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A 521 in Massachusetts


Crashtd420

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Well oddly enough the new plugs show the engine running a little leaner than before....

I'm gonna swap out my o2 sensor later just because I have another one and the readings on the gauge have been a little wierd.... 

I also changed the idle jets to add a little more fuel at idle and the transition ... going to check them again when I get home and see if anything looks better...

Might go up on the main one step next,  I'd rather be rich and have to lean it out a little than cause any damage to the engine.....

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Got home and had a look at the plugs, getting better.... so I decided to have a look at my o2 sensor...

Ya.... that's a bit dirty..  

 

20201014-160550.jpg

 

I had a new one on hand so I swapped it in and now my air/fuel gauge is pretty stable and showing good numbers.... I still think I have an exhaust leak but I suspect its further back than I had thought and doesn't seem to be effecting the 02 sensor .. 

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14 hours ago, datzenmike said:

If you mixture is good and the heat range correct the plugs are self cleaning. Don't wire brush the O2 I think there are sprays for removing carbon. Always good to have a spare

The mixture was good before which seemed wierd to me that it would act a little lean with just the plug change... maybe it has something to due with adding the pcv system? All I know is it seems like the colder plug  is letting me add some fuel which the truck seems to be liking...

I had a solid 13 on the gauge going to work this morning,  dropped to around 12 under heavy throttle getting on the highway.... 

I'm gonna drive it like this and see how its acting.... atleast my mind Is at ease with a properly functioning gauge.. 

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33 minutes ago, mainer311 said:

Colder temps in the morning. Denser air. Just a guess.

I know engines usually like cooler air but I dont think that's messing with my air/fuel readings.... I got the same readings around town yesterday afternoon....

Probably should have fixed my o2 sensor first before messing with things.. 

I can always go backwards if I need to but its actually running a little better... 

 

 

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Cooler thicker air will draw in more fuel so it averages out. Carburetors are amazing. However hotter air and hotter plugs do also run closer to auto ignition like a diesel and will be close to pinging and a loss of power.

 

While 14.7 is a prefect AFR it's a bell curve with not that much change from 13.7 to 15.7 as far are mileage and power. Low 13s under load is fine even high 12s. Hell my R-1s started out with 9.6 under load. I don't think the AF meter went lower. I got it to run 14.7 at about 40MPH cruise and low 14s on the highway. I think it will hit the 12s when really revved out.

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https://eldridgeusa.com/blog/air-density-impacts-on-fan-performance-part-one-what-affects-air-density/

Temperature

Increasing temperature causes most materials to expand.  Air acts the same way.  As the air temperature increases, the molecules in the air are excited by the additional energy and they move further apart.  Pilots know that when the temperature increases, the air is less dense and that it requires a greater distance to generate the lift required to take off. 

To determine the impact of higher temperature on air density, this time we will keep the Standard Air conditions the same except we will increase temperature from 70º F to 80º F.  At the temperature of 80º F, the air density is .0735 lbs/ft3 which is 2% less than Standard Air density.  The table below, from engineersedge.com, shows that increasing temperature doesn’t begin to make a significant change in the air density until it gets above 100º F.   

Screen-Shot-2019-07-22-at-1.10.09-PM.png

https://www.grc.nasa.gov/www/k-12/airplane/density.html

 

 

Cooler air is denser, has more mass at the same pressure.There's more of it. More air through the same venturi at the same pressure is going to have to go faster. If going faster it will increase it's vacuum effect at the venturi and draw in more fuel. Under hood temperatures can go well above boiling point even though ambient temperatures are say 60F. That could be 150F difference in temperatures. It's not a huge density increase, but simply put, cooler air is more air and gas and that makes more power.   

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Yeah, I understand air density, but colder air doesn’t “pull” more fuel in with it. It does in a fuel injected car because the IAT sensor tells the ECU it needs more fuel for stoich. In a carbed car, you need to rejet for extreme climate changes.


You’re getting your thermodynamics wrong. Suction through the Venturi comes from unit of volume. Denser air has more molecules per unit volume, but the volume doesn’t change, since your pistons can only pull in so many cc’s. Having more molecules of air per unit volume ends up in the lean condition. 
 

 

Edited by mainer311
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I seem to remember reading that what I said was the case. It's true of airplane lift on the wings. Denser (colder) has more take off lift at the same speed than warmer.

 

But also true that altitude (thinner) air runs richer than sea level.

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On 10/14/2020 at 3:52 PM, Crashtd420 said:

Got home and had a look at the plugs, getting better.... so I decided to have a look at my o2 sensor...

Ya.... that's a bit dirty..  

 

20201014-160550.jpg

 

I had a new one on hand so I swapped it in and now my air/fuel gauge is pretty stable and showing good numbers.... I still think I have an exhaust leak but I suspect its further back than I had thought and doesn't seem to be effecting the 02 sensor .. 

Hat to be that guy, but it seems that the O2 sensor and gauge did not help as they were intended. Seems like they sent you off on a fool's errand.

 

I've always felt that tuning for the street is done once, maybe seasonally, but mostly just once, and then you leave it and move on.

