rough engine

[tim21391]

you guys are like my 2nd home..you have helped me in so many ways all of you!! this isnt about a chevy though so im sorry admins if this makes u mad... i just love how u can always help me out so quick and easy my dad just bought a 67 mustang coupe.. body is excellent no rust what so ever for $2500 it has one dent in the door i think from hail or something... and its a 6 cylinder car but it was converted to a 302 v8 small block... and it runs really rough...we pulled the plug and they had oil all over them.. we went and bought new ones gapped them to .035 is that right gap?? my 72 chevy i gap to .040 and it runs fine.. anyways it runs a little better but when you are in gear at a stop it still is rough and u have to feed gas to it when your stopped or it will die... what would u guys check out first to solve the problem?? i want to suprise my dad since he is a trucker and is gone 4 days out of the week i want to fix it before he gets back... we changed plugs and shot carb cleaner down the carb and such and put sea foam down the tank.. should i tinker with the mixture screws or what?? it puffs white smoke out of the left tailpipe at times too.. and i need to put a new water pump pully on it to.. its tweaked just a bit... any help guys would be really great.. they wont let me drive it til its fixed and i tell you what being a teenager in a muscle car im anxious to drive it

[Gray Ghost]

Before you replace anything do a compression check on each cylinder....might save you time and money if one cylinder is dying or dead. Look for 125 PSI on all 8 as a good average. Anything under 100 is not good.

[1320tech]

I would start with a complete evaluation compression, cylinder leak down ,oil preasure,so you know what you have before throwing parts at it. this approach usualy saves money in the long run.

[d10s69c10]

yeah if all cylinders are within 10 psi of each otherr you have "decent rings"

sounds like your having a oil problem with smoke coming out of the pipe and mushed up plugs.

if that is not the case a rough idle can come from many things

Fuel/Air: check filters/pump/gas itself.
Spark: check all wires distributer cap/position.
Compression:well general if it starts cold your compression on at least half the cylinders aint bad.

after that you should have it running then maybe some tweaking with carb and ignition timing.

[Longhorn Man]

this isnt about a chevy though so im sorry admins if this makes u mad...

Not so much makin us mad, but it gets old having to move this stuff all over the board.
it's frustrating when the ones we move are from ppl who KNOW BETTER.

MOVED TO PROPER FORUM which gets plenty of traffic.

[tim21391]

ok longhorn im sorry i wont post anymore about fords..ill stick with my chevy.. i just seen some guys do it so i thought it was ok....

[Sillyoldman]

No problem here. I think most everyone here is a fan of American made muscle. Preference obviously chevy, but not limited to.

[retodd7711]

Originally Posted by tim21391

ok longhorn im sorry i wont post anymore about fords..ill stick with my chevy.. i just seen some guys do it so i thought it was ok....

We've got lots of F@rd owners on here, and your question is not a brand specific inquiry, I think he was referring to the proper forum issue.
Back to your problem. Start simple.

A "shot" of carb cleaner probably isn't sufficient for an old carb.
You really should disassemble,inspect,clean, and possibly replace any questionable parts on the carb. You'd be amazed how many problems a little piece of dirt or grease can cause.

If your plugs were old and worn out, chances the wires and dist cap are in the same condition. That's another area where a small problem can cause issues.

Don't forget to check the timing, could be another issue.
And post up a pic, if you're proud of it show it off!

[LONGHAIR]

ok longhorn im sorry i wont post anymore about fords..ill stick with my chevy.. i just seen some guys do it so i thought it was ok....

It not necessarily about the Ford...Just put your questions in the right place.
Longhornman indicated that he moved it here (General Discussion). This is the place for odd things, the ones that don't belong in any specific spot.

Also, "just because others do it........"

[cdowns]

plug gap depends on points or hei if you've got points you should be at .035 and you should be setting you're dwell at about 27degress or gap points at017// hei-electronic ign plug gap can go up to as much as .042-.045

like any other engine check for vaccume leaks bad cracked or missing or disconnected vaccume hoses//check for properly operating pcv system/loose carb mount/bad brake booster/ correct timing and timing advance working properly/ dirty fuel filter//dirty clogged air filter

[Longhorn Man]

this had been posted in the 67 - 72 chevy board...
it's a mustang, not a 72 cheyenne.
I personally like old fords and actually encourage discussion of ANY old cool cars on here.
But not on the truck forums.
Feel free to post ANYTHING in the general discussion forum, as long as it isn't political, religion, porn, or illegal ... it's good to go here in general discussion.

