intake manifold and JB welded injector bungs into it 5) Mounted LS coil packs to the engine. 6) Modified the points distributor for a cam sensor Here are a couple older pictures. Ignore the rubber hoses, it was an idea I abandoned. http://sphotos-b.xx.fbcdn.net/hphoto...50516405_n.jpg http://sphotos-b.xx.fbcdn.net/hphoto...46858816_n.jpg http://sphotos-b.xx.fbcdn.net/hphoto...69281587_n.jpg http://sphotos-b.xx.fbcdn.net/hphoto...57161659_n.jpg I've built part of a rudimentary engine run stand to test out the oil pressure modifications prior to installing the engine into the car. Of course it'll let me test the EFI set up as well. I still need to make the control panel among a few other minor details. https://sphotos-b.xx.fbcdn.net/hphot...25425717_n.jpg This is how it sits today. The fuel injectors are wired up and the ignition coils are partially wired up. I'm starting to feel like I can see light at the end of the tunnel! https://fbcdn-sphotos-g-a.akamaihd.n...75888028_n.jpg https://fbcdn-sphotos-e-a.akamaihd.n...03049476_n.jpg I'm particularly proud of my cam sensor. I just hope it works! (it should) https://fbcdn-sphotos-d-a.akamaihd.n...25655547_n.jpg And the car it's going into is a '69 Firebird. I've already changed out the motor mount brackets for the L6 ones, but still need to plumb the fuel lines and do some minor wiring. I have a 2004r that I'm going to rebuild to stick behind it. The MegaSquirt should do a good job of controlling the lock up converter :cool: I'll probably start looking for a 4L65e down the road when I go turbo. http://sphotos-b.xx.fbcdn.net/hphoto...14507369_n.jpg And the car patiently sits in a horse stall waiting for it's new engine :) http://sphotos-b.xx.fbcdn.net/hphoto...35598444_n.jpg |
BadAss!!!
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GAWD, I want one!!!!
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Can't wait to see the results. Great project!
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Really neat project, and tasteful engine details.
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Thanks! I'm headed out on a two week vacation, but when I get back I plan on finishing up the wiring and plumbing.
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So after a dozen or so side tracks I started up working on this again. I didn't take any pictures of it, but I installed an OHC starter nose cone on a Buick 455 starter for a bit more oomph starting up.
Got the project work board out for this one. I've added a few things to the list since I took the picture, like add oil and prime the system. https://scontent-a.xx.fbcdn.net/hpho...32403369_n.jpg Got the exhaust system for the run stand sorted out. I may have to cut the pipe just before the bend and adjust from there once in the car, this will do for now. https://scontent-b.xx.fbcdn.net/hpho...44851769_n.jpg. No where in Ely sells exhaust reducers so I had to improvise. So a few slices, some hammer taps and some welding fill. Due to my (lack) of awesome skills I had to fill a lot of gaps where the second pipe slide into that hole. https://scontent-b.xx.fbcdn.net/hpho...66329200_n.jpg I also fabricated up the crankshaft sensor mount as well as did final mounting of the alternator, complete with new belt. https://scontent-a.xx.fbcdn.net/hpho...19217208_n.jpg Got the sensor wiring routed safely around the exhaust. I'll put the alternator charging wire into the black loom when I wire it up. https://scontent-a.xx.fbcdn.net/hpho...83852203_n.jpg Tomorrow's plan is to work on the fuel system and finish up the wiring. |
Been doing some work on this and updating the yuko thread, so I'll copy the posts over.
Got the fuel side more or less done including the rail hold downs. I cleaned and gasketed the Q-jet as well. It was the grimy-est one I had so it only marginally cleaned up. I just remembered I need to add an O2 bung to the exhaust collector. I started to do some wiring, but wasn't in the mood to do it so will get to it later. I'm trying an unconventional way of setting the fuel system up by not having the fuel rail return at the far end. I am monitoring fuel pressure at the end of the rail opposite side of the regulator, so if there are issues at the end it'll present itself. It should work similarly to the return-less setup, in theory.... https://scontent-a-dfw.xx.fbcdn.net/...12540733_n.jpg https://scontent-a-dfw.xx.fbcdn.net/...61608430_n.jpg Set the timing belt cover on it for a few pictures. https://scontent-a-dfw.xx.fbcdn.net/...63687035_n.jpg https://scontent-b-dfw.xx.fbcdn.net/...51961352_n.jpg https://scontent-b-dfw.xx.fbcdn.net/...14504808_n.jpg |
And..
