Model 8 queries

Biscuit · Post by **Biscuit** » Thu Apr 12, 2007 3:34 pm

Firstly, apologies to Matthew for hijacking his topic.

As I had no choice but to ruin the original timing side crankcase in removing a damaged pump shaft, I have obtained a spare set of crankcases. In both cases there is a hole, probably 3/8" - 7/16" drlled just under the camshaft follower spindle, from the camshaft housing in to the oil reservoir. In the original case this is blanked off, in the 'new' timing side half it is not blanked off, that is any overflow from the camshaft housing goes back into the oil reservoir.

Should this be blanked off?

If it should be blanked, how does the camshaft housing drain?

Tolly · Post by **Tolly** » Sat Apr 14, 2007 10:24 pm

I'm sorry to be a little unsure Alan, but I should know. I haven't had my engine dismantled for about 7 years now and the memory is not as good as it was but I am pretty sure the hole you mention is not sealed up, as you say how can the oil drain back into the "sump". I think I would have noticed if it had been plugged. If you cannot find the result to your satisfaction I have a spare engine (assembled) let me know and I could strip this to find out.

Regards

Biscuit · Post by **Biscuit** » Sat Apr 14, 2007 10:36 pm

Thanks Tolly.

You don't have to strip the engine, if you poke your finger in the filler hole you can feel it, it's roughly on a level with the return hole and slightly towards the outside of the engine. A bent piece of wire would make sure.

Thanks again.

Tolly · Post by **Tolly** » Sun Apr 15, 2007 10:03 pm

Alan, I have checked my running engine and my "spare" and in both cases there is only one hole, which is about 5/16" diameter, going into the encased oil tank. Looking at a spare cam housing I have it looks as if the oil drains into the sump via the camshaft bearing and is picked up by the pump and deposited back through the said hole to the encased oil tank, I would imagine the same as the G3 & G80. There is certainly only one hole which is the return.
I hope this helps.

Regards,

Biscuit · Post by **Biscuit** » Mon Apr 16, 2007 12:23 am

So if you run your finger through the filler hole, down the division betwixt the oil reservoir and the camshaft housing, you can't feel a hole, plugged or otherwise?

ajscomboman · Post by **ajscomboman** » Tue Apr 17, 2007 6:29 pm

All this talk off fingers in holes meant that i just had to join in. Alan i've just looked into my filler hole and found it to be the same as your cases. A hole approx 7/16 dia unplugged. I too have always assumed it's a return for oil from the top end.

Merlin · Post by **Merlin** » Tue Apr 17, 2007 8:29 pm

Tut tut the moderator will get you

Biscuit · Post by **Biscuit** » Tue Apr 17, 2007 9:02 pm

Well, last night at club night I touched up a members oil tank and there never was a hole, plugged or otherwise, so I have plugged the one I have.

It runs well and I have actually got oil circulation!

Tolly · Post by **Tolly** » Thu Apr 19, 2007 11:04 am

Sorry I didn't reply before Alan but I am away from home at the moment and just found a computer.

As you have found out by another members casing there is only one hole, a return hole. Thinking on this, is the other hole a mod. for later engines because, theoretically it does not matter how the oil drains back as long as it does. The extra hole may aid oil to return more quickly but I can't answer why.

Anyway I'm glad you have got it running o.k. with a good oil return, they're not a bad little engine once you get to know them.

Regards, Tolly

Biscuit · Post by **Biscuit** » Thu Apr 19, 2007 11:39 am

Thanks Tolly, I only met a lightweight 15 days ago, but I feel like an expert already, pride before a fall?

I'll have to post a pic of the oil pump shaft, it could be a salutary lesson!