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#392825 - 09/03/11 4:36 pm Freshly Rebuilt T120---Oil in left cylinder  
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dracko Offline
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Completely rebuilt this 1971 T120 engine from the sludge trap up. Rebuilt head with new guides/cut valves..etc..etc.

Followed the Healey article in Vintage Bike to ensure the rings seated. Especially since i'm using Hastings rings with the chrome top ring.

Been riding it for about a month. The bike starts first kick, pulls hard and runs pretty good..which is surprising considering the oil in the left cylinder.

Right side (#1) is beauty. No oil getting past rings and plug is nice tan brown color.

#2, not so much. I am steadily getting oil in the cylinder which is leaving a wet/black plug. Thought maybe the rings just needed time to seat, but its only getting worse.

Here are a couple pictures of #2 cylinder ports.

There is a small puddle of what looks like oil/gas in front of the intake valve. Not good.



Exhaust is very black/sooty/oily.



Bike has great oil pressure, installed Morgo pump.

Compression in each cylinder is 148 PSI.

Running 20w50, MAP oil filter kit installed. Drained the sump and got the normal amount of about 150ml.

I re-torqued after the first heat cycle and again after longer rides. Adjusted valves with each re-torque.
Just been riding around town so not a ton of miles racked up.

Also used the larger washers under the inner head bolts to prevent loosening/indents in the head.

The guy that built the head ensures me that the guides were properly fitted in the head and the valves guides clearance is spot on.

I'm starting to think I must've installed the rings wrong? or for some reason the the rings didn't seat on this side.

But i'm looking for suggestions from folks that have seen this before. Any advice appreciated.

Thanks
Dan

Last edited by dracko; 09/12/11 3:03 am.
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#392833 - 09/03/11 6:40 pm Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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Dan,

Looks to me like the inlet guide with the puddle of oil might be your problem ... not many ways that oil could get in there.

Could be that the inlet guide had some carbon on it when it was pushed out, and that scored the bore in the head. Otherwise it could be the guide does not have sufficient interference in the head ... either way, oil would seep past the guide.

There are various ways to repair the problem, but all require pulling off the head.

.. Gregg


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#392840 - 09/03/11 8:04 pm Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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Thanks for the info Gregg. If I've got 150 psi compression, does that rule out unseated or wrongly installed rings? Strange they would seat on one side and not the other.

I'm going to pull the head either this afternoon (if I can get some time in the garage) or tomorrow morning and take a closer look. Is a leaky guide something I'll need to also remove the springs to see? Any tell tale signs to look for on the head?

cheers.

#392870 - 09/04/11 12:01 am Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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I was told not to use 20/50 oil while breaking in the motor.
30 weight non detergent. Repeat, 30 weight non detergent.
I thought I would use the best 20/50 synthetic for my newly rebuilt engine. After 500 miles, I had the barrels off and getting a reboar and new pair of pistons. The rings never seated. Smoke! You have never seen such smoke!
If I had to do it over again, I wouldn't have torn the engine apart the second time. I would have drained the 20/50 out of it and run it hard with the 30w for a hundred miles and see if it didn't improve.


Please do not believe anything I write. I am a hack but I like to guess the right answers.
#392874 - 09/04/11 12:19 am Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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Hi Dracko,

20/50, but which 20/50?

Doubt that is your problem, but I thought I would bring it up.

Most likely gregg has it. Best way to get the valve guides out is too mill them and then push them into the combustion side. Else carbon can mess it up. Despite the guys assurances, I bet he messed it up.

Chrome ring seems good but, I remember Ricardo saying that a special additive is needed to get them to seat, in a reasonable time. He never mentioned what the additive was.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#392897 - 09/04/11 5:05 am Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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Thanks for the responses. As listed in the Healey article, I did run 30wt non detergent for a few weeks of riding around town- with 2 oil/filter changes in that span. I didn't pussy foot it either, good pulls through the rpm range, varying rpm, no idling. Then I switched to the 20w50 because that 30wt isn't good on long runs..doesn't maintain much viscosity when real hot. I also figured the rings were seated since the right side cylinder is running so clean.

