Smokin' Joe Frazier - Burning oil

[carbon]

Same question as JCT One - are there valve stem seals fitted on the exhaust valves?

[Benny]

Same question as JCT One - are there valve stem seals fitted on the exhaust valves?

It does not appear so from what I can tell, but this is pretty typical from what I understand, as the exhaust guides don't see a vacuum like the intakes do.

[Benny]

Benny
On your rocker pillar that feeds the oil up the pedestal you should have (unless they changed it) a different top with a slot in ,the slot holds a threaded screw that restricts or controls the amount of oil entering the rocker shaft.

On the 1275, the oil feed comes up the #1 pedestal, but the treaded fitting is in the #2 pedestal, so I'm not understanding how that could be used to meter oil flow. I always understood that fitting was just to locate the shaft, and orient it properly?

[graham in aus]

On the 1275, the oil feed comes up the #1 pedestal, but the treaded fitting is in the #2 pedestal, so I'm not understanding how that could be used to meter oil flow. I always understood that fitting was just to locate the shaft, and orient it properly?

Benny, I agree, I was just typing something similar. The screw is a locator, it has a tapered 'nose' and this locates in a countersunk hole in the shaft, should be screwed in till snug / lines up with slot in locating plate on top of pedestal.

Cheers

[carbon]

Benny,

My best guess is that you have oil getting down the exhaust valve guides, if you don't have any seals fitted here. Not really a problem apart from the blue haze... and slightly higher oil consumption.

You would think that with the higher pressure in the exhaust that the oil would not be able to get down the exhaust guide, but I have done decokes on 1275 heads without them fitted and there has been a whole load of black carbon just on the back of the exhaust valves which I suspect is from the oil getting down the guides.

[Frogeye61]

Excuse me for interfering, but though I don't disagree with the possibility of oil entering through the exhaust guides and causing smoke, I will say it is rather difficult in such a manner for the oil to enter the inlet manifold. Maybe the "oil" in the inlet manifold is the remains of evaporated fuel. This would be more plausible if the fuel actually contains oil, like as retrieved from the petrol tank.
Just a thought.
Donn.

[In the shed]

Breather.

Unplug that straight away.

[minimans]

I rather think it's fuel in the inlet tinged with oil, is it possible you have a float set too high? causing excess fuel at idle? this will wash the bores of oil and then burn when you blip the throttle? at higher RPM the mixture stabilizes and burns "clean"

[Benny]

Breather. Unplug that straight away.

Please read previous posts....I've answered that one already.

I rather think it's fuel in the inlet tinged with oil, is it possible you have a float set too high? causing excess fuel at idle? this will wash the bores of oil and then burn when you blip the throttle? at higher RPM the mixture stabilizes and burns "clean"

A quick update on this one...I took it for a 12-15 mile freeway drive today, and the problem seems to be getting worse. After a long, downhill freeway run, I pulled off, and allowed it to idle for about 20-30 seconds. Then I blipped the throttle, and sent out a (bright blue) smoke signal that could have probably been seen from outer-space It also now seems to be smoking more at idle than it was before.

I pulled back onto the freeway, and the smoke cleared very quickly....drove home, and let it idle in the driveway for a bit (still smoky). I pulled the plugs an they all looked very nice, and not oily at all. I pulled the intake manifold, and this time, it was totally clean and dry. The intake runners on the head were also quite dry and clean this time. I'm thinking the oil in the intake the first time around was excessive dashpot oil, and that it was acting as a red herring for the REAL issue, which lies somewhere else. I'm going to call the machine shop on Monday before I pull the head.

[ianh1968]

What is the manifold?

I had a similar problem for a very long time...

In the end I deduced that the ports in the manifold were way too big
and the port velocity was too low. This causes the fuel to "puddle" in the
manifold as you have described. On my engine, the "oil" was actually a
combination of unburned fuel and exhaust deposits caused by the overlap
on the cam.

The "puff of smoke" was, I believe, caused when the level of collected
goo in the manifold was high enough that it could flow neat as fluid straight
through the port in the head. This would burn off, and afterwards the engine
would run clean again.

The manifold was replaced with an old Howley that had much smaller
port-runners, thus greatly increasing the port velocity - This immediately
gave me a huge increase in low down torque and cured the "oil" problem.

Many manifolds are sold on high flow figures, which in some cases is achieved
by having overly large ports. I fell into this trap and it took me over twenty
years to realise my mistake...



Ian

[AustinSuperSeven]

I would go with guides a bit low and no seals on the exhaust valves!
Sounds like oil is sitting in the valve recess, and no doubt an efficient oil pump has been fitted which is getting plenty of oil to the head and finding its way down the exhaust valve.
Going for a long run is burning it off, but once you stop the excess oil is pooling around the top of the valve stems and causing blue smoke on blipping.
Has a high pressure oil pump been fitted and over oiling the the rocker and head area? Meaning oil is not draining away down the oil ways quick enough and over oiling the head area?
I'm rambling now ......seeya!
Hope you get it sorted!

