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Hi all,
I am having the 850 block and head dipped, mainly to get rid of the corrosion in the water jacket.
I have knocked the core plugs out. Do you think it is essential to take out the brass oil way plugs as we'll, or will the oil dissolve with the dipping any way.

Macker

Def take the plugs out I did mine and got a lot of muck out and used a shot gun cleaning
kit to scrub through too

+1 on taking the plugs out and using gun cleaning brushes to scrub out the oil ways.

Consider tapping the block and fitting pipe plugs instead of installing the same type of solid metal plugs that you will remove.

Yep your right, I will go for it. I need to make sure I drill the right ones now.

Thanks.

Good idea to replace them as the acid dip will eat away the brass plugs.

Don't ask me how I know ........

Macker2 wrote:Yep your right, I will go for it. I need to make sure I drill the right ones now.

Thanks.

Sounds like you are wanting to drill the plugs out in 'one go'? I'd suggest against this. I drill and tap the plug itself, then use a slide hammer to pull them, or you can wind them out on a bolt with a nut and a socket to draw them in to. It's all too easy to nick the block if you try drilling them all the way.

Unless you are looking to do an authentic resto, fit screwed plugs as dklawson suggests. I'm not sure that you can get the original style brass plugs in any event, but very easy to make what ever you need, just be sure if going for a brass plug again that it has a rounded lead in or it will likely shave when drifting in potentially leaving swarf in the oil way and a leaking plug later.

Thanks for all of the replies.
I am still trying to fathom which plugs come out. I have an 1/2" one at either end of the block but after that I am struggling. There doesn't seem to be as many pics about of the 850 plugs.
I plan to remove the plugs as Spider suggests and replace with BSP plugs.

Thanks
Macker

I'm not 100% sure just how many the 850 blocks have, but I do seem to think they'd be simiilar to all other small bore blocks. These are some photos I have on file (mostly 1275 stuff, but equally applicable);-















The plugs as shown 'Oil Pressure Relief Vent' you need to be VERY careful when re-fitting that you don't block off the vent pathway that relieves from the back side (spring side) of the Oil Pressure Relief valve. If these get blocked, it effectively stops the Relief Valve from being able to work and so causing the Oil Pressure to go sky high, high enough in fact to blow out the Oil Filter in fact (and that's usually the first sign).

It maybe frowned upon, but the advice I do like to give in regards to these particular plugs is to leave them. The Acid (or what ever else they use) won't affect them and they are on the non-filtered side of the oil flow path. These oilways can be cleaned and inspected fairly well in any event. If it were a Race Engine, then yeah, you'd pull them and fit plugs.

There's also 1 small plug in the head, which I'm sorry to say I don't appear to have a photo of on file.

<edit - Found one!



end edit>

In regard to plugs, for the Main Gallery, I fit M14 Cup Point Grub Screws and seal them with Loctite;-

Cheers Spider that's great. Thanks very much .
I am off into the shed to compare the pics. The wife is over the moon Haha.


Macker

I could only find these plugs 5 in total.

So I took these 3 out and left the 2 near the relief valve. Had a bit of an hairy moment when I lost the end of the pilot drill up the head. but it all turned out ok after a bit of upside down flushing with WD40

Yeap, sure does look like you've got them all, nice work.

When you come to fit this one in particular;-



fit this one first and check you haven't blocked of the port after fitting by looking up this hole (which has a slot head plug in it)



As I mentioned before, I use Grub Screws for the plugs. These small ones, I fit 5/16" UNF in to and for tapping the holes, I use a Taper Tap, then it works similar to a reverse taper threaded plug. So, when tapping this particular hole ^ just do a little at a time, then check with the grub screw and be sure you're not blocking off the vent as per the second photo here.

The bigger plugs, which are on the Main Oil Gallery, I fit M14 Cup Point Grub Screws in to. I would use 9/16" UNC, but very hard to find in these parts. Tap them nice and square and then follow up with a Plug Tap. Then when you screw these plugs in, they'll seat on the shoulder drilling in the block. Be very careful once again that these don't go in too deep or you'll be blocking off the gallery to the Main Bearings on 1 & 3!

Generally, you should only need about 4 - 5 threads on these plugs to achieve a seal and use some loctite for insurance.

Thanks Spider. Will finish off at the weekend.
The larger hole as you said seems the perfect size for M14.
Cheers

Macker

Removed these small plugs by tapping and pulling using an M4 bolt and nut. They are larger than the head plug and I will tap them same as Spider says above.
Block and head have gone to the dippers for cleaning now. Costs £45

Good stuff. Some people also pull the Oil Pressure relief valve seat too, but I'd suggest buying a new one before doing this as they can be hard to come by and half them time they get damaged in the removal process. Usually though, I leave them, it's un-filtered oil that goes through there anyway, it's only if the engine is particularly cruddy or a race engine that I pull them.

Any tips on refitting the core plugs (rather than the oil ones)?

Derek

NZmember wrote:Any tips on refitting the core plugs (rather than the oil ones)?

Derek

What type of block? There are different plugs between the blocks, ie, Small Bore & Cooper S has a Lens Type, the Big Bore had Cups.

I just push new core plugs back in using Araldite or JB weld as "lubricant". Never had any problems at all.

Thanks. It is Cooper S.
Derek

Ha, never tried Mark's Trick, but will keep it in mind.

I clean the block with a wire wheel in the drill, then clean the plugs and the block with multi-purpose thinners, then be careful not to touch them after cleaning. Then on the edge of the Lens Plugs, apply some loctite, I tend to use a medium strength one here, not so moch as an adhesive, but as a sealant.

Fit the plug in the block, they have a machined register, so all the way to that. Then working from the centre of the plug, tap them with a ball pein hammer, gradually working out until they are flat, don't be tenpted to hit them hard first up. This causes the plugs to expand and 'bite' in to the block as well as seal on the machined register.

I'll add I actually prefer steel plugs to brass ones. The are less likely to leak and paint up better!