Blowby

[Dougal]

Well dammit it looks like I've got huge amounts of blowby again.

The engine was leak free for the last 1000km or so, then I decided to chase a merc ML320 up a few hills (actually a 1000m mountain pass). Looks like the crankcase pressurised enough to vent through the rear crank seal. Lost a bit over 2 litres of oil I think.:(

I did the rings, pistons and liners not very long ago (almost 3 years, not quite 30,000km). The ring gap was slightly bigger than ideal (16-18 thou) but straight after the rebuild it idled so cleanly you could see up the exhaust.
Now I've got some blue smoke after startup and an oil cap that won't stay put at cold idle.

Still starts fine and power levels are great. This thing does mostly open road work so glazed bores aren't suspected.

What to do?

[balki]

hi have you checked the big breather on right hand side of engine to see thats its clean some of the have a removable top and a mesh thing that gets clogged up if yours is sealed soak it in petrol and hit it with a karcher thats where all the breathing should be coming from if its breathing

[Larns]

Not really sure what to say, I know when I rebuilt my engine I was checking on something whilst the engine was running and I thought my rings were gone, as there was so much crank case pressure that the oil cap would pop out if I wasn't holding onto it. Thats alots of pressure!!
Did a fair bit of testing and found everything normal. It was just the shear fact that every time a piston moved up or down nearly a litre of air was being displaced.
Maybe you CCV breather is blocked?
Did you speedi sleeve your rear main crank surface?
I've seen the rear main seal catch on speedi sleeves and after a while they just start pumping out oil.

Hope its not the rings mate, you'll have to do a compression test.

Good luck

[Dougal]

The oil trap is my own design, it's a cyclone type which has no mesh or screen that can block up. But downstream of that it plumbs into the intake just before the turbo, I should replace that hose with a larger one.

The rear crank surface was speedi-sleeved some time ago and it's still good. Well it was when I checked it around 10,000km ago and changed the seal. I should warm the engine up, pull the breather off and see what's actually coming out.

Does anyone know if the oil filler cap will stay put on a healthy 4BD1T?

[Larns]

Not unless it's on tight, mine will blow off if loose

[1103.9TDI]

Mine stays put, and I have healthy blowby through the breather. There are a few different type of oil filler caps; my original was a bit on the suspect side, so I ordered a new one from Isuzu. It was quite different, and made out of a more rubbery compound. Maybe order one of these, they push in very securely.

[Pedro_The_Swift]

with the wider than normal ring gap,,
could they have all lined up?

[Dougal]

Not unless it's on tight, mine will blow off if loose

I should clarify that a little.
Mine will stay put every time it's in. But when sat loosely in place it gets blown clean off.

Jeeze I hope the rings couldn't have lined up. They were installed with the gaps 180 deg out and I'm hoping they'd all rotate the same amount in the same direction.
Compression appears fine from a starting point of view. It's just the blowby that has me concerned.

Maybe an additional breather is in order.

[Bearman]

Hi mate, Blowby seems to be a normal thing with these motors. What Isuzus dont like is too much idle work.If compression figures are ok and it seems to be going alright dont worry about the blowby.Work it as hard as you can.I havent seen one yet that has little or no blowby.Regards....Bearman

[rovercare]

Hi mate, Blowby seems to be a normal thing with these motors. What Isuzus dont like is too much idle work.If compression figures are ok and it seems to be going alright dont worry about the blowby.Work it as hard as you can.I havent seen one yet that has little or no blowby.Regards....Bearman

Yea, both my rebuilt AND 290k old 4BD1's breath heavy

[EchiDna]

Italian tuneup time :)

mine has blowby, but not measurable in litres!!

[Dougal]

Italian tuneup time :)

mine has blowby, but not measurable in litres!!

What exactly is an italian tune up?
And why does my rear main seal leak when no-one elses does?

[rovercare]

What exactly is an italian tune up?
And why does my rear main seal leak when no-one elses does?


Flog da fug outta it maaaaayte:D

Incorrect fitment:p

Bad seal?

Leaking compression?:(

[Vern]

Yea, both my rebuilt AND 290k old 4BD1's breath heavy
Don't forget my chev, that was breathy aswell

[rovercare]

Don't forget my chev, that was breathy aswell

Mine ain't that heavy:D

[Dougal]

Flog da fug outta it maaaaayte:D

Incorrect fitment:p

Bad seal?

Leaking compression?:(

Trust me, I do.
Did I not mention I was chasing a mercedes over a mountain pass.:cool:
20psi boost sustained for about 5 minutes.

