block relining

[Pirvu Eugen]

Hello!
Somebody from you has tried to reline an scored block?
Is verry popular here in Romania to do this.... but dont know iff i should worry or not at 400hp.
Block with no wear i cant find.
What do you think?
Thank You!
All the best!
Eugen

[quattronutter]

if there is no bore wear and all bores are within their limits then it should be fine,as long as there is no scoring,best to have it checked by a machine shop if your in doubt

[Pirvu Eugen]

Thank You!
Mi bores have the specific wear at ~1 cm down and the wear is 0.15-0.17mm difernt between the cylinders.
The wear is too much for just rehone.

[gnutz2]

You need a re-bore then.

Go for +20thou (+0.5mm) and some pistons of your choice.

[Pirvu Eugen]

This is what i was afraid..
Pistons are expensive.
What pistons should i use if i have no other solution?
Relining is not good?
Thanks!
Eugen

[twoqu]

At the end of the day it comes down to cost and the expertise of the machinist.
Liners are cheap compared to pistons, but the necessary machine work to fit them often makes it more expensive than a normal rebore and oversize pistons.
You usually get charged per cut. They don't bore it out to the o/d of the liner straight away. So you have multiple cuts X whatever they charge. You then have to have the liners pressed in and the tops machined to deck level. They then have to finish bore to desired size and finish.
Obviously, I don't know what labour rates are like in your country, but I was looking to have a diesel block relinered back to standard size 81.01 and it was more expensive for the machine work than to have the block rebored and oversize pistons. This was with pistons at £150 X 5!
So it all comes down to economics I guess. Mechanically its a reasonable solution.

[Pirvu Eugen]

i have the machine shop...is free for me the labor...
The question is iff is a reliable option or not?
i dont whant to distroy the engine.
i have torque plate also...
What do you think?
I should try or wait money for pistons?

[Pirvu Eugen]

the only costs involved for me are the new liners wich are about 25 euro each. but this will be an 400hp engine...
What to do?
Thanks!
Eugen

[twoqu]

Well its certaintly more economical than new pistons. The end result will depend on your ability as a machinist. I can't see why a linered engine would be any less reliable than an unlinered one.
What is the supply of used worn blocks like?

[Pirvu Eugen]

Sory didint understand the question? Suply for old blocks

[twoqu]

Can you get another worn block cheaply? As machine time costs you nothing, you can practise on another block. That should give you confidence to machine your own one!
Two factors are going to be the type of liner and the wall thickness. Were you going to use a flanged liner with a larger diameter at the top or just a normal straight one?

[Pirvu Eugen]

I have 3 blocks. 2 3Bs dismanteled today and 1 AAN. All are the same.
Good point about test.
I have done 1 AAN and is ok till now, but is running stock, not 400hp.
Still no problems with that after 30k km.

[Pirvu Eugen]

I have used the staright ones pessed down.
Looks like you have alot off knoledge abou this.
Can You please tell me how will be the best?
You know some special materials for the liners?
Thank You!

[Pirvu Eugen]

You recomand a thickness for this?
Between the bores is 7 mm. how thick should be the liner?

[twoqu]

I have forgotten most of it!
Anyway, you seem to have answered your own question. You have done one before and it has lasted 30KM. If you have three blocks available then if you linered them all back to 81.01 it would cost what, 375euros. Lets say they all lasted 30KM. Thats not a bad return for your money.
Perhaps just liner the two 3b blocks. If something happens to one, you still have the other! Total investment 250euros.
Last century, I used to play with other engines like the Rover V8. These had porosity problems and it was common to use flanged lines. This also provided a stronger deck surface as the block was alloy. I would stick with what you know!