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MG Midget and Sprite Technical - cylinder head flatness
Its been a while since i was on here, but its time to get the midget back on the road.
I have a question aimed at anyone who has specific knowledge of the tolerances for cylinder head flatness.
I have just received a 1275 head bought on e-bay as a re-manufactured part. When I put a flat edge across the face on the bridge between cylinders, light is clearly visible, I can also pass a 0.3mm feeler guage between the edge and the face. I am guessing that this is a problem, but does anybody know what the acceptable tolerances would be?
The e-bay definition of re-manufactured is:
Remanufactured: A properly rebuilt automotive part. The item has been completely disassembled, cleaned and examined for wear and breakage. Worn out, missing or non-functioning components have been replaced with new or rebuilt components. It is the functional equivalent of a new part and is virtually indistinguishable from a new part. See the seller
|just because your right didn't mean you get to have your own way|
I think your looking at a fight.... how much time are you willing to invest before you realize no one is going to play ball with you
Check with your credit card company ... they might be able to claw the money back .. but it depends on there policy ... and you will have a short window
|In the bad old days the legal definition of "reconditioned" meant not much more than being given a coat of paint.
Ebay+Paypal usually side with the buyer, so if you're not happy with it ask for a return. Do it via their messaging system and be polite but specific about why, and attach photos. You'll probably end up paying for return postage (do this as tracked and insured, to prevent seller claiming it was lost or damaged in transit) but otherwise should be possible to get money back.
In UK distance selling regulations also apply, don't know about the theory or practice in Italy.
|Do you know that your straight edge is indeed straight as from the photo it looks like an ordinary piece of bar which may not be straight.|
|engineers blue and a flat surface I used an old mirror it gives you a good idea of whats flat mine didn't look good so checked it on a level surface table we had at work,|
|Could you get it checked professionally and skimmed if necessary. If you return it you still need to buy another - if you can rectify it at least you know for certain what you have, even if it may have cost a bit more.|
Alternatively use it and see how it goes - I take it you just want to get your car back on the road and are not building some sort of race car etc
|S G Macfarlane|
|33mm is right for a standard 1275; 35.6mm for a Metro.|
Those of us with a 948cc engine can only aspire to 30mm (27.8 standard).
|Nick and Cherry Scoop|
If you have no luck with an ebay or card provider refund, then you might want to spend the 'return' postage cost to UK instead on sending it to someone like Peter Burgess for a proper rebuild.
See: http://www.peter-burgess.com/page12.html (or outright purchase ones: http://www.peterburgessshop.co.uk/CylinderHeads.html)
Alternatively, are there Mini and Midget racers/specialists who could do a 1275 cylinder head rebuild for you in Italy (or Germany if not too far from you)? Any suitable standard Metro heads out there for you? (the experts on here will be along to say any issues with fitting a Metro head to a Midget block).
That head has been resurfaced by a dodgey machinist and will need remachining
What has happened is--the surface grinder has been set up with too much back clearance on the wheel causing it to machine a concave trench through the centre of the head surface
It will probably be quite straight length wise but scooped out along it's length
A resurface will fix that
As far as the valves go, they are possibly just saying it's a big valve head compared to early heads
Zero is the best tolerance for head flatness
0.3mm equals .012" --way too much
0.1mm--.003" would be absolute max.
Can you explain what you mean by that and back clearance. I have a surface grinder am am not aware of that problem with them. The main problem I have seen in the past on some surface ground products is wheel bounce.
When I've surfaced heads in the past I have used a shaper and when I have had it done by a commercial shop they have always fly cut it with a fine cut which has been suggested helps hold the gasket. I would fly cut them myself by don't consider my aged BP accurate enough for a head.
It just occurred to me that you're likely referring to a vertical shaft grinder with the cylinder head face horizontal so in that case I know what the back clearance is. I normally think of a surface grinder such as the one I have which is a horizontal shaft and you typically make multiple passes across the horizontal surface.
|Hi everybody, all comments are much appreciated, particularly the technical ones, very helpful.
A couple of things I have looked into which I will pass on.
Regarding the distance selling regulations in the UK, it appears that if the item is faulty or not as described then you are entitled to the cost of the return postage to be met by the seller. If you just change your mind about the item or have made some mistake in the order, then it is the buyers cost. You basically have 14 days from delivery to reject it and another 14 days to return it to the seller.
William R, yes it seems to be out by a factor of 3 on the tolerance, I'm guessing this would lead to gasket failure, compression problems or fluid leakage, so it isnt going on the car as is.
I have contacted the seller regarding the issues I mentioned (there was also some minor damage- broken and bent studs caused by poor packaging). His initial reaction was not so bad, asking me to send it back for inspection.I am approaching this offer cautiously for now, as soon as it leaves me he could just dispute the points. I have asked him about the return costs and am awaiting a reply, so we will see how willing he is on that one. Plan B will to be get it re-skimmed locally and leave some appropriate feedback.
I have asked him about his tolerances, he is a seller that seems to deal in Reconditioned A-series heads,so he should be able to answer that point if he is serious
Getting parts in Italy would be very difficult if it wasnt for the internet and apart from this one I have had nothing but good experiences from e-bay and the likes of Moss, so far.
Thanks again for all comments I will update this thread as it progresses, it will be interesting to see how much weight these consumer rights carry with sellers.
This thread was discussed between 04/01/2018 and 06/01/2018
This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.