What alloy does the MT9 engine use?

Are ya having a problem with your rig? We'll try to help. Share your tech tips and experiences here. Dr. Billy Glaser, author of the "Unofficial 750 Ural Service Manual" site myural.com, is moderating this section.
Forum rules
Here is the place for you to ask questions about or share your experiences about servicing or repairing your Ural or Dnepr. Please post topics concering modifications or accesories in the "Modifications and Acessories" section. Please post oil related questions in the "Oil Threads" section.
User avatar
Korto
Comrade
Comrade
Posts: 38
Joined: Thu Aug 09, 2018 7:31 am

What alloy does the MT9 engine use?

Post by Korto » Fri Aug 16, 2019 8:11 pm

I'm not very optimistic about anyone being able to answer this, but I was wanting a welder to weld flanges onto the (badly rounded off) exhaust ports of the cylinder head (so I can use proper steel bolts instead of aluminium thread, and what moron ever thought aluminium thread was a good idea?), and he refused because he didn't know what type of aluminium alloy it was and so it was too risky. And I have to respect that. He's a professional, accredited welder who presumably knows his business.

So, is there anyone here, with the qualifications to know what the welder needs to know, who knows what kind of aluminium alloy they used on the cylinder head of a 1972 MT-9?


Alternatively, anyone know any good solutions for rounded off thread that doesn't involve me having to buy a whole new cylinder head?
Australia, Newcastle. 1972 Dnepr MT-9... mostly... I think...

RC20
Hero of the Soviet Union - 2020
Hero of the Soviet Union - 2020
Posts: 2441
Joined: Thu Apr 19, 2018 11:59 am
Location: Anchorage AK

Re: What alloy does the MT9 engine use?

Post by RC20 » Fri Aug 16, 2019 8:53 pm

I can't begin to help you, possibly no one can as the alloys could be anything and if he is not confident enough in a general type rod, then a specific rod for that likely not available either.

I find it beyond belief they used aluminum studs.

Likely the only way would be a blown MT-9 head to test with.

You might query on the process as it does not sound like the aluminum allow is crucial

https://www.esabna.com/us/en/education/ ... -steel.cfm

Picture would help as it would seem you could drill out the old stud and install a steel one in place? Might not be seeing what you have.
Fear No Gravel
Formerly Owned: ( various rides on others)
Honda 90
2 x CB750K (one a true Japan Model flown to Hawaii by a P3 Orion Sub Patrol Aircraft!)
1 x CB700 SC ala Shaft Drive Nighthawk S (RC20 is the actual in house production Model)
1 x R80GS (ok to start with, learned to love it for what it was)
1 x CB450K

Current:
1 x 2019 cT Terracotta

What I Did (I quit June 2 , 2019)
Mechanic/Technician/Engineer: Electro Mechanical Systems

User avatar
Mr Wazzock
Hero of the Soviet Union - 2020
Hero of the Soviet Union - 2020
Posts: 6194
Joined: Wed Feb 01, 2017 8:22 pm
Location: Boston, UK
Contact:

Re: What alloy does the MT9 engine use?

Post by Mr Wazzock » Fri Aug 16, 2019 8:58 pm

Any chance of photos? I'm struggling to visualize it (well failing actually)
Mike H
2016 Ural cT, in glorious terracotta
(aka Oranzhevaya Opasnost, "The Orange Peril")

stagewex
Hero of the Soviet Union - 2020
Hero of the Soviet Union - 2020
Posts: 7542
Joined: Sat Jul 14, 2012 10:45 pm
Location: New Rochelle, New York

Re: What alloy does the MT9 engine use?

Post by stagewex » Fri Aug 16, 2019 9:22 pm

Perhaps the welder really doesn’t want the job? I don’t know either but there are plenty of aluminum heads and engines out there both car and motorcycle and I’ve never had a question like that and believe me, I’ve had a lot of stuff welded over the years.

