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MG Midget and Sprite Technical - Engine oil loss and HIF44

Hi. I recently did a complete engine overhaul due to oil loss. New pistons, the lot. I am now loosing masses of oil after the rebuild. I was told the new rings will have to bed in but I am talking a pint in a few miles. I have read the many discussions in the archive and learned that oil can be blown out by crankcase pressure. This made me wonder whether the HIF44 I fitted at the same time has anything to do with it. I had difficulty getting the breather to bend round the other side of the carb and the pipe has kinked so I will cure this first. Has anyone else had problems with oil loss following this carb conversion? I also saw on the web a picture which showed the manifold hot water pipes used for vacuum and the old copper pipe retained for the water. looks neat.

W Clough

Hi
As you may have seen in the good news bad news and bad news bad news threads I have been having similar problems.
I have completely rebuilt the engine and fitted an hif44 and seem to be burning oil.
For me it could just be a need to run the engine in but it does seem quite smokey.
Is your engine a rebuild?
Cheers
Tim
T Dafforn

"This made me wonder whether the HIF44 I fitted at the same time has anything to do with it. I had difficulty getting the breather to bend round the other side of the carb and the pipe has kinked so I will cure this first."

The HIF44 won't be the cause. If the pipe is kinked or bent that will restrict suction, and will lessen the chances of it being oil sucked from the crankcase.

As a test. Disconnetc the breather pipe completely. Seal the pipe on the HIF so you don't get an air leak. Leave the timing cocer breather open.

Then drive it and see if you still consume the same amount of oil. If you do, then start looking elsewhere for the cause.
Lawrence Slater

Is it consuming oil (burning / ingesting)
or is it loosing oil - leaking. If the latter can you confirm if it is the rear crankshaft scroll that is leaking, or something else - like a sump gasket leak?

Consuming oil and leaking oil are likely to be almost opposite causes.
Guy W

Tim, my engine was complete rebuild but I am not burning oil just loosing it. It drips heavily from the back of the engine but it had all new seals and Wellseal. I have just now removed the pipe from the carb where it was kinked and blown through it when kinked to the same amount and it was blocked. I have now fitted a pipe which does not kink.
Lawrwence, I wasn't thinking so much about the oil being sucked out. I was thinking more that the crankcase pressure was not being able to vent so pushing oil out under pressure. I will try it now with the new vent pipe and see. I will let you know but I will need a few days before I will give it the all clear
Thanks for all the help up until now
Walter
W Clough

Walter. I have an HIF44 on my car and I have the breather arranged through the water pipe in the manifold, as in your picture. No oil problems so far.
If the pipe was kinked it would allow pressure to force oil past the scroll.
When you rebuilt your engine, did you disturb the "Eyebrow" on the back of the engine. The position of it is critical to the efficient operation of the scroll. With it in the right place, the scroll works as well as it can, which is never brilliant, but if the eyebrow is not aligned properly the scroll doesn't work at all well and will allow oil to get past it, especially under extra pressure.

Bernie.
b higginson

Yeah that's it. Drips heavily from the rear of the engine. But a pint in a few miles seems a large amount. Lets say you mean 4 miles as a few. That seems excessive for the rear scroll to me. Possibly the corks aren't in properly?

I had a crack on the rear of my sump. The flanges that hold the corks had seperated enough to allow oil to leak out in pretty large amounts. But still a pint in 4 miles is a pretty big amount to lose.
Lawrence Slater

Good evening Walter, where did you get a photo of my engine bay from?

This was last year, prior to the LCB and a modified heat shield.

Regards Tony
Tony G

Done 20 odd miles now quite hard driving and no loss. Fingers crossed. I'm still going to check as I am quite nervouis about this after all the problems. I will keep you informed.
Tony, I got the photo by googling HIF44 pipe connections and going to images
Walter
W Clough

Walter

I have a similar arrangement with HIF 44 and can comment as follows.

Initially I too hooked up the crankcase breather to the carb body stub after fitting the HIF 44. I too experienced considerable oil loss at the rear of the crankcase, and my conclusion here was that the carb was not providing enough suction head to remove the crankcase gases. As such, gases build up in the crankcase, over-pressurize the scroll seal, and drip drip drip oil all the while the engine is running. This was evidenced by some lovely patterns on the drive, which whilst instructive in light diffraction in the rain did not endear me to the C in C.

My solution was to refit the PCV to the manifold stub to increase and control the suction head and thus maintain a small suction on the crakcase - thus negating the pressure on the crankcase seal. You may get away with it by connecting the breather directly to the manifold rather than controlling the vacuum head via a PCV, but in so doing you may scavenge oil from the cranckcase, admit oil to the engine and burn it, incurring oil loss that way instead. Clearly any blue smoke is a good indicator!

Personally I would fit a PCV.
Mark O

OK. I can now report that after several sporty local drives of over 20 miles each I have had no further oil loss other than the "normal" A series drip. I have attached photo of present vent pipe set up. Let's hope that's. Thanks again for all the interest. Walter

W Clough

That's a clean looking engine bay. Obviously it needs some driving to make it look "normal" ;).
Lawrence Slater

This thread was discussed between 07/09/2013 and 12/09/2013

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