Time to ask for help. Timing and tuning problems.

I haven't posted in a long time and my plan was to modify the log head and post my amazing results after it was all done. But what on earth goes as planned, right?
Back story:
Unmodified short block, stock as far as I know.
Stock C4 tranny.
Later large log head from a 250 with proper machine work done, can't remember what year, I don't think it matters for my problems.
Motorcraft 2150 funneled through the stock log intake.
Electronic ignition and distributor from a 78 fairmont, IIRC
Timing was always a little weird, seemed to like being around 20~30 degrees advanced, which I think something is wrong there.
I have never had any pre ignition, detonation, knocking or pinging, no matter what i do with the advance.
Clifford 264 cam
Dual out clifford header with their heavy duty valve springs.
Stock rocker assembly and such.
Everything ran pretty good before, no real problems, I just felt like there was more power somewhere. Like I never really got the timing and fuel right.
One thing that may make a difference here, it would die or try to die if I laid in to the gas pedal a bit and let off.
Also, upon snapping open the throttle it would take a moment to rev up.
It sounds like a beast and free revs amazingly. Really sounds healthy when parked, not so much when running through a gear.

I pulled the head to do the direct mount 2bbl conversion/modified log conversion.
I reset the fuel air mix screws to 1 1/2 turns out to start out.

The thing fired up pretty easily once gas got up there.
Again, revs good sounds amazing.

I pull it out of the garage and begin my attempt to tune the thing. I start with getting the idle mix close enough to feel comfortable with a drive around the block.
Everything else was the same as before.
It is just terrible. Stumbles makes funny noises while i'm driving, it's slow, uneven acceleration, bla bla bla...very disappointing.
So i get out the timing light and vacuum gauge and begin screwing everything up.
The timing like i stated before was around 20-30* advanced according to the marks on the pulley. I am pretty sure these marks are accurate as I had it at TDC when i pulled the head and no. 1 was right at the top of the stroke. Though, 20* off might not be noticeable if i wasn't specifically looking for this problem. So i set it at 10* and begin working on the idle mix. It runs, revs, goes into gear without dying. I back it out of the driveway and it dies and won't start. I knew from past experience to give it it's desired 20-30* advance to get it to start back up and pull it back in the driveway. I made some extra marks on the pulley at 10* intervals to get a more accurate reading of what i'm doing. It doesn't seem to make much difference where i put the advance, so long as i adjust the idle speed and idle mix. Though, on some settings it dies going into gear and doesn't like to crank and start. It seems to be best around 20* advanced. I don't think that can be right. How sensitive is the initial advance? If i adjust in 5* intervals, could i just be skipping over the only setting that it will be happy at?

Everything is just all over the place with this. Always has been. Could something seemingly unrelated be messed up that is keeping me from solving this problem? Could there be a problem with the transmission that makes it seem like there is a problem with the motor? Could there be a problem with the distributor or ignition box that are not affected by the adjustments i'm making? Does it matter if the distributor is "a tooth (or 3) off" as long as i set the timing accordingly? I have read on this a lot and i can't seem to find clear answers.

If anyone has any advice, resources, or can recall a thread outlining a similar problem i will be eternally grateful.

-Steve

Back to basics, do you have really good hot spark, nice blue color with cackling sound ? Not orange/yellow.
Valves adjusted properly ? ( too tight leaves the valves off the seat...)/Compression test ?
Vacuum leaks ( anywhere from PVC valve to carb attachment ).
It's the easy ones that bite the hardest.
Keep us posted,
DannyG

Sam, you should have zero decked the block.
You should have milled the head enough to get it down to 50 cc's
Verify that TDC is correct. These six cylinder dampers have a problem of slipping on the hub.
Use the Victor head gasket it is .006" thinner than the felpro gasket.
What are your distributor specs????
With that camshaft you need a looser converter.
Once you get the ignition correct then you can fine tune the carburetor correct.Bill

These are old, old engine parts, getting older.

1.08 or 1.21 carb?