Is there any way to tell whether i'm getting oil from the guides or from the rings?

Will a leakdown test tell me anything?

I was told I could fill the cylinder with air and use a bar/lever fork setup to get the springs off with the head on. I think i'm going to try this. Anybody trid using Loctite 567 under the guides with success?

thanks again

Last edited by dracko; 09/04/11 5:10 am.
#392909 - 09/04/11 9:00 am Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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If it is rings you would get smoke on acceleration but if it was guides you would get it on deceleration or a puff of smoke when you change gear.
dave

Last edited by dave jones; 09/04/11 9:20 am.
#392920 - 09/04/11 11:08 am Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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I'm with Gregg and Bob on this one....I had my guides replaced last year, but had the foresight to have the head soda blasted before they were extracted...this forum has saved my a$$ countlesss times...

I know Pete R has said that if the guide is still tight in the head, you can seal around the guide and lower spring collar with silicone sealant or Loctite 567.

Steve


'77 T140J
"Vintage Bike". What's in your garage?

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
#392924 - 09/04/11 12:43 pm Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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It's hard to imagine that oil staying in the port during an intake stroke.The engine would have been idling when it was shut off.There would be high cylinder vacuum and fuel/air still flowing into the cylinder at the end of intake stroke.

I think that oil got there after the valve closed.Either leakage around the valve-guide OD,or the intake port has an extra hole connecting it to an oil reservoir.I can't see any extra holes that shouldn't be there,but it might be worth investigating the thickness between the flange threads and the rockerbox interior.

If the engine was shut down on the prop stand,1/2 the oil in the rockerbox would gravitate toward the primary side intake port.

Leakage around the valve-guide OD seems to pull in a lot more oil than a worn guide does.There must be more oil around the lower spring collar than there is on the valve stem.

#392937 - 09/04/11 2:24 pm Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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Hey Pete, your idea to remove the spring with the head on worked like a charm. I poured some kerosene around the guide but not enough to reach the stem hole or pushrod tube, and it looks like it is seeping in around the guide slowly...probably faster when heated up.


Last edited by dracko; 09/04/11 4:29 pm.
#392983 - 09/04/11 5:47 pm Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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Originally Posted By: dracko
Hey Pete, your idea to remove the spring with the head on worked like a charm. I poured some kerosene around the guide but not enough to reach the stem hole or pushrod tube, and it looks like it is seeping in around the guide slowly...probably faster when heated up.



Looks like you proved where the oil is coming from ... better around the guide than a casting flaw!

If you think you can re-install the valve spring with the same technique you used to remove it, I would degrease the head and lower spring seat very carefully, and then reassemble with high temp silicone sealant between the two.

Let it cure thoroughly, and I'll bet that will stop the oil leakage into the port ... and then you can have a chat with your man about the work he did on the head.

.. Gregg


Spyder Integrated Technologies
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#392993 - 09/04/11 6:44 pm Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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Ya know what, that may not be the problem after all. At first I was getting traces of leakage on the clean paper towel i was using to spot leakage. But now I'm getting nothing coming through and the guide seems like a real tight fit in the head.




Last edited by dracko; 09/04/11 9:57 pm.
#393017 - 09/04/11 10:57 pm Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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I think this deserves a thorough test.Something unusual is happening somewhere.I'd even unscrew the port flange,to check for any leakage between the thread and the rocker box.
Seal off the pushrod tube,or dam up one side of the rocker box.Then flood the primary side spring seat and guide flange with kerosene.
Then just wait and see.Any leakage might be more noticable when the engine is running:the head would be hot,and there would be vacuum in the intake port.

#393052 - 09/05/11 2:36 am Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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Quote:
You're in denial. Off with the barrels and a re-hone and cast iron rings.


yeah you may be right, I have no beef with ordering some new rings and getting it honed again. Just don't want to go to that work if it isn't necessary. I find it strange that the rings would seat excellent in the right cylinder and not the left.

Plus, how would the intake port get full of oil if its getting past the rings? The valve should either be closed, or air getting sucked into the cylinder...not forcing it out into the port.

Does a leak down test prove anything?

Thanks again for the help with this.


