Ok, so I purchased a 72 highboy for my second oldest son, when i went to look at it, it ran very well. started great, idled well, it's a fairly clean truck.
But then I brought it home...

After I got it home I drove it around the block, revved it up, (it's got a true dual exhaust, with glass packs, it sounds really good.) and shut it off. The next day I went to start it and it had trouble starting, and after priming the carb with a little gas it fired, but with a slight knock/tap sound.

I did a lot of research here on the forums, and took the right/passenger side valve cover off, and the push rod for the valve that is second from the front of the engine was bent. I pulled the rocker arm then the push rod and fished the lifter with a magnet.

The lifter was stuck solid, so I purchased a new one and a new push rod. I soaked the new lifter overnight in oil, purchased a hydraulic lifter removal tool from napa and reinstalled everything, I put new plugs in, autolite 45's with a .35 gap for points ignition. Fired up the truck and it ran well, drove it to the gas station filled it with ethanol free gas and drove it home. I never opened up the throttle even as tempting as it was... lol When I went to fire it up this morning, it fired then died, and after priming the carb again it fired and ran but the knock/tap sound is back, I haven't pulled the valve cover yet to be sure but I'm betting the same lifter/pushrod issue.

Here are the details everyone is asking for by now... When i purchased the truck the gentleman told me it was his grandfathers and he took it from a 351 to a 460 (Bored and stroked). I am calling bull****, just by the research i have done here... in my research, I believe it is a 360... 5 bolts on the valve cover and the vin indicates the same. So it is entirely possible "grandpa" could have had it stroked to a 427 or maybe a little larger but doubtful considering the stock intake, vacuum distributor, and stock exhaust manifolds.

My plan for the day is to pull the valve cover and find the bent push rod, pull the corresponding lifter and replace both (with the spare parts I bought originally). It may be important to note I never changed the oil before driving the truck. (I know, dumb decision... I was just to anxious to check it out) but I'm changing it today with rotella 10-30 diesel service oil (for the detergents) and some marvel mystery oil, or lucas oil stabilizer whichever I get the most feed back for.

Are there any known Issues that could be causing my troubles? or is my plan for the day a good start to solving the problem?

I am really trying to not have to pull down the entire engine (as I'm sure you can tell by now) 1: I've never done it, 2: I travel for work and am short on time
I'm not saying I can't do it, I just don't want to if its avoidable.
I'm much more of a diesel guy but love these old highboys. So any useful info would be wonderful...
Thanks everyone!

 

Stale, varnished gasoline will do it.

 

No it won't. Not the lifters. Gasoline affects the valves.


I had the same problem a couple times. Lifter plunger will get stuck and bend a pushrod. I never figured out why, just chocked it up to cheap lifters. I put in a quality set and never had another issue with them.

If the valve spring pressure is higher than stock, or you have a bigger camshaft, you really need better pushrods. I've got stiffer springs and a higher lifting cam, I bent a stock pushrod once while I was driving down the highway. Don't know why, no reason really. I assume the pushrod got fatigued and Just couldn't handle it anymore. I replaced all of them with a heavy duty set and that took care of that...

 

Thank you 351Cleveland! So after a little research I found some comp cam lifters for it, which I will pick up, but the only performance pushrods I found (I didn't do a TON of research but a little) were 9.157's and I need some 9.56's... any suggestions?

 

Keep looking. They are out there. Did you try summit?

 

summit doesn't have any options, But after looking at jegs.com they show some performance pushrods from comp cams to match up to the lifter I'll get. thanks! But for inquiring minds the pushrods that are listed for the fe engine have oiling holes in them, the push rods i pulled from the truck are non oiling heads... dunno if that matters or not

 

Before you do the work, I recommend running a treatment of BG EPR. Run it for 45 minutes or so, and drain it hot. That'll get rid of anything that may be causing the lifters to stick, then run the 10w30 or 15w40 diesel oil.

 

I didn't say anything about lifters.

 

But the OP did. He said that a lifter is the cause.

 

Good advice. Flush out anything that may be in there.

 

Okay after running the motor flush through it and draining oil I disassembled the valve covers and it is not the same push rod... it is now on the number 7 cylinder I believe still on the passenger side all of the lifters seem to be pumped up fully and have zero give in the spring... Is this a sludge in the oil issue and should I consider replacing all of the lifters?

 

Lifters become very firm when pressurized with oil. Let it sit for a couple hours so they can bleed down.

 

My 7.3 had two lifters lock solid at the top of travel, but it had valve spring travel left so it just held the valves open. One was an intake so it was very loud and smoked like crazy.

 

I am an inquiring mind and this isn't the first time I have heard that FE's are supposed to have pushrods with holes for oiling. I have a 428 FE and I too have solid PR's. Jeffafa or ND may be able to answer our question. I'm a little concerned to be honest, since I recall the 390 I had in my slick ( nicest body style of the F series IMHO ) had PR's with holes.

 

He says he has bent pushrods, like in the title. Bad fuel can do that on startup, no?