The oil burning question

[AliK]

Guys,

I was thinking that if the oil control rings are clogged up, maybe some oil additive or overnight in cylinder soak with Magic Marvel Oil or Sea FoM may do the trick - any thoughts on this? Or any recommendations on oil treatments?

It would be a shed load cheaper than a year down!!!

Thanks,




Ali K

 

[AliK]

I really hate auto correct!!! It should have read Sea Foam and then cheaper than a tear down!!!! Grrrrr!



Ali K

 

[tel240z]

oil control

Guys,

I was thinking that if the oil control rings are clogged up, maybe some oil additive or overnight in cylinder soak with Magic Marvel Oil or Sea FoM may do the trick - any thoughts on this? Or any recommendations on oil treatments?

It would be a shed load cheaper than a year down!!!

Thanks,





Ali K

its worth a try IMO just drain the oil after

 

[SKiddell]

In the majotiy if engines i've opened up, excessive smoke has been down to bore wear and rings, worn valves guides are common (hey most are nearly 40 years old) but stem seals normally mask any issues, and oil generally gets pulled through with high manifold pressures rather than idle.

 

[toopy]

Anyone tried this stuff http://www.ametech.co.uk/

 

[AliK]

Interesting find!!

Not sure I'm yet a believer in potions re-growing worn metal but I'm also open minded to new developments. Lots of contradictory reviews/discussion here ....

http://forums.mg-rover.org/archive/index.php/t-92178.html

Make of it what you will.

Skiddell - what you say makes sense. Strangely the smoke seems to be settling down. Since She goes well and compressions are good, I'm going to put a lot more miles on and re-evaluate.




Ali K

 

[pmac]

Partial rebuilds are always a high risk strategy as you have found out.
They end up being more expensive in the long run than a full rebuild as you repeat a lot of the work to do the rest of the rebuild later and waste gaskets etc.
Looking at your initial post it was clear to me that on a 35 year old 100000 mile smoking and oil burning engine that a full rebuild was the only sensible course of action with a guaranteed result.
Clearly none of the

Dear Z brain trust,

experts thought so.

compressions are good,

I dont agree IMO they are mediocre.

When I asked they said they checked the bores and there was some wear but nothing unusual or too great

Hmmm! An interesting but not very scientific answer.
Each bore should have been measured in two directions at at least four heights. The results (around 50) should then have been cross checked with std dimensions..

If oil is coming out of the crankcase breather does that not point to issues with worn piston rings etc,

Yep.... but everyone just ignored your point.

I have seen on track, two expensive engines blowing oil fumes onto the exhaust and causing smoke.

Which signified they were about to blow up or had been badly but expensively built in the first place.

 

[Rob Gaskin]

Which signified they were about to blow up or had been badly but expensively built in the first place.

Pete, not the case as far as I know. You know one of them.

 

[andrew muir]

Agree with Rob on this one.
One of the best engine builders in Oz with many Bathurst 500 wins to his name builds large clearences into the endurance race engines, they rattle a bit when cold but once they are up to temp run fine they probablly blow a bit of oil but apparently they are more reliable like that and revy, Talking seventies 3.3 straight sixes and 5.0l V8 here.
Do you want that on a road car is the question.

 

[andrew muir]

Heres a link to who I am talking about.
http://www.brock05.com/dreamworks.php
"Tatey" also has built several quick L6 motors which he rates highly.

 

[pmac]

Do you want that on a road car is the question.

I dont for sure and neither does Ali.

I have never been able to see F1 or NASCAR live but watching on TV the only time they smoke is just before they retire.
Likewise Aussie V8 racing

 

[andrew muir]

That is true as stated when up to temp they run fine but they run very large clearances, don't know about F1 but production based engines like Aussie V*s from a few years back run large clearances and rattle like crazy and smoke when cold. When up to temp ok!!

Yes you don't want a smoking car on the road agreed!!
But an oil burning car is not always just about to expire!

