Technical 'Welded' intake valve?!!!

OK, this is really weird. I put rebuilt heads on my hemi. Had the heads reconditioned by a local head shop (no jokes!) using Hot Heads guides and stainless valves. I have never used stainless valves before but am painfully aware of what stainless bolts do when installed without anti-seize.

I started my engine and tuned it but it was running really rough. I have run it at most 10 minutes. Finally decided to tear it down and install adjustable push rods since I used my old fixed length rods on the rebuild. Thought that might be the cause of my rough idle. When I got the valve cover off all the pushrods seemed perfect except cylinder #7. The intake rocker has 1/4" play! I pulled the rocker shafts off and the intake push rod was bent so badly it wouldn't come out. All the other pushrods were perfect. When I pulled the head that valve was open 3/16" and stuck tight. no piston interference thankfully. I had to tap the valve out of the guide with a drift and found the shaft was straight but the valve stem had 4 little 'warts'. Tried to show them in the photos below but hard to take clear closeups with my phone. There is one large one (3/32" diameter) and three smaller ones (1/32") space on the other side. They actually look like tiny wire feed spot welds and are super hard. I tried filing the big one and didn't faze it. It sure appears the stainless stem welded itself to the inside of the guide. Like I said, valve isn't bent, all other valves move freely. Will anti-seize the stem when going back together.

 

Looks like a lightning strike or maybe a static discharge

 

Looks like the guide was not honed up to size

 

That’s brilliant! I have heard of welding on a chassis with the engine grounded to it causing stuff like this. I used to work for a guy that ran Top Fuel cars and he said any time they welded on the chassis they pulled the motor or it could put pits in the bearings.

 

I'm no metallurgist but it sure looks like galling to me, lack of lubrication or the valve guide was not machined properly.

 

Guides were dirty when the valves were installed and the guide debris friction welded itself to the valve stem under the intense pressure caused by no or inadequate stem to guide clearance once the debris wedged in there. This typically shows up on fresh builds or at low mileage.

FYI, many, if not all valves are manufactured by friction welding a stem to the valve head, or a welding a hardened wear cap to the stem.

Eaton valves used to corrode at the weld in the days of high sulfur fuels. The weld was close to the head, below the guide. and was exposed to sulfuric acid. Once the weld corroded, the head would pop off and end up on top of the piston, summarily destroying the engine.

TRW valves didn’t have that issue because the weld was higher on the stem, and didn’t extend past the guide in operation.

 

Didn't do any welding on car, it's 28 years old on this build! I don't think they were gaulded. The stem is slick all around the beads which are raised. Dirt in the guide probably makes more sense. Anyway will super clean the guide and dab on anti seize. Wish me luck!

 

Probably were put together dry,,,,,,and / or the guide was on the tight side and dirty .
We just got some heads back,,,,,,the stems looked dirty like crap .
Felt gritty in the guides,,,,,,I cleaned them all very well .
Smooth as silk after that.

Tommy

 

My vote is inadequate stem-to-guide clearance. After guide installation they should always be honed to size before assembly.
I use a Sunnen Stem Hone:

 

I'd have to say lack of lube on startup would be my number 1 guess, then honing second.

Did these heads set for quite awhile before starting the engine?

.

 

No. Picked them up from the head shop and installed them withing a couple days, started it then. Again, 15 perfect valves, one screwy one. Shop who did the work does nothing but heads so have to assume they know their task?

 

You know what they say about "assuming" things! Sometimes these shops have a "new guy" there, who is a bit on the messy side, and by luck his work is OK, until someone actually figures out what the problem is, usually after throwing countless new parts in there.

 

You have a picture of the entire valve? Are there valve seals on the exhaust side? What does the ID of the guide look like?

 

Anti seize for something static I can see. Not sure if I would use it as assembly lube.
I would rather use oil if its not sitting for too long.

 

I'd be dropping the head of back at the shop and expect the damaged valve and guide to be replaced, along with a new gasket set.

 

Trash in the guide when assembled. It can happen to the best of shops. It only takes a speck or two of metal.

 

"Back when I was doing cyl heads, I remember this one time old lady called with an emergency while I was doing guides. The emergency was she ran out of skin lotion and needed the car to go get some. Dammit I was pissed, I had to get this thing done and..."

How often does shit like that happen? I'd bet more than we know.

