crack in cylinder head

Post by **Dru** » Sat Sep 27, 2008 5:53 pm

Well, the Trav's been running unevenly lately and the coolant has been disappearing and it's been getting hot, so I thought I'd see what was going on in the cylinder head.

The head gasket is blackened between each bore, and there's a worrying little crack that looks like this

<a href="http://www.flickr.com/photos/belvedere/2891960585/" title="moggy head by Dru Marland, on Flickr"><img src="http://farm4.static.flickr.com/3044/289 ... 631b3d.jpg" width="500" height="493" alt="moggy head" /></a>

...do you think this is something to worry about?

Post by **bmcecosse** » Sat Sep 27, 2008 5:55 pm

Scrap head I'm afraid. Keep the valves etc as spares - but that head casting is now door-stop material. You need another 12G202 head to replace it.

Post by **Dru** » Sat Sep 27, 2008 5:59 pm

O lor'....

Well, thanks for the forthright advice. I can at least stop faffing with it. Is it worth transferring valves and rockers over to a new head, or is this a false economy?

Post by **bmcecosse** » Sat Sep 27, 2008 6:13 pm

Well - you won't get a 'new' head these days - just 'another' head - so certainly keep the valves/springs/cotters etc as spares. If you are not too bothered about performance - you could fit an 'unleaded' head from a 998 Mini - they are very very cheap and usually plentiful! The inlet valves are slightly smaller, hence slight loss of top-end performance - but in daily use the car will run fine. And they are 'unleaded' if that bothers you!
Here's one - http://cgi.ebay.co.uk/mini-998-head-998 ... 286.c0.m14
And another http://cgi.ebay.co.uk/Mini-998cc-recond ... 286.c0.m14

Post by **Dru** » Sat Sep 27, 2008 6:17 pm

I'm one of nature's worriers, everything bothers me! ...I do quite a lot of miles, so I guess I'd better go for the 1098. Unleaded.

Post by **bmcecosse** » Sat Sep 27, 2008 6:22 pm

There are many more of the 12G940 heads (from 1275 engines) - which can be fitted to your 1098 and will give you considearbly better performance! Only snag is - you need to have the exhaust valves in that head re-set into the head by 40 thou - but it's a simple job for any machine shop (or competent garage) to do.
An 'unleaded' 12G202 head for your 1098 engine will be v expensive - especially as you now have no trade in. Fit a 998 Mini head for now - I doubt you will notice any serious drop in performance.

Post by **bmcecosse** » Sat Sep 27, 2008 6:43 pm

Here's an engine not TOO far from you ! Grab the head off it and keep the engine for spare. http://cgi.ebay.co.uk/Morris-minor-1098 ... 286.c0.m14

And - advertise in the Forum for a spare head - there's bound to be one floating around near you.

linearaudio · Post by **linearaudio** » Sat Sep 27, 2008 8:11 pm

[quote="bmcecosse"]There are many more of the 12G940 heads (from 1275 engines) - which can be fitted to your 1098 and will give you considearbly better performance! quote]
I was just waiting for that one, Roy!! But shouldn't he upgrade to-.... pause for fanfare-... WOLSELEY brakes first?!!

PS do you need to recess the valve seats? According to calculations I've seen (Des Hammill) it should all clear, just, with standard lift.

Post by **wanderinstar** » Sat Sep 27, 2008 8:30 pm

Noooo.... Riley brakes. Much better.

Post by **bmcecosse** » Sat Sep 27, 2008 8:36 pm

Well - you can chance it if you like - but I have made the measurements and I KNOW it has to be done ! You 'may' just get away with it on a 948 engine - with it's ghastly standard camshaft - because it has very low lift on the exhaust cams - but the AEA 630 cam in the 1098 engine has rather better timing - and half-decent lift on both inlets and exhausts - it will clash! "Des Hammill" - you must be joking, surely!! But the exhaust valve sinking is easy to do - it took the lad at my work all of 5 minutes to do all 4 seats! In fact - buy a 940 head where the valves have self-recessed due to unleaded fuel - and good chance you won't need to do anything!
Of course W brakes should be the first item on the agenda - but they are not common these days i'm afraid!

linearaudio · Post by **linearaudio** » Sat Sep 27, 2008 9:32 pm

Sorry, I wasn't really doubting you, just wanted to confirm. Not sure that I like the style of Mr Hammills writings- seems a bit brash/go for it to me. I'll stick with you as the fount of all A series knowledge!!

