Dropped a valve

[contagious]

Dropped a valve on my fresh built 540.The exh. valve on #2 cyl. broke about 3/4 of a inch down the stem.?Wtf.Ferrea 6000 series valves,4.5 bore with 4.250 stroke,rhs heads,lun cam 740 exh 758 int lift.Put a new radiator in the car and was in the shop checking the car fired it up and ran it for 8-10 minutes only got to 150,so got out of the car and started checking for leaks,bliped the gas by hand a couple of times to help put a little more heat in it,sounded funny so jumped back in the car to check oil psi it was 55,hit the gas one more time(dumb ass)to clear it up when it came back to idle,it locked up.!!

Never seen one break at the stem like that,zero passes on the motor,only shop time may be an hour and half of run time.one pass down the local road in front of the house,it saw 6000 rpm on that pass,but lots of run time after that.Roller cam and howards roller rockers crower roller lifters all brand new.pulled the heads and the others 7 cylinders are happy,No contacts marks on any other valves or the pistons.WTF??

[Tod74]

I know this isn't helpful and you are looking for a cause, but I will still say it anyway.

Dude...that f*&*ng sucks. :( Your luck is about as good as mine. Did it just break or did it break because it dropped and got smashed? How much damage to the block and head?

[contagious]

If it wasn't for bad luck,wouldn't have any luck.!!!!!,Don't think i can save the head(brand new) piston has several holes in it,(brand new) and yes it looks like the stem broke and then the valve dropped.never seen one break at the stem like that before.As i said before the other seven cylinders are happy,and look great.Beats me?The valve spring came off with the stem still in place with the keepers ,and retainer all in one piece.!!! go figure. :oops:

[Tod74]

I never lost one that new but I broke a lifter after 21 or 22 passes and lost the block and all..so I know how it feels.

[bbchevy]

1st Thing I would check?
Coil Bind on the Rest of the Valves?They DONT jsu Break,for NO Reason?
Who set the Heads Up?
I would'nt see why the Head cant be Saved?
I have had them come apart at 9000 in the Lights and,a little Dye Grinder Action,Some Alu.Tig work,a few New Seats and Valves.And back at it!
If it broke at a Idle,IT CANT BE TO BADDD!
Later
G 8)

[TS1955]

Dropped a valve on my fresh built 540.The exh. valve on #2 cyl. broke about 3/4 of a inch down the stem.?Wtf.Ferrea 6000 series valves,4.5 bore with 4.250 stroke,rhs heads,lun cam 740 exh 758 int lift.Put a new radiator in the car and was in the shop checking the car fired it up and ran it for 8-10 minutes only got to 150,so got out of the car and started checking for leaks,bliped the gas by hand a couple of times to help put a little more heat in it,sounded funny so jumped back in the car to check oil psi it was 55,hit the gas one more time(dumb ass)to clear it up when it came back to idle,it locked up.!!

Never seen one break at the stem like that,zero passes on the motor,only shop time may be an hour and half of run time.one pass down the local road in front of the house,it saw 6000 rpm on that pass,but lots of run time after that.Roller cam and howards roller rockers crower roller lifters all brand new.pulled the heads and the others 7 cylinders are happy,No contacts marks on any other valves or the pistons.WTF??

Did it break just below the lock groove?

TS1955

[contagious]

Did it break just below the lock groove?


Yes ,the peice of stem left in the keeper and retainer was about 3/4 inch long.

[gearhead1011]

It's possible the rocker geometry is off. If the roller was rolling too close too or off the edge of the valve the side load could have broke the stem in the area you're describing.

[contagious]

It's possible the rocker geometry is off. If the roller was rolling too close too or off the edge of the valve the side load could have broke the stem in the area you're describing.


I will check this very close when i put it back together.

[TS1955]

It's possible the rocker geometry is off. If the roller was rolling too close too or off the edge of the valve the side load could have broke the stem in the area you're describing.

I agree!

TS1955

[contagious]

Took my time putting this together.Used adjustable pushrods to get the right length to get the roller in the center of the tips.they move from the center,forward about an 1/8 back to center,used dye to check.They were a little off center on the exh,but not any where close to off the tip. You never know when its up and running i guess,something was WRONG. :roll:

[TheRabbit]

Something has to be wrong and looks like the guys are already giving some good tips. I just wanted to add that sucks and I hate to hear anybody breaking parts. If the heads are aluminum they can be fixed no matter how messed up they are.

[contagious]

Thanks,you are right something is not happy.!!!Built lots of engines,but i'm not a master engine builder,so posting problems and looking for ideas,thanks to all for advice,that's what i a'm looking for.Thanks again.!!!!!!

[Tod74]

YOU should set your pushrod length so that when you are at half lift the valve and the centerline of the rocker arm form a 90 degree angle. The roller tip won't likely be dead center when the lifter is on the base circle. On a BBC it will likely be toward the inside just a little,at least mine always are.Mine never start out centered up unless the pushrod is too long.




just my opinion I am far from an expert.

