Pond 510 Running Rich

[BigBlueOvalFan]

Hello Everyone,

I'm running a Pond 510 w/Stage II Keith Craft heads, a tunnel wedge w/2 Holly 600's (4160's).  My wide band O2 is giving me a reading of 8:1 under small load w/110 octane fuel.  I pulled the front carb which is my primary (using progressive linkage) and my jets are 64 which seem to be on the small side.  Before I make a bunch of mistakes and have to tear this thing apart 20 times, I figured you guys might give me some direction. I haven't looked at the power valve yet to check the number but will do so next.  If more info is needed, please let me know. 

I haven't checked my secondary (back) carb yet but would assume it is matched to the front. 

Any help would be great.

Thanks, Jim

[BigBlueOvalFan]

Small update;

The rear carb is also setup with 64 primary jets and both carbs have 8.5 power valves which is most likely my rich problem.

I'm going to swap out the power valves for 4.5 as I have about 10lbs vacuum at idle.

My next question would be; do the 64 jets in both carbs sound correct for the new power valve and should the carbs be staggered with different jets and power valves with a progressive linkage setup ?

Any help would be appreciated.

Thanks, Jim

[Barry_R]

Little steps first.
Power valves sound like a good place to start since you have ones that seem high for the application.
Can you monitor vacuum while running under that load & speed?  Cell phone video camera, cheap vacuum guage, duct tape, and a running commentary can help as a poor man's  datalogger so you can gather information and drive at the same time...

[My427stang]

Agree with Barry.

The jets are already a bit lean, most 850s usually run a 66, so I like the PV plan

As far as your choice on power valves though, I wouldn't go 4.5, that's likely too far the other way.  My guess would be 5.5 or 6.5 but to be sure, I would recreate the 8:1 and see what you are pulling for vacuum at that load with a gauge hanging in the car and delay the PV a bit.

Typically, when I see a guy go 1/2 of idle vacuum or so, he has to compensate by jetting up, then it goes fat later, although that is a safe technique, it isn't right. 

Also, realize that one of those could be bad, look for wet in the chamber behind it or test with vacuum.  Having it THAT rich, is generally more than just PV timing

Other things like float level or plugged or bunged up air bleeds can add to it.

Finally, if recently apart, metering surfaces on the body can warp and cross channel, but to me it sounds at this point like you may have a PV issue

[jayb]

I think I'd be suspicious of the O2 sensor reading.  8:1 is at the very bottom of the scale.  How does it read under full throttle acceleration, is that number reasonable?  While you are seeing 8:1 on the O2 sensor, are you getting black smoke out of the exhaust?  If you were really that rich, the engine ought to be stumbling, and you should be seeing a bunch of black smoke.

[Barry_R]

Great observation by Jay - I missed it.

My dyno O2 systems run a fat to lean calibration loop on startup - both sensor readings go to full rich and it's indeed 8:1, then the sweep to full lean at 16:1 before they fall into a normal reading range.  At a steady 8:1 you are more likely to be seeing bad data than anything really useful.

[BigBlueOvalFan]

Little steps first.
Power valves sound like a good place to start since you have ones that seem high for the application.
Can you monitor vacuum while running under that load & speed?  Cell phone video camera, cheap vacuum guage, duct tape, and a running commentary can help as a poor man's  datalogger so you can gather information and drive at the same time...

Barry,

I have a mechanical vacuum gauge and Innovate digital WB O2 that can download info in the car.  This was the first time out after a 7 year build and I was more interested in listening for rattles, etc.  The engine was dynoed by the builder and when I inquired as to how rich it was running, he stated that it probably fattened up because of the air cleaner.  I have my suspicions that they didn't really spend anytime dialing it in after seeing the 8.5 PV's and 64 jets.  I think they just ran the carbs that I purchased.

I'm going to try pulling the data off the O2 today and see what I get. 

[BigBlueOvalFan]

Agree with Barry.

The jets are already a bit lean, most 850s usually run a 66, so I like the PV plan

As far as your choice on power valves though, I wouldn't go 4.5, that's likely too far the other way.  My guess would be 5.5 or 6.5 but to be sure, I would recreate the 8:1 and see what you are pulling for vacuum at that load with a gauge hanging in the car and delay the PV a bit.

Typically, when I see a guy go 1/2 of idle vacuum or so, he has to compensate by jetting up, then it goes fat later, although that is a safe technique, it isn't right. 

Also, realize that one of those could be bad, look for wet in the chamber behind it or test with vacuum.  Having it THAT rich, is generally more than just PV timing

Other things like float level or plugged or bunged up air bleeds can add to it.