If Wolseley brakes are difficult to source, what about your Riley brakes, then! Cue comment from "disc brigade"!

Post by **bmcecosse** » Sat Sep 27, 2008 9:35 pm

Riley brakes also hard to find, and cylinders/shoes more expensive. They are quite a bit wider than the W brakes. Ian seems to like his - although I remember him saying they were 'heavy' when he fitted them.

Post by **Dru** » Sun Sep 28, 2008 8:09 am

Those are very good links and suggestions, bmcecosse; the engine is tempting, but I'm short of storage space and live on the third floor, and my workshop is also the kitchen table.

I'll put up a wanted notice, and ask around in Bristol too.

By the way, there's almost certainly a very good reason why cracks like this aren't repaired by welding. What is it?

...the brakes I've got seem adequate, with the servo addition; I've managed a few emergency stops whose suddenness kind of took me by surprise. Not to mention my small passenger...

Post by **wanderinstar** » Sun Sep 28, 2008 8:54 am

They seemed to be when I got them, but I'm used to them now and don't notice it.

EDIT. Ahh now I know how double posts happen. There was an error message saying "Unable to display this page" so I clicked Submit again.

To save your embarassment Ian I have removed the other posting

Kevin.

Post by **bmcecosse** » Sun Sep 28, 2008 10:58 am

Maybe someone would store the engine for you - after you decapitate it! Welding/brazing these heads - it can be done - but really not a great long term success rate and not usually worthwhile. You should get a Mini head for ~ £10, I have given away complete 998 Mini engines in the past, and they are often offered free on the Mini forums.

Post by **rayofleamington** » Sun Sep 28, 2008 5:28 pm

I was just waiting for that one, Roy!! But shouldn't he upgrade to-.... pause for fanfare-... WOLSELEY brakes first?!! PS do you need to recess the valve seats? According to calculations I've seen (Des Hammill) it should all clear, just, with standard lift.

If the 12G940 is well used then it may be fine on its own - Production tolerances vary and so does the VSR. I've run 2 of these without needing any mods, but you need to check distance between valve and gasket face to be sure.
I picked up an unleaded 12G940 and it was nearly new condition, but valves sat much closer to the gasket face, so that one needed modification.

I'll stick with you as the fount of all A series knowledge!!

yes - he has managed to aquire a few tricks from us on here. Before I told him the valve sinking method, he was cutting bits out of the block with hand held tools ;-)

Post by **bmcecosse** » Sun Sep 28, 2008 6:37 pm

Err -not me Ray - I had been sinking the valves in 1275 heads a long time ago - long before I even joined this forum ! But many (including lots on here) don't agree with it and insist on pocketing the block.
I have of course pocketed a block too - some 40 years ago now when I ran a full race Cooper S head on my 998 Mini race engine !

Post by **rayofleamington** » Sun Sep 28, 2008 7:32 pm

Err -not me Ray

funny - IIRC you were recommending pocketing the block as the only solution, and explaining how you'd been doing it using a grinding stone in a hand drill. ;-)

Post by **bmcecosse** » Sun Sep 28, 2008 8:58 pm

Oh yes - that's how I did it - but also using 'sunken' exhaust valves, although I may not have promoted it on here - having had a hard time when pushing that method on the Mini Forum !

Post by **les** » Sun Sep 28, 2008 10:48 pm

I expect the gas flow would suffer if the car was tuned to any extent, usually it's a sign to reseat when the valves are sunk.