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Discussion Starter #1
Sooo.. I pick my head up from the shop yesterday...the guy tells me all of my guides are good and he replaced my bad exhaust valve. Then he says oh....for some reason I had to seat than new valve. So I go to slap it on last night and something doesnt look right. I throw a straight edge across all the valves and the one he replaced seems longer(or is just seated farther in the head) than the others. It is #3 ex that is new. The 1 pic is with me holding a straight edge(ok its a saw:)sphss) on # 3 and 1...you can see the gap on 5 and 7. If I hold the edge so it touches 3 and seven...there is about a .020 gap under #1. I would pull the new and an old valve out and compare em to dbl check the shop....but I cant seem to get the cheapie spring compressor I got to do the job. Am I worried about nothing here....or should I be concerned?
bad job 1.jpg
 

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Sooo.. I pick my head up from the shop yesterday...the guy tells me all of my guides are good and he replaced my bad exhaust valve. Then he says oh....for some reason I had to seat than new valve. So I go to slap it on last night and something doesnt look right. I throw a straight edge across all the valves and the one he replaced seems longer(or is just seated farther in the head) than the others. It is #3 ex that is new. The 1 pic is with me holding a straight edge(ok its a saw:)sphss) on # 3 and 1...you can see the gap on 5 and 7. If I hold the edge so it touches 3 and seven...there is about a .020 gap under #1. I would pull the new and an old valve out and compare em to dbl check the shop....but I cant seem to get the cheapie spring compressor I got to do the job. Am I worried about nothing here....or should I be concerned? View attachment 120787
IMHO, i would be concerned about all the valve stems not being the same height!...i would think you would not get an accurate setting on the rockers when setting the clearance (loose/tight), thus, maybe damageing the cam :)...just sayin' my .02 cents FastRat
 

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Boat Nut
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Don't know the specifics, but seems he really buried that valve in the seat.... Any other damages to the valve besides the tip of the stem?
 

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Discussion Starter #4
Don't know the specifics, but seems he really buried that valve in the seat.... Any other damages to the valve besides the tip of the stem?
There were no signs of it being kissed by a piston or anything. I never saw it out of the head....didnt think to ask for the old part back.
 

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AKA Blownjet 468
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I would question the machinist- the shop I use would never have sent the head out in that condition- all seats should be the same height, as well
as the valve stems, (which is relative to the depth of the seat, of course) if it were a stocker p/up engine, I wouldn't worry about it, but in your
case-it should be right-I know you have lots of money invested;)

(I'll bet Steelcomp wouldn't send the head out looking like that either!)

:D
 

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Bostick Racing Engines
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Seems like he replaced the valve and may not have sunk the valve, (since there is no photo showing the combustion chamber side of the head, no way of telling for sure) but didn't bother to cut the stem on the new valve to the same heights as the other valves. I say may as you can do a light touch-up on a seat without sinking the valve that much. If this is the case, though it won't "damage" anything being .020 off... it does have an effect on your geometry which is less than benificial. Hopefull this is the case and he can simply just grind the stem and remedy it for you. If he did indeed sink the valve into the head that much, then hopefully he shimmed the spring accordingly, and even at that, you now have a valve that may have some shrouding. But, like I said, you really can't tell without seeing the combustion chamber side of the head.

Actually, many shops wouldn't even second guess this amount of difference as it could possibly be "in spec" technically. Though I am of the beilef that they create specs with a wide range so that hacks have some boundries... there is no reason why in this day and age with the equipment and tooling available that a fella with even the most basic competance shouldn't be able to keep the stem heights within .005 or tighter.... preferably dead on.
 

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Discussion Starter #7 (Edited)
Seems like he replaced the valve and may not have sunk the valve, (since there is no photo showing the combustion chamber side of the head, no way of telling for sure) but didn't bother to cut the stem on the new valve to the same heights as the other valves. I say may as you can do a light touch-up on a seat without sinking the valve that much. If this is the case, though it won't "damage" anything being .020 off... it does have an effect on your geometry which is less than benificial. Hopefull this is the case and he can simply just grind the stem and remedy it for you. If he did indeed sink the valve into the head that much, then hopefully he shimmed the spring accordingly, and even at that, you now have a valve that may have some shrouding. But, like I said, you really can't tell without seeing the combustion chamber side of the head.

