Alright ladies and gents, I've a problem to pose. Since I'm at work and can't actually work on my car to test my own theories, I figured I'd gather some additional insight to mull over in the interim. Here's the issue: my little 289 is running rough when I give it gas. No tach installed, but I'm guessing somewhere in the neighborhood of 1800-2000 RPM and up. The details on the engine are as follows: .060 overbore, forged pistons, rotating ***embly (including flywheel and balancer) balanced. The short block work was performed last May. I installed an old set of heads (no work done) and was running it for roughly a year. Recently, I changed the heads, C5AE, fresh valves, seats, guides, etc. .005 off the face to true them up. Midrise aluminum intake, Holley 600 vacuum secondaries. Recent change to HEI ignition module. Roughly 10:1 static compression. Now, it ran fine with the old heads, just burned oil. When I installed the new ignition, no issues. I put on the new heads, no issues. It seemed to like a little much on the timing, 14-15 BTDC initial. (I'm thinking this is where my issue lies, truth be told.) But I tuned it up and adjusted the carb and didn't have any problems for a week. Now, I changed the trans (T5, but it doesn't matter, because it runs rough in neutral, or when the clutch is in, so I've isolated it to the engine), and it began this rough running. It doesn't really seem like a miss, possibly detonation, but it's not pinging at idle. Seems to run just fine at lower RPMs. I don't have the details on the cam in front of me, or I'd list that, but it's a high .400's lift, (I think .465 or somewhere in that range) and I think the LSA is 108 if memory serves. I'm not even going to guess at the duration without having it in front of me. Apologies on the length, I've found more detailed information is helpful in solving problems like this. I appreciate any opinions. Mike
just had an OT little piece of **** Ford do the same thing, similar symptoms, a week later it shattered a valve seat and is now on it's way to the s**** yard. Apparently all 2.0 L SOHC Fords will eventually drop a valve seat and eat themselves - who knew? I would start with a compression test, verify the ignition is functioning properly and from there move to the carb, maybe try another one on it. What's the timing all in and at what RPM does it come in? Good luck
I'm fairly certain the ignition is working properly, shy of crossfiring, which I haven't verified it is not doing. New wires, and such, which I checked the resistance on and they seem to be fine. I will have to verify the compression, I suppose it is possible that a valve/seat dropped. (Never trust anything, right?) I'll have to check on total timing, I don't know where it's coming in at for sure.
~14* isn't that far off . . . not enough to break up anyways. I think most guys would be in the 10-12 range on that motor . . . ? If you hold it at 2000rpm does it break up the entire time or is it just hitting the throttle?
Breaks up the entire time. It's not just hitting the throttle, so I don't believe it's a mixture issue.
Good call! that may be it - I adjusted them too tight on my mom's slant 6 many moons ago and yes it ran rough as hell!
New distributor? if not, possibly shaft wobble.... vacuum leak from carb gasket or power valve? cracked spark plug.. carbon track on cap.... intake gasket leak, check with carb cleaner
If its too tight I've seen rocker arms pop out of the exhaust but thats typically an all the time thing . . . I converted a pedestal deal over to roller rockers and tighten them down too much and it ran rough even at idle. But all the changed is your manual swap right? You didn't touch the motor at all?
When you switched to the T-5 did you change flywheels?I f you did,did you get the flywheel that has the same balance?If the above is OK then I go with either valve lash too tight and/or a vacuum leak at the intake manifold gasket.The initial timing at 14 degrees is OK,what is the total advance?Most 289s want no more than 34-36 degrees total timing! ROY.
It's a little hard to follow the bouncing ball . Let me know if this is correct ? Rebuild bottom end - Fresh bottom and old heads- ran fine Ignition change to fresh bottom old heads set up - ran fine. Roughly a year p***es. New heads installed ran fine for a week T5 swap in there some place - but where ? Flywheel and balance issues with fords so make sure that's correct. Also how old is the gas? Obviously, when a new problem arises got back to the last thing you did. And that would be the new heads themselves or the installation method of them. The springs should match the cam, do they ? Valve adjustment, wear issues, oiling issues, chamber size and compression changes, head gasket compressed height and squish or quench change. A weeks time is more than enough to do serious mechanical damage. So I'd by eliminating the possibility of scary expensive mechanical problems first and start with a compression test. Verify your valve adjustment geometry and bind issues. Find the cam card and the valve spring specs and make sure they are compatible. Check for vacuums leaks and any cylinders burning un accounted for air. Next move to fuel delivery problems because its easier to eliminate. Fuel pressure test while driving !!! Important !!! Very important.
Could be rockers, which are on the list of things to check. If anything I think they're a little loose, at least one of them is ticking. Hydraulic rockers. New distributor and cap and all, clean as a whistle. Could be a vacuum leak... Didn't touch the engine, correct. The trans swap was performed quite a while ago, all I did over the weekend was replace it (one was worn out, so I was putting in another one). I'm leaning toward there being too much total timing. Apologies on the bouncing. Correct flywheel and it was balanced with the rotating ***embly. New gas (89 octane, so I'm thinking that may be a problem too, though it's ran fine on 89 within the last week). Springs match the cam, no binding issues whatsoever. Oil is fine, possibly on the high side. When the rocker covers are pulled oil can be observed doing what it should. Definitely planning a compression test to verify sealing. Thanks all. Mike
Whose distributor? I've seen two MSD billet distributors have issues with the weights hitting the underside of the rotor oddly enough. Injected molded parts that someone forgot to deburr . . .