This is the third seal that I've fitted, it's a genuine Isuzu (made by NOK) and I even cut 10% out of the spring to give it some more tension. Crankshaft surface is good (speedisleeve).

Bigger breather maybe. I need to put a pressure gauge on the dipstick tube and go for a drive. See if it's pressurising.

[rovercare]

Trust me, I do.
Did I not mention I was chasing a mercedes over a mountain pass.:cool:
20psi boost sustained for about 5 minutes.

This is the third seal that I've fitted, it's a genuine Isuzu (made by NOK) and I even cut 10% out of the spring to give it some more tension. Crankshaft surface is good (speedisleeve).

Bigger breather maybe. I need to put a pressure gauge on the dipstick tube and go for a drive. See if it's pressurising.

Well you've got a boost gauge;)

Dodgy up a bit of pipe and go for a spin, will wait for your post in half an hour or so:D

Mightn't be able to build pressure if your rear main is that bad:(

[Dougal]

I'm on holiday at the moment (going skiing again tomorrow:)) so give me a week and I'll see what I can find.

[Larns]

The original Isuzu rear mains arn't that crash hot. Seriously, the Aust. army has loads of trouble with them! I've replaced three in a row on one of their 6x6's, belive me it's the seals. There is a new type of rear main seal available now. It has to be pressed into the adapter housing and has a "sleeve" built into the seal that presses onto the crank, this superseeds the need for a speedi sleeve, the seal is a three lipped job. I installed one onto mine upon rebuild and so far so good (29000km)
I'll track down the Pt no. tomorrow if I remember.

Just out of curiosity what type of oil fill caps are people running, mine is a screw in type. It sounds like people have the push in type with a turbo'd engine.

:twobeers:

[Dougal]

The original Isuzu rear mains arn't that crash hot. Seriously, the Aust. army has loads of trouble with them! I've replaced three in a row on one of their 6x6's, belive me it's the seals. There is a new type of rear main seal available now. It has to be pressed into the adapter housing and has a "sleeve" built into the seal that presses onto the crank, this superseeds the need for a speedi sleeve, the seal is a three lipped job. I installed one onto mine upon rebuild and so far so good (29000km)
I'll track down the Pt no. tomorrow if I remember.

Just out of curiosity what type of oil fill caps are people running, mine is a screw in type. It sounds like people have the push in type with a turbo'd engine.

:twobeers:

Got a part number for this super seal?
I know people who work for companies that just import and sell seals. I have the measurements somewhere so I'll see what they come up with.

Yep I've got the push in filler cap. Mine is a JDM 4BD1T truck engine. It's got the rocker cover with the short hump in it.

[incisor]

interesting thread to say the least.

as an aside, anyone know of a list of isuzu engine numbers that gives you the original specs of that engine eg turbo / non turbo or what it was out of etc etc?

[Larns]

The improved rear main seal is by SKF there are a few pt no's on the pkt so I'll list them all.
The first one seems like a Landy one-BYG 2767
2. 200610-0218-03-03
3. #550651

I got mine about three years ago from SKF and from memory it was a bit hexy at around 80-90 buck mark.

Well worth the money though as I havn't had a drop of oil since. Oh and if you do get one they need to be oiled as I've heard of them chewing out. I'm not quite sure how your ment to do this but I used a needle and worked it under the lip and injected oil in that way.

Good luck though.

[rovercare]

What happened with this Dougal?:confused:

[Dougal]

What happened with this Dougal?:confused:

Not much yet.

I've done the same trip since and found that not keeping the boost needle pinned at 20psi for 5 minutes at a time lets the oil seal do it's job properly. I haven't had the time to pull the engine and replace the seal and laziness has kept me from measuring crank-case pressure.

I've also got a transfercase input seal which is making all other oil leaks insignificant. Didn't leak a drop for 10,000km then boom, drops a litre. I think the seal has popped either into or out of the case.

Factory rear seal (the one that's currently in there is genuine and maybe 20,000km old) is a:
NOK BH2195E
135mm OD
100mm ID
10mm thick.

[justinc]

I gave mine a BIG go the other day up some big hills at full noise, when I parked up at work faciing slightly downhill, I came out several hours later to find a small(70mm across) oil puddle under the bellhousing drain:o

Hasn't happened before or since. Breathing from the engine hasn't appeared to be any worse since then either. It does get worked hard towing defenders and discos etc from time to time, haven't noticed this oil leakage before now though. The rear seal on this engine has done 500,000+km, and is a 21years old next year.

