2.25 petrol engine problems

[littlelegs]

View attachment 112813View attachment 112812View attachment 112811View attachment 112810Hello All
Here is some pictures of my breather system, but I don't have any pics of it being installed,but "Littlelegs" gets the idea.
Do I need a source of fresh air in there as well, so that it doesn't cause a vacuum and therefor maybe suck up the oil?
Will check into that, maybe it sorts out the problem.
H

The system needs air coming in at one end and exiting at another, taking with it any gasses and oil mist. Presumably your system is designed to return or contain the oil, however, if there is no air inlet or even a PCV in the system then the vacuum created in the crankcase by the engine acting as a vacuum pump can be considerable and can implode seals and gaskets or draw up oil! I suggest trying only one connection to the rocker cover and fitting an air intake filter to the front breather/filler to give that through put of air, you may still need a PCV to limit the vacuum when the throttle is closed at high revvs.

 

[littlelegs]

Hey guys, we seem to be going around in circles a bit on this one!

Forgetting Heinie's problem for a bit and using my vehicle as an example (same apparent fault remember) my engine has been fully rebuilt (twice actually!). And ALL of the following have been carried out:

1. Rebore, new pistons/rings fitted - correctly gapped and spaced.
2. New Camshaft bearings. (Twice)
3. New oil pump.
4. New distributor.
5. New baffle plate at base of oil filler/breather.
6. Crank ground/new shells fitted.
7. Head skimmed.
8. New radiator.
9. New water pump.
10. New timing chain.
11. Both oil filler breather and rocker cap thoroughly cleaned out in gasoline.
12. Valve clearances correctly set.
13. Valve timing set correctly.
14. Ignition timing set correctly.
15. New seals and gaskets throughout.
16. New oil feed pipe to cylinder head.

As you would expect with a rebuild of this magnitude, pretty well all that needs changing/setting/machining etc, has been done - and STILL I have this oil problem!

My problem started AFTER the first rebuild when the cam-bushes had been replaced the first time and I'm wondering whether damage has been caused around the front cam bush/oil gallery area (at the base of the breather/filler neck) which shows itself ONLY when the engine warms up? A hairline crack for instance?

Well, I don't wish to hijack Heinie's thread - but as you can see, my delving into a similair problem as his has been somewhat comprehensive.

Hope the above helps?

Best Wishes
George.

I think you said you had no engine crank ventilation system so maybe that is also your problem.

 

[MPi-KMS-72]

View attachment 112813View attachment 112812View attachment 112811View attachment 112810Hello All
Here is some pictures of my breather system, but I don't have any pics of it being installed,but "Littlelegs" gets the idea.
Do I need a source of fresh air in there as well, so that it doesn't cause a vacuum and therefor maybe suck up the oil?
Will check into that, maybe it sorts out the problem.
H

Why did you make this?

Unless you have emmisions regulations to deal with couldn't you just make a simple "road draft tube" type system?

 

[Heinie1978]

Why I built the breather....

Firstly I had oil blowing out before I had the breather, and after reading a bit I found out I had no breathing system what so ever. Secondly I thought by putting in some sort of breather that will also capture any oil blowing out I would remove the problem of oil blowing out. Now I know that even with this breather fitted oil blows out.
Yesterday when I went to take a look I found the battery dead. Now I dont know if it is dead because it's been standing for a while or if any of the cells are dead, but will check out once I got the battery sorted.

 

[littlelegs]

Why I built the breather....

Firstly I had oil blowing out before I had the breather, and after reading a bit I found out I had no breathing system what so ever. Secondly I thought by putting in some sort of breather that will also capture any oil blowing out I would remove the problem of oil blowing out. Now I know that even with this breather fitted oil blows out.
Yesterday when I went to take a look I found the battery dead. Now I dont know if it is dead because it's been standing for a while or if any of the cells are dead, but will check out once I got the battery sorted.

I can't think that the engine would have no breather system at all, is it possible the engine has at some time been sealed for transporting or even selling?! Why not try refitting it back to how it should be originally then if it still smokes it has to be a worn or exhaust gas leaking engine.

 

[Snagger]

I think this breather system is making things worse, but you may have problems with bad gaskets/seals, poorly prepared sealing surfaces or incorrect spec machining (eg crank shaft ground too narrow on seal lands).

The problem could be block pressurisation, like I suffered with a 12J engine that had been rebuilt. It transpired that the 2.25 exhaust had caused the engine to run a bit hot, and though it never went very near the red arc, the cumulative effect was to crack the pistons, causing the compression and combustion gasses to leak into the crank case and force oil out of various gaskets, seals and blanking plugs. New pistons and the correct bore exhaust cured the problem for good.

 

[littlelegs]

I see you've cracked 15000 Snagger, do your family know who you are?

 

[Heinie1978]

Hey, I bought the engine second hand, but it has been reconditioned. So much so that I had to replace the piston rings 45 days after delivery.
Now that you mention something of exhaust, I got a new question that may be the underlying problem..

A few months ago I found that the exhaust manifold leaked where it connects to the exhaust pipe. Fixed it and everything went smooth.
When the oil blew out the other day, I found the exhaust manifold had once again pushed out the exhuast paste and was leaking. After I fixed the exhaust manifold seal the first time, the oil pressure on my gauge increased. Now that it leaks again, the oil pressure had a slight drop at tickover.
Is it possible that the exhaust has anything to do with oil pressure or am I clutching at straws?

H

 

[secondjeremy]

No the exhaust is entirely separate from the pressure oil system.

Your variation in pressure may be caused by fluctuations in idling speed.

