Liners seats prep - how far to go?

[Geko]

Gents, this is as far as i can get with the wire brush, yet the seats are pitted quite a bit. Shall I attempt something more drastic i.e. with Dremel grinder ?

 

As always

Edited August 30, 2017 by Geko

[RogerH]

Hi Stef,

the people I use here can pickle the block completely clean of any rust etc.

The rust pits then show up a treat.

 

What to do with them !!!

The perfect answer is to get the seal face machined square with the top of the block.

You could fill the pits with something like JB Weld.

Or simply leave them alone.

 

If you look closely nearly all the seal face is clean - just the odd spot. Have you had a water leak in this area to your knowledge.

 

Roger

 

PS - do not use your Dremmel. It could cause more problems.

Edited August 30, 2017 by RogerH

[Geko]

Hi Roger, apart from having water evaporating in the ether at a rate of 1 liter a week, no know leak in this area... But the Fo8 on 3 and 4 were seriously corroded and black in color, so yes most likely they were leaking. I think i'll give it a final pass with the wire brush and then seal the Fo8s with whatever silicone sealant I have in store.

[Motorsport Mickey]

If the engine blocks out of the car you could drop it into the local machine shop and get the liner seats recut and equalised for height (bear in mind what liner Figure of 8 gaskets you have to bring the liner height back up to + 5 thou over the block deck) which is what I've done for particularly bad blocks (2). But honestly that block isn't that bad.

 

If you look around the inner "edge" dia of the liners that is the important seal edge, preventing any escape of coolant into to sump, any corrosion on the further outer dia closest to the block walls is incidental. From my Mk 1 eyball of the photo only 1 liner (number 3) has a problematical area where corrosion has crept under and there are some "dints" in the liner shoulder surface as it "siameses" onto number 4 liner shoulder. As Roger has said previously clean the liner surface with fine sandpaper, any scratches will be covered with Wellseal or your choice of sealer anyway, and then level any corrosion depressions in the liner shoulder surface with J B Weld which has good heat resistance (the liners heats are controlled by the water surrounding it and unlikely much more than maybe 150 deg). I would only do that on liner shoulders with those depressions in them that get to the inner edge, smooth the J B off before it sets and then again smooth down so there isn't any over the rest of the liner heights. Coat with Wellseal and then coat the copper FO8 gaskets both sides with Wellseal and place into position on the liner shoulders (after all liner heights have been measured and equalised dry first) and you're away.

The liners when clamped will do a champion job of "squidging " the Wellseal and preventing water penetrating the liner seals.

 

Mick Richards

 

PS: Stay away from it with a Dremmel.

Edited August 30, 2017 by Motorsport Mickey

[Geko]

Thanks Mick, I have gently sanded the liners seats with a 120 sanding disc on the drill and it's all clear now, well to my standard...Now my question is how do I compress the sealant until it dries? Shall I just put the head back on without gasket and torque it loosely? Also, what the best liquid to use to assess potential leakage?

 

Cheers

Edited August 30, 2017 by Geko

[Motorsport Mickey]

Thanks Mick, I have gently sanded the liners seats with a 120 sanding disc on the drill and it's all clear now, well to my standard...Now my question is how do I compress the sealant until it dries? Shall I just put the head back on without gasket and torque it loosely? Also, what the best liquid to use to assess potential leakage?

 

Cheers

 

Only use sealant after you've checked all liner heights and you're happy there is no difference in liner height around the liners down to the block surface, should be between 3 and 5 thou but do try and get the liner heights all the same ie 5555 or 3333 rather than a mix of 5535 which gives a reduced clamp in the centre and a possible gasket blow in the future.

You can torque the liners down to 105 lb ft using an old gasket when you're assembling dry and retain with large washers to do your measuring, nip it down to about 40 lbs it's not critical. Then when all heights are good remove the liners and FO8 gaskets and cover the liner seats with your sealant and both sides of the FO8 gaskets (messy) then gaskets in followed by liners, me ? I pull it down again to 105 with the old gasket and recheck the liner heights, I've found bits of grit (no I don't know where from) like to throw themselves onto the liner seats and bingo you've a liner tilted seating maybe a couple of thou up and a possible water leak on the FO8. You're grateful when you find it even if you have to pull 2 liners and do it all again.

Then refit with new gasket and pull the head down to 105.

 

Mick Richards

[BrianC]

Really interesting stuff but it makes me so glad I had my engine professionally rebuilt (and can now understand why it wasn't cheap!).