Engine Doesn't Idle Smooth
- Thread starter StarDiero75
- Start date
Bill ? "...but yours are already done. ..."wsa111":olgr4tgs said:
his were toasted on break in w/long period of cherry red - near white hot - manifold.
I think that means he will have to 'machine' what he has or put in 'new' seats, no?
Alright guys, so great news. He vacuum tested the chambers and the intake. The chambers are solid, no leaking. Apparently, my EGR block off has been partially sealing, hence why the car acts weird. The hole where it goes in and the carb adapter surface are seperated by about .052" of material at the top of the hole. The paper gasket stuff wasn't sealing it. He's gonna try some tricks but as of now here's what I'm thinking:
•Either fit a tapered puck into it and tig it with nickel rod
•Tapered puck with JB weld or Belzone
•Reuse aluminum block off plate like what I had except use Motoseal by Permatex
•Rubber expansion plug
•Freeze plug
I'm kinda leaning towards the freeze plug or puck. Any ideas guys? Also, since the head is at the shop I cannot measure the big EGR hole in the side of the intake. Its the one from 1980. Does anyone know the size off hand, or can measure it?
Side note, head is not warped b/c the head gasket looked brand new when I took it off. Nothing blown out or wrong. But I will have it shaved slightly. To ensure flatness.
•Either fit a tapered puck into it and tig it with nickel rod
•Tapered puck with JB weld or Belzone
•Reuse aluminum block off plate like what I had except use Motoseal by Permatex
•Rubber expansion plug
•Freeze plug
I'm kinda leaning towards the freeze plug or puck. Any ideas guys? Also, since the head is at the shop I cannot measure the big EGR hole in the side of the intake. Its the one from 1980. Does anyone know the size off hand, or can measure it?
Side note, head is not warped b/c the head gasket looked brand new when I took it off. Nothing blown out or wrong. But I will have it shaved slightly. To ensure flatness.
That's great news, you could drill the holes to correct size to tap and install a pipe plug or Allen head set screw. Use some Permatex non Harding to seal it. Good luck 
There is not enough material to tap, same for welding...rubber expansion plug might work but would be hoakey, bad if parts came loose... Not wild about tapered plug...Expansion plug may come loose ad get sucked in, I do not like the idea of adding stress to a thin weaken area...I would go with the easiest and least intrusive means ,like the plate and motoseal...If that does not work then you get fancier..Like a plate with a plug to fit in the hole then there would be more surface area for the moto seal to work with..Maybe plate with plug with a grove and o ring
Expansion / soft plug will drive it tight enough to stay use some of the liquid aviation sealer around the hole to seal it. Good luck
Alright boys, as of now it is sealed. Apparently 2 of my bolts were 2 long and intersecting. He shortened the bolts and used some sort of aircraft grade sealant. He vacuum tested it and supposedly it is solid. So I'm not touching anything lol. Everything tested to 25 inches as opposed to the 17 when I brought it in. Very happy I took the head off. I'm hoping to have the head done by Sunday night. I'll let you all know how it runs then.
I actually already have one in the car, one step ahead lol
So I got the car running and I'm having similar issues as before but the car idles a hell of a lot better and it shuts off instantly, no sputter shut off. My vacuum fluxuates still. So here's what I'm doing:
Started off adjusting hydraulic lifters as per classic inlines. Finished and the car was fluttering vaccum around 15-16.
Started slowly backing all the valves off till they made noise, got better but still did Adjusted per Classic Inlines page but without preload turn. Vacuum came up to about 17ish but still fluttering
Finally backed all the intake valves off an eighth turn and its pulling about 20 and pretty steady. I'll have to fine tune since they are a hair loud.
What kind of vacuum at idle should this kind of setup be running? I know hydraulic lifters should have some sort of a preload on them but for some reason it seems like I just can't get any without making the car run weird. Are the Schneider lifters just that stiff? Or could it be that I'm not running the springs they recommend? I am running Ford 302 exhaust springs, the ones mentioned in the handbook. I remember the schneider springs being about 100lbs while these are 80ish. Could any of that cause my problem here? The lifters could just be too stiff and require stiffer springs?
