Worth pulling /6 to "freshen up"?

Slant 6 Engines

  1. briwill70

    briwill70 Well-Known Member

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    I'm in the process of installing a super six intake/Weber carb and electronic ignition in my slant. Already have a 2.25 exhaust. Engine ran well and doesn't smoke but was lacking power. I just picked up an engine hoist cheap so considering pulling the engine to replace the timing chain, oil pump and adjust the valves. There is also a large dent in the oil pan that I want to fix. Anything else I should address? Worth doing a cam swap?

    IMG_8559.jpg
     
  2. halfafish

    halfafish Damn those rabbits, and their holes! FABO Gold Member

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    It depends on how "fresh" you want your freshen up to be. What are you goals with the car, and how will you drive it? What year and model are you working on? Freshening can be no more than you anticipated, or a complete tear-down to check for bearings and clearances.

    A good first step is do a compression check. If it's good, a cam change can help things out. Oregon Cam is local and can regrind your cam for about $80 or so. If you have more ambition and deeper pockets, figuring out your compression ratio will tell you if milling and/or porting the head is worth a shot. These engines are notoriously low-compression and don't breathe all that well from the factory. Fixing both of these can make a noticeable difference.
     
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    • briwill70

      briwill70 Well-Known Member

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      It's a 65 Dart 225. Eventually I want to rebuild it but also want to be driving it soon. Will probably just do timing chain, oil pump for now and see how it runs with the new goodies. Good point about the compression test. I should do that before I pull the engine.
       
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      • rklein383

        rklein383 Well-Known Member

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        I would do the compression check before pulling....everything is hooked up and it will be much easier.
         
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        • diymirage

          diymirage HP@idle > hondaHP@redline

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          i would have the head shaved .100 or so
          that will bump your compression ratio, which will help across the powerband and increase the gains of every other hop-up part
           
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          • briwill70

            briwill70 Well-Known Member

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            Happy to report that my compression test was 140-150psi on all cylinders! I also removed the valve cover and it is spotless under there. I assumed my engine had never been touched since it sat for 20 years but apparently it was rebuilt at some point.
             
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            • RustyRatRod

              RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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              You're over halfway there, so why not? If you don't mind me asking, which Weber are you going for? I am seriously considering a 32/36 for my stock 170. Thanks.
               
            • briwill70

              briwill70 Well-Known Member

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              It's a 32/36. I ordered the K551 Jeep conversion kit with adapter plate. Under $300 and it bolted right up to the Super Six intake.
               
            • RustyRatRod

              RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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              Keep us posted about the outcome. I believe you're going to find the 32/36 is not enough for a 225. It only flows 240 CFM. Really almost borderline for a 170, but that's the one I want to try. Good luck with it.
               
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              • 69a100

                69a100 Well-Known Member

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                I'm extremely happy with the performance & mileage of the 32/36 on a stock motor after fine tuning the jetting! I guess all those old posts over the last 10+ years about using it are now void and worthless info, but what do I know? Good Luck
                 
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                • briwill70

                  briwill70 Well-Known Member

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                  Good to hear! I'm excited to see how much better it runs with the Weber/HEI ignition.
                   
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                  • briwill70

                    briwill70 Well-Known Member

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                    Bummed to find this thick sludge in the bottom of my pan. This is after two oil changes and 30-40 miles. It looked like the engine was rebuilt at some point but appears the head was replaced but rest of the engine is original. Guess I'll be looking at all my bearings now : (

                    IMG_8573.jpg
                     
                  • halfafish

                    halfafish Damn those rabbits, and their holes! FABO Gold Member

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                    Yuck! That looks like a mudslide!
                     
                  • briwill70

                    briwill70 Well-Known Member

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                    I pulled a rod bearing and it looks ok. May track down a Plastigauge and check the clearances. Really don't want to pull the head since compression is good. Hope to just clean it up and put it back together. Sound reasonable?
                     
