Turbo Intake Misalignment?

[NWade]

All -

I've got my engine temporarily installed on the airframe and am trying to map out the accessories and Firewall; but I've run into a snag: I can't seem to get the Turbo to line up with the 45-degree intake coupler. Here are photos: https://flickr.com/photos/52684618@N03/sets/72157662622771163

I followed the latest manual instructions and trimmed 1.125" off of each end of the hose before fitting it up; and I fear that may have made the hose too short.

But in addition to that, the turbo inlet doesn't seem to match the angle of the intake hose - No matter how I tweak the intake manifold parts! I'm wondering if I need to "re-clock" the turbo to a more-vertical angle...

Any experienced AeroVee Turbo builders have sage advice to offer?

Thanks!

--Noel

[MichaelFarley56]

This is just my two cents Noel, so please take it for what it's worth!

When I fit my turbo into place, I didn't mess with "re-clocking" the turbo until it was actually resting on the exhaust manifold. I'd hate for you to try and fit everything now only to find that, after you fit the exhaust into place, that changes the location and/or angle of the turbo a little and you have to redo things.

So that's my first bit of advice. You don't have to install it permanently at this point, but try and get the exhaust manifold into place and then temporarily attach the turbo to it. (I hate saying that since fitting the exhaust manifold is probably the worst part of the turbo installation!) If you want to take it back off, don't use gaskets now and don't torque the bolts, but you want everything in place just like it will be when it's all permanently installed. You may not want to rely solely on the engine mount bracket; judging by your pics, I'm not sure you're holding the turbo in the exact right spot. I don't remember mine being that close to the engine mount tubing.

Anyway, once everything is in place, you can tweak the turbo a little by "re-clocking" it as necessary as well as slightly turning the intake T pipe that's on the other side of the silicone tube you've trimmed. You won't be able to move the top of the T pipe where it plugs into the two other tubes, but you will be able to "twist" it a little to get the proper angle between that pipe and the turbo in order to line up that silicone connector. I will warn you that it's a snug fit to get it all lined up, but you'll get it!

Does that make sense at all? I know that probably doesn't help much. If any other turbo guys want to jump in, feel free.

The plane looks great by the way Noel!

[wlarson861]

I agree with Mike, the first thing to do is put the exhaust pipes on since that will determine the mounting position for the turbo. After the turbo is mounted to the exhaust you will know whether you need to change the clocking of the compressor side to line up with the intake manifold. I needed to clock the compressor side back a few degrees to line it up better with the intake. Re-clocking isn't a big deal but you cant do anything until the turbo body is mounted in its final location. Don't forget the service bulletin for us tail dragger guys to re-clock the center bearing to vertical when the plane is parked, that will probably have to be done first then the compressor.

[NWade]

I agree with Mike, the first thing to do is put the exhaust pipes on since that will determine the mounting position for the turbo.

Thanks for the quick replies, gents!

Question: Is the turbo support bracket (that hangs down from the upper engine attach bolt) not good at locating the turbo? I get that the exhaust manifold is the #1 determinant, but I was hoping the support bracket was close enough... Sounds like it may not be? Did you guys find yourselves having to bend or tweak that bracket?

Thanks again,

--Noel

[wlarson861]

I didn't have to bend it but it was not an exact fit until the bolt to the exhaust and turbo were tightened. If I remember I had to hang the bracket on the accessory case loosely until I got the bolt loosely attached to the exhaust, then tighten both bolts. It is there to stabilize the turbo and keep it from flexing the exhaust pipes. I wouldn't rely on in to be in the perfect location to locate the other parts. The exhaust pipes and that bracket together determine the final placement of the turbo. Remember, even though they are welded in a fixture there can be some individual variance in the shape of the exhaust pipes.

[NWade]

Remember, even though they are welded in a fixture there can be some individual variance in the shape of the exhaust pipes.

Yes, I'm finding that out... Just jumped in the shop and put the exhaust on with a few bolts. Yipes! It sticks up a lot higher than I expected, and a lot higher than the turbo support bracket. Here's a photo: https://flic.kr/p/TKWogJ
[It may not be obvious in the photo, but the support bracket is about 1/2" *below* the exhaust mount!]

The turbo fits on the exhaust - barely - and is rubbing firmly on the firewall when in that position.

The mismatch between the turbo support bracket and the exhaust have me scratching my head a bit. I'm pondering using a couple of washers behind the engine mount rubbers, to space everything forward 1/8". That would help provide clearance between the turbo and the firewall. Further thoughts or advice are appreciated! I may write to Sonex Tech Support in the AM, too.

Thanks,

--Noel

[WaiexN143NM]

Hi noel,
Hows the turbo install coming? Did you add some washers to the engine mount rubbers to give some clearance? And the hose alignment? Looked thru your pictures, very nice build. I see u doubled up on the axel sleeve. Good idea. The only suggestion i could see is to reccomend installing the tracy obrien backing plates for the axel to brake caliper. You will be able to use 3 holes , better than the single tab, as some have snapped off. Keep at it! Thanks for the posts.

WaiexN143NM
Michael

[NWade]

Hi noel,
Hows the turbo install coming? Did you add some washers to the engine mount rubbers to give some clearance? And the hose alignment? Looked thru your pictures, very nice build. I see u doubled up on the axel sleeve. Good idea. The only suggestion i could see is to reccomend installing the tracy obrien backing plates for the axel to brake caliper. You will be able to use 3 holes , better than the single tab, as some have snapped off. Keep at it! Thanks for the posts.

WaiexN143NM
Michael

Thanks for the kind words, Michael.

I took washers from the washer kit that came with the AeroVee and put them between the engine mount and the rubber bushings, to space the engine forward between 1/16" and 1/8". That's seemed to provide just barely enough space to mount the turbo. However, the washers in my AeroVee kit are pretty thin and were deforming under compression when I tightened up the engine bolts; so I've got thicker, sturdier washers on-order from McMaster-Carr. I'm instructing at a big glider mentorship event for the Memorial Day Weekend, but with any luck they'll be waiting for me when I get home on Tuesday!

As far as the axles go: When I had someone weld on the extra steel sleeves, I also fabricated some steel tabs and welded them onto each axle (where the big bolt meets the tube), then I match-drilled them to the brake bodies & backing plate. So each axle has 2 clevis pins holding the brake system onto the axle - as I agree that a single pin seems prone to failure over time.

Will keep you posted on the progress as I get the turbo mounted!

--Noel