Absolute best solution is helicoil or time-cert, both come in kits. Always a debate of which is better. Why add more of a failed and weak alloy (whatever it is). I have a few in my engine due to the wrong torque settings being included in the owners manual (lots of folks know about this). Done by dealer prep... not by me. Covered under warranty and the helicoils are super strong for steel vs. aluminum. I was tempted to do all of the head bolts but why tempt fate after getting the right torque specs?
Stagewex

Current Herd all running amok:
2019 Honda CRF450L (Elec Start)
2008 Vespa 150S (Elec & Kick Start)
2007 Ural Patrol (2WD, Elec & Kick Start)
2006 Honda "Big Ruckus" PS250 (Elec Start)
1991 Honda XR250L (Kick Start Only) *NOT running amok, out for Bottom & Top-End Rebuild.
1986 Yamaha BW200ES (Elec & Kick Start)

List what you "have", keep the others in your precious memory bank.

User avatar
sKiZo
Comrade General
Comrade General
Posts: 548
Joined: Mon Apr 22, 2019 11:31 am
Location: Western Michigan USA

Re: What alloy does the MT9 engine use?

Post by sKiZo » Fri Aug 16, 2019 9:58 pm

stagewex wrote:
Fri Aug 16, 2019 9:22 pm
why tempt fate after getting the right torque specs?
And for the benefit of those of us not in the know, what might those be? I've always gone with, tighten the bolts till just before they snap kinda thing.

PS - the soft studs might be similar to what they did on my Aurora Northstar. That has a lot of single use fasteners that actually stretch when properly installed and need to be replaced instead of re-used. Why? I'm told that's supposed to lock them in tight at lower torques without seizing over time due to major heat fluctuations. I doubt the object isn't to stretch them in a Ural (which is probably why they go fubar in the first place as torques are typically a lot lower than a standard bolt), but they do keep weight down while providing about the same strength as a grade 2 bolt while providing a LOT more vibration resistance.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Evil Kneivel? He got nuttin' on me!
2011 Ural T
Handicap mods include Raceway foot box, tank shifter w/reverse, and DIY rear brake pedal mods.

User avatar
Korto
Comrade
Comrade
Posts: 38
Joined: Thu Aug 09, 2018 7:31 am

Re: What alloy does the MT9 engine use?

Post by Korto » Fri Aug 16, 2019 10:30 pm

I don't know if helicoil do m48 x 2mm exterior thread repair

It's M48 x 2mm threaded pipe, one-piece head cylinder casting
Image

You stick the exhaust pipe in it, and screw the big nut over the top to tighten it
Image

So it ends up looking like this
Image

The thread on the pipe is rounded. The thread on the nut is also a bit rounded, but can be replaced. I want to weld a plate on the end of the threaded pipe, and another on the exhaust pipe, so I've got two plates butting against each other. Put an exhaust flange gasket between,
Image

and then use real bolts to bolt the exhaust and cylinder plates together
Australia, Newcastle. 1972 Dnepr MT-9... mostly... I think...

jeffsaline
Hero of the Soviet Union - 2020
Hero of the Soviet Union - 2020
Posts: 500
Joined: Mon Dec 14, 2015 12:04 am
Location: Rapid City, South Dakota

Re: What alloy does the MT9 engine use?

Post by jeffsaline » Sat Aug 17, 2019 9:40 am

Repairing the exhaust stub threads on the head is a common job on old airhead BMWs. If I was going to do some welding on the exhaust stub I would probably be using 4043 filler rod.

Best,

Jeff
Jeff Saline
2010 Gear Up
-Good, Fast, Cheap. Pick Two
-Just because something isn't true, no reason you can't believe it. Hub McCann Second Hand Lions
-Anything is possible if you don't know what you are talking about.

User avatar
jaybird
Order of Suvarov
Order of Suvarov
Posts: 3067
Joined: Thu Jul 01, 2010 4:41 am
Location: The foothills of the Forked River Mountains, West Barnegat NJ (Do It In The Pines!) 08005

Re: What alloy does the MT9 engine use?

