Ticking Sound Coming From '67 390, But Goes Away

[Agar426]

I've got a '67 Mustang Fastback with the 390/C6 combination. ~135k miles, but was rebuilt ~20 years ago, with only about 10k miles since the rebuild.  I only use it as a weekend driver, maybe occasionally to work.  Lately, I've been getting a ticking sound coming from the engine, which increases as the RPMs go up.  It's a single tick, not a rattle, so I am thinking it may be one of the lifters?  Maybe the fuel pump?  I am not a very good mechanic, so I am merely guessing.  Here's the weird thing....it doesn't do it at start up, it starts after I've been at operating temp a while.  But, after a few minutes, it goes away.  Stops completely.....

Here's the thing.....if it's something major, I don't want to spend bad money before I spend good money.  The car runs fine, but it's not what I would call a strong engine.  It runs out of steam around 4,000 RPMs, oh, it makes plenty of noise above 4k, but it doesn't do anything exciting.  Point being, I don't want to spend $X to fix a problem, when $2x will get me new heads, new intake, and maybe headers. 

So, two questions:  1)  Any thoughts on what it might be, and why it comes and goes?  2)  If it's major, and in the valvetrain, do I pull the engine and do a full up rebuild, or even stash the engine (numbers matching), and replace with another 390 long block?  Or, do I just make the repair and drive it around happily?

[jayb]

It would be good to try to locate the source of the noise, if it will make it with the car running but stopped.  My old trick was to take a big screwdriver, put it against the valve covers in various spots, and then put your ear right up against the plastic end of the screwdriver and listen for the noise.  Go along each valve cover and see if you can localize the noise.  Also put the screwdriver against the fuel pump; if the fuel pump spring breaks, it will make a ticking sound just like a lifter or rocker arm.

If you can localize the noise under one of the valve covers, pull the valve cover and see if you see anything unusual.  Post some pictures here, we can help if there is an obvious problem.

Since the noise comes and goes, I'd bet on a lifter or the fuel pump.  There is no telling why these noises are intermittent but sometimes they are.  The fuel pump fix will be cheap, lifter fix, probably not if you have to pay someone to do it.

Sounds like you would like some more power from the engine, so if it does turn out to be a lifter, I'd pull the motor and put it away, get yourself a 390 or 428 block, add stroker kit, heads, intake, headers, and build the engine you really want.  Good luck on solving the problem.

[Pentroof]

I know Jay was also thinking exhaust leak, but when you said the noise then goes away, it threw him off the scent.
I still wouldn't rule out an exhaust leak. Stranger things have happened.

[preaction]

Try changing changing your oil with a different brand oil, you have varnish on and in your lifters from lack of use.

[plovett]

I may get crucified for this but........I would put a can of Seafoam in the crankcase, drive it 50 miles or so, and change the oil. 

JMO,

paulie

[jayb]

I know Jay was also thinking exhaust leak, but when you said the noise then goes away, it threw him off the scent.
I still wouldn't rule out an exhaust leak. Stranger things have happened.

Actually, I hadn't considered that because it sounds like there are exhaust manifolds on the engine, not headers, but I agree an exhaust leak would be a possibility.  They can sound like a tick, or a knock in some cases.

[unclewill]

My fresh 427 in the classifieds will bolt right in...just sayin'
 

[Agar426]

Thank you all for the suggestions!  My apologies on the late response, as I didn't get a notification.  I usually check at least once a day, but got caught up with household chores.  I am definitely planning on freshening the fluids.  I typically drive it to work for a week straight about once every month in the good months.  During winter, only if it's dry out.  It gets use, just not daily use.  The current oil in the crank case only has about 1,000 miles on it, but...it is a couple years old, so I will get on that right away. 

It is a correct assessment that the engine is still running the factory exhaust manifolds.  I will investigate that as well.  Part of me wants it to need to be pulled, but the other part of me can't afford it at this time.

