24 replies to this topic

[Outofthegame]

You'll probably also need the smaller water pump pulley to clear the head. 

[Stiggytoo]

Apart from the pocketing and water ways, these are all very quick and easy mods to make. If you feel confident to do the pocketing yourself, there is a template somewhere online with dimensions you can work to. Prices must be around £60+ (That's just a guess, I can't remember how much mine cost) 

The waterways need to be 'moved' over rather than drilled out larger; as they won't align properly, possibly resulting in head gasket issues. Lots of people have done the 12G940 conversion without doing any of these mods to the block with no problems. The proper way to fix the water way issue is to insert a metal plug or grub screw into the offending waterway, then drill it further across to meet the waterway on the head and finally skim the block. Others block the waterway entirely. I opted to fettle away at a solid piece of plastic to make a kind of crescent shape which was knocked into the block and carefully trimmed away with a stanley blade. This has worked surprisingly well and I've had no issues with it. The only reason I did this was because I thought better of leaving it at the last minute, and this method left no swarf/debris.    

[olliewiltshire]

if you could post a picture  outofthegame, it would be a great help as you know what they say, pictures speaks a thousand words ahaha

 

i will prob get the pockets done by a pro then but will i have to remove my engine for this to get done?

[olliewiltshire]

Apart from the pocketing and water ways, these are all very quick and easy mods to make. If you feel confident to do the pocketing yourself, there is a template somewhere online with dimensions you can work to. Prices must be around £60+ (That's just a guess, I can't remember how much mine cost) 

The waterways need to be 'moved' over rather than drilled out larger; as they won't align properly, possibly resulting in head gasket issues. Lots of people have done the 12G940 conversion without doing any of these mods to the block with no problems. The proper way to fix the water way issue is to insert a metal plug or grub screw into the offending waterway, then drill it further across to meet the waterway on the head and finally skim the block. Others block the waterway entirely. I opted to fettle away at a solid piece of plastic to make a kind of crescent shape which was knocked into the block and carefully trimmed away with a stanley blade. This has worked surprisingly well and I've had no issues with it. The only reason I did this was because I thought better of leaving it at the last minute, and this method left no swarf/debris.    

so could you not move the waterways on the head instead of the block? im just thinking of the easiest way of doing this with out getting swarf everywhere! Your way does sound like a easier way, i dont suppose you have any pictures of your work just to help me visualize this? many thanks

[Stiggytoo]

No photos sorry, If you buy a 1275 head gasket, and lay it across the block, you will quickly be able to see which waterways are out. You probably could do the pocketing with the engine in the car, but you would have to be very careful not to get any swarf in the oil ways and bores. Depending on the condition of the engine, I would take it out and get it done properly as well as rebuilding the engine.    

You can't alter the waterways on the head as they need to line up with the 1275 gasket which you will need to use. If you arre't ginng to take the engine out, providing you have a safe area under the valve at something like 320thou valve lift you could just the head straight on. 

Edited by Stiggytoo, 15 May 2014 - 02:18 PM.

[Outofthegame]

Right so, 

 

The picture is a bit blurry, but you should be able to get the gist of what's going on. 

 

Between the head and the aluminium pumphead you can see where the metal has been ground down, in fact so far that the pinky/orange gasket behind it is showing. 

When you do I wouldn't grind as much as I have. 

 

To the right you can see a bolt head and a copper washer. I tapped that outlet in the pump, I then put a bolt in it using plumbers (PTFE) tape to keep it water tight, and of course the copper washer to be sure. 

 

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[Miniminx71]

Mike Vizard's "Tuning the A Series Engine" used to be my bible when I used to tinker. Worth getting hold of a copy if you haven't got one already.

[Outofthegame]

Do you mean David Vizard?

[Miniminx71]

Do you mean David Vizard?

I do! Jeez, never EVER thought I'd get that wrong! Ouch.

[Matt's Dad]

If you can get hold of a copy of Keith Calver's 'Mini Expert' guide series, "Tuning the 998 engine II" gives you chapter and verse on how to fit a large bore head on to a 998 block without having to pocket the block. It's well worth a read before you commit.