I'm experiencing what I believe to be some clatter in my valve train & am trying to find the root cause. My engine is a 400 out of an 80 F350. It was rebuilt by a local machine shop using TMeyer pistons & a Melling hydraulic flat tappet cam. Here are the numbers on the cam:

Most of the rockers, valves & springs were re-used; I got a bag with a couple old valves back when I picked up the motor, so I'm assuming they replaced anything that was out of spec. Motor starts fine & runs good at idle & low RPM's, but starts to clatter when it's revved up. MUCH more noticable when engine is up to operating temp - almost sounds like a 6.9 diesel. I followed the proper break-in procedures using Rotella 15/40 (because of its high zinc content) with ZDDP additive. All subsequent oil changes have been Penzoil 10/40 with ZDDP additive, so I really don't think I wiped a cam lobe. I haven't read about any "adjustments" needed on the valve train, and I don't think my cam would require heavier valve springs. I will try to get a video of it later & post up, but in the meantime, are there any obvious things I can check before running it again? I wish I had gone with a roller cam on my rebuild, but funds just didn't allow it at the time.

 

Check lifter preload.

 

Most stock Ford valve springs will coil bind at around .500 lift, at .512 exhaust lift your pushing the limits on those stock springs

 

Thanks! Anyone know of a good write-up on checking lifter preload on these engines? I'm not an engine builder, but am a pretty decent mechanic; just never messed with the valvetrain before. Would it be a good idea to replace rockers & springs while I'm working on it? Can this be done fairly easily without pulling the heads? I've got a fair amount of room under the hood on this 60.

 

What is your oil pressure ? is your oil filter clean of any metal particles ?

You can replace your springs and rockers in the vehicle and I'm sure there are good articles on how to do it. but first make sure your cam is on it's way out or it's all for nothing.

For starters bring a piston to TDC on compression and see how much preload you have if any and look for bent push rods.

 

Good point on the oil filter I would definitely start there first. Use a oil filter cutter if you can, they work great.
Brian

 

If it's so bad it sounds like a diesel, pull the valve covers and start wiggling the rockers to see what's loose.

Then pull and inspect carefully each component.

 

Had the same issue on the 400 I rebuilt myself a few years back...(1996) I reused the stock valve springs and used a Comp Cam 268 bumpstick. Had several pushrods that were loose and clattered so I installed the Crane rocker arm conversion kit with BBC roller tip rockers. I learned later that the ratio on the BBC rockers was a little less than a Ford set but it did the job at the time as my budget was fairly tight. I'm retrospect I wish I would have bucked up the extra money and used the right ratio. At the time I sold the truck I estimated that I had roughly 60k miles on the engine. I was also using Shell Rotella for the added zinc and that further reduced the amount of valvetrain noise that I was hearing. Also gave the oil pressure a nice boost.

 

Oil pressure is 60+ cold and runs at 40-60 when warm depending on rpm. Cut open filter after first oil change & it was clean. My weekend project is to hopefully open up the valve covers & inspect everything.

 

I've seen stock springs on these engines be completely incapable of controlling the valvetrain. I've seen them were you can push down on the retainer by hand and take the spring all the way to coil bind. Hydraulic valvetrain can be weird in that it can be noisy with spring loads that are too high(too much lifter bleed) or too low(poor valvetrain control). I think that you should just take a few springs off and test them using an accurate tester. That cam will probably work fine with 80lbs seat and 220lbs of open load but used up stock springs can be way below those loads.

I've seen a stock 400 Ford that would run fine at idle but if you revved the engine to more than about 3000rpm it would misfire, changing the springs cured the problem.

 

This may be totally off the wall.I put in a cam (don't have the specs handy) It was just a small one like what people call a r v cam. My top end was making noise and found out the rockers were hitting the top of the valve covers. Hope your engine is as easy as mine was. Happy New Year to all.

 

I've seen a rocker rubbing on the valve cover splash gaurd at the fill/vent holes. Aftermarket cover.

 

1977 351M. Cam numbers look a lot, near exactly even ... like the old Crane Fireball cam's specs that I installed in mine in the late '80s not too awefully long after buying the truck at 35,xxx, I used new stock lifters, original push rods, rockers and springs too. I know I have 60,xxx on the cam anyway.

Was on the road trip to Ga in '92, it was lifter clatter what caused me to start watching oil pressure closer. I had the stock electric gauge then. After we got home the next week, three sending units later, I found it had 4psi on a mechanical test gauge ... truck had 75,xxx then. My rod and main bearings were wore into copper, I swaped in new inserts and oil pump while laying on cold earth. I nstalled a plumbed in with tee mechanical gauge too. Today, still runs 60 psi cold and 50-60 psi warmed up on the highway. It'll idle hot at 40.

I know too that when I see oil pressure start getting a little low, time for a new oil filter (even if I don't change the oil too). She's never had other strange ticks, etc, except for that one time I jumped into passing gear on 411 there near Chatsworth, Ga. passing a tanker in Nov.1992 ... We was going to see Richard run his last race, see Alan win the Championship, see Bill win the race, and to haul a Shop Smith and accessories back home..

Oil in thnese engines goes from oil pan sump to oil pump to oil filter before it goes anywhere else.
Truck has 106,xxx now.

 

So I was able to pull a valve cover & inspect everything. All the pushrods seemed good - I could spin them when the valve was completely closed, but no movement in them at all. The rockers were another story. Most have a good 1/8" of lateral movement. Here's a video:


That seems excessive to me. Is it time to replace the rockers & pedestals?

 

It looks to me like there isn't any preload in the valvetrain for some reason. There should be enough that you can't easily spin the pushrods even after the engine has been off for a while. You might try grinding a little bit off of the bottom of a pedestal to give it a little more preload to see if the problem gets better.