Crunchies on the drainplug %^^&*&(
- Thread starter comnoz
- Start date
- Status
- Joined
- Dec 10, 2008
- Messages
- 7,253
Danno said:
I fully enclosed the camshaft except for the area around the lifters once.
I used a steel tube and machined the cases to slide it in. Epoxied it in place. It collected any oil that came down around the lifters. Looked great.
The camshaft failed...
There is a lot of oil flying around in the cases.
comnoz said:
If you changed the rings last summer, I believe you cleaned pistons too. For what we can see on the picture, no carbon build up under even the top ring, looks like they are doing the job, no? And as you stated, the oil consumption is coming from somewhere else, valves guides?
- Joined
- Dec 10, 2008
- Messages
- 7,253
NKN said:
The cylinder head has been pressure tested with dye. There are no problems there.
The leakdown tester tells the story. When the crank is on the compression stroke the leakdown percentage is moderate at about 10%
If I rotate the crank past TDC to the power stroke the leakdown jumps to over 35%.
The blowby is evident in the oiltank also. I have had to keep the oil level lower than normal to keep the oil from blowing out of the tank vent.
I also suspect the excess blowby is partially responsible for my oil oxidation problem. Jim
The cylinder head has been pressure tested with dye. There are no problems there.
The leakdown tester tells the story. When the crank is on the compression stroke the leakdown percentage is moderate at about 10%
If I rotate the crank past TDC to the power stroke the leakdown jumps to over 35%.
The blowby is evident in the oiltank also. I have had to keep the oil level lower than normal to keep the oil from blowing out of the tank vent.
Jim,
Please forgive my ignorance. I wonder why the leakdown tests of 10% on compression and 35% on power stroke points to something other than rings.
Thanks,
Ed
The leakdown tester tells the story. When the crank is on the compression stroke the leakdown percentage is moderate at about 10%
If I rotate the crank past TDC to the power stroke the leakdown jumps to over 35%.
The blowby is evident in the oiltank also. I have had to keep the oil level lower than normal to keep the oil from blowing out of the tank vent.
Jim,
Please forgive my ignorance. I wonder why the leakdown tests of 10% on compression and 35% on power stroke points to something other than rings.
Thanks,
Ed
comnoz said:NKN said:
I believe you took off pin's circlip? Because from here it looks like the pin rubbed a little against the barrel.
There are no circlips. Those are aluminum buttons that locate the pin. Jim
Hi Jim, I've just had a circlip let go and make a mess of the bore that'll need a rebore. Your aluminium buttons for Gudgeon (wrist) pin retention, did you consider teflon buttons?
- Joined
- Dec 10, 2008
- Messages
- 7,253
willy mac said:comnoz said:NKN said:
I believe you took off pin's circlip? Because from here it looks like the pin rubbed a little against the barrel.
There are no circlips. Those are aluminum buttons that locate the pin. Jim
Hi Jim, I've just had a circlip let go and make a mess of the bore that'll need a rebore. Your aluminium buttons for Gudgeon (wrist) pin retention, did you consider teflon buttons?
I have used many Teflon buttons in race engines. They have to be renewed every so often -which is fine in a race motor.
For street use -aluminum buttons last as long as the piston. Jim
- Joined
- Apr 21, 2015
- Messages
- 322
No it is NOT overkill to posaitively oil feed the cams. That useless lamp of alloy beneath your cam USED to be when Mr Hopwood originally designed the Dominator engine in the 1940s a CAM SHAFT OIL BATH that was and I quote Mr Hopwoods letter to me ....'designed to retain as much oil as possible'.
Mr Hopwood, unlike so many so called Norton exspurtssover the decades and these days was fully aware that cams should be lubricated correctly especially during the engine start up period because without correct lubrication between the cam and follower galling takes place and once it has occured premature cam failure is assured. The Piper Cams tuning note book covers the subject.
With Mr Hopwoods oil bath the cam lobes pass through the RETAINED oil from the very first cam rotation giving CORRECT lubrication ....... Clearly the pratts later at Norton / AMC/ NVT knew nothing about Norton history or cam lubrication because with every new crank case pattern made the oil bath was removed a bit at a time till it no longer existed as in your crank cases.
Should youy decide to reinstall the oil bath the lip was originally designed to run within 1/8 - 3/32 of the flywheel rim.....Beware the thing does not foul the big end nuts.....
Looks to me from the pics as if the DS cam lobe is rather worn but that could simply be my olde eyes.
