Starting to understand why building engines may be best left to the professional

[Yellow Truck]

Ross - I have printed out the post you wrote. Thank you for such a thoughtful response. I also acknowledge a few others including Drew who have given careful direction.

Before I go further - on the timing issue what I have noticed with the old Ford/Petronix combo is that the timing changes from one day to the next, not while I'm driving it. I'll see it at 20 when I start it, 20 when I park it, and a couple of days later I'll check it again and it will be at 16 or 24. I've been ignoring it of late, but getting a bad MSD distributor was a set back.

On to your note:

I had the carb set up from the factory with the jets taken down two sizes to adjust for the 3,500 foot altitude here in Calgary. It was very rich and fouled plugs quickly. I also had the primaries open too much so I closed them down - the pictures show where the were after I adjusted them:

Primaries
Primaries as adjusted by Fred Snoyd, on Flickr

Secondaries
Secondaries by Fred Snoyd, on Flickr

I had the carb adjusted by a local shop (I didn't want to but this was when my wife was having her bypass surgery) - they told me they took the jets down from 76 to 72 and 78 to 74, the pump down to a 3.5, and the powervalve down to a 3.5. It now doesn't foul plugs and the O2 readings were with these settings. It idles around 1,000 right now. I did NOT yet do what I was told to do - bend the secondary linkage to make sure the secondary snaps shut. I will. I also have not touched the IFR. I know I have more carb work to do. I decided to take questions about the cam timing on first, and my friend who helped me is relieved because he was sure he had done it according to the instructions. Since I hadn't done it before I didn't have as good a recollection of how we did it.

Initial timing has been up around 18 to 20 based on the marks on the balancer, and I have no reason to think they are bad but will confirm with the piston stop before I put the plugs back in. I did set it by ear and then checked it, and it was happy (higher idle and vacuum) around 22 according to the marks on my balancer. There is no rev limiter.

I have a 1 inch Super Soaker phenolic resin spacer on there, and my fuel is routed up the passenger side of the firewall and into the carb away from heat. Used to have vapour lock issues with the 410 so I re-routed it away from all the heat. I'm running an old Street Dominator intake and seem to have good clearance.

I see you suggest that we will have to reconsider initial timing and carb once the cam is advanced. I'm even more inclined to think it makes sense to do it now since all the adjustments to the carb will need to be done again.

Thanks for your advice, now I have to figure out how to change a valve spring with the heads on. That is ok, learning is good.

[My427stang]

So that looks good, assuming you didn't have to change the idle screw setting much after install.

As far as higher elevation and jet change, I just cant see two sizes of jets fouling plugs.  However, if cylinder fill is that much worse, advancing you cam will help more than someone at higher air pressure

[Yellow Truck]

Ross, I'm not finished my reply - was having trouble using Flickr to add pics so am modifying that post. BTW my name is NOT Fred Snoyd. I use that name for annoying websites that demand a name. My real name is Paul.

[My427stang]

Ross, I'm not finished my reply - was having trouble using Flickr to add pics so am modifying that post. BTW my name is NOT Fred Snoyd. I use that name for annoying websites that demand a name. My real name is Paul.

LOL no worries Paul, I'll call you whatever you want

My opinion is that the advanced cam will help how it runs in general, additionally, I think your person who set up the carb didn't help you but we can chase that later.  FYI, I think you are a PV swap away from that carb being spot on given your numbers.

One thing that could be good at this point, is in one response, list what you are unhappy with right now.  Then before I spend your time or money, we'll be very clear on what the truck is doing and how far to go with it.

[Drew Pojedinec]

Fred,   
If you need to get the idle lower, you can still shut the secondaries a lil bit.  I'd have that not showing the slot (or barely) before messing with the feed restrictions (well, other than lowering the ifr, but that might be beyond the scope of what you wanna do).
Ross mentions the PV and is dead on, with your engine/cam you shouldn't need anything lower than a 6.5, but this is tested cruisng, plus you have a wideband so it'll be obvious when the valve opens as you'll notice the a/f go super rich.
I've also noticed with the emulsion on those carbs that they go super rich when the mains come online, only leaning out as rpms gain.  Probably looks just peachy on a dyno, but for a street car it's sucky unless you just stab the throttle constantly.