Finished up the main wiring on it today. I still have to make my two connector plugs at the rear of the engine though. I installed the O2 sensor that I had forgotten to do and had to switch to the Holley throttle body due to me being an idiot. The way the Q-jet is oriented on the intake the throttle isn't pulled, it's pushed and for some reason that didn't click with me until today when I was looking to set up the return spring and start on the throttle bracket with a 200-4r cable. So with the Holley I flipped the direction or the primaries and secondaries to put the linkage on the other side and in a pull situation. I knocked out the venturi's and made some plates to seal up where the float bowls used to be also. Here is how it sits right now. I'll tie up the red power wire with the crank sensor wire before it's all done. I debated what color to paint the block off plates, but ultimately Pontiac Blue won. Red, black and silver were the other options. I forgot to take a picture of the other side of the engine, I have the wires pretty much loomed up. https://scontent-a-sjc.xx.fbcdn.net/...97073184_n.jpg Like the Q-jet, this thing was pretty grimy, so it only cleaned up so much, but looks a ton better than before. I have linkage brackets on order and should be in next week. https://scontent-b-sjc.xx.fbcdn.net/...42342838_n.jpg Some one was asking how I mounted my air temp sensor. I took the sensor to the hardware store, found a grommet that it fit tightly in, used a stepped drill bit to drill a hole in the base plate for the grommet and done. https://fbcdn-sphotos-d-a.akamaihd.n...03931045_n.jpg |
And where it is today.
Solving not having the 4bbl pivot and lever brackets by running a holley center section backwards. Works like a champ. I will probably weld a steel pulley wheel to the bracket to support the 90*ish turn in the long run. I stood behind the engine about where the cable would go into the firewall and had no problem actuating the throttle and it returning properly. https://scontent-b-lax.xx.fbcdn.net/...57224381_n.jpg |
Looking great! Did the similar mod to my 1994 Trans Am and converted the LT1 to run on a LSx PCM and run LSx Coils for ignition. Really debating what to do with my newly aquired motor i have on the stand to ready to build.
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may want to look at the Bosch throttle body for a FI Seville
its basicly the back half of a Q jet |
Hadn't updated this thread in a while. Here are some updates. I may actually start it up this weekend!
Finished the connectors on the engine. https://scontent-a-lax.xx.fbcdn.net/...29752359_n.jpg I pulled the wiring harness off the engine and cleaned it up. Took about 5 minutes to pull it off the engine. https://scontent-a-lax.xx.fbcdn.net/...47552619_n.jpg Finished up the main wiring harness as well. The quick connects plug right into the engine harness. Most the other wires probably won't be used and will be trimmed once installed in the car. The only wires outside the plugs that will be needed is: +12v power, O2 sensor in, Fuel Pump trigger, and torque converter control. I intend on adding a vehicle speed sensor and possibly a couple pressure sensors for fuel and oil and possibly electric fan control. Some of the other wires might come back into play for boost control down the road. https://scontent-b.xx.fbcdn.net/hpho...33626637_n.jpg . I assembled the valvetrain, set the cam timing, topped off the oil and started priming the system. I also made a custom valve spring compressor tool for this engine so I can change the springs down the road when I upgrade the cam. Here is the used C-cam. Its the 175HP 1bbl cam. Figured I'd use this cam to get the engine running and driving and after I have the car on the road for a while I'll swap to a bigger E-cam, 215HP 4bbl cam. Notice the cam lubricates the followers directly. https://scontent-b-lax.xx.fbcdn.net/...67584307_n.jpg Here are the lash adjusters in place before I set the cam housing on. https://scontent-b-lax.xx.fbcdn.net/...31505546_n.jpg The stock oil pressure is set at around 30psi, so I swapped the stock relief spring with a spare Buick white spring I had, which is supposed to be 60psi in the Buick (my experience says 75psi). I primed the system up and the system pressurized to 95psi, so I cut three coils off and it dropped to 70psi, which I am good with. https://scontent-a-lax.xx.fbcdn.net/...33917255_n.jpg https://scontent-b-lax.xx.fbcdn.net/...38726789_n.jpg I made a valvespring compressor for when I go to upgrade the springs down the road. I took a spare 9mm allen wrench and a universal stamped steel Buick rocker arm and began cutting, grinding and welding and came up with this. The T shaped one has a notch at the end to hook the oil galley in the lash adjuster hole and I welded a nub on the end of the rocker arm to keep the T part from sliding out. I stuck a standard 6 point impact socket and extensions on the end of the allen handle for extra leverage. I'm considering cutting down the allen handle and simply using the socket and extension for the lever. More compact. https://scontent-a-lax.xx.fbcdn.net/...96764553_n.jpg In action. I originally left the loop on the rocker in place, though shaved a bit, for structural reasons, but I think I can safely remove it if I box in the rocker below the allen shaft and on the other side between the opening and slot for the T. https://scontent-a-lax.xx.fbcdn.net/...14638050_n.jpg Got the external oil line and regulator working. I had to down size the