71 norton top end break in now?

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iceteanolemon

iceteanolemon

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Hey all, I just got my jugs back from the metalizing shop. I had them clean them up and bore/hone them to .040....


I got some hitemp vht primer and gloss black and completed the prep and paint on them . They are looking really good and I would like to install this weekend some time.

I would like to se what tips are out there in the group for putting this stuff al together.

I have a new set of jcc pistons and they have a set of standard rings.



I still need to

Gap the rings
fit the pistons
fit the jugs
fit the head and all that....

If anyone has any tios shortcuts or clever things to share I would appreciate the input!! I know the secret to rolling the head on with the pushrods etc, I am looking for more tips that can streamline the process and help me not screw things up or work "the hard way".....
 
Re: Gathering top end tips!!! 71 norton....

Wash the bores with HOT water and dish soap, scrub vigorously with a nylon bristle brush (wifey's vegetable brush works great) and rinse thoroughly. This is a must to remove the particulate honing stone embedded in the cross hatch. SOLVENT WASH IS NOT EFFECTIVE AT REMOVING THIS MATERIAL. Have WD-40 on hand to oil them as they will rust IMMEDIATELY before your eyes. Put engine oil on soon after. Blow out oil passage and verify flow, clean lifter/pushrod cavities. Use Loctite 518 to seal the bottom (as a gasket dressing).
 
Re: Gathering top end tips!!! 71 norton....

iceteanolemon said:
Hey all, I just got my jugs back from the metalizing shop. I had them clean them up and bore/hone them to .040....


I got some hitemp vht primer and gloss black and completed the prep and paint on them . They are looking really good and I would like to install this weekend some time.

I would like to se what tips are out there in the group for putting this stuff al together.

I have a new set of jcc pistons and they have a set of standard rings.



I still need to

Gap the rings
fit the pistons
fit the jugs
fit the head and all that....

If anyone has any tios shortcuts or clever things to share I would appreciate the input!! I know the secret to rolling the head on with the pushrods etc, I am looking for more tips that can streamline the process and help me not screw things up or work "the hard way".....
Click to expand...


"standard rings" meaning... ? Not standard bore, obviously. I can tell you one peice oil rings did not work for me in a Trident. What a pain in the neck.

What piston clearance did you have your machinist hone to? Very important for longevity. A disturbing trend I see is the machinist "shooting for the middle of the tolerance" which is what a PRODUCTION machinist does. The "tolerance" however, in engine rebuilding, is a WEAR LIMIT and the low end is target, the rest being MINE to wear out. I see SO MANY rebuilt engines honed LOOSE, it sickens me. Half worn out, right out of the box.
 
Re: Gathering top end tips!!! 71 norton....

Get a buddy to help when raising /lowering the barrells and fitting pistons. Theyre heavy. And don't drop them on your/his foot !
 
Re: Gathering top end tips!!! 71 norton....

concours said:
iceteanolemon said:
Hey all, I just got my jugs back from the metalizing shop. I had them clean them up and bore/hone them to .040....


I got some hitemp vht primer and gloss black and completed the prep and paint on them . They are looking really good and I would like to install this weekend some time.

I would like to se what tips are out there in the group for putting this stuff al together.

I have a new set of jcc pistons and they have a set of standard rings.



I still need to

Gap the rings
fit the pistons
fit the jugs
fit the head and all that....

If anyone has any tios shortcuts or clever things to share I would appreciate the input!! I know the secret to rolling the head on with the pushrods etc, I am looking for more tips that can streamline the process and help me not screw things up or work "the hard way".....
Click to expand...


"standard rings" meaning... ? Not standard bore, obviously. I can tell you one peice oil rings did not work for me in a Trident. What a pain in the neck.

What piston clearance did you have your machinist hone to? Very important for longevity. A disturbing trend I see is the machinist "shooting for the middle of the tolerance" which is what a PRODUCTION machinist does. The "tolerance" however, in engine rebuilding, is a WEAR LIMIT and the low end is target, the rest being MINE to wear out. I see SO MANY rebuilt engines honed LOOSE, it sickens me. Half worn out, right out of the box.
Click to expand...


I mean standard rings as being regular rings (not two piece) but the rings were purchased with the pistons as a matched set for .040 over...

Dean Collinson told me to tell the machinist for allowing 5 thou clearance. Hopefully that works out... He was adament I let the machinist know this.
 
Re: Gathering top end tips!!! 71 norton....

As far as installing the head and push rods, make sure the rods are seated at the bottom, they should just drop in, but make sure they're not in a corner or something. I had good luck holding the rockers up with rubber bands, pushing the rods all the way up in the head, past the rockers, stuff some rags or hold them with more rubber bands, and rocking the head on from the left as I remember. It won't hurt to practice a few times and when you're ready for the gasket, you'll have a bit of experience behind you. Have a couple blocks of wood to hold the head above the cylinder while messing.

