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Query on engine cover

Posted: Wed Mar 09, 2016 1:03 pm
by jhon
Hi all - wonder if you can help regarding the engine cover in the photo; this is the one that was fitted to the Haflinger when I bought it and the engine runs fine with it - doesn't seem to get too hot even when idling for a while.

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(Apologies for the photo quality, but you can quite clearly see the rounded profile).

However, I have seen different shape ones fitted to other vehicles; on the left-hand side, like this one that I have picked up from the web..

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So... any advantages/disadvantages of one over the other? My Haf is a 1974 model if that helps.

Thanks!

Re: Query on engine cover

Posted: Wed Mar 09, 2016 2:39 pm
by Julian B
Not 100% sure, but perhaps your 2nd image is when the more ducted tin shrouding is in place for the oil cooler? See two versions of the parts book page below.

Re: Query on engine cover

Posted: Wed Mar 09, 2016 4:15 pm
by jhon
Hi Julian - thanks for the info/diagrams; what you say makes sense - however my engine does have an oil cooler fitted (i.e. the standard vertical one under the cover.)

My concern is - is there a risk that I might not be cooling the engine to its optimum with the current rounded engine cover fitted? (though it doesn't appear that way).

Does anyone know when the changeover in covers happened (or the reasons why)?

Re: Query on engine cover

Posted: Wed Mar 09, 2016 4:46 pm
by Goatwerks
The larger ducted cover houses a larger cooler and has a outlet flap to adjust/restrict cooling airflow.

Re: Query on engine cover

Posted: Thu Mar 10, 2016 1:50 am
by AustHaflinger
If you were in Australia you would cook your engine with that cover - we are now well into Autumn and still have 35°c every day.

I have the cover that allows air through the oil cooler and then exhausts out the back - the air temp is always high at that exit port is always high.

However if at least some air is being diverted through the oil cooler than then down over the cylinder fins and out the bottom (or to the cabin heater, heat exchanger) thenI would have thought that you would be fine in most temps that you get up your way.

Garry

Re: Query on engine cover

Posted: Thu Mar 10, 2016 7:47 am
by heinkeljb
The biggest problem you have is whether you consider the designer of the engine got his figures correct. The left hand cylinder needs a certain amount of cooling air. This is provided by the fan on the Dynastart. That much is obvious.
Now put the oil cooler in the air flow and you have A) a restriction to that air flow, and B) another heat source adding heat to the air that should be cooling the lefthand cylinder.

Now from my understanding of things there are two different oil coolers and two different shrouds. My understanding is that the smaller of the oil coolers (MK1) should be paired with the cooling shroud you currently have on your engine. If you have the larger oil cooler (MK2) then you should have the other cooling shroud with the air diverter elbow on it.

As you state your engine is 1974 - puts it as being one of the last engine I would assume it would have the bigger oil cooler and should have the other cooling shroud with the air diverter. Mine is 1973 and has this combination.

It is of course possible yours has had some work done on it and oil cooler changed....

There is another solution - remove the existing oil cooler, put a plate on which allows the oil to be piped to a remote oil cooler which would remove the restriction in the air flow tothe left hand cylinder.

One of the things you could also do would be to fit a cylinder head temperature sensor to both heads and compare the temperatures.

John

Re: Query on engine cover

Posted: Thu Mar 10, 2016 10:56 am
by jhon
Aaah..interesting...thanks all.

I've been researching and found these illustrations on the web; if these diagrams are accurate it looks like I have the short oil-cooler fitted, which is odd - I think I need to do some more investigation in to the history of my engine.
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I didn't know that the exit at the LH corner was used to vent hot air out of the cowling, but it makes sense. Then again, if that LH corner is vented would that not reduce the air pressure and volume of air being forced down through the head and out past the exhaust ports, thereby potentially reducing the cooling on that LH cylinder?

But, you have to assume that the designers knew what they were doing.

Maybe I'm overthinking it and looking for an issue where there isn't one; if it ain't broke then don't fix it! etc. lol