Leak Down Test (Don't Laugh!!)

Status
Not open for further replies.
And the game now is, what cam do I have?

I used a digital vernier, had the edge resting on the case & used the depth gauge & dropped it down to the back of one of the cam lobes & zeroed the vernier. Then I rotated the engine so the cam lobe was now at it's highest point & measured again.

I got a reading of 0.32" for an exhaust lobe, I think it's the standard 061084 cam??

It's not the most accurate way of checking the cam but it's the only way I have of measuring the cam!
 
Last edited:
Fast Eddie said:
Advice to apply take to rods is good.

Advice to remember to remove it is even gooderer
Click to expand...

More post-its all over the bike!! I tend to put post-its, strategically placed in my line of sight so I don't forget a step or a washer/nut etc!!

Not that anybody on this forum would leave tape on the conrods!!!

Pete Lovell told me a great story, he built a Norton race engine at short notice so things were hectic getting everything ready, when he was about to fit the barrels he couldn't remember tightening the conred bolts!! He was 99% sure he did BUT was not 100%. He made up a 'special' tool so he could get at the conrod bolts & check if they were tight, which they were!
 
Grumpy knob said:
I`ve got some heavy weight barrels on the shelf that measure out at about 890cc and would be interested to know what pistons might fit if you`ve come across these before.

http://s628.photobucket.com/user/skip-rat/media/Norton/IMG_2283_zpsdqqg1zgx.jpg.html?sort=3&o=7

Regards, Al.
Click to expand...

comnoz said:
Interesting. So the bore would be around 80MM with no separate sleeves? I only know of one large iron barrel built, and it was whittled from billet. Jim
Click to expand...

Yes, 80MM and no sleeves, I thought i`d added a couple more photos but apparently not, I`ll try again.

http://s628.photobucket.com/user/skip-rat/media/Norton/IMG_2285_zpszgyy57rm.jpg.html?sort=3&o=7
http://s628.photobucket.com/user/skip-rat/media/Norton/IMG_2281_zpsp1o4cgtn.jpg.html?sort=3&o=9

Sorry Click for impinging, I was distracted by thoughts of heavyweight jugs!
I use 4 blocks of wood, split plastic tubing around the rods (the type welding wires come in). I did have some own made ring clamps but just used aluminium lagging straps the last time as they were to hand and they worked fine.

Regards, Al.
 
click said:
And the game now is, what cam do I have?

I used a digital vernier, had the edge resting on the case & used the depth gauge & dropped it down to the back of one of the cam lobes & zeroed the vernier. Then I rotated the engine so the cam lobe was now at it's highest point & measured again.

I got a reading of 0.32" for an exhaust lobe, I think it's the standard 061084 cam??

It's not the most accurate way of checking the cam but it's the only way I have of measuring the cam!
Click to expand...

0.332" Inlet and 0.322 Exhaust is standard. Regards, Al.
 
A bit surprised that no one has mentioned the engine rebuild DVDs from the NOC with Mick Hemmings showing how to do things. He covers all these questions plus a lot of other stuff. I've stripped & rebuilt a number of different types of engines (most of them even ran afterwards :-) )but I still learned a lot from it. There is also a gearbox DVD as well.
The NOC also sell an engine video with John Hudson - good to watch, but no where near as good as the Mick Hemmings one.
 
click said:
Some guys have suggested fitting the pistons into the bores first then fitting the pistons to the rods, can't see how you can hold all this together while fitting the gudgeon pins!!

Fast Eddie had a great picture of a piston holder, (see below). I can see this being useful while lowering the barrels down but it would be fiddly getting the rings to spring into the bores or is it easier than I think?

How about the use of ring compressors?
Click to expand...

As a last resort, you could always just use the method in the service manual:)

Actually, I use ring compressors as in the picture, but I also use a plywood cutout to hold up the pistons, similar to Fast Eddies plastic plate. That does seem to work better than the two rods in the picture. The ring compressors I use are also a bit easier to remove than the style in the picture.

Leak Down Test (Don't Laugh!!)


Ken
 
Appreicate all the replies.

As I get older, I've learned to ask before I lift a hammer!!, even if I think I know what I'm doing!! Is this wisdom:rolleyes:
 
SteveBorland said:
A bit surprised that no one has mentioned the engine rebuild DVDs from the NOC with Mick Hemmings showing how to do things. He covers all these questions plus a lot of other stuff. I've stripped & rebuilt a number of different types of engines (most of them even ran afterwards :) )but I still learned a lot from it. There is also a gearbox DVD as well.
The NOC also sell an engine video with John Hudson - good to watch, but no where near as good as the Mick Hemmings one.
Click to expand...

