Rajay M20F Exhaust & Turbo Overhaul Questions

[ZentRose]

I am beginning the process of overhauling my Turbo Normalized IO-360-A1A engine (invoice attached) since it is making metal and near TBO. The turbo has roughly 500 hours since last overhaul and the exhaust was last overhauled by Dawley aviation about 1300 hours ago. 

I emailed acorn about inspecting and repairing the exhaust and they requested part numbers from me (not in my logbooks and not certain where to get those). As far as I can tell from the log books, the past owners have sent the exhaust in when needed and it tends to last much longer than 1300 hours between OH. 

I am wondering what your experience has been with the life of the exhaust and turbo with the Rajay set-up? From the logs, it seems appropriate to leave the turbo, exhaust and wastegate alone since they are easily removed from the plane and currently in good shape with many more hours of serviceable life.  

Thank you

-Tom

 

 

 

[Ragsf15e]

51 minutes ago, ZentRose said:

I am beginning the process of overhauling my Turbo Normalized IO-360-A1A engine (invoice attached) since it is making metal and near TBO. The turbo has roughly 500 hours since last overhaul and the exhaust was last overhauled by Dawley aviation about 1300 hours ago. 

I emailed acorn about inspecting and repairing the exhaust and they requested part numbers from me (not in my logbooks and not certain where to get those). As far as I can tell from the log books, the past owners have sent the exhaust in when needed and it tends to last much longer than 1300 hours between OH. 

I am wondering what your experience has been with the life of the exhaust and turbo with the Rajay set-up? From the logs, it seems appropriate to leave the turbo, exhaust and wastegate alone since they are easily removed from the plane and currently in good shape with many more hours of serviceable life.  

Thank you

-Tom

 

 

 

Seems like a good price from a quality shop.  I’m no help on your exhaust, but I think id ask the engine shop for a recommendation and then send in the exhaust in.  Id want to start with as much a fresh engine as financially possible.

[M20F-1968]

Which system do you have, the Original Rajay or the M20Turbo system?

[N201MKTurbo]

I would clean and inspect the exhaust, if there is no metal erosion, I would put it back in service.

I would pull the turbine and compressor housings from the turbo and clean and inspect them. I wouldn’t mess with the wheels, other than inspecting them. If everything looks ok, I would put it back together and put it back in service. 
 

I would take the scavenger pump apart, clean and inspect it and replace the oil seal.

[ZentRose]

44 minutes ago, Ragsf15e said:

Seems like a good price from a quality shop.  I’m no help on your exhaust, but I think id ask the engine shop for a recommendation and then send in the exhaust in.  Id want to start with as much a fresh engine as financially possible.

I agree with this approach for peace of mind but also want to be diligent. I had set aside $50k for overhaul when I purchased the plane so there is room left in the budget but I don't want to spend if I don't have to .

[ZentRose]

53 minutes ago, M20F-1968 said:

Which system do you have, the Original Rajay or the M20Turbo system?

Original Rajay with manual wastegate. The exhaust tubes & wastegate have been rebuilt/replaced over the years according to logs so those parts are not original.

[ZentRose]

55 minutes ago, N201MKTurbo said:

I would clean and inspect the exhaust, if there is no metal erosion, I would put it back in service.

I would pull the turbine and compressor housings from the turbo and clean and inspect them. I wouldn’t mess with the wheels, other than inspecting them. If everything looks ok, I would put it back together and put it back in service. 
 

I would take the scavenger pump apart, clean and inspect it and replace the oil seal.

This is good advice, thank you 

[N201MKTurbo]

I have hound the best way to clean the exhaust tubes is to get a long 1/4 inch drill extender and chuck up a 2” or so round wire wheel and run it as far as you can down the tubes and get as much of the deposits as you can. Wear a mask or respirator while doing this. The deposits are lead oxide and lead bromide. Try to avoid breathing the dust and wash well before eating. After that you can bead blast them. The stuff deep around the bends is very difficult to get out.

I was thinking a drain snake might work, but I’ve never tried it.

[1967 427]

Also, in an attempt to keep your oil system as sterile as possible. I would replace all the hoses have the oil cooler overhauled, IRAN on the prop governor and prop inspected and cleaned.

[M20F-1968]

16 hours ago, ZentRose said:

Original Rajay with manual wastegate. The exhaust tubes & wastegate have been rebuilt/replaced over the years according to logs so those parts are not original.

The reason I asked is that the original Rajay exhaust and wastegate parts are essentially junk.  When you make new parts, have them made of the next available thickness stainless.  The wastgate can be, and should be considerably thicker.  At 500 hours the turbo should be OK.  The scavenger pump likely should be rebuild by someone who does them routinely.  They are very simple but if they fail you have lost your oil.  

John Breda

[N201MKTurbo]

4 hours ago, M20F-1968 said:

The reason I asked is that the original Rajay exhaust and wastegate parts are essentially junk.  When you make new parts, have them made of the next available thickness stainless.  The wastgate can be, and should be considerably thicker.  At 500 hours the turbo should be OK.  The scavenger pump likely should be rebuild by someone who does them routinely.  They are very simple but if they fail you have lost your oil.  

John Breda

It’s hard to imagine what could fail in the scavenger pump. At worst, they would slowly loose effectiveness. I have three EBay scavenger pumps of different vintages. They all look new inside. The only thing that seems to fail is the oil seal. New ones are $5.

[Gee Bee Aeroproducts]

I have made some silicone molded ducts for this installation per sample.

Baffle seals are the same as oem pattern.

 

i will add pictures later

i can only recommend Lycon in Visalia 

[M20F]

Main turbo for RayJay overhaul.  
 
I wouldn’t mess with the exhaust unless it is actually giving you a problem.  Mine as at least 2000hrs on the exhaust. 

[M20F-1968]

On 12/26/2024 at 12:15 PM, N201MKTurbo said:

It’s hard to imagine what could fail in the scavenger pump. At worst, they would slowly loose effectiveness. I have three EBay scavenger pumps of different vintages. They all look new inside. The only thing that seems to fail is the oil seal. New ones are $5.

I agree, but it is such an important part, I would just be sure that your work is done properly, with the correct seals and installed without damage to the seal.

John Breda

[N201MKTurbo]

1 hour ago, M20F-1968 said:

I agree, but it is such an important part, I would just be sure that your work is done properly, with the correct seals and installed without damage to the seal.

John Breda

Mine was leaking oil and it was getting on the vacuum pump. I replaced the seal twice and it wouldn’t stop leaking. I chucked the shaft in a lathe and polished the surface the seal rides on. It hasn’t leaked since.