Author Topic: 1/3rd scale V10  (Read 219221 times)

Offline keith5700

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Re: 1/3rd scale V10
« Reply #180 on: August 20, 2015, 10:04:18 PM »
Mike, the ptfe sheet is 0,25 thick. It seems pretty tough so I'm hoping it will be ok. Theoretically there should be very little rubbing going on.
The driving shaft is 5mm dia. And the gears are 1/2" od.
The shaft for the idler gears is ground tungsten carbide, which I just happened to have lying about.
This creates a superb low friction bearing surface.
I have yet to test the pump, hopefully it will all be fine. Cheers.

Online Vixen

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Re: 1/3rd scale V10
« Reply #181 on: August 21, 2015, 10:43:12 AM »
Keith,
Thanks for all that information and advice. The pressure and scavenge pumps on the Mercedes are all 15mm OD and the shafts are 6mm OD, so things will be a little larger and easier for me. I am still a long way off starting to build the pumps, I am still at the drawing stage.
The full size Mercedes engine had hard metal plates separating the various pump sections, the pump gears rubbed against these hard metal plates. With three pressure and four scavenge pumps in the block and all those separation plates, there are many, many gasket faces; all of which will want to leak. I am looking to see if I can incorporate your idea of a combined ptfe gasket and gear rubbing surface. It may help simplify things.
There is a lot to be said for a freelance design compared to slavishly building to scale.

Cheers

Mike
It is the journey that matters, not the destination

Offline keith5700

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Re: 1/3rd scale V10
« Reply #182 on: August 25, 2015, 01:07:21 PM »
well, the oil pump project has gone off the rails a bit.
I anodised the front bearing housing, and this came out brilliant.
then I did the 3 gear housings, all at the same time. I noticed they seemed to be fizzing a bit, in the anodising tank, but thought no more of it.
Then when I dyed them, and sealed them, they looked awful.
Sometimes I get this, if I've used free cutting ally for instance.
Anyway, I decided to assemble the pump for testing, and sort the anodising out later. When I assembled the pump, with the ptfe gaskets, it looked even worse.
The pump now looks like some item of confectionery, rather than an engine part. It'll have to be plain silver I think.








Offline Roger B

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Re: 1/3rd scale V10
« Reply #183 on: August 25, 2015, 01:36:15 PM »
As you say that's a rather strange finish  ::) At least you should be able to test the pump system with it. There seems to be quite a large clearance between the gears and the body or is it just the angle of the picture? I thought that gear pumps had to have a close fit? (I am currently designing/starting to build one as a water pump for my horizontal engine)
Best regards

Roger

Offline keith5700

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Re: 1/3rd scale V10
« Reply #184 on: August 25, 2015, 02:34:40 PM »
Roger, they are a lot closer than the photo. I've put a bit of a radius on the ends of the teeth to prevent any digging in on the ptfe.
There's probably around 2-3 thou' clearance.
Cheers.

Offline fumopuc

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Re: 1/3rd scale V10
« Reply #185 on: August 25, 2015, 06:57:56 PM »
Hi Keith, I think the colour will be no real problem. The pump looks fine and more important will be the function. Waiting for the result of your sealing concept. In modern high performance engines, there are usually the gears running against the aluminium housing of the next chamber (pump housing) and the sealing is done by a grove and an o-ring.
Kind Regards
Achim

Offline cfellows

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Re: 1/3rd scale V10
« Reply #186 on: August 26, 2015, 03:00:26 PM »
Stunning work, Keith! 

Chuck
So many projects, so little time...

Offline MrDude_1

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Re: 1/3rd scale V10
« Reply #187 on: September 03, 2015, 08:02:20 PM »



actually, that looks like what real "red" pumps look like after several seasons... they fade out funny.

Offline keith5700

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Re: 1/3rd scale V10
« Reply #188 on: November 02, 2015, 12:47:12 PM »
well, things seem to have slowed a bit. I seem to have been messing around with this oil pump for ages. However, it's finally finished and working. I changed the colour in the end and it doesn't look too bad now.
Going to get back on the supercharger now. See if I can get any useful pressure out of it.






Offline BillTodd

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Re: 1/3rd scale V10
« Reply #189 on: November 02, 2015, 04:10:14 PM »
Mindbogglingly good  :NotWorthy: :NotWorthy:

Bill
Bill
wy omnibus Latinis taurus stercore?