JC

[rovercare]

Mine has gearbag oil coming from the drain plug:(

[1103.9TDI]

I've had one of those new-fangeled rear main seals in for almost a year now, with no leaks:) touch-wood. It's well known that these engines are sus for rear main leaks, mine was not an exception, but these new seals appear to do the trick.

Now that I've said that it'll start leaking next week.........:D:D:D

Sorry Dougal, can't contribute much to your problem except maybe a blockage in your breather line, at any rate tick the simplest items off first before you reef the engine out:D.......

If you get one of those new seals, it needs to be fitted carefully with a special tool (normally) I think we did it with a piece of 75 and 100mm pipe, and a bit of goop:D

[Blknight.aus]

dont forget to check the back of the bottom half of the rear main seal housing for the mod hole thats the oil leak back to the sump. it stops your rear main from having to hold back main oil pressure and puts it back to plain old splash oil only.

[Dougal]

dont forget to check the back of the bottom half of the rear main seal housing for the mod hole thats the oil leak back to the sump. it stops your rear main from having to hold back main oil pressure and puts it back to plain old splash oil only.

Got any more info on this Dave?

[Bearman]

There does seem to be some similarities in when this is happening. Going up hills and hard revving. Maybe there is a pressure shock from No.4 big end crankshaft lobe hitting the oil pooled at the rear of the sump and forcing it past the seal. Any thoughts???

[Dougal]

There does seem to be some similarities in when this is happening. Going up hills and hard revving. Maybe there is a pressure shock from No.4 big end crankshaft lobe hitting the oil pooled at the rear of the sump and forcing it past the seal. Any thoughts???

No hard revving in my one, it spends it's time between 1500-2500rpm. Those hills are the only time I get a sustained high load. The only thing comparable load-wise would be towing a big trailer into a strong wind and I don't do that.

[Bush65]

dont forget to check the back of the bottom half of the rear main seal housing for the mod hole thats the oil leak back to the sump. it stops your rear main from having to hold back main oil pressure and puts it back to plain old splash oil only.


Got any more info on this Dave?
Land Rover 4BD1's mount the seal in the flywheel housing, where the truck engine has a separate seal housing, so there may be some difference in small details like drain holes.

i have one of those BYG 2767 seals, but haven't fitted it yet. May pull the seal housing and fit the new seal later in the week so will check it out further then.

BTW the seal is branded CR, which stands for Chicago Rawhide (a large seal manufacturer bought out by SKF). But going by the label it was probably manufactured in Japan.

[Blknight.aus]

rough as gutsly....

the mod is about a 3mm hole drilled at about a 40 degree downwards angle through the base of the seal mount more towards the front of the engine than where the traditional seal sits.

I'll see if I cant dig up the EMEI.

[clean32]

would it make a difrence if you have the winged or truck sump ?

[LOVEMYRANGIE]

Dougal
When you had the speedi-sleeve fitted, did you size it according to the seal ID or the crank OD??
When sleeving, you need to ensure the crank has a relief machined to take the sleeve leaving it with the original seal run diameter. If you use a sleeve that just goes over the original seal face, it will stretch the seal and put higher face load on it causing it to wear, not to forget that it makes the lip edge sit at a different angle on the crank.

[Dougal]

Dougal
When you had the speedi-sleeve fitted, did you size it according to the seal ID or the crank OD??
When sleeving, you need to ensure the crank has a relief machined to take the sleeve leaving it with the original seal run diameter. If you use a sleeve that just goes over the original seal face, it will stretch the seal and put higher face load on it causing it to wear, not to forget that it makes the lip edge sit at a different angle on the crank.

The seal is ontop of the crank surface, increasing the diameter by about 2/3 of a millimetre.
It's not seal wear as even new seals weep. Tightening the energising spring helps a little but doesn't cure the problem.

[LOVEMYRANGIE]

The seal is ontop of the crank surface, increasing the diameter by about 2/3 of a millimetre.
It's not seal wear as even new seals weep. Tightening the energising spring helps a little but doesn't cure the problem.

It wont cure it because the extra diameter makes the seal lips expand away from each other causing it to flatten out, even with such a small increase in diameter.
Either that or you just have a crap seal.
I dont have all my info on hand now as I have left SMS Diesel and moved to R. Moore & Sons Diesel Engineers, but I will see if I can find out any differences for you. Give me a couple of days.

Cheers

Andrew.

