B25 carrillo

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vetterlatethanever
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B25 carrillo

Post by vetterlatethanever »

Not sure if its a problem or just coincidence.
But I have seen at least 4 separate Carrillo B25 rods for sale second hand, that had all spun there shells and wrecked the crank pin.
As I am thinking of buying one new is this a problem with the B25 rod?
what shells do they use, original bsa or carrillos own shells?
maybe im just being paranoid?
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Re: B25 carrillo

Post by koncretekid »

I'm using one of those Carrillo rods in my B25/TR25 land speed bike, but no long term experience. Hard to see how the rod could cause the failure. I Plastigauged mine with new inserts and found .001" clearance, which I guess is minimal but OK. Read E & V Engineering advice for the B25 oiling system, as it is reported that the crankshaft bolted on weights can leak oil out the sludge trap joint reducing overall oil pressure to the rod bearing.

I wasn't aware that Carrillo made their own inserts.

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Re: B25 carrillo

Post by kommando »

Never fit BSA NOS shells, they are whitemetal and next to useless. Shells are installed with an oversize length of a few thou which is called crush height, as the con rod is torqued up the shell is forced into matching the shape of the much thicker rod housing and this then grips the shell and stops it from spinning. If the shell seizes on the rod it breaks this grip and spins, the notch does nothing in this process, it's only there for location purposes not to stop the shell spinning.

Image

The best B25 shells are the Triumph Unit twin shells made from Al/Sn with a G inside a square stamped on the back, they will be missing the oil hole but I have my doubts as whether this is really needed, I run without. If you want more oil to go upwards to replace this oil hole feed then put a very shallow but wide groove in the upper part of the big end on the sides. This will direct some of the oil exiting the shell upwards. If you want you can drill the hole but put a wide chamfer on top and bottom.
Last edited by kommando on Thu Nov 15, 2018 7:48 pm, edited 1 time in total.
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Re: B25 carrillo

Post by Jeff K »

kommando
Why did Triumph only use the oil hole on one side. The first time that I saw this I thought that it was a mistake, but I have seen several more T100's with the oil hole only on one rod??
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Re: B25 carrillo

Post by kommando »

Never seen a direct quote form one of the original engine designers as to why, plenty of guesses from later interested parties. The one I think is the reason, is that it promotes oil flow on the driveside con rod so creating the right conditions in both bearings to maintain the oil film, this fits the evidence and also theory.

The pressure in the oil system detected by an oil pressure is not the pressure in the critical oil film, the pressure in the oil system is just telling you there is back pressure from oil being pushed towards the bearings and the correct clearances and flows are creating the back pressure. The bearing is looking for a flow of oil at the right temp , flow and viscosity so that an oil film is created and maintained within the gap between the bearing and journal and at a good pressure, this pressure inside the oil film is an order of magnitude above that given by an oil pressure gauge.

When you look at a Brit twin the oil typically goes to the timing side rod first where some is lost out of the bearing and then takes a longer route to the drive side, The flow is reduced by the time it gets to the driveside, by having a hole in the bearing you increase the flow and gain more oil as the timing side will less advantaged.

If you look at a lot of the twin threads on when a rebuild is due then you will see more mentions of the driveside rings being worn out sooner than the timing side etc, shells are typically more worn on the driveside too.

If they had had access to the bearing/crank modelling software introduced in the 80's then this hole could have been optimised to give equal flows, as it is they must have made a guess which alleviated the issue but did not completely cure it.
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Re: B25 carrillo

Post by matt49g »

Kommando,
Thank you for a very logical answer to a question that I've wondered about for a long time. Just having one drilled rod on a twin makes more sense now.

As for the original B25 Carrillo rod/bearing question, spun bearing shells is in no way the fault of Carrillo, or any other aftermarket, rods. The early B25's had a alloy oil pump and a spring and ball relief valve, both of which could give problems. A forum member called "Lathejack" has several posts that discuss the problem in detail. I have worked on a couple of B25's that had Carrillo rods installed 30 or more years ago, and the same rod is still being used. The bikes had been parked for twenty or more years, so it wasn't continuous use, but still an impressive service life.

