Sump oil way diameter comparison

This may be of interest to some of you.

Having recently bought a new sump for the T3 and having a few others hanging around I decided to measure the oil way diameters after reading a posting on a US site about G&G sumps.
I checked the oil ways using the chuck end of decent quality drills (no burrs). If a 9.5 mm didn’t fit and a 9.0 did it’s listed as 9.0.

I had the following : standard 1980 T3 sump, standard 2002 cali SS, Stein Dinse external oil filter (V-shape) , brand new G&G external filter (since returned to the retailer).

All holes were measured at the ‘top’ holes in the sump. Dimensions in mm.

Oilway______________T3__2002 Cali__V type__G&G
Input from oil strainer___9.0___10.5____10.0_____7.5 Oil pump pick-up.
Middle to oil filter______ 8.0____8.0_____8.0_____7.5 Oil pump output
Outer to oil filter_______8.0____8.5_____8.0_____7.5 Front main and cam feed.
Pressure release valve__8.0___8.5_____8.0_____7.5 Rear main and cam feed.

(apologies for the mess but I can’t get it to submit with multiple spaces)

V-type is perfectly OK for a T3 and marginal for a Cali 1100.

G&G is of no use to any as the oil ways are too small. This represents a massive loss of oil feed - the areas for the oil pump pick up are 63.6 mm^2 for the T3 and 86.0 mm^2 for the Cali. The G&G only has 44.2 mm^2.

The G&G has more issues as well. There is no proper location for the oil strainer on the oil pump feed tunnel. The standard has 2 ridges, the V type one and G&G none.
The V-type is acceptable as it is correctly located and provides a seal against large lumps of metal going into the oil pump. There is a considerable gap with the G&G.

The G&G sump I had was re-machined by HMB so a standard pressure relief valve would fit correctly. I asked them why this was so and they replied that although they had contacted the manufacturer many times about the sumps’ faults they wouldn’t change anything.
Since the manufacturer is another German MG parts supplier this could be sour grapes. Gutsibits sell the same sump without mods.

I have also had a ‘high quality German engineered’ aluminium billet oil pump, probably from the same manufacturer. This was sub-standard also - there was a ridge on the base which should have been perfectly flat and burrs all over the place. HMB actually withdrew that particular item from sale over quality issues.

Interesting - can you post a link to the US discussion, please? More info needed!

Struggling to think what earthly difference .5 mm smaller can make.

BTW on mobile fone view the above table bleeds off right hand edge so can’t see all of
the last numbers. (But I saw them earlier on the PC.)

OK - I’ve just had a look at this. I was concerned as I’ve bought a G&G sump from Gutsibits and it’s the last piece I needed to look at before starting to rebuild my engine - I had assumed it would just be a straight fit without needing any work. Conclusions:

The only gap around the oil pickup strainer which is of real concern is that around the recess for the pickup tunnel - the base of the strainer leaves only a tiny gap. Mind you, the double ridges on the standard sump aren’t that good for a fit, anyway… I’ve used high temperature oilproof silicone to make a seal here, and everything looks all OK. The poor quality component actually looks like the MG original bit…

The oil pressure relief valve does not fit as standard (too wide), so Michael Behrendt is right - the space beside the filter housing is machined for this, but not enough. I’ve opened mine out with a sanding drum on a Dremel - not difficult, but an irritation on something which costs this much.

I’ve measured the oilways with a small bore gauge and a micrometer. Standard Guzzi (Convert in this case) sump oilways are inconsistent width, and widen towards the top flange. Whilst the pickup is 9.6mm wide at the top it narrows to 9mm lower down, but at the strainer outlet it is only 8.2mm - G&G sump is 8.7mm wide consistently right through. All other oilways on the standard sump are 8.22mm at the top flange, but narrow to 7.65mm lower down - G&G sump ones are consistently 7.55mm. I’m not too concerned about this for normal touring use.

My conclusion is that the G&G sump is a good quality piece of kit let down by some small details. Once these are put right I reckon it’s a pretty good item for normal road use, but if you’re planning on high-performance mods of any kind (particularly the uprated oil pump), it’s probably not suitable without significant modification.

Please feel free to tell me what I’ve got wrong, though…

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Thanks for taking the time to measure it properly.
I could only measure at the top holes and assumed they were drilled consistently - obviously not.
With that in mind, I agree with your conclusions.

I only started to look closely after I’d read a posting in the USA but cannot find link again despite looking for it.