Post by jaybird » Sat Aug 17, 2019 9:54 am

I would try cleaning up the threads on the head with a thread file, thread chaser, die, etc, and using a new nut with plenty of anti seize.
What you’re proposing to do will probably wind up costing more than a replacement head.
As far as the weldor and the alloy composition of the head goes, I would try someone else as the one you talked to either doesn’t want the job or doesn’t have the confidence to attempt it.
In my circle I see aluminum engine cases of unknown composition being welded all the time, most are quite valuable and some irreplaceable.
If the threads are that buggered, I would just replace the head in this case.
Good luck.

Happy trails,
Jaybird
2005 Gear-Up, Mr. Nat_ural 108,000+ Kilometers and counting
2013 Retro, Black beauty, AKA Lucky "13"
1995 Olive Tourist
1975 Enfield Diesel Bullet
2008 Enfield Bullet 500
1974 BMW R 75/6
Etc.

RC20
Hero of the Soviet Union - 2020
Hero of the Soviet Union - 2020
Posts: 2441
Joined: Thu Apr 19, 2018 11:59 am
Location: Anchorage AK

Re: What alloy does the MT9 engine use?

Post by RC20 » Sat Aug 17, 2019 12:42 pm

Ok, that is a new one on me. Low cost production approach.

If you can clean it up you need to use aluminum specific anti seize.
Fear No Gravel
Formerly Owned: ( various rides on others)
Honda 90
2 x CB750K (one a true Japan Model flown to Hawaii by a P3 Orion Sub Patrol Aircraft!)
1 x CB700 SC ala Shaft Drive Nighthawk S (RC20 is the actual in house production Model)
1 x R80GS (ok to start with, learned to love it for what it was)
1 x CB450K

Current:
1 x 2019 cT Terracotta

What I Did (I quit June 2 , 2019)
Mechanic/Technician/Engineer: Electro Mechanical Systems

User avatar
jaybird
Order of Suvarov
Order of Suvarov
Posts: 3067
Joined: Thu Jul 01, 2010 4:41 am
Location: The foothills of the Forked River Mountains, West Barnegat NJ (Do It In The Pines!) 08005

Re: What alloy does the MT9 engine use?

Post by jaybird » Sat Aug 17, 2019 12:57 pm

RC20 wrote:
Sat Aug 17, 2019 12:42 pm
Ok, that is a new one on me. Low cost production approach.

If you can clean it up you need to use aluminum specific anti seize.
BMW airheads utilized that design for years.

Happy trails,
Jaybird
2005 Gear-Up, Mr. Nat_ural 108,000+ Kilometers and counting
2013 Retro, Black beauty, AKA Lucky "13"
1995 Olive Tourist
1975 Enfield Diesel Bullet
2008 Enfield Bullet 500
1974 BMW R 75/6
Etc.

User avatar
Desantnik-VDV
Order of Lenin
Order of Lenin
Posts: 1097
Joined: Sun Dec 16, 2007 5:21 pm
Location: Los Angeles

Re: What alloy does the MT9 engine use?

Post by Desantnik-VDV » Sat Aug 17, 2019 2:07 pm

Exactly like a BMW airhead of 70's and 80's. I had a hard time unscrewing and removing that nuts. They were seized and like baked on both R80 and R100 when I was doing Ural heart transplants. But I was able to use old nuts with some aluminum anti-seize Permatex paste the one is used on spark plugs:
https://www.amazon.com/Permatex-81343-A ... 2548&psc=1

Also, a special wrench makes it easy removal and installation.
Alex
2007 GearUp - BMD (Боевая Машина Десанта)

The rest is just history.

rivers
Hero of the Soviet Union - 2020
Hero of the Soviet Union - 2020
Posts: 9668
Joined: Sat Jul 24, 2010 10:04 pm
Location: 48*N, 122*W

Re: What alloy does the MT9 engine use?

