Jump to content
Gazzar

V8 pinning liners

Recommended Posts

I've almost bought a 4.6 V8, for another project.

And I've been looking into the mobile liner issue.

On an MG forum, I came across an article that suggested pinning the liner to the block.

Drilling a hole through the block and liner, below the water jacket,  and tapping it, then screwing a screw into the hole to pin the liner in place.

Has anyone actually done this?

Why wouldn't it work?

 

Share this post


Link to post
Share on other sites

On the V8's that do suffer with liner slip, it's usually a consequence of deeper issues than just movement of the liners itself. Porosity, super thin bore casting due to core movement during casting or corrosion of the bores behind the liners let's coolant in behind them. Couple that with the seam line between liner and block being directly under the sealing ring in the gasket (that top hat liners neatly fix) and it can all add up to a bad combo if you're unlucky and have a duff one. A well executed top hat conversion will have had the bores thickness tested and checked for porosity before having the stepped liners fitted. 

The MG guys are probably talking K series? If so, they have quite different issues. The K series uses an open deck and wet liners. Where the V8 has the bores cast into the block, machined oversize and machined cast iron liners shrunk into place, the K series has a gaping hole with 4 machined grooves at the bottom of the coolant jacket which locate and seal the liners. The head and gasket keep the liners in place and pressure on the liner seals, but the whole assembly has about as much rigidity as a politicians spine, so it's all free to weeble-wobble about enough to eat head gaskets for breakfast. The K series is a bad terrible design and needs all the help it can get to stop the bores moving; the V8 occasionally poorly cast with Rovers ageing tooling in later iterations. 

TL;DR: a nice idea, but its probably not going to help the V8 much. 

  • Like 1

Share this post


Link to post
Share on other sites

I'm not sure I would trust a screw to stay put in that environment, and the potential for making the liner shift or distort and then leak will be much greater.

Top hat liner and problem solved.

That said, I would run it and see what happens before shelling out the cash for top hatting.

  • Like 1

Share this post


Link to post
Share on other sites
Posted (edited)

I have seen an article in the past detailing a well executed liner pinning operation on the V8.

I have no idea on its effectiveness though.

Edit: I think this may have been the one https://www.scribd.com/doc/220372040/Pinning-V8-Liner

 

Edited by mickeyw

Share this post


Link to post
Share on other sites
8 hours ago, lo-fi said:

On the V8's that do suffer with liner slip, it's usually a consequence of deeper issues than just movement of the liners itself. Porosity, super thin bore casting due to core movement during casting or corrosion of the bores behind the liners let's coolant in behind them. Couple that with the seam line between liner and block being directly under the sealing ring in the gasket (that top hat liners neatly fix) and it can all add up to a bad combo if you're unlucky and have a duff one. A well executed top hat conversion will have had the bores thickness tested and checked for porosity before having the stepped liners fitted. 

The MG guys are probably talking K series? If so, they have quite different issues. The K series uses an open deck and wet liners. Where the V8 has the bores cast into the block, machined oversize and machined cast iron liners shrunk into place, the K series has a gaping hole with 4 machined grooves at the bottom of the coolant jacket which locate and seal the liners. The head and gasket keep the liners in place and pressure on the liner seals, but the whole assembly has about as much rigidity as a politicians spine, so it's all free to weeble-wobble about enough to eat head gaskets for breakfast. The K series is a bad terrible design and needs all the help it can get to stop the bores moving; the V8 occasionally poorly cast with Rovers ageing tooling in later iterations. 

TL;DR: a nice idea, but its probably not going to help the V8 much. 

Definitely was the Rover V8 engine, it referenced the Scribd article above.

If the block has no issues at the present and the cooling is up to standard, then there's no risk of a liner slipping, is that right?

 

Share this post


Link to post
Share on other sites
6 minutes ago, Gazzar said:

If the block has no issues at the present and the cooling is up to standard, then there's no risk of a liner slipping, is that right?

 

Well not no risk, but if it hasn't already slipped, I certainly wouldn't go to all that faff. It is arguable that if the block has lasted this long it is probably not one of the ones with an inherent problem.

Share this post


Link to post
Share on other sites

Interesting! I can't see that helping; liners moving being a symptom rather than the cause. Always interested to learn more, though. Agreed with Bowie, if it's not failed yet it'll probably be fine.

Share this post


Link to post
Share on other sites
On 3/26/2019 at 7:54 AM, lo-fi said:

The MG guys are probably talking K series?

The Rover V8 was used in both MGB V8 and RV8 as well as the Costello MGB V8 conversions that inspired the factory version, and they're also popular for aftermarket conversion particularly of the MGB. They're a common topic on MG forums.

Share this post


Link to post
Share on other sites

Worry about the liner if it ever becomes an issue. 99% chance you'll never have an issue with it.

Share this post


Link to post
Share on other sites

I agree with the others, if the liner's going to slip in the block, having a bolt through the bottom isn't going to save it or solve it (IMHO it may well break and wreck the engine) - I suspect there's just a load of confirmation bias going on among owners who've had it done and their liners haven't slipped so it must be good...

  • Like 1

Share this post


Link to post
Share on other sites

This all makes good sense. 

Thanks.

Share this post


Link to post
Share on other sites

Buy the engine, fit it and drive it.

While you are enjoying it, buy the bits to do the top hat mod and do it to another engine ready to drop in when it's done.

Sell the good engine you just pulled out to cover costs.

  • Like 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy