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ccowx Samba Member
Joined: May 15, 2015 Posts: 661 Location: Whitehorse Yukon
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Posted: Tue Aug 16, 2022 12:18 am Post subject: Mustache bar adapter strength? |
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I am putting a small stroker motor into a 1970 Westfalia and I just got word from the machine shop that the bus case I had hoped to use for that engine is possibly not going to work. I don't seem to have immediate access to a suitable bus case and might end up needing to use a standard bug case. I have an adapter for the mustache bar that attachs to the oil pump bolts and also has the mount on the case bolt. I am looking at around 100 hp in a stock westy with a full interior. Will the adapter hold that engine?
Thanks!
Chris |
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metz Samba Member
Joined: March 31, 2005 Posts: 279 Location: Norway
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Posted: Tue Aug 16, 2022 12:37 am Post subject: Re: Mustache bar adapter strength? |
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Yes. But if you're planning to run full-flow you will need to modify the adapter. _________________ 68 panel
64 ghia coupe |
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richparker Samba Member
Joined: November 24, 2011 Posts: 6982 Location: Durango, CO
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ccowx Samba Member
Joined: May 15, 2015 Posts: 661 Location: Whitehorse Yukon
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Posted: Tue Aug 16, 2022 6:48 am Post subject: Re: Mustache bar adapter strength? |
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Because it doesn't have the bosses in place to drill and tap them into. I can try to get another case that does have them but I was hoping to not have to buy a new case.
Thanks!
Chris |
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telford dorr Samba Member
Joined: March 11, 2009 Posts: 3555 Location: San Diego (Encinitas)
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Posted: Tue Aug 16, 2022 10:37 pm Post subject: Re: Mustache bar adapter strength? |
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Remember, ALL of the engine torque is going thru that adapter and those 4 little 8mm oil pump studs. Do you really want to do that? Just asking... _________________ '71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST) |
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ccowx Samba Member
Joined: May 15, 2015 Posts: 661 Location: Whitehorse Yukon
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Posted: Tue Aug 16, 2022 11:06 pm Post subject: Re: Mustache bar adapter strength? |
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True, I don't. However, looking at the world I live in, I don't appear to have immediate access to a good used bus case that has a dual relief oil system and late dog house oil cooler. I also don't have $2000 for a new one, even assuming it was available.
Good news is that I might be able to save my old case after all. It is a 1600 dp case with dual relief and everything I need. The machine shop is looking it over now.
Fingers crossed!
Chris |
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metz Samba Member
Joined: March 31, 2005 Posts: 279 Location: Norway
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Posted: Wed Aug 17, 2022 12:41 am Post subject: Re: Mustache bar adapter strength? |
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telford dorr wrote: |
Remember, ALL of the engine torque is going thru that adapter and those 4 little 8mm oil pump studs. Do you really want to do that? Just asking... |
The adapter is also fitted with a through-bolt in the opposite direction below the oil pump. Good luck breaking four 8mm studs with shear force. Been running this setup with a 110 hp engine for a couple of years without problems. _________________ 68 panel
64 ghia coupe |
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Earl Bay Samba Member
Joined: October 26, 2015 Posts: 91 Location: France 38
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Posted: Wed Aug 17, 2022 8:47 am Post subject: Re: Mustache bar adapter strength? |
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Interesting subject.
My engine builder refused to build me a 2074cc with such a bug case.
Allthough he never tried it before he wasn't willing to take the risk. |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51149 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Wed Aug 17, 2022 9:43 am Post subject: Re: Mustache bar adapter strength? |
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Much of it depends on your driving style, smooth easy clutch work and civilised throttle won't be a problem. But dumping the clutch for burnouts at every light will likely twist it off in no time at all. _________________ Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!
Слава Україні! |
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ccowx Samba Member
Joined: May 15, 2015 Posts: 661 Location: Whitehorse Yukon
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Posted: Wed Aug 17, 2022 10:05 am Post subject: Re: Mustache bar adapter strength? |
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I am getting the sense that, as I suspected, it is an "OK" solution, but not ideal. Here is a few thoughts:
-The wider spacing of the mounts is more important that the strength of the fasteners in my mind. Less leverage to twist and move.
-Strength wise, probably fine if you are not shock loading it, as BD says. I have other vehicles for drag racing, so no problem there. Long hills and freeway merging are my concerns.
-Leaks are a thought. That kind of flexing could be an issue, though I am not hearing it.
Thanks for the input guys! I have used one in the past with a very mild 1835 for years without problems, but I am upping the horses by about 40%, so it needs a re-think.
Chris |
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busdaddy Samba Member
Joined: February 12, 2004 Posts: 51149 Location: Surrey B.C. Canada, but thinking of Ukraine
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Posted: Wed Aug 17, 2022 11:59 am Post subject: Re: Mustache bar adapter strength? |
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The farm fabricator in me wonders if you could add braces between the rear exhaust port studs and the bar?, something that sandwiched between where the gasket goes and runs down and back to clamp or bolt to the bar.
Food for thought...... _________________ Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!
