250 with aluminum head - initial tuning

[62Ranchero200]

Readjusted the valves this week - ended up tightening them about one flat more, and felt much more confident about the process than the first time (have never used adjustable rockers before).

Noticed that the mechanical fan neatly sheared off one of the tie wrap-type attachments for the electric fan, but no harm seems to have been done to the radiator. A noise that sounded like valve train tapping turned out to be the fan hitting a transmission cooler line fitting - one of the fan blades was slightly longer than the others. Trimmed the fan blade with a hacksaw. No harm seems to have been done to the trans cooler line fitting (it's metal, and the fan is plastic).

Set the idle mixture, which allowed the engine to idle a bit lower - about 1,000 RPM in park or neutral. At idle, there's about 12.5" of vacuum, more than I had with my old 200 and the Clay Smith 264/264/110 cam. At cruising RPM, have about 15" of vacuum, rising to about 20" on deceleration. Surprisingly with the 274/274/108 cam, the engine DOES idle in gear once it's warmed up (only have a manual choke at the moment). It idles very low and mean.

Plan to take it on my longest drive yet tonight, about a ten mile round trip.

Need to hook up the A/F ratio meter soon (already have it, the bung is already welded into the collector, and have an opening in the gauge cluster for it) and do some further tuning.

The lower radiator hose hangs down a little too far, have a shorter hose on backorder that should improve that some.

Thanks
Bob the Builder

 

[powerband]

Congrats' if you built the motor, initial start-up is a meaningful experience. concentrating on problem i] noise indicators [/i] and individual components heat cycling changes, it takes a good ride to appreciate the concert of new parts and careful assembly work.

my 250 61's initial startup slowly revealed DOA ignition module, carb problem and overheating needing remediation - after a short ride.

have fun

 

[MustangSix]

Bob,
Good job on getting it running.

It kind of worries me that you found one fan blade longer than the others. Are they all the same now? I've had fans disintegrate before - no fun! And any slight imbalance will kill the water pump earlier.

Keep us posted!

 

[62Ranchero200]

@MustangSix,

It was my own error that one fan blade was slightly longer than the others. The 250 sits so low in the chassis that initially, the fan was hitting the lower radiator hose. I trimmed the fan blades with a hacksaw to alleviate this issue. I've already ordered a 14" flex fan to replace the 16"-17" one I had to trim.

Thanks
Bob

 

[62Ranchero200]

Yesterday I installed an Autometer wideband A/F ratio meter; it was easy to install and worked great immediately. Posted some questions in the Hardcore forum about what are the optimum ratios for idle, cruise, part throttle acceleration, WOT. All I have gathered so far is that ~15.1 is a theoretically ideal mixture, and OK for idle or cruise, but that a richer mixture is better for part throttle acceleration and WOT.

What amazes me is that after a 45 minute Google search, I couldn't find any books or detailed web articles about how to use a wideband for tuning. For someone who's never done it, it can seem a bit intimidating.

I realize that the vast majority of cars on the road today are equipped with electronic fuel injection, so tuning probably involves altering the programming of the ECM (or whatever the current terminology is). Would love to find some kind of guide to tuning carbureted engines using a wideband: how to approach idle mixture, main jet, accelerator pump, and power valve tuning (I'm running a Holley 500 CFM 2 BBL). Could a guide to tuning a carbureted engine by reading the plugs, etc. be applied to wideband results?

If any of you have links to articles and especially to books, please share them.

Thanks
Bob

 

[xctasy]

They do, but lambda Wideband readings aren't everything. I've used CARCODE the ODBII downloads to from a base of ignition and air fuel, and don't mind using a bit of technology with a narrow band. I don't use wide bands as a tuning mechanism, but as a pyrometer to warn you. People here like wsa111 can get away with it, but I'm against sole use of the device because it removes trained sensitivity to poor drive-ability.

I favor what traditional "carburationists" call the
1.idle,
2.off idle,
3. progression/transition,
4.power circuit testing.

The last four are checked when you go to a mile marker, and copy off an LM-1 or CarCode or XLS/ Explorer air fuel down load , taking first gear from a standing stop, slowly accelerating up the rev range. Those systems allow you to replay poor air fuel matching. You then asses the quality of engine acceleration. The idea, suggested by Troy Patterson from SpeedTalk, http://speedtalk.com/forum/viewtopic.ph ... 0&start=30

is to see if the engine accelerates at a given rate on the off-idle circuit then picks up power when the main circuit comes in. In this case, you know the off-idle circuit is lean. If the engine looses power when the main circuit comes on you know it's lean and so on. This dude has a rather savage dislike of wide band a/f meters, but he is assessing the quality of performance in heavily saturated Pacific Grove California roads, where all the roads are hills and a mountain and traffic. Flat level streets, roads and highways don't exist.