Last edited by dracko; 09/05/11 2:37 am.
#393065 - 09/05/11 8:22 am Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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A Triumph does a certain amount of spitting back through the carb, etc. I wonder if with a cylinder full of oil whether it would collect in the intake?

Judging by the posts on this site about low mileage bikes it does sound like the rings have failed to seat on that cylinder. If this is the case then I would fit some good quality cast iron rings, as suggested by overandout.

The only other thing is whether there is oil being sucked into the cylinder from a bolt hole via a loose head gasket? Don't know if this is actually possible.

Dave

Dave

#393091 - 09/05/11 1:36 pm Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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I've had oil leaks in to the ports from the sleeved cylinder head bolt holes. The solution is to fit longer sleeves.
I've also broken into the valve spring well due to porting, the solution being either welding or plastic metal.

Stein Roger

#393098 - 09/05/11 3:14 pm Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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Drako:
Why did you remove the picture of the intake port?

The 1971, and later, heads are prone to leakage of oil down the 4 inside head bolts (studs in your case). Tom Sharp, and others, have made up head washers that include a seal. This prevents oil from draining down the head bolt (stud).

It is not uncommon or these heads to be fitted with sleeves where the port has broken into the head stud area. There is always the possibility of oil leaking down the stud and past the sleeve into the port. Remove the left intake head nut and washer and flood the area with kerosene. I think Stein is on to something!
John


#393099 - 09/05/11 3:15 pm Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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Originally Posted By: dracko
<SNIP>

Plus, how would the intake port get full of oil if its getting past the rings? The valve should either be closed, or air getting sucked into the cylinder...not forcing it out into the port.<SNIP>



Exactly. While you may well have rings that have not yet seated, that would not explain that massive puddle of oil in the inlet port.

Bear in mind also, that while the valve guide may *feel* 'tight' in the head, that does not mean you have a proper job ... a scored bore in the head for the valve guide would let oil through, especially when the head is hot. To test for leakage, it is best to do it with something thin, like kerosene as suggested above by PeteR.

... Gregg

Last edited by gREgg-K; 09/05/11 3:19 pm.

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#393129 - 09/05/11 7:46 pm Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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Quote:
Why did you remove the picture of the intake port?


Hey John, I looked at an old T120 head I had on the shelf and it also had the headbolt sleeve coming through into the intake port, so I figured it was the norm. There was signs of oil on the headbolts, but after filling the headbolt hole with kerosene, there was no leakage there. I also left the guide submerged with kerosene over night and there was no leakage.

I would like to get my hands on some of those washers you mentioned with the oil seals though.

Dave thats interesting you mention the engine spitting back through the carb, the bike was doing that the odd time on the left side only. It only happened when kicking it to start and then ran fine after it fired up. I figured it was due to the plug being covered in oil. It may have been spitting oil back into the port each time...but wouldn't it just get sucked back into the cylinder once the engine fires? Man. I'm confused. lol

I did always put my finger over the return hole in the oil tank to force oil to the rockers on startup. Is there a chance I was flooding the rocker boxes with too much oil ?

I find it strange that the rings would bed in one cylinder and not the other, but to eliminate the possibility of this being a problem, I'll order up some hastings cast iron rings and get ready to start this process over again in the spring.


Last edited by dracko; 09/05/11 7:53 pm.
#393133 - 09/05/11 8:07 pm Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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Originally Posted By: dracko
I did always put my finger over the return hole in the oil tank to force oil to the rockers on startup. Is there a chance I was flooding the rocker boxes with too much oil ?




Hi Dracko,

I would think yes it would. If the picture is of the time just after you did that, maybe yes.

You did mention that you replaced the too small washers with larger ones, and that is why I did not mention what John did. But you did not say whether or not there were depressions in the head from the too small ones. So perhaps you did not catch the problem. There could also be a small hair line crack which opens up more with heat and vibration.

So, other things to take into consideration to diagnose the problem. Did it smoke out the exhaust pipes? On Acceleration or deceleration? Smoke only for awhile after start up, ) indicates the head bolt problem), or even after long warm up?

