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I've got a rich bog WOT off idle. Holley can't figure it out..

447 FE, 11:1 Comp, Comp 308R solid roller, MSD Pro Billet with 6AL. Motor only has about 500 miles on it.

1000 HP with annular boosters, upside down black front and red rear in 2, 52 shooters right now. 50cc pumps. 3.5 PV's. transfer slot's good. stock jetting.

idles at 700 RPM. 6" vacuum, 18 deg at idle 36 deg at 2500. 3600rpm stall converter, 4:11 gears.

Issue: when you go WOT from a stand still it will rev up to about 2k then stand still, some times it will clean up some times not. also will do this during a brake stand, will not spin tires on pavement. It pukes black smoke when it does this. If its on dusty pavement it wont bog and just blow the tires off. Ive tried all the cams and shooters, any less than a 37 and it will backfire through the carb. Going up in shooter with a front heavy cam provided the best results but far from great, right now with an upside down black and a 52 shooter has the least bog. Timing changes didn't do anything positive. tried higher idle, didn't change anything. Tried idle mix screws, no positive changes.

If you are moving more than 5-10 mph and hammer the throttle it will blow the tires off.

I think the boosters are coming in before the pump shot it done causing this, but im not sure how to fix it. this is my plan and my ideas:

1- I will be replacing both 50cc pumps with 30cc to see if it changes anything, also changing the secondary to the same as the front.

2- custom grind a carb cam to the profile i need

3- change the air bleeds to move the fuel curve.

Any ideas would be greatly appreciated.
 

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I think it's in the timing, I think you need all your timing in by 2100 rpm with the cam you have. I would try locking the timing at 36° and see if it would start, if not put a start retard on it and that should do it.
 

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Thanks! I will give it a try, I can throw the light springs in it to have it all in by 1600 or so. If it’s better than I’ll lock it out.

I tried lengthening the advance thinking it might be detonating but didn’t change.
 

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I've got a rich bog WOT off idle. Holley can't figure it out..

447 FE, 11:1 Comp, Comp 308R solid roller, MSD Pro Billet with 6AL. Motor only has about 500 miles on it.

1000 HP with annular boosters, upside down black front and red rear in 2, 52 shooters right now. 50cc pumps. 3.5 PV's. transfer slot's good. stock jetting.

idles at 700 RPM. 6" vacuum, 18 deg at idle 36 deg at 2500. 3600rpm stall converter, 4:11 gears.

Issue: when you go WOT from a stand still it will rev up to about 2k then stand still, some times it will clean up some times not. also will do this during a brake stand, will not spin tires on pavement. It pukes black smoke when it does this. If its on dusty pavement it wont bog and just blow the tires off. Ive tried all the cams and shooters, any less than a 37 and it will backfire through the carb. Going up in shooter with a front heavy cam provided the best results but far from great, right now with an upside down black and a 52 shooter has the least bog. Timing changes didn't do anything positive. tried higher idle, didn't change anything. Tried idle mix screws, no positive changes.

If you are moving more than 5-10 mph and hammer the throttle it will blow the tires off.

I think the boosters are coming in before the pump shot it done causing this, but im not sure how to fix it. this is my plan and my ideas:

1- I will be replacing both 50cc pumps with 30cc to see if it changes anything, also changing the secondary to the same as the front.

2- custom grind a carb cam to the profile i need

3- change the air bleeds to move the fuel curve.