Not a commercial banner here, but this job is FAR more interesting! Have a look at the website gallery and see what I get to play with now!! Check out the Waukesha!

R.Moore & Sons - Diesel Engineers (http://www.moorediesel.com)

[Dougal]

Either that or you just have a crap seal.


That's my suspicion. I'll throw in a better one next time I have the engine out and see how it goes.
I had a short holiday with no seal leaking, that was between the time I fitted my new crank main bearings and the time I flogged it hard up that mountain pass.



I dont have all my info on hand now as I have left SMS Diesel and moved to R. Moore & Sons Diesel Engineers, but I will see if I can find out any differences for you. Give me a couple of days.

Cheers

Andrew.

Not a commercial banner here, but this job is FAR more interesting! Have a look at the website gallery and see what I get to play with now!! Check out the Waukesha!

R.Moore & Sons - Diesel Engineers (http://www.moorediesel.com)

That's a nice 1500hp dyno you have there.:eek:

[LOVEMYRANGIE]

That's my suspicion. I'll throw in a better one next time I have the engine out and see how it goes.
I had a short holiday with no seal leaking, that was between the time I fitted my new crank main bearings and the time I flogged it hard up that mountain pass.



That's a nice 1500hp dyno you have there.:eek:

Mmmmmmm isnt it!!! Wonder if I can clock it with the Rangie........ not!!!!
You should have heard the K50 we had on it today with no exhaust at full note!!!

Ok, your seal, did some checking. Two dimensions based on year.
Up to 1984 - dimensions 135x100x10
'84 on - 135x100x15.

At SMS we never carried the early seal and AFAIR the later seal was not a supercession because of a carrier change/difference.
Check to see you havent had a 10mm seal put in place if it originally had 15mm one. Other than that, i would really be checking crank dia and making sure its 100mm exactly.
And OEM for the seal should be Ishikawa, but NOK would be as good if not better.

Cheers

Andrew.

[Dougal]

Mmmmmmm isnt it!!! Wonder if I can clock it with the Rangie........ not!!!!
You should have heard the K50 we had on it today with no exhaust at full note!!!

Ok, your seal, did some checking. Two dimensions based on year.
Up to 1984 - dimensions 135x100x10
'84 on - 135x100x15.

At SMS we never carried the early seal and AFAIR the later seal was not a supercession because of a carrier change/difference.
Check to see you havent had a 10mm seal put in place if it originally had 15mm one. Other than that, i would really be checking crank dia and making sure its 100mm exactly.
And OEM for the seal should be Ishikawa, but NOK would be as good if not better.

Cheers

Andrew.

My seal is definitely 10mm thick (I have the old one in a box here, new was identical), but there's heaps of space for a 15mm version.
My engine is a JDM truck motor and approx 85/86 model year, the NOK seals were bought in Isuzu bags/kits from dealers here about two years ago.

[C H T]

Dougal

I have fitted a genuine Isuzu wear ring/seal to my 4BD1T - no leaks! I will dig out the part numbers for you before the weekend. The wear ring is like a very thich speedi-sleave. OD is 105mm the ID of the seal to suit is larger to suit the wear ring - all su[pplied from Isuzu

Christopher

[Dougal]

Dougal

I have fitted a genuine Isuzu wear ring/seal to my 4BD1T - no leaks! I will dig out the part numbers for you before the weekend. The wear ring is like a very thich speedi-sleave. OD is 105mm the ID of the seal to suit is larger to suit the wear ring - all su[pplied from Isuzu

Christopher

Did you ever find that seal number?

[Bush65]

The number was posted somewhere in this forum. I went out and bought one from a place that has a contract to overhaul the military Land Rovers.

Stamped on the seal is 'CR' and 'BYG2767' ('CR' is the seal manufacturer Chicago Rawhide).

The sticker on the package has NSN: 5330-66-149-1912 and bin location S56B15MISC.

This sticker is over the top of the original 'CR' label on the package. I can make out BYG2767, but there is another string of numbers on the row above that I can't make out.

[LOVEMYRANGIE]

Did you ever find that seal number?

I gave you all the seal numbers ages ago didnt I??? Thought I posted it somewhere here....??

[Dougal]

I gave you all the seal numbers ages ago didnt I??? Thought I posted it somewhere here....??

There were numbers posted up earlier, just wanted to check they were the same.:)

[110Landy86]

Hi guys firstly I'd just like to say that as Gerry has done, i replaced the original oil filler cap with one comprised of a more 'rubbery' compound which presses in and is very secure.