[Benny]

is it possible you have a float set too high? causing excess fuel at idle?

This is a possibility, but would you not expect to see other "flooding" symptoms? The carb came off a running Bugeye, so would have been sitting in a more level orientation in its previous life. I must admit some ignorance on the HIF, as this is my first exposure to one. Is there a tried and tested procedure for setting the float level for a Mini at a fairly "conservative" level?

What is the manifold?

Just a MiniSpares job....nothing radical. This one is about 12 years old, and I understand they have changed the design slightly since then, but I think it was more to change the angle of the carb than the size of the runners.

Has a high pressure oil pump been fitted and over oiling the the rocker and head area?

Just a standard pump with a standard pressure relief valve. Runs at about 70 psi, and is idling around 50 psi.

[minimans]

If it is valve guides you should be able to run on the freeway or suitable street at higher revs and back off the throttle for a period then accelerate away leaving a nice blue cloud behind you! If no cloud I'm inclined to not think it's guides.
To set the float level on a HIF you really need it off the car and turned upside down and remove the base plate then with a straight edge across the base flange you should have a set gap to the lowest part of the float. I usually set mine at .5mm to a .75mm gap but if your float protudes above the base flange you definatly too low and more than a 1mm too high

[wantafaster1]

What about fuel pressure too high rather than wrong float height?

[ianh1968]

What is the manifold?

Just a MiniSpares job....nothing radical. This one is about 12 years old,
and I understand they have changed the design slightly since then,
but I think it was more to change the angle of the carb than the size of the runners.

This was exactly my problem, but I did not want to say this in case Rich was listening...

The manifold I took off was also a MiniSpares job, the large bore version, they used
to list two....

It appears more recently that they only list one "size" and I am wondering if this
was in part at least to do with the size of the port runners. And yes, the angle
was a problem: I had the carb face on mine machined slightly tapered to give me
more bulkhead clearance for the air filter.

[Benny]

I usually set mine at .5mm to a .75mm gap but if your float protudes above the base flange you definatly too low and more than a 1mm too high

Thanks. The carb is off at the moment, so I'll have a check.

What about fuel pressure too high rather than wrong float height?

Fuel pump is the little, square Facet. I purchased it from Moss Motors for my MGB, and if I remember correctly, they list this one at 5 psi. I'll measure it to see what it's actually putting out.

[ianh1968]

they list this one at 5 psi.
I'll measure it to see what it's actually putting out.

SU's are supposed to run with only about a 2.5PSI feed, but, if the fuel
feed needle valve is good and seals off OK it really should not make
much difference.

Where it would make a difference would be on bumpy terrain where
float bounce would cause a violent influx of fuel. At idle or on a smooth
road, running slightly too much fuel pressure should be of little consequence.

Ian

[Benny]

..... and turned upside down and remove the base plate then with a straight edge across the base flange you should have a set gap to the lowest part of the float. I usually set mine at .5mm to a .75mm gap but if your float protudes above the base flange you definatly too low and more than a 1mm too high

OK, we may be onto something here with the fueling. I just want to make sure we are using common terminology when you say "lowest part of the float". I found this video on setting the float level by John Twist, who is considered a GOD by a lot of MGB guys. I've personally often found his information to be somewhat questionable, but he says the float level should be checked at the center of the "scoop" in the float. If Twist is correct, then my float was set way too high....and I mean WAAAY too high.

http://www.youtube.com/watch?v=vPCfwkIdWpc

Also, I measured the fuel pressure that I'm getting from my little Facet, and it's 5.5 psi. I've just done some quick research on-line, and it tends to agree with Ian's comments that 3 psi is more in line with the maximum I should have, and 5 psi is pushing your luck. I had two Facets on the shelf...one for my MGB, and one for my V8 Cortina, and it's entirely possible I grabbed the wrong one.

If the float level was as high as I think it was, and the fuel pressure was nearly double what it should have been, then we could definitely be onto something here....

[minimans]

Yes as per the video, I've seen this guys videos before and hes pretty good but some of the methods used are a bit "different" but it gets the job done!! Definatly you need to use the correct pressure for the carb as per the previous post it's the banging around of the float that will cause problems.

Ever thought about putting the correct SU pump back on....................................

[Benny]

Ever thought about putting the correct SU pump back on....................................

I've thought about it, but I don't feel the current ones are as good as the originals, so it would have entailed finding an original, then having it refurbished.

I've always been happy with the little Facets, as long as they are spec'd correctly....it now seems obvious I had the wrong model on this car.