.020 or .040 over.....

[Guest]

Hello

I was able to get the heads off the Stag
without any issues (miracle!!). Now I am
looking at the bores and well the are rusty
They must have sat with some water in them

The are going to have to be overbored. Does
anyone have any thoughts on how far over to go?

Is it better to go .020 or .040.

Thanks
Joe

[GDPR]

Go for the smallest bore first to give your block more life - your machine shop will advise...

[flying farmer]

If you have a bore that is seriously rusted it is possible to get liners fitted. I had a block with seven good +20 bores and 8 good pistons and it worked out cheaper to liner the one bore than a full rebore and new pistons
Neil

[Guest]

If you have a bore that is seriously rusted it is possible to get liners fitted. I had a block with seven good +20 bores and 8 good pistons and it worked out cheaper to liner the one bore than a full rebore and new pistons
Neil

Unfortunately I have at least three cylinders that are fairly
rusty. I can't see all the cylinders since I have not disassembled
the bottom end. I was going to get the rebuild kit from Rimmers
but I haven't decided on the over size just yet

Thanks
Joe

[wilf]

Get your machinist to assess the minimum overbore that will clean all cylinders up, then buy your parts to suit.

[dasadrew]

I was going to go down the rebore route until I found out that the aftermarket pistons are not the original domed type as I had in my engine. Ended up relining 8 bores and re-using the original pistons with new rings. Domed pistons aren't available in oversizes (anymore). Liners are readily available.

[Guest]

I was going to go down the rebore route until I found out that the aftermarket pistons are not the original domed type as I had in my engine. Ended up relining 8 bores and re-using the original pistons with new rings. Domed pistons aren't available in oversizes (anymore). Liners are readily available.

What is the issue with not having domed pistons?
I noticed the top of the existing pistons are concave.

Are the aftermarket pistons flat on top?
Does it make a difference?

Thanks
Joe

[dasadrew]

What is the issue with not having domed pistons?
I noticed the top of the existing pistons are concave.

Are the aftermarket pistons flat on top?
Does it make a difference?

Thanks
Joe

Are the aftermarket pistons flat on top? Yes. Well, some say "dished" as opposed to domed.

Does it make a difference? Yes. See Neil's post #36 in this thread
http://www.stag.org.uk/forum/showthr...ed-some-advice

4 types of pistons originally fitted:

155473 Mk1 -flat/dished (replacement type from e.g. Rimmers)
160010 Mk2 -domed
157894 Mk1 USA
159792 Mk2 USA

[Westfaling]

Joe
Sounds like you've got USA spec engine - lower compression. Mine was like that - it's a 72 Federal Car . Sorry about the blurry picture. Second picture has new County flat top pistons.
Nick
Piston.jpgflat top.jpg

[Guest]

Joe
Sounds like you've got USA spec engine - lower compression. Mine was like that - it's a 72 Federal Car . Sorry about the blurry picture. Second picture has new County flat top pistons.
Nick
[ATTACH=CONFIG]18797[/ATTACH][ATTACH=CONFIG]18798[/ATTACH]

Hi Nick

I have a 73 us spec
I have pistons like the one in your first photo

My bores are quite rough and I won't really know
The damage until I have everything apart

I may not even be able to get out the pistons without
destroying them.

I may have to go with new liners

Thanks
Joe

[Guest]

That's a good thread. Thanks!!

[Goldstar]

I may not even be able to get out the pistons without destroying them

Fill the bores so they can soak in diesel or an acetone and ATF mix or Kroil if you're in the US before you go mechanical, I'm doing the same with a seized engine right now-diesel first.
Good luck

Paul

[Guest]

Fill the bores so they can soak in diesel or an acetone and ATF mix or Kroil if you're in the US before you go mechanical, I'm doing the same with a seized engine right now-diesel first.
Good luck

Paul

I had them soaking in all kinds of products for weeks before I had the heads off

Once I have the engine out and on a stand, I will be able to take the crank out and
get underneath as well and can get some penetrating oil under the pistons. I may heat
the block (gently) and try freezing the pistons to see if that helps.

Gentle mechanical first til the patience runs out

Thanks
Joe

[Goldstar]

Good luck