I have a few questions re. blow by from the ccv breather.

Bit of background info:

Engine (N/A) has done 402,000 km and is regularly serviced (one owner). On start up the exhaust gases are ~95% black with the remaining bluish. When revving the engine with no load the exhaust smoke is black.

After the engine has been running at operating temp for a while there appears to be an visible amount of blow by emanating from the ccv breather such that it is visible in the car headlights (looking back at the vehicle at night) though blowby is merely visible when inspecting the engine bay. Furthermore, when putting the boot in during hill climbs or accelerating at highway speeds i.e. 100km/h + the exhaust smoke isn't completely black as it does contains some blue (again minor component).

Close inspection of the ccv breather indicates the presence of some oil residue (which i am told is normal???) while the exhaust pipe has only black soot. I have since cleaned out the ccv breather using a load of degreaser and petrol/ hot water. The oil filler cap does bubble about the tapet cover aperture when placed atop but generally doesn't fall off. I haven't carried out a compression test, though oil consumption between services, i believe, is insignificant.

I know it is "wrong" to compare engines of different makes however after recently driving a late model cruiser (work vehicle) I've observed pretty much zero emissions with only black smoke during heavy throttle.

Basically, i intend on fitting a turbo to this engine however fitment is subject to the condition of the engine internals. I understand that these engines are generally capable of up to 1,000,000 kms between rebuilds.

Given the above, I ask this:

1) Is the trace blue smoke in exhaust gases coupled with blow by as described normal/ merely a symptom of lack of air/ partially clogged injectors (???) or something more deeply seated.

2) Based on the limited info i have provided, what is the general consensus on the condition of this engine w.r.t turbocharging.

Any comments are much appreciated. :)

Thanks in advance

Joe.

[Dougal]

Blue smoke on my engine was due to worn valve guides dropping oil into the intake and exhaust ports.
The oil dropped into the intake caused gumming of the piston rings in low load (i.e. around town) driving which compounded the problem, the oil dropped into the exhaust ports was the cause of the blue smoke. Under load my blue smoke disappeared but at idle it was like a 10 year old mitsubishi.

I gave the engine an insitu rebuild at this point and all problems went, but I knew I had bore problems (wrong rings ate my liners in 27,000km) as well as the worn out valve guides and seals.

[110Landy86]

Anyone know the compression specs for 4BD1...I've got some suspect bluish smoke under load...Doesn't use any oil between services but *shrug*...Process of elimination!

Cheers

[isuzurover]

Anyone know the compression specs for 4BD1...I've got some suspect bluish smoke under load...Doesn't use any oil between services but *shrug*...Process of elimination!

Cheers

I would be able to tell you, but my manual is in perth. However I reccommend you buy or photocopy an isuzu truck workshop manual. This is the one I have:


Workshop Manual
N Series
applicable to all vehicles in all countries except USA and Canada
Manual applicable to 1985 and later model years
First Edition, September 1988 1008-25K-1
PN: LG4BE-WE-58G

[Dougal]

441 psi at 200rpm at sea-level.

But blue smoke won't normally be rings as diesels don't have the vacuum to pull oil up past them. The only time I've had blue smoke was worn valve guides and seals mentioned a couple of posts up.

[Dougal]

And just a wrap up to the original concern on this thread.

I was always a bit worried that the original rings (genuine Isuzu) had a larger ring-gap than most, all the engine builders/enthusiasts I talked to were working on a 3 thou per inch plus 3 thou rule of thumb, which for our engines is 15 thou. But the Isuzu rings in a new sleeved bore measure 16-18 thou.

It was only recently I realised I'd been talking to non-turbo engine builders, turbo engines need a bigger ring-gap as the average cyilnder temperature is higher, the boost they are fed is hotter than ambient by enough to make a difference. This was under-scored by a freshly rebuilt perkins (perkins have very little blowby) chewing up a cylinder liner when it was turbocharged. Re-doing the perkins with a larger ring-gap has solved that problem.

This follows what one helpful gentleman posted up on 4btswaps about cummins 4BT ring gaps:

N/a top ring gap is min. 0.25 max 0.55 the turbo top ring gap is min 0.40 max 0.70

Those are in mm's, in thou they are:
NA: 10-21
Turbo 16-28

So the Isuzu 4BD1T factory rings have a gap which sits nicely at the lower end of the cummins ring-gap spec. Which makes me very happy.