Post by rivers » Sat Aug 17, 2019 2:41 pm

Korto, I am NOT a mechanic or welder but suggest finding another alum welder. No clue on what alloy KMZ/IMZ used back in the day but you can bet it was the cheapest easiest casting method avail at the time. So on the exotic alloy scale...I'd explore the lower end. I've had lots of "old even older" alum mc castings welded/repaired and never had a problem with alloy content. Often done w/o question as to make/model year/alloy content. I'd guess for whatever reason your welder just doesn't want the job.
Next thought would be save your shop money trying to convert to flanged exh headers. The exh nut system you have was industry standard for decades. yup more maint but still worked well. "I" would try to fix what ya got before chopping off the spigots/buggering up other wise good useable heads. If the threads have serious deformities work them with a thread file best you can. Then smear the threads with valve lapping compound then work the nut back-n-forth to final match cut/shape the threads. Once done on assembly add a gasket or ring of asbestos etc rope in the seat of the finned nut. A thin dab of copper based anti-seize on the threads will aid in leakage prevention and later maint/removal. I done this method on many slip-ins (bmw/triumph/et al).
Slip-in headers are more maint than bolt-on but not bad or too often if you actually do it every few years or if you notice leaks or looseness. One of the key satisfaction factors is the integrity/surface of the exh pipe stub that goes into the head. Sure slip-in heads and exh pipes can be reworked to take later bolt-on connections but it's not cheap or quick if you're paying a shop to do it. You can always resort to that option if your spigots are seriously deformed and not salvageable. Give it a go. Good luck.
Joe
014 GU
"I'm lost but I'm making good time."

User avatar
Lmo
Hero of the Soviet Union - 2020
Hero of the Soviet Union - 2020
Posts: 5429
Joined: Wed Jun 10, 2015 3:19 pm
Location: Pismo Beach via So. Indiana

Re: What alloy does the MT9 engine use?

Post by Lmo » Sat Aug 17, 2019 3:09 pm

Korto, welcome to the forums.

Are the threads on the exhaust stub totally shot? The threads on my BMW R75/5 are in pretty bad shape but once cleaned up (both male & female) they hold well. I use an anti-seize compound on them when installing.

If they are totally shot something like this might be an option to check out; they are also available for Dnepr MT10/11/16 and Ural https://www.sternmutterersatz.de/index. ... ng-anfrage

Image
The old threads do not need to be complete, just enough for the clamp to grab onto.
Image

EDIT - Looks like about $200USD [177E]. You will easily have that much in repair work.
Hinweis:

Wenn Sie die Teile für ein anderes Fahrzeug benötigen, lassen Sie es mich wissen, vielleicht lässt sich eine Lösung finden.
Ich habe z.B. auch passende Teile für die Einzylinder mit M45 Gewinde oder die Simson AWO 425

Also folgendes wurde bereits realisiert:
52/40 BMW R100RS ('77-'78) und vermutlich Krauser 4V
52/38 BMW R80/100 ('70-'94)
48/36 BMW R45/65 & Dnepr/Ural Mil Varianten
48/37 Dnepr MT10/11/16 & Ural mit Wulst im Krümmer
48/41 Simson AWO 425 1-Zylinder
45/37 BMW R12 & R25 etc. Einzylinder
45/37y BMW R25/2 etc. Einzylinder

übersetzt/translated

Note:

If you need the parts for another vehicle, let me know, maybe a solution can be found.
I have e.g. Also suitable parts for the single cylinder with M45 thread or the Simson AWO 425

So the following has already been realized:
52/40 BMW R100RS ('77 -'78) and probably Krauser 4V
52/38 BMW R80 / 100 ('70 -'94)
48/36 BMW R45 / 65 & Dnepr / Ural Mil variants
48/37 Dnepr MT10 / 11/16 & Ural with bead in the elbow
48/41 Simson AWO 425 1-cylinder
45/37 BMW R12 & R25 etc. single cylinder
45 / 37y BMW R25 / 2 etc. single cylinder
More information > https://forums.bmwmoa.org/showthread.ph ... ead-repair
Lew Morris
Dnepr w/ '06 Ural Drive Train
C5 Power Arc
125/42 jets
Drilled slides/
.030" shims

1973 BMW R75/5 (original owner)
1947 HD FL (long gone, forever regretful)

User avatar
jaybird
Order of Suvarov
Order of Suvarov
Posts: 3067
Joined: Thu Jul 01, 2010 4:41 am
Location: The foothills of the Forked River Mountains, West Barnegat NJ (Do It In The Pines!) 08005

Re: What alloy does the MT9 engine use?