[zipper06]

Just a NOTE, Tracy Smith dropped a valve at our RJ friends meeting at Byhalia in Sept. He broke the int valve head off on #2 cylinder about 1/2" up from the head. Luckly it went up into the valve pocket and didn't do a lot of damage to the head just a couple valve seats and some welding in the pocket. It didn't even punch a hole thru the piston, but beat it up pretty good. They were also Ferrea valves. I built the 388 short blk. but didn't install the heads. He was too tight on the valve to piston clearance. 6 holes was barely tapping the piston with the intake. I personally would not recommend less than .060 on the int. and no less than .100 on the ex valves. He says he checked the ex and they were around .080. Rocker geomertry was good according to him. He had .017 steel shim gaskets on a 48 CC head with flattop pistons, it's now costing him about $600.00 to put it back together, with .050 MLS gaskets. The short blk is a dirt cheap build, i mean less than $1,000.00 with cast steel crank, SIR rods and Hypereutectic pistons. Still in a 2950 lb Camero it ran best of 6.29 @ 108 MPH, with 1.27 60 ft times. (cam is special and i won't talk about it)
I'm not saying this was your problem, but i am saying that there may be a problem with some Ferrea valves.

Just making a point.

Zip.

[TS1955]

My concern would be where it broke. I've seen valves break down around the head but never up around the top of the stem!

TS1955

[TheYellaBrick]

I forwarded this thread to my brother, an engine builder extrodinar, and here is what he said;

I'm gunna pass on this one (as far as posting), too many variables and the guys have already said the obvious. Sounds like a combination of improper valve train geometry and possibly piston contact - the exhaust valve is really strong down at the valve head but not so strong up the stem, may have hit the piston and loaded the stem up high to cause it to crack, then fail - the damage to the valve didn't happen at idle! Just happen to come unglued at idle.

[contagious]

There is no contact piston to valve,did the math and checked with clay,over 100 thous on the exh and more on the int.The other seven cylinders and valves are clean ,no contact marks on pistons or valves.The Rocker geomertry need's to be checked very well as i'm the one that set it up as well,there was a little off center movment if i remember,but nothing off the tip.needs checking again for sure.Thanks for the help.!!

[curtisreed]

The one answer that gives no satisfaction to the OP trying to find a cause is, sometimes things just break! Really sorry for your misfortune.

Curtis

[contagious]

sometimes things just break



It's all part of the game,if you have thin skin,this game is not for you.!!!!LOL!!!! :lol:

[Tod74]

There is no contact piston to valve,did the math and checked with clay,over 100 thous on the exh and more on the int.The other seven cylinders and valves are clean ,no contact marks on pistons or valves.The Rocker geomertry need's to be checked very well as i'm the one that set it up as well,there was a little off center movment if i remember,but nothing off the tip.needs checking again for sure.Thanks for the help.!!

Correct valve train geometry is the geometry that produces the least amount of sweep on the valve tip.

It doesn't matter if it is centered on the valve or not. Set the pushrod length so the valve and rocker centerline form a 90 deg angle at 50% lift and you will be really close.

In order to put the roller in the center on any of mine the pushrod had to be way too long. They are usually offset toward the inside.

[zipper06]

I'm telling on myself here, and it may bite me in the butt, but i built a 481" a couple weeks ago for a person in Ms. He brought me a set of BB2 Extra heads that the person who did the work on them used recessed retainers and super 7 locks. I dislike these retainers because it's necessary to use a longer push rod for the rocker to clear the retainer. I put it together and had trouble getting a good geomertry on the exh valve useing available push rods from Comp cams. The ent. came out good, but i'm still concerned about the exh geomertry, i had .120 int clearance and .190 exh. clearance with the pistons. The whole engine was a nitemare, it had a cross drilled chevy steel crank, the weakest that GM ever made, it had Speed Pro dome pistons, probably 800 grams and the block had 3 Helicoils in it. But WoW :shock: it had Lunati Promod rods, i just hope it lives. I know a person who spent tons of money on a 406" sm/blk (2 times) and neither lived more than a few passes. He then put togother a junk yard 406 and lasted 2 seasons and ran better than either one of the good motors :o go figure.

Zip.

[Tod74]

I got 20 sum passes out of my 1st BBC before roller lifter broke, cracked/dented the block in the cam tunnel,ruined the cam, beat up 2 of the rods around the cap where it smashed into lifter parts. So much crap went through it the crank had to be turned. :(

to make it worse the block was a december 69 cast 512 block(1970 ls-5)

[TheRabbit]

Sorry guys, I'm done reading this thread. With all the bad luck going around I don't even want to think about mine comming apart. If it does I'm just gonna sit on floor and cry :( :( .

[contagious]

While i have your attention,I used felpro mls heads gaskets on this build,first time using them.Can i reuse them,or should i get a new set.?

[zipper06]

I got 20 sum passes out of my 1st BBC before roller lifter broke, cracked/dented the block in the cam tunnel,ruined the cam, beat up 2 of the rods around the cap where it smashed into lifter parts. So much crap went through it the crank had to be turned. :(

to make it worse the block was a december 69 cast 512 block(1970 ls-5)

Todd, i'm almost betting you had horizonal lifter ties on that cam, i had that happen in the 80's with 7/16 push rods, it broke an end of the one of the ties. I'll never in my life time use horozinal tie lifters again.

Contagious, they say you can reuse the MLS gaskets, i've never ran them so i can't speak personally, but i do reuse Copper gaskets, as does every top fuel and top funny car owners do.

JMO

Zip.

[Tod74]

THEY were the verticle bar lifters from comp cams. Their cheaper ones."super roller lifters"

At that time I incorrectly thought that lash would get tighter when hot so I set the lash cold at .028 and .030 per the cam card. This was my first solid roller . My opinion is I probably had way too much lash when hot and beat the lifter to pieces. The link bar was broken and the lifter obviously turned sideways anf ground the cam up. The roller wheel was also in many pieces. don't know what broke first my guess is the roller. This was in 2002.

live and learn. :oops: