Engine Question

[case12]

I am not as good at engine work as I am at detail work on my GT/CS. So, I have a new engine problem to ask the group. My GT/CS (289) started running very rough - almost shaking the engine off the mounts, especially under acceleration. I checked around and found where the problems is, but not the problem itself - the number 1 cylinder appears to be the culprit. The odd thing is that when I take the plug wire OFF number 1, the engine runs smooth - when I put it on it runs rough. I have switched wires and plugs and get the same effect (the plug is a nice tan color). As soon as I put the wire to the plug the engine starts shaking. What may cause this? Valve settings (the valves are noisy)? Worn out cam? I have a mustang engine buddy coming over to help me out Sunday, and thought we could use a few ideas. I need to have her running good as show season is starting up here soon. Casey

 

[Mustanglvr]

Maybe its the plug wire. It could be bad. Or, I know the wires are supposed to be on the plugs in a certain order, maybe that has something to do with it. I`m sure you`ve already checked all that. I`m just coming up with a few guesses for ya. Rhonda

 

[case12]

Rhonda, thanks. We have replaced plug wires and checked the firing order. Maybe it is timing or valve settings? The shop messed with both of these last time I had it in. BTW, it has Rousch heads. (anyone have these on their C code?). Casey

 

[coloradoHCS]

Case12, vibration at the engine could be a number of things both internal and external. Here are my thoughts:
1)Eliminate the plugs and wires. If the plug is tan it is a good indication that it is firing properly.

2.Timing chain and or valve timing could be the cause. Check to see that the valves are closing on the compression stroke. Pull the spark plug and plug the hole with your finger. Jog the starter and the compression should push your finger away at TDC of the compression stroke.

3)If timing is dead on and the pressure is not there during the compression stroke look for a flat cam or valve adjustment/failure. These may cause vibration.

4)Sometimes the rubber ring within the harmonic balancer will have spun. This will throw the balance of the engine out, especially at higher RPM. Visually inspect your balancer for cracking or separation. This is a common cause of high vibration in engines when all is correct internally.

5)Does your car have an auto or a manual tranny. If is is manual sometimes a bad flywheel can cause vibration. I think this possibility is remote but worth considering.

6)I can see no reason why the heads should be causing this problem. How long have they been on the car? If they are a new install and this did not occur prior to their installation then obviously they are "suspect one" but I doubt it.

Case, I would start at the balacer inspection first, then the timing to see if it is electrical (timing, plugs, points if present, etc) then look at internal mechanical (valves, cam, crank-ugh!, or flywheel). I hope this helps, Mark.

 

[jk89cat]

also check the cap , it could be arcing when it hits that cylinder . i would also look at the balancer before you try to adjust timing

 

[case12]

Great advice. Nice to have some other ideas. Thanks!

BTW, it is an automatic and was running fine until the shop messed with the valve setting (to try to get them quiet) and the timing. It is not just vibration - I can hardly keep the engine running under load when idle (once I get it going and dont accelerate, it is ok). When I take the wire off number 1 plug, it smooths out and is drivable. I will check the balancer, timing, valves and cap.

I dont think the Rousch heads have anything to do with it (they were working fine before). I just mentioned them because I found a different problem with them: I cant get a wrench socket around some of the spark plugs because the stock exhaust just ever so slightly overlaps where the plug goes and is in the way of a using a straight wrench socket. Any ideas on how to get plugs out when the normal wrench socket cant get in there? Thanks, casey

 

[coloradoHCS]

Casey, as far as the rough idle. With the further info it sounds as if the timing is not advancing. What condition is your chain in? Also check your advance mechanism, either vacuum or mechanical. I wonder if the chain slipped a gear or two and has taken the timing beyond the limit of the distributor adjustment. I have had this happen where I could not get full advancement in the timing at high RPM and experienced rough running due to a bad chain. It ran fine at idle. A loose/stretched chain can also cause this even if it is in the correct position. These engines left the factory with a nylon gear. these can shear a tooth or two and give you the same problem. Throw in a gear drive and it will sound like a supercharger!!