Pull the K cluster out of the 2150 Motorcraft carb. If its not got split tubes, i'd be very supprised.

viewtopic.php?f=1&t=70651

Post back if you can.

http://www.jeepforum.com/forum/f12/moto ... y-3259089/


Don't be supprised if the casting at the log intake is cracked.


See MPGmustangs issues when dealing with hishairline fractures in his direct mountlog head. Its not possiable to make a 2bbl idel if there are leaks like this, and they do occur.

viewtopic.php?f=51&t=68406

I will get back into this later tonight and check everything you guys recommend.

DannyG":3htn78zt said:

Back to basics, do you have really good hot spark, nice blue color with cackling sound ? Not orange/yellow.
Valves adjusted properly ? ( too tight leaves the valves off the seat...)/Compression test ?
Vacuum leaks ( anywhere from PVC valve to carb attachment ).
It's the easy ones that bite the hardest.
Keep us posted,
DannyG

Click to expand...

I could probably do the spark test and compression test this morning. I do think there is a small vacuum leak that i can address this evening.
I have hydraulic lifters and non adjustable rocker arms. Was it a huge mistake to leave the stock rocker assembly?

wsa111":3htn78zt said:

Sam, you should have zero decked the block.
You should have milled the head enough to get it down to 50 cc's
Verify that TDC is correct. These six cylinder dampers have a problem of slipping on the hub.
Use the Victor head gasket it is .006" thinner than the felpro gasket.
What are your distributor specs????
With that camshaft you need a looser converter.
Once you get the ignition correct then you can fine tune the carburetor correct.Bill

Click to expand...

Didn't deck the block.
The head was milled to 50 cc's
I will verify TDC tonight and post back.
I wanted the thicker head gasket because i have plans for forced induction later on and wanted to keep the c/r down if possible.
No clue what the distributor specs are. It has vacuum advance as well as centrifugal. Probably not what you're after.
I have no idea what a looser converter is. Could you direct me toward some information? My budget is a huge obstacle as i'm pretty much poor.
PS, i am interested in one of your recurved distributors if this problem doesn't eat up the last of my budget.

xctasy":3htn78zt said:

1.08 or 1.21 carb?

Pull the K cluster out of the 2150 Motorcraft carb. If its not got split tubes, i'd be very supprised.
/

Click to expand...

I believe it is the bigger version of the 2150 so probably the 1.21 venturi size
I have had the carb apart a dozen times and has always looked good. I'll pull the K cluster out tonight and check.

Thanks everyone, i'll post back tonight if the kids let me into the garage.

-Steve

Timing chain?
Slipped balancer?

Ok i performed a few tests.

TDC marks on the balancer pulley are exactly accurate

The spark is bright blue when observed while running with a spark tester and makes an audible popping sound

The compression test brought interesting results:

1: 135
2: 135
3: 135
4: 155
5: 160
6: 155

I read in the manual that anything over a 20 psi difference is cause for concern. Is it weird that the front 3 and rear 3 are so close to each other?

I probably won't get to address any of the other issues for a few days. Pretty busy during the week with kids and work.

I did not do a wet compression test, i suppose i'll do that next time i get a chance. things aren't looking very good. but the fact that tdc is accurate suggests there is likely another problem. bummer

we'll definitely something isn't quite right! A wet compression test will tell you if it's ring seal. Otherwise looks like some valves aren't sealing real good and or the head gasket is leaking a little bit too. Good luck

While i understand that the "failed" compression test is bad and warrants further investigation, I don't see how it could possibly be related to my bizarre timing problems.

What are the consequences of letting the poor compression test go for a while? I want to get everything else figured out before I take this motor apart again.

Does anyone have any further thoughts on why the car wants to be set at 20-30* advanced? If i messed something up when I installed the cam many years ago, would that produce symptoms like I'm experiencing? I drove it for several years between now and when i put the cam in.

I just can't afford to address the compression problems right now, even if it means the car sits a while Could there be any simple and easily fixable explanation for the compression results?