Sure why would I get them when I have all of you ;) I'll get onto the NOC site & start ordering:) thanks for the reminder, I've been meaning to get them for yearso_O
 
The very best piston ring compressors I have ever used are 3" house drain pipe pipe plastic clamps from a DIY shop with a bit of 6mm studding and some wing nuts.
You can do them up as tight as you like ,tap the barrel down with a rubber mallet no problems at all.
I have used steel motorcycle type ones + car type ones but they don't come close to the gutter clamps for ease of use or for ease of removal, cheers
 
baz said:
The very best piston ring compressors I have ever used are 3" house drain pipe pipe plastic clamps from a DIY shop with a bit of 6mm studding and some wing nuts.
You can do them up as tight as you like ,tap the barrel down with a rubber mallet no problems at all.
I have used steel motorcycle type ones + car type ones but they don't come close to the gutter clamps for ease of use or for ease of removal, cheers
Click to expand...

That's a great tip, I see a trip to the DIY store tomorrow :-)
 
Do the rods come up out of the case far enough to permit just fitting the wrist (gudgeon) pins?
If Jim were to fit the pistons/rings and ship them back inside the barrels, could they be pushed to the bottom, leaving the rings in the bores, and just enough to expose the holes for the pins, suspending the whole barrel + pistons assembly while fitting the pins?
 
Mr. Rick said:
Do the rods come up out of the case far enough to permit just fitting the wrist (gudgeon) pins?
If Jim were to fit the pistons/rings and ship them back inside the barrels, could they be pushed to the bottom, leaving the rings in the bores, and just enough to expose the holes for the pins, suspending the whole barrel + pistons assembly while fitting the pins?
Click to expand...

Yes, and that would be the way I would assemble them.
I sell lots of rings to replace rings damaged by ring compressors. I just use my fingers. Jim
 
Just trying to keep up here. So you aren't going to break open the lower end? Does that mean that you have studied the balance factor issue and are happy with it or that you are ignoring it?

Sorry to ask. But someone has to!
 
rvich said:
Just trying to keep up here. So you aren't going to break open the lower end? Does that mean that you have studied the balance factor issue and are happy with it or that you are ignoring it?

Sorry to ask. But someone has to!
Click to expand...

No need to say sorry, it's the main reason I started this thread so questions like this are asked, thanks.

I'm working on this with Jim at the moment, I'm going to check with Pete L. what he would normally balance a crank at for the Norvil 920 kit with Ford pistons. Since the chap that built my bike worked for Pete, its a reasonable assumption he would have used what Pete uses. It might just be the standard balance of 52%.
 
Last edited:
Re assembly: What Fast Eddie says!

I have done it the same way multiple times - no drama at all.
 
click said:
No need to say sorry, it's the main reason I started this thread so questions like this are asked, thanks.

I'm working on this with Jim at the moment, I'm going to check with Pete L. what he would normally balance a crank at for the Norvil 920 kit with Ford pistons. Since the chap that built my bike worked for Pete, its a reasonable assumption he would have used what Pete uses. It might just be the standard balance of 52%.
Click to expand...

OK, I've been annoying Jim with a few emails back & forth with the piston weights etc. and he has worked out the balance factor based on a few assumptions and feels it should be fine and I'm happy with that.
 
Dances with Shrapnel said:
I see a paid trip to Ireland in your near future.
Click to expand...

As long as Jim didn't mind being crated up and spending 2-3 days being shipped from the USA to Ireland, we would of course ensure he had some water etc.

I can put a hammock in the garage so he can be with the bike 24/7 I can loan him my tools, a large hammer & an adjustable wrench of the finest quality o_O

My hand is waiting to be bitten off :rolleyes:
 
Status
Not open for further replies.

Similar threads

speirmoor
Compression Testing & Leak Down Testing Tools for Motorcycles
Replies
3
Views
1,286
Shelby-Right
Shelby-Right
jimbo
  • Locked
How does a Compression "Leak Down" tester work?
2
Replies
35
Views
16,111
JimNH
J
ILLF8ED
  • Locked
750 combat leak down test
Replies
3
Views
1,100
comnoz
comnoz
jseng1
  • Locked
Leak down test for lightweight pistons in Cmdo motor
Replies
10
Views
1,681
Hobot
Hobot
acadian
  • Locked
help narrowing down slight oil leak into left cylinder
Replies
8
Views
1,570
ashman
ashman
Back
Top