re-ring or swap engine?

[anonymous-user]

My 1994 1.8 Eunos is burning quite a bit of oil at high revs, so I thought I would strip it down to see what state it was inside - I removed the head today and there is a lot of burned crud on the piston tops that flakes off if you rub it, and cylinder #2 has some vertical marks on the cylinder walls, deep enough that I can feel them but not enough to really catch a fingernail in. They seem to be evenly spaced all around the bore about 1 cm apart, but only on cylinder #2, the others have no scoring.

So do I rehone the bores and fit new rings - will that be enough to remove the scoring? And would I need to fit oversized rings or does it need to go off to a machine shop to be rebored and then have oversize pistons etc..? At which point it will be far easier and cheaper to get a decent used engine from someone like Autolink UK.

So not quite sure what to do, the engine is coming out either way but I wonder if it makes sense to just get a used engine and save all the messing around.

If its just a case of honing it and then using either standard or slightly oversize rings then all good and I'll give that a go, but its usually not that simple

[steveo3002]

sounds like you might get away with a hone and re ring , you would fit standard size rings (after checking its not been rebored before)

i think the mazdas suffer from stuck rings , seen a few threads about it

[Tango13]

Tricky one.

If you rebuild your current engine you know it's been built properly but a second hand engine will always be an unknown quantity. It may be cheaper to buy a good second hand engine but if you go that route it would be wise to keep a few £££ by just in case the engine isn't quite as good as you hoped or spend the extra on a rebuild and know the engine is good.

Personally I'd rebuild.

[anonymous-user]

Yes that was my initial thoughts - rebuild the current engine as I know the rest of it is solid - but the vertical score marks in cylinder #2 have made me stop and rethink. I've done most jobs on an engine but not to the actual pistons/bores (beyond removing the pistons on an older 1.6) so I wasn't sure whether honing them would be enough to remove those score marks, or whether in doing so that I might oversize the bore too much.

[227bhp]

It's impossible to say without it disassembled and in front of you, so do that and take it to someone who knows what they are doing (trusted Automotive engineer/machineshop).
You can't fit oversized rings to standard sized pistons, the pistons have to fit the bore precisely otherwise it will slap like a Mofo at the very least.

[anonymous-user]

If it requires something like rebore + larger pistons then I'll just get a good used engine instead, but if I can hone it and re-ring then I want to do it myself and learn how to do it.

[PaulKemp]

You won't hone it at home, at best it'll be a heavy deglaze.
I have deglazed and re-ringed an engine, two issues, correctly gapping the rings realy needs a proper ring gap tool, I was lucky gaps were in tolerance straight out of the box, second was properly cleaning the block of all honing stone dust and bore metal

[anonymous-user]

I think the best thing then is to strip the block and take it to a machine shop that i've used before so they can have a look and see if they can clean up the bore without requiring larger pistons etc...

Much as I'd like to do it myself they can clean it etc.. properly too, and skim the head for me while they're at it. If they say it's no good then at least I've not wasted the cost of the tools , rings , gaskets etc..

[227bhp]

JimSuperSix said:

I think the best thing then is to strip the block and take it to a machine shop that i've used before so they can have a look and see if they can clean up the bore without requiring larger pistons etc...

Much as I'd like to do it myself they can clean it etc.. properly too, and skim the head for me while they're at it. If they say it's no good then at least I've not wasted the cost of the tools , rings , gaskets etc..

Think again if you believe they will clean it thoroughly and you'll trust it's been done and just assemble it.
They should be able to tell you before they do any work if it will be successful, not after unless it's really borderline or they CBA to measure it.

Very strange how you feel you have the ability to hone a block, yet not clean it. That's a bit like the 17yr old apprentice painting the Sistine Chapel ceiling and then getting Michelangelo to clean the floor afterwards.

[anonymous-user]

Very strange that I would expect a machine shop to be able to clean a block better than I can do on the driveway? Hmm..

BTW I'm not interested in your opinion of whether you think I can do certain things (smiley face or not), I was just after some info about how these things work, which I want to do myself and learn from. If I mess up the engine, so be it, it's a hobby and I am quite prepared to make mistakes.

Edited by anonymous-user on Monday 29th February 09:56

[one eyed mick]

If you are going to pull the lump out and strip it , in my op it would be stupid just to hone i go first o/s and new pistons ,all new brgs and oil pump --- new engine much better than lots of labour for a rering

[anonymous-user]

So I gave in and just ordered a good used engine

At least I will have almost a complete spare parts engine, and I still get the fun of swapping over all the shiny bits and putting the new engine back in without the possibility of it being a complete waste of time & money.