Jump to content


Best Octane for 1957 M72


  • Please log in to reply
21 replies to this topic

#1 Eastwest

Eastwest

    Active Member

  • Members
  • PipPip
  • 37 posts
  • Joined:28-May 17
  • Gender:Male
  • Location:Melbourne, Australia
  • Interests:Antiques, aviation, vintage vehicles. Good food and wine.

Posted 18 September 2017 - 02:27 PM

Hi.  In the process of tuning the bike.  I have been using 98% Octane.  Is that the best for this bike?  Here in Australia the choices are 98, 95 or 91%.  

Mark
Ps.  Have added a little more of the bikes progress to my project thread here.

#2 haj

haj

    Active Member

  • Members
  • PipPip
  • 96 posts
  • Joined:15-February 11
  • Gender:Male
  • Location:Copenhagen/Denmark
  • Interests:Dnepr, bicycles, computers, history.

Posted 18 September 2017 - 02:36 PM

The bike is made for something like 67 octane. so 91 should be fine.

I'm running 92 unleaded in Denmark, and it seems to be all right (It's been a while since I checked the valves though, and they are the ones that might like a bit of lead afaik)
--
Dnepr K750 1956 (it says on the polish papers, damn lies! must be from the 60's)
Living in cold Copenhagen/Denmark

#3 Eastwest

Eastwest

    Active Member

  • Members
  • PipPip
  • 37 posts
  • Joined:28-May 17
  • Gender:Male
  • Location:Melbourne, Australia
  • Interests:Antiques, aviation, vintage vehicles. Good food and wine.

Posted 18 September 2017 - 02:48 PM

View Posthaj, on 18 September 2017 - 02:36 PM, said:

The bike is made for something like 67 octane. so 91 should be fine.

I'm running 92 unleaded in Denmark, and it seems to be all right (It's been a while since I checked the valves though, and they are the ones that might like a bit of lead afaik)
Lucky I asked then.  Good point you make about running unleaded in this old girl.    I don't want to burn her out.  I wonder if that fuel additive is still available to make it leaded fuel or its equivelant.  Will contact some auto stores today.

Mark

#4 haj

haj

    Active Member

  • Members
  • PipPip
  • 96 posts
  • Joined:15-February 11
  • Gender:Male
  • Location:Copenhagen/Denmark
  • Interests:Dnepr, bicycles, computers, history.

Posted 18 September 2017 - 03:00 PM

Forum question;
My feeling is that lead (or additive) isn't actually that important (at least for the sidevalves) .. anyone else feel otherwise?
--
Dnepr K750 1956 (it says on the polish papers, damn lies! must be from the 60's)
Living in cold Copenhagen/Denmark

#5 Mike Goldthorpe

Mike Goldthorpe

    Russian Bike Nut

  • Members
  • PipPipPip
  • 471 posts
  • Joined:21-January 10
  • Gender:Male
  • Location:Auckland, NZ

Posted 19 September 2017 - 08:12 PM

I've been running my R50/2 BMW on 91 octane unleaded here in NZ.  Seems fine after 8 years....

#6 luca.stere

luca.stere

    Russian Bike Nut

  • Members
  • PipPipPip
  • 634 posts
  • Joined:27-February 14
  • Gender:Male
  • Location:Romania

Posted 20 September 2017 - 03:23 AM

I know an Ural M67 with more than 80.000km runing with 95 unleaded fuel with  no problems. Also, in Romania after 1990 we still had for 15 years old cars which have running with uleaded fuel up to 200.000km with no problems.

#7 Eastwest

Eastwest

    Active Member

  • Members
  • PipPip
  • 37 posts
  • Joined:28-May 17
  • Gender:Male
  • Location:Melbourne, Australia
  • Interests:Antiques, aviation, vintage vehicles. Good food and wine.

Posted 20 September 2017 - 04:25 AM

I remember when unleaded fuel was introduced.  It was such a big deal and everyone was adding chemicals to their fuel and rebuilding the top of their engines.

#8 luca.stere

luca.stere

    Russian Bike Nut

  • Members
  • PipPipPip
  • 634 posts
  • Joined:27-February 14
  • Gender:Male
  • Location:Romania

Posted 20 September 2017 - 04:39 AM

View PostEastwest, on 20 September 2017 - 04:25 AM, said:

I remember when unleaded fuel was introduced.  It was such a big deal and everyone was adding chemicals to their fuel and rebuilding the top of their engines.

