Could This Bend A Valve?

oz

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Jul 19, 2012

#1

• Jul 19, 2012

• #1

Greetings,
Long story short, dropped small metal object down intake runner #1. Turned engine to TDC #1, and then a full rotation to get to TDC w/ valves closed. Had to take the head off to get the part out.

After reassembled, did compression and then leak down and found that while compression on #1 is in the ballpark (down 10-15%), LEAK DOWN is 60% - only 40% of the pressure I'm putting in is staying in the cylinder - and most of the air is coming out the intake runner....

I took the rocker arms off just incase I had a geometry problem that was keeping the valve open and the results were the same.

Could closing the valve while a small object was in the way cause the valve to bend such that it won't seal?

If so, what are my options - new valve - any others?

THANKS!

 

Noobz347

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#2

• Jul 19, 2012

• #2

I don't think you have a bent valve. I think you have a valve seat or seal that is in poor condition.

Were it me, I'd take the offending head to the machine shop and have them check it out.

 

oz

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#3

• Jul 19, 2012

• #3

The heads only have about 1000 miles on them. They were built by PowerHeads with all new parts. I'm not sure if the seats were new though.
It didn't have this problem prior to 'the incident' with the small part going in so I'd be surprised if the seat or valve contact surface was bad.
Either way, I guess the head needs to come off. I'll take the intake valve off and see if it's even slightly bent. I'll be able to see if there's a seat problem as well.

Thanks!

 

Noobz347

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#4

• Jul 19, 2012

• #4

Yeppers... good luck.

...and here's hoping that little part didn't squeeze in there and damage a piston ring (my next guess).

 

oz

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#5

• Jul 19, 2012

• #5

Nope, it was sitting on top of the valve when I got the head off... right where I thought it would be.

It didn't occur to me that there was enough spring pressure to bend the valve's head if it closed on an object - but I should have...

FYI - the long and short is that I dropped a fuel injector down #1 runner and tried to use a spring loaded finger grabber thing to get it out. The fingers came off. One went in the cylinder... and aparently bent the valve when I rotated the engine to TDC while it was in the opening. <sigh>

 

Noobz347

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#6

• Jul 19, 2012

• #6

oz said:

Nope, it was sitting on top of the valve when I got the head off... right where I thought it would be.

It didn't occur to me that there was enough spring pressure to bend the valve's head if it closed on an object - but I should have...

FYI - the long and short is that I dropped a fuel injector down #1 runner and tried to use a spring loaded finger grabber thing to get it out. The fingers came off. One went in the cylinder... and aparently bent the valve when I rotated the engine to TDC while it was in the opening. <sigh>

Click to expand...

Ohhhh... it was ontop of the VALVE. I misread and thought it dropped down into the cylinder for some reason. So yeah... Pretty damned good chance it scored/damaged the valve seat. That's the weakest link in that area.

 

oz

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#7

• Jul 19, 2012

• #7

(expletive deleted) me! The little part that fell in was a V shaped spring steel set of fingers that go in the 'grabber'... if the valve closed on it, it would be on its side - so the metal that touched the valve and seat is very thin...
so probably scored seat AND bent valve! yay...

Is it safe to assume that my machinist can fix the seat?

 

Noobz347

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#8

• Jul 19, 2012

• #8

oz said:

(expletive deleted) me! The little part that fell in was a V shaped spring steel set of fingers that go in the 'grabber'... if the valve closed on it, it would be on its side - so the metal that touched the valve and seat is very thin...
so probably scored seat AND bent valve! yay...

Is it safe to assume that my machinist can fix the seat?

Click to expand...

He can replace the set or install a hardened seat if there are currently no press-to-fit seats installed. I still HIGHLY doubt that you bent a valve. You'll probably need that one cylinder machined to accept a seat and the seat installed and you'll be golden.

 

oz

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#9

• Jul 19, 2012

• #9

I'd hope it's just the seat too but 60% leak down makes me think it's the valve. I don't think little notches would flow that much - plus they'd whistle like a train...

 

Noobz347

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#10

• Jul 19, 2012

• #10

This is a tech thread gents.

 

Bullitt347

I have been doing it wrong this whole time

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#11

• Jul 19, 2012

• #11

I used Power Heads once, never again. Started the engine and withing 5 min. the heads have valves seizing in the guides. The rocker arm geometry was so bad that the heads were basically junk. Of course they said it was my fault, not their fault. They accused me of cranking the engine over for 15 min. without it starting so therefore the guides were not lubed. No warranty, no nothing. So that was the last time I ever dealt with them. It will be interesting to see what your machine shop says the condition of the heads are .

 

oz

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#12

• Jul 19, 2012

• #12

I had concerns about the valve springs at first but have not had any issues with the PowerHeads. They made very good power for what they are and I have a wide torque band that starts at low rpm.
After hitting my rev limiter a few times since putting them on without any issues, my concerns about the springs have lessened.
I'll repost after my machine shop looks at them.

 

oz

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Jul 20, 2012

#13

• Jul 20, 2012

• #13

I got the head off and took off the retainers and spring from the suspect intake valve and spun it in the guideand I can't see that it's bent but the seat is dark on one side - like there has been some exhaust slipping past it. The seat on the head has darkening on one side too.

I'm going to take it in tomorrow and have it checked out. If it's a bent valve, I'll just have a new one put in but if the valve is ok and it's just not seating properly, I'll probably pull the other head while I'm this far and have the machine shop check everything.

I may even have the spring seats cut to accept the springs that Comp Cams recommends for my XE270HR cam and ditch the ones that came on the heads from PowerHeads.

Thanks!