My Engine Rebuild

[James k]

How could I shorten them myself? I'd like to keep the cost down as much as possible.

[bmcecosse]

Just cut them with a hacksaw - then tidy with a file ! I ground mine off in the valve throat as part of the 'gas flowing' going on there. Since you only want the seals for the inlets - just get 4 of the grooved guides...and 4 standard guides without grooves for the exhausts.

[James k]

Okay, that's a good idea. What's the disadvantage of using the longer ones? More obstruction to air flow and less power?

[philthehill]

The longer valve guides to some degree obstruct the inlet and exhaust tract when fitted at a height of 19/32" above the valve spring seat. How much power is lost by the obstructions is any ones guess - but it is better to have as much air flow into and out of the engine.

[bmcecosse]

They are also designed to be used with the longer valves used in the 940 head. Shortening the guides (some folks 'bullet nose' them) and removing the 'bump' in the inlet throats is a major part of gas-flowing a cylinder head.

[James k]

Do I need to file in the ridge on the guide when I cut them down?

I've just spent a couple of hours cleaning the block. After about an hour of wiping the oil off with kitchen towel I used a toothbrush and white spirit to clean it up fairly well. It will still need a couple more hours probably but it's getting there. How do I clean out the oil galleries?

[philthehill]

You cut the longer valve guide at the valve head end not the end with the seal groove if that is what you mean by the ridge.
If you want to do the gallery cleaning job properly you will need to drill out the blanking plugs and run brushes through the galleries and then when all cleaned fit new blanking plugs or as I do fit screwed plugs instead of knocked in plugs.

[bmcecosse]

Some take out the plugs - I don't suggest you do that.. Just squirt some white spirit down - and up! Probe with a bit of stiff wire if you like - but make sure you don't use eg pipe cleaner and risk leaving some of it in the gallery!

[philthehill]

If you remove the plugs to clean the galleries you can use these brushes:-

http://www.frost.co.uk/engine-brush-cle ... s-set.html

Even if you do not clean the galleries they are a useful addition to the tool box.

I personally would not start a rebuild without having cleaned all oil ways and oil galleries.

If you have had any machining work done on the engine block or head etc. you must clean all respective oil ways and oil galleries. Additionally those oil ways running through the crankshaft should be cleaned before starting assembly even if the crank has not been re-ground.

There is no such thing as a too clean an engine - especially internally. It only takes one little bit of crud, swarfe or milling dust to ruin an engine.

[les]

The plugs conceal a lot of crud as basically it collects down a blind hole, there are threaded plugs available if you do remove the original ones, unfortunately you have to tap the ends of the galleries to accept them. I personally think the extra work is worth it if you go as far as a complete rebuild and as Phil says you can't go overboard when cleaning an engine!

[bmcecosse]

The problem lies in securely fitting new plugs - which without being over critical, I wonder about if you can fit a thermostat upside down! I suggest you stick to probing and squirting... Back to the guides - you 'obviously' don't cut off the end with the oil seal groove !!

[les]

They are put in with an Allen key and a smear of sealant, quite secure! However James has a few options to choose from now!

[James k]

Okay Roy, I'll fit new plugs, and they'll be secure. You'll see!

Phil, yes, I was referring to the valve head end. By 'ridge' I meant the bevelled edge at the bottom. I wondered if it needed to be there so that the guide could be knocked in easily. Or indeed if it served another important purpose.

Those brushes look like a good idea, I think I'll get them.

[bmcecosse]

First you need to tap the holes correctly... Just chamfer the cut end of the guide with a file - or roll it against a rotating grinding stone (eye protection). I'm concerned you are encouraged to get out of your depth with this engine build... Since the engine has not seemingly 'seized' or 'blown up' in any way and the crankshaft looks to be fine - there is unlikely to be any shrapnel/swarf to worry about. Squirts and probes is all I would be doing!

[les]

I will agree it is quite an involved process.

[James k]

I just want to avoid cutting any corners. I want this engine to be as good as it can be and last as long as it can. If it's really worth doing something, I'll do it.

[philthehill]

If you fit the original type oil gallery plugs which are just a knocked in - the process is quite simple.
Just drill out old plugs - clean galleries and knock in new plugs.

This is the link to the parts required.

http://www.somerfordmini.co.uk/eshop/in ... age&id=108

Items Nos: 3, 4 & 5 required.

For the main galleries you can choose either solid or cupped plugs. The choice is yours.

For those who have David Vizard's book on Tuning The 'A' Series there is a very good description relating to cleaning the oil ways/galleries titled Block Preparation in the section 'Blocks, Cranks, Rods & Pistons. It also describes fitting either tapped plugs or original type.
Phil

[bmcecosse]

Worries me that 'knock in' plugs could 'knock out' on a dark and rainy night - with instant wrecked engine.... Wouldn't be me !

[James k]

I've now removed both the oil gallery plugs, given the block another good clean and wire brushed the paintwork. I'm not going to do a proper thorough clean of the oil galleries etc. until any machining work has been done. I'm not sure whether to paint it before or after machining.

Is there a good way of cleaning out the waterways?

[philthehill]

As regards the knock in oil gallery plug blowing out.
They were knocked in when the engine was originally assembled by BMC/BL and I have never come across or heard of a plug having blown out.
The reality is that the main gallery plugs are of quite a small diameter (12mm) and so even at 75 lb/in sq oil pressure the pressure on the inner end of the plug is quite low. The rest of the oil way/oil gallery plugs are even smaller so even less pressure on the plug.
The only reason that threaded plugs are fitted is so that the oil galleries can be easily cleaned as required.
As regards my engines - on the initial build all of the oil gallery and oil way blanking plugs were/are removed and threaded plugs inserted for ease of oil gallery and oil way cleaning.
Phil