1966 Deville lifter tick

[austingta]

My 66 DV Conv developed a tick in the upper engine the other day. It doesn't do it at all until the engine warms up a bit, and then it does it all the time. It is RPM based for sure, and the car still runs great, as it always has. It is pretty loud; at cruising speed it's the only thing you hear. The car runs cool all the time, and there is no miss or loss of power at any RPM that I can feel.

Are the rockers mechanical (adjustable) or hydraulic on my 429?

Since I have no miss, can it be so simple?

TIA

Frank in Austin

[Otto Skorzeny]

Are you sure it's a lifter noise? Lifter noises generally are louder when cold and quiet down or go away when hot. Generally.

It could be an exhaust leak caused by a bad donut gasket or manifold gasket. Maybe a cracked manifold.

[austingta]

I don't think so... it's a loud tap tap tap...  I can probably take a video of it and post a link to it. I'll check into those possibilities though. Do you know if the rocker arms are adjustable on a 429?

[Dave Shepherd]

Determine which side, pull the rocker cover off and check for a loose rocker arm, yes hydraulic lifters, the rocker arms and supports could be worn also.

[35-709]

Those are hydraulic lifters, once adjusted upon engine assembly they should require no further adjusting.  It is possible that a rocker arm nut has come loose (although improbable), if so follow the shop manual procedure to re-adjust it.  They are not adjusted like a mechanical lifter.
Having said all that and considering the engine in question, I would have to agree with Forrest.  A cracked manifold (exhaust, or intake at the center left or right where the exhaust passes through) or leaking exhaust gasket sounds very much like a noisy lifter and is what I would be looking for first based on past experience with those engines. 
Geoff N.

[austingta]

It sounds pretty ominous to me...

Here it is:



It could be fuel pump, maybe water pump... it's not exhaust, I'm afraid. I think I can hear a knock to go along with the tick...  It's weird that it still runs perfectly though.

Thanks for all the help... I may need a lot more before this is fixed.

[Chris Conklin]

Not sure how you eliminated the exhaust as the culprit, sure sounds like an exhaust leak to me. Not uncommon, each port is gasketed and can be a source.

[Otto Skorzeny]

If you think it's a water pump or another accessory, just take off the belt and start the car. You'll know immediately whether that was the culprit. I doubt it's any of those, though. 

Take a 3 foot piece of garden hose and use it like a stethoscope to better isolate the source.

[David King (kz78hy)]

I vote for exhaust.

David

[35-709]

Sounds like it could be exhaust to me too.  But that knock is rather ominous.
Geoff N.

[Dave Shepherd]

Again, to track any valvetrain noise the valve covers should be off and any loose rocker arm would reveal the suspect component.

[Dave Shepherd]

This am I rebuilt the booster on a 59 Seville, this PM I am doing brake work on a 59 Coronet, tqlk about shifting gears, I had a time out to switch the gears.  LOL

[P W Allen CLC# 20193]

That sounds like a lot more than valve train or exhaust noise to me. Sounds like a knock is associated with it when the throttle is blipped. I had a 67 Ford years ago with the same type noise. Turned out to be a wrist pin. I hope not! Removing the belts and valve covers is a good idea. I would do it to narrow things down. I would not drive it on the road until you pin down the source of the noise. Good luck with it.

Paul

[austingta]

I would be a nice winter project to put the engine compartment right. It is not very pretty right now.

[Steve W]

Even WITH the tick it will still run fine...for awhile! And then....bang!
(See, what bugs me is the knock thats associated with the tick.)
You are getting great advise from these guys when they tell you to pull the valve covers and have a look.
That's where I would start. It sounds a bit worse than a simple exhaust leak, IMHO.

[P W Allen CLC# 20193]

I am prepared for the worst, a complete long block rebuild. The car deserves it. I think it's original at 120000 miles. It's new to me so I don't know what kind of care it's had.

Yes!! Absolutely worth it. My mother used to have a 66 CDV. Wonderful car. If I had the room. I'd have one myself.

Paul

[Rod Dahlgren #19496]

429 engines have the oil pump in the timing cover. These pumps are know to wear out and loose oil pressure. The FIRST thing that is damaged from LOW OIL PRESSURE especially in the 429  is the cam bearings. When the cam bearings go, the oil pressure to the lifters drops. First sign of loss of oil pressure is the lifter noise------------  Put an oil pressure GAUGE on it and see what you have. But with all the noise I hear, you need to bite the bullet and rebuild that engine. But be SURE you get that oil pump back in shape.

One more thing, running a 429 with valve cover off makes a HUGE mess! Oil all OVER the place..

[austingta]

I installed an Auto Meter oil pressure gauge today. Upon cold start, it reads 28. Rev it up to 3000, it reads 30 or so. Wail til it is totally warm, it reads 27. There is very little variance in the oil pressure.

That cant be right, can it? On my Buicks, the oil would read 60 or more cold and fluctuate failrly significantly between idle and cruise RPM.

Argggh.

[P W Allen CLC# 20193]

I installed an Auto Meter oil pressure gauge today. Upon cold start, it reads 28. Rev it up to 3000, it reads 30 or so. Wail til it is totally warm, it reads 27. There is very little variance in the oil pressure.

That cant be right, can it? On my Buicks, the oil would read 60 or more cold and fluctuate failrly significantly between idle and cruise RPM.

Argggh.

Normal Oil pressure is 30-35 psi for the 429. Check out the link below for engine specs.

Paul

http://www.carnut.com/specs/gen/cad60.html

[austingta]

Thank you for that excellent link. My oil pressure being right on spec if very encouraging; time to go get that stethoscope and see if I can pin down this noise.