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Vindictive

Chasing a Noise

45 posts in this topic

I've had a noise going on for a while now that I thought was an exhaust leak up near the exhaust manifold on the passenger side. Some time before I got the car somebody did a real hack job of installing a dual exhaust system that had terrible welds that leaked at just about every joint. I've changed the leaking flange gasket and spent some time tracking down and welding up as many of those leaks as I could find at the joints. The noise is still there, but the exhaust leaks are gone. Checked for an intake leak as well, found none.

 I've had some slight hesitation issues as long as I've had the car that I attributed to a bad vac advance, but I replaced that with a good unit last week. I changed points, condenser, dist cap, rotor, coil, plug wires, and plugs (7-8 months ago). And now it actually seems worse. It's now hesitating worse during acceleration and popping through the pipes a bit now as well. My first inclination was that it was ignition/timing related since I replaced everything. So I re-checked everything. I put the old coil back on to make sure that there wasn't an issue with the new one. I've set timing and verified that both mechanical and vac advance are working properly using a digital timing light to check advance curves (initial 5 degrees [email protected] rpm, total 30 degrees @ 3600 rpm, vac disconnected for both). Fuel delivery crossed my mind, but fuel pressure is good, filter is clean, carb was cleaned and rebuilt earlier this year. I checked the vac piston/metering rod assy. to make sure that it was not binding and the vac piston spring wasn't broken. It moves freely. 

I've been scouring the forums looking for somebody with a similar issue. Then my mind wandered back to that psst, psst, psst noise that sounded like an exhaust leak. This morning when I got to work I pulled the rocker cover off and that noise was a whole lot louder and seemed to be coming from the back half of the motor. Still sounds more like a loud exhaust leak rather than a tap. I pulled all the the plugs from that head and the plug in #5 definitely looks different than the others. Appears lean. The electrode is white and there's virtually no discoloration on the porcelain insulator. I didn't notice any slop in the rocker arms that would indicate valve lash. I still feel like I need to pull the intake off and have a look at the lifters, pushrods, and cam lobes to figure out where the noise is coming from. Have not checked compression yet. Anybody have any thoughts/recommendations?

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Time to check compression.  The back popping could be from exhaust or intake valve not seating well. Providing timing and wire/firing order is correct.  You checked all of that.      Possible bent valve.  For now, pull the rockers and check all the push rods to assure none are bent.  Be careful here because sometimes the lifter will come up with the push rod and not stay in the bore above the cam.  If that happens the intake needs to come off to put it back in the bore.  Been there and done that.  Lamar has been down that street as well. ;(        

 

PS. Second plug from the left looks new and not burning much of anything if at all.      The others appear normal.      

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That's the plug that came out of #5. Been in there for months, and I drive the car just about every day. I agree though, looks almost new.

Leaving the car at work tonight. Wife and kids out of town and I have some projects around the house I gotta knock out while they're gone. Will check compression then pull the rockers and pushrods if I can get away for a little while. 

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Well, almost no compression in #7.  The needle barely moved up to like 15psi while cranking but bled off almost instantly.  Looks like I'll be pulling the head.

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If it turns out to be catastrophic, I've got a 54 322 that was quoted as "running great when pulled" I can let you have cheap. Pm if interested. 

And hey I'm just down the road from ya, generally everybody is 500 miles away...

Vindictive likes this

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Lamar, I'll keep that in mind. I've got the exhaust manifold bolts saturated in PB Blaster right now. Will probably give them a few days to soak before I attempt to break them loose. I'm expecting to find a bent or burned exhaust valve, hopefully not something in the lower end, but we shall see. 

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Surprisingly I've never had any problem getting exhaust manifold bolts out of 322's, go ahead and give them a tug after work.

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I recommend a leak down test before pulling the head.  This will help determine if the rings are toast.  Let me know what you find.   The exhaust manifold bolts on my 264 came out without issue.  Hopefully just a valve went south.

 

   

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Here is my adventure chasing a noise and smoking.  Pulled heads. Found OPEC was running through the heads. Clanking valve.  Replaced rings.   It may help you with your engine.  Of course I will be around to answer any questions.  It was not a hard job.  Be mindful of the temp gauge plumbed to the driver side head.  Soak the connection to the head.   

 

 

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Chris, I'm actually pretty familiar with your thread. I've probably read thru it at least twice while looking for guidance on my issue. I don't have a leakdown tester but may look into seeing if anybody loans them before I pull the head. I did the compression test dry and then wet without any change in psi. This car never smokes, there's a little lifter noise on start up when it's cold, but it goes away in a few seconds.  I've included a link to a short video I took with the valve cover off engine running. You can really hear the psst-psst-psst noise pretty clearly. It was much quieter with the valve cover on, sounded like an exhaust leak. I did notice a couple of rockers didn't look like they were flinging much oil. 

 

 

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Definitely huffing and puffing.  If you did a dry and wet with no change I suspect a valve burnt/cracked or hole in piston.     I noticed at about the 10 second mark on the video what appear to be a loose bracket that holds the rocker shaft to the head.  Just at the base it looks like it is pushing oil out and sucking it back in with every open and closing of the valves.  Are the brackets tighten to the correct foot pounds? Could just be the lighting reflecting off the oil.     Are you certain there are no vacuum leaks in and around the intake?  Specifically at that cylinder.  If not, remove the intake for inspection.  More than likely the head will need to come of as well.  Mine was doing a odd tapping and not really a puffing sound.  At the end of the day...heads came off and went out for rebuild.  I suspect you may be going that route as well.  Hopefully no hole in the piston. :( 

 

Concerning the oil.  It kind of just drips out of the shaft area where the rocker rides.  Increasing RPM some oil will start flying.   I never see much on mine at idle.   We know oil is present and pumping though. 

