Classic British SparesKlempf British PartsBaxter CycleBritBike Sponsor SteadfastCyclesSRM EngineeringLucas Classic MotorcycleHepolite PistonsIndustrial tec supply

Upgrade your membership to: Premium Membership | Gold Membership | Life Membership | Vendor Membership | Site Sponsor Membership
Welcome to BritBike Forum!
Britbike forum logo
Member Spotlight
Danam
Danam
San Francisco
Posts: 185
Joined: July 2019
ShoutChat
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Previous Thread
Next Thread
Print Thread
Page 1 of 2 1 2
#846151 04/15/21 1:56 am
Joined: Aug 2019
Posts: 57
T
tommy Offline OP
Britbike forum member
OP Offline
Britbike forum member
T
Joined: Aug 2019
Posts: 57
i recently been having issues with my triumph these last few weeks. i decided to take the heads off and noticed oil being left on the cylinder walls.

Took the cylinder off any found some interesting things

Looks as if i need to tear the motor apart and replace the lifters and cams

Whats your thoughts?

The pistons are scored by the rings but overall they seam reusable, only issue is the wrist pin is stubborn to get through the piston but the wrist pin bushings look great and are in spec

IMG_1999.jpg IMG_1996 2.jpg IMG_2001.jpg IMG_2002.jpg IMG_2003.jpg
Last edited by tommy; 04/15/21 1:59 am.
Support Your #1 BritBike Forum!

Check out British motorcycles for sale: British Motorcycles on e-Bay UK, British motorcycles on e-Bay North America
Joined: Aug 2001
Posts: 5,613
Likes: 71
M
Britbike forum member
Offline
Britbike forum member
M
Joined: Aug 2001
Posts: 5,613
Likes: 71
I hope some of the real engine forensics experts chime in, but in the meantime:

1. It looks to me like the piston got very hot. I think the other one too, but it's a little hard to see in the photo.

2. The normal cam wear I've seen is usually an even stripe across the top of the lobe. Your cam wear is uneven, and in the last photo, severely rough. I don't know what would cause this; perhaps oil starvation?

It's not unusual for the wrist pin to be tight in the piston. Many times I've had to heat the pistons before tapping out the pins. (FWIW, laying a clothes iron across the piston crowns is a convenient way to heat the pistons.)


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Joined: Jan 2014
Posts: 1,493
Likes: 136
N
Britbike forum member
Offline
Britbike forum member
N
Joined: Jan 2014
Posts: 1,493
Likes: 136
Looks like the rings never bedded in.
They look like they've nearly nipped up.
The cam looks stuffed probable dirt or lack of oil.

1 member likes this: Allan G
Joined: Aug 2019
Posts: 57
T
tommy Offline OP
Britbike forum member
OP Offline
Britbike forum member
T
Joined: Aug 2019
Posts: 57
Can used cams that are in good condition be used with new lifters. I know the other way right is not valid

Joined: May 2013
Posts: 8,010
Likes: 148
A
Britbike forum member
Offline
Britbike forum member
A
Joined: May 2013
Posts: 8,010
Likes: 148
Looks like your either using Duchams or Comma Classic oil?


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Joined: Aug 2015
Posts: 1,765
Likes: 39
A
Britbike forum member
Offline
Britbike forum member
A
Joined: Aug 2015
Posts: 1,765
Likes: 39
The cams look to have been hot


BSA B31 500 "Stargazer"
Greeves 200 "Blue Meanie"
Greeves 350
Greeves 360
Suzuki GSX1100 EFE "Sorcerers Apprentice"
GM500 sprint/LSR bike "Deofol"
Jawa 500 "Llareggub"
Aprilia RSV Mille "Lo Stregone"
'35 & '36 OK Supreme
Kawasaki ZZR1400 "Kuro no senshi"
Joined: Aug 2019
Posts: 57
T
tommy Offline OP
Britbike forum member
OP Offline
Britbike forum member
T
Joined: Aug 2019
Posts: 57
Penn grade sae40

Joined: Aug 2019
Posts: 57
T
tommy Offline OP
Britbike forum member
OP Offline
Britbike forum member
T
Joined: Aug 2019
Posts: 57
What could cause the cams to get hot. Oil pressure was good as far as I can tell? Steady oil coming out of the oil tank return line.

