Holley 1850-5

Discussion in 'Fuel and Air Systems' started by Kendog 170, Oct 12, 2018.

  1. Kendog 170

    Kendog 170 Member

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    Hi All,
    I just inherited a Holley 1850-5 it has vacuum secondary's . Has anyone used this on a 340 4 spd ? I always liked mechanical secondaries myself. Also 600 CFM. It's a street car no strip but maybe a touch small with 20 over with Eddy heads . I am looking for some gas mileage .My AVS is giving me issues after a rebuild so I thought I might try it. I'm thinking Looking for a few opinions.
    Thanks
     
  2. JBurch

    JBurch Well-Known Member

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    Try it, the worst that will happen is you'll hate it; OR, you'll love it. Street car, just driving around, enjoying the day, the ride, it will work just fine. Tuning will be required for secondary opening and pump shot.
     
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    • toolmanmike

      toolmanmike FABO Staff Staff Member FABO Gold Member

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      What's your AVS doing or not doing
       
    • brian6pac

      brian6pac Well-Known Member

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      I like the AVS myself but the 1850 is a great carb also and will most likely need some tuning to get it perfect, it's a universal carb and that's why a lot of people don't like them, sometimes they don't work right out of the box you have to tune them.
       
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      • toolmanmike

        toolmanmike FABO Staff Staff Member FABO Gold Member

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        or you can mess up the accelerator pump springs and get a off idle bog that can't be tuned out. Could be something simple with your rebuild.
         
      • rumblefish360

        rumblefish360 so close yet so far away

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        I have run both carbs and they performed in the 1/4 about the same and I have gotten the same mileage out of both of them on a mildly built 318.
         
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        • AJ/FormS

          AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

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          I tried it on a 360 4-speed; not nearly big enough. So I modded it lean on the primary side and it became my hiway carb.I fattened up the secondaries a tad to average it out at WOT, and it makes enough juice to pass.
          I agree that the DP is a better manual-trans option. We don't have the Torque-multiplying fluid coupling advantage, nor the slip from idle to stall, So if you're down there, and the tires won't spin, it's a bit of a wait to get to where the power is. And that is where the DPs shine; a lil toe on the clutch and stomp on it and G-o-n-e is you.
          With a 360, just stompit.
          Theoretically it is big enough, for the stock 340
          Depending on your cylinder pressure, it can make or break your combo.Modding it lean is not for the faint of heart. That is much easier done with a metering-rod carb, if you can get a kit for it..... like the Edelbrocks.
           
          Last edited: Oct 12, 2018
        • Kendog 170

          Kendog 170 Member

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          Thanks for all the responses. I guess it can't hurt to try it out. Give me time to see whats up with the AVS .
           
        • Kendog 170

          Kendog 170 Member

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          Actually I now think the carb is fine. I just went through the motor, 20 over KB pistons ,Same crank, same cam, Eddy heads 60175, Motor sounds good at idle but acts like a severe vacuum leak or like timing marks are off. Stalls , won't accelerate properly. I know I aligned it correctly for stock setting. Timing is at 8 BTC 35' Total. Motor was tired but ran good but sat 10 years before rebuild.New Gas tank and stock fuel pump . I have 15 in. of vacuum at idle .Not sure if this is low for stock 1968 4 speed cam but can't recall what it use to run at . Comp to me is little high at 180 . In the process of moving so it's been hard to get to work on it. Have no Mopar mechanic friends to help .
           
        • Kendog 170

          Kendog 170 Member

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          My machinist who did my 500 inch stroker closed shop so I tried to do this myself (probably a mistake) but I have done a couple of prior successful builds .
           
        • toolmanmike

          toolmanmike FABO Staff Staff Member FABO Gold Member

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          If it were me I would try 15° initial timing or so and see if it likes it. If it kicks back against the starter back it down a degree or two. If it pings you can usually tune that out with the advance and the total mechanical advance in the distributor. Once you find that happy initial timing, you can always pull the distributor and send it out for a custom curve. I don't ever remember running a Mopar engine at stock timing specs and never less than 10°.
           
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          • AJ/FormS

            AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

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            What Mike said
            but instead of setting the timing to a number, You might try just pulling on the Vcan until the rpm peaks and then retard it enough to lose 100 rpm. This is ballpark for an automatic car with a 2500 or more TC. It will be waaay too high for your 340 stick car at 180psi, so don't drive it too deep into the throttle. But if it likes it, you will now know in which direction to take it.

            The reason I say this is too much for your combo is because reading between the lines, I'm guessing your rear gear is 3.23s or less, and coupled with a 2.66 starter gear and guessing 26.5 tall tires, this works out to 9.17mph per 1000 rpm. Idling it down to 600 in gear, which is easily doable, this makes 5.5 mph. With so much timing now ( I'll guess about 20/25*), and 180psi, the power pulses are gonna hammer into the suspension, and the shocks are gonna transfer them into the chassis, and the car is gonna start to buck, and if you let it continue, it will rattle your fillings out.
            So this method I posted above is just for diagnostic purposes.
            Mike is right about 15* in your combo; but you have to be sure your TDC marks are actually what the engine is seeing. If she liked the Vcan pull, then prove the TDC marks. If you already have, then get another light. If you have a multi-strike ignition, you cannot use a dial-back light on it, unless it is MSD's own lite.
            With a hi-compression stick car, IMO the initial should be set quite a bit lower than an auto. The Eddy heads will let you put a pretty fast curve in there. I run mine up to 28* at 2800, from 14*@1000, then I slow it down to 32/34* at 3400. This lets me run 87E10 without detonation. The curve could be a lil faster yet, but at 180psi, there is so much power I ain't chasing after a couple of ponies at 2800. If I am at 2800, it is because I am cruising or granny-shifting, otherwise I am blasting on by.
            Happy HotRodding

            Oh right, the vacuum advance should be plumbed to the sparkport, and the PCV fully operational,and plumbed to the underside of the primary throttle valves.
            15" of vacuum sounds close actually, altho I'm betting that is not at 700 rpm
             
            Last edited: Oct 17, 2018
          • Kendog 170

            Kendog 170 Member

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            I will start with the timing. I drove this car 100K miles with timing at 8' all in at 35' . Ran awesome. it was a Mustang eater in the 80's . You are right in assuming a 323 gear .
            I appreciate the advice as I am not the sharpest tool in the shed . It takes me awhile to get things right. I hope your all correct and my problems aren't deeper. Maybe I can get some time this weekend to play with it.
             
          • AJ/FormS

            AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

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            You're sharper than you think, cuz you came to FABO.
             
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            • Kendog 170

              Kendog 170 Member

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              Well I bumped up the timing and still have the same issues. I put the rebuilt Eddy carb back on and still the same. It seems to me I'm getting excessive steam out both exhaust pipes. I'm still running water (no anti-freeze while breaking in). No water in oil. I didn't pull the plugs but did when I did my compression check a while back and didn't notice signs of water. I guess I'll pull the plugs check for signs of water, maybe crank with plugs out, Check the balancer and confirm TDC, Thinking of pulling Intake and using the better felpro SFL1213S3 intake gasket set instead of the stock set from engine set.
               
            • Kendog 170

              Kendog 170 Member

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              Well I bump stopped #1 cyl. and found the balancer off 5 degress. So i guess when I was running at 8' for 100k miles it was actually at 13. Guess that's why it ran so good prior to rebuild. Motor still not right. Also at 800 rpm I have 13 in. of vacuum not 15 as previously thought. I might try a different dist. I have just to eliminate any possible issue there. I'm having a hard time thinking water port may be leaking into intake from intake gasket and not oil as well. I forgot to spin the motor while plugs were out so I guess I'll try that next.
               
