This goes back a while, so bear with me as I explain everything.

This past fall, I picked up an AOD trans to put in my '86 F-150 with 351W. The reason was the rpms on the highway (3000 at 65-70 mph), and to get the gas consumption down. Once the trans was in, I noticed the engine didn't have as much torque down low when in overdrive and was kind of struggling. Decided to put a better cam in.

Picked up a Comp Cams 35-230-3. 250/260 duration and .461/.464 lift. Power range 600-4800 rpms.

Put the cam in, did proper break-in and noticed a loud tick (engine was quiet before this new cam). Took it for a ride and this happened : https://www.ford-trucks.com/forums/1...with-pics.html

After the valve guide was fixed (with new valve and push rod), I installed a new lifter in that location. It made no change. I took the lifter I pulled out and broke it down to inspect it and found nothing wrong with it.

After fighting it for a while, I decided to put the old cam and lifters back in. The ticking was quieter, but still there.

Finding out how cobbled this thing was, it was decided this engine wasn't worth the time or money to make right. So, I picked up a running core to rebuild. Got it properly rebuilt, together and running. Now, there's a ticking in the valve train. This is the same NEW cam and lifters from the old engine (only had a couple of miles on them, and properly broke in). The cam, lifters, oil pan, intake were the only things swapped from engine to engine. The cam lobes and lifter faces looked really nice when installed in the new engine.

For the new engine, All of the tolerances were on the low side so I know all the machine work was done correctly. Different block, different heads, rockers, valves, springs, timing chain, pistons, rods, everything that wasn't listed above is different, which makes me believe it's something with the camshaft.

Does anybody know of anything to check that I may have missed? One thing I was thinking of doing was taking lift measurements with the dial indicator set at the rocker tips and compare cylinder to cylinder. Kind of stuck on where to go next and really don't want to pull a fresh engine apart if I don't have to.

Adding: When the new engine was first fired up, there was a really loud ticking sound, which sounded like the flexplate was hitting something. I was leaning over the engine and put my hand on a valve cover and the sound changed. Pulled that valve cover to find the rocker was just barely kissing the baffle inside. I "clearanced" the baffle and that sound was completely gone.

 

Two thoughts: First, a bad lifter or rocker arm. Second, how about the fuel pump? Could it appear to be from the valve train?

Can you use a stethoscope or some such to zero in on where the sound is coming from?

 

I would have to go with Gary on a bad lifter.
If I read the 2 posts right both cam/lifters were used with the tight valve/guide and if so that hurt the lifter.


If you are sure the cam(s) lobe on that one cly is good I would replace the lifters. Yes all of them as I don't think you can get just 1 but you have to break it the cam & lifters again so why not replace all of them.


But before doing that I would take a stethoscope to see if I could pin point where that tick is coming from. Maybe it is a exh leak on the under side of the manifold.
Dave ----

 

Guys, I'm sorry I missed some information when I originally posted last night, I was pretty tired. New info in RED.

I don't have a stethoscope, but tried the screwdriver to the ear trick and it's really hard to pinpoint where sounds are coming from as I think it's resonating through the block and heads. Does a stethoscope work a lot better for that?

As info was changed in my original post, I got one new Comp lifter and put it in the spot where the valve got hung up and no change was detected.

Gonna call around for a stethoscope and go from there.

 

That is what I would do and go from there as I went back to read the red to see what changed and it looks like you have it all covered.


Maybe it is a bad flex plate?
Could just keep driving it till something breaks
Dave ----

 

Yes, a good stethoscope will have at least two modes, one of which doesn't have to be touching anything, just picking up the bad, bad, bad vibrations.

Have you thought about the cam walking?

 

When it first started and got the timing good and heard the initial loud tick (which was the rocker touching the valve cover) I said if she's gonna go, she's gonna go right now.

Just picked up a stethoscope and a length of aluminum flexible dryer hose for the exhaust to run outside. It gets rather ripe with a truck running in the shop.

I must say though, with the power this new engine has, this truck is gonna be a BLAST to drive. Can't wait to get this noise sorted out.

 

That never crossed my mind. Hmmm.

When I installed it, it felt good in the bearings, and when the timing gear went on, it hardly had any play front to back (maybe a few thou).....going off memory which is hit and miss right now.

 

Did some checking and the noise is there right from cold. Not as loud as when warmed up, but still there.

When warmed up, cylinders 1-4 are quiet, no noises at all.
Cylinders 5 and 6, the noise seems to be the loudest. 7 and 8, noise tapers off. This is checking right on the top of the valve covers. Checking through the intake or exhaust manifold, the noise carries and it's hard to tell where it's coming from. Pulled the valve cover and noticed nothing out of the ordinary. Also checked the inside of the valve cover for any rocker arm marks and found nothing.

I did check around the timing cover and by the fuel pump and heard no out of the ordinary noises. I was actually surprised to hear just how good the pump arm follows the eccentric on the cam gear.

I have a bad feeling I got a bad cam or lifter right out of the box. I really don't want to pull this thing apart, but I think it's inevitable.

This is the same noise I heard when these parts were in the old engine and it made that tick right from the start. Before, during, and after break-in.

Next step may be calling Comp and see what they say.

 

Yes, I think it is time to ask Comp for help. But before pulling it down I think I'd do what you mentioned - measure the lift with a dial indicator. But, watch for any sudden movements of the dial when slowly turning the engine.

 

I was thinking of doing this on the valve side of the rocker, but I think I may get poor results if a lifter bleeds down a bit. Do you think I'd get more accurate results if I put the indicator right in the tip of the pushrod? Then, there's no other factors involved. I can also make up a small centering thingy to keep the pushrod straight in the head and from moving side to side.

This sounds like a good evening job during the week.

 

It is really, REALLY tough to get straight on so there's no angle, and ANY angle changes the results. A jig/centering thingy would help.

 

Not knowing the push rod or push rod hole in the head maybe a nylon bushing that will fit not to loose around the push rod and snug in the push rod hole in head - like a guide, to hold the push rod from flopping around.


If it would not fit over the end of push rod it could be made like a valve keeper in 2 halves pushed into the head hole.
Still think I would remove the rocker so the spring will not push on the lifter.
Could also remove the rockers to give a good look over at this time.


Could the "tic" be piston slap or piston pin play? You say you hear it more when warm so gaps get wider when warm.
Dave ----

 

Definitely a valve train noise. Piston to cylinder wall and pin fit was really nice.

Yep, when I do the dial indicator check, the rockers will be removed and the tip of the indicator will be gauged in the hole of the push rod. I think even a piece of rubber tubing around the push rod into the head will be enough to hold it straight.

With the lifter sitting on the "base" of the cam, I'll zero out the dial and slowly roll the cam over and watch the indicator for smoothness. At the tip of the lobe, I'll take a measurement. If there's any major differences ( more than a thou or two), I'll know where to start looking and have something to tell the Comp tech guys.

 

A problem I had was in getting the dial indicator to be at the same angle, preferably zero, to the push rod on each cylinder. There are very few places to put the body of the dial indicator, so you are very limited. Given that, if you can come up with a way to position it from the rocker arm's stud you might be able to make your measurements repetitive.