Joined: Feb 2005
Posts: 877
Likes: 10
M
Britbike forum member
Offline
Britbike forum member
M
Joined: Feb 2005
Posts: 877
Likes: 10
Originally Posted by tommy
Can used cams that are in good condition be used with new lifters. I know the other way right is not valid

Yes, good used cams with reground or new lifters have been used many times.

You said this engine is a '68 T120 with about 300 miles on a new rebuild, the cams appear to be new from looking at the unmarred areas, are they stock or a performance grind? Did you rebuild the engine? If so did you use new or reground lifters, did you use a dedicated cam break-in lubricant, do you know the installed valve spring pressures, upon initial start up did you maintain rpm at or above 2000rpm on a short ride (10 minutes or more) to maintain cam lubrication for proper cam break-in? Just speculating here, not knowing your break-in regime, it sounds like you may have spent more time fiddling with the carbs then would have been conducive to a good break-in. Perhaps to much time running at a stand still, I don't know from your post but just guessing.

Even though the compression was equal, the side with the oiling issues could indicate artificially high due to the oil helping seal the rings, it also sounds like the blow by on the bore would indicate rings not seated yet. Did you set the ring end gaps? Were the cylinders bored and honed by someone experienced with old British iron and grey iron rings? Can't speculate on the pistons since you didn't show us any thrust surface pictures and I don't know what you mean by pistons being scored by the rings, some of the vertical scratches can be caused by inadequate bore cleaning before assembly. Did you change the oil after the first 50-100 miles and retorque head and cylinder and adjust valves?

Sorry, more questions than answers huh? Starting off with a rebuilt engine and unknown carbs and jetting is a gamble since you can't spend the crucial early moments of the engines life breaking it in properly. This is something I've been considering in regards to the performance engine I'm trying to build. I may just do the break-in with a stock single carb head and an AMAL Concentric with known jetting (slightly enriched) requirements for a TR7, this way I can concentrate on the break-in, your case makes me think this would be the way to go for me.

It would appear you're running 9-1 cr pistons by the height of the dome. If you're riding style is more the chopper style chugging around, you may be better served by fitting lower comp., lower dome pistons especially considering our modern fuels.

Just stuff to think about...Mark R.

Joined: Oct 2012
Posts: 5,768
Likes: 126
knuckle head
Offline
knuckle head
Joined: Oct 2012
Posts: 5,768
Likes: 126
I agree with Nick, the discoloration below the top ring is blowby.. Penn Grade contains a good level of ZDDP...


79 T140D, 96 900M Ducati ,61 A10 .On a bike you can out run the demons.."I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
Joined: Aug 2019
Posts: 57
T
tommy Offline OP
Britbike forum member
OP Offline
Britbike forum member
T
Joined: Aug 2019
Posts: 57
Thanks for the replies. I’m thinking I messed up on the assembly when I reused the tappets without resurfacing them. Also my heads need new springs. So off they go to get head work and I was able to buy some new cams for the bike. As for the lifters I’m sending them out to get reground. I’m gonna dissemble the motor and make sure the crank and rods are ok.

AB670ECF-0342-4C55-884C-98F34E98727E.jpeg
Joined: Feb 2019
Posts: 475
Likes: 189
S
Britbike forum member
Offline
Britbike forum member
S
Joined: Feb 2019
Posts: 475
Likes: 189
Those light colored scratches on the ring lands looks like some sort of abrasive is getting into your top end. Running without air filters can do that. Also, bead blasted parts that weren't cleaned well enough, carbs maybe, could do it too. Post some pics of the rear thrust faces and someone here can give you more input.

That galling on your cams probably happened in the first 20 minutes of running. As Markster mentioned, you must get the bike out and riding quickly with a minimum of idling. This is to break in the cams and begin to seat the rings. Cams because they get a good bit of their oiling from splash, rings because cylinder pressure pushes the ring face tighter against the bore than the natural springiness of the ring.

Idling a fresh motor for a half hour or more and messing with adjustments in the driveway is a recipe for engine problems.