Actually, many shops wouldn't even second guess this amount of difference as it could possibly be "in spec" technically. Though I am of the beilef that they create specs with a wide range so that hacks have some boundries... there is no reason why in this day and age with the equipment and tooling available that a fella with even the most basic competance shouldn't be able to keep the stem heights within .005 or tighter.... preferably dead on.
I am no genius ...but I even I can tell this valve is different(at least on the bottom) than the others.

Thanks for the response...I realize it isnt ideal....just not sure what to do about it at this point. I gave up on the machine shop that is 5 miles from my home...and drove an hour to get to this place. I am more frustrated than a pervert in a porn shop:)sphss Fwiw here is a pic of the combustion chamber.
chamber pic.jpg
 

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Maybe it just me. But that thing looks buried in the seat. Flow goes to hell when you do that.
Maybe Steel can shed some light on it.
Thought maybe the guy just installed a longer valve than the others, but this pic looks like he did in fact sink it.
I really like the line "FOR SOME REASON" I had to seat the valve. WTF, like he didn't know the reason?
Same guy that set up the P length the first time? You seriously need a new machinist.



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the padawan
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i second GN7, looks pretty burried to me, I was thinking the same, just take alittle off the top, you wont them all the same height valve geometry is gonna be off and lift at the valve will be different. i would be concerned about a machinist who acted like he had to do another step int he process...
 

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steelcomp was here
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Set your lash and run it. It's not unlikely that because the old valve was taking a beating, the seat might have been taking a beating too. It may have taken a bit of grinding to get it true again...it's hard to say. Stranger things have happened. Your machinist did right by not just throwing a new valve in the head without reconditioning the seat. That would have been hack. As long as he got the spring installed height right, and he had good reason to sink the valve, there's nothing wrong here. I would not arbitrarily grind the other seats just to get the valve depths the same. NOt on a repair. That just takes life out of the heads...an unnecessary valve job...for no reason. If you're worried about the chamber being bigger/changing the compression...you're talking about .9 cc. @ .020" depth change. The rest of your chambers might not even be that close to eachother. As far as geometry...pushrods come in .05 incriments, so .02 @ the valve is nothing. As far as grinding the tip of the valve... I wouldn't do it to one valve to get the tip heights the same. Then, if you ever do send the heads in for reconditioning, you have one short valve.
If this was a hard core race head that was sent in for repair, it would go out that same way. If it was sent in for reconditioning; guides checked, fresh valve job on all seats, new valves or face the old ones, etc...then yes, you'd take the time to inspect everything and get everything back to zero, but for a deal like this, the engine isn't going to know the difference. :)hand
 

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steelcomp was here
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Maybe it just me. But that thing looks buried in the seat. Flow goes to hell when you do that.
Maybe Steel can shed some light on it.
Thought maybe the guy just installed a longer valve than the others, but this pic looks like he did in fact sink it.
I really like the line "FOR SOME REASON" I had to seat the valve. WTF, like he didn't know the reason?
Same guy that set up the P length the first time? You seriously need a new machinist.
Unfortunately the justification for sinking the valve can never be proven at this point. The flow may not go to hell, although it sure doesn't help it to have an ex valve sunk. The valve job probably isn't ideal either, but so what are you going to do... ruin the flow on 7 other cylinders just to get them all the same? :)bulb
 

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Discussion Starter #13 (Edited)
Set your lash and run it. It's not unlikely that because the old valve was taking a beating, the seat might have been taking a beating too. It may have taken a bit of grinding to get it true again...it's hard to say. Stranger things have happened. Your machinist did right by not just throwing a new valve in the head without reconditioning the seat. That would have been hack. As long as he got the spring installed height right, and he had good reason to sink the valve, there's nothing wrong here. I would not arbitrarily grind the other seats just to get the valve depths the same. NOt on a repair. That just takes life out of the heads...an unnecessary valve job...for no reason. If you're worried about the chamber being bigger/changing the compression...you're talking about .9 cc. @ .020" depth change. The rest of your chambers might not even be that close to eachother. As far as geometry...pushrods come in .05 incriments, so .02 @ the valve is nothing. As far as grinding the tip of the valve... I wouldn't do it to one valve to get the tip heights the same. Then, if you ever do send the heads in for reconditioning, you have one short valve.
If this was a hard core race head that was sent in for repair, it would go out that same way. If it was sent in for reconditioning; guides checked, fresh valve job on all seats, new valves or face the old ones, etc...then yes, you'd take the time to inspect everything and get everything back to zero, but for a deal like this, the engine isn't going to know the difference. :)hand
Ok...thanks. Now all I am worried about is the spring height thing.:)sphss I don't see any shims...guess I can call him in the morning and ask. I think you are spot on in that he didn't go out of his way to f my head up....said that one valve needed it and the rest didn't. I'd like to think this guy new what he was doing....I am running out of machinists with in driving distance.lol :)grn
Edit; holy chit..I just keep finding more f'd up chit. I am outside thinking about dropping my head on...look down at one of my head studs...I'm like wtf....is that a broken off alan head. Sure as shit....whacked the stud one time with an old push rod and it fell right out....geezus.
head stud.jpg
 