[tim21391]

to that one guy...i dont have a leak in the brake booster its manual brakes... and sorry longhorn i didnt know there was a general discussion board thanks ill post it there....i took my hands and covered the carb up and it died..so theres no vacuum leak auto zone said... then i took the plugs out and did a compression check...i think my problem is my piston rings are shot..cylinder one was at 100 psi.. 3 was at like 90.. 5 was 0 psi 7 was at 0 psi.. 2 was at like 62..4 was at 89 6 was at 90 something and 8 was at 95...so i think im gonna replace piston rings when football camp is over so that should be wednesday when i start tear down..take about a day or two to change those and ill get back to ya...then dad wants to rebuild the carb since it has been sittin for 2 years... plug wires looked decent they looked newer but ill change those here shortly too..dad pulled dist. cap and he said the points still looked good...so if i still have a problem after the ring swap ill change plug wires..points rotor and cap..and if it is piston rings.. would that explain why say if i turn a corner and i basically have to floor it to go...and when i do it just putts right up there it has no balls like no get up and go

[tim21391]

and i tihnk my choke is stuck shut so thats another thing...but piston rings is my main concern..

[tim21391]

picked this car up for $2500.... the black top was redone 15 years ago can u believe that...it has been repainted before too.. looked under it and seen hardly any rust its clean...floor pans look excellent..has one dent on the driver door about the szie of three fingers but thats it and its missin a few letters in the word "mustang"

[tim21391]

and i had to throw in a pic of it sittin next to my 72..i knew u chevy guys would like that

[Longhorn Man]

looks pretty nice in the pics!
The compression test looks pretty low across the board there, but the 5 & 7 obviously has something goin on.
In all reality, you are looking at a rebuild/replace to get the numbers back up properly. you could pull the heads off and see if it has a blown head gasket, but it'll still be a weak, worn out engine if you are able to seal it up.
Honestly, myself, I'd get a later model 5 liter with a roller cam in it, even a lame one from a town car or something, and slap it in there, you can put your carb on top to keep it closer to its roots, but a roller is light years ahead of whats in there, and won't self destruct with todays crappy oils.

[Gray Ghost]

Nice deal for $2500! Sorry about teh compression....doesn't look good. I think a complete rebuild is in order, there's bound to be other worn parts involved.

[tim21391]

so you dont think i should do the piston ring swap to see if that could help?

[Longhorn Man]

that'd be like taking a shower and puttin on last weeks boxers.

[cdowns]

you could check the valve adjustment to make sure the valves arent open when they're supposed to be closed /that could cause zero compression

[LONGHAIR]

Since it is 5 and 7 (next to each other) I would bet that Andy is right...Head gasket is blown between them.

[Gray Ghost]

Originally Posted by Longhorn Man

that'd be like taking a shower and puttin on last weeks boxers.

I don't believe I could have answered that any better....good one!!

Everyone I know that has done that has wound up doing it twice. I replace just about everything so that all parts stand on equal ground. You could re-ring it and it might last awhile, but my experience is that the next weakest link shows up right away....usually the cam or valvetrain.

[tim21391]

oh ic..i think the car will be settin for awhile..no money for a new engine

[tim21391]

ok well i was bored today so i pulled the valve cover off on the stang today...i took the 6 bolts off the cover and pulled the cover..and i heard something drop something metal im like aw crap i dropped the bolts...i look under the cover and see two rocker arms fell out...and a push rod was out of its hole..and i pull the cover off and the rocker arms arent straight.. and they are loose as hell like u can move it almost all the way around if u could its that loose...and this is the side of the engine where i had no compression in two cylinders so i think i found my problem....my old substitute teacher is coming by tomorrow to tighten up the valves.. and fix the rocker arms and push rods... ill give ya an update after its back together...cross your fingers its all good

[d10s69c10]

well that flat out sucks.. i hope your valves are ok i could be wrong here but if your rockers werent engaging the springs held them tight so you should have had compressionon the push strokes and a heck of alot of vacume on the pull. strokes.