I need help solving a problem with the 390 I just put in my 75 highboy recently. The engine runs very well but once warm the valve train gets very noisy. I think the noise is coming from the lifters. The engine is quiet when cold but starts getting noisy as it warms up. I hear the noise from multiple points. The engine has a high volume oil pump and decent oil pressure. I’m running 15-40 diesel oil with a quart of Lucas. One warm it makes the noise both at idle and when I give it gas. What could be causing it? I’ll try and post a video soon.

 

most likely either bad lifters or insufficient preload .

 

What do you mean by insufficient preload?

 

Here are some videos of it running and the noise.

 

You should have a lot more oil up there than that. what is your oil pressure?

How long have you run this engine and how long has it been this noisy ? do you know anything about it ?

FE's oil around one of the rocker shaft bolts. that bolt is undersized to allow oil flow. I'm wondering if someone didn't know that when they installed the rocker. or you have no oil pressure.

 

One completely warmed up it has 10-15psi at a hot idle. The first video show oil pressure 3/4 of the way warmed up. Everything up there had oil on it and when I reved the engine it would sling oil off the rocker arms out of the pushrod oiling holes.

I don’t have 100 miles on the engine yet. When I bought it the guy said it needed head work because it smoked on start up but he had never ran it since he bought it. I put mostly all new gaskets in the engine one I got it running. I don’t remember the lifter noise before I took it apart but it had no exhaust or headers on it so I might not have heard it. Pretty much everything I know about this engine is listed on this thread https://www.ford-trucks.com/forums/s...8&goto=newpost

I had it apart but was not aware of the bolt difference at the time although that’s the main reason I pulled the valve cover today was to check and make sure I had the necked down bolt in the right spot (I did). I would like to see more oil pressure but I think it is acceptable. I’m not sure if oil pressure is causing the noise though because in the first video you can still hear the noise with 50psi of oil pressure.

While all the lifters appeared not to be collapsed I could put a wrench on the rocker arm and collapse them in 10-15 seconds and create what seemed to be a huge (acceptable?) valve clearance. Another thing I noticed today while running it with the valve cover off was that if I pushed down on the pushrod side of the rocker arm with my fingers while running I could partially collapse the lifer and the rocker would start to get noisy.

Valve clearance with the lifter collapsed

 

It doesn't look like nearly the normal amount of oil to me, but maybe the video isn't showing it. often the oil will flow over the edge of the head, yours isn't even good and wet from what I can see. 10-15 lbs is pretty low.

To check your preload bring a piston to TCD on the compression stroke. you should have a preload on the lifter, it's pretty hard to measure without loosening off the rocker shaft but the lifter should be compressed a little .

Lifters will compress when the oil is off. you shouldn't be able to compress the lifter while it's running that's a problem.

 

I’m working on the truck again tonight. Here is what I’ve found so far. I double checked that the rocker rocker shaft bolts were all in the right place and I double checked that the rocker shafts are clear of sludge. Both of those were fine. But I did find a few possible problems. The pushrod tubes apear to be mushroomed out where the ends are pressed in and some of the ends themselves seem worn almost pointed like an egg. The rockers also seem to have quite a bit of wear on the tips and a little bit of play on the shaft.
I pulled one of the lifters to check it out and it seems fine but the internal plunger has a bit of side to side play(normal?). While running the engine with the valve covers off I noticed the noise seems to be coming from down by the lifters themselves. I’m stumped as to where the noise is coming from and what is causing it.


The wear on the rocker tips

“Egg shaped” pushrod end vs a round one

Most of the tubes apear mushroomed or flares where the ends are pressed in. Is this normal?

 

This is the engine you thought might be pieced together? My shot in the dark... have you measured the pushrods to see if they are the correct length?

 

Some wear for sure, probably made worse by oil starvation.

there really is no proper push rod length predetermined for any used or rebuilt engine. you have to measure for proper preload and check the geometry . wear, decking, head shaving , stem height ,cam base all make a difference.

If you don't want to spend the money for adjustable rockers a set of custom pushrods is the next option. but honestly until you get your oil pressure up and replace your worn valve train parts that would pretty much be throwing money away.

 

Yes it is. No I have not measured them. I don’t have a pair of calipers big enough

 

What I don’t understand is that the oil pressure isn’t that terrible. 10-15psi at a hot, slow idle. Now when it’s cold it slow idles at around 50psi. When it’s hot and I idle it up it’ll hit 50 pretty easy but I still don’t see much more oil st the rockers. If cranked over with the rocker shaft removed plenty of oil is shot out of the oil port in the head

 

You could get a pushrod checking kit like this one...
Competition Cams 7705 Hi-Tech Pushrod Checking Kit
Measure the length the pushrods should be with it and compare adjustable pushrod to your own.

 

That is about the only way to measure preload.

I'm not sure what to tell you on your oiling. I can tell you I get more oil to the rocker shaft with my drill priming an engine than you're getting running. maybe I'm just not seeing it in your video I can't say for sure. but I am sure your rockers and pushrods are whipped, which could be from insufficient oiling .or simply a lot of miles.

I have heard of clogged rocker shafts but I find that hard to believe. are you sure your pressure gauge is accurate ?

 

There's a lot of good information about some of this in this thread (but this guy was getting no oil) https://www.ford-trucks.com/forums/8...e-rockers.html