Is My New 383 Gonna Be Toast!!???

[Moonunit 451]

OK, driving down the freeway at about 60mph all the sudden I get a hell of a noise coming from up front, at first I'm thinking (hoping) it's a header gasket goin', but NO! I'm dropping a cylinder, losing power. No cell phone (long story short, forgot to pay the bill).

So I drive it about a mile to the next exit and get it into a parking lot. It's definately in the Dr. side valvetrain. While I'm totally bumming out waiting for it to cool down I spy a guy on a cell phone nearby. So I bum his phone and call a vette owner who I am supposed to meet with and he decides to continue to where I am to get his wheel.

Next, an urgant messase to another local vette owner who happens to live nearby, no answer, but I know he'll get back to me, one more call to marshal the forces and I go to tearing into it.

I get the valve cover off and the #3 (? exhaust) rocker don't look quite kosher. I touch it and it flops over THE STUD IS BROKEN OFF and the rocker is just sittin' there still on the pushrod. There's aluminum filings everywhere from the valve cover

One buddy shows up, the push rod is not bent, the plug is not damaged. The wheel buyer shows up, my kid is sick, the other guy calls and shows up a short time later. After much discussion we go and buy some ARP studs and decide that it's getting driven home.

During the install and valve adjustment the local guy is convinced that my pushrods are too short, and the guideplates are not properly aligned. Of course, being a true idiot I failed to check the geometry when I replaced the Crane Golds with Promags about a month or so ago. I drove it home, about 35 mi. and did an oil change with Mobil1 and a K&N filter. I haven't had a chance to check the filter oil yet I'll do that tomorrow.

Of course I cleaned up the head of debris as thoroughy as possible prior to replacing the stud and rocker. I'm going to get the valve train professionally set up.

But bottom line, is the motor imanantly doomed?Here's links to some pics.

http://forus.com/moonunit/corvette/BrokenRockerStud194.JPG
http://forus.com/moonunit/corvette/BrokenRockerStud195.JPG
http://forus.com/moonunit/corvette/BrokenRockerStud198.JPG

 

[WhalePirot]

"is the motor imminently doomed"

I do not see why it would be, unless you also broke or bent a rod , bent a valve or punched a hole in the piston. One step at a time, here.

A compression check is just one of them.

Sorry, pal. I know the agony of 'clean-up' items on these hot motors; all too well.

 

[bradfordsvettes]

don't think you would have any bad things coming down the road . check the geometry there may be to much stress on the studs steve

 

[Ken]

... bottom line, is the motor imanently doomed?

I doubt it. The valve just wasn't opening is all, when the stud broke. At any rate, the engine wouldn't be hurt so bad that it couldn't be repaired. Keep us informed Colin.

Hell, you know what I've been through, right? How would you like to get your new engine so hot that the coolant was bubbling out of the reservoir like it was a geyser? I pegged the temperature gauge at 300°!! :eek

 

[WhalePirot]

Hell, Ken. Mine did that today and the gauge read 'Low temp'.

 

[jenavet]

moon
i did that last summer,but my pushrod punched a hole in the side of the lifter...i found all the pieces but 1 small piece.....i also bent the valve very slightly,so it misfired a bit....i pulled the head,replaced the valve,lifter and rocker...and i raced her 37 more passes and she threw a rod....and guess what i found welded to the rod journal...yep,that missing piece of lifter......so i guess as long as she runs good and you found all the major pieces,i wouldnt worry too much.....when i had the motor rebuilt,i had them screen all the oil returns in the valley so if it happened again,pieces wouldnt go down into the lower end.......1 thing i couldnt help but notice in the pic of the rocker stud...looks like the rocker stud is 7/16 but the base is 3/8[part that threads into the head] if you ever pull the head,you might want to have a machine shop put the 7/16<<<7/16 rocker stud...much stronger...its easy to see if you are in the ballpark of your geometry as well...what i do is watch the tip of your roller rocker and how it rides on the top of the valve stem from valve fully closed to valve full open[max lift].......when the valve is fully closed,the roller rocker tip should be on the push rod side of the valve stem[make sure no part of the tip or rocker body is on the keeper,retainer or spring.....bring the valve up to midway lift,and the tip of the roller rocker should be dead center of the valve stem......go all the way to max lift,and the rocker tip should be on the far side of the valve stem[exhast manifold side],but not hanging on the edge
of the valve stem or touching the keeper or retainer..........all this method does is gives you a quick method of seeing if you are way off or not.........i pull the valve covers off my race car after everyrace day now and check lash and valvetrain geometry.