Any ideas would be greatly appreciated.
First, I think 18 initial is plenty, although little more is a little better to bring up idle vacuum, also, if your converter allows it, don't be afraid to let it idle a little higher too. That's a big cam. Are you running vacuum advance? If yes, make sure you are setting initial with it unhooked, and if the vac advance port is alive at idle, may want to consider running manifold vacuum to the advance. I generally do NOT do that, but in your case, it could help. If you are mechanical advance only, no issues, but I want to make sure that you aren't at 18 with vac advance, and when you drop the hammer it falls out to something much lower

Second, I think you are bathing that motor in fuel, in fact, it's not good for it. I have experience with the 1000 Holley and I generally set them up with 30 cc pumps and .028-.031 shooters. Often I will use a blue cam on the front to get a low vacuum motor to hit a little harder as well, but even that is rare

Next, I think your PV is too tight, so you douse it heavy and fast with your big pumps and shooters, then it has to get below 3.5 inches of vacuum before it gets fuel again, so it goes lean with dirty plugs. I would be running 5.5 PVs and only if it was rich at part throttle cruise would I drop to a 4.5 and even then, only on the primary. In fact, I'd likely go 5.5 primary, back to stock jetting with 84s and if your version has a rear PV, you could plug it and go 90s out back, but not required. it just helps during hard launches because the PV can become uncovered easily

Finally, don't expect that 80513 HP to behave perfectly even after you get it back. We call those "high IFR" metering blocks, and they can be a pain in the butt. Somehow, with the IFR up above float level, they can be sloppy and cause transition issues and odd behavior when crusing. This isn't your problem yet, but may be after you get it dialed in. What I do then is get an early primary metering block off an old 600, drill all the orifices to match the 80513, but with the lower IFR block they clean right up. Again, not your issue, but come back if it gets fussy driving easy after you fix this

Last comment, always good to check every plug and every plug wire, especially the ends, to make sure you don't have some secondary issue, check firing order, etc. Just good housekeeping as you troubleshoot. Hope this helps
 

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One last comment.....this is a little milder than yours, but this is an 80513 on my 489 with 3.70 gears, 28 inch tall tires. It is set up exactly as I discussed before. After this, it went on my 445 truck engine and behaved about the same :)

https://youtu.be/QcUCi_AxjqQ
 

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MY427stang is always an excellent resource for all things FE. It pays to listen to his advice.

I'm going to add a couple things. A 308R is a solid roller race cam. For these to adequately oil the lifters, the idle needs to be set up to around 1,100 rpm, else there isn't enough splash lube. 700 rpm and 6 in of vacuum is way down on the low side.

For a cam that large, locked timing is NOT a bad thing. Only issue is starting when hot, as that much advance will fight the engine turning over. Many who do locked out timing put their ignition on a toggle switch. They will get the car cranking fast without the ignition on, then switch it on, and it fires right up. If you don't mind this step, locked timing might help provide the response you are looking for.
 

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Thanks for the suggestions guys!

I haven't had much time to tinker with the car but this is what I have done so far. I also talked to MSD and they suggested I might not have enough spark and to upgrade the coil.

I only have mechanical advance. I haven't had any issues at cruising speeds, purr's along quite nice. I do have the 80514, same as the 13 but with annular boosters.

- I installed 30cc pumps front and back, running red cams and 37 shooters front and back. This provided the best response in park before I swapped the coil.
- installed MSD HVC 2 coil
-Checked transition slot's, front and back are around .050 open but I managed to get my idle to around 1100 out of gear 950 in gear. Any more and I open the transition slots to much.

So far the coil has made a huge difference on how the car performs, it will brake the tires loose on good pavement and will do a burn out without hesitation.

I did notice if I let the car take off without fully opening the secondary's it wont bog out. But if I go full open the car will rich bog for a couple seconds still. Its way better than before.

I will try to reduce the shooters but when I tried before to go less than 37 it would pop through the carb. I only have 6.5, 3.5 and 2.5 PV's Ill try and grab some 4.5 and 5.5 to try out.

This weekend I will changes the springs out in the distributor to come in quicker and see if it makes a difference. Since the coil has made the most drastic change I will keep pursuing the ignition system first.
 

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This weekend I will changes the springs out in the distributor to come in quicker and see if it makes a difference. Since the coil has made the most drastic change I will keep pursuing the ignition system first.
For that much cam, you need to use the lightest springs and install the bushing for the LEAST mechanical advance. This will allow you to have more initial, which will help with response.

