Brown Truck Under the Knife Project - Engine

[Al_E]

Maybe the stem height was alitte higher on this valve.

 

[Jake S.]

If you put a dab of clay on top of the piston then put the head back on, rotate the motor slowly, then pull it apart, this will tell you what the piston to head clearance is. Or the piston to valve clearance.

 

[suv7734]

I'm going to go back and re-read the whole thread but IIRC there was an issue with the machine work done from the get-go. Didn't they surface the heads about 9 thou and then dress the valve stems?

 

[sle2115]

I'm going to go back and re-read the whole thread but IIRC there was an issue with the machine work done from the get-go. Didn't they surface the heads about 9 thou and then dress the valve stems?

Thinking I remember same...if they set the valve depth properly, then cut the valve stem properly, there shouldn't be an issue (of course the pre-cups would have to be reset as well).

Swear by looking at that bent pushrod in the picture, it looks longer...aren't they all supposed to be the same length? Been a while since I've been into one of these, but...???

 

[The Warden]

Yes, the push-rods are all supposed to be the same length.

My first guess would be that they didn't cut one of the valve stems, but I'm not an expert...

So sorry to hear about all of this, Sean...hopefully the piston/conrod didn't get any damage!

 

[f-two-fiddy]

Leak down test completed.
Result: FAILURE
Conclusion: Serious damage to #8 Exhaust Valve.
Repair: Remove cylinder head to determine extent of damage to head and other engine internals.


To answer your question yes the valve keepers are still on. I must say I have NEVER seen a pushrod bent that bad before. I can't believe I got that thing home like that. I do not believe there to be any holes in the piston. Because it is very apparent that all of the air is going out through the exhaust. I'd say thats enough of a conclusion to notify the machinist of the problem though.

Yeah, I think I'd still wait. Remove the offending valve, and measure it first.

 

[icanfixall]

That bent pushrod tells me the crank was not positioned correctly when you tightened down all the rockers but.... I really don't see any way the piston could have contacted the valve by floating the valves. A broken spring would show up right now. This is why when I install all the rockers I rotate the motor by hand till I feel it turn thru one complete revolution.

 

[Hybrid455]

Run a compression test paying close attention to what the glow plugs look like on the offending cylinders and are they all on the same bank? Maybe it's something simple like a bent pushrod, broken valve spring or broken rocker arm?

Took the passenger side valve cover off, the one where I could hear what sounded to be the valve train noise. Nothing out of line there. Everything is fine. This is the same cylinder that blew the head gasket that seemed to be making the valve train noise. But like I said I found nothing.
I'm not sure what to do now. I don't have money for a new set of injectors. I'm as broke as all get out. I just don't know what to do. If I had the money it would be a no brainer to buy a new set of matched injectors from Russ.

Question now is why did it bend the pushrod. If it was a clearance problem then I would have a hard time trusting any of the valves. It could also be a valve sticking, a weak or broken valve spring causing an early float or the valve not to close completely. Keep in mind that the hydraulic lifter will absorb a lot of movement. A valve stem would have to be really long to bottom out the lash adjustment and bend a valve. The idea that it didn't do it right away bugs me too. Did this happen while you were givin it a little hell? That would explain alot too. One of the reasons you shouldn't run a tight new engine to hard is heat. Heat grows parts. Heat sticks valves. I am an old racer too. A race engine only lives for a few thousand miles at best then its freshen up time or worse. This engine needs to live several hundred thousand miles. You shouldn't treat it like a race motor unless your prepared to blow it up like one. 950 degrees on your pyro is a heap when valve to guide clearances are really tight. It occurs to me again, it was an exhaust valve huh? Are you absolutely sure the valve didn't stick or a valve spring break? Sometimes a broken valve spring is really hard to see. Look closely at the base of the spring. A broken valve spring would let the valve hang open a little, then the lifter takes up the additional lash and POW! Are you absolutely sure the valve is bent? Just my 2 cents but if you do pull the heads I would have an independent person assess the situation. Check the valve stems for scoring as well as height on the offending cylinder. If it is found to be the machinists fault then I would not trust this guy again with my heads. I would ck both heads if you find the damaged one is clearanced improperly. Valve springs on the other hand.... well in my opinion new ones should have been installed on a high mileage expensive engine. If the machinist is at fault then have someone who knows what they are doing fix the heads and if he wont make restitution sue him.