Then I tightened the 4 bolts next to the plug holes, not to torque, but just to get things in position. Watch the rods to center in the rocker sockets as you tighten and turn the engine. You will need a flashlight and maybe a mirror to see what is going on in there, make sure they are seated correctly in the rocker sockets as you tighten it down, and keep turning the engine as you do it. There should be no strange sounds when you get done. When you're confident things are good, torque the head down.

Others have their methods too. I didn't think it was a big issue, and I did it about 5 times just to make sure I was doing it right. It's not something you want to mess up.

Dave
69S
 
Re: Gathering top end tips!!! 71 norton....

DogT said:
As far as installing the head and push rods, make sure the rods are seated at the bottom, they should just drop in, but make sure they're not in a corner or something. I had good luck holding the rockers up with rubber bands, pushing the rods all the way up in the head, past the rockers, stuff some rags or hold them with more rubber bands, and rocking the head on from the left as I remember. It won't hurt to practice a few times and when you're ready for the gasket, you'll have a bit of experience behind you. Have a couple blocks of wood to hold the head above the cylinder while messing.

Then I tightened the 4 bolts next to the plug holes, not to torque, but just to get things in position. Watch the rods to center in the rocker sockets as you tighten and turn the engine. You will need a flashlight and maybe a mirror to see what is going on in there, make sure they are seated correctly in the rocker sockets as you tighten it down, and keep turning the engine as you do it. There should be no strange sounds when you get done. When you're confident things are good, torque the head down.

Others have their methods too. I didn't think it was a big issue, and I did it about 5 times just to make sure I was doing it right. It's not something you want to mess up.

Dave
69S
Click to expand...


Just reading the process you describe makes me want to go do it. I did my 850 a while ago but this was before looking for healp etc. i had fun and this time with the 750 I will be having fun as well... I will make sure those rods are seated. If not I wil bend em and that would suck.
 
Re: Gathering top end tips!!! 71 norton....

What sort of head gasket are you using ?

Something I've got into the habit of doing is spraying a new head gasket (lightly) with aluminium paint . Let it dry before use. Lot of oem gaskets for some other brands come like this new these days - the paint seems to cook to bond it to the head, and cylinder surfaces, and makes blowing a head gasket less likely. Far less likely. Of course, it makes separating them later on a shade more difficult.
 
Re: Gathering top end tips!!! 71 norton....

Rohan said:
What sort of head gasket are you using ?

Something I've got into the habit of doing is spraying a new head gasket (lightly) with aluminium paint . Let it dry before use. Lot of oem gaskets for some other brands come like this new these days - the paint seems to cook to bond it to the head, and cylinder surfaces, and makes blowing a head gasket less likely. Far less likely. Of course, it makes separating them later on a shade more difficult.
Click to expand...

I bought a stock base gasket for the jugs and a copper gasket for the head. i have some copper spray for the head gasket. I might use the base dry or add something on it.
 
Re: Gathering top end tips!!! 71 norton....

iceteanolemon said:
concours said:
iceteanolemon said:
Hey all, I just got my jugs back from the metalizing shop. I had them clean them up and bore/hone them to .040....


I got some hitemp vht primer and gloss black and completed the prep and paint on them . They are looking really good and I would like to install this weekend some time.

I would like to se what tips are out there in the group for putting this stuff al together.

I have a new set of jcc pistons and they have a set of standard rings.



I still need to

Gap the rings
fit the pistons
fit the jugs
fit the head and all that....

If anyone has any tios shortcuts or clever things to share I would appreciate the input!! I know the secret to rolling the head on with the pushrods etc, I am looking for more tips that can streamline the process and help me not screw things up or work "the hard way".....
Click to expand...


"standard rings" meaning... ? Not standard bore, obviously. I can tell you one peice oil rings did not work for me in a Trident. What a pain in the neck.

What piston clearance did you have your machinist hone to? Very important for longevity. A disturbing trend I see is the machinist "shooting for the middle of the tolerance" which is what a PRODUCTION machinist does. The "tolerance" however, in engine rebuilding, is a WEAR LIMIT and the low end is target, the rest being MINE to wear out. I see SO MANY rebuilt engines honed LOOSE, it sickens me. Half worn out, right out of the box.
Click to expand...


I mean standard rings as being regular rings (not two piece) but the rings were purchased with the pistons as a matched set for .040 over...

Dean Collinson told me to tell the machinist for allowing 5 thou clearance. Hopefully that works out... He was adament I let the machinist know this.
Click to expand...

