valves?

[olivera149]

i just recently cutoff my stock exhaust and replaced it with 3" pipe and a straight through muffler and now i am noticing a deep "woof" out the tailpipe. Truck still hasnt lost any power or fuel economy.

Here is someone elses' site that has similar sounds that i am having. clicky

the tailpipe sounds ike mine, except maybe little deeper woof, with more throttle the sound will follow and fade away about 1400 rpms.

incab i can hear some ticks that will occur during idle at the engine, and i pulled the air filter housing and nothing through the intake, so tomorrow i am gonna pull the valve covers and take a look under them. What should i look for, and whats safe to disassemble and inspect?

TIA

 

[argve]

typically if it's a woof out the exhaust then you have an exhaust valve that is not sealing all the way. Which could be from a worn valve guide allowing the valve to tip to the side during it's closing cycle which allows the cylinder to suck some of the exhaust back into the combustion chamber giving you the classic woof out the exhaust.

What you can do under the valve cover is to check for side to side movement of the valves but you really need to pop the valve springs off. In order to pop the springs off you need have a valve spring remover. Here is how you do it...

1st - remove valve cover

2nd - rotate engine so that cylinder under test is at TDC - meaning both valves closed and piston at the top of it's stroke. If the cylinder is not at the top of it's stroke then you will loose the valve down inside the cylinder and then you have to yank the head to gain access - read not fun...

3rd. Yank rocker arm assembly off cylinder in question. I want to say that there are two bolts that hold it in place but man it's been quite a while since I have been under the hood of an idi so don't quote me on that but it's a straight forward process.

4th - use valve spring compressor to compress the valve spring and then use a magnet to get the keepers off - valve keepers are little tapered locks if you will they are semi-circled and squeeze between the valve stem and the spring lock which sits on top of the spring.

5th. now remove the spring lock, spring and rotatar assembly keep in mind how this goes on because you will be putting it back together. Basically it goes.... like this... on the bottom is the rotatar, then comes the spring, then the keeper then the locks...

6th. Can you tip the valve stem side to side? if so then the valve guide is bad. You might have a small amount of movement but you should not be able to feel it with your hand in my opinion.

7th - Now reassemble that cylinder and move on to the next. I can't remember the torque setting for the rocker arm bolts but a quick look in any shop manual will show you. Now once you have reinstalled the assembly without the rocker hit the valve straight on with a rubber mallot or dead blow hammer - like you are opening the valve the reason for this is so that you will know if the valve locks are installed properly. because you will be compressing the spring and you want to find out now if the locks hold or not instead of finding out when the engine is running.... finding out via running is very very expensive...

 

[Russ]

Now once you have reinstalled the assembly without the rocker hit the valve straight on with a rubber mallot or dead blow hammer - like you are opening the valve the reason for this is so that you will know if the valve locks are installed properly.

Trav, won't that cause the valve to hit the top of the piston if it at TDC for that cyl? Possibly bending a valve if struck to hard? Just thinking out loud here.

 

[icanfixall]

The piston will be about .030 below the head and yes hitting the valve hard like your driving a nail will make it touch the piston so tap it lightly. These springs are only set for about 110 lbs of pressure. Its not like a big block with 600 lbs of spring pressure on inner and outer springs. You can push open the valves with your hand easily on our motors. Both intake and exhaust springs are the same spring. Kinda odd but it works.

 

[bikepilot]

You don't need very sturdy springs when you turn less than 4k rpm:lol

 

[TLBREWER]

i just recently cutoff my stock exhaust and replaced it with 3" pipe and a straight through muffler and now i am noticing a deep "woof" out the tailpipe. Truck still hasnt lost any power or fuel economy.

Here is someone elses' site that has similar sounds that i am having. clicky

the tailpipe sounds ike mine, except maybe little deeper woof, with more throttle the sound will follow and fade away about 1400 rpms.

incab i can hear some ticks that will occur during idle at the engine, and i pulled the air filter housing and nothing through the intake, so tomorrow i am gonna pull the valve covers and take a look under them. What should i look for, and whats safe to disassemble and inspect?


TIA

What you're describing is exactly the same thing I got when I put the 4" exhaust and straight thru muffler on my wife's truck. I suspect it had been there for awhile, just couldn't hear it with the stock exhaust. I'm still not done with the re-assembly, but the heads got a valve job, new guides, all exhaust valves replaced(bad), and all 16 springs replaced(bad). Head work cost me $452 plus $150 in gaskets. I also have done a lot of other "stuff" while it has been down.

Tom

 

[olivera149]

thanks for the info, the freakin wind picked up yesterday so i put off takin the valve covers off until today, thankfully the wind died down. I'm hopin its something simple, but you know how that goes,

I was gonna do a comp test at my buddies house, but we couldnt find it (they own and maintain livestock, potatoes, and a golf course) so i dont see the need in buying one when i have access to one for free, and that money can go towards the machine shop bill if needed.