Pressure Fed Conversion

[Chris KC]

I'm pretty certain the original threads were BSP, but where people have been tinkering there's no telling!

[Charles P]

OK. Good points. Will go with "serious" strength loctite.

On this engine I haven an external oil pressure valve so with the gallery as normal full pressure oil will be flooding the cam bearing and timing case if I don't block it off.

Charles

[dickie65]

Hi Charles,
Vintage engine rather than PVT I take it. Mag engine ?
I suspect your build is like my current engine 1934.
It is still worth putting a metering orfice into the camshaft feed and either making a new bearing without the oil groove or tinning it and filling it with solder, oil will still find its way to the cam drive gears. 
I have made a brass reducing bush which is an interference fit it has a 1.5 mm drilling for the oil feed to the camshaft.
If you look inside the camshaft bearing housing on a lot of crankcases you will see where the oil has scoured the alloy away from the oil feed drilling.

The external O rings stop oil from going round the outside of the camshaft bearing ( I suspect you will still have oil at about 60 to 80 PSI )
What feed are you using to the crankshaft nose ?
Brass bush type or lip seal type ?
The brass bush type will help feed oil to the timing cover and lubricate the gears.

[stuartu]

Quote:
"It is still worth putting a metering orfice into the camshaft feed and either making a new bearing without the oil groove or tinning it and filling it with solder, oil will still find its way to the cam drive gears"

Charles, I presume this is for a blown engine? I think you will be aware that eliminating the oil groove when an Ulster type gear driven supercharger is loading up the system will result in rapid wear of the timing gears accompanied by an impressive scream from the mechanism at circa 3000 rpm. I speak from experience - although I was not the one who restricted the feed, I just didn't know about it......I mention this in case others with gear driven blowers are tempted.

Regards,
Stuart

[dickie65]

Valid point Stuart.

I do not have a supercharger on the Type 65 Engine.
I had low oil pressure on my engine till I did the mod on the camshaft bearing.( oil was just escaping into the timing gears via the large groove )
I suspect a reduced size oil groove might be a good compromise. or even an oilway drilled into the bush running from the front to the cross drilled oil hole.

I have seen an oil feed directly to the timing gears on one engine. ( not sure if it was Mag or Coil though )

I hope an expert on pressure fed Blown Mag engines will help out here.

The oil pressure bypass could be fed into the timing gear case which would should help the loaded gears as well.

Cheers Richard

[jansens]

On mine the holes in the front and end of the oil gallery were BSPP (parallel) threads. BSP (tapered) fittings wouldn't screw in far I found. I had to source BSPP fittings and use fibre washers under them. I also use Loctite pipe thread sealer which comes in a sort of gluestick type package. I try to avoid the PTFE tape in case any of it strips off and clogs the oil ways.

Simon

[Charles P]

Answers in no particular order:

Yes, a blown engine based on a converted mag crankcase.

The crank is fed through a nose casting with lip seals (a very easy mod on a mag engine)

The extra oil feed to the cam gear was for a coil engine as I recall and had a pipe dripping/squirting oil directly onto the cam gear through the little pressed steel "hatch".

Yes Stuart, I'd rather have oil swilling around than brass & steel filings. However the current arrangement gives unrestricted pressure from the gear pump to the cam bearing at all times, since the PRV is remote. I'll keep the groove and feed the same but add the O rings.

I'll feed the front gallery from the output side of the remote oil filter to give filtered, pressure controlled oil.

Charles

[Chris KC]

I can confirm a 1/16" - 3/32" feed in the front and rear camshaft bushes works fine on a pressure fed engine.

The centre camshaft bush on my 3-bearing engine is drip fed from the valve chest above, this again is perfectly adequate.

Charles, I'd question the need for 'serious' Loctite, you'll regret it if you ever want to get the thing out. As noted above, as long as the outlet elbow sticks even slightly into the gallery the plug physically cannot come out. It could potentially weep oil past the plug but no particle of significant size can pass through. It needs a dab of thread sealant at most.

[squeak]

I am raising this old thread as it contains a lot of good advice. We are converting a 3 bearing engine to 2 bearing pressure feed and have machined out the centre bearing housing.
We have an over bored Austin oil pump delivering through the standard 5/16" hole to the lower oil gallery. The standard relief valve is blocked off and oil flows up to a remote full flow oil filter with an adjustable pressure release bypass. This overflow will reenter the crankcase via the filler tube or the plate over the timing gear.
Camshaft is O ringed and 3/32" restrictors in place, the cam centre plain bearing will be pressure fed through 1/16" jet.

My question is as the oil supply at the pump is only 5/16" ID, is there any point in making the other fittings in the system any larger?
I see 1/4" BSP has been mentioned , what size internal diameter is this ?
Guidance will be appreciated   Russell

[Terrytuned]

Charles articale on pressure feed abit out of date as I did it some years ago, scroll down for pt2, also photos of new oil feed position avoiding bottom hose but feeding to cam and nose. You need to tap deeper through the front of the gallery past the new position and blank off with 1/4 bsp blank plug locktited in place same as rear end of gallery. The rear feed from the enlarged oil pressure outlet feeds the oil filter and outlet from fiter feeds back into the front of the gallery. Terry.

---

   
Charles you can see the oil feed setup on these photos of a finished engine. Terry