Is your intake vac still really low?
Where are your idle mixture screws?  (as far as how many out)
You know that you don't *need* to have all four the same, sometimes 3/4 turn out on the primaries and 1/3 out on the secondaries is the trick, sometimes ya gotta just play with it all to see what they like.

Course it's still a big double pumper with a 50cc pump, so is what it is.

[Yellow Truck]

I'll put my full set of conditions down in one place, but a couple of quick comments -

The jetting down two sizes for altitude was just QFTs standard recommended adjustment. It should have reduced the rich condition but was still way to rich. I don't think the shop that did the carb adjustments did a great job, but they got it so I'm not fouling plugs every 10 miles, so I can drive it a bit.

Even with the timing advanced I'm still seeing no better than 8 inches. One thing about vacuum that I've been thinking about is the fact that you can't create more vacuum in space, so clearly at 3,500 feet I'll see LESS vacuum than the same mill at sea level. If I ever move to Vancouver Island I may have to back the cam off, assuming I advance it.

BTW - I bought the package from Barry and he said he can't believe that cam will interfere with the piston at 4 degrees of advance. I think I'll pull the timing cover today and see if I can get the crank spacer off. I will put it back together and run to see how the cam change affects it before I put in a new distributor or adjust the carb.

[My427stang]

Paul, First and most important.  I like your plan, advance the cam and it'll gain vacuum.  Ignition timing alone will gain some, but once you get to the point you are, you have to change valve events in relation to piston movement with either a smaller cam, or advancing a larger one.  My guess is, with 4 degrees advance from where you are now, you will get to 10-ish.

Second - You understand vacuum perfectly, higher elevation, less atmospheric pressure.  Don't worry about it being too advanced going 4 degrees forward from where you are, your cam would be happy at sea level in the advanced position, that's what DCR calculation can tell you.  At sea level, using the combos I build, 8.33 is about perfect with alum heads, you are in the mid 7's.  DCR is only a tool, one of many inputs that guys like me use, but yours is retarded for use and going 4 degrees forward (in your specific combo) will never have to be readjusted for lower elevation.  I am only saying this part to make you feel better about your decision.

Third - I understand that the carb setup may have been one of the things that seemed to go right, but it's really not how you want to set up a street carb.  I am only saying it because you sort of justified that it made things better.  Fact is, there is no way that your jet and power valve change fixed a flooded engine unless the original power valve was leaking/ruptured.  I believe you 100% that it's better after the change, but the 3.5 PV is wrong for you.  It does make sense if it replaced a bad PV, but a good 6.5 or 5.5 will likely let the truck run better, especially under load and won't go lean too early as the truck starts building a little vacuum.   Again, the only way the changes they made could stop a flooded engine is if the PV was ruptured and flooding the well behind it.  I promise. It doesn't need to be fixed right away, but, to dial it in right, you'll address it later.

I am going to hold back until you get a chance to do a consolidated list, I just want to make sure I am offering a the right advice and sort of lost the bubble.  Regardless, that engine will be happier with the cam +4 from what it is.

[Yellow Truck]

It may be that the PV was ruptured. Early on we had some good backfires. The QFT support desk insisted that it would rupture, but I'm fine with putting a new one in. They put in a PV I had bought when I was getting a vacuum of 6 at best. I completely believe you and Drew that the carb is more pats wrong than right at the moment. I will find out what the IFR size is that came on the carb - it isn't included in their spec - and will consider changing it when I know.

I'm in the middle of the timing set removal - will need to pick up a gear puller tomorrow to get the crank gear off. I also will have to drop the oil pan since I broke a piece of a scraper and it disappeared down towards the rear of the pan. It is also collecting a lot of crap from scraping the gasket off.

It is a pain to drop the pan since it is a 4WD with lots of stuff in the way, but if I do I can correct one bone head move I made by not installing the oil pump drive shaft from the bottom. Might as well get all this done at once. Need to pick up a retainer clip for the pump drive and then putting in and pulling distributors (something I've done all to much of) won't be such a challenge.

[Drew Pojedinec]

It may be that the PV was ruptured. Early on we had some good backfires.

Seems harder to blow them on modern carbs than it used to be prior to the lil baseplate checkball.