First the engine has to run right in a day to day basis, then you do durability trails. The right O2 sensor reading is the one that works with you ignition settings. The LS Chevy engine runs the richest setting around, but counteracts the richness by having a very aggressive ignition ramp, and very wide 116/1175.5 cam lobe separation angles to look after emissions. In emissions engines, they like to look after quick catalyst light off long term protection of the catalyst; they use the richer air fuel ratios to avoid piston slap service problems, and crank, rod and bearing failure under detonation. The Chevy engine is a a high swirl engine, with intake valve mixture motion and SAE paddle wheel rotation figures equal to a hurricane alley cyclone. Modern engines air fuel is therefore firstly based on 50000 mile aged Federal Motor Vehicle Emission and CAFE compliance, then 300 hour WOT Durability figures, and then drive-ablity and lastly, that should meet the original performance requirements.

The Classic Inlines head is similar to the LS head, its best to set it up rich. When you lean it off the mixtures, it gives a good deal lot of extra power, but it then fails its wide open throttle 300 hour durability test in areas like exhaust valve, con-rod and bearing life.

Our best exemplar here is wsa111. He uses his Innvovate LM-1 O2 sensor and Sun distributor timing machine all the time. Problem is, you have to use the "brain in the head" drive-ability test first, then do a wide band sanity check second. I favor a test method used by Troy, since I'm not smart enough to get anywhere near what Bill can do. I'd guess most of us are the same.

I'd look at the richer side of the scale, and use a non transient drive as a litmus test for setup, then cross check with a wide band.


http://www.fordsix.com/forum/viewtopic.php?p=269276

https://www.fordsix.com/forum/viewtopic ... 58&start=0

viewtopic.php?f=3&t=19533

viewtopic.php?t=19141

viewtopic.php?f=5&t=65985

 

[wsa111]

Using the innovate wide band sniffer after the distributor is set up for your combination.
Cruising ratio at highway cruising i shoot for 14.5-14.7, WOT 12.5-13.1 A/F ratio. Again i install removable jets under the power valve-pvcr. I also install a richer jet on the front jet if the carb is mounted sideways. Liquid fuel runs back on acceleration.
On most engines i have to install a leaner idle jet. The stock 4412-500 Holley metering block has to be modified to do this.
Idle A/F 13.0-14.0 depends on engine components such as camshaft.
With the stock 4412 the transition mixture is normally too rich like 10.5-11.5 A/F ratio. I install a leaner idle jet & get the transition mixture closer to 13.5 area.
Sometimes i have to change the idle air bleed to achieve this, again your stock 4412 does not come with an adjustable idle air bleed.
To make a long story short the carb as received from Holley is way rich.
Hope that answers your question. Bill

 

[xctasy]

Ah, thanks wsa111. Knew you'd sort him out.

.....Surprisingly with the 274/274/108 cam, the engine DOES idle in gear once it's warmed up (only have a manual choke at the moment). It idles very low and mean. .......

Thanks
Bob the Builder

The 250 six isn't anywhere like the 200....the extra 50 cubes is another quarter of an engine breathing through the same head...even a head as brilliant as the Classic Inlines requires a LSA much tighter than the 200. Normally, a free-er breathing head makes a car more cammy. In American and Australian 200 and 250 Fords, they just compromised on one LSA angle. The advice you've been given on cam choice is very good.

Despite the sky high SAE 278 and 50 thou 228 duration figures, Gene's log head 250 is very sublime with that cam at a wider lobe separation angle. Doubting Toms
can deep six all doubt. I've seen this with other Ford engines like the 2.0 OHC Pinto verses the 1.6 European OHC, the 351C verses the 302C, the Boss 351C cam verses the Boss 302Windsor...all the short stroke versions of the same bigger engine with the same camshaft SAE and 50 thou figures have way more idle chop and camminess. I drove a 302 Boss Mustang a while back, and compared to my mates Boss 351 spec Falcon, it had a shaky idle and very rampant transition...on the cam like a crazy horse at 3900 rpm., while my mate Blairs XY 351C was all in by 2700 rpm, it had no choppy idle, and did 20 US mpg at 60 mph and 14 around town.

The small Pinto 1.6 was 25% smaller, and ran choppy with a Erson 134 that runs sooo smooth on a 2.0 Pinto.
The 351C in 4v or 2v form runs smooth with 295 degrees of hydraulic lifter on 109, while the 302C 2V and Boss 302 hardly idles with just 290 degrees
The bigger Ford engines of each are 25 to 17% bigger, and that's all it takes to calm down a rampant idle.


Back to finding air fuel nirvana guys.




viewtopic.php?f=1&t=70843&p=543797#p543797

Remember a 250 can take more cam than a similarly built 200 so I would go with more than the 264 cam IMHO. As an example, I am running the 278/110 clay smith cam from Mike and it idles nicely but makes nice power. With my log head I am seeing 170 hp at the wheels...who knows what it would be with the aluminum head and small 4 barrel carb.

