New rings and hone or not?

[englishmaninwales]

One for the engine builders please. Second opinion needed.

Engine is dismantled and cylinder head is away for repairs. Bottom half has been dismantled to fix the leaking rear crank rope seal and replace timing case castings.

Measured up (not by me, but a competent engine builder) and the bores are well within tolerances for a 030" overbore. Previous honing crosshatching is still partly visible. Pistons still look new.

Fits with the history as re-bore was only 9000 miles ago (in 1991) so barely run in. Good pre-dismantle compressions, no blue smoke and oil consumption was ok

The advice I had was that it would be ok to simply refit the pistons with the existing rings. I feel happy to go with this advice but should I consider re-honing and new rings?


Thanks

Malcolm

[john.p.clegg]

Malcolm
Stop fretting and put it back together...

John

[512BB]

I to would just put it back together, but what I would have done on dismantling, was note where each piston and all rings were, relative to their respective bores, and replace in exactly the same positions.

That may or may not have any relevance, but it is just the way I do things.

Leslie

[englishmaninwales]

Thanks for the advice.
Leslie, the ring position was my concern. But then I guess they probably move in service.
John, but I enjoy my hand wringing

[john.p.clegg]

Space the ring gaps at 120 degree intervals...

John

[reb53]

Spacing them around will make you feel better but everything I've ever read says they move around of their own volition at different rates.
So the way you leave them will not be the way you next find them.
I once heard a figure of once per minute per thousand revs, but that sounds too much to me, and I'd suspect the amount is dependant on all sorts of design, and wear, parameters.

[bill308]

Having gone this far, an barring any information on clearances, prior cylinder sealing condition, and what came from where, I would hone and replace rings as a minimum.

Bill

[types26/36]

Having gone this far, an barring any information on clearances, prior cylinder sealing condition, and what came from where, I would hone and replace rings as a minimum.Bill

I agree, if history is not known...............its a lot of work to do it later when you had the chance now.

[john.p.clegg]

"Fits with the history as re-bore was only 9000 miles ago (in 1991) so barely run in. Good pre-dismantle compressions, no blue smoke and oil consumption was ok"

John

[bill308]

If it were my engine, I would also check the bottom end carefully, replace the early 116E rods to the 125E's, use ARP bolts throughout, check and probably replace main and rod bearings, and of course all gaskets. Where you happy with oil pressure?

Positively identify and mark TDC, to a high degree of precision (+/- 1 degree).

What's the status of the water pump assembly?

How's the distributor and its bushings? Have you switched over to pointless ignition and do you know the timing advance and are you happy with it?

Check the clutch friction plate and TO and pilot bearings.

Check input shaft seal of the tranny.

Bill

[alan.barker]

is it possible to convert from rope seal to rear lip seal.
Could be a good idea.
Imho for the pistons Deglaze/Hone and new rings
Alan

[rgh0]

For the conversion to lip seal - new crank new rear seal carrier and new sump. The sump is the hard bit to find - look for old Mk2 cortina engines on ebay for the sump and a spare block

Personally I would just put the pistons and rings back if the bores were good and the ring and piston wear minimal.

cheers
Rohan

[david.g.chapman]

I had a problem with breaking top piston rings - eventually put down to having too large a gap between the grooves and the fitted rings.

The top ring would prematurely wear thin - perhaps due to excessive rotation speed - and then break.

Last time I made sure the ring to groove clearance was well inside the top limit with new pistons and rings. I would check your measurements with what you have and make sure they are good too - then replace if required.

Dave Chapman.

[englishmaninwales]

Ok thanks for all the advice, as usual, a very helpful forum.

For the conversion to lip seal - new crank new rear seal carrier and new sump. The sump is the hard bit to find - look for old Mk2 cortina engines on ebay for the sump and a spare block


cheers
Rohan

Yes, I considered doing the crank conversion as well, especially as my block is an early 3020 Mk2 but with round caps / 4 bolt crank, but later push fit pickup/return. I was outbid on a lip seal Mk2 sump on ebay 2-3 weeks ago, went for ?225!