Mr Hele positively fed his Domirace cams as did Mr Geoff Monty on his Triumph twin engined Monadr race bikes (along with using a gear oil pump so that some oil still managed to reach the crank!!) I was told by a Gentleman working with Mr Hele on the Domirace project that the reason for the 6 start oil pump drive was simply a cherap bodge to ensure that some oil still reached the crank with the cetra supply being required to feed the cam.
Personally we never had a problem once we reinstalled the cam shaft oil bath.
All that effort and the use of a trapizoidal toothform AT10 belt.......Clearly you should should think about spending some time talking to a belt development Engineer regarding belt tooth form development over the decades because for power transmission the traqpizoidal tooth form was superceeded DECADES ago. But if it works for you.....
Mr Hopwood, unlike so many so called Norton exspurtssover the decades and these days was fully aware that cams should be lubricated correctly especially during the engine start up period because without correct lubrication between the cam and follower galling takes place and once it has occured premature cam failure is assured. The Piper Cams tuning note book covers the subject.
With Mr Hopwoods oil bath the cam lobes pass through the RETAINED oil from the very first cam rotation giving CORRECT lubrication ....... Clearly the pratts later at Norton / AMC/ NVT knew nothing about Norton history or cam lubrication because with every new crank case pattern made the oil bath was removed a bit at a time till it no longer existed as in your crank cases.
Should youy decide to reinstall the oil bath the lip was originally designed to run within 1/8 - 3/32 of the flywheel rim.....Beware the thing does not foul the big end nuts.....
Looks to me from the pics as if the DS cam lobe is rather worn but that could simply be my olde eyes.
Mr Hele positively fed his Domirace cams as did Mr Geoff Monty on his Triumph twin engined Monadr race bikes (along with using a gear oil pump so that some oil still managed to reach the crank!!) I was told by a Gentleman working with Mr Hele on the Domirace project that the reason for the 6 start oil pump drive was simply a cherap bodge to ensure that some oil still reached the crank with the cetra supply being required to feed the cam.
Personally we never had a problem once we reinstalled the cam shaft oil bath.
All that effort and the use of a trapizoidal toothform AT10 belt.......Clearly you should should think about spending some time talking to a belt development Engineer regarding belt tooth form development over the decades because for power transmission the traqpizoidal tooth form was superceeded DECADES ago. But if it works for you.....
- Joined
- Dec 10, 2008
- Messages
- 7,253
Deets55 said:
Yes, I am running a crank with a longer stroke, but the rod length has also been increased which reduces the side thrust.
It actually worked out to be a little less side thrust than original.
Actually side thrust helps keep the piston square in the bore. Most engines with short pistons use short rods which increases the side thrust. Jim
Deets55
VIP MEMBER
- Joined
- Oct 3, 2013
- Messages
- 1,510
Actually side thrust helps keep the piston square in the bore. Most engines with short pistons use short rods which increases the side thrust. Jim[/quote]
I was just thinking that the point where the piston changes direction the rock would be most pronounced, and that seems to be where you get a big drop during your leak down. Guess it's not that.
Maybe elliptical pistons might be on the agenda :shock:
Pete
I was just thinking that the point where the piston changes direction the rock would be most pronounced, and that seems to be where you get a big drop during your leak down. Guess it's not that.
Maybe elliptical pistons might be on the agenda :shock:
Pete
Deets55
VIP MEMBER
- Joined
- Oct 3, 2013
- Messages
- 1,510
Tommy,
I remember that. That's where I got the idea. I was joking with Jim, I can't image the work that it would take to make elliptical pistons and bores. If my memory serves me right I think it was the rings that were the most difficult to produce. I believe they even tried ceramic.
Pete
I remember that. That's where I got the idea. I was joking with Jim, I can't image the work that it would take to make elliptical pistons and bores. If my memory serves me right I think it was the rings that were the most difficult to produce. I believe they even tried ceramic.
Pete
Hi again Jim
A few questions for you if you have time to answer them.
Did you start using the Aluminium buttons after a circlip failure or just because you could ?
Did you use a piece of stock Aluminium to make the buttons and turn it to fit the piston ?
After the mess of my barrel from one circlip coming away I've become a bit paranoid about it happening again, how long have you been running the buttons?
Cheers
Mac.
A few questions for you if you have time to answer them.
Did you start using the Aluminium buttons after a circlip failure or just because you could ?
Did you use a piece of stock Aluminium to make the buttons and turn it to fit the piston ?
After the mess of my barrel from one circlip coming away I've become a bit paranoid about it happening again, how long have you been running the buttons?
Cheers
Mac.
- Joined
- Dec 10, 2008
- Messages
- 7,253
willy mac said:
I used buttons in race engines because I had seen the mess made when a circlip comes loose and spirolocks were not available in the size needed for a Norton.