 

[jenavet]

oh ps...i forgot to mention...you might want to go around and check your valve spring pressure as well......if you have a hurt or weak set of springs,it will create all kinds of valvetrain geometry funk as you are cruising down the road.

 

[-=Jeff=-]

I did the same thing 2 years ago to my #7 exhaust valve. Stud broke and all the pieces stayed until I pulled the cover.

I had 3/8" stud and went to 7/16" stud, The Head side was still the same but I it seems to be fine.

I also agree with jenavet on the way to check the pushrod length, btu I have also used a marker on the valve tip and then set it up and rotated it a few times and took it apart. the marker will wear off on the area touched buy the rocker.

 

[grapeknutz]

That stud looks like it was already cracked when you installed it! If it were me I would check the rest of those studs for cracks.

 

[Moonunit 451]

Thanks for the responses everyone. For some reason I've checked the forum over the last few days and didn't think anyone had responed :confused

Anyway, I talked to a couple people at Comp Cams yesterday. One guy told me that from the description of where the stud broke that my push rods were too long, not to short. It's gonna be next week before I can get the builder whose gonna do the geometry check to free up some time. Everyones trying to get to the track ya know.

jena, the 7/16's is the end that bolts into the head. In my infanite wisdom I didn't replace the studs and upgrade to the 7/16" studs and RR's when I bought the Pro Mags :eyerole It woulda cost me all of about $60 more for the new studs ad

Now if I want to do it, I got new 3/8 studs that I just bought, so another new set of studs, and $176 to rebuild the RR's to the upgrade (of course thats over half the original purchase price I paid 2 mos. ago) plus the cost of the builder to do the geometry.

Do y'all think I'm OK with the 3/8" ones or do I really NEED to upgrade to be safe? I'm starting to have a weak stomach over this stuff after all the $'s I've already spent. I wonder if the giant sucking sound is ever gonna end, or at least quite down for a while. I know it's never gonna be cheap, maybe just a little more dependable would be nice. There's not a lot that hasn't been replaced already. I was hoping for a little uninterupted enjoyment somewhere along the line.

There was about a half a thread or so missing from the stud. I found about a third if that that I could pretty readily ID. The rest, well I dunno. I hpe I don't find it the same place you did jena. I still haven't cut the filter open or strained the filter oil yet. Maybe I'll find it there.

Thanks for reading and joining in

 

[Ken]

I wonder if the giant sucking sound is ever gonna end, or at least quite down for a while.

Colin, believe me when I tell you that I know exactly how you feel. People tell me that it's normal though, things'll get better.

_ken

 

[bradfordsvettes]

the filter is the best place to find that lost piece my guess is if it is in the pan it will get stopped by the pickup screen.you would need some pretty big pieces to cause damage down below at the rods and crank. i have seen a lot worse than that without any apparent engine problems.some of the new trucks and vettes were dropping the needles out of the rockers.you just never know what you will find. engines are pretty forgiving considering the beating some of us give them:eek :crazy steve

 

[jenavet]

steve
i am not so sure i agree with that one......the theroy is,the bigger the piece that falls into the lower end,the less you have to worry about it.....but my machine shop told me the same thing you said....and a few passes later i had a 6 inch hole in my oil pan.......its like playing the lotto,moonunit has to weigh the effort of pulling this thing out and apart,clean all the crap out of her and get the geometry problems solved,or leave it in and hope he dosent loose the whole investment...thats why i have all the valleys in my motors screened now to prevent having to worry about pieces going south......my personal opinion?? pull this motor out,disassemble and clean it,check everything over,get a dial indicator on the valvetrain and get that set up correctly...then put her back in with the piece of mind that your major investment is still intact......as far as the 7/16...7/16 studs go,if its a fairly radical cam profile and you are gonna spin some rpms,i would replace them...if not,just make sure you have the hgood 7/16...3/8 studs...at worst,ask comp cams

 

[SPANISHVETTS]

I would tear her down and clean her up. It will save you $ in the long run. I called up Frankie after reading your post. He said that he puts 7/16¨ studs in every head he touches. He also said to be sure that you use harden guide plates.