            • AJ/FormS

              AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

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              With 13"@800@13*@180psi,this should be a dynomite combo.
              With the balancer index off, you will have to fix the power-timing, as 40* is too much. The Eddie heads don't need much more than 32*.
              Steam out the tailpipes at this time of year, with lots of humidity in the air is normal, especially during the warm-up period.
              "Eddy heads 60175, Motor sounds good at idle but acts like a severe vacuum leak or like timing marks are off. Stalls , won't accelerate properly." This obviously is not normal, and I think 13"@800 is perhaps a lil low for a stock 340 cam @13* Idle-timing. Between what I believe and what you are experiencing,and the fact that additional timing didn't improve the situation; I have to conclude that you have a modest vacuum leak somewhere.
              I would carefully examine the PCV system first. If you have a brake booster check the line and especially the ends,then clamp it off and note the engine idle speed and quality change. If none then remove the clamp. Then check any other vacuum lines and circuits that may be on the intake or carb. If all is good there,then move on to the carb base gasket, the intake ports and especially the underside in the valley. To check the valley, I put a vacuum gauge on the dipstick tube, then flip the PCV out of the valve cover, then seal both valve covers. Now start it up and watch the gauge; there should not be any vacuum developing in the crankcase, in fact, without the PCV, it should actually begin to build a pressure in there. That would be what I would expect to see. If you see pressure, do not let it it exceed 3 to 4 psi, as excessive pressure will blow out something; be it seals, or gaskets.
              I could be wrong on suspecting a vacuum leak, so if you don't find one then you can move along to the carb. But you can't start working on the carb until you are sure you don't have a vacuum leak. Well you could if you don't mind chasing your tail for a few hours.
              And it is imperative that you know EXACTLY what your idle-timing is, and that starts with finding true, #1-TDC.I don't know what "bump-stopping" is, just make sure you done it right. With 180psi, I would advise against too much more than 13* idle-timing as, the low-rpm when you engage the clutch or try to drive slower than curb idle speed, will get real jumpy; and with 3.23s @ 650 rpm, your minimum road-speed will be about 6mph. After that you will have to slip the clutch. I have to crank mine back to 5* with my dash-mounted dial-back timing device, so as to delay the jumpiness to 550rpm@ 4mph, Yeah they run down there if you get the t-slot tune right, and very sweetly I might add.
              So once you have your power-timing limited to 32/34 with the idle-timing at 13 to 15, then just make sure it doesn't come in too fast for 3.23s and a 4-speed. If you have 28* by 2800, that is fast enough.
              Now,after all that is done, you can attack the carb.
              But first; as to gas-mileage with a 340,with the stock cam, IMO forget about it. And the reason is, I recently found out, is because the cam is a lot bigger than the specs indicate. Mopar calls that cam a 268/276/114+4 but it is rated at at .008 tappet lift, and on that cam it is a looooooooong way from .008 tappet lift to intake actually on the seat.And it's the same deal on the exhaust side. So if you work out the valve events on that cam with the advertised numbers,and in at 110, you get ; intake duration of 268*, exhaust of 276*, compression of 116*, power of 104*, and overlap of 44*; which on paper looks pretty good.
              What you don't see is; firstly, that exhaust duration from sealed to sealed is actually an awful lot shorter than 104*, which means an awful lot of energy still remains in the expanding gasses when the exhaust valve actually opens. I'm gonna guess that that the valve actually opens as early as 90*ATDC....... which is fine for making power at high revs...... but for you at 65=2600rpm, it is lousy. Wait, make that; really lousy.
              Another thing you don't see is what is actually going on at TDC-Overlap. The advertised is only 44*measured at .008 tappet lift/.012 valve lift. So the valves are not actually closed YET!! Again, I'll guess that this sealed to sealed time is actually closer to , eh, actually I can't guess on the sealed to sealed, it could be flipping huge.
              So, now with manifolds this is not a huge deal with that early opening exhaust valve, but your intake manifold is still gonna see a lot of EGR at low rpms, hence the 13" at 800rpm. But that EGR wreaks havoc on tuning the carb, especially with the ring seal that is required to make 180psi. This all adds up to very poor engine efficiency at low rpms.
              But with headers it gets worse. Now the pipes, inertially tuned, are pulling on the carb during overlap, pretty hard; which is not just 44* seat to seat but some much much bigger effective amount,at low rpm, where there is plenty of time to yank A/F charge on thru.
              To get the best from this cam, in terms of fuel mileage, you need a cruising rpm that is at least as high as your vacuum peak, which is the lowest rpm that reversion is mostly stopped. So rev it up in neutral and watch the vacuum gauge. The manifold vacuum will rise to a plateau and then begin to fall. You wanna cruise on the plateau. The next thing is, on the plateau, you wanna give the engine the timing it craves, and that could be as much as 55/60 degrees. You might only have 26*@2600 in the mechanical +initial, so the rest has to come from the Vcan. But the biggest Vcan I have seen was 20*, which I have modified to 24*. So about the most you can get is 26+24=50*. To get more, you would have to increase the Idle-timing, and/or speed up the rate of advance. If you did both, you might get as much as 20+8+24=52* @2600 which is still not enough, but now you have the added problem of the jumpiness at 650rpm that 20* initial brings on. IMO, it is better to leave the initial at 14 and mess with the rate of advance, to achieve the same end-result of 28@2600.
              So that is why IMO, you will never get great mileage with the factory cam and 3.23s and a cruise rpm of 2600.
              Now throw into the mix, the 1850 carb, which has a fairly rich low-speed circuit, made worse by the cam, and forget mileage. You need that metering-rod carb so you can really lean out the cruise circuit....... but you can't lean it out until you get the timing maxed out. Then you lean it out. Then you increase the timing so you can lean it out some more. Then you hit a wall that no more timing ,nor any less fuelling, gets you any better mileage, and now the car doesn't even want to accelerate to cruising speed anymore, unless you get up on the mains........ and there goes the mileage!
              IMO
              I would pull that cam in a heartbeat. You can make equal or better power WITH better mileage, with a more "modern" cam.

              This does not speak to your current tuning problems, tho, I'm jus saying, not to expect much from the Mopar factory cam (used no less),in terms of fuel mileage.
              Don't even think about swapping the 3.23s out for 2.94s or less, it will only make less mileage on account of they will put you on the wrong side of the vacuum-plateau. Instead; drive faster lol.
              ____________________
              In the 60s, my dad and his brothers used to buy big-motor Buicks and Olds and such, cuz, they said, they got best mileage at 85plus mph. At 60 they sucked gas.But they had a hard time keeping tires on them in those days.
              I have a recipe for 32mpgs from a high compression 367......... I'd like to try it with a 3.79 stroke 340 one day,lol. That could be a 396 cuber at 4.08bore....... Yeah, 396......that has a nice ring to it.
               
