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The Silver Buick's 1969 Firebird OHC six project.

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  • It looks like you have a reverse cooling setup there, is that right? Enters in the head and goes out the t stat housing on the block? Any concern with air aboe the inlets on the head? Or is that how the factory did it. I look forward to seeing it at drag week!
    1968 Plymouth Barracuda Formula S 340 with a 360
    1997 Jeep Cherokee off road toy/driver. lifted, lockers, stroked 4.0

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    • It's definately not how the factory did it. I reversed the cooling system to keep the iron head as cool as possible as an added measure to stave off detonation. There is no thermostat in the housing where the OE water pump used to be, the outlet just made a convient hose connection.

      The original thermostat location is at the top of the cooling system in the cam housing, I have a plate sealing it with a removable plug to vent the the air bubble at the highest point in the cooling system. Nifty enough, with the engine off I run the pump at full speed, top off the radiator, vent the air bubble, top off the radiator, cap on, done. Minimal air in the system. If any bubble gets trapped in the cam housing its not a big deal, the heat is in the head, the housing is aluminum to disappate heat and will be under the most pressure coming off the pump.
      Escaped on a technicality.

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      • A stack of parts showed up this week. I picked up a set of 3" exhaust tail pipes. I want to run the exhaust all the way out to the rear. I'm not sure yet if I want to neck down to 3.5" on the down pipe then 3" just before the rear axle or go down the 3" at the bottom of the 4" down pipe and out the back. Folks say at my power goals I'm likely fine at 3" after the down pipe, but I'm weary.



        I mocked up on the left side, but I will be using the right side as I have all the fuel system running out the left, plus the turbo is on the right.


        I got a custom harmonic balancer put together. An engineer I know did the fabrication of an outer ring and a bolt on weight for his car to match the OE 4bbl balancer that is near impossible to find (can't even find a picture of one on Google!). But he never got it put on a center hub. I had Dampener Dudes in northern California put it together for me. I need to find the allen bolts and bolt it into place. I may have issue now with my crank trigger wheel. I need to check the diameter and may have to do something different. Worse case I used my 1bbl balancer for the duration of Drag Week. Dampener Dudes did a fantastic job. Lined up the timing marks perfectly.



        I also got an LED display to put in the hood tach housing. I tested the LED display in my Skylark. It was reading about 4x more rpm than it was running, so I think I need to make a reference/pullup circuit for it to make it read right. I'm slightly concerned it may refresh too slowly to be of any real use, but I'll reserve judgment until I get the reference circuit complete. It was only $10, so not big loss if it doesn't work perfectly. I'm thinking of wiring it into a 3-position toggle switch and be able to switch it to display MPH as well. I'm also going to put some indicator lights in the housing, like a shift light, check engine, etc.


        I also got in a 250amp fuse and case I need to wire in at the back of the car, as well as larger ground cable, so I need to re-run the ground cable. The engine bay looks so empty without the turbo!
        Escaped on a technicality.

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        • as you well know, I suffer from "analysis paralysis" ... so I would suggest you go for the 4" down pipe now, and split it for 2x3" with one of these
          Flowmaster Y300400 - Flowmaster Scavenger Series Y Collectorscuz you know you will change it later. Is there room for it? Could always put a cutout on one of them if you start getting too much drive pressure.

          https://www.summitracing.com/parts/f...ent=Flowmaster
          Last edited by Beagle; June 16, 2018, 06:42 AM.
          Flying south, with a flock of bird dogs.

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          • As far as the tach calibration: lacking your skills I bought a tach calibrator box from Dakota Digital. It took a bit of fiddling but I got the Volvo tach to work properly with the 347. Basically, it's designed to calibrate anything to anything. Worth a look.

            Dan

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            • Sizing your exhaust will matter a little on how long the downpipe actually works out to being. You'd probably be surprised at how much power you can shove through a fairly small-bore pipe, if the temp has dropped and they've contracted down a bit. Unless you're going for every scrap of power, in which case you'd be just dumping it as close to the turbo's flange as you could swing safely.