Book says .0033" to .0047" clearance. I hate to be a buzz kill, but it's so predictable. Your piston ring end gaps will likely be out of spec as well, due to the bore size. :cry:
 
Re: Gathering top end tips!!! 71 norton....

I found it a lot easier to fit the rings to the pistons and install the pistons in the jugs on the bench. Be sure to insert the inner circlips. Then I used some 2x4 scraps to prop up the jugs on the cases, slide the rod ends up and install the piston pins. I put the pins in the freezer over night first. Warmed the pistons with a heat gun, slid right in. Put outer circlips on, done. Head was a bit of a fiddle. Shove push rods as far up as they will go and cram a shop towel between each pair to hold them. Once you have the head over the studs just pull the towels out. Then its a matter of carefully lowering the head while maneuvering the pushrod into place. A right angle pick like you use to remove o-rings is a handy tool for this.
 
Re: Gathering top end tips!!! 71 norton....

concours said:
Book says .0033" to .0047" clearance. I hate to be a buzz kill, but it's so predictable. Your piston ring end gaps will likely be out of spec as well, due to the bore size. :cry:
Click to expand...

Not a lot of difference between 5 thou and 0.0047" ?!!

When you see a worn engine, the clearances can get a LOT bigger than that. (and still run well !).
Lot better to have the pistons a shade loose than a shade tight too - a partial/seizure can spoil your day - big time.

Definitely check the ring end-gaps FIRST, by fitting loose into the bore.
Some rings can be too complete here - and need to be fitted for size.
No end gap can spoil your day too.
 
Re: Gathering top end tips!!! 71 norton....

Rohan said:
concours said:
Book says .0033" to .0047" clearance. I hate to be a buzz kill, but it's so predictable. Your piston ring end gaps will likely be out of spec as well, due to the bore size. :cry:
Click to expand...

Not a lot of difference between 5 thou and 0.0047" ?!!

When you see a worn engine, the clearances can get a LOT bigger than that. (and still run well !).
Lot better to have the pistons a shade loose than a shade tight too - a partial/seizure can spoil your day - big time.

Definitely check the ring end-gaps FIRST, by fitting loose into the bore.
Some rings can be too complete here - and need to be fitted for size.
No end gap can spoil your day too.
Click to expand...


You are correct... not a lot of difference. But, we ARE measuring TENTHS, and we ARE purposely machining a NEW rebuild OUT of tolerance. The "Lot better to have a shade loose than tight" is an old wives tale, retold by the unknowing. If a machinist can't hold the tolerance specified, you are IN THE WRONG SHOP. The thrust of this post is... wait for it... A COMMON MISCONCEPTION IS THAT A LOOSE PISTON IS LESS LIKELY TO SEIZE THAN A PROPER CLEARANCED ONE. That notion is FALSE. Of course, too tight (OUT of tolerance on the low side) will be bad, but increasing above proven clearances is of NO BENEFIT. Instead, quite the opposite is true. The heat put into the piston crown from combustion process must be transferred to the cylinder wall for dissipation by the finned casting. A LOOSER CLEARANCE WILL REDUCE THIS THERMAL CONDUCTIVITY AND RESULT IN HIGHER PISTON TEMPERATURES. At that point, during extreme conditions, such as sustained WOT operation, the piston can expand much more than design allows, then a seizure is MORE likely. The out of tolerance ring end gaps will allow increased blow-by gasses adding to the heating of the piston.
Some "experienced" engine builders use out of spec clearances to simply keep dopes from seizing a brand new engine from poor break-in methods. A SELFISH but all too common procedure. Motivated solely by $$$, they don't have to warranty the engine, and get to do it again soon. ($$$!!!)
Of course this all a moot point if a clattering parade bike is the goal, or rebuilds every 5,000 miles.

IT-L, please check your end gaps and report back!
 
Re: Gathering top end tips!!! 71 norton....

concours said:
Rohan said:
concours said:
Book says .0033" to .0047" clearance. I hate to be a buzz kill, but it's so predictable. Your piston ring end gaps will likely be out of spec as well, due to the bore size. :cry:
Click to expand...

Not a lot of difference between 5 thou and 0.0047" ?!!

When you see a worn engine, the clearances can get a LOT bigger than that. (and still run well !).
Lot better to have the pistons a shade loose than a shade tight too - a partial/seizure can spoil your day - big time.

Definitely check the ring end-gaps FIRST, by fitting loose into the bore.
Some rings can be too complete here - and need to be fitted for size.
No end gap can spoil your day too.
Click to expand...