Though its not really ideal to have that much compression difference you should still be able to tune around it enough to run decent enough so you can drive it. Do you happen to have a good Tach or Tach / Dwell unit to use and or a vacuum gauge? How long has it been since the carb has been cleaned real good and a new rebuild kit installed? Not knowing how you dialed in or set up the cam timing could also make some problems and to figure that out you would need a degree wheel or timing tape on the damper, and a dial indictor. How were you able to verify that the timing Mark is accurate? If you had happened to use an offset crankshaft woodruff key when setting up the cam then this could explain the timing marks not being quite right. Though it's not unusual for an engine to like 12 to 15 degrees of base timing with a mild cam. With it set to the 20 to 30 dose it start normally / easy? IE not kicking back against the starter when cranking. Good luck

Keep talkin Steve. We all got kids'n work (i love em both) but we'll get U there!

I do not have a tachometer, but can easily justify getting one. I have used a multimeter for this before, but i really don't like doing it that way.
I do have a vacuum gauge.
I cleaned the carb last summer and it seems to stay pretty clean. Would be happy to rebuild it if you think it will help.
I probably effed up the cam install, i was like 20 years old and super anxious to drive it. I can't remember how i set up the cam timing and could have possibly messed that up.
To verify TDC, i pulled the no. 1 plug and watched the piston reach top dead center and moved the crank back until it started to drop then forward until it started to drop and split this difference. Then looked at the timing mark and it was exactly at TDC.
I probably got the woodruff key at Sears hardware and didn't even know an offset key existed.
At 20 to 30 degrees, it is the only way it starts easy, runs, doesn't die going into gear. It has never kicked back against the starter, never pinged, detonated, no preignition.

It sort of sounds like the cam is the source of the timing problems.
If the cam is off, would it cause my weird timing issues? This seems like an inexpensive fix after purchasing the tools i need. Fixing the compression, however, will be a battle for another day.
I will get the tach, carb rebuild kit, and whatever i need for dialing in the cam. I feel like there is a light at the end of the tunnel. Just hope it's not a freight train.

Thanks so much for the help.

Ok for now let's forget about the cam maybe being a problem, as you would need to take things apart to find out. It's a good idea when doing performance mods to keep a written engine build and tuning Log book that you can refer to. Then when your tuning it also helps speed up the process plus when you have a good base line tune with all its details it's lots easier to get back to what works. Since your carb is probably good enough condistion for now don't worry about a Kit yet, we need to do some of the tuning and a few tests to see what if anything needs some work.

Fist things first if you can get ahold of a tach and vacum gauge we can start doing the basic tune up. Over the years I found this is a good order to work from and a quick way to dial in a basic running tuneup and some of the specs to use to get you into the ball park! You can just skip ahead on the list for any of the things that you have all ready done.

1. Set your Spark Plug Gaps for DSII (.044 to .045) and then install the plugs. If you can post a picture of the plugs showing the electrodes in cylinder order it could helpful too. With # 1 on TDC of your dampers timing Mark remove the distributor cap and note the position of the rotor to the #1 plug wire tower and or post a picture showing it.

2. Next set your Base Timing with Vacuum line to Distribitor disconnected and 12 to 16 degrees BTDC. i.e. Also would be helpful to know the Air Temps and Elevation, etc. in your area. I personally like to use a Ported Vacuum Sorce if possible for any street type car IMOP this gives better drivability and economy. Manifold Vacuum will also work though it takes a little different level of tuning, so also let me know which way your using now.

3. Now you will need to verify the carbs float level setting is correct and for an Autolite or Mortorcraft carb you will need to remove the top fuel bowl cover to check and measure the float is a level height roughly this is measured 1/16 inch back from the front of float and measures 3/16 inch down from top of fuel bowl without the gasket, lightly pressing down on the tab at rear of float to seat the needle. That's usually close enough, but look at the position of the float right after you pull the top cover with how much fuel is in the bowl and also the type float you have brass or Nitrofil. Later on you can also check the wet fuel level it should be checked with the engine warmed up good and idling with the carb top off you measure down to the fuel level from top of fuel bowl.