On my 454 Vette with Hooker headers I had to take a standard deep well socket and turn it down on a lathe to get adequate clearance. Some auto performance stores will sell a "thin wall" socket for this application.

If you can supply further symptoms we may be able to isolate it further. Mark.

 

[GTCS95616]

Check for a carbon arch on the inside and outside of the distributor cap.

 

[case12]

Thanks guys. I will check these things on Sunday and let you know (out of town right now). I can hope it is the timing setting - the guys at the shop messed around with this a lot.

As for the spark plug access problem - I will check the shops to see if they have a thin wall socket. I checked a few of mine and one is pretty thin, but still wouldnt fit.

As always, you guys are a great help and I will let you know how it goes. Casey

 

[rvrtrash]

One last thing that probably isn't the problem but easy to check. If someone put in a later dual advance distributor and have the vac. lines backwards, it will want to die at idle.
Steve

 

[case12]

Well, it wasnt the plugs, plug wires, or timing. (What do you all use to set timing on a 289 - 12 degrees TDC? - does having Rousch heads make a difference?). Next look is timing chain and valves. Casey

 

[case12]

[quote author=GTCS95616 link=board=1;threadid=1605;start=0#msg9748 date=1114144197]
Check for a carbon arch on the inside and outside of the distributor cap.
[/quote]
checked it and inside is clean. It has electronic ignition added.

 

[case12]

[quote author=ColoradoHCS link=board=1;threadid=1605;start=0#msg9732 date=1114100492]
Casey, as far as the rough idle. With the further info it sounds as if the timing is not advancing. What condition is your chain in? Also check your advance mechanism, either vacuum or mechanical. I wonder if the chain slipped a gear or two and has taken the timing beyond the limit of the distributor adjustment. I have had this happen where I could not get full advancement in the timing at high RPM and experienced rough running due to a bad chain. It ran fine at idle. A loose/stretched chain can also cause this even if it is in the correct position. These engines left the factory with a nylon gear. these can shear a tooth or two and give you the same problem. Throw in a gear drive and it will sound like a supercharger!!

On my 454 Vette with Hooker headers I had to take a standard deep well socket and turn it down on a lathe to get adequate clearance. Some auto performance stores will sell a "thin wall" socket for this application.

If you can supply further symptoms we may be able to isolate it further. Mark.
[/quote]

I think we are down to the chain or the valves. I could not turn the distributor far enough to get it to idle smoothly (and I was at 20-30 degrees TDC!). Stupid question - if the chain slips, is it possible for it to slip back into correct position? Will let you know what we find next. Casey

 

[rvrtrash]

Casey, if the timing chain slipped, it won't go back to the correct spot on it's own. The gears and chain will have to be replaced. Before I did all that though, I would check the electronic ignition. Is it a Petronix type system? I've heard of the conversions failing, so if it is, put the original points, condensor, etc. back in and see if the problem is solved.
Steve

 

[coloradoHCS]

Casey, I agree with Steve the chance of the chain slipping back to its original position is not likely. The cam and the crank would be out of alignment and there is little chance of these again being in their proper alignment without taking the chain off and actually moving them into position. You will see the alignment marks if you decide it is the chain and remove the cover.

How was the balancer...good condition?

Certainly check the ignition prior to getting into the chain.

A simple way to see if the valves are closing at TDC or just before is to remove the No. 1 plug and put your thumb over the hole. Remove the cap and note the position of the No 1 wire. Jog the engine and when the rotor comes around to the No 1 wire position your thumb will feel the pressure of the piston coming up with valves closed. It may take 2 full rotations to check this because one rotation will be exhaust and that valve will be open, therefore no pressure as the piston comes up. I have used this on many occasions to check the valve timing.