 

[freqmikey]

Heinie, have you tried running the engine without any of the breather system ?? - it should run fine with the rocker cover and crankcase breathers vented to the outside world ... it would be interesting to note what changes you get, if any, by going back to nearer the standard set up.
Also, there's an oilway core plug in the head...is it sealed ? ... it probably wouldnt make oil come up the filler neck but could potentially flood the rockers and followers etc and pour out from the rocker cover gasket...???

Looks like you've got the eternal manifold leak with the exhaust....on mine anyway the single pipe waggles about enough to continually break the seal to the manifold...have tried various ways of making it more solid but havn't made it last more than a few weeks whatever ...in my case a new manifold is the answer but my OCD* keeps me there, trying to fix it

(it should really be CDO, that's alphabetical order...it annoys me when they put it in the wrong order )

 

[DarrenH]

No the exhaust is entirely separate from the pressure oil system.

technically it could have an effect, since an exahust leak would cause EGT to sky rocket (due to secondary combustion) which could increase engine running temps, and thus make the oil thinner reducing pressure.

Looks like you've got the eternal manifold leak with the exhaust....on mine anyway the single pipe waggles about enough to continually break the seal to the manifold...have tried various ways of making it more solid but havn't made it last more than a few weeks whatever ...in my case a new manifold is the answer but my OCD* keeps me there, trying to fix it

my experience of the exhaust flange is similar, i never seem to be able to tighten them enough. i tighten the nuts, and as soon as it gets one heat cycle under its belt i tend to get a leak on cold starts (with the farting blowing exhaust noise) which then stops after a few seconds as the join heats up and closes. its a kind of ball and socket join so maybe this is normal. i;ve not found a combination of tightening (hot or cold) that was overcome it.

 

[DarrenH]

forgot to say, the later 2.25 engines (i.e like late Series III and LR90) have an oil seperator on the rocker cover which is "sucked" by the inlet manifold and carb.

not sure on the logistics of doing this to an early engine, but would probably cure the issues mentioend by heini. there are several benefits to having the crank case evacuated, sucked, rather than just venting to atmosphere

 

[biosbill]

Why did you make this?

Unless you have emmisions regulations to deal with couldn't you just make a simple "road draft tube" type system?

Mine is an early 3-main brg and had a breather from the rocker cover to the air intake tube, thats still fitted. But on the oil filler (a long tube on the side of the engine on this one) it had a little pipe hole, when I got it this had nothing fitted and used to splash oil about, so I just added a bit of tubing that points up and backward: so it doesnt get water in when wading.

William

 

[solemnwarning]

Mine is an early 3-main brg and had a breather from the rocker cover to the air intake tube, thats still fitted. But on the oil filler (a long tube on the side of the engine on this one) it had a little pipe hole, when I got it this had nothing fitted and used to splash oil about, so I just added a bit of tubing that points up and backward: so it doesnt get water in when wading.

William

I fitted something similar, with a loop and filter to keep crap out.

 

[Snagger]

I run a Tdi and before that had a 2.5nad, so haven't worked on a petrol engine in a long time, but the exhaust and manifold are basically the same as on the 2.5nad (except the bore diameter), so the principles should be the same.

I kept the joint dry and never had any sealing problems. the nuts never seemed very tight, but there were no soot marks to indicate a leak. Pipe vibration and wobble may just be forcing the paste out without having a gas leak.

There is a slim chance that an exhaust blockage could be back pressuring the system, forcing the paste out of the joint and also forcing exhaust gasses past the valve stemn seals as the valves open, which would result in the gasses entering the rocker cover and working down into the crank case from there, giving the oil loss issue you are concerned about. This would manifest itself in sooty oil, poor performance and poor economy.

 

[freqmikey]

There is a slim chance that an exhaust blockage could be back pressuring the system, forcing the paste out of the joint and also forcing exhaust gasses past the valve stemn seals as the valves open, which would result in the gasses entering the rocker cover and working down into the crank case from there, giving the oil loss issue you are concerned about. This would manifest itself in sooty oil, poor performance and poor economy.

I wondered a similar thing with Heinie's motor, but perhaps with the inlets not closing properly (as well or instead) ..and it back pressuring the system through the rocker and manifold etc but .... seems a long shot

I know for sure that my exhaust manifold leaks because only one of the three nuts will do up roll on the summer autojumbles

 

[littlelegs]

I wondered a similar thing with Heinie's motor, but perhaps with the inlets not closing properly (as well or instead) ..and it back pressuring the system through the rocker and manifold etc but .... seems a long shot

Yup, that's a long shot. A partially blocked exhaust would give poor running, don't recall that was a prob.

 

[freqmikey]

Yup, that's a long shot. A partially blocked exhaust would give poor running, don't recall that was a prob.

Especially when I put my sensible head back on and look at the pics of the breather system again... Where does it live under the bonnet ? it looks fairly big...and I agree with ideas of it being a vacuum chamber that's sucking the oil out...the manifold will suck that volume of air in no time, especially if there is no way for outside air to get in. Try removing the pipe to the inlet manifold and vent to the atmosphere from the device...it'll work as a catch can but wont create a vacuum in there

 

[Georgedubya]

Does anyone actually read and digest what previous posters have put up on these boards?
As I said before folks - we're going around in circles.................

 

[Heinie1978]

Hello all.
I do agree with George.
This is on the other hand a very wierd occurance.
As for me, bought a battery charger yesterday and once I'm back hoem, will charge bat and run engine without breather and see what happens and will come back with my findings.
As for the breather, I will drill a hole in it and fit it with one of those smaller breathers, so that it can not cause a vacuum.
Also see what this can do.

The breather is connected next to the radiator against the left hand wheel well inner. Fitted there with a pvc pipe bracket, looks rather neat.
Seeing that we have a long weekend, I'm currently at the in laws and far far away from my landy.

Cheers all, will be chatting later again.

Heinie