                  • RustyRatRod

                    RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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                    Sludge in the bottom doesn't necessarily mean everything's bad. Mine sat up since like 1980 until I bought it and got it running in January of 2019. I did an oil change and replaced one quart with Marvel's Mystery oil. Ran it for about 500 miles and changed it again. Replaced a quart with MMM again. Drove it for three months like that and changed it once more to full synthetic. You should have seen how black the oil was the first time. It wasn't too bad the second. I am still on that third change now. Probably finish the year out with it and change it again. Probably go to a 5/30 full synthetic. I have 10/30 synthetic in it now.
                     
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                    • Slantsix64

                      Slantsix64 Well-Known Member

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                      Yup swap that camshaft while your in there, your adding gas and exhaust upgrades so get the full benefit of a aftermarket cam being able to have those valves open for longer durations and higher lift ratios. stock camshafts are more mild than taco bells mild sauce.

                      I had a single weber Carb on my slant six idled smooth at like 450 rpms but the two barrel holley 2280 was more effective and didnt have a little lag at WOT like the weber. but everyone had different results Good Luck!!!
                       
                    • briwill70

                      briwill70 Well-Known Member

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                      Well, here I go. So much for the quick refresh. I've completely disassembled the slant. Most of it looks ok but bearings show signs of oil starvation. Plan to polish the crank and new bearings. Cylinder walls look good but there is a bit of a ridge at the top. Not sure if it's worth the machine work to address this. Is there a threshold for how much ridge is too much? Hope to reuse the pistons/replace rings. Dropped the cam off for performance re-grind. The head looks good and was obviously cleaned up at some point and has new seals. Exhaust valves look good and are not sunk in/burned up. How can I check to see if the head has been shaved already? I'd like to increase performance since I've gone this far. Recommended head gasket to use?
                       
                    • halfafish

                      halfafish Damn those rabbits, and their holes! FABO Gold Member

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                      If I can catch a fingernail on the ridge, I would at least dingle-ball hone it out. And check taper and wear just in case it needs to be bored.

                      Did you CC the chambers? This will help figure out if it's been shaved or not.
                       
                    • diymirage

                      diymirage HP@idle > hondaHP@redline

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                    • briwill70

                      briwill70 Well-Known Member

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                      Thanks! Based on the coolant tube, it has not been cut. I will have to rig up a way to measure the CCs.
                       
                    • pishta

                      pishta I know I'm right....

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                      invert head and take a CD and vaseline the fire ring of the chamber and lay the CD on top, its hole as far from an edge as possible. Now fill it with alcohol from a medicine dropper that has graduations on it. Make sure the head is completely level. Count how many CC's go in before the alcohol starts to fill the spindle hole. this will give you a pretty good estimation of cc size of chamber. You can use water too but alcohol has less of a meniscus (curved area of fluid in a test tube or similar). Youll find your head CC is grossly more than spec's in manuals. If you got the head off, Id look into milling it as perscribed, up to .100 but watch for retaining pushrods adjustablilty, there must be a limit on how much you can mill without going to a shorter pushrod? Good news on the seats being good.
                       
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                      • my68barracuda

                        my68barracuda Well-Known Member

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                        Tractor Supply Syringe is a cheap and ez way to measure the fluid

                        https://www.tractorsupply.com/tsc/product/producers-pride-60cc-syringe-with-catheter-tip

                        a 5 x 5 piece of plexiglass with a 1/8 inch hole drilled into it is a functional and accurate cover plate. Install a spark plug to block that hole, use vasoline as mentioned above. I set the head with either the spark plug side down or the manifold face down, with the drilled hole at the very top of the chamber inject the fluid, I use water with a bit of food coloring, till the combustion chamber is full,,,,

                        oh yea,, an uncut stock slant six head combustion chamber will be around 58 cc's
                        some are a little smaller, some a little bigger,,,,,
                         
                        Last edited: Jun 4, 2020
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                        • halfafish

                          halfafish Damn those rabbits, and their holes! FABO Gold Member

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                          Also, I forgot to mention if you need tools to check your cylinder and lifter bores I have them and we are neighbors.
                           
                        • briwill70

                          briwill70 Well-Known Member

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                          Nice! I will send you a message.
                           
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