I will find out what the IFR size is that came on the carb - it isn't included in their spec - and will consider changing it when I know.

For some reason I thought the ifr on the one of those I played with was .035
You got other stuff first as Mr Ross says.

It is a pain to drop the pan since it is a 4WD with lots of stuff in the way, but if I do I can correct one bone head move I made by not installing the oil pump drive shaft from the bottom.

Man that sucks.... but I gotta say, I've dropped the driveshaft in the pan before and that sucks even more

[Yellow Truck]

Drew - not sure how you get a driveshaft in an oil pan, but it sounds more exciting than a little piece of metal.

I bought the 3.5 because I was getting less than 6 inches of vacuum initially and figured the powervalve was probably open at idle - certainly at that time I could screw the mixture screws in until they were fully closed and it didn't make a difference so I assumed I was pulling fuel from somewhere.

[My427stang]

Drew - not sure how you get a driveshaft in an oil pan, but it sounds more exciting than a little piece of metal.

I bought the 3.5 because I was getting less than 6 inches of vacuum initially and figured the powervalve was probably open at idle - certainly at that time I could screw the mixture screws in until they were fully closed and it didn't make a difference so I assumed I was pulling fuel from somewhere.

*oil pump driveshaft   

Paul - Holley's recommendation is 1/2 of idle vacuum, but to be honest that only works well in a narrow range of vehicles that pull between 10-15 inches of vacuum.  When it pulls a lot of vacuum or not much, the recommendation is generally wrong.

If you drove that truck with a vacuum gauge, you'd likely find that it has a lot more than 6 inches during cruise, and doesn't drop below 3.5 unless you really were hammering it, which means it's closed and not adding fuel

Also, need to clarify the "fuel at idle" comment.   A properly working PV cannot, will not, is unable to provide fuel at idle, even if wide open.

Think of the PV as a spring loaded extra main jet, not as a valve that dumps fuel into the engine. The way it works is, when your throttle plates are open, air rushes by the boosters and pulls fuel from the main jet, when vacuum drops past the PV value, the PV opens and adds extra fuel to that circuit (like a bigger main jet)  it does NOT inject it on it's own.

So, when at idle, the throttle plates are closed, no air is rushing by the boosters, so no main jet fuel is being supplied, and if no main jet fuel is being supplied, even if the PV is open, no fuel goes to the engine

In your case, the PV was likely ruptured, so BEHIND the PV is a vacuum well.  When it ruptures, fuel just runs into the engine and will flood like crazy.  That undoubtedly was the issue with the flooding, not the PV value and not the PV being open at idle, it just doesn't work that way.  So yes it was due to the PV, but not the reason you just stated.

Also, it is very easy to blow a PV, less so with the protection, but it doesn't take much, and if that little ball and spring sticks, or gets hit hard enough, they go away quickly.

One last thing, as a fellow 4x4 owner, be happy you can pull the pan, you wouldn't be able to in a 2WD 

[cjshaker]

One last thing, as a fellow 4x4 owner, be happy you can pull the pan, you wouldn't be able to in a 2WD 

True statement. I wish all of Fords trucks were designed in the front like my '68 Highboy is. Easy access to the pan!

[Drew Pojedinec]

Yup.  if you drive like a sane person you'll never even use the power valve.  For testing I've plugged it in order to get the perfect jet size without enrichment.

Here a cool picture (plus I'm trying out the photos on site)

[Yellow Truck]

Yup.  if you drive like a sane person you'll never even use the power valve.  For testing I've plugged it in order to get the perfect jet size without enrichment.

Here a cool picture (plus I'm trying out the photos on site)

Why would I build a 445 if driving like a sane person was my goal? In any case I will pick up a new PV and put it in when I take of the carb next.

[comet2]

i have to chime in on advancing cam timing i agree 100 percent on my 390 i went from 106 icl to 102 icl 160 psi cylinder pressure to 185 and gained 3 or 4 inches of vacuum ! runs much better now . on the 3.5 pv is too late  if you drive with vacuum gage attached you will notice you have to get in the throttle abit before you need anymore enrichment you want to start opening the power valve in anticipation of a lean condition not after it occurs! but dont dwell on this until the other stuff is sorted