 

[Moonunit 451]

These last two posts were more what I expected to hear. I have the question out on two forums and these are the first ones to suggest that I yard the motor. This is gonna be a tough one (getting more nauseated). I'll let ya know.

jena I'm running the standard torque set up 219, AFR 195's and SR 383, built auto trans, D44. So probly not a lot over 6,000 or so. Haven't even dynoed and final tuned yet.

 

[jenavet]

well.....i know its a tough decision. its alot of work pulling everything out and apart...but this is the way i reflect on it now.....i got a killer deal on a 406...i bought it brand new off a guy who was hurting for cash for 4500.00...he had it built for 9000.00...he had all the reciepts and i went through all the parts and the pricing was dead on...i could have dropped it right into my car,but to be safe,i had my machine shop tear it down and verify that the parts on the reciepts were actually in the motor and all looked good......they tore it down and found a couple of minor problems...i had to have the steam holes drilled,the block on one side had a stripped head bolt hole and the head on that side was warped...the seal for the belt drive was installed improperly...all minor stuff,but things that had to be done....i paid a total of 1200.00 in parts and labor to get her up to snuff.......so i had a 9000.00 motor for 5700.00 total...awesome deal!!!............10 passes later,i didnt go over valve lash and one loosened up and broke a lifter dumping pieces into the lower end.....i found most of the pieces,but several were still awol..........i went to the machine shop and dicked around with pulling it out or just replacing 1 valve a rocker and 1 lifter.......if i pulled it out,im sure the machine shop would have given me a bit of a break...im guessing i would have paid 500.00 parts and labor to tear it back down and regasket it etc....instead i bought the valve,rocker and lifter and gaskets for about 180.00...so 5700 plus 180.00=5880.00 total.........about 15-20 passes later i tossed a rod and on disassembly of the destruction,found that one of the small lifter pieces caused the mayhem...........so i needed a new block,new oil pan,the crank had to be repaired,i replaced 3 rods,2 pistons,all the bearings and rings,oil pump,4 valves,the heads had to be repaired,new valve springs,gaskets....i spent 3200.00 putting her back together and missed 1.5 months of racing.....so 5880.00 plus 3200.00=9080.00.....now my great deal has turned into a not so great deal......i learned my lesson...i had the oil returns all screened,i check valve lash before and after every race day,i change the oil every week...and if see anything that may even remotely resemble a problem...im buying beers for my brother and his freinds and this thing is coming apart!!

 

[Moonunit 451]

I'm listening jena, pretty well resigned :cry

 

[wallyknoch]

Possible guide retainer problem

Correct stack height on the valve springs to prevent coil bind, or valve guide to retainer may be the problem as the lift apparently became dead solid without necessary clearances. This can do a few things, bend pushrods, and break the rocker studs as the cam goes to full lift. Guide to retainer clearance has to be more than the total lift of the cam which has noting to do with the valve lash unless it was adjusted too tight. Just a loose valve adjustment would not normally break a stud as the clearance would be increased not tighter. Internally, as the piston comes to TDC the valves are closing therefore the engine is probably ok. A compression check would varify this. Without knowing more of your changes, it`s a good place to start.

 

[Moonunit 451]

Thanks wally, I'm gonna have a very well respected builder in the area take a look at the whole situation on Tuesday and go from there. I'm suffering from lack of knowledge and too much input right now.

I asked for the input and appreciate it, unfortunately I just don't know enough to make a decision based on it and there are conflicting views on some of the issues I've mentioned. Eyeballs of a pro should clear up some. I'll report back. And thanks everyone I gotta chill