feed line because it was bleeding off the main line pressure as well. Right now I have a temporary 1/8th inch fuel line (rated to like 120psi..) for the external line, but I'll order up something more permanent. Worse case I'll go with some copper line since there isn't any flexing once installed. I need to come up with an oil return location. there is a rubber plug on the side of the oil fill tube so I might install the return into that or make a new oil fill cap with the return line fitting on it. An interesting observation on the main line oil pressure gauge. I noticed this gauge takes a while to show pressure build up compared to the electric oil pressure gauge on my Skylark when I did a back to back test. On this engine both oil pressure gauges come off the same tee and one is clearly slower in responding, the one with the long plastic line. I think the air in the line causes the long delay and slow response in oil pressure, which is a common thing in mechanical oil pressure gauges. http://www.youtube.com/watch?v=DcDLi...Jo4BJ5Am4jH-sA Got the shop and tools cleaned up and organized today. Got the engine back on the run stand and found some radiator hoses from NAPA. Hopefully the radiator doesn't leak =P I'll get two mufflers ready for testing as well. Getting ready for install, hopefully no serious hiccups when I do the fuel pressure test and start up. https://scontent-a.xx.fbcdn.net/hpho...71383129_n.jpg https://scontent-a.xx.fbcdn.net/hpho...20500045_n.jpg Due to a friend's huge generosity I may be going to a reverse flow cooling system sooner rather than later! He said he has an automotive electric water pump and controller that is about ten years old but had never been installed/used that he is just going to give me! So I went down to NAPA and asked them what the largest diameter heater hose they keep in stock was and I was delighted to hear they had 50ft of 1" heater hose. So I went to the hardware store and picked up a pair of 1" steel water nipples and welded them to a pair of steel freeze plugs. Due to heat while welding, changing the inside shape, etc I may have to find a way to positively retain them in the block. Like a set screw or plate. I'll cross that bridge later. Here is a pair of mock up photos. https://scontent-b.xx.fbcdn.net/hpho...14042068_n.jpg https://scontent-b.xx.fbcdn.net/hpho...57879845_n.jpg Oh yeah, started on a control panel as well. Just have to wire it up. https://scontent-a.xx.fbcdn.net/hpho...55562833_n.jpg |
I was looking at my exhaust options. Basically either half the Skylark's old exhaust or half the Firebird's old exhaust. I cut the Firebird's old exhaust in half. I thought about leaving the dual part from the X-pipe back, but opted against that. I should have enough exhaust stuff to be able to cut out and replace the remaining X-pipe piece with a good piece of mandrel bent tubing. On the right is 2.5" Skylark mandrel bent exhaust from a Summit universal kit complete with Summit brand muffler. On the left is what came with the firebird which is 2.5" regular bent exhaust with Flowmaster mufflers, I think 40 series but don't know for sure.
https://scontent-a-iad.xx.fbcdn.net/...04717935_n.jpg I should be able to make some quick back to back tests on how each sounds. The Summit brand one bolted up. https://scontent-b-iad.xx.fbcdn.net/...57722300_n.jpg The Flowmaster brand bolted up. https://scontent-a-iad.xx.fbcdn.net/...26578868_n.jpg Wired up the control panel and megasquirt. It's pretty hokey but it'll get the job done. That battery is an old one out of my Skylark that I am pretty sure has a dead cell in it. I have the charger on it now and I think it'll get the job done just fine. It never up and quit on me, but would instantly drop to ~11.9 volts when the key was turned off, but would start fine the next day or even several later from 11.xx volts. https://scontent-b-iad.xx.fbcdn.net/...50522808_n.jpg https://scontent-a-iad.xx.fbcdn.net/...37387642_n.jpg The outriggers for some anti-roll support. I won't get too crazy with revving it if things look shaky. https://scontent-a-iad.xx.fbcdn.net/...24124667_n.jpg As the car sits right now waiting for rear gears and all the other work. https://scontent-a-iad.xx.fbcdn.net/...41414977_n.jpg |
You need a video asap lol... too many pictures of it sitting there just waiting to fire up!
What gear is currently in the car? |
Crossing my fingers for a tomorrow fire up. I'll test the ignition system then the crank and cam signals then pressure up the fuel system and if it doesn't leak I'll fire it up.
It has a chevy 8.2" with 2.73 gears. I'm waiting for a 3-series carrier to show up for the 4.56 gears I have. I bought a mini-spool for it too. |
For those not tracking this on another forum, I didn't get to fire it up due to the fuel rails not performing to expectation. Below are posts of the last two weekends.
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1/8 mile or 1/4 set up?
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Fun set up? The gears were $100 new (with bearings, seals and gasket) from a guy I know so I couldn't pass them up. The overdrive keeps it all livable.
I don't know, what do these engines normally trap in the 1/4? 5500rpm in 3rd is 94mph, which seems optimistic for a 1/4 mile speed. Wallace racing calculator thinks 91mph at 3500 lbs and 215HP. Both weight and HP are assumptions. |
Which cam again? E? My 255 with basically an H cam made 200 HP. 215 is the old "gross" HP rating.
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