Con-rod oiling holes

[groily]

But don't SRM often install their own (presumably higher-capacity) oil pump along with their rods with no holes at all? Or would that only be with the end-feed conversion?
It's all Greek to me . . .
So glad Markus I'm not the only person here who struggles regularly with AMC year-on-year oiling mods - other whole forums exist for the unravelling of those arcane mysteries and to keep us from mis-matching parts with terminal consequences. At least no issues over holes in rods, and equal oil distribution to both big end journals via the centre main bearing . . . .
Sounds so perfick - but weirdly enough BSA twins seem to work for rather longer between radical surgery despite their timing-side centric way of shoving the slime around.
What did Triumph have, on their plain bush engines? Did Mr Turner feel the need for an 'ole on the far end? If, that is, his piston pump actually had the oomph to get the oil that far anyway after all the exertion of pushing out the tit on the tell-tale plunger?

[beezalex]

A65's didn't start with larger oil pumps...only the later ones got bigger capacity...but they need it: Higher RPM (Bearing oil consumption goes up) and larger bearings I think are the major reason.  BTW, SRM A65 oil pumps are the same capacity as the later model stock pumps.

[MG]

So glad Markus I'm not the only person here who struggles regularly with AMC year-on-year oiling mods

Well, if you haven't got enough problems, you gotta go out and buy some.  

Some of the decisions the AMC engineers made are absolutely unintelligible to me, like omitting the pressure release valve in some years. I mean, we all know about the oil-tightness of our old girls, even when oil pressure does not exceed levels of 150 psi.
I'm rebuilding the engine with '59 crankcases and updated these to the latest specs (retro-fitted the release valve, drilling through the inlet camshaft tunnel to oil the lhs cylinder, etc.)

Actually I have incorporated everything that makes sense to me, time will tell how good my decisions were...


Recently I read somewhere (can't remember where unfortunately) that Bert Hopwood had designed his A7/A10 engine within only 10 days, including making all necessary drawings for manufacturing.
Incredible achievement, regarding how well it performed and for how long a time this concept did proove it's quality.

Hats off to Mr. Hopwood!  

Markus

[Stu55Flash]

Hi not stripped my engine yet, so don't know from first hand but not mentioned on here so far:


Service sheet 202 says that on models after ZA10-4712 for A10 and A7 from AA7-101 the crankcase is modified to supply oil to the camshaft trough and directed to the cylinder walls from here.

Also in the Haynes manual on page 26 its says that after 1951 the left hand con rod of all engines has a special drilling and it is therefore not possible to interchange the con rods. If they are interchanged the left hand big end bearing will be insufficiently lubricated.

So is there possibly an issue with pressure at the left hand big end if oil pressure is lost on the right hand side. To test this is there any difference between the left and right journals when measured?

Great discussion thread!

Stu

[MikeN]

So glad Markus I'm not the only person here who struggles regularly with AMC year-on-year oiling mods

Recently I read somewhere (can't remember where unfortunately) that Bert Hopwood had designed his A7/A10 engine within only 10 days, including making all necessary drawings for manufacturing.
Incredible achievement, regarding how well it performed and for how long a time this concept did proove it's quality.

Hats off to Mr. Hopwood!  

Markus

Markus,
  The above isnt quite correct,
 Im looking at the transcript of an interview between a journalist from "the motorcyle" magazine and BSA's Mr H Hopwood,Chief designer (Motor Cycles). he says that he was "in" on the design of the BSA Vertical twins but it was Mr H Perkins, Assistant Chief Designer who laid down the A7 engine and it was, in Mr hopwoods words, "Mr Perkins baby".
With support coming from Mr, D W Munro of the Technical department.
  They discuss the original A7 and although there is no mention of the con-rod hole ( I dont think the early ones had them. the rods were made from nickel steel), it does mention that the oil pump passes 126.6 pints per hour and the return pump passes 177 pph at 5000 rpm which may be of interest.
MN

[MG]

OK, so credit to all of these smart guys.