Marina 1275 big end play

[chesney]

I have a Marina/Ital A+ 1275 I'm planning on fitting to my Minor, it came out of a running car (apparently).
I've taken the sump off as a formality, and have found that the end float on all 4 big ends seems excessive, that is they can be moved along the journal by maybe 1-2mm, by the same amount on each rod.
The fact that they are all the same puzzles me, it just doesn't seem right, though I've worked only on 948-1098's to this point.
There is no up/down play in the big ends, the bearings seem good. Plus I can't see new bearings having any gain on this type of play. It seems almost as if they're meant to have thrust washers, though I can't see how they would fit!
So, is that end float acceptable on these engines (which seems doubtful)?

[bmcecosse]

I wouldn't worry about it - but you should take the caps off and inspect the journals and the shells........ And at least the centre main........

[philthehill]

The 1-2mm sideways movement of the connecting rod big end on a 1275cc Marina A+ engine crankshaft connecting rod journal is normal.
As advised by bmc you should check the main, connecting rod and thrust bearings as a matter of course.
The end float of the crankshaft should be in the region of 0.003" - 0.004". When the centre main bearing cap is off you can examine the thrust washers for wear. If you do not have a dial gauge to check specifics lever the crankshaft forwards or rearwards and with a feeler gauge check the clearance between the other thrust washer and the thrust face of the crankshaft. So long as the crankshaft revolves freely you should be ok.
The 1275cc Marina A+ crankshaft is not the best of crankshafts and whilst reliable for normal duty - any tuning of the engine will reduce the reliability of the crankshaft. To overcome the deficiencies in the Marina crankshaft you can with a straight swop fit the 1275cc Midget crankshaft/flywheel/clutch assy and rear engine plate.
I have a 1275cc Marina A+ block fitted with a 1275cc MG Midget crankshaft fitted in my Minor so can speak from experience regarding the use of the 1275cc Marina A+ engine in a Minor.

[chesney]

Thanks both, if it's a pass, looks like it'll just receive the customary bearing change.
Not looking to tune it, in fact for the interim it'll have to do with an HS4 on a standard Minor exhaust until funds allow.
Onto the next challenge - flywheel!

[bmcecosse]

Take the chance to upgrade the cam while the engine is out - some of these Marina engines have very 'flat' cams - and it's not so easy to change once the engine is installed.

[philthehill]

If you fit a new cam it is good practice to fit new cam followers or if using a S/H cam with its cam followers use the same cam follower on the same cam lobe. Using old cam followers on a new cam can lead to accelerated wear of the cam lobe. Using new cam followers on a S/H cam is acceptable. Using S/H cam followers on a S/H cam that have not been run together previously is folly and unnecessarily risks damaging the cam.

[chesney]

It'll have to have the cam it's got for the time being, we're on a tight schedule, has to be in France in May!
The cam followers look o be in very good condition, and are still in the block so have not been mismatched. It'll be getting a new oil pump, are 'spider drive' pumps difficult to find?

[philthehill]

Spider drive oil pumps Pt No: GLP141 are available from Mini Spares @ £15.83 inc VAT and other good 'A' series parts suppliers.
Do not loose the spider drive adapter Pt No: CHM108 as it is now obsolete and no longer available but you may be able to find a S/H one at a pinch.

[win]

Hi all
Years ago, we used to be able to buy high output oil pumps, to help slightly worn engine bearings.
Not sure if this was a con, they always managed to charged extra for them.
Roy will proberly know.

Regards Win

[chesney]

Thanks Phil, I'd read they were difficult to get hold of but must have been referring to the adapter you mention.

[bmcecosse]

The 'spider' is difficult (= expensive) to find - and it makes it impossible to change the cam without taking the engine out. It must be a very old engine to have that oil pump! Years ago oil pumps were only 3 lobe affairs (that was a big improvement on the early 'vane' type pump...) and so yes the newer 5 lobe pumps were seen as being better......but could never hope to rescue worn bearings , for which there is only one cure......

[philthehill]

The oil pump to have years ago was the Cooper 'S' one, either Pt No: AEG178 or AEG410, both pin drive. More oil flow but not much else. To fit to a 948cc engine you could either shorten the drive shaft or swop the drive shaft with that of a Minor oil pump (I have done both). There is now a spacer available Pt No: 12G1127 to allow the 1275cc oil pump to be fitted into a 948cc Minor engine.
All 'A' Series oil pumps are now the equivalent of the Cooper 'S' one as regards capacity except those fitted to the MG Metro Turbo and ERA Mini Turbo and disregarding those fitted to automatic 'A' series Minis.
The best pump to fit these days to a manual 'A' Series of what ever capacity is the MG Metro Turbo one PT No: GLP110.

[chesney]

Sorry to resurrect, but the part number Phil mentioned for a pump is a '2 bolt' version. The pump that came out used 4 bolts.
Are 4 bolt pumps available, or will I have to use a 2 bolt with some different lock tab arrangement?

[bmcecosse]

There are two/three/four bolt pumps. Just use what you have - with an anti-vibration washer under the bolt heads. The unused screw holes may be better to be plugged...check where they go!

[philthehill]

Chesney
The 4 bolt fixing indicates that you have a Concentric oil pump.
The Hobourn - Eaton oil pump has only a 2 bolt fixing.
Spider drive pumps come either in 2 or 4 bolt fixing.
Whether they are 2 or 4 bolt fixing they are still given the same part number GLP141.
It appears than you can still get either 2 or 4 bolt fixing but you have to ask for the specific fixing you want when ordering.
To change from 4 to 2 bolt fixing you may have to drill extra holes though one hole may line up. It is easy to drill out and tap the required hole. No need to no deeper than 5/16" into the block.
There is a 5 bolt hole oil pump available which requires no extra holes being drilled as it is adaptable for 2, 3 & 4 bolt fixing but you will need to ask for it.
See http://www.somerfordmini.co.uk/eshop/in ... age&id=119
for details of the pumps available and details of interchangeability.