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              • I got a handful of internet opinions that generally concur that 3" pretty much right after the turbo will unlikely effect my "600HP" goal. The turbo outlet is 3.5" and the only reason I have a 4" on it is because I got it for $20. Realistically cost will be the reason for which ever exhaust I go with. I think the cost for 3.5" tubing is a lot more than 3". I'll be re-looking at it soon though. Reducing from 3.5" to 3" near the rear axle shouldn't hurt anything for sure. I want to keep it single exhaust because it being an inline engine, and I plan on keeping all the fuel side on the driver's side of the car.

                I need to find or buy new bolts for the balancer and get it to the machine shop so they can do the final balancing. Hopefully it's zero balanced or I can ask for it to be.

                Got the 4L60e I'm going to have professionally built put into a GM transmission crate I'm borrowing from a local guy that is on one of the inline engine forums I'm on. Hopefully will be shipping it out this week.





                In the mean time, after I get the Firebird up and running again, I need to install this older 4L60e that I put a mild shift kit in but is really in unknown condition otherwise. I can "practice" my transmission tuning and setup on this one to make sure I have everything setup right before the good transmission gets back.
                Escaped on a technicality.

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                • If you have concerns on the exhaust just get one of those valves that open under boost. You can cruise nice and quite and the exhaust will open up when under boost. I'm with you though I don't think you would have much of a power drop with your current plan.
                  1968 Plymouth Barracuda Formula S 340 with a 360
                  1997 Jeep Cherokee off road toy/driver. lifted, lockers, stroked 4.0

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                  • I have 3" (stock) exhaust on Truck (the Dodge/Cummins). Edge told me that bigger exhaust would do nothing until I was at least in the 600 HP range - and they could have sold me an exhaust system. Not sure if that rule of thumb applies to Otto cycle or not but it IS a place to start.

                    Dan
                    Last edited by DanStokes; June 19, 2018, 07:57 AM.

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                    • Well I am shooting for the 600HP range

                      As I've always heard it, the bigger the pressure differential between the drive side and exhaust side the better it works. No exhaust has the least amount of pressure, big exhaust the next best. Because the turbine smooths out all the cylinder pulses there is less exhaust scavenging that can be achieved from pipe sizing, etc.

                      I looked up the exhaust pipe costs, now I'm not sure what I want any more =P Ground clearance of course should be a concern.
                      $31 - 3.0"
                      $32 - 3.5"
                      $44 - 4.0"

                      Escaped on a technicality.

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                      • If you go with the 4" downpipe and it goes back to the middle of the car, the cost difference shouldn't make that much difference between 3.0 and 3.5" for the last half. Doublecheck muffler cost and availability also though, because that'll be the other major headache of the exhaust.

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                        • The 4" downpipe is definitely happening. Not going to run a muffler at this time, at least not until post Drag Week. The engine is pretty low compression so I'm letting the turbo "muffle", then take it out to the bumper so I really don't have to hear it if it is a tad loud

                          The bottle neck will be the 3" tail pipe over the rear axle. So it will be stepping down, but rather that is 2 feet behind the turbo before it turns 45º to go under the car, or several feet back near the rear axle.

                          Escaped on a technicality.

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                          • I don't think I had posted some of the exhaust pictures. I've made a few small changes since these pictures that pull the exhaust a bit more away from the firewall.

                            I took about an inch off the exhaust at the turbo flange end. Cut it at the back side of the welded seem and re-tacked it to the flange.




                            I need to re-make the transcooler lines.


                            Again, it's about an inch further forward now.
                            Last edited by TheSilverBuick; June 20, 2018, 07:18 PM.
                            Escaped on a technicality.

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                            • If you can stay 4" to the axle, you'll be golden.

                              Keep it as big as you can, as long as you can...

                              ...Then, pick a punchline, ('That's what she said', 'I hear that a lot', 'Whaddya mean another four feet', 'That extra inch really matters') or make up your own!
                              Last edited by AndyB; June 21, 2018, 07:51 AM.

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                              • You know i searched high and low for a good option to make my whole EFI harness disconnect. I never once thought about using the same connectors that are on the ECU lol.

                                I think you are golden on the exhaust I wouldn't sweat the 3" being that far back.

                                1968 Plymouth Barracuda Formula S 340 with a 360
                                1997 Jeep Cherokee off road toy/driver. lifted, lockers, stroked 4.0

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