Thread: Blowby

Originally Posted by 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

Did you ever find that seal number?

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.

Originally Posted by Dougal

Did you ever find that seal number?

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

Originally Posted by LOVEMYRANGIE

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.

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.

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.

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

Originally Posted by 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

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