Lost a Motor last night.

I seriously doubt that, based on the OP's original post, that the valves hitting the pistons are the ONLY problem. Normally if you have P-V clearance issues, it will show itself within the first seconds of initial fire-up, and if it doesn't show then, it will show itself on the first burnout. Been there, done that. And even then, worst case scenario, valve heads would break off and you'd see all kinds of carnage, jammed into the heads, piston tops, etc. Normally, just lots of bent valves (all of 'em).

He said that it slowed significantly before it broke, like it was "locking". Usually that means a bearing spun or stacked, and if it's not caught and shut down quickly it can lead to broken cranks, rods, etc.

Now I don't know what kind of timing chain set is in that engine, but I've seen many a double roller chain BREAK when something lets go. Sometimes even something as "simple" as a rod breaking...can cause the crank to get jerked around pretty hard and bust the chain. If the chain breaks, inertia of the crank, converter, the car rolling forward and spinning everything....well if the cam stops and the pistons are moving, you'll have bent valves usually.

I have been through this stuff many times unfortunately. 99% of the time when I had bottom end failures of some sort, the valves get bent or broken. I like to use undercut stemmed valves because they will bend most of the time rather than break. At least that way I can salvage some pistons for maybe a future build. And possibly save the head(s) as well.

But from what I've read in this thread, lots of folks are saying that the valves have hit the pistons and caused the holes in the pan. I say that is just not very likely. Like I said, usually if the valve were hitting, they'll bend or break...usually bend....but that doesn't explain why there's dents in the oil pan

Either way we look at it, it is still very unfortunate.

Good eye Mavman.... You can see on #2 the witness marks that the piston was turning as the valve was contacting it.
Wonder what the botton end looks like.

Originally Posted by 351bolt

Ya I got the 4 cyl figured out. Bad head, burned valve, cracks. Just got the rebuilt yesterday, hopefully get it running this weekend.

Who built your cage? Custom or kit?

Pete

Ron Pircey is building the cage, he's located on hwy 99 just south of Federal Way. Art suggested I use him, he told me Ron was a talented guy and that he had worked for him for several years before going out on his own. WWW.RONPIRCEY.COM

I've had a couple 2.3 heads with cracks, other than that, the 2.3 is a stout
little motor.

Originally Posted by mavman

I seriously doubt that, based on the OP's original post, that the valves hitting the pistons are the ONLY problem. Normally if you have P-V clearance issues, it will show itself within the first seconds of initial fire-up, and if it doesn't show then, it will show itself on the first burnout. Been there, done that. And even then, worst case scenario, valve heads would break off and you'd see all kinds of carnage, jammed into the heads, piston tops, etc. Normally, just lots of bent valves (all of 'em).

He said that it slowed significantly before it broke, like it was "locking". Usually that means a bearing spun or stacked, and if it's not caught and shut down quickly it can lead to broken cranks, rods, etc.

Now I don't know what kind of timing chain set is in that engine, but I've seen many a double roller chain BREAK when something lets go. Sometimes even something as "simple" as a rod breaking...can cause the crank to get jerked around pretty hard and bust the chain. If the chain breaks, inertia of the crank, converter, the car rolling forward and spinning everything....well if the cam stops and the pistons are moving, you'll have bent valves usually.

I have been through this stuff many times unfortunately. 99% of the time when I had bottom end failures of some sort, the valves get bent or broken. I like to use undercut stemmed valves because they will bend most of the time rather than break. At least that way I can salvage some pistons for maybe a future build. And possibly save the head(s) as well.

But from what I've read in this thread, lots of folks are saying that the valves have hit the pistons and caused the holes in the pan. I say that is just not very likely. Like I said, usually if the valve were hitting, they'll bend or break...usually bend....but that doesn't explain why there's dents in the oil pan

Either way we look at it, it is still very unfortunate.

To clear some of this up, All eight "undercut stemmed" exhaust valves hit the pistons and were bent,#2 two rod is broke off just above the bolts, #2 and #6 piston and cylinders are damaged, the cam was hit and damaged as well. I'm not 100% sure, but amazingly the crank looks savable. The cloyes timing chain looks fine looking from the bottom up. I left the front cover on for our builder to remove himself, because I suspect that's where the problem started I will update as soon as I hear more from Dave.

Looks to me like that motor was seriously over revved beyond the capability of the valve train and rods. Maybe valve float was actually occuring instead of "hitting the 7000RPM rev limiter"? Just a thought.

what kind of rods were in it?

The rods were Probe 5140 steel. There was NO valve float. There was 270 plus pounds of seat pressure, it pulled insanely hard all the way, never laying over to lack of valve train, it was definatly the chip it was bounsing off.

It's apart at the machine shop now, it sheered the cam pin and spun the number two rod bearing, I don't know what order this happened in, but I imagine the spun bearing happened first.

The theroy is: we were loosing oil pressure at the end of our runs and didn't know it, we have a guage and no light on the oil pressure.

The machinest told me he had a guy grenede three big inch Windsor drag motors to lack of oil at the end of his runs, once he installed a accumulator
he has had no more problems.

What do you guys think?

Originally Posted by mavman

I seriously doubt that, based on the OP's original post, that the valves hitting the pistons are the ONLY problem. Normally if you have P-V clearance issues, it will show itself within the first seconds of initial fire-up, and if it doesn't show then, it will show itself on the first burnout. Been there, done that. And even then, worst case scenario, valve heads would break off and you'd see all kinds of carnage, jammed into the heads, piston tops, etc. Normally, just lots of bent valves (all of 'em).

He said that it slowed significantly before it broke, like it was "locking". Usually that means a bearing spun or stacked, and if it's not caught and shut down quickly it can lead to broken cranks, rods, etc.

Now I don't know what kind of timing chain set is in that engine, but I've seen many a double roller chain BREAK when something lets go. Sometimes even something as "simple" as a rod breaking...can cause the crank to get jerked around pretty hard and bust the chain. If the chain breaks, inertia of the crank, converter, the car rolling forward and spinning everything....well if the cam stops and the pistons are moving, you'll have bent valves usually.

I have been through this stuff many times unfortunately. 99% of the time when I had bottom end failures of some sort, the valves get bent or broken. I like to use undercut stemmed valves because they will bend most of the time rather than break. At least that way I can salvage some pistons for maybe a future build. And possibly save the head(s) as well.

But from what I've read in this thread, lots of folks are saying that the valves have hit the pistons and caused the holes in the pan. I say that is just not very likely. Like I said, usually if the valve were hitting, they'll bend or break...usually bend....but that doesn't explain why there's dents in the oil pan

Either way we look at it, it is still very unfortunate.

Mavman,
I think your accessment has been very close. Why did we loose the rod bearing though? Have you had oiling issues at the end of a run?

Anyone ever hear of "Power Punch". It suppose to be some good stuff. Sold in the Pacific Northwest.

www.powerpunch.biz

351W's NEED extra bearing clearance because of their huge 3" size. I would look for 0.003" and would be using 3/4 groove racing bearings. Unless you are using watery thin oil, I would look for between 0.0030" and 0.0035" on the mains. 0.0025" on the rods.

Install a high volume pump for insurance, and add a large BAFFLED oil pan that will provide a total capacity of around 8 quarts. Canton makes some nice units. Get one that is either DEEP and narrow, or has the 'roadrace' baffles. 'T' pans with wide bottoms and no baffles are NOT good when the oil gets sloshed around.

As for the accumulator... not a bad idea, but address the above first.

Good Luck!