4. At this point you should also have the Vacuum gauge hooked up to see what kind of Vacuum reading you have at idle RPM and with an Auto trans this is checked with the parking brake set or someone else in the car with their foot on the brakes, the trans in drive. Report the reading your getting and if it's a steady reading.

5. Next step is to set your carb mixture to the lean best idle, the starting setting after a carb rebuild is usually 1 1/2 turns out. With a tach hooked up and engine warmed up to normal operating temp. Turn the mixture screw or screws each in until idle speed drops slightly then turn the screw out until you reach highest idle RPM then turn the screw back in 1/4 turn (Leaning it) this is your lean best idle setting.

6. Last set the Curb Idle RPM (500 to 600 in Drive with parking brake set). This setting is for a mostly stock engine combo (and a mild cam), you may need to raise it some depending on your location etc. IE with car in gear punching it and taking off there shouldn't be any stumbling.

7. If the carb still has all the working choke parts then it now needs to be set also. Auto or Elec. choke is set about 2 index marks past center Index Mark to the Rich side. And with the fast idle screw set on the fast idle cam index Mark (>) you will want to adjust screw so it's from 1200 to 1500 RPM or just a high enough RPM so that the car when cold will drive without stalling. When warmed up choke should also release the fast idle cam and return to the normal curb idle and choke blade should be fully open. Recheck this setup after the engine is cold again to see if the choke resets itself on the Fast Idle cam and the choke blade closes.

For the best results I usually repeat steps 5, & 6 just to verify that the carb settings are right. You know the tune is good if the car starts when warmed up without touching the gas pedal! This should give you a good basic tune to adjust from and fine tune it since every engine can like a slightly different tune. You can then try molding the tune some (do only one thing at a time though) until you find the sweet spot that your engine likes. Remember if you change base timing then you will also need to reset the carbs Idle Mixture and reset the Curb Idle again. If you run into any problems were something doesn't work right in the tuning order then stop there and let me know what happens. Good luck in your tuning!

That was....AMAZING!

It will probably be this weekend before i get this finished. I am so glad I asked for help. I don't have any friends or family that are into cars past the paint color.

Thank you!

-Steve

Ok good luck!

Ok, making progress now. I addressed the vacuum leak to start. I replaced the spark plugs, just because I wanted a fresh start. The ones i pulled out were pretty consistently black covered in a light layer of carbon(?).
I set the time to 14* and adjusted idle so it would run, around 900.
I checked the float level, it was about 1/16 from the top at the point away from the needle, i believe my carb is mounted sideways compared to its stock application's orientation.
I adjusted it to 3/16, as recommended. I didn't check again wet while running, ran short on time.
It is a nitrofil float, i bumped the float as i was pulling the top off, so i didn't get to accurately check the fuel level.
I checked vacuum through the spark control port, not sure if that was the one you wanted me to use, but it was at 0 at idle.
I checked vacuum at the manifold, around 7 inches and fluctuates about 1 inch.
I set the idle mix as described, then set the curb idle around 700, it wanted to try to die anywhere below 650.
This put the idle in park around 1100 rpms.....
I didn't get to work on the choke. It is automatic and the butterfly opens steadily to wide open as it reaches operating temp. I know the fast idle is not set right. I took off the vacuum part of the choke and capped the line because of clearance issues with plans to switch to manual choke. And i may still do this, I just don't know enough about the choke circuit in the carb to know if i can leave it the way i have it. From what i gather, the part i removed was just to make sure the choke butterfly isn't completely closed with the motor running. Please advise if this is a mistake or if it may be causing problems.
I did repeat steps 5&6 and the only thing i changed was the Idle screws went in one quarter turn.

When i put the transmission in gear to set the curb idle, it ran fine for about one minute then the RPMs dropped to about 5-600 and it nearly died. That was weird.
Also, the exhaust side of the engine bay was too hot to keep my hands in there adjusting the carb for more than 20 sec. or so.
...Also, after i shut the motor down, i could see fuel dribbling into the intake, i think the fuel may have been boiling?