Started off adjusting hydraulic lifters as per classic inlines. Finished and the car was fluttering vaccum around 15-16.
Started slowly backing all the valves off till they made noise, got better but still did Adjusted per Classic Inlines page but without preload turn. Vacuum came up to about 17ish but still fluttering
Finally backed all the intake valves off an eighth turn and its pulling about 20 and pretty steady. I'll have to fine tune since they are a hair loud.
What kind of vacuum at idle should this kind of setup be running? I know hydraulic lifters should have some sort of a preload on them but for some reason it seems like I just can't get any without making the car run weird. Are the Schneider lifters just that stiff? Or could it be that I'm not running the springs they recommend? I am running Ford 302 exhaust springs, the ones mentioned in the handbook. I remember the schneider springs being about 100lbs while these are 80ish. Could any of that cause my problem here? The lifters could just be too stiff and require stiffer springs?
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Here is how I set Hydrolic lifter valve lash for many decades. Back them off until they clatter then slowly tight it down again until it stops then tighten an additional 1/4 turn. You may get some clatter in the morning on first start up if the lifters bleed down until oil pumps them up again. This dosent hurt anything but if you don't like the noise you can go up to 1 full turn.
On the 302 valve springs they can be a little help when running the stock cam however they aren't enough seat pressure for most any of the aftermarket cams. This will cause early valve float at higher RPM's that these cams are designed for you should go with what is recomemed by the cam company. You will want to see as much vacuum as you can get but it's going to very with tuning as your seeing.
The bitters are not to stiff but they need to be adjusted correctly many people have trouble adjusting them and tend to get them to tight on the small sixes. Yes having the wrong seat pressure to low can cause problems in several areas. Good luck
On the 302 valve springs they can be a little help when running the stock cam however they aren't enough seat pressure for most any of the aftermarket cams. This will cause early valve float at higher RPM's that these cams are designed for you should go with what is recomemed by the cam company. You will want to see as much vacuum as you can get but it's going to very with tuning as your seeing.
The bitters are not to stiff but they need to be adjusted correctly many people have trouble adjusting them and tend to get them to tight on the small sixes. Yes having the wrong seat pressure to low can cause problems in several areas. Good luck
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Alright so its all back together. I adjusted the valves a little different this time hoping to get somewhere and nothing has changed, leading me to believe this is not a head issue what so ever. At this point I have:
Had the head vacuum checked and repaired= Valve seats and valves fixed, Carb adapter and EGR block off fixed. Now the head holds 25inHg. Great.
New Schneider springs to match the cam (it feels more powerful on the top end now).
4.0 V6 retainers. Much shorter, make the spring sit higher but at the proper height, and overall sit higher on the valve. No more valve seal woes.
I adjusted the valves by lifting up and down on the pushrod till it no longer wiggled up and down, then turned quarter turn. As compared to how I did it before they are much looser (ie pushrod still turns).
The car still has fluctuation in vacuum and wants to run rich at idle, 12-12.5. I'm still running 54 jets in the carb. The idle mixture screws are turned out like 3+ turns. The car wont even run at 1.5 turns out. At cruise around 30-40 she wants to run 16. At 60 in 5th she runs 14.7ish. At WOT she wants to run 13.3 sometimes a little leaner. When compression braking, it goes lean like 18+. Its a slow creep though. It starts to backfire bad when it does this. When compression braking and then putting the clutch in, it will sputter a little (goes lean). When the motor is still kinda cold it just dies.
The vacuum is weird. It'll hold steady for a bit, then it'll drop. Then come back up. Then i can rev it for a min, it'll stay higher for a min then slowly ease back into the 16 inHg it pulls.
Plugs are gapped at .050". They were .040 and I have run them at .045" with no change.