Spring wire circlips work fine too but they require a special pin with a bevel on the end and the piston needs a groove designed for them.
I made aluminum buttons for the present engine using 2024-t6 bar stock. They must be a snug fit in the pin hole or they will get beat up.
I installed those buttons about 40,000 miles ago -mainly because the pistons I had on the shelf did not have any grooves for a circlip. Jim
Nater_Potater
VIP MEMBER
- Joined
- Apr 7, 2013
- Messages
- 1,342
Aluminum pin plugs are pretty common in airplane engines.
Something to keep in mind when installing circlips; with the acceleration forces being inline with the bores, make sure the circlip's openings are either straight up, or straight down (6 or 12 o'clock). If the opening lands along the sides (3 or 9 o'clock), there's the potential for acceleration forces to momentarily compress the clips, allowing them to flop out of their grooves. 'Learned the hard way with two-smokes when the clip protrudes into the transfer port...
Nathan
Something to keep in mind when installing circlips; with the acceleration forces being inline with the bores, make sure the circlip's openings are either straight up, or straight down (6 or 12 o'clock). If the opening lands along the sides (3 or 9 o'clock), there's the potential for acceleration forces to momentarily compress the clips, allowing them to flop out of their grooves. 'Learned the hard way with two-smokes when the clip protrudes into the transfer port...
Nathan
- Joined
- Dec 10, 2008
- Messages
- 7,253
Well I did a late night last night and put my motor back together since I have a 4500 mile trip planned for the next couple weeks.
I pulled out parts I had been stashing away for a blower motor build I have been thinking of for some time.
I had a nice looking but short set of forged Vertex pistons. They have nice thick tops so should be durable. they have a cup to reduce the compression for a blower.
I did not know how much clearance would be needed with these pistons as I had never used a piston with this skirt and taper.
I put a piston in one oven at 450 degrees and the barrels in another oven at 350 degrees and increased the clearance a few tenths at a time until the pistons would drop through the bore under there own weight. I ended up at .005" clearance cold and did a fine plateau hone finish.
I milled the top of the barrel enough to get a 9 to 1 compression ratio with .035 squish clearance.
Here is the pistons in the fresh barrels ready to set on the engine.
Here is the barrel set on 3 sockets waiting for the wrist pins and clips.
Pins and clips installed.
[video]https://www.youtube.com/watch?v=TEAkRz_Izrc[/video]
Now for the tricked out head. 3.5mm oversized intake valves and a full street port job. Grooved for silicone o-rings with copper rings around the bores. No head gasket. Inserts for 10mm plugs.
I took the bike out for 50 miles this morning. My Initial impression is a little less power under 4000 rpm but stronger than ever at 5000 rpm. About what I would expect with lower compression -but bigger valves.
The nice change is a 75+ degree drop in head temperature at 75mph. That should help my oil life.
I changed the oil and did a leakdown test this evening. It looks very good at around 4% leakdown. And no more crunchies. Now if they will give a reasonable life I will be happy. Jim
I pulled out parts I had been stashing away for a blower motor build I have been thinking of for some time.
I had a nice looking but short set of forged Vertex pistons. They have nice thick tops so should be durable. they have a cup to reduce the compression for a blower.
I did not know how much clearance would be needed with these pistons as I had never used a piston with this skirt and taper.
I put a piston in one oven at 450 degrees and the barrels in another oven at 350 degrees and increased the clearance a few tenths at a time until the pistons would drop through the bore under there own weight. I ended up at .005" clearance cold and did a fine plateau hone finish.
I milled the top of the barrel enough to get a 9 to 1 compression ratio with .035 squish clearance.
Here is the pistons in the fresh barrels ready to set on the engine.
Here is the barrel set on 3 sockets waiting for the wrist pins and clips.
Pins and clips installed.
[video]https://www.youtube.com/watch?v=TEAkRz_Izrc[/video]
Now for the tricked out head. 3.5mm oversized intake valves and a full street port job. Grooved for silicone o-rings with copper rings around the bores. No head gasket. Inserts for 10mm plugs.
I took the bike out for 50 miles this morning. My Initial impression is a little less power under 4000 rpm but stronger than ever at 5000 rpm. About what I would expect with lower compression -but bigger valves.
The nice change is a 75+ degree drop in head temperature at 75mph. That should help my oil life.
I changed the oil and did a leakdown test this evening. It looks very good at around 4% leakdown. And no more crunchies. Now if they will give a reasonable life I will be happy. Jim
- Status