Morris Minor Owners Club

Given that my alledged 948 head is incredibly dirty, do I spend time cleaning, replacing valve seats,guides, valves, or general de-coke and re-grind, or leave well alone as the engine was working until car laid up for other reasons (problem with the heater tap fiting and studs therefrom not fitting/breaking is the main reason for removal of head. ) , mostly on grounds of lead memory in existing valve seats.

Second issue is my 1098 spare head, I was going to fit new seals etc, and removed the valves (all placed in plastic pot randomly), now as there may be some lead memory is it going to be a significant power loss if i randomly refit valves to any location? (reminder to self new spring required). I don't need a replacement head other than the one I had re-built i dont think were lapped in as I seem to have a bit of a lack of power (struggle to 50 and v unhappy beyond that)

ian

You seem to be getting into a spot of bother with all these issues, If I were you I'd decide which head I wanted to use on the car, then clean it up, (to make working on it nicer), strip it all out' inspect, replace things you're not happy with and then rebuild it. If you do this you will know that side of things are done and out of the way. Then you can move on. Don't get tied up with spare heads etc, all you want is a decent one on your car.

Whatever head you decide to use - it MUST be thoroughly cleaned and checked for flatness - and for cracks - almost certainly needs new guides and every chance it will need new exhaust valves - although inlets tend to last longer and could well do another turn. The valves WILL need grinding in, possibly seat cutting, although determined grinding should be enough. Don't get so caught up in 'lead memory' - it's the very least of your worries..... The 1098 head (marked 12G 202 ??) is a much better head - but will need all the above attention AND will need skimming by 60 thou before use on a 948 engine. Your engine struggling to exceed 50 mph is desperate - can't see it just being down to 'valves not ground in'.... A compression test would be a GOOD IDEA...

I am thinking that the lack of power is dirty fuel and a carb overhaul, and also going to re-check the dizzies.

Meanwhile this is the re-con (1098) head, I think it has had oil down the 'valve guides' (its been bubbling around 2/3 cyl spark plugs externally) (I hope not past the rings). Been on for about 1000 miles. Are the valve springs going to make much difference- one broke first time of fitting them, so got a new set of medium AP springs and fitted them. As stated the valves came with the re-con but were not fitted, the collets were different profile to what I had in the old head , as it was I had a bucket of collets in the garage that did fit, but (mentioned elsewhere), the oil seals appear to be awol or unfittable (I'll attempt to check the profiles as per other thread comment), more pixs at the weekend when the bench strip down ( and replacement cereal box to hold the valves in order ) comes into play- I'll check the valves for leakage first with parafin into the chambers over a box- presumably with springs still in situ.

We also ended up with appearing black smoke at the exhaust - I think thats been a mis-fit of the choke settings - with too rich mixture, will strip out and lub the cable its a bit tight on its routing past the heater valve.

(The saloon at present has an old head off the traveller- straight swop done in 4 hours ( the bungy cord trick holding up the carb and manifolds to the bonnet is a time saver ). ( Would have been 3 hours had I remembered to drain head through the bypass hose first ). We will also at leisure strip the block of the traveller engine to check for bearing wear , attempt to fit new oil seals etc as we go as well and check on the oil pump / camshaft - I'd like a little extra power so maybe there is a better camshaft to fit- theres a mini specialists 300yds away from me I will probably source from them.[frame][/frame]

I don't like the look of the No. 2 exhaust valve, it seems to be about to disappear into the exhaust port in the very new future?

Did you do a compression test before removing the head? Do you have pictures of the pistons/bores?

As earlier in the replies, one good head is the priority.

I've never seen such a poor exhaust valve ! And the others don't look too clever either... I suggest the head is basically 'scrap' now - although it may be possible to save it by fitting new 'unleaded' seats (and new valves of course)... although whether the cost is justified is doubtful.. The head surface also looks poor - has the gasket been blowing across the face ? What does the block surface look like ? The only 'better' camshaft worth fitting to a 1098 is the 'MG Metro' cam (or perhaps the similar 256 from some 'tuners' ) - since the engine can't take more than 6000 rpm - stronger valve springs are not wise either... If you really want to improve a 1098 you can't beat fitting a 940 head from a 1275 engine - which works very well with the standard camshaft. Read up on what's involved - it's not a straight swap - but not difficult either. Of course the engine needs to be in very good condition, or it's all a pointless exercise....

bmcecosse wrote: If you really want to improve a 1098 you can't beat fitting a 940 head from a 1275 engine - which works very well with the standard camshaft. Read up on what's involved - it's not a straight swap - but not difficult either. Of course the engine needs to be in very good condition, or it's all a pointless exercise....

any recomendation for suppliers and link to any decent threads?

bmcecosse wrote:I've never seen such a poor exhaust valve ! And the others don't look too clever either... I suggest the head is basically 'scrap' now - although it may be possible to save it by fitting new 'unleaded' seats (and new valves of course)... although whether the cost is justified is doubtful.. The head surface also looks poor - has the gasket been blowing across the face ? What does the block surface look like ?