Also I do not see you mentioning what brand of 20/40 weight oil. Castrol GTX will find it way into cylinder no matter what. I expect most auto oils will do the same, rated what SL SM? Too modern. Too many anti wear additives. They are meant for modern autos with very tight tolerances. Not our bikes.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#393260 - 09/06/11 5:53 pm Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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Quote:
Chrome ring seems good but, I remember Ricardo saying that a special additive is needed to get them to seat, in a reasonable time. He never mentioned what the additive was


Hey btour. I'm on the fence about pulling the head and jugs off and taking it in for rebore/new cast iron rings...or trying to work this out and ride it for the remaining month of summer. Where could I get more info on this additive?

After running non detergent 30wt for a few weeks, I switched to 20w50 motorcycle oil. It was Suzuki brand, non synthetic. I don't know the rating but I can check. I figured the effects of running 30wt oil had already taken place and it would be alright to switch to something better for the engine.

I pulled the 2 headbolts on the left side and there are no indentations under them, but they did each have a coat of oil on them.

I may try sticking some viton orings under the washer if I bevel the inner edge of the washers...like mentioned in a thread on this site. Would it be dumb to just lay a thin bead of hondabond around the bolts and install them? Don't really see that silicone getting out of there from under the washer.

It smoked on start up for a while, but prior to pulling the rockers it was smoking for longer...all that oil in the intake port probably.

#393266 - 09/06/11 6:49 pm Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
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btour Online content
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Hi Dracko,

Originally Posted By: dracko
Where could I get more info on this additive?


I really wish I knew. Ricardo never mentioned what it was. I have been hoping someone on this forum would know. But nothing yet.

Perhaps it is Bon Ami? Borax? Run in without running the engine, but cranking it somehow mechanically? I am just speculating.

Originally Posted By: dracko
I pulled the 2 headbolts on the left side and there are no indentations under them, but they did each have a coat of oil on them. .... It smoked on start up for a while, but prior to pulling the rockers it was smoking for longer...all that oil in the intake port probably.


Sounds like the inner head bolt situation is part of the problem. It may also be valve guide, and your flooding of the rocker boxes. All contributing a bit.

About the head bolt problem: According to Jaye Strait, in his experience, some bikes leak, and some do not. He has not figured out what makes the difference yet. I certainly do not know. Speculation: Perhaps it is how square the bolts holes are tapped to the cylinder and head? Something like that making a slight difference from one to other in the manufacturing.

Jaye says, sometimes the oil finds it way to the outside and sometimes the inside. Sometimes both.

Originally Posted By: dracko
I may try sticking some viton orings under the washer if I bevel the inner edge of the washers...like mentioned in a thread on this site. Would it be dumb to just lay a thin bead of hondabond around the bolts and install them? Don't really see that silicone getting out of there from under the washer.


I would think either would work. John uses the o-ring. Jaye uses some kinda of high temperature silicone. The o-ring may take more talent to install to keep it from tearing or ripping or squashing out of shape. The goop may take more effort to use the correct amount and not to tighten all the way, at first until it sets up, so it all squeezes out. Pick your poison.

But the hot setup would be to get the special washers that someone, (Tim?) makes. The ID of those is also closer to OD of the head bolt: I think I remember reading that.

Originally Posted By: dracko
After running non detergent 30wt for a few weeks, I switched to 20w50 motorcycle oil. It was Suzuki brand, non synthetic. I don't know the rating but I can check. I figured the effects of running 30wt oil had already taken place and it would be alright to switch to something better for the engine.


Yes and that is what to do. Please note that some people make the distinction between seating and sealing with regard to the rings. Thus they may seat in 50 miles but not seal for a few thousand more. The sealing may be more a function of the oil ring. So having the proper oil ring is important also for sealing, but I do not think that this is first source of a problem in your case.

See the seating of the compression rings is helped by having the proper metal for rings, grey iron, and proper grit honing, (of course proper clearances and ring gaps too), and then properly ridden the compression gets in between the ring and piston and forces it outwards against the honed cylinder wall and that wears the softer metal to fit the cylinder with all its imperfections.

You have chromed rings so, the wear in process may take longer, but the idea is the chrome will also prevent wear in the further life of the engine. Which is the idea of the thing.