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1 hour ago, Stoffregen Motorsports said:

Hat to be that guy, but it seems that the O2 sensor and gauge did not help as they were intended. Seems like they sent you off on a fool's errand.

 

I've always felt that tuning for the street is done once, maybe seasonally, but mostly just once, and then you leave it and move on.

I basically have left it alone for a while now.... the visual check of plugs have always been matching the gauge readings... which is why I've ignored my inaccurate gauge for a while now....

 

I have always had a few lingering tuning issues which was why I was trying a colder plug.... the new plugs suggested I was running a bit leaner than before but I honestly dont get why that is... 

 

The only real change after that check was one step richer on the idle jet just to add a little more fuel during light throttle, just incase I was lean... the increase did show on the plugs and the color to me looked better...

So far i think that small change has helped some....

I made a few 5500 rpm pulls and it felt good,  I have had a couple times where doing that upsets things.... 

 

Honestly I'm just guessing at alot of this... this is why I keep spare plugs and jets with me in the truck... I can always undo something on the fly if needed...

 

Atleast now the gauge is working ....

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I also moved all the parts into the garage for the winter project.. .

 

20201018-154705.jpg

 

Getting the axles ready for disk brake conversion and the housing ready for the 5link.....

 

I think i need a press to go any further with the axles ....

20201018-161213.jpg

 

I'd like to replace the inner and outer seals and put new bearings in while I have it all apart.....

 

Of course even the seals are being a pain in the ass....

 

20201018-161230.jpg

Edited by Crashtd420
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Old bearings and retaining sleeves can be removed w/o a press and bearing splitter. Pull the cage off of the bearing and let the rollers fall off, then slot the inner race with a cutoff wheel and use a chisel to split it. The same can be done with the retaining sleeve. Sometimes the new bearings can be installed by sliding a pipe down over the axle shaft and letting the weight of the assembly hammer them on (against the face of the inner race, obviously).

 

I know Harbor Freight is crap, but I have their smaller hydraulic press, and if you shim it a little bit and set it up correctly, it actually works really well. I put mine on locking casters, and roll it out of the way when I'm not using it.

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10 minutes ago, mainer311 said:

Old bearings and retaining sleeves can be removed w/o a press and bearing splitter. Pull the cage off of the bearing and let the rollers fall off, then slot the inner race with a cutoff wheel and use a chisel to split it. The same can be done with the retaining sleeve. Sometimes the new bearings can be installed by sliding a pipe down over the axle shaft and letting the weight of the assembly hammer them on (against the face of the inner race, obviously).

 

I know Harbor Freight is crap, but I have their smaller hydraulic press, and if you shim it a little bit and set it up correctly, it actually works really well. I put mine on locking casters, and roll it out of the way when I'm not using 

I have a local shop that usually treats me good with tasks like this.... 

 

I'll try messing around with it like you suggested, worse case I just hand them a little more of a mess.... 

 

The thing is to do the disk conversion I believe you need to remove the hub from the backing plate also...

 

Again i probably can do with a cutoff wheel and chisle but might just be easier to pay for it to be disassembled....

I'm sure I could put it all together but not sure I really wanna waste the time struggling with disassembly....

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I have a tool I made for Toyota housings, which is an old axle housing that I cut one axle tube off and welded some angle on at the right height for use in the press. It is still a pita to remove the bearings. Even with the tool and the press, the chisel method is almost easier.

 

Looks like some floor to ceiling shelving would benefit you greatly. You could build a work bench into it so you don't lose space.

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1 hour ago, Stoffregen Motorsports said:

 

Looks like some floor to ceiling shelving would benefit you greatly. You could build a work bench into it so you don't lose space.

 

I have that on one wall, full of chemicals and parts.... 

20201009-163411.jpg

 

I have shelves above the bench with the drill press, the one with the angled legs and jacks underneath is my work bench now.... 

I could probably do another rack on the back wall behind the trailer.... right now theres just a table with all my shit pilled up on it.... I would just need to leave an opening for my ac... there is actually a window back there behind the boxes with an ac in it....

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Next time my wife tells me I have too much stuff, I'm showing her this picture. 

2 hours ago, Crashtd420 said:

The thing is to do the disk conversion I believe you need to remove the hub from the backing plate also...

 

Yes indeed, but, not a bad idea to do bearings and seals anyway. Almost fun refreshing stuff while you're there. 

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27 minutes ago, mainer311 said:

Next time my wife tells me I have too much stuff, I'm showing her this picture. 

 

Yes indeed, but, not a bad idea to do bearings and seals anyway. Almost fun refreshing stuff while you're there. 

The sad part is I threw a shit load of stuff out already.... 

 

I skipped the seals on the differential i am running and I'm pretty sure its leaking, i didnt wanna make that same mistake.... luckily I had a spare assembly to work with.... 

 

I'll at least be driving the truck till Thanksgiving... I plan to pull the bed off that weekend,  so not sure how much I'll be driving it after that till after winter is over.... 

 

I know I'll be driving it without the bed attached because it won't go back on till its stripped,  rust proofed and repainted , but I'm not sure if its legal or not....

I might have to make temporary fenders or mount some mud flaps atleast....

 

Edited by Crashtd420
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