I was listening to a guy's engine he thinks has a loose valve seat(s) It's a flathead six Willys engine that he did a ring , bearing job and valve job on over the winter.After a few hundred miles the valves got noisey all of a sudden.He adjusted them ..but once the engine is fully warm after a 10 mile ride the valve clatter gets a lot louder.He said when the engine was apart and cleaned up you could see exhaust seat inserts.He claims the guides are not loose, the cam and lifters in good shape. I head it run and once fully warmed up it does get what I call a lot of valve noise. Doesn't sound like a loose piston or pin.When the engine idles it sounds normal.Rev it up slightly and the valve clatter get much louder.Not one valve but all ,maybe this is nothing? Obiviously the only way to really know is too pull it apart to check it ?
I had one drop out of a 4 cyl OT Japanese engine. Made it sound like a diesel. My buddie's flattie dropped one out and it was eaten up and spit out by the engine, leaving only scars and scrapes behind. It can cause significant damage, so I'd open 'er up and fix it pronto.
Oil pressure appears normal,25 at idle and 40 going down the road on a fully warm engine.It runs nice,no smoke.... I had a guide get loose on a Triumph cycle and it souded very clicky like a valve out of adjustment.He didn't mess with the guides on this flattie 6.My limited experience on these engines is flatheads have pretty quiet valves
I was thinking,wouldn't a loose valve seat make more noise on a cold engine when heat hasn't expanded the seat faster than the block?
A loose seat sometimes finds its way back into its socket to confuse you. No idea where Willys put the sparkplug...can you see anything through that hole? Generally there will be a bunch of arc shaped gouges pounded in around the guilty valve location. Also, you might be able to remove the side plate and watch valve action on running engine. There should be some sort of monkey motion where there's trouble, and if seat is out you should see one valve with 1/4" of clearance!
I believe it's a Continential engine.He checked the valve adjustment cold cause that's what the manual says to do.They were all very close to what he set them when the engine was put together.He seems to know how to do stuff so it's as he says.The compression on a warm engine is 115 on 5 cylinders,105 on the other one. I pulled the fan belt,noise is still there.But something else I heard was a wirring noise as the engine is reved up.This is only a hot engine noise.The fiber timing gear was replaced when he rebuilt the engine.It could be a slight gear mesh issue.This noise along with "normal" engine noises may sound like something worse than it is? I tried to take a sound video but it just sounds like general noise.
A loose valve seat should show up with a compression, or leakdown test. when running you can have a little leakage passed the valves and not really have a miss, but low speed cranking these things show up with a comp test. If the seats were in the block when he did the rebuild and were fine then they should be ok now. Unless he overheated the engine. The seats with high nickel (hard seats) shrink if they get hot, more so then the block. This can loosen the press fit, but otherwise they just don't come loose unless the were just installed without enough press. I did an overhaul on a 1949 4 cylinder Jeep engine and was unable to locate cam bearings for it. I drove the old bearings back in and it didn't work so well. It lost oil pressure when hot and rattled and knocked.... I ended up tearing it all down and machining my own bearings. That had low oil pressure though, and thats why I asked. Normally pistons are noisy cold, and bearings and upper end noises (on overhead valve engines) show up hot. I have an electric stethescope that really helps isolate noises, but you can try a pry bar or peice of wood. Just hold one end tight to the pan, side of the block, head, or whatever, and the other end to your ear.
Stange stuff happens.Last night he drives over with a big smile.He took a long ride and the engine got quieter! The excessive valve clatter is gone and so is most of what I thought was timing gear noise.Maybe a few parts needed to "adjust" themselves,maybe the noise will return.But for now it sounds much better.
FWIW. Had one loosen up on a rider mower with a Briggs. Clatterted like hell. Staked it back in with a hammer and small cold chisel, finished the summer of '68 running fine, lost track of it after that. Ed
Normally only exhaust seats will have an insert. (Nickel chrome alloy or old school cast iron) Sometimes not unusual to come out if the engine is very high mileage or has suffered very extreme temps. If the insert is indeed moving, the valve will not seat and thus will have a miss like a burnt valve. It won't right itself either. So if the noise has disappeared it would be something else. A
I just read the posts again.. You say its a 6 cyl Continential engine. 227 or 245? Most didn't have inserts from new but they were soft around the seats and had inserts fitted when valves burnt out. A
I think Jeep(Willys) calls it a 226.There was a crack between two exhaust valves ,an old stitch repair job.The exhaust inserts were probably done at the same time. The noise is still gone..if it comes back I'll try to get a sound bye and post it.
Yep. I forgot about the 226. All those engines ended up in hyster forklifts until the late 80's. I still remember seeing a new one land on my doorstep. They did crack a lot between the seats. Comon repair practice was to stitch and insert. A
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