I have encountered two spun bearings in B-25's using Carrillo rods, however both times (not the same bike) the failure was due to low oil level, not mechanical reasons. If everything else is correct, two other reasons for spun bearings could be damaged crankshaft end and/or seal or failure to drill the crankpin oil hole. I'm not getting into types of oil or bearing shells because unless the oil is getting to where it's supposed to go, both are moot.
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Re: B25 carrillo

Post by Jeff K »

Kommando
Great answer on the T100 rods and as they say. Now I know. Years ago I used to be able to pick up B25 and TR25W all day long for $50.00, that probably explains why I still have well over a dozen of them. The three biggest reasons for them being parked was.
1. Spun main bearing.
2. Flogged to dead trying to compete with 2 cycles by young drivers.
3. Missing second gear.
#1 - A old Triumph shop mechanic told me decades ago that the old bikes did not have a oil filter and only used non detergent oil. Detergent oil keeps the gunk suspended so it can be filtered out. Non detergent allows it to settle on the bottom like in a lawn mower. The problem that he said was here in Michigan the bikes are parked all winter so gunk does settle to the bottom while setting for months. And then when some one changes the oil and uses the more common detergent oil. The detergent oil does it's job and picks up all of the gunk from the bottom and then suspends it in the oil. Problem is there is no filter to remove it so the oil becomes abrasive and the soft parts are the first to go.
#2- Teenagers trying to keep up with the much more powerful 2 cycle and beating on the poor old BSA's. I grew up next to a old abandon golf course that was for many year the best place to ride dirt bikes. And the kids on the TR25W would strip them down, add huge rear sprockets, etc while trying to keep up with the K*waski's, S*zuki's and Y*amaha's of the era. They beat them to death.
#3 - This might have just been a local thing. But a lot of the guys racing the B50 in local Motocross did not use the clutch at the start and would instead stomp the bike into 2nd gear while cranking the throttle wide open when the start flag would drop. The end results was they were always looking for 2nd gear sets. Decades ago I got the last 2nd gear set that MAPP had to sell and they also told me the same story and they added that sadly the B50 gears were harder then the early B25, so swapping gears was a short term fix. I had many motors that I got this way.
And Ed V's article on the B25 crank leaks, good points there.
Jeff
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Re: B25 carrillo

Post by fastharry »

You might take a look at Thunder engineerings alloy rods for a 500 triumph. I believe they fit the B25, Very well made, I have fitted several sets to race engines with no problems so far, And far better value than Carrillo. Iv'e seen lots of comments saying do not use this make of shell or that make of shell, but no hint as to what to actually use these days. Its a real problem, i have asked several major suppliers as to what material is used and they have not got an answer. Worrying if you are building a race engine.
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Re: B25 carrillo

Post by kommando »

If you ask the supplier for a picture of the stamping on the back of the bearing and then post it here then I can try and say what material it is. Current Triumph Unit 500 shells made for Velocette Motorcycle Company Ltd run by Matt Holder are made from Al/Sn and this is the best current option but needs to have an oil filter in the return as its one downside over the Whitemetal originals is lower embedibility so does not absorb grit well.
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Re: B25 carrillo

Post by BSA_WM20 »

Jeff K wrote: Sat Nov 17, 2018 6:27 pm Kommando
Great answer on the T100 rods and as they say. Now I know. Years ago I used to be able to pick up B25 and TR25W all day long for $50.00, that probably explains why I still have well over a dozen of them. The three biggest reasons for them being parked was.
1. Spun main bearing.
2. Flogged to dead trying to compete with 2 cycles by young drivers.
3. Missing second gear.
#1 - A old Triumph shop mechanic told me decades ago that the old bikes did not have a oil filter and only used non detergent oil. Detergent oil keeps the gunk suspended so it can be filtered out. Non detergent allows it to settle on the bottom like in a lawn mower. The problem that he said was here in Michigan the bikes are parked all winter so gunk does settle to the bottom while setting for months. And then when some one changes the oil and uses the more common detergent oil. The detergent oil does it's job and picks up all of the gunk from the bottom and then suspends it in the oil. Problem is there is no filter to remove it so the oil becomes abrasive and the soft parts are the first to go.
#2- Teenagers trying to keep up with the much more powerful 2 cycle and beating on the poor old BSA's. I grew up next to a old abandon golf course that was for many year the best place to ride dirt bikes. And the kids on the TR25W would strip them down, add huge rear sprockets, etc while trying to keep up with the K*waski's, S*zuki's and Y*amaha's of the era. They beat them to death.
#3 - This might have just been a local thing. But a lot of the guys racing the B50 in local Motocross did not use the clutch at the start and would instead stomp the bike into 2nd gear while cranking the throttle wide open when the start flag would drop. The end results was they were always looking for 2nd gear sets. Decades ago I got the last 2nd gear set that MAPP had to sell and they also told me the same story and they added that sadly the B50 gears were harder then the early B25, so swapping gears was a short term fix. I had many motors that I got this way.
And Ed V's article on the B25 crank leaks, good points there.
Jeff
There are 4 oil filters in the engine, and each does a different job.
Anyone who tells your there are none is talking through their rectum and has little to no understanding of the engine, lubrication or oil flow.
1) Gauze filter on the scavenge side of the pump.
Sized so that anything that goes through the gauze will pass through the return side of the pump without causing pump failure
2) Gauze on the supply side of the pump, much finer than the return side and again if the crud passes through the gauze then it can pass through the supply side of the pump without causing pump failure.
3) full flow centrifugal oil filter inside the crankshaft, commonly & incorrectly called a Sludge Trap.
Centrifugal filters are the absolute best filters for removing particulates and they do so without any effect on the passage of the oil.
4) settleing tank. The returned oil goes into a deep tank where the outlet is higher than the bottom of the tank.
This allows particulate that are heavier than the oil to settle down past the inlet screen so go out of circulation.

A detergent oil can not ( in most cases ) break up the sludge in the bottom of the oil tank and even if it did it would not circulate because the resultant blob of gunk encapsulated by the detergent molecules would still be substantially heavier than the oil it is in so would stay on the bottom of the oil tank.
Even if the detergent could break up the sludge ( which it can not ), it still would not pass through the screen filter in the pick up line.
Using high detergent oils defeats the full flow centrifugal oil filter because the tiny particulates once encapsulated by the detergent molecules are less dense than the oil they are in so pass right through the "sludge trap" and rip up the bearing surfaces.

You will note that owners who fit external oil filters and use detergent oils will ignorantly & erroniously sprout out that their new filter is so efficient that there was nothing in the sludge trap after xx thousand miles and consider the absence of gunk in the crank filer as proof positative that the new system is orders of magnitude better than the original oil filtering system when in fact there is little difference in the efficency of the spin on filter as most are actually coarser than the original crank filter, they are just a lot easier to clean.
A crank filter can take out particulates down to 0.5 microns where as most paper oil filters are pushing it to remove particulates smaller than 20 micron.
The common filter used on spin ons is 20-40 icron, any finer and the pump could not keep up oil pressure unless the filter cartridge was around 3 times the surface area.

So BSA's do have filters, it is just the main one is a PIA to clean.
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Re: B25 carrillo

Post by kommando »

Well talking through my rectum, filters 1 and 2 are as much use as taste buds on a rectum, they are just tea leaf strainers and I do not brew tea in my engine oil.
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Re: B25 carrillo

Post by lathejack »

kommando wrote: Fri Nov 23, 2018 5:38 pm Well talking through my rectum, filters 1 and 2 are as much use as taste buds on a rectum, they are just tea leaf strainers and I do not brew tea in my engine oil.
Yes Kommando I quite agree, but not with the bit about you talking through your rectum. However I do think some should look closer to home regarding people sprouting ignorant errors through their rectum.
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Re: B25 carrillo

Post by BSA_WM20 »

As mentioned the gauzes are there for a purpose.
And that is to protect the oil pump.
So weather you brew tea in your cases or not, running without either of them can & does lead to total pump failure which will kill the engine in no time flat and no spin on oil filter will make a natts knickers of difference to the outcome.
But don't take my word for it, remove both of them from your bike & see how long it remains running.
Having pulled down way too many BSA engines over the years that suffered from a big end failure , the vast majority of them had oil galleries in the crank that were totally blocked off because the owners failed to clean out the FULL FLOW CENTRIFUGAL OIL FILTER, cleverly hidden within the crankshaft.