Finally, if recently apart, metering surfaces on the body can warp and cross channel, but to me it sounds at this point like you may have a PV issue

Thanks for the response,

I'm going to change the PV from 4.5 to the 5.5 per you suggestion and buy a couple 6.5's for back up.  I read the same thing you're talking about with going to low on the PV.

The carbs are new out of the box from Carl's Ford (the matched set of 600's for the Shelby 2x4 setup), so they've never been apart (besides me taking them apart last night).  I'll check the air bleeds and the re-set the float levels.  Any advice on how to set the float levels on the bench ?

Thanks, Jim

[BigBlueOvalFan]

I think I'd be suspicious of the O2 sensor reading.  8:1 is at the very bottom of the scale.  How does it read under full throttle acceleration, is that number reasonable?  While you are seeing 8:1 on the O2 sensor, are you getting black smoke out of the exhaust?  If you were really that rich, the engine ought to be stumbling, and you should be seeing a bunch of black smoke.

Jay,

The O2 is a digital Innovate 3844 MTX-L.  I'm going to see if I can download the info today from my short run.  This was the first time out with this car after a 7 year restoration and I was paying more attention to odd sounds, rattles, etc.  I also was a bit nervous about getting into it too hard in my neighborhood but I did rap the throttle to the floor once in 2nd gear as it was in good 15-20mph roll and it fell on it's face.  It was only a rap of the throttle and I didn't intend to stay in it, just wanted to see what it would do.  I don't really have a place to test the car nearby and would have to make a short burst on a fwy on-ramp for any full throttle info. I didn't look out the back to see if it was blowing dark smoke but when the throttle is rapped in the shop, it doesn't smoke at all.  It also doesn't stumble under light to moderate throttle. 

I only glanced at the O2 a couple times and could see it drop to the 9:1 to 8:1 under light/moderate load.  I only once gave it about 1/2 throttle but it was a short period and I was paying more attention to the road.  I'm changing the springs on the throttle and replacing the throttle rod with a billet type with those ball bearing ends as it currently feels like it binds.

Would you setup both carbs the same on this application with the progressive linkage setup I have ? I'm going to swap out the PV's for 5.5's and then give it some more testing so I can provide more info for you guys.  Would you recommend re-sizing the jets for the new PV, or just run the 64's.  I know this is the beginning of pulling these carbs on/off many times and expect that timing and other factors will come into play, I just want to reduce the nasty fumes a bit and get it somewhat close for now.

I apologize to all you guys for not having more info and will re-test once I change the PV and see what I can download off the O2. 

Thanks, Jim

[Barry_R]

The reproduction carbs are nice enough parts, and are the right pieces for a restoration application.  That said, they tend to be very rich on the dyno - knowing what they are I would not be afraid to pull several jet sizes out - maybe pull four and see how it responds.  I have run those all the way down into the 57-59 range with good data....

[BigBlueOvalFan]

The reproduction carbs are nice enough parts, and are the right pieces for a restoration application.  That said, they tend to be very rich on the dyno - knowing what they are I would not be afraid to pull several jet sizes out - maybe pull four and see how it responds.  I have run those all the way down into the 57-59 range with good data....

Thanks Barry,

Would you set both of them up the same with the progressive linkage setup ?  And do you think I should drop the jets to say 60's or 62's with the PV change this time or see how it reacts to just the new PV ?

I'm running a Comp Hyd roller 635/633 lift, 248/252 dur w/108 center, 112 lobe separation.  You've probably built my similar setup plenty of times.  I can provide more info if needed.

[BigBlueOvalFan]

I was also wondering if you guys have any recommendation with squirter size ?  I'm currently running the standard type w/o the nozzle and they're 31's on both carbs.  I plan to purchase the nozzle type squirters and was wondering if I should go up or down in size or keep them the same ?

[cjshaker]

I would not go changing things until you're sure the O2 sensor is giving a correct reading, as Jay said. At that level of richness (given a correct reading), the engine should not be running good. Are your exhaust pipes showing heavy black soot? Are the plugs showing black soot? If the exhaust is not showing heavy soot inside the tailpipes, then I'd think you're getting faulty info. The black smoke out the exhaust upon hard acceleration should be obvious looking in the rear mirror if it really is that rich. Have someone follow you and watch if you can't watch in the mirror.

Like Barry said, those carbs tend to be on the rich side out of the box, but with such a big cubic inch displacement they may not be as bad as is normally found. And yes, I'd leave the secondary carb the same as the primary. Changing the back one will lead to issues under hard throttle once things are dialed in.

[Ford428CJ]

Have you pulled the spark plugs to confirm this??? Lets see the spark plugs. This will be the true indicator on whats going on here... Just my thoughts....

[sixty9cobra]

I am no expert but you better not be using 110 leaded gas it will kill the O2 sensor in no time!