Wastegate stuck or was tightened to much by the rebuilder

[theman53]

no...in a word. The wastegate needs to function and if you run the screw in tighter than maybe a little past stock it will have creep. you will essentially have exactly what you did before with it not letting the gasses bypass. The ball and spring is the way to go if you have it.

[libbydiesel]

X2.  The stock adjuster is also the stop for how wide the wastegate will open.  You may be able to adjust the K14 wastegate to 11 or 12 psi but if you go higher than that with the stock adjuster the wastegate doesn't open enough at higher rpms and you'll get a spike.

[bbob203]

Ah makes sense! 

[libbydiesel]

So did you get it back together?  Did fixing the wastegate, running a ball/spring MBC and setting the boost 20ish or a little less cure the high rpm engine fart?

[bbob203]

Set the wastegate to open at 12-13 psi MBC set at 18psi with a slight spike to 19.5ish if i downshift and really punch it. egts exactly where they should be. This is a different car now  . The timing advance helped significantly esp with smoothing out the idle and clearing some smoke. The extra advance also helped with acceleration a bit too.

[libbydiesel]

Good, good, but does it still do the 4,000 rpm weirdness?

[bbob203]

Good, good, but does it still do the 4,000 rpm weirdness?

Couldn't get it to happen!

Most likely wastegate related. I hope!

[bbob203]

Took it out today and drove it about 60 miles around the city driving like it should be driven(safely of course) the whole time and it didn't let me down. Took it to 4000+ rpms more than a few times. Here's a little shot how i ended up running the MBC. There was a bolt stanchion on the back of the intake presumable for a heat shield on the pd with a corresponding reinforcement dimple on the inside so i trimmed 3/8 that was sticking out and drilled and tapped it for a 1/8 npt 90 degree street elbow and ran a barb off that for the MBC.

[libbydiesel]

If you were boosting well over 25 psi then likely the exhaust manifold pressure was significantly higher.  Maybe you were getting valve float after all. 

[bbob203]

valve float. 

should i be concerned with long term permanent damage?

[libbydiesel]

I'm not sure.  The obvious risk if the valves were floating from the EMP exceeding the closing force of the valve springs is that the pistons might have contacted the valves.  There may not have been any valve contact, tho and even if there was, it may not have been with enough force to damage the valve (the force holding them open would have been a springy cushion of exhaust pressure). 

[bbob203]

So i had a k0/ko4 hybrid in my hands last night. People call my k14 small. That is a small turbo..! People run these at 21 psi.. How?