What might cause a ticking (from driver’s side head area) that gets louder and louder, and occurs once the car warms up?
I got my carb installed today and fired up the beast! Yay! …and then I spent a while chasing fuel leaks. Wipe up fuel, tighten fittings, crank engine, check for leaks, tighten fittings… until no more leaks. Here I was afraid of stripping out the aluminum threads, but I had to crank on some of those fittings pretty good to get them to stop leaking - yikes!
After that I had it running so I could start messing with all the various fuel levels and idle speeds and idle mixture screws. The initial settings had the engine at about 1500rpm, and it ran like a champ ~ no misfiring, no backfiring, just humming along happy. So then I started doing the initial idle settings and dialed down the main idle to about 1000rpm, and started tweaking the idle mix screws trying to get to a smooth idle (truthfully, I thought it was pretty smooth already). As I’m doing that I start to hear this ticking sound, and then it starts getting louder! I shut off the car, and set my idle mix screw back to baseline (1.5turns open), thinking maybe I leaned it out and it was pinging or something. Fired it up again and no ticking, so I start dialing down the main idle a bit more trying to get it to 750rpm before I mess with the idle mix screws again, when the ticking starts again ~ getting louder the longer it goes. So I shut it down again.
I did some reading and most ticking points to lifters. I pulled my driver’s side valve cover (which seems to be where the noise is coming from) and checked to make sure everything in there was tight and looked good. Everything seems ok.
Some folks mentioned that ticking could be exhaust leaks and that headers need tightened up periodically. So I checked mine and sure enough found a few loose screws.
I thought I would post and see if I’m on the right track or not. I’m thinking that it may be one of several things;
ticking started once it got warmed up, so maybe it is an exhaust leak due to thermal expansion?
Could it be related to my timing? During my carb rebuild I discovered the vacuum port to the distributor was blocked due to the previous rebuilder using an incorrect gasket. So now that the dist is actually feeling vacuum, maybe it is messing with the timing enough to cause a tick due to advance/retard?
I’m also pretty sure I have a leaky head gasket on the driver’s side. Once it was up to temp the thermostat would open. Is there a possibility that this could cause a ticking, due to water flashing to steam? (Note, my radiator isn’t pissing out fluid at all).
In summary, what might cause a ticking that gets louder and louder, and occurs once the car warms up?
Figured I would go for the “old standby” and called mah Dad
He recommended a stethoscope, or the wooden dowel / handle trick.
So when i fired it up today, no ticking, so I backed it out of the garage into the sunshine to idle. Once it warmed up then clackety-clackety! So I put my dowel and ear to the driver’s valve cover… nothing. Put it to the passenger valve cover… clackety-clackety-clack! Huh… I haven’t been in there since I pulled the plugs and removed the cover just to look things over.
Shut down the engine, pulled the valve cover. About that time the Oregon Sunshine had apparently expired, so it started drizzling on me :-/
But, I found the problem…
All the rocker shaft bolts were good and tight, so all I can figure is that when I was putting the valve cover on I bumped a rocker arm enough to shift it off of the valve. From there it worked its way off the valve and unleashed the pushrod. The pushrod slid under the neighboring rocker and was wedged in there. It had also come off of its lifter and was basically stuck in there at an angle.
I loosened the rocker shaft enough to get the pushrod and rocker out of their predicament. I noted that the rocker had been riding on the valve retaining clip and washer for long enough to score the hell out of the retaining clip. I wiped up all the shavings I could find, wiped off the end of the rocker and did a quick visual on the push rod. The rocker itself isn’t galled, but i’m sure it isn’t 100%. The push rod was not obviously bent either.
So I put them back together and fired it up just long enough to get it back in the garage.
Check for a sticky/stuck lifter first. Pull the cover off and turn the engine over by han until that position is on full valve lift. let it sit there for half an hour then rotate the motor over until that postion is back on base circle. grab the rocker and check for lash in the system. If it is really loose the lifter plunger is stuck. if it is just spongy it’s OK. Then I would get the motor warmed up and them check for lash with it on base circle when it’s hot. The lifter might only be sticking when it’s hot.
I still need to verify the pushrods are straight, and do a good inspection of the rocker and spring. Yesterday I did just enough to make sure it wouldn’t “blow up”, and got it back in the garage. So I know the pushrods are not pretzel shaped, at least
Do you think there is anything to worry about on the rocker pad itself? Should I give it a quick “buff” with some emory cloth or something just to be sure there are no burrs on it?
Glass stove top will work but watch out for the wife
Run your finger nail over the rocker pad and valve tip and see if it catches on raised metal. Generally, not a good idea to sand on a rocker arm pad as you can change the profile. it might not look like it to the naked eye, but they are profiled in both direction so the pad is making a point contact on the valve tip. This stops the rocker pad from grabbing the valve tip and bending it while opening the valve.
Ok, pulled off the rocker shaft and rolled the pushrod on the stove (shhh!). It has a very slight bend to it. Not enough to see, even against the stove, but it has a slight “wup-wup-wup” when I roll it. I tested out the other one that it was leaning against and that one is straight as an arrow. Tested out one more, just for personal reference, and it was also straight as an arrow.
Quite a bit of wear on the valve retainer, and some metal flakes here and there :-/
Surface of the rocker and the end of the valve seem fine. Couldn’t feel anything with my fingernail on them.
Ok, off to bed! Thanks again Brian, and I look forward to any recommendations you might have tomorrow
Oh yeah, I plan to take the pushrod in to work with me tomorrow and measure it. I understand it should be 9.59" or somewhere thereabouts?
from the pictures your rocker arm pad and valve tip look fine. Don’t worry about the the mark on the retainer and keeper. that should never cause a problem more cosmetic then anything. The push tube is 9.621" 5/16" any of the aftermarket vendors ahould have one.
Thanks Brian, and yes it has to be a Nikon (although it is a pretty old Nikon)
I saw that Mansfield Mustang has NOS ones listed for a few bucks, so I’ll probably go that route.
Do you think I need to worry about the metal flecks the retainer left behind? Given that the rocker ate that retainer for breakfast and didn’t get nary a scratch I’m guessing the flecks will just wash down into the pan and filter without much trouble.
A Q tip with some grease on it will work also. Keep in mind that oil will go to the oil pump first before the filter. Better to keep the metal flakes out of the oil pump gears.
Mine measured out to 9.5900" (I was very surprised at the accuracy of 40year old manufacturing), from ball end to ball end. Ball size is 0.375".
I found a place that has them locally (Mansfield is closed until Mar 14th).
Is there any reason to replace all of the pushrods? Or is it ok to just replace the bent one?
Well, ordered my replacement pushrod and picked it up last night only to find they received the wrong one (order slip was right, but number on the part did not match).
And then last night I figured maybe I better check all the others just to be sure. And of course it turns out about half of them are tweaked just a little bit. One or two were just as bad as the one I planned to replace.
So I changed my order this morning and I’m just gonna get a full set to put in. Seems like the right thing to do.
You can just replace the bent one.