I would LOVE a stroker kit.....nothing crazy, but I want at least 500 lb ft.  Don't care what the horsepower is, as long as it's at least 475......although over 500 would be great, but not at the expense of driveability.  I should mention that I live at 7400 ft.  I actually have a thread on here about 3 years old asking questions about the build.  Was expecting a decent cash out from work, which I got, but I put the money into the house instead of the car.  Dammit!   That being said, I love reading any and all input on FE builds, so keep it coming!  My goal, as I stated is no less than 500 lb. ft,  good driveability, fuel injection (off the shelf if they will work ok....Atomic, Sniper, FiTech, etc.), and hopefully a swap to a 5 or 6 speed from the C6.

[machoneman]

At 7500 ft. you've already lost a ton of hp and torque. Wallace has a well-known racer formula for the estimate of loss by altitude:

 http://www.wallaceracing.com/braking-hp.php

Talked to some Pro Stock racers years ago, some of whom slipped racing in Denver's area NHRA track. Re-jetting the dual Holley Dominators was a bitch from near sea level tracks as most lost IIRC 3-4 tenths e.t. even on 1,300 hp engines. 

[shady]

my vote is exhaust leak, especially if you have gaskets between the head & manifold and or still have the heat riser spring at the right side doughnut.

[Agar426]

my vote is exhaust leak, especially if you have gaskets between the head & manifold and or still have the heat riser spring at the right side doughnut.

I'm running an open element air cleaner.  The OE emissions gear is in my father-in-law's shed.  The sound itself, audibly sounds "hard" as if two objects were hitting each other. 

[plovett]

I would still try the Seafoam.  As for altitude, wow, that's way up there. 

I think anything that you can do to increase the effective compression ratio will help it feel stronger.  When and if you need to rebuild the engine, you might go with a considerably higher compression ratio than would normally be considered.  If for some reason you have the heads off, you could mill them for increased compression ratio, and/or use a thinner head gasket.  I guess I don't know what your compression ratio is now, but I assume it's not terribly high?

Also, you could advance your cam to increase the effective compression ratio fairly easily. 

And headers are the best performance modification to pretty much any vehicle.  You'll gain low end, mid-range, and high end power.  When you're up as high as you are you need any advantage you can get.

JMO,

paulie

[TJ]

I used to have a 390 that developed and on/off tick.  Turned out to be a slightly bent push rod rubbing the valley splash tray...dang near drove me up a tree trying to find it.

[Agar426]

Looks like a bad lifter.....damn!  Now the subject changes, should I start a new thread?

[preaction]

At only 500 miles a year over 20 years its not a bad lifter its dirty. Reread post #4.

[machoneman]

2X to Jay's post near the top. But I use a cardboard tube (long one, see wifey's Christmas wrapping stocks for one!) instead of the screwdriver trick. 

[Agar426]

Agreed!  My mechanic said he wanted to flush the oil, get it up to temp.....seafoam, flush again.  I would love to tear it down....actually mothball the numbers matching block, and drop in a stroker FE.  Not a high zoot one, just a clean, simple strong 445 combo that will "act" like a big block should.  That being said, I have other projects that I need to wrap up, so if this needs more than the flush treatment, I will likely go with a simple repair, which the shop shows on the computer as 4.5 hours of labor, plus the cost of the gaskets and lifter set.  The question becomes...since the intake is coming off anyway, does it make sense to install a Performer RPM, or will the difference in performance be so negligible without a combination of upgrades (heads, cam, headers), that it makes the new intake an expense without much benefit?

[Dot Heton]

I had a dipstick touch the crank on a 390 until I tightened the mounting bolt. It made a soft ticking sound.

[jimeast]

My Yukon w/8.1 had an exhaust leak from a broken exhaust manifold bolt.  Made a ticking sound like a lifter, but would stop once it warmed up.

[TorinoBP88]

I had something similar in my old 390, I thought it was a bad lifter. Turned out the rocker end of a pushrod had gotten funky.  I sanded it smooth and turned it over and reinstalled it. No more tick.

In the end the cam bearing clearance was gett larger, allowing rear lifters to run to lose so the were hammering rockers a little. I limped it along for a few more years with Valvoline 50w racing oil.