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steelcomp was here
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I guess I was ASSUMING the seat wasn't THAT bad that it required that much grinding. Your right, you can't take your problem out on the other cylinders. The only other 2 fixes would be a new seat, (ouch) or a 1.90 valve:)sphss.
I agree, at this point, regardless of why, I would run it.

Next question? Is the spring stack the same?
At this point in the game, that's really the only variable.
 

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steelcomp was here
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Ok...thanks. Now all I am worried about is the spring height thing.:)sphss I don't see any shims...guess I can call him in the morning and ask. I think you are spot on in that he didn't go out of his way to f my head up....said that one valve needed it and the rest didn't. I'd like to think this guy new what he was doing....I am running out of machinists with in driving distance.lol :)grn
Edit; holy chit..I just keep finding more f'd up chit. I am outside thinking about dropping my head on...look down at one of my head studs...I'm like wtf....is that a broken off alan head. Sure as shit....whacked the stud one time with an old push rod and it fell right out....geezus.
View attachment 120882
Spring shims would be under the spring cups and not visible...if done right, but it wouldn't hurt to ask. ;)
 

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Steel is correct, the shims will be under the spring cup. Looking at you previous pics from the rocker geometry thread, it looks like you can get a machinist rule in there and measure from the top of the spring cup to the top of the spring(under side of the retainer). It if its close the others, your good. If it doesn't have shims, the spring will be taller by the same amount the valve tip is higher.

Everything I look at on this deal says you lash got loose. Top of the valve beat up, valve seat beat up. When the lash get real loose, instead of the cam opening things "gently", things get hammered open, and the valve slams shut hard enough to bounce. Maybe more than once. Take a good look at that cam lobe, and if the lifters are still in order, the lifter as well.
But something tells me the lash got pretty loose before you kicked the PR.

I know its just me, but I can't figure out what I am looking at here. I understand what you said, just can't visualize a broken stud from that pic. Does it have the nut screwed on to it? whats the white dot in the center? Whos stud is it?




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Discussion Starter #18
Steel is correct, the shims will be under the spring cup. Looking at you previous pics from the rocker geometry thread, it looks like you can get a machinist rule in there and measure from the top of the spring cup to the top of the spring(under side of the retainer). It if its close the others, your good. If it doesn't have shims, the spring will be taller by the same amount the valve tip is higher.

Everything I look at on this deal says you lash got loose. Top of the valve beat up, valve seat beat up. When the lash get real loose, instead of the cam opening things "gently", things get hammered open, and the valve slams shut hard enough to bounce. Maybe more than once. Take a good look at that cam lobe, and if the lifters are still in order, the lifter as well.
But something tells me the lash got pretty loose before you kicked the PR.

I know its just me, but I can't figure out what I am looking at here. I understand what you said, just can't visualize a broken stud from that pic. Does it have the nut screwed on to it? whats the white dot in the center? Whos stud is it?
Its a crappy pic...its a pic of and alan head broken off in my head stud. The tip of the valve got buggerd up 2 years ago when I busted a rocker and the stud girdle held it together for a bit(should have known better). The valve tip looks worse now than it did then. I may edit in a pic of the broken rocker tomorrow. Its at work...
 

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the padawan
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i agree grinding the head of the valve will shorten it next go around, however, valves head north... so WTF, he's just going to run it till the engine starts missfiring cause the valve already re-burried itself into the head.... either way good luck... For the stud, I like GN7...totally confused, my head studds onlly have a 4 way hex to install them, so he must have broke it off or I am missing something.
 
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