Sleipnir's in for surgery...

Post by **wiglaf** » Sat Sep 19, 2009 10:47 pm

Not the most major operation, but Sleipnir's spending this week at the garage. When I get her back, she will have a new, unleaded, head, and four new tyres.

Here's looking forwards to having a top speed over 55 again, and grip on the road!

Post by **bmcecosse** » Sun Sep 20, 2009 10:16 am

Good luck with the 'unleaded' head!

Post by **wiglaf** » Mon Sep 21, 2009 6:24 pm

Cheers - one two many miles with my foot to the floor, and it had to happen... only after arranging everything did I see your posts about using mini/metro head, and the possible benefits. Still, I'll be "maintaining the character of the car"

Post by **bmcecosse** » Mon Sep 21, 2009 8:27 pm

Depends how they do the 'unleaded' head! Are you inspecting the work as it goes along - could use the excuse you want to post the details on this forum! Interesting to see if they actually machine out the old valve seats - and press in new hard ones, and do they fit new guides and new valves ?? And possibly new valve springs too ?

Post by **webbnuts** » Mon Sep 21, 2009 10:47 pm

Sorry to hijack this thread, but am I right in thinking a 12g940 1275 head will bolt on my 1098cc block to get bigger valves? I'm rebuilding a 1098 to go in Blackie, and wan't to get a little extra out of it.

Post by **bmcecosse** » Mon Sep 21, 2009 11:08 pm

Yes it will - and gives excellent results. But you MUST check if the exhaust valves will touch the block - some heads will 'get away with it' - others you need to sink the exhaust valves into the head by 40 thou. Use a 1275 head gasket - and check there is clearance above the water pump which may need a bit of hand filing - nothing serious. Then - you must either use 1275 rocker assembly - or carefully re-align your own rockers so they operate directly over the tips of the exhaust valves.

Post by **wiglaf** » Tue Sep 22, 2009 4:53 pm

Ian's not doing up the old head - he's swapping it for one that's already been reconditioned, supplied by ESM. Is this by any chance the moment when everyone turns around and asks if I don't have a set of spanners to perform such a simple job myself?

I was more referring to possible difference in performance with a different head - though I suspect that peripheral costs of putting it in might have been higher due to the need to change the rocker assembly etc?

Post by **bmcecosse** » Tue Sep 22, 2009 10:54 pm

ESM head - hmmm. Good luck! Head change is about an hour's work - less if you know what you are doing! The 940 head can be used with the 1275 rocker gear without any changes - however - it's the horrible sintered rockers, and the nice pressed steel rockers that come with most Minors are much better - but would need re-aligning on the shaft - which does take an hour or so, but is quite satisfying to do well!

Post by **webbnuts** » Tue Sep 22, 2009 10:58 pm

Thanks bmcecosse. If I use a mild road cam, will I definately need to sink the exhaust valves in, or does it just hold the valves open for longer rather than open them further?

Post by **bmcecosse** » Tue Sep 22, 2009 11:08 pm

Standard BMC cams up to MG Metro (and the useless 731) have the same lift. Only when you go to the 544 and the 649 does the lift increase. If you use a 'reground' cam then it 'may' have increased lift - in fact - that may be all it has! No extra timing - just a bit more lift!! Best to avoid - these cams cause wear and tear on valve gear, and will indeed make the valve-hits-block problem much more likely. have to advise anyone doing this conversion to make your own measurements - and then decide what to do. But 40 thou sinking with the AEA 630 (standard 1098 cam) and the slightly better 2A948 cam (997 Cooper cam) is perfectly safe assuming the head has not been skimmed of course - and the excellent MG Metro cam has the same lift, and so also will be safe.

Post by **wiglaf** » Sat Sep 26, 2009 8:10 am

ESM head - hmmm. Good luck! Head change is about an hour's work - less if you know what you are doing!

Well, I've had all sorts of other parts from ESM and never had a problem, plus it does come with a guarantee... and I don't think I do know what I'm doing where this is concerned!

Tell you what, I'll let you know if it goes horribly wrong - and if it does so, I'll fit the next one myself - and tell again you when the engine subsequently explodes

I'm off to pick her up in an hour, and admittedly it is a bit more of a pain in the wallet than I'd like