To check ignition timing, you should not be using initial numbers, but check TOTAL timing with the engine revved up and the timing fully advanced. Ross (my427stang) should be able to give you a good idea of what the total timing should be with your particular heads on an FE... but it will likely be around 36 degrees total.

Good Luck
 

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I will try the lighter springs next. I do have timing at 18 initial and 36 total, its all in right around 2350 rpm. I adjust for total every time I check/change timing then see what the idle timing is coming in at. Im using the "18 deg/black" bushing (smallest I have).
 

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I will try the lighter springs next. I do have timing at 18 initial and 36 total, its all in right around 2350 rpm. I adjust for total every time I check/change timing then see what the idle timing is coming in at. Im using the "18 deg/black" bushing (smallest I have).
I believe the largest bushings provide the least mechanical advance... and allow you to run more initial.
 

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Just to reiterate, you are not going to get there with timing. 2 sets of 50cc pumps with 50+ squirters and a tight PV is going to cause a mess and likely washing your cylinders. I would put it back to stock ASAP before you wash the cylinders so badly that you have to rebuild it

Another question though, which heads and did you measure everything to calculate compression?

After you get the carb right, you may need more total depending on the piston/chamber/gasket combo, which will give you a little more initial to help vacuum. Almost any FE likes 38-40 total unless you have a very tight quench and good chamber. Additionally, Edelbrock heads usually come in big, and often unless you square deck to 10.150 or 10.155 most 4.25 strokers are a bit below deck, add a common head gasket and you could be much lower than you think
 

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He said a few posts back that he had put 30 cc pumps on it.
Thanks, sorry I missed it.

Nice work, you'll get there

The PV is your next step, and if you are out of the transition slot, you can run as loose as a 6.5. Holley's 1/2 idle only works at higher vacuum readings. If you have throttle blades set right, PV fuel can't get anywhere at idle, it takes airflow over the boosters.

Think of it this way, accel pumps are battle axe ways to give fuel, jets are precise, PV restrictors are also precise. That battle axe is good for one blow and then something has to take over, the boosters, fed by the mains and PV channel restrictors

You stomp it, the battle axe jams some fuel in there because there is no choice, nothing will feed fuel fast enough using vacuum, when it runs out, the engine is at low vacuum with airflow across the boosters, the PVCRs and main jets are providing fuel, as the vacuum rises the PV closes and leans then it's mostly the mains, although a little from idle and transition (but not a lot as a percentage)

Although you have low idle vacuum with that cam, you likely have more when cruising, so when you stomp it, the accel pump gies it fuel, then there is a delay until the PV starts. This makes sense based on the fact that your 37 boosters helped by slowing the rate of fuel, but if you wnet smaller it backfired. Worst case, a 6.5 PV will be slightly too rich at part throttle cruise.

If you have 6.5 PVs, I'd give them a shot, make sure you have throttle plates set right and idle a/f set as clean as you can, and see how it goes

When you set float level, realize it's a tuning tool as well. Up or down slightly will increase or decrease head pressure on the PV and main circuit. Keep track of what you do, and I usually start at the float looking level when upside down and bowl off, and when you get close, count "flats of the nut" back or forward and keep track and see. If it seems like it needs a little fuel, raise it a little.

Last thing, be careful about tightening the float bowl screws too much, Holleys can "dog ear" or "elf shoe" in the corners and then cause cross channeling at the gasket. Tighten enough to not leak, but don't strong arm the float bowl screws
 

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Two other things, I would not make your timing come in quicker. All in by 2600-2700 is likely fast enough. You get it going too quickly and start pinging, you may break parts as you sneak up on a nice clean/lean-ish mixture

I would look closely at what I asked before on the compression, if you need help calculating based on part numbers and experience for a good guess, glad to help, but there is a method to my madness

The lower the compression, the more a late intake valve closing point will affect vacuum and part throttle/low RPM cylinder fill. Most heads are a bit larger than advertised, as are Ford factory heads, most pistons are deeper in the hole than we'd like, and ultimately you could counter than by advancing the cam, especially if the cam is slightly rowdy.

