Triumph Rat Motorcycle Forums banner

1 - 18 of 18 Posts

·
Registered
Joined
·
72 Posts
Discussion Starter #1
I have a 79 T140D with about 10,500 miles. I have no way of knowing if the odometer is genuine but, judging by the general condition of the bike, I think that it is likely that it is.
I have read widely of the ticking time bomb called a sludge trap, and fully intend to investigate mine - but just not now, maybe next winter.
I am a little paranoid as to the worse case scenario, which leads to my question:
Is there any way to assess the condition of the trap without splitting the cases ete etc.?
For example, my bike is idling at a fast tick of about 1100rpm, and the oil return line up at the top of the downtube, near the filler cap shows a steady stream, not just a glug,glug.
Is it too naive to associate a strong oil flow with with clear & open oilways?

Steve
 

·
Premium Member
Joined
·
4,721 Posts
The oil pump is positive displacement.It pumps a given amount of oil into the engine at a given rpm.If an oil passage is blocked,the relief valve opens and the oil dumps into the timing case,then flows down into the bottom of the crankcase.
The amount of oil that eventually makes it to the bottom of the crankcase never changes,whether it goes through the crank or out the relief valve.
All this oil gets pumped back by the return pump.

The highest mileage I've heard was 180,000 miles without opening the crankcases to clean the sludge trap.On the other hand,I've seen a bike 4 years old where you couldn't push a 1/8" drill through the sludge trap.
Its got a lot to do with what's in your oil.More frequent oil changes=less rubbish in the sludge trap.

At 10,500 miles,I wouldn't be too concerned.Just keep up the frequent oil changes,and a return-line filter helps too.
 

·
Registered
Joined
·
72 Posts
Discussion Starter #4
Well that gives me a bit of comfort - 180,000 sounds good, 30,000+ less so. Pete, well explained re the pump process. Yes, I am careful with oil changes and one of the first things I did was fit an external filter. You have put my mind at rest. I will get to it eventually, but not sweat too much before hand.

Steve
 

·
Registered
Joined
·
3,989 Posts
I think it was recommended here somewhere, that 10,000 miles was the service check-mark for the oil tube.
 

·
Registered
Joined
·
847 Posts
I hope not. My '59 has only done 10,000 miles since the cases were split and the sludge trap renewed. It has had 10 oil changes in that time, and I have no plan to dismantle the bottom end in my (remaining) lifetime.
Cheers,
Neil.
 

·
Premium Member
Joined
·
9,524 Posts
you need to bear in mind that the whole design's a bit old and in the 30's and 50's it was common for rebuilds to be done with alarming regularity as bearings didn't last and decoke's seemed to be really common.

my Tiger Cub instruction book from 1960 has hand written notes indicating decokes at about every 3k miles

10 k does seem a short life but I wouldn't be surprised if it applied to the earlier twins at all.
 

·
Registered
Joined
·
6,527 Posts
I'm no Triumph expert, but my humble opinion are the numbers being thrown out are not enough data on which to base a conclusion. I would say that the condition of the sludge trap is based on a few variables, that unless you owned the bike from new, you have no idea how they might have varied. Type of oil used is critical. If the PO's used cheap oil, non-detergent oil, etc., the chance of sludge building up is increased. If oil changes were regular and early versus infrequent and at extended intervals, this will play a major role. Lastly, how the engine was run needs to be considered. Did it spend it's life out on the open road at speed with plenty of cooling air or did it spend its life in the city, in stop and go traffic, idling, and with oil cooking engine temps?

So, my point is, unless you owned it from new or know the history with 100% confidence, you might as well flip a coin as go by the numbers mentioned here that were not accompanied by the variables that were in play as those numbers were developed.

I know we all like to get a level of comfort from the experiences of others. But I have to go back to a slogan my friend used to have emboidered on the sleeve of shirts he wore to power plants as a consulting engineer. "To measure is to know". Pretty much sums it up dontcha think? If you did not measure or inspect it yourself, it's just a rumor.
Again, just my humble opinion.
regards,
Rob
 

·
Registered
Joined
·
289 Posts
I have never heard of an engine self-destructing because the sludge trap blocks. So can it happen? Has anyone heard of it?