 

[z32bolt]

This whole business of race car engines smoking is kind of a mute point I believe, IIRC back to what I was told a while ago the reason they have such large tolerances is because they run hotter. Think of it as an expansion gap, which is why once warm they no longer smoke. I believe some of these engines are actually warmed up and circulated artificially before they are fired up as cold they would run too poorly.

That isn't what you want for a road legal car or even a car which is used for track days, that's serious competitive racing engine stuff.

Happy to be corrected, but this is how I understand it.

 

[SKiddell]

OK Lets be clear on some things here
There is smoking from the engine through the exhaust (burning oil internally) and then there's oil vapour from a missing breather misting onto the exhaust

The two are very different, Rob was referring to my engine when it was on test around Donington 2 years ago which didn't have a breather connected, going into heavy right handers any L series under high rpms with throw a little oil around in the sump which the moving parts will mash up, due to slight crank case pressure, resultant oil vapour will attempt to exit through the breather (that's what its there for dohhhhh) ........normally with a race engine it is captured with a catch tank etc (that's what its there for dohhhhh)....however on that day we were in such a rush to test that this was omitted, the oil mist soaked into the exhaust header wrap and smoked.

I believe Silvain had a similar issue a while ago at Spa (apologies if wrong)

Myth and hypebole seems to account for 99% of the internet these days

 

[AliK]

Pete - It's great when you visit the forum because: 1) I always value your no nonsense and candid advice and 2) it's like the "Z parts Santa" has come to town!

You are very right on the partial builds cost thing - I'm an adult and take full responsibility for my own decisions but I have to admit my decision to rebuild the head first was greatly influenced by a conversation with Fourways. I guess we live and learn.

Being totally frank, the head job cost me 1.5x the quoted worst case and I don't really wish to repeat that experience with the bottom end.

So with that in mind I ask again, is there a mechanic that anyone would recommend for a rebuild who can do a great job without breaking the bank (in the South or elsewhere)?

Ali

 

[Rob Gaskin]

OK Lets be clear on some things here
There is smoking from the engine through the exhaust (burning oil internally) and then there's oil vapour from a missing breather misting onto the exhaust

The two are very different, Rob was referring to my engine when it was on test around Donington 2 years ago which didn't have a breather connected, going into heavy right handers any L series under high rpms with throw a little oil around in the sump which the moving parts will mash up, due to slight crank case pressure, resultant oil vapour will attempt to exit through the breather (that's what its there for dohhhhh) ........normally with a race engine it is captured with a catch tank etc (that's what its there for dohhhhh)....however on that day we were in such a rush to test that this was omitted, the oil mist soaked into the exhaust header wrap and smoked.

I believe Silvain had a similar issue a while ago at Spa (apologies if wrong)

Myth and hypebole seems to account for 99% of the internet these days

Exactly, your engine wasn't about to blow up and neither was Sylvain's 'stroker', both expensive and powerful engines. Both on track (as I mentioned) so extreme circumstances.

My point was that the breather is there for a reason (as you have repeated) and that is to relieve pressure and it needs to be clear and have a pipe on it.

Have a look at this from 2011, especially the latter stages:

https://www.youtube.com/watch?v=ZKemKfn-xTw

 

[AliK]

Ok fellas, have decided on how to proceed with the bottom end rebuild. The only thing is it's realistically not going to happen until end or after August. The only problem is, the MOT runs out on 01-Aug !!

So, has anyone passed an MOT with a smokey engine? Do they even test emissions on a car of this age (1977)?



Ali K

 

[Rob Gaskin]

They should fail it if it smokes a lot, no specific emissions test on cars of that age.

Mine passed when it was burning oil

Still waiting on a reply for you by the way.

 

[AliK]

Thanks Rob! Will try to drain oil before MOT!!



Ali K

 

[AliK]

MOT passed today with no advisories !!!

So now I can put some oil back in the sump!

I was allowed to watch and I spoke with the chap most of the way through the MOT, it's surprising how simple the test is on our Zs and how forgiving they can be on things like a bit of smoke from older cars.

I also took the opportunity to pop into Fourways which was a few miles down the road - the place is very empty without Geoff but they are getting on with business which was good to see.



Ali K