At this point, my money is 100% on the carb. The head is mint as far as I can tell. Being checked and good parts all in it. The DUI is from Bill, he does good stuff and I don't feel like this is it. The carb i bought from a dude with it on a shelf sitting outside. The only possible other thing maybe is the PCV causing too big of a vacuum leak. Its a NOS one from 1970. I put my thumb over it earlier and the idle dropped a lot, like maybe 150, 200rpm. Possibly it? I'll try running without the PCV and try that but if not, its gotta be the carb.
Any ideas?
Thanks guys
Ryan
Had the head vacuum checked and repaired= Valve seats and valves fixed, Carb adapter and EGR block off fixed. Now the head holds 25inHg. Great.
New Schneider springs to match the cam (it feels more powerful on the top end now).
4.0 V6 retainers. Much shorter, make the spring sit higher but at the proper height, and overall sit higher on the valve. No more valve seal woes.
I adjusted the valves by lifting up and down on the pushrod till it no longer wiggled up and down, then turned quarter turn. As compared to how I did it before they are much looser (ie pushrod still turns).
The car still has fluctuation in vacuum and wants to run rich at idle, 12-12.5. I'm still running 54 jets in the carb. The idle mixture screws are turned out like 3+ turns. The car wont even run at 1.5 turns out. At cruise around 30-40 she wants to run 16. At 60 in 5th she runs 14.7ish. At WOT she wants to run 13.3 sometimes a little leaner. When compression braking, it goes lean like 18+. Its a slow creep though. It starts to backfire bad when it does this. When compression braking and then putting the clutch in, it will sputter a little (goes lean). When the motor is still kinda cold it just dies.
The vacuum is weird. It'll hold steady for a bit, then it'll drop. Then come back up. Then i can rev it for a min, it'll stay higher for a min then slowly ease back into the 16 inHg it pulls.
Plugs are gapped at .050". They were .040 and I have run them at .045" with no change.
At this point, my money is 100% on the carb. The head is mint as far as I can tell. Being checked and good parts all in it. The DUI is from Bill, he does good stuff and I don't feel like this is it. The carb i bought from a dude with it on a shelf sitting outside. The only possible other thing maybe is the PCV causing too big of a vacuum leak. Its a NOS one from 1970. I put my thumb over it earlier and the idle dropped a lot, like maybe 150, 200rpm. Possibly it? I'll try running without the PCV and try that but if not, its gotta be the carb.
Any ideas?
Thanks guys
Ryan
Well guys.... i believe I solved it today. I took the PCV off and it didn't really fix the issue. What did fix the issue was taking the carb off, throwing it through a wall.... just kidding. The weird fluctuating vacuum, the non consistent running, and the running super lean all came from.......... drum roll....
THE POWER VALVE GASKET NOT SEALING. I hate my life right now. It wasn't tightned all the way and it wasn't sealing. Thr gasket was super wet when I took it out. But yet the cover didn't have a drop of gas on it. I guess it was sealing enough to work, but not enough to cause all these problems. I can't believe it turned out to be so simple. Thank you to those that suggested I look at the fuel system. At this point, thats all that was left. Hopefully the car keeps running like a skinned cat! Thanks everyone!
THE POWER VALVE GASKET NOT SEALING. I hate my life right now. It wasn't tightned all the way and it wasn't sealing. Thr gasket was super wet when I took it out. But yet the cover didn't have a drop of gas on it. I guess it was sealing enough to work, but not enough to cause all these problems. I can't believe it turned out to be so simple. Thank you to those that suggested I look at the fuel system. At this point, thats all that was left. Hopefully the car keeps running like a skinned cat! Thanks everyone!
StarDiero75, yes carb problems can somtimes be frustrating, I am so glad to hear that you figured out your erratic idle now. After all the other work you did and areas that you found that needed repairs these will also be an improvement itoo so will run even better. Carb's have to have carful assembly and precision settings to operate at their peak performance. Congratulations on sticking with it now maybe a little more fine tuning to find the sweet spot. Best of luck
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