In fact, that brings to the next question, did you degree the cam, I have had two come in that tolerance stack put them 2 degrees late and it can make a difference
 

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Thanks for all the great info 427!

I installed the cam straight up and it came out to Comps specs. I don't have the card with me and its been quite a few months so I cant remember the numbers.

I'm using Edelbrock heads with some porting done to them. 72cc heads. I did not check the chamber size, they are new so I assumed it would be pretty close.

Eagle did the calculations for me before I bought the kit, 0.040 gasket, 72cc heads and it came out to 10.8:1. My block was zero decked to 10.15. I did some calculations for static and dynamic compression and it came out to 10.7:1 and 8.03:1. My cranking pressure is 193 psi +/- a psi.

I will try the 6.5's and see how it does. Floats are set as per Holleys instruction, just below the screw hole.
 

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Thanks for all the great info 427!

I installed the cam straight up and it came out to Comps specs. I don't have the card with me and its been quite a few months so I cant remember the numbers.

I'm using Edelbrock heads with some porting done to them. 72cc heads. I did not check the chamber size, they are new so I assumed it would be pretty close.

Eagle did the calculations for me before I bought the kit, 0.040 gasket, 72cc heads and it came out to 10.8:1. My block was zero decked to 10.15. I did some calculations for static and dynamic compression and it came out to 10.7:1 and 8.03:1. My cranking pressure is 193 psi +/- a psi.

I will try the 6.5's and see how it does. Floats are set as per Holleys instruction, just below the screw hole.
Good to reply to a post that has info and a guy who understands it. If you could post the type of piston you used it would help too. Eagle kits use Mahle at 7 cc or 20 cc, neither make sense for your numbers. Also, if you can confirm it's a .040 over 390 with a 4.25 stroke, not some other combo that got you to 447, like a shorter stroke 428

Here is why I ask. A Comp 308R is not 308 advertised, it's 312. To get to your 8:1 using PKelly's calculator, (all are good but I have hundreds of builds using that one and consistency makes them show trends) I have to get you to almost 11.86:1 to get your 8:1 DCR. In fact, 312 is calculated at .020, actual duration at the valve may be more because your lash divided by rocker ratio puts the valve coming off the seat (assuming .027 or so) at .015 tappet rise, so DCR could be slightly lower

Secondarily, Edelbrock heads, from the factory, if uncut, are usually closer to 74 cc, AND if you had port work done and the seats touch up, the valves can recess a little to add another cc or so, depending how much they cut.

As an example, if I use 7 cc, a 1020 Felpro gasket, 74 ccs for the heads, and a 4.09/4.25 447, I get 11.03:1, when I add the cam at 106 using 312, I get DCR at 7.51. That's fine the motor doesn't make power where that is calculated, but you likely have more torque and vacuum available if you advanced the cam. FYI, best way to use DCR on the street is a max of about 8.3 with alum heads, less on iron, not a minimum.

So, if you can show the parts you have, we can figure out compression (with a couple assumptions still), but what I showed above isn't good enough to evaluate yet, just showing how I am thinking, but my gut says you have less compression than you think

That being said, 92 degrees of overlap for a 308R, usually can idle around 900 RPM on a big inch (482-ish) FE if well tuned, so it makes sense that yours is very low vacuum and likes over 1000. Overlap and intake centerline, along with ring seal and cubic inches, drive your vacuum, all of yours are making sense.