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Must have just been a reflection on the oil. Bolts were torqued properly. I pulled the rocker shaft and disassembled yesterday. Shaft has some wear, but not so bad that I'm inclined to replace it right now. Typical wear on the ends of the rockers too. I checked for intake leaks, sprayed carb cleaner everywhere around and under the intake and could not get the idle speed to budge. I'm gonna pull the head as soon as I get a chance and see what's going on inside. Hopefully no hole in the piston. I feel like the plug would look sooty or oil fouled if there was, but I've seen some crazy issues where the symptoms you expect to see don't show up. I'll find out soon enough, one way or the other.

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No vacuum leak eliminates one possible cause.   The plug looks like it fires every now and then.  Dark coloring/black wet and or dry deposits are either vacuum leak, low compression or timing off.   Your suspect plug has some light dry deposits.   You know there is very low compression.  The sucking air noise present in and around the suspect  cylinder.    

 

Tip:  the top radiator hose crossover manifold that is bolted to each head, after removing the 4 securing bolts lift up the water manifold as there is a rubber O-ring on a small metal pipe that feeds into the top of the water pump house.  

 

Tip:  There is one head bolt on the passenger side that has a threaded portion that secures the generator bracket.  Take a picture of the location in the head so you can remember where the odd ball head bolt goes when reassembly begins.   Thankfully Father Buick unknowingly provided me that tip when he handed me the head bolts in Allentown stating, "I even has the head bolt for the generator bracket." :)             

 

Concerning what is found with the head and it requires rebuild or replacement let me know.  The pair of heads I purchased from Father Buick I have had rebuilt as stand by for me or someone like yourself. Should be done by know.  I did not rush Bill Coleman(Coleman Speed Shop) as I had a fresh set ready to do.  I'll need to check his progress.         

 

 

   

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Yes sir, that is a problem.   What are the plans? 

If you plan on having the heads rebuilt, I have a set done and ready to go.  As noted a few posts back.   Came off a 264(Father Buick).  The others can confirm the 264 and 322 heads can bolt on either block.  

 

How was compression on the other cylinders?   

   

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Not sure yet. Need to pull the valves out and look at the seats. Then figure out who's got a good reputation locally and see what a valve job will cost. Compression was a little low in 1&8, but not terrible. I may re-ring. The rear main rope seal needs to be replaced, so since the oil pan is going to be off anyway I'll probably go ahead and do it.

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The heads I purchased from Father Buick,  to be completely done at Coleman's Speed Shop, ran $950.00.  Bill Coleman understands the nailhead and had all the right answers when I asked him about rebuilding Buick heads.  He winced when I told him someone put hardened seats in my 54's heads.  Then Bill directs me to a fella up the road who needs to get rid of a 55 Buick.  I go to look. In his garage are two hot rods with nailheads that Bill Coleman built for him.  Anyway, the 55 had a rare power brake unit. Fella from BCA came up from Charlotte and purchased the drivetrain/power brake unit. 

Consider the ring job. If your compression was good on all cylinders but #7 perhaps leaving it be is best.  If you go that route I did get rings and complete gasket set from Martins.  I did it all while motor in frame.  Not fun but can be done.

 

If anything, replace the one valve.  The other are working just fine.  Drive it!

 

  

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19 hours ago, Avgwarhawk said:

replace the one valve

Unless you are going to do a complete rebuild just do the one valve.  Rebuilding heads around here are about $350.

Valve grinding compound a replacement valve.

Things you need to watch for:  

1) Valve stem height: 1.525 to 1.550 measured (in inches) from valve cover rail to valve stem tip.  Or with a straight edge set the same as the others.

2)valve stem clearance in guide:  (don't worry about this unless you replace the guide, but check for sloppy fit)
0.0025 inlet
0.0030 exhaust

 

 

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What's the trick to getting the temp sensor bulb out of the driver side head? The retainer nut backed out fine, but the bulb didn't want to budge. I didn't want to break it so I didn't force it. Left it soaking in some pb blaster.

 

 

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There is a freeze plug on the back of the head that is probably thin and about to fail, just behind the trottle linkage brace.  If you can poke through that, you can get to the side of the temp bulb and get it to wiggle free.

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12 hours ago, Vindictive said:

What's the trick to getting the temp sensor bulb out of the driver side head? The retainer nut backed out fine, but the bulb didn't want to budge. I didn't want to break it so I didn't force it. Left it soaking in some pb blaster.

 

 

Let is soak as long as you can.  It is a fragile item.  Doug has a really good plan if all else fails.  Remove the freeze plug.  Soak it from the backside.      

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11 hours ago, Father Buick said:

There is a freeze plug on the back of the head that is probably thin and about to fail, just behind the trottle linkage brace.  If you can poke through that, you can get to the side of the temp bulb and get it to wiggle free.

Since you already have the head off,  remove the freeze plug.

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Willie, I haven't pulled this head yet. I've got the other one off, but haven't pulled the headbolts out of this one yet. I'm guessing there's enough slack in that temp line (once the retainer clips are removed from firewall) to un-bolt the head and re-position it to a more suitable position for knocking the freeze plug out??? 

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3 hours ago, Vindictive said:

Willie, I haven't pulled this head yet. I've got the other one off, but haven't pulled the headbolts out of this one yet. I'm guessing there's enough slack in that temp line (once the retainer clips are removed from firewall) to un-bolt the head and re-position it to a more suitable position for knocking the freeze plug out??? 

Ok, so I guess you are going to rebuild both heads.  Again, if it ain't broke don't fix it.

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