Post by jaybird » Sat Aug 17, 2019 3:20 pm

Lmo wrote:
Sat Aug 17, 2019 3:09 pm
Korto, welcome to the forums.

Are the threads on the exhaust stub totally shot? The threads on my BMW R75/5 are in pretty bad shape but once cleaned up (both male & female) they hold well. I use an anti-seize compound on them when installing.

If they are totally shot something like this might be an option to check out; they are also available for Dnepr MT10/11/16 and Ural https://www.sternmutterersatz.de/index. ... ng-anfrage

Image
The old threads do not need to be complete, just enough for the clamp to grab onto.
Image

EDIT - Looks like about $200USD [177E]. You will easily have that much in repair work.
Hinweis:

Wenn Sie die Teile für ein anderes Fahrzeug benötigen, lassen Sie es mich wissen, vielleicht lässt sich eine Lösung finden.
Ich habe z.B. auch passende Teile für die Einzylinder mit M45 Gewinde oder die Simson AWO 425

Also folgendes wurde bereits realisiert:
52/40 BMW R100RS ('77-'78) und vermutlich Krauser 4V
52/38 BMW R80/100 ('70-'94)
48/36 BMW R45/65 & Dnepr/Ural Mil Varianten
48/37 Dnepr MT10/11/16 & Ural mit Wulst im Krümmer
48/41 Simson AWO 425 1-Zylinder
45/37 BMW R12 & R25 etc. Einzylinder
45/37y BMW R25/2 etc. Einzylinder

übersetzt/translated

Note:

If you need the parts for another vehicle, let me know, maybe a solution can be found.
I have e.g. Also suitable parts for the single cylinder with M45 thread or the Simson AWO 425

So the following has already been realized:
52/40 BMW R100RS ('77 -'78) and probably Krauser 4V
52/38 BMW R80 / 100 ('70 -'94)
48/36 BMW R45 / 65 & Dnepr / Ural Mil variants
48/37 Dnepr MT10 / 11/16 & Ural with bead in the elbow
48/41 Simson AWO 425 1-cylinder
45/37 BMW R12 & R25 etc. single cylinder
45 / 37y BMW R25 / 2 etc. single cylinder
More information > https://forums.bmwmoa.org/showthread.ph ... ead-repair
Nice post Lew, that's helpful :cheers:

Happy trails,
Jaybird
2005 Gear-Up, Mr. Nat_ural 108,000+ Kilometers and counting
2013 Retro, Black beauty, AKA Lucky "13"
1995 Olive Tourist
1975 Enfield Diesel Bullet
2008 Enfield Bullet 500
1974 BMW R 75/6
Etc.

User avatar
Mr Wazzock
Hero of the Soviet Union - 2020
Hero of the Soviet Union - 2020
Posts: 6194
Joined: Wed Feb 01, 2017 8:22 pm
Location: Boston, UK
Contact:

Re: What alloy does the MT9 engine use?

Post by Mr Wazzock » Sat Aug 17, 2019 3:23 pm

OK I get it now, identical to the BMW screw on finned clamps. Never had a problem with these (I had an R80) apart from originals seized, had to cut slots in the finned nuts to loosen them. Replacements always went back on with copper grease. That ensured they could unscrew again.
Mike H
2016 Ural cT, in glorious terracotta
(aka Oranzhevaya Opasnost, "The Orange Peril")

Post Reply