In a nut-shell, we're never going to get a highly boosted tdi to run with minimal blowby at idle. They will always breathe plenty when cold and need breathers that can handle this. I still haven't increased the size of my breather hoses but it's on the list and the pro-vent is here waiting.:cool:

[110Landy86]

I recently noticed some oil residue on the engine oil dipstick (outer casing ;)) of my 4bd1t. The dipstick grommet is a fairly tight fit.

After a long drive over mountainous country and driving it fairly hard, I popped the hood to notice some oil on dipstick. I then removed the oil filler cap with the engine running. I noticed a discrete puff of greyish gas immediately upon removal then nothing, apart from the occasional oil flicker.

This has never happened before however to me it suggests high pressures in the crank case.

I'm running a provent connected to the side crank case port through a series of 1 1/2 / 1 3/4" rub flex hoses. The valve cover is the 4bd1 type with ~1/4 - 1/2" line connected to the intake (pre-turbo). I've had the provent connected for approx 8000 km and there's about 20 ml of oil accumulated (i.e. bottom of filter still clean).

Engine starts first pop (always has) and no noticeable decrease in power.

I hope this is simply due to inadequate cc ventilation and not worn internals. Any thoughts on this and what my options are i.e. does it require immediate attention?

Much appreciated for your comments.

Cheers.

[isuzurover]

I recently noticed some oil residue on the engine oil dipstick (outer casing ;)) of my 4bd1t. The dipstick grommet is a fairly tight fit.

After a long drive over mountainous country and driving it fairly hard, I popped the hood to notice some oil on dipstick. I then removed the oil filler cap with the engine running. I noticed a discrete puff of greyish gas immediately upon removal then nothing, apart from the occasional oil flicker.

This has never happened before however to me it suggests high pressures in the crank case.

I'm running a provent connected to the side crank case port through a series of 1 1/2 / 1 3/4" rub flex hoses. The valve cover is the 4bd1 type with ~1/4 - 1/2" line connected to the intake (pre-turbo). I've had the provent connected for approx 8000 km and there's about 20 ml of oil accumulated (i.e. bottom of filter still clean).

Engine starts first pop (always has) and no noticeable decrease in power.

I hope this is simply due to inadequate cc ventilation and not worn internals. Any thoughts on this and what my options are i.e. does it require immediate attention?

Much appreciated for your comments.

Cheers.

Try cleaning your provent element using the method I have described elsewhere.

You can also pull the provent element and see if the problem goes away.

However it doesn't sound bad - some breathing is normal. The extra pressure drop across the provent element will find any seals that aren't 100%. Is the leak from the top of the dipstick tube or the bottom where the o-rings are?

[110Landy86]

Thank you, I do plan on trialling a few options on the we. Cleaning the provent with petrol should be right...I will then removing it temporarily just as you suggested and see if there is an improvement.

Oil is coming up and out of the top of the dipstick tube. There doesn't appear to be any oil at the base.

I would have thought there would be more blue smoke and harder starting if it were something major?

[isuzurover]

...Cleaning the provent with petrol should be right...

NO - I would advise against cleaning it with petrol. I have posted how to clean them using compressed air - the thread is in the good oil I believe.

[Dougal]

Just to wrap up this thread.

The crankcase pressurising problem under high load was solved by a bigger breather setup. I went to a provent but then had problems with the provent sucking oil out the sump and feeding the engine.
I reversed the flow of the provent to keep the oily and clean sides further seperated and this is now working very well. But I still have to repair the damage from injesting a lot of oil (enough for it to run on it's own oil several times).

I'll be making a new catch can setup at some stage to fit in the original location (provent with reversed flow is too big and inlet/outlets in the wrong places) but with 1" hoses going in and out.

I'll also be going to back to factory matched piston/liner/ring sets which should have a slightly tighter ring-gap than the aftermarket items I'm currently using.

[Judo]

What size breathers did you change to Dougal?

[Dougal]

What size breathers did you change to Dougal?

I stepped straight into 1" from the rocker cover. But this size doesn't fit well past the throttle linkage, next time I'll keep 16mm from the rocker to the catch can but make sure the fitting on the can has the biggest internal bore possible. I'll do 1" from the can to the intake.

[Judo]

I stepped straight into 1" from the rocker cover. But this size doesn't fit well past the throttle linkage, next time I'll keep 16mm from the rocker to the catch can but make sure the fitting on the can has the biggest internal bore possible. I'll do 1" from the can to the intake.
Just the one breather? No side cover breather then?

[Dougal]

Just the one breather? No side cover breather then?

Just the one. Factory t model.