Perhaps if BSA had mounted it externally like H*nda did the interlectually challenged would have realized it actually does filter the oil and in fact filters it very well.

Total loss engines do not have oil filters .
Splash lubed engines do not have oil filters.
BSA's do and have been using full flow centrigugal oil filtering almost from the first recirculating oil engine they produced, back in the 20's.
The fact alone that so many of these engines still exist would tend towards the engineers at BSA having a modicum of understanding about oil flow & filtration above that of modern mechanics who can not understand that there are other methods of filtering oil apart from a replacible tin can full of pleated paper.

Of all people on this list I would have expected you to have a better understanding of filtration.
How long would a slipper bearing last being fed unfiltered recirculated oil ?
I am sure your labs would have done many series of tests to determine the bearing wear rates as a function of maximum recirculating particulate size.
With NO filtration I seriously doubt that a slipper would last much more than a few hundred hours.

The unfiltered splash mower engines have an expected working life of 10 years
10 x 30 ( mows a year) x 1.5 hours ( average domestic push mow time = 450 hours for an aluminium rod with no slippers, governed to < 4000 rpm running a compression ratio in the 7-8 range, a lot easier life than a B25 / C15, or even an A7/10 many of which have managed hundreds of thousands of hours with the same "NO OIL FILTERS" fitted.

And I prefer my tea with a twist of lemon rather than a hint of SAE 30 :lol:
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Re: B25 carrillo

Post by Jeff K »

I thought the the 2 "gauze' filters were nothing more the a fine wire mesh, The centrifugal I would agree would hold most fines. I can remember in the early 1960's, it was not that uncommon to take a car that had been mostly driven in the city was was sludging up the oil. The mechanic would drain the oil, but leave the old oil filter and its contains still on the car, add 3 to 4 quarts of fuel oil and then start the car up and let it idle for a short time. Then he would drain it again. It came oil black and thicker then when it went in. :( . So how is detergent oil not doing the same thing given a lot longer amount of time and a lot more rpm? I just know that on the B25 with it's "soft" plain bearings, I have seen many in great shape except the main bearing is worn out.
There are I think 9 250s on that side a couple more on the other side and a few more in the shed. Plus another six motors on the shelf. Most of them other then the 3 1971's have main bearing problems.
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Re: B25 carrillo

Post by BSA_WM20 »

The fuel oil or power kerrosene is a solvent and by the way also abrasive, as is distilate or diesel.
So again , not a detergency thing.
All that a detergent does is encapsulate a particle that is neither oil nor detergent.
Thus the particulates stay as very fine discreet particles in circulation in the oil making them easy for the filter to remove.
The detergents also have a lower specific gravity than the oil they are mixed into and over enough time will float to the top.
One reason for not using very old blended oil, at least not unless it is given a good shake.
The detergent molecules are lighter than the oil so the entire package of the impurity totally encapsulated by the detergent molecules tends to be lighter than the oil thus preventing it sinking to the bottom and forming a sludge that you used to see on the bottom of car engine sumps & built up inside rocker covers .
The mechanical turbulance of the crank splashing into the sump oil can mechanically dislodge sludge and over time if you are very slowly mechanically knocking off sludge and also preventing new sludge forming then over a very long period of time you can , under very strict conditions eventually remove accumulated sludge.However this can not happen in a dry sump fitted with a settleing tank that is specifically designed to have minimum turbulance.

The "cleans your engine while you drive" is a load of advertising bull dust originating from a drunken coppywriter remembering that the wife had a bottle with the word detergent on it in her hands and the plates came out cleaner when she used it before he beat her senseless because one of them was not spotless.
The really annoying thing is how persistent this bull dust has become when even Wikki & Face book both have the definition of detergency correct.
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Re: B25 carrillo

Post by BSA_WM20 »

double posted
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