So I had this odd issue a while back but never really could figure it out. Today I had the hood up and was reving the engine with the throttle on the intake. I saw this which is clearly the sound i have been hearing. So question is, can i just put the bolts back in and be good? Ill test the actuators before, but am concerned with the port valves. How can i check those without removed the lim? Is it normal to push what i assume exhaust gas out like that? And how the heck did the bolts work their way out?

Thanks in advance

 

I just took apart my engine and found one port sleeve severly worn on the open end along with a loose pin!


What caused this to happen is unknown. The bolts were in place but the rod that connects to the sleeve was messed up where it goes over the pin.

The only way to check is to remove the pesky LIM, no way around it if you want to make sure of everything. Before I took it apart, the actuator moved freely, and I would have bet good money that everything was fine with the ports' functioning!

Does anyone lubricate the port sleeves with grease upon assembly? I was thinking a light coat of silicon oil but it probably would not last very long. A grease would last much longer, I do not want to have to pull off the LMI every couple of years to check the sleeves! Maybe after 5 years or so.

Run an eighth inch drill bit through the split air pipe fitting, mine was mostly clogged from the welding when it was made! So very little back pressure to move the actuators for 35 years! A quick check.

The sleeves had varnish deposits along with the ever present carbon soot buildup, both inside and outside. Is there any fuel system cleaner that will dissolve these deposits. If there is, how often should you use it, once a year, twice a year?

I know you have to rev the engine above 3800 rpms for the secondaries to start to open but how many rpms and what kind of load is needed to get the 5th & 6th ports to fully open? That kind of load would clean them up a bit along with a good fuel system cleaner! Revving the engine in neutral won't do anything, need to have that exhaust back pressure build up.

 

I removed the actuator rod and noticed this wear!



There was just the same amount of wear on the stop!

This wear came from these two pieces bumping into each other when the port was closed. Much more then a vibration.

There is quite a few degrees more rotation before the port begins to actually open.

Check your rod ends and let me know what you find?