              Last edited: Oct 29, 2018
            • Kendog 170

              Kendog 170 Member

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              WoW! If I had to type all that I would be up all night! LOL . When I said bump #1 cylinder I meant finding true TDC which as I was saying when I thought I my initial was at 8' it turns out I been at 13' . As for Vacuum leaks I've blocked the PVC off and the V can (no change). I have no other vacuum ports other than a capped hose port on intake for my dash mounted gauge. I'm curious what Cam you would choose for my combo in case I decide to go down that path in the future. I agree the steam in the exhaust is probably nothing to worry about as of yet. My brother has a friend that is really smart with any vehicle and I'm hoping to get him over to give me his opinion. I like the Dip stick tube test , I'll try that . I will stick with an AVS when problem is solved. Thanks for the reply I appreciate it.
               
            • Kendog 170

              Kendog 170 Member

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              Oh yeah, at 180 compression what compression ratio do you think I'm at. I tried figuring it on a calculator but got me a little confused. I thought I was around 10.5 or 10.8 to 1 .
               
            • AJ/FormS

              AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

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              That's a really tough question at the best of times, but with a 268Mopar cam it's even harder.
              And it really doesn't matter. The engine doesn't make power with compression ratio; it makes power with cylinder pressure, and if your 180 is accurate, that is plenty of pressure.
              If I had to guess, I'd say over 10.8, but less than 11.2.... that is a straight up guess.
               
              Last edited: Oct 31, 2018
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              • rumblefish360

                rumblefish360 so close yet so far away

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                I think that is a pretty good guress. It isn't easy telling the poster what he has based on PSI readings because of the cam. Install another cam and the pressure will change. Bigger cam, less pressure. If you could measure it for a static ratio! That would be really good.
                 
              • Kendog 170

                Kendog 170 Member

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                OK, well your talking way over my head. I'm just worried about running on pump gas as it's just a driver. Maybe get a a thicker head gasket to help on that or am I over thinking this?
                 
              • rumblefish360

                rumblefish360 so close yet so far away

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                Did it run on pump gas before any issue?
                If so, it will do just fine again.

                On talking over your head on the ratio thing .....

                Cranking psi rated @ 180 per yourself is a great way to understand what is going on inside the engine on a dynamic level. As the engine spins, it is trapping enough air (&fuel) to create 180 psi which is enough to feed adequately a certain amount of camshaft duration.

                On the wish to know what the static compression ratio is, it is a bit hard to determine what it could be because the camshaft is unknown and a cam will change the dynamic ratio up or down depending on the cam size.

                Let’s take some numbers that don’t mean anything or add up for a obtuse example.

                If you knew the static ratio was 9.5-1...
                and camshaft “RRR” is used, you get a reading of 180 psi. This value can change with a different cam. Installing a longer duration cam will lower it.
                Install “YYY” cam and the dynamic ratio drops 10 psi to 170 psi. This could be a problem because the “YYY” cam is 10* larger.

                The problem becomes a camshaft reducing the psi to a more octane (& wallet) friendly octane level but the draw back is it is now to much camshaft that now feels soggy in power everywhere. It is now inefficient. It’s like giving away HP or allowing your competitor a free shot of NO2.

                Just the reverse will happen if you install a smaller cam. The smaller cam “EEE” is 10* smaller than the first. Then the dynamic psi goes up to 190.
                This is a problem again because now I take to feed the new high dynamic ratio is ether race fuel @ 3 times the price or impossible to get.

                Like I said, these are just numbers thrown out there and 10 psi is and isn’t a lot. It depends on many factors of the engine build and the rear of the car in what it is designed for.

                Adding head gasket thickness for a ratio Change In order to drop to a more friendly pump gas level can and normally does add in another issue. Detonation do to poor quench.

                I’ve run the Edelbrock head a long time and it works great in the performance arena when you have in the area of a .040 head gasket coupled with a reasonable sized cam. I wouldn’t want to run the piston to head clearance any more than .050 unless it is getting a turbo/super charger.
                 
              • rumblefish360

                rumblefish360 so close yet so far away

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                Oh! Just run the 1850 and enjoy it.
                 
              • Kendog 170

                Kendog 170 Member

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                Well I tried the dipstick vac check with valve covers,dist. vac, carb and manifold ports blocked. I got no vacuum reading and no pressure reading but did start getting some valve cover oil drip though gauge showed no pressure my guess is it was starting to build some. I may just register the car so I can drive it some and see if things get better or worse with after I dial in my distributor. Have you guys used these plates you can get at Mancinni's ? I bought one for my Big Block but currently am happy with how is performing to try it. FBO Mopar Distributor Limiter Plate