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I'm getting around to changing my wastegate, and I noticed that the wastegate plugs for the 1/8" NPT ports which won't be used have o-rings to seal instead of sealing by the NPT threads. I'm kind of sketched out by an o-ring sealing the unused ports on the wastegate considering how hot these things get and then adding boost pressure on top of that. I was always under the impression that NPT threads are sealed by the threads themself, but these plugs thread in very easily, and tightening them just squishes the o-rings.
This is regarding a VS racing wastegate, but I have a new genuine Tial wastegate for reference and it also has allen head 1/8" npt plugs for the unused ports. The only difference is that the Tial allen head plugs don't have o-rings, but they still don't seal by the threads and just bottom out if you thread them in the whole way. I can't imagine the plug would be airtight just bottoming it out considering the threads don't seal at all.
Is it ok to seal these plugs with o-rings, or maybe people use crush washers? The only option that makes sense to me would be to use a traditional npt plug that does actually seal by the threads (pictured in the background), but I figure there has to be a way people make it work with these allen head flush looking plugs that come with the wastegates.
I was thinking about using the crush washers, but from the packaging it's pretty clear those were intended to be used with the banjo bolt fittings. In theory I assume that would work though
If its an mvr it should be water cooled and the o rings should be fine
Interesting, appreciate the heads up and yea it's an MVR (44mm). It appears that the wastegate ports are m10x1 threads and while 1/8" NPT fittings will fit, it'll mess up the threads. Apparently, they're close enough that you can use a 1/8" NPT tap to rethread it to NPT threads so I'll be giving that a shot.
Interesting, appreciate the heads up and yea it's an MVR (44mm). It appears that the wastegate ports are m10x1 threads and while 1/8" NPT fittings will fit, it'll mess up the threads. Apparently, they're close enough that you can use a 1/8" NPT tap to rethread it to NPT threads so I'll be giving that a shot.
If it’s M10x1 threading, why not just buy a short bolt that is that threading, and put a washer (maybe a crush washer) on there, maybe with some sort of high temperature sealant?
I don’t know if I would want to re-tap it.
I’ve seen that the water cooling is optional on that wastegate. I have one, although I haven’t used it yet, but don’t plan on water cooling it. It isn’t required is it?
If it’s M10x1 threading, why not just buy a short bolt that is that threading, and put a washer (maybe a crush washer) on there, maybe with some sort of high temperature sealant?
I don’t know if I would want to re-tap it.
I’ve seen that the water cooling is optional on that wastegate. I have one, although I haven’t used it yet, but don’t plan on water cooling it. It isn’t required is it?
That's a good point, I guess I'm kind of worried how well the crush washer will keep it airtight under boost but I'm probably just overthinking things. Crush washers seem to work fine for sealing our oil pans, trannys, diffs, etc.
I don't plan on water cooling mine either and seems like it's just optional, more intended for setups like road race cars or engine bays with poor airflow. Someone correct me if I'm wrong, but it appears that you just leave those water ports open with nothing threaded into them if they're unused as it doesn't come with plugs for those. These are the water port to 4an fittings that come with the Tial wastegates
Right, leave the water ports open if unused. Can't remember if my gate has o-rings or not, but I used whatever came with the gate and haven't had an issue in 3+ years.
Right, leave the water ports open if unused. Can't remember if my gate has o-rings or not, but I used whatever came with the gate and haven't had an issue in 3+ years.
Same after 10+ years. And I'm using the water cooling ports.
When I installed my turbo I had found a small holes drilled in to the intake manifold on the back where they had been hard to see. Not sure what their original purpose was, but they needed to be filled. Being that they were on the manifold and rounded, I tapped them out and threaded some short bolts in with o-rings to accommodate for the non-flat surface. They have held strong and never leaked since. That being said, being that you have a flat surface, I would go with a crush washer. Highly doubt they will ever leak out even under boost. Teflon tape or locktite to be sure.
How to seal unused ports on wastegate?
