Briggs ELS 725 Exhaust Pushrod Issue

[HondaG100]

Almost sounds like the cam gear is in the wrong tooth causing your valves to hit the piston. Maybe messed with by someone else.

[KE4AVB]

Almost sounds like the cam gear is in the wrong tooth causing your valves to hit the piston. Maybe messed with by someone else.

Thanks for mentioning that as the engine has been a part. I haven't even thought of that one; of course, I not looking at the engine either. It is very good possibility. Even a partially sheared crank timing key could been thrown in there too as something to check.

[davbell25413]

The timing marks are matched/lined up. I checked the timing marks when the crankcase was off and no pushrods in the lifters. As of right now there's nothing on crankshaft as far as PTO clutch, pulley, etc. Its only in a bind on cylinder #2 on the exhaust pushrod. Turns over just fine without it being in there. I'll check the flywheel key.

What about stretched valve spring on the exhaust? The keepers were wedged in the retainer like they dropped further when the engine got too hot from running on no/low oil.

[Deere2me]

The timing marks are matched/lined up. I checked the timing marks when the crankcase was off and no pushrods in the lifters. As of right now there's nothing on crankshaft as far as PTO clutch, pulley, etc. Its only in a bind on cylinder #2 on the exhaust pushrod. Turns over just fine without it being in there. I'll check the flywheel key.

What about stretched valve spring on the exhaust? The keepers were wedged in the retainer like they dropped further when the engine got too hot from running on no/low oil.

For what? It ain't got nuthin' to do with the valves, period! If yer gonna waste time by checking keys, then check the crank gear key!

Then, when ya get done with that, bang the exh. valve guides back down where they belong, stake or otherwise secure em ( another long story), replace the exh. valve spring retainers/ collars, straighten the pushrods. and fire that mutha up!

[KE4AVB]

Dave, Finally got some free time here to look at your picture in a blown up size. If I seeing this correctly it looks like that valve guide is out place. That shiny area on the valve guide indicates to me that is out place. What do the rest of you guys think?

[davbell25413]

The other side looks just like that. Also thats how the Briggs manual shows the exhaust guide also unless the manual can miss leading.

[KE4AVB]

I was hoping someone here has had this problem before or had the time and a cylinder head on hand that they do some measurements on for you. I would say check the valve lift measurement but I have yet to find that measurement listed anywhere nor have I found how high that exhaust valve guide should be sitting.

Personally I have only had one cylinder head problem here in 5 years of working on these engines and it was a valve seat that came loose and was crushed by the piston.

[davbell25413]

I repulled the crankcase apart. Crankshaft gear is fine. I Think I found the problem with the mag journal on the camshaft is worn and has end play in the hole on the block. Manual says mag/pto journal reject is .623 and I have .500 on my digital caliper. Intake lobes are 1.225 and I have 1.235. Exhaust lobes are 1.223 and I have 1.225.

[Deere2me]

I repulled the crankcase apart. Crankshaft gear is fine. I Think I found the problem with the mag journal on the camshaft is worn and has end play in the hole on the block. Manual says mag/pto journal reject is .623 and I have .500 on my digital caliper. Intake lobes are 1.225 and I have 1.235. Exhaust lobes are 1.223 and I have 1.225.

If accurate, that amounts to, like, 1/8th (.125)! How did you not catch that the first go round?? Sheesh. I ain't never seen a cam or a cam bearing/bore worn that much.
To be clear, are you talkin about RADIAL play ( as in shake, bore too big) or AXIAL play, commonly called END PLAY, where ya can move the cam or crank lengthwise between the thrust FACES? BIG difference.

[davbell25413]

I mean it wobbles in the hole loosely from left to right and around in circle motion. It didnt wobble that bad when crank gear is in place but I removed the crank gear is was like, OMG.