Probably not. The sludge trap uses centrifugal force to eject the heavier sludge to the sides of the trap, leaving a free oilway through the middle. But what happens when the sludge builds up to the point that the oil way through the trap is of the same dimensions as the oilways leading to and from the trap? The oil won't know the difference between the oilway and the sludge trap.

So, if this deduction is correct, there is no more chance of the sludge trap closing off the oil feed to the bottom end as there is of the oilways themselves closing it off.

Timebomb? Maybe not. Except that when the trap is 'full' it will no longer fulfill its funtion, so the oil will get dirtier quicker. So keep those oil changes up!
 

·
Registered
Joined
·
914 Posts
When I were a lad the only time people mentioned their sludge trap was when they had their crank reground. It was not considered a service item.

These days people have time and money on their hands so worry about things perhaps unnecessarily.

Then you get the old bikers tale of ..."and another thing have you checked your Xyz yet? If you don't it will surely bite you on a cold and dark night" ...

Clean you trap if you want too but best of all enjoy your bike.
 

·
Registered
Joined
·
6,527 Posts
Both Derry and Vince make valid points. Again, I'm a newb to Brit bikes and have no empirical data that would indicate that the traps plug or don't. My point was you cannot take two datapoints and formulate a conclusion.

Honda used a similar scheme on their early engines, but it was a separate component that could be removed relatively easily. I've taken a few of these apart, and if the outside of the bike was an indication of the care they got, they got little. The worst of the lot had a small build up of sludge on the ID of the trap, but nothing that would even come close to plugging up the system. Granted, these traps are much larger in diameter, maybe 1 inch for the small up to 1-3/4 for the largest. But then again, only about an inch or so deep.

The point that the two gents above make is valid because as the ID of the build up decreases, the inertia that would cause further build-up decreases. So there is probably little chance that it would build up to the point that it would shut off the flow. The force of the flow itself would be greater than any intertia at the center of the crank so any crud would simply continue on.

But, in the case of an engine that has sat for a long period, my concern would be that build up could break free for some reason once the engine was restarted and there is a good chance that a small chunk of build-up could block off what remained of the oil passage. I would agree that for a bike in continuous service, the chances of plugging are slim. But once an engine has sat for any period of time, as in many years, all bets are off. Once could argue that old deposits are probably more like concrete than oil sludge, but you never know. Again, just an opinion.
regards,
Rob
 

·
Registered
Joined
·
53 Posts
The never ending sludge trap Thread. Might as well dive right in. Do engines fail because of problems associated with the sludge trap. YES!
The failures are most often catastrophic leaving you looking for a new motor.
Here is the good news for you. Your bike is new enough that it probably never had a non-detergent single grade oil run in it. If it had frequent oil changes than the sludge trap probably does not have a great deal of sludge in it. The one I opened at 12,000 miles that had been run on a single grade oil didn't have a lot in it. I wanted to run a High detergent multi-grade and did not want to risk breaking loose the sludge.
The problems with sludge build up in older vehicles both cars and motorcycles pertains primarily to vehicles that were run on single grade non detergent oils. Wether it was a Harley, flathead ford, 39 Buick, or older Triumph the problem was similar. The newer oils would break up the sludge and all hell would break loose.
I would me more concerned that an oil line had solidified. If the oil was changed once a year with the mileage on the bike, it should be fine. Acids build up in engine oil. If old oil is left to sit in the engines these acids can cause considerable damage. Its why they recommend that you put new oil in your bike if you are going to put it into long term storage.
As always, get the best info you can and then do what you think is best. I probably would not pull the engine down. I have paid for this in the past but this doesn't seem likely candidate.
 

·
Registered
Joined
·
3,989 Posts
Mmm, maybe this will change the sceptics minds :)


Most of this stuff is solid carbon and metal, the sludgy bits are `pasty` carbon and metal... not much oil passing through there :eek:
But that`s not the whole story, after removing the oil tube there`s still muck in the crankshaft orifice.

 

·
Registered
Joined
·
289 Posts
Can sludge traps plug up solid?

YES.

As stated, resulting in catastrophic failure in most instances, serious overhaul issues in the remainder of the cases.

Yes, yes, yes, sludge traps can (and do) plug up solid.
Seems a pretty poor design, then. Fit the engine with a device that fills with crud but can't be serviced without stripping the motor, but if you don't service it, the motor blows up! :mad:
 
1 - 18 of 18 Posts
Top