Слава Україні! |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Wed Aug 17, 2022 1:13 pm Post subject: Re: Mustache bar adapter strength? |
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if your case does not work out for you, ask Mike in Wasilla, AK if he has a bus case like what you need. his member name is BigBore _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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ccowx Samba Member
Joined: May 15, 2015 Posts: 661 Location: Whitehorse Yukon
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Posted: Wed Aug 17, 2022 3:33 pm Post subject: Re: Mustache bar adapter strength? |
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Definitely food for thought. I did find a picture somewhere of an adapter like what you describe.
And if I don't get good news from the machine shop, Bigbore might be my next phone call!
Thanks!
Chris |
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Abscate Samba Member
Joined: October 05, 2014 Posts: 22668 Location: NYC/Upstate/ROW
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Posted: Wed Aug 17, 2022 5:03 pm Post subject: Re: Mustache bar adapter strength? |
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What’s the shear on an m8 bolt? About 15 kN?
What’s the torque * moment arm/4 on the motor? I’ll bet it’s pretty comfortable _________________ .ssS! |
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Earl Bay Samba Member
Joined: October 26, 2015 Posts: 91 Location: France 38
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Posted: Thu Aug 18, 2022 12:29 am Post subject: Re: Mustache bar adapter strength? |
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for an M8 8.8 18.100 N, 10.9 26.600 N, 12.9 31.100 N
I had to look that up. Not an expert in this. I wouldn't use 8.8 in that place.
However sometimes the more flexible 8.8 is preferred over a 12.9 because 12.9 doesn't flex but breaks.
You certainly wouldn't use 8.8 to mount disc brakes. But I can't remember if they are 10.9 or 12.9 |
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Abscate Samba Member
Joined: October 05, 2014 Posts: 22668 Location: NYC/Upstate/ROW
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Posted: Thu Aug 18, 2022 3:44 am Post subject: Re: Mustache bar adapter strength? |
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metz wrote: |
telford dorr wrote: |
Remember, ALL of the engine torque is going thru that adapter and those 4 little 8mm oil pump studs. Do you really want to do that? Just asking... |
The adapter is also fitted with a through-bolt in the opposite direction below the oil pump. Good luck breaking four 8mm studs with shear force. Been running this setup with a 110 hp engine for a couple of years without problems. |
Sorry, I ghosted you on this.
Breaking a 14kN bolt with 100 Nm torque would be publishable
_________________ .ssS! |
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Earl Bay Samba Member
Joined: October 26, 2015 Posts: 91 Location: France 38
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Posted: Thu Aug 18, 2022 5:41 am Post subject: Re: Mustache bar adapter strength? |
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I'd love to have a profound reply to this.
I'm sure the math behind it isn't just "engine torque divided by 4 bolts that can each take 18kN so no problem"
I still have such a spare case but only a bus.
Maybe this would get more attention in the performance forum |
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germansupplyscott Samba Member
Joined: May 22, 2004 Posts: 7093 Location: toronto
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Posted: Thu Aug 18, 2022 7:13 am Post subject: Re: Mustache bar adapter strength? |
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Some crankcases have one boss that can be drilled/tapped, so in this situation you have the existing case boss, the through-bolt on the parting line below and the oil pump studs. It's still not ideal but sometimes you make do with what you have. Having the case boss drilled/tapped is a big plus.
One tip to using these case adapters is to weld nuts to the adapter plate so the fastenings can be blind, makes installation or removal of the hanger bar smoother.
_________________ SL |
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ccowx Samba Member
Joined: May 15, 2015 Posts: 661 Location: Whitehorse Yukon
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Posted: Fri Aug 26, 2022 11:08 am Post subject: Re: Mustache bar adapter strength? |
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Thanks Gentlemen, as always a lot of good responses and points made! My ultimate conclusion was that I could use the mustache bar adapter if I had to and likely it would be fine. However, me being me and the bus being my last and best of several, I decided to at least TRY to get a bus case, and I did. I got lucky and found a a nearly complete 1600 dual port, dual relief case. It even has 8mm studs. I plan to have it bored to fit the 92mm TW cylinders.
I have a question though. It is coded AES728699. It looks like it may have been planed and re-stamped at some point. What is the "S"? I also am not sure if the case savers and 8mm studs are original or not. If it was an "AE" code 71 bus engine it all makes sense, but I didn't think they had 8mm studs this early on. Could the "S" be some sort of waranty/re-issue block?
Thanks!
Chris |
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Abscate Samba Member
Joined: October 05, 2014 Posts: 22668 Location: NYC/Upstate/ROW
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Posted: Fri Aug 26, 2022 11:36 am Post subject: Re: Mustache bar adapter strength? |
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Earl Bay wrote: |
I'd love to have a profound reply to this.
I'm sure the math behind it isn't just "engine torque divided by 4 bolts that can each take 18kN so no problem"
I still have such a spare case but only a bus.
Maybe this would get more attention in the performance forum |
That’s actually how simple it is. How the bolts are threaded in is important of course, but the point that the torque of most any engine compared to the shear strength of a bolt is very low is valid _________________ .ssS! |
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