Think the photo makes if look worse than what it is but still not great I think this was a recon unleaded head. as write though have a feeling we may have end up with old valves in a new head as I dont rember seeing the old valves in the old head.
- Leason learn't 1) when a 12 year old (me as i was that the time) is bored and wants to start playing with cars don't start trying head swaps & 2) swapping to an unleaded head when the previous is ok propably not worth it.

main concentration now is to build a good engine based around the 1098 block using standard parts with appropriate modifications for the traveller. and sort out carb on the curent slightly bodged to together to keep running engine. cuts out when on throttle randomly. whyperion to clraify

I doubt these are 'unleaded' seats.... Find another head for your engine.

Think we still have the head that was on it before all be it leaded don't think was a lot wrong maybe worth build up again depending on cost for any other 1275 head etc.

Think we need to clarify what we have where;

948 engine, head, starts requires improved carb and timing - in 4 door saloon. ( 947)
1098 Engine currently without head now gearbox else where - for traveller (P)
1098 Engine now with head from traveller, starts requires improved carb and timming - 2 door saloon (F)
1098 Unleaded head supposedly - now questioned (pictured) - just removed (due to leaking oil through 1 & 2 spark plugs on 2 door saloon (F)
1098 Leaded head with valves & spring removed ( think ) - originally on engine from 2 door saloon (F)

Aim working 948 in 947 as standard, working 1098 engine good performance with abillity to easily run unleaded as an daily driver for traveller (not spending money for spending money sake however) , possibly another 1098 engine made up how ever with focus on spending little money (repair only) i.e. using what we have availble and not modifying.

Is the exhaust valve on #2 smaller diameter than the others or just an optical illusion...? Doesn't look ideal. If it is smaller then the head itself might not be too bad

For an idea of costs involved in putting a 1098 head on a 948 engine (60 thou skim as mentioned above) I've just finished a 12G295 head for my 1098, so an 80 thou skim. Work included 8 x new guides, 8 x new valves, skim, seats recut. I fitted and reamed the guides myself. While I was on, I went with a new rocker shaft and fitted new rocker bushes and reamed to suit. The total has come to just over £200. £75 on parts and the rest on machining. Having a machine shop fit the guides would probably add another £80 to the bill. I didn't ask about hardened valve seats but then thats low on my list of priorities.

Indeed - no need to worry about 'unleaded'. That's a LOT to spend on a 295 head though.....when a 940 can be picked up for maybe £40 or so... Guides are about £16 - rocker shaft as required of course, and every chance the valves will be good (much better quality in the 940 heads) - and just need to sink the exhausts by up to 40 thou - and it's a much better head - terrific on a 1098.

Lucky I picked the 295 up for £30 then at Beauleau from someone who didn't know what it was Given it is a more desireable head there'll always be more value in it than a 940.

bmcecosse wrote:Indeed - no need to worry about 'unleaded'. That's a LOT to spend on a 295 head though.....when a 940 can be picked up for maybe £40 or so... Guides are about £16 - rocker shaft as required of course, and every chance the valves will be good (much better quality in the 940 heads) - and just need to sink the exhausts by up to 40 thou - and it's a much better head - terrific on a 1098.

any recommendations of where to look for such items?

Ebay, Mini Spares (minispares.com)

To make it worth while conversion what else should be changed/improved? thinking of carb and manifold etc.
and how realistically do get over a good running standard 1098 with everything in good order?

A 295 is not 'more desirable' than a 940 - unless someone wants it for originality on a 998 Cooper or an MG1100. The 940 gives way more power.
'tim' asks how much - - but we have no idea how good your base unit is ! There's no point trying to get extra power from a less than perfect engine - so do you have a 1098 with GOOD bores and excellent crankshaft bearings? If so - strap on a 940 head with the exhaust valves checked to have 320 thou clearance - add a 1.5" carb on a good alloy inlet and you will have a reliable ~60 bhp without revving the nuts off it. Should be do-able for £50/£100 - much less if you make some good deals !

Obviously a 940 gives more power(flow). I made the example of a 295 as I've just done one. Rarity does tend to lead to desirability with most things.

You could cobble something together for £50-100 but I've seen plenty of engines done on too small a budget that need other work doing to them a year later. If a bodge is nice, a bodge will suffice as they say

It's not a bodge, it's very necessary if you want BIG valves - and I do like the 295 heads - I have two 'in stock' . Probably the best upgrade for a road going 948, but the 1098 definitely goes much better on a 940. Sadly realisation of the easy power from a 940 has dropped the value of 295 heads quite considerably .. although your purchase was definitely a bargain!

bmcecosse wrote:but we have no idea how good your base unit is ! There's no point trying to get extra power from a less than perfect engine - so do you have a 1098 with GOOD bores and excellent crankshaft bearings?

we have the engine from the traveller half stripped down now - (head robed) going to start having a look at bottom end and block at the weekend so going to want to get it GOOD anyway. so if there is a significant benefit then will look to sourcing parts for head conversation.

Is there anything in particular we should look for, and any tips or advise on how to go about stripping it down?
will report back on this and ask for advise as to how to proceed.

Just follow the Workshop Manual procedures. Note which way round the mains caps fit -mark them if possible. Note which con rod+piston comes out of each bore, and keep the big-end caps with the rod they came off ! And use the correct well fitting sockets on the bolt heads......