 

[62Ranchero200]

Guys,

I really appreciate all of the help, especially the detailed tuning trips from xctasy and wsa111. Now that I have what should be a durable and powerful combination, I want to make the most of it by tuning. Trouble is, all I know of carb tuning are the absolute basics.

xctasy, the truth is, several people recommended the Clay Smith 278 solid cam, and I'm sure it would have been an excellent choice performance wise, but I shied away from the potential of having to adjust the valves often for a solid cam. So far it appears that the 274/274/108 hydraulic cam will be quite satisfactory.

wsa11, sending you a PM re: help with tuning.

Thanks all
Bob the Builder

 

[xctasy]

Ah, cool, the http://classicinlines.com/proddetail.as ... 274-HSP-08

Nice selection.

 

[62Ranchero200]

I adjusted the idle mixture screws to an average reading of 13.5 (fluctuating between 13 and 14) idling in gear at 750 RPM. After this adjustment, the engine idled at about 12.0 in park at 1100 RPM. While cruising, the engine runs at about 12.0. I haven't run the engine at WOT yet.

The Holley came with #73 jets; ordered a pair of #71 jets. They should have arrived by the time I return from my week's vacation next Saturday, and I should be able to change out the jets and test drive next Sunday.

Thanks
Bob

 

[62Ranchero200]

Greetings Ford Six Fans,

Just got back from Yellowstone - what a beautiful place!

Installed an electric choke on the Holley for cold starting. The choke has to be in the extreme lean position before the engine will start. The choke has a small vacuum take-off which tees into the line for the distributor vacuum advance, so now the vacuum advance is getting even less vacuum (it's on a ported vacuum source).

Also installed some #71 jets. Although Holley advertised that the carb came with #73 jets, it actually had #74 jets. Here are my A/F readings after I installed the #71 jets:

Idle in gear (about 700 RPM) : 13.5
Idle in park (about 1,100 RPM): 12.5

While cruising at a constant speed, the A/F ratio starts rich and gets leaner as the RPM increases:

1,500 RPM: 11.5
2,000 RPM: 12.5
3,000 RPM: 13.5
WOT: 11.0

Thanks
Bob the Builder

 

[wsa111]

Welcome back, hope you took some great photos. PM sent, Bill

 

[MustangSix]

Still looks a bit rich to me, Bob. Bill had good suggestions for what they should be.

I would just try changing the jets again to a 69 or even a 68 to get cruise where it needs to be. Leave the power valve alone for now.

Idle mixture should be tunable with just the mixture screws as long as the blades are closed and not yet uncovering the transition slots.

 

[wsa111]

Still looks a bit rich to me, Bob. Bill had good suggestions for what they should be.

I would just try changing the jets again to a 69 or even a 68 to get cruise where it needs to be. Leave the power valve alone for now.

Idle mixture should be tunable with just the mixture screws as long as the blades are closed and not yet uncovering the transition slots.

Jack, i'm going to lean the WOT with changeable jets below the power valve & also lean the idle jet & try a 70.
What needs to be done is get some more miles on the engine so i can see what the WOT is at 5K

 

[62Ranchero200]

I think the Holley 2300("500 CFM") is pretty much dialed in, with a lot of help from wsa111. He initially provided a QuickFuel metering block that included the following:

* Relocated and drilled the idle passages to allow the use of replacable idle jets
* Drilled the power valve channel restrictors (PVCRs) to allow the use of replaceable PVCR jets
* The stock #50 power valve (PV) was replaced with a #65
* The stock #74 main jets were replaced with #70 as the Holley was originally rich throughout the RPM range
* The stock .028" accelerator pump nozzle was replaced with a .031" for quicker throttle response

After a number of iterations of tuning the metering block, think the A/F ratios are pretty much where they need to be.

Next is a distributor recurve, and perhaps different spark plugs. Once the recurved distributor is in place, I will chassis dyno the Ranchero and also verify the A/F readings. Also included in future plans are subframe connectors.

Thanks
Bob

 

[62Ranchero200]

After driving the Ranchero to muffler, transmission and front end shops and to the local cruise-in several times, had about 500 miles on the engine this morning and the break-in period is officially over. Picked up some Joe Gibbs petroleum-based ZDDP oil and will change the oil some time next week. Will check the plugs while I'm at it and select a hotter plug if indicated. Machinist says I can probably tighten up the valve lash another flat on the adjusters.

Should receive my recurved distributor in 1 1/2 to 2 weeks and then can take the Ranchero to the chassis dyno.

Thanks
Bob

 

[Gene Fiore]

Looking forward to the dyno results!