If my calculations (which were a bit of a guess) were right, I'd drive that cam forward to 102 ICL, keeping in mind you have to check intake valve clearance again with the cam moved. It'd bring low end up a little and likely a couple of numbers of vacuum, and then I'd return the carb to stock as Holley built it, and recurve to 20 initial, 18 in the distributor, all in by 2600-2700. Then start tuning again, but it probably wouldn't want much

However, your plan to try the 6.5s now is a smart one, what you are doing is giving it a clean pump shot, but the PV fuel is a little late due to the 3.5s. The 6.5s might get you close enough to enjoy it as is.

Regardless, if you can post the rest of your parts, happy to discuss more. Additionally, which intake and do you have plenum cut and/or an open spacer?

Last, how much gear in the car, and how is the tranny set up, C4 or C6 etc? That's a lot of cam for a ported head 447. You likely could have an absolute screamer, but I am spinning 461s at 6000-6100 in the mid 500s for HP with 291/237 duration hyd rollers. Adding 25+ degrees of .050, if the heads are good, could be putting you way up there for a peak, again driving the earlier ICL if the pistons will allow it.

Flow numbers on the heads would be helpful too if you had it
 

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Discussion Starter #18
Thanks again!!

So I threw the 6.5s in this morning and guess what..... no bog. I can’t thank you enough 427! The car runs great, pulls hard till around 6700.

There is also the possibility I did the calculations wrong haha. I don’t think I will adjust the cam this year, maybe next spring. I want to try the new promaxx 200cc cnc heads with a trick flow single plane.

So now once I find the harness to my wideband I’ll get the jetting dialled in. So here is my complete set up, I appreciate you taking the time to help me!!

Engine
-360 block bored to 4.09, magna fluxed and sonic checked, decked to 10.15, arp studs
-oil mods done by myself
-Melling hp pump with 5/16 drive from precision oil pumps.
-5/16 to 1/4” oil pump shaft
-moroso 8qt pan w/ moroso pick up
-Eagle crank 4.25 stroke
-Eagle 6.635 forged I beams
-Mahle 4.09 forged 7cc pistons
-Comp 308R solid roller, matching Comp springs
-lunati solid rollers
-cometic MLS head gaskets, 0.040 compressed. 4.25 hole
- Performer RPM heads, bowls stock, stock valves and seats. Mild porting done by me and port matched. Don’t know flow numbers.
- Precision Oil pump full roller rocker set up.
-Smith brothers 5/16 .083 wall pushrods
-performer Rpm intake, mild porting and port matched by myself. Don’t know flow.
-Holley 1000hp with annular boosters.
-MSD Pro billet distributor
-MSD 6AL
-MSD HVC 2 coil
-MSD 8.5mm wires
- FPA tri-y headers 3” collector
-3” exhaust
- all assembly done by myself

Transmission/ rear end
-1968 C6 out of F250
-full rebuild done by myself, performance clutches, billet servo, etc, etc
-TCI reverse manual valve body
-custom drive shaft with 1350 joints
-9” 28 spline, Easton true trac, 4:11 us gears, put together myself.
-28” tall tires
 

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Discussion Starter #20
I spoke too soon..... Bog is back...

this morning I put the 6.5 PV’s in, checked float level, raised it up a bit and installed rear jet extensions since I had the bowl off.

I let the car warm up then left the house. Hammered the gas when I was at a stop sign and blew the tires off no problem. Tried it a couple times more and no issues. Dropped the car off at the tire shop. Took the car home with no issues.

Checked plugs and they looked extremely white, went up 2 jet sizes.

Took it out a few hours later. Was at a friends place bragging about how it runs. Try to do a burn out and it starts bogging bad. I think it was heat soaked and gas was boiling out the vents. It didn’t over heat.

So I dropped the floats down a bit and took it for a drive. It didn’t flood out now but still was bogging.

Dropped jets down 4 sizes. No change to the bogging. Runs a hair better wot at high rpm

Only thing I can think of is possibly heat soaking causing the issue now, gas heating up and forcing its way through. I do have a 1/4” spacer on but maybe I need to do some more. If it’s not raining tomorrow I’ll take it out to try the Heat theory
 
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