Offline Greg Haisley

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Re: 1/3rd scale V10
« Reply #190 on: December 09, 2015, 05:21:05 PM »
Keith,

Visited Dyers Blowers a USA company in Chicago that does nothing but make blowers for the industry. 4-71, 6-71 and 8-71 GMC style blowers.

Some information I got from these guys. They run tip to tip clearance at .007 - .008 inch clearance also tip to case at the same clearance.

The tip to tip is set by shimming the helical gear on the driven rotor forwards or backwards to clock the rotor independently from the driving rotor. The helical gear slides on a splined shaft inserted and pinned to the rotor. This is why they can set the tip to tip clearance. The other thing they said is obvious you can not have aluminum touching aluminum. Or it will weld. So the rotor profile may need some clearance work to help eliminate this. The rotors really act like fan blades pushing the air to a confined space creating the pressure.

To get the tip to clearance they move case bores up and towards each other. He said you are only creating pressure on the bottom of the case from 3 o'clock to 9 o'clock, the top is just clearance. He also said the rotors under pressure will try to bend up towards the top of the case.

I hope this info doesn't throw up a road block for you, but rather help you to finish up your engine.
Cheers,
Greg Haisley

Offline keith5700

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Re: 1/3rd scale V10
« Reply #191 on: January 06, 2016, 01:10:20 PM »
Thanks Greg, sorry I've only just noticed your reply for some reason.
I decided to park the supercharger for a while and get everything in place for a Christmas fire-up.
This would be with a simple carb, no fuel injection.
All I wanted was to test the engine mechanicals, oil pump, spark plugs and the Megasquirt, for its 10 sequential spark output.

I finished the spark plugs first. They had 15mm of Macor insulator in the nose, and then the rest was ptfe. the electrode was 1mm copper wire. Then I made a simple insert for the inlet manifold, to direct air and fuel into the inlets.

I managed to get the Megasquirt wired up and programmed, and connected to the 10x coils, which came off Toyota Yaris.
The sparks firstly came out as wasted sparks, ie firing in pairs, but after adding the hall effect sensor on the camshaft, they came out singly, and in the correct order.

this is Megasquirt 3 with about 60 wires attached



These are the coil packs





20-50 full synthetic oil aerating from scavenge pumps



Part of the cooling system, in the vee of the block



Crappy inlet manifold insert.




Offline keith5700

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Re: 1/3rd scale V10
« Reply #192 on: January 06, 2016, 01:24:58 PM »
this is the test bench setup.



Basically the engine ran like a dog. I managed to get it running on 7 cylinders before I gave up.
There was obviously a problem with the spark plugs, like I had with the V8.
I made another pressure chamber so I could test fire the plugs under pressure, up to 90psi.
This showed that some of the plugs were leaking to earth before getting up to 90psi.

To cut a long ball-ache story short, it turns out that this machineable ceramic isn't that insulating after all.
once the plugs get under a bit of pressure the spark takes an easier route, which, dissapointingly, was through the side of the insulators.

That turned out to be a load of work down the pan.
I quickly remade the plug internals with one length of ptfe rod, with tungsten carbide electrodes, and fired it up last night.
It ran smooth as anything, and idled quite low too.
Still smokes a lot though, so the 3rd ring hasn't helped much.
Confidence restored, I can now carry on.



Offline Roger B

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Re: 1/3rd scale V10
« Reply #193 on: January 06, 2016, 02:38:09 PM »
Great progress  :ThumbsUp:  :ThumbsUp: and always something new to learn  ::)  :headscratch: Do you have a video of the first start/run?
Best regards

Roger

Offline gbritnell

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Re: 1/3rd scale V10
« Reply #194 on: January 06, 2016, 02:39:59 PM »
Keith,
I tried to start my flathead engine several weeks ago and got a lot of oil into the combustion chambers. If you have read my thread I had made provisions for oil rings but my original design didn't work so I tried to run the engine with just compression rings. I went back and came up with a different style of oil ring and was able to mount them on the pistons fairly easily. When I ran the engine over in the lathe to check things out (without the heads on) I was still getting a little oil past the rings. Not as bad as before but enough to make the engine smoke if I tried to run it. I have made a third rework of the oil rings so I'll have to see how they do.
My 302 V-8 has 2 compression and 1 oil ring and it has never smoked from day one so I'm perplexed as to to what's going on.
I don't know if there's words enough left to describe your engine but as far as a miniature it's totally incredible. Your attention to detail is mind blowing!
gbritnell
Talent unshared is talent wasted.