Joined: Aug 2019
Posts: 57
T
tommy Offline OP
Britbike forum member
OP Offline
Britbike forum member
T
Joined: Aug 2019
Posts: 57
Pistons

A4A798F8-62ED-4F90-A108-A159875AF9C1.jpeg
Joined: Aug 2019
Posts: 57
T
tommy Offline OP
Britbike forum member
OP Offline
Britbike forum member
T
Joined: Aug 2019
Posts: 57
More pics

4891727D-737F-49C8-96CA-271FC3FE0B6B.jpeg C58FAC21-FE17-4CBA-AC64-70F85E612A46.jpeg 30EFA2F8-B874-4476-8CE9-44DDF1FDBE01.jpeg
Last edited by tommy; 04/17/21 1:33 am.
Joined: May 2013
Posts: 8,010
Likes: 148
A
Britbike forum member
Offline
Britbike forum member
A
Joined: May 2013
Posts: 8,010
Likes: 148
Originally Posted by tommy
What could cause the cams to get hot. Oil pressure was good as far as I can tell? Steady oil coming out of the oil tank return line.

Whilst penn is a good oil, a straight 40w will have poor flow characteristics when cold, so you will have great pressure but most will be flowing back to the tank. A nice 20-50 will still be quite viscous when cold but not as much as the 40, so there will be a better flow of oil to the journals when cold.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Joined: Feb 2019
Posts: 475
Likes: 189
S
Britbike forum member
Offline
Britbike forum member
S
Joined: Feb 2019
Posts: 475
Likes: 189
Thanks for posting the piston skirt pics.

You have at least two issues. First is the scratches from some sort of debris. Those scratches are visible at the bottom of the skirt too. That makes me think that abrasive came from the crankcase side as well. Were the cases abrasive blasted? If so, how clean were they before assembly? Blast residue can get into the tiniest places only to emerge with the heat and vibration of a running engine.

Second, there are some small darkened marks , vertical lines, under the oil ring groove. Those are classic seized piston markings. They are light so the piston could probably be re used but those type of markings are mostly always heat related. This could be from incorrect ignition timing, lean carburetor jetting, running it too hard for a new engine, too tight piston clearance and so on.

What do the cylinder bores look like?

Joined: Aug 2019
Posts: 57
T
tommy Offline OP
Britbike forum member
OP Offline
Britbike forum member
T
Joined: Aug 2019
Posts: 57
The cylinder bores look great. No real marking or any wear patterns from what I can tell. I’ll post a pic later. They do look glazed though. The cylinder surface is glossy

Also the cases were never blasted. Just cleaned with brake cleaner and soap and water. Could be from the cylinder head, those were bead blasted

Joined: Aug 2001
Posts: 5,766
Likes: 148
G
Britbike forum member
Offline
Britbike forum member
G
Joined: Aug 2001
Posts: 5,766
Likes: 148
These pistons look they have seized twice, the first time around the scores were sanded off with horizontal strokes.
Check piston to bore clearance, may be too tight. if thats OK, it may be the ring end gaps were too tight or they never seated properly,.
The scratches are nasty particularly the scratches between the rings, suggesting poorly cleaned parts on assembly.
its nothing to do with straight 40 oil, my bike ran for years on that with zero piston problems.

Last edited by gavin eisler; 04/17/21 9:38 pm.

71 Devimead, John Hill, John Holmes A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Joined: Aug 2019
Posts: 57
T
tommy Offline OP
Britbike forum member
OP Offline
Britbike forum member
T
Joined: Aug 2019
Posts: 57
Guess I’m doing bottom end now.

What’s the best solution to making sure when I reassemble that this motor is spotless. And what do you guys recommend for assembly lube?

21E15313-269D-4CBE-AEA4-EA6CE350A7C2.jpeg 524C8109-8A0C-439E-B05E-D012965B939A.jpeg D7F429D4-15A5-4010-A624-038D351F3B09.jpeg 1146A4F2-F3D0-4A75-87E1-07AC17441DCF.jpeg 80CA3EDA-3DD5-4A7A-9B9F-87AFE6DAC336.jpeg
Joined: May 2013
Posts: 8,010
Likes: 148
A
Britbike forum member
Offline
Britbike forum member
A
Joined: May 2013
Posts: 8,010
Likes: 148
Originally Posted by gavin eisler
These pistons look they have seized twice, the first time around the scores were sanded off with horizontal strokes.
Check piston to bore clearance, may be too tight. if thats OK, it may be the ring end gaps were too tight or they never seated properly,.
The scratches are nasty particularly the scratches between the rings, suggesting poorly cleaned parts on assembly.
its nothing to do with straight 40 oil, my bike ran for years on that with zero piston problems.