I took it for a drive around the block and it is still slower than before the conversion, much slower. But it did not die or try to die. I think i can tune from here, but i am almost certain i will be advancing the timing back to 20 degrees or so. :arg:
It now starts fine, goes into gear without any adverse side affects, and actually drives, so that is progress :thanks:

7" of manifold vacuum seems very low ? If you put your hand over the top of the carb ( as if to choke off the air supply) will it still run ?
It just feels like a vacuum leak someplace ?
You could use a spray of starting fluid around the carb base while running ( apply all safety precaution for flammable fluids and hot exhaust manifolds), spray a puff near the base of the carb and see if your idle increases ?
Does the distributor rotor point to the # 1 plug wire at TDC ( on the firing stroke) it can't hurt to doublecheck that the plug wires are in the correct firing order too ?
Keep us posted,
DannyG

Steve, that's some good results so far

1. On any of the places these Ford sixes can have a vaccum leak make sure you check and fix them all. Best and safest way is with Smoke, other ways are dish soap water mix, carb cleaner, propane, etc. X2 if you use anything that is highly flammable be very careful it's also a good idea to have a fire extinisher handy too. The Main Places to check for Vacuum leaks are the Carb base gaskets, PCV and its hoses if they are not tight install small hose clamps also check its operation when running. Pull it out and put your finger over the open end severial times and release the valve should cycle quickly. And last of all the small vacuum lines / hoses be sure they are fitting on their connections snugly if not they need to be replaced or at the least make or find some way to clamp them tighter.

2. The vacuum reading fluctuation of 1 HG is likely caused by the compression imbalance between cylinders, you Mentioned that you have stock rockers do you happen to remember if they are the adjustable type or fixed? You can also pull the valve cover off if you want to check them.

3. Yes that vacuum reading is perrty low this could be from a few different reasons like the compression, camshafts setup position (timing), or late ignistion timing. By chance do you happen to remember what timing chain set you used when you installed the camshaft? Where on the engine did you hookup the vacuum gauge?

4. For an accurate engine vacuum reading the gauge should be hooked up right to the intake manifold log! Look for a threaded bung, a T, or pipe plug just below the carburetor's base its about 1 1/2 inches down on the side of the Manifold Log and install it there if it's not hooked up there all ready.

5. So now Let's try adding some more base timing and see if the vacuum comes up any. Did you by chance happen to take a begining vacuum reading before you starting changing the timing?

6. We need to either get a higher engine vacuum signal or the carb's power valve will need to be changed to a lower rating.

7. By the condistion of plugs your car is running very rich the high float setting was a big part of that. The Nitrofil floats can also sometimes absorb fuel when old and become too heavy and sinking allowing too high a fuel level. Your floats sounds as though it's still in good condistion and we can try lowering the float another 1/16 inch too. Ie 1/4 inch from top of fuel bowl.

8. Excellent yes that's the right carb vacuum hookup (it's a ported vacuum) that's used for the distributors vacuum advance can, and 0 vacuum at idle is just what we want to see.

9. Yes the choke needs to be set correctly or can cause the engine to be too rich. All Of the parts are needed to operate correctly. Is a hot air tube / line (stove) hooked up to the the choke body? You can get universal replacement kit at about any auto parts store or make your own out of a lenght of brake line and a compression fitting nut and faruel to conect it to the choke body. Next run it down to the exhaust manifold or headers and wrap it around a tube don't forget to slide on the insulating sleeve on before for the upper part above the manifold too. When the engine is warmed up the choke blade should be held wide open with a slight amount of spring pressure to holding it tight. Last set the fast idle RPM as in the above post.

10. I missed this very important detail in your above answer but just caught it by rereading the post tonight. You said fuel was dribbling into the intake after shutting down the engine this is a sign that the wet fuel level is much to high. You may have a bad float you could replace it or else check what the wet fuel level is again with it running. Again there should not be any fuel going down the throat of the carb after the engine is shut off this not good for the rings to have excess fuel washing down the cylinders.

Steve, kee going and good luck Edited

I'm wondering if the distributor advance isn't working.
If you have to add that much timing (20°)to get 'er going then that's where I'd look.
Maybe be a busted spring in there?