The HCS I purchased from Bish lost 2 teeth and had very similar symptoms to your car. I did this test and found I was getting pressure at the hole way prior to ingnition with no way to adjust the distributor. I then found two broken teeth on the factory original nylon gear. New timing set and the car runs smooth and is very reponsive. I believe the teeth boke when I retuned for altitude after bringing the car back to Colorado from Michigan. Sometimes changes in the timing will stress old parts and break the weakest link. The teeth of the cam timing gear are designed to be the weakest link.

You can purchase a push button starter with cable from the auto parts store so you can do all the jogging from under the hood. (disconnect the coil wire).
Mark.

 

[case12]

Well, it got messy. We adjusted the valves and it just kept getting worse. We have to adjust them to almost no slack to keep the 289 running. Timing is ok, timing chain is ok, distributor is ok. My engine buddy is now convinced that it is the Rousch heads because the push rods are getting grooves cut into them and the rocker arms are getting hit pretty hard.

So, he called his FORD racing buddies and they gave me 2 options. Replace the valve train from stock to an appropriate racing valve train (the prior owner used the stock valve train with the new heads) to go with the Rousch heads ($1000), or put the orignial heads back on. Fortunately I got the original heads from the owner when I bought the car.

I want to take the car back to orgininal so, that is the route we are going. So, next week we send the original heads to the machine shop and also get the hardened seats for the valves.

Sounds odd that this would be the cause to me. I cant believe the heads are causing all this, but these guys are mustang experts (and friends). I will let you know how it goes. Casey

 

[PNewitt]

Sorry to hear about the "de-tuning" of having to yank out the Rousch heads.

So, you couldn't replace the pushrods only? I'm sure you can get a lot for them, if you put them on the market.

Have you thought of Ededbrock heads--perhaps later? I can't remember if you mentioned it--but if you use a Cobra intake (302?), I think you'll be happy.

In any case, chalk it up to experience. Make big plans for that Westlake-Gurney heads--total weber setup for next time, OK?

At least you didn't get into a gross engine experience like i did. In my "starving artist dayz" in San Diego, I had to park my car up on a friend's curb to change the freeze plugs, and the idiot neighbor turned on his sprinklers..here comes the water down the gutter...I was wet, and greasy under the car...

NEVER AGAIN! Geesch!.

Paul N.

 

[case12]

My engine buddy (who consulted with his FORD racing buddies) said that the correct valve train would be $1000. (But your question has me wondering if just the push rods could be replaced to get the correct clearance??). Anyway, he knew I wanted to take it back to original eventually, so we thought it best to just machine the original heads (harden the seats for unleaded too) for less than $1000. He thinks the performance will be about the same. I have the original intake and carb too, but he suggested keeping my Edlebrock aluminum intake and Edlebrock carb as these are very easy to change later. I am not into racing or performance on the GT/CS - I am more into originality. My buddy said I could clean up the Rousch heads and sell them on eBay for a nice price. Casey

 

[case12]

Paul - like your story getting wet in the gutter.

Many years ago, I was working under my Chevy Citation (dont laugh - needed it for the family) in the driveway. It was on an incline driveway, and I didnt have it blocked. My then 3 year old (who is 18 now) was playing around inside the car while I was working on it and pulled it into neutral. The car began rolling down the driveway and I was under it!. The rear tire rolled down onto my arm and chest and I was pinned! (Thank God it was not my neck!) A construction worker building a house across the street heard me yelling and came and pushed the car off me. I had tire tread imprint bruises on my arm and chest for a few weeks after! Needless to say, there are about a dozen lessons learned in that story. :-[ Casey

 

[rvrtrash]

Let's see. Should I tell the story about changing a TR-6 transmission in a parking lot in the pouring rain or the one about being pinned up against a Forest Service gate when my Fairlane dropped out of park into reverse while I was standing behind it? We must really love these metal beasts to put up with the abuse they give us.
Steve