 

When I saw this I figured we would be talking about an exhaust valve with the guide installed wrong

 

I always thought of anti-seize being kind of abrasive.

 

If that's your plan...you need a lot more than just luck.

This is the only way this should be handled. if you don't, chances are high you will be doing it again later.

Anything else is just shade tree and half azz'd....valve and guide are both junk now.

 

Without a doubt. Hopefully they'll make it right for him.

 

Thanx for the helpful insightful comment!!

 

I'd go with foreign material that didn't belong there. Reason, pick a number but that the guy doing the work got distracted is as good as any.
An issue with regular automotive machine shops is that few have a "clean" assembly area and all the work is done on the same workbench. Most just don't have money or space to have a separate clean assembly area or room .

I never assembled a head dry though I either dipped the tips of the valves in a a cup of motor oil or used a squirt can to oil the guides when I was ready to assemble it and then installed the valves and then put the springs on.

I'm with the others, I'd take it back and show them the problem.

 

Lightly sand the valves length ways with like 600 W/D. Some valves are just not that smooth after grinding and plating. I would use CMD extreme pressure lube on assembling.

 

Welding on a car or truck will not hurt the vehicle! I out fitted new beds on new trucks for years with no problems. I have many friends that are welders and have the welder actually mounted in a truck and weld everyday on the rig sometimes 12 hours a day six days a week!
If welding on a vehicle would damage a vehicle , surely, we would have encountered it in the forty plus years we have been doing it! We have never encountered a problem! Just my opinion!






Bones

 

Yep. I was just answering the guy's concern. If welding on a car did damage, I wouldn't have a hot rod!!!!!

 

Electronics are in general sensitive, and especially if the welding is done in a unsuitable way they may be damaged. If you put the ground clamp on the welded part near the weld, and keep the welding cables (and the current passing through other metal) away from wiring harnesses you'll probably be fine. On the other hand, get the ground cable tangled up in the harness and the magnetic field around it may induce voltages in the harness (think of it as a inefficient transformer; current makes magnetism, magnetism makes electricity in other wires in the magnetic field) , and if something sensitive is connected to that harness it may get BBQed.

Damages may not be obvious right away. Some electronic components can break down far later. My uncle had his 1980s Volvo rust repaired, drove it home, parked it, started it and backed out the next day and it dies just outside the parking spot. No spark. Electronic ignition module dead. Could be a coincidence, more likely damaged during welding - it was over ten years old and it picked a h*ll of a time to spontaneously die if there were no outside causes.


As for damage to mechanical engine parts and such? No chance, unless you intentionally run the current through them.

 

Hmm.



I checked my library. I quickly came to the conclusion, I'm lazy. Read all day and it'd still be a guess, I wasn't going to find the answer in a book.








I choose to answer it with traditional methods and assign a blame to it rather then a cause.
One of three things universal to the world and it's many mysteries. Like Dylan and Bud light.



It's God, man, or its magic that caused it, one of those will fix it, as well explain it away. Shout out to the internet for making it possible.

 

Putting anti-sieze on the stem will be basically useless unless your top end is not oiling. Anti-sieze is for bolts and spark plugs.
What happened with your valve is improper valve to guide clearance. If it were an iron valve you would have had the same problem. It got hot and galled. This is not an indication that the shop was a bad shop unless this is a common problem with them. Anyone is bound to miss one once in a while.

I have run stainless valves for years in one of everything and never had an issue. I normally also run bronze guides.

 

Actually,,the damage from welding can happen from grounding on one side and actually welding on the other .

This was discovered by Caterpillar many years ago .
After several bearing failures from newer engines,,,,,the bearing analysis showed many cross marks on the bearings ,,,(they had sort of lightning bolts across them ) .
Most welders in the field had extremely long hot leads,,,,,but usually had a ground lead that was half as long .
Anyway,,,,to reach the other side they would ground as best they could,,,,,then cross to the side that needed attention .
These engines are mounted very solid and are well grounded .
The power would arc across the bearings in many cases,,,,,,,the shortest distance to ground .
I’m certain that many were damaged at the Cat shops too,,,,,,,that’s probably why it got their attention,,,,,,warranty work ,,,,on their time .

I remember reading this bulletin many years ago when I was a kid .
They had pictures too,,,,,so it had to have happened,,,,,lol .

Tommy