Bent/Broken Push rods

[marine6212]

I finally tore in to the engine the other day and found 4 bent push rods and 1 broken one. .... The engine was running and now this. The rods look like they have been that way for a while. Now I know why the 390 didn't have any power!!!!! Any suggestions ???????


Thanks,
Marine6212

[willowbilly3]

Over revving or sticking valves

[DuckRyder]

Is this engine stock?

Any work done recently...

[marine6212]

Is this engine stock?

Any work done recently...

Yes this engine is stock, It hadn't been started in 10 years +/- and I got it to start and run.. thought I had a pretty decen t engine. The Previous owner told me that there was a valve sticking. But would start working when warmd up. Didn't think much about it till I tore the valve covers off of it and noticed 5 of the rods were bent and one was missing. This truck has only been started and driven about 5 miles in the 2 months I have had it. I don't think that I did this I believe this has been this way for a while.

Semperfi,
Marine6212

[sideoilerfe]

I'd replace the valve train all push rods, (measure them as you remove them) and replace the cam and lifters. Start again with a new top end if you're sure the heads are good and you should be fine. If you're not sure about the heads, pull them. If they're good, then continue.

[willowbilly3]

The missing one is probably down in the valley. I'd still bet someone fired it up and revved the **** out of it. If you pull the rocker shafts you can tap on the valves with a hammer to see if any are sticky. There are addatives to loosen then up. I used to have a 312 that would stick valves and actually had a broke pushrod in the valley when I got it. I heard that using atf in the oil would help so I did. If I changed oil and didn't put atf in, valves would start sticking right away, even after 25,000 miles.
Just me personally but I wouldn't start putting a lot of new parts/labor into en old engine. If the heads or cam are shot then the rest probably isn't far behind.

[rubiranch]

I'd still bet someone fired it up and revved the **** out of it.

A very good friend of mine helped a friend of his restore a 1962 Galaxie 500 XL with a 401 hp 390. The guy who owned the car was constantly bending pushrods and Joe finally had a gut full and installed a rev-limiter so his friend wouldn't over-rev it any more, no more bent pushrods.

[mrtleavitt]

Also a good backfire will cause push rods to bend and break. Have any of those lately?

[BobbyFord]

An engine that has been sitting for years is prone to stiky, gummed-up valve guides. The valve stem hangs up in the guide and the cam tries to open it. Weakest link in the chain is the pushrod. Guarantee that's what it is, especially with an FE, seen it at least a dozen times. Brake cleaner on the guides after the springs have been removed (air up the cylinder to remove the springs and then remove the air to work the valve up and down in the guide) and a little trans fluid in the oil for 100 miles or so is the cure. (Don't let the valve fall) Some guys use a section of rope in the cylinder, with the piston at the top of the bore to eliminate the possibility of the valve falling into the cylinder.

[willowbilly3]

An engine that has been sitting for years is prone to stiky, gummed-up valve guides. The valve stem hangs up in the guide and the cam tries to open it. Weakest link in the chain is the pushrod. Guarantee that's what it is, especially with an FE, seen it at least a dozen times. Brake cleaner on the guides after the springs have been removed (air up the cylinder to remove the springs and then remove the air to work the valve up and down in the guide) and a little trans fluid in the oil for 100 miles or so is the cure. (Don't let the valve fall) Some guys use a section of rope in the cylinder, with the piston at the top of the bore to eliminate the possibility of the valve falling into the cylinder.

After you have the springs off you might try a good 1/2 drill and some B12 on those to get them un-gummed, just a thought, I never actually did it.

[rubiranch]

After you have the springs off

don't forget the new valve stem seals

[Rick]

What tool do you use to remove the valve springs with the heads on the engine? And where can I buy one?
Thanks

[Dragon]

Powerbuilt Tools Valve Spring Compressor
Part Number: 648690

http://www.partsamerica.com/ProductDeta ... yCode=3491

[rubiranch]

I would think most auto parts stores would have valve spring compressors.

I would also use a plastic hammer to smack the valve after you have put the spring, retainers, and keepers back together while you still have air pressure in the cylinder (and I like the rope idea too) to make sure that the keepers are seated. Just a couple good smacks to open the valve a bit and let the spring close it should work fine.