I didn’t say the oil had anything to do with the pistons Gavin 🙄. But I agree with your statement. Those pistons have been in twice before. But my point is still valid, 20-50 will provide better oil flow and protection on a cold engine and better pressure when the engine is up to temperature. The tight areas, like big ends, cams etc look like they would have benefitted with a better oil flow at start up.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Joined: Dec 2004
Posts: 11,220
Likes: 131
Britbike forum member
Offline
Britbike forum member
Joined: Dec 2004
Posts: 11,220
Likes: 131
Shell bearings show they have been touching the journals and the crank journals are the same. You need to polish up the journals and fit new shells. There has either not enough oil getting to the journals or the oil is low quality, you need to use plastigage to check the shell bearing/journal clearance is correct and fit an oil gauge temporarily to check for good oil pressure. You seem to have mixed up tappets, one end has an inlet and an exhaust tappet fitted, the ones with holes are the exhaust ones. You also need to check the tappet oil feed is set up correctly for the exhaust tappets, Triumph changed the configuration over the years in an attempt to fix premature exhaust cam failure, the end cure of nitrated cams was so good they later dropped the exhaust tappet oil feed completely.

Joined: Feb 2005
Posts: 877
Likes: 10
M
Britbike forum member
Offline
Britbike forum member
M
Joined: Feb 2005
Posts: 877
Likes: 10
Tommy, to me it looks like it was a dirty rebuild...followed by improper break-in while trying to sort unknown carbs and settings. Not trying to bust your chops if it was your rebuild but saying it appears that dirt/abrasives caused your big end bearing & journal wear, your drive side main bearing also appears to be damaged from it's worn appearance (probably timing side also), pistons would appear to have had poor ring seal (improper bore prep and/or break-in?) resulting in pistons overheating and 'cooking on' of oil bypassed by poor rings seal. Can't comment on cylinder bores from pictures but from the rest of engines appearance one might speculate it needs some attention. What color or appearance do the rod small ends have? Wrist pins?

Don't know your abilities Tommy but from all indications I would be completely tearing this engine down and starting over, from the sludge trap out. I would also suggest flushing oil tank and lines. I'd check oil pump for wear/scoring from dirt also, I can't tell from pictures but it doesn't appear that you had oil pressure related issues. I also don't know if the main bearings were new and of correct clearance to start with but the one I see doesn't look good.

I have seen worse pistons reused with new rings and correct hone job with no issues. I can't emphasize how important a proper break-in procedure is for ring seal, compression, oil consumption. The rings transmit the heat out of the piston dome to the cylinder wall and until they seat the piston will run hot and expand more than when the rings seat, no high rpm steady state (throttle) running during break-in. I have a friend who decided a fast break-in run down the freeway would be good for a fresh rebuild on a '66 TR6, all stock except for cam. Engine experienced a 'soft' seizure and didn't immediately lock up but scored both pistons. Live and learn. Mark R.

Joined: Aug 2019
Posts: 57
T
tommy Offline OP
Britbike forum member
OP Offline
Britbike forum member
T
Joined: Aug 2019
Posts: 57
Hey Mark the small ends don’t look bad at all from what I can tell. I’ll post a picture of it. Also I measured the cylinder to piston Clearance they’re both at 0.0048

Joined: Oct 2012
Posts: 5,768
Likes: 126
knuckle head
Offline
knuckle head
Joined: Oct 2012
Posts: 5,768
Likes: 126
I have used pistons looking like that with new rings in decent deglazed bores with no problems..This was for a bike used maybe a 1000 miles a year...It all depends on how the bike will used, other guys like to spend your money grin. Do pay close attention to the bottom end as mentioned...


79 T140D, 96 900M Ducati ,61 A10 .On a bike you can out run the demons.."I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
Joined: Aug 2019
Posts: 57
T
tommy Offline OP
Britbike forum member
OP Offline
Britbike forum member
T
Joined: Aug 2019
Posts: 57
Small ends

C5F59A6C-870E-46E7-A7E7-75A5306E2F55.jpeg 459CD3FF-EE22-4C6E-AE46-09CCC14A6647.jpeg
Page 1 of 2 1 2

Moderated by  Jon W. Whitley 

Link Copied to Clipboard
Job CycleBritish Cycle SupplyMorries PlaceKlempf British PartsPodtronicVintage MagazineBSA Unit SinglesBritBike SponsorBritish Tools & FastenersBritBike SponsorBritBike Sponsor






© 1996-2021 britbike.com
Powered by UBB.threads™ PHP Forum Software 7.7.5