Failed valve retainers and bent valve

[Squizzbiscuit]

Hello all, first post to the site. I've been very impressed with the knowledge and willingness to share. I finely bought my first MV and could use some advice.

I bought a 65 M35a2, with a Hercules LDT-465 (I think). Previous owner had it for almost 20yrs. Last year, he fired it up and it over-revved. He dumped the clutch in 5th to kill it and let it sit till I bought it. Problem was a gummed up hydraulic head and I was able to get it cleaned up. It ran rough upon restarting and I had hoped it was just crap fuel/sticky injector. I took it for a short drive to see if it would clear up (hindsight, not my best decision). My trip ended with an audible rattle. I pushed in the clutch and there she died.

I pulled the valve covers and i found most of the valve retainer clips pushed almost all the way thru the top spring retainers. The rattle (i assume) came from the one retainer that completely failed and was spit out from under the rocker. The failing retainers I figure were hammered by the over-rev. Anyone ever see this?

So now I have one bent push rod, a bent valve (locked tight in the head), damaged rocker (does not move freely on the shaft), and a whole bunch more retainers with their clips punched almost thru, just waiting to wreck some stuff.

My next move is to pull the head to check piston condition. But I'd like to hear your opinions on my options.

- if piston is OK, I swap the head, replace failed retainers and clips. Say some encouraging words to the rotating assembly and run it. If piston is hammered, skip to option two.

- cut my losses and put my money into a replacement engine. (Eventually rebuilding the existing engine for backup.)

Thanks in advance, I have photos if it helps.

 

[cbrTodd]

Hello all, first post to the site. I've been very impressed with the knowledge and willingness to share. I finely bought my first MV and could use some advice.

I bought a 65 M35a2, with a Hercules LDT-465 (I think). Previous owner had it for almost 20yrs. Last year, he fired it up and it over-revved. He dumped the clutch in 5th to kill it and let it sit till I bought it. Problem was a gummed up hydraulic head and I was able to get it cleaned up. It ran rough upon restarting and I had hoped it was just crap fuel/sticky injector. I took it for a short drive to see if it would clear up (hindsight, not my best decision). My trip ended with an audible rattle. I pushed in the clutch and there she died.

I pulled the valve covers and i found most of the valve retainer clips pushed almost all the way thru the top spring retainers. The rattle (i assume) came from the one retainer that completely failed and was spit out from under the rocker. The failing retainers I figure were hammered by the over-rev. Anyone ever see this?

So now I have one bent push rod, a bent valve (locked tight in the head), damaged rocker (does not move freely on the shaft), and a whole bunch more retainers with their clips punched almost thru, just waiting to wreck some stuff.

My next move is to pull the head to check piston condition. But I'd like to hear your opinions on my options.

- if piston is OK, I swap the head, replace failed retainers and clips. Say some encouraging words to the rotating assembly and run it. If piston is hammered, skip to option two.

- cut my losses and put my money into a replacement engine. (Eventually rebuilding the existing engine for backup.)

Thanks in advance, I have photos if it helps.

Any valve that has touched a piston will likely fail eventually. If they get the slightest bend, each time they open and close it puts them through a loading cycle and they fail in fatigue where the stem blends into the head.

I would recommend replacing all the valve collets and retainers (plus any valves that have touched a piston as mentioned above) and verifying that none of the valves are excessively tight or loose in the guides. If there is no significant piston damage, roll all the pushrods on a piece of glass to make sure they are straight and reassemble and give it a shot.

 

[ToddJK]

CBR is right. Definitely gonna be some work to be done to get it correct. Hopefully you can find all the parts or a donor engine. I wonder if the bearings on the crank are good, would suck to do all that work to have a bad bearing show up next.

 

[rustystud]

Yeah I've seen this happen a few times. The problem is there is so much that can be damaged by an over-rev'ed engine. Like "ToddJK" mentioned you can have damage to the crank bearings, but more importantly your piston rods can be bent. Seen one engine that bent all six rods just "slightly" . Didn't find this out until the engine was going back together. By that time with new bearings, new rods, new pistons and rings, new valves and springs and retainers, rebuilt heads with new valve inserts you could have bought a couple of good donor engines and still have money left over for a good steak dinner and a trip to Disney Land !
Any engine that has had a "over-rev" failure is a suspect engine for the rest of it's life. Until you totally rebuild it you will never know.

 

[Squizzbiscuit]

I'm sensing a strong tone of engine replacement. I enjoy wrenching on things, but repeated engine failures will take the fun out of that in a hurry. Thanks again guys, your input is appreciated.

..... Anyone got a motor near Buffalo NY? Lol

 

[patracy]

Given the time/cost to rebuild. I'd also recommend simply replacing it. If they were a more "valued" engine like a cummins, cat, exc. Then certainly rebuild.

 

[davidb56]

I'm sensing a strong tone of engine replacement. I enjoy wrenching on things, but repeated engine failures will take the fun out of that in a hurry. Thanks again guys, your input is appreciated.

..... Anyone got a motor near Buffalo NY? Lol

Boyce Equipment in Utah has them and is a top notch company to deal with.

 

[ToddJK]

Could try Eastern Surplus, they are not too far. Have no idea if they have them available and if so, how much.

 

[MarkM]

You can pull the head but as many of us here think it won't be pretty. I would pull the head for the hell if it but start searching for a replacement engine. It happens.

Mark

 

[rustystud]

Given the time/cost to rebuild. I'd also recommend simply replacing it. If they were a more "valued" engine like a cummins, cat, exc. Then certainly rebuild.

Totally agree.