Probably just fooling the consumers.

#9 Solly

Solly

    Russian Bike Nut

  • Members
  • PipPipPip
  • 132 posts
  • Joined:08-March 15
  • Gender:Not Telling

Posted 20 September 2017 - 07:47 PM

As I understood it was hard to get a lubricant to the then valve guides made of iron or steel of the like. So they added lead which wouldnt smoke or foul plugs. The guides of modern era are more self lubricating materials......hardened bronze or mixture of those kinds of metals. No more lubricant required. But I believe they still have some sort of additive to lubricate in tank fuel pumps and injector pintels.

#10 luca.stere

luca.stere

    Russian Bike Nut

  • Members
  • PipPipPip
  • 634 posts
  • Joined:27-February 14
  • Gender:Male
  • Location:Romania

Posted 20 September 2017 - 09:46 PM

View PostSolly, on 20 September 2017 - 07:47 PM, said:

As I understood it was hard to get a lubricant to the then valve guides made of iron or steel of the like. So they added lead which wouldnt smoke or foul plugs. The guides of modern era are more self lubricating materials......hardened bronze or mixture of those kinds of metals. No more lubricant required. But I believe they still have some sort of additive to lubricate in tank fuel pumps and injector pintels.

My father was a mechanic and told me that he learned at the mechanic school that the lead was to improve the qualities of the gas in order for the engine to run smoother and to prevent unwanted detonations. Also, in the '80 my father was instaling LPG sistems on cars and the LPG gas don't lubricate nothing and the engines was running well.

Me and my brothers we have cars with LPG sistems and the engines have many kilometers whithout any problems.

#11 Solly

Solly

    Russian Bike Nut

  • Members
  • PipPipPip
  • 132 posts
  • Joined:08-March 15
  • Gender:Not Telling

Posted 20 September 2017 - 10:33 PM

That is true....lead does have a cooling effect in the combustion chamber which could only reduce temperatures which cause predetonations. Not sure of the LPG thing. But do know when working for Ford that the Police cars that were running LPG or CNG seemed to hole out a piston unusally more often than other vehicles. We were pushed to put in synthetic oil.It did make a difference.

#12 luca.stere

luca.stere

    Russian Bike Nut

  • Members
  • PipPipPip
  • 634 posts
  • Joined:27-February 14
  • Gender:Male
  • Location:Romania

Posted 20 September 2017 - 11:25 PM

View PostSolly, on 20 September 2017 - 10:33 PM, said:

But do know when working for Ford that the Police cars that were running LPG or CNG seemed to hole out a piston unusally more often than other vehicles. We were pushed to put in synthetic oil.It did make a difference.

It was a problem from fuelling mixture, poor LPG mixture which result on blue flame with high temperature. The problem it was not the LPG or CNG itself.

#13 Bilge Keel Dave

Bilge Keel Dave

    Russian Bike Nut

  • Members
  • PipPipPip
  • 1,282 posts
  • Joined:28-January 04
  • Gender:Male
  • Location:Olympia, WA
  • Interests:Beautiful Wife, Beer, Bikes, Boats, Books, British Cars.

Posted 21 September 2017 - 09:59 AM

Tetraethyl lead is an octane booster, not a lubricant, it was introduced to gasoline in the 1920's and phased out in the 1970's because it ruins catalytic converters.
Another thing it does is to prevent micro adhesions between the valve seat and valves on some engines with cast iron heads and valve seats. The micro adhesions cause valve seat recession or excessive wear of the seats.
RAMCO Dnepr MT-16

#14 Solly

Solly

    Russian Bike Nut

  • Members
  • PipPipPip
  • 132 posts
  • Joined:08-March 15
  • Gender:Not Telling

Posted 21 September 2017 - 01:30 PM

I knew about the octane boost that it gave. Thought for sure it had a lubricant quality to it though. Could be wrong.

#15 Solly

Solly

    Russian Bike Nut

  • Members
  • PipPipPip
  • 132 posts
  • Joined:08-March 15
  • Gender:Not Telling

Posted 21 September 2017 - 01:31 PM

I knew about the octane boost that it gave. Thought for sure it had a lubricant quality to it though. Could be wrong.




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users