You are correct... not a lot of difference. But, we ARE measuring TENTHS, and we ARE purposely machining a NEW rebuild OUT of tolerance. The "Lot better to have a shade loose than tight" is an old wives tale, retold by the unknowing. If a machinist can't hold the tolerance specified, you are IN THE WRONG SHOP. The thrust of this post is... wait for it... A COMMON MISCONCEPTION IS THAT A LOOSE PISTON IS LESS LIKELY TO SEIZE THAN A PROPER CLEARANCED ONE. That notion is FALSE. Of course, too tight (OUT of tolerance on the low side) will be bad, but increasing above proven clearances is of NO BENEFIT. Instead, quite the opposite is true. The heat put into the piston crown from combustion process must be transferred to the cylinder wall for dissipation by the finned casting. A LOOSER CLEARANCE WILL REDUCE THIS THERMAL CONDUCTIVITY AND RESULT IN HIGHER PISTON TEMPERATURES. At that point, during extreme conditions, such as sustained WOT operation, the piston can expand much more than design allows, then a seizure is MORE likely. The out of tolerance ring end gaps will allow increased blow-by gasses adding to the heating of the piston.
Some "experienced" engine builders use out of spec clearances to simply keep dopes from seizing a brand new engine from poor break-in methods. A SELFISH but all too common procedure. Motivated solely by $$$, they don't have to warranty the engine, and get to do it again soon. ($$$!!!)
Of course this all a moot point if a clattering parade bike is the goal, or rebuilds every 5,000 miles.

IT-L, please check your end gaps and report back!
Click to expand...
Old Britts does theirs between 45 and 5. I guess we will see if it is "clattering" when it goes live. Thanks for the input though, if it has any problems I will resleeve or go to 60 over and try again.

http://www.oldbritts.com/39_300801.html
 
Re: Gathering top end tips!!! 71 norton....

What ring gaps are everyone running with the JCC rings and pistons? I just measured and one of the rings comes to 20 thou....
 
Re: Gathering top end tips!!! 71 norton....

Old Britts does theirs between 45 and 5. I guess we will see if it is "clattering" when it goes live. Thanks for the input though, if it has any problems I will resleeve or go to 60 over and try again.

http://www.oldbritts.com/39_300801.html

It'll run fine. Like previously mentioned, they run well as the wear accumulates. Not trying to pry open a can of worms, just bringing it up for discussion.
 
Re: Gathering top end tips!!! 71 norton....

iceteanolemon said:
What ring gaps are everyone running with the JCC rings and pistons? I just measured and one of the rings comes to 20 thou....
Click to expand...

.010"
 
Re: Gathering top end tips!!! 71 norton....

concours said:
You are correct... not a lot of difference. But, we ARE measuring TENTHS, and we ARE purposely machining a NEW rebuild OUT of tolerance. The "Lot better to have a shade loose than tight" is an old wives tale, retold by the unknowing. If a machinist can't hold the tolerance specified, you are IN THE WRONG SHOP. The thrust of this post is... wait for it... A COMMON MISCONCEPTION IS THAT A LOOSE PISTON IS LESS LIKELY TO SEIZE THAN A PROPER CLEARANCED ONE.
Click to expand...

Measuring tenths ?? of what ??
The difference between 0.0047" and 5 thou is three tenths of a thou ?!!
The difference between a coarse crosshatch hone and a fine one is more than that...

Guzzi and BMW etc size their pistons in tenths of thous, never seen A,B,C on brit bike pistons ?? Hepolite piston sizes are quoted +/- 0.001 (1 thou)...
 
Re: Gathering top end tips!!! 71 norton....

concours said:
You are correct... not a lot of difference. But, we ARE measuring TENTHS, and we ARE purposely machining a NEW rebuild OUT of tolerance. The "Lot better to have a shade loose than tight" is an old wives tale, retold by the unknowing. If a machinist can't hold the tolerance specified, you are IN THE WRONG SHOP. The thrust of this post is... wait for it... A COMMON MISCONCEPTION IS THAT A LOOSE PISTON IS LESS LIKELY TO SEIZE THAN A PROPER CLEARANCED ONE.
Click to expand...

Old british bike boards are full of stories of rebores where the cylinders were bored too tight = watercooled car clearances - and subsequently had a tight piston or 2. Someone here bought a cheap Trident - when it warmed up, the engine became tight. Car clearances on the pistons....
 
Re: Gathering top end tips!!! 71 norton....

iceteanolemon said:
What ring gaps are everyone running with the JCC rings and pistons? I just measured and one of the rings comes to 20 thou....
Click to expand...
concours said:
.010"
Click to expand...

The general rule is 4 thou endgap per inch of bore.

That makes about 12 thou for a 750 Commando.
JCC rings would want to be something special to go with less than that ??
 
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