The oil ring presents a different situation. There the compression does not force the ring outwards against cylinder wall to make the ring "wipe" the oil. In this case it is the tensile strength of the metal the ring is made of and to some extent the thickness of the ring itself as the pressure of the ring outward is determined to some extent as a factor of its size, like in pressure per surface area of contact.

The original hepolite oil rings were very good. There is some amount of effort being made to have comparable oil rings made.

So this is where the additive package in the oil comes in. Modern auto oils will tend to creep right past and remain in place.

You have motorcycle oil in your bike, so that is good. Check the rating. I try to use a rating closest to the original SG, so I use Spectro HD 20/50 rated SG. The rating refers to the additive package in the oil.

Originally Posted By: dracko
I'm on the fence about pulling the head and jugs off and taking it in for rebore/new cast iron rings...or trying to work this out and ride it for the remaining month of summer.


If it were me, I would opt for the latter. After having done something to try and fix the inner head bolt problem, if it exists. I would try to save the money, time and work if possible. I would also be curious and want to determine the source of the problem by addressing one thing at a time. The head bolt problem being the easiest, it would be first.

You might want to add a bit of leaded real gas, (racing fuel), just to guard against detonation which might result from having a bit of oil in the cylinder at start up.

Originally Posted By: dracko


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#393275 - 09/06/11 7:34 pm Re: Freshly Rebuilt T120---Oil in left cylinder [Re: btour]  
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Hi bt,

you mentioned Bon Ami to seat rings ( i think) and it reminded me of a problem with early chevy v-8's.

Here's an excerpt from an inquiry:

Quote:
This was the GM approved break-in by the dealers back in 1955 for the new v8. They had nigh nickel content in the first engine blocks (super hard) and a chrome vanadium piston ring and too fine a cross hatch hone pattern that was not productive in achieving a proper ring seal. The cure was to run the engines at a fast idle---1500 to 1800 or so and let the engine inhale (with the oil bath air cleaner off) the powder off of a tablespoonfull or so of the powder thru the two barrel carb into the engine. Took about 30 minutes or so. Then run the car hard on a test drive, warm the oil good and change it. Return to customer. Seems Chevy did not want their new high reving v-8 to get a bad rep from the start and had thrown a goodly amount of heavy duty parts into the engines from the get-go.....forged cranks, rods, chrome-vanadium rings, oil filters, good high tensile valve springs, etc. on their Ford beater. At 265 cu.in. and 165 horsepower rating, it was a world beater....and the rest is history. And imagine, a car factory going to all that trouble to achieve customer satisfaction on new car introduction. My how times have changed. Now they throw them together before introduction, and only fix anything that they can't get away with.

Last edited by Brien Morrissey; 09/06/11 7:38 pm. Reason: ford vs chevy

1978 Bonneville T140V PX
#393416 - 09/07/11 4:53 pm Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
Joined: Jan 2009
Posts: 117
dracko Offline
BritBike Forum member
dracko  Offline
BritBike Forum member

Joined: Jan 2009
Posts: 117
Canada
Thanks for that info Brien. I sealed up the head bolts last night and plan to seal up the guides, silicone the collars tonight. Then if i'm still getting a bunch of oil I may try the bon ami in that cylinder.

cheers.

#393437 - 09/07/11 6:19 pm Re: Freshly Rebuilt T120---Oil in left cylinder [Re: dracko]  
Joined: Jul 2009
Posts: 3,549
Pete R - R.I.P. Offline
In Remembrance
Pete R - R.I.P.  Offline
In Remembrance

Joined: Jul 2009
Posts: 3,549
Vic. Australia
If you use the Bon Ami,it should be the 1886 formula (yellow container),not the newer cleanser (metallic-looking gold container).
I've never tried it in the intake,but I've seen claims that sodium bicarbonate works too.

I'd always use Bon Ami or something equivalent to lap rings in when I build an engine,but I wash it off before assembly.
I know people who don't wash it off,just wipe the excess out of the bores,and put the head on.They still get good results.They change the oil within about 20 minutes after a rebuild.

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