Really. I'll have to look at that and see. The thing that's getting me is that a simple trans removal and installation is all that I did here! And I've identified that as not being the problem. Fishy, no? After the head and intake install nothing was amiss... I'm still going through all that to make sure nothing changed, but still... Thinking maybe it's a motor mount. I've seen that before, and it could be a responsible party.
Maybe you bumped, Jared, cut, , shorted, kinked, detached something on your trans work. I can't see a motor mount causing any type of rpm related breaking up drivability issues or causing it to run rough in the drive way. Can you ?
Haha, point taken, but to tell you the truth, I can't see where anything else would have changed either!
Update: Removed the spark plugs and did a compression test on all 8; all of them are running right about 170, so no problems there. Found one cracked spark plug and one wire that I think was not quite seated on the plug, so I cleaned and gapped all the plugs and put them back in, replacing the cracked one. Adjusted the rockers. Put it all back together and it seems to run better, but still not great. I messed with it a little more, and I really need to get a tach, because I'm running on a tuned ear for RPM guestimates here, but it seems like it gets to vibrating around 15 or 1600 and on up through about 2500 or so. If I get on it is seems to clear up a bit around 32-3500. Runs great at idle. Just sits and purrs. Thoughts?
Runs great at idle. Just sits and purrs. Thoughts? Well this is an improvement and one of your issues solved. I dont know which is which or when or why off the top of my head but Fords have strange balance components and there is no mixing and matching. When I need this info I need to look it up. There was also a thread recently about a vibrating ford that turned out to be the wrong fly wheel. The part was new, correct description, correct part #, but pictures confirmed that it was indeed wrong and was not for that application. What do you know about your recently installed t5? And how do you think a plug got broken and wire pinched?
I'm with 31 Vicky withahemi. I've had a simular problem occur on a 289 with a automatic I owned. Should have been the right flex plate, was marked as such, but wasn't the right balance. Motor shook like it wanted out of the engine compartment. Sometimes it seems Ford made it so it didn't even like to work with themselves...
It could have a lean spot in that particular rpm range. If u went to better heads it may want more fuel. Pull the choke in that area to richen it up and see if the rough spot goes away. Or get it on a dyno and check a/f ratios
All the rotating stuff is 289 specific/correct. 28 oz imbalance on it. The later 302 motors are the ones with a 50 oz imbalance, and it will definitely cause a hefty vibration. The entire rotating ***embly was balanced when the shortblock was rebuilt, crank, rods, pistons, pins, harmonic balancer, flywheel, and clutch pressure plate. None of that has changed (so unless it threw a weight somewhere it should be good). As for the recent T5, I don't know much about it other than what the tag reads and what I observed. Tag calls it out as an 87 mustang 302 transmission, which would jive correctly with all my 289 parts and ****tershield and whatnot - yeah, I've been through this before. When I got the trans (saturday) I took it apart to check the internals and all, which seemed to be in fair working order, no terribly worn gears, bearings, or synchros. It seems to work well, though it has a noticeable gear whine, not entirely sure why as I'm more concerned with the engine at the time. The plug I'm ***uming broke when I installed it, as the sockets tend to hang up on the headers and make removal and installation slightly difficult, so I'm guessing taking the socket off I tweaked it and broke it. It was intact, just cracked. The plug wire I am ***uming just didn't seat properly upon installation. You know how those new boots are, sometimes you think it's on when it isn't. Again, I appreciate the opinions. Mike
Yes. Built and balanced by Dynothech Engineering in Troy, MI. Good unit. I'm certain it is an engine issue. With the trans disengaged it will still do it. Even parked, with it in gear and the clutch in (to eliminate possible clutch disk misalignment) it will vibrate.
When I got the trans (saturday) I took it apart to check the internals and all, which seemed to be in fair working order, no terribly worn gears, bearings, or synchros. It seems to work well, though it has a noticeable gear whine, not entirely sure why as I'm more concerned with the engine at the time. I'm just trying to help here ... You want to know why your 289 is running rough - And you claim it was perfectly fine before the trans swap- Ok logical thought is something got whacked on install or the new problem showed up with the new trans. You find an ignition issue ( there may be more to discover also and you might have cracked a plug again if it was that easy the first time) and correct this and the symptoms are indeed better. You still have a brand new never before noticed rpm related vibration with a new to you know little about slightly warn and Whiny trans because it wasn't there before this trans went into the car. But that doesn't concern you and you want to chance engine troubles. I wasn't driving it before the trans swap so I'm only going off of what you said - "it was fine before the t5 swap". So the only logical conclusion is that on the day of your swap, where ever you went worked jacked, pryed tweaked while I'm here **x ed, touched, didn't tighten, forgot, bumped, ( get it? Retrace your steps and god help you if you had help) is where the problem lies Or the transmission brought the problem. Perhaps the little 289 wasn't fine before the trans swap and this problem is just more noticeable now, idk I wasn't driving it.
Ok but it was fine before your t5 swap So it is possible you knocked some fuel system sediment loose on your trans swap. Fuel filter should catch it and fuel pressure should show this.
Greatly appreciate the help 31Vicky, I'll take all the berating I can get. That's what's got me is that it didn't have the problem before, and now it does, with the only thing changed being the trans. The fuel filter is next on the list, along with messing with the choke just for argument's sake. I so believe that once that has been attempted my remaining option is to pull the trans and see if the engine runs rough without a transmission hooked up. If not, well, then I guess it's the trans! Logic dictates, right?
Take the guess work out, hook up a few pressure gauge and watch it as you hit the problematic rpm range. Have you checked manifold vacuum with a gauge yet? Even though it runs fine at idle it would be good to get a base line on that as well . The more concrete info you can gather the better. You'll get it running like a song soon enough!
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