 

[6 Nebraska IDIs]

Yea I got about 75-100 miles on the engine. I wasn't giving it hell when it happened I was just driving along, accelerating up a hill, I was below 2500rpm but right around there. Pyro was at about 800*, and boost was at 9psi if I remember correctly. It seemed to run perfectly before the incident. My brother said he could hear a faint clink clink clink as it ran, but I couldn't tell you for sure if it did or not because I no longer have 30% of my hearing. I can tell you he has the intake valves cut to a different height than the exhaust, the exhaust valves are the shorter ones though.
That valve is definitely open or something because I can't get that cylinder to hold any air at all. It all blows out the exhaust.
I had him test the springs, at least I told him to, and he told me they all checked out like new. This motor only had 90k original miles on it. Which is why I'm seriously wondering if he screwed up the required cut on the heads and then had to take another cut because for everything else to "be like new" it's really odd he had to take almost the max off of them to get a flat surface out of them. It just doesn't seem right to me. I don't know about you guys.
Anyway. Like everyone has said I hate pointing fingers, some of you are pointing them at me, and I've been kinda pointing mine at him.
I honestly don't see an improper torquing of the rocker arms being at fault because it would have ran like crap from the beginning had that happened. And actually I did turn the motor over atleast 2 revolutions by the time I got done assembling everything and it never bound up once that I could tell.
About the spring, I just really can't find a broken spot in it, but I do know sometimes you won't find a broken spring until it is taken off of the head.

 

[6 Nebraska IDIs]

Okay, just to make everyone clear on the pushrod deal. They are the same length. I just measured them. Had to do it with a string since the one is bent so bad, but they are the same length.

 

[sle2115]

Okay, just to make everyone clear on the pushrod deal. They are the same length. I just measured them. Had to do it with a string since the one is bent so bad, but they are the same length.

I figured they were, but trying to imagine the length from the picture (picture angles can cause weird things too) it looked as if it would have been longer if it were straight.

And just so we're straight...I'm not pointing any fingers...YET!

 

[Hybrid455]

I am not trying to point fingers either. Ive pulled some real ****** in my time and I'm trying to help you avoid them if I can. Its just really sucks. I'm hoping against hope for ya. Try removing the rockers on the next door cylinder if you haven't already. Try pulling up on the valve to determine for sure that it is up as far as it will go freely. Look at the exhaust valves they should be comparable in height. If they are that is a good thing. If the valve struck the piston while it was deep in the cylinder(stuck open) then the piston would have had to absorb more impact, the valve would have bent midway and will be riding lower then the rest now. Try popping the valve stem top with a rubber hammer. Be careful when you do this or you can send the keepers, retainer and spring flying. Hit the valve squarely and quickly trying not to hit the retainer. Listen to hear the valve snap in it seat. Recheck the leakdown to see if it has improved. You can also rock the valve stem gently side to side with a large screwdriver and ck for excessive movement. If inserts to repair the guides I have seen them chuck out in brand new engines and leave the valve extremely loose in the guide. This in turn causes the valve face to return to the seat off center and leak.

 

[6 Nebraska IDIs]

Lol no I didn't mean it like that. I don't want to point any fingers. But it sure seems fishy. It bothered me the whole time I was building the engine about this guys work on my heads after it took him so long and after all he did when I picked them up was ***** and complain about all the special measuring that had to be done to literally everything. I don't even think he pulled the precups out from what he told me. It sounded like he just milled them down with the rest of the head. But in all honesty I don't know what he did and did not do. That's part of hiring a professional, a person a like me is supposed to be able to trust them to do everything needed to make it work. After what he said when I picked them up I was worried about the heads from there on out.
I wasn't saying I don't like you guys pointing fingers at me, I don't care. I don't like having to point fingers at anyone. I'm just trying to figure this all out the same as the rest of you.
That valve being bent can't actually bend the rod can it?

 

[f-two-fiddy]

I think Your gonna have to pull the head. Something failed. Need to find out what failed in order to determine who, if anyone, is at fault.

 

[6 Nebraska IDIs]

Yea I know I'm going to have to pull the head. My dad is trying to talk me into doing it right now. The problem with pulling it right now is if the guy doesn't want to pay for anything, assuming he's at fault for it, then I have a motor that I may as well throw in the junk pile because it's open and I don't have any money to seal it back up. So I have a big decision to make.