17 replies to this topic

[dow62]

Work done at machine shop, done about 300 miles since rebuild , engine a bit of a smoker, more running in miles needed ? Done about 100 miles on Halfords classic oil after rebuild then changed to Valvoline 20/50.

[Dusky]

It should not smoke after a rebuild

[Blatherskite]

What about valve guides and seals? Did you get those done as well?

[brownspeed]

+1

[dow62]

New guides, valves, head skimmed , block re faced, honed, new rings,  crank polished, new mains, big end shells. Measured and deemed ok by machine shop (good name recommended) Yep, know it only should have smoked on initial start up.

[carbon]

Did you fit new valve guide seals as well?

 

And was the clearance of the new piston rings in the ring grooves under 5 thou?

[Stiggytoo]

You say new rings. But has the clearance been measured. It may all have to come apart again to get it bored out and done properly.

[KernowCooper]

You say new rings. But has the clearance been measured. It may all have to come apart again to get it bored out and done properly.

Exactly my thoughts was it measured to see if it was acceptible to have a hone and new rings, and re carbons question what was the ring gaps?

[Spider]

Sorry, I don't know what Halfords Classic Oil is, but you need a light, non-friction modified Oil for around the first 300 miles. Penrite have a Running In oil, it works a treat.

 

Did it smoke right from the very first start and not settle or gradually get worse?

 

Also, when you got it running, did you load it up or let it idle?

 

I'd say if it's still smoking by now, almost certainly it will have to come apart again.

Edited by Moke Spider, 25 April 2015 - 09:35 AM.

[dow62]

As stated measured and given the ok by machine shop.(who supplied and fitted the rings to the pistons) Hind sight says should have had it re bored to +60 (1310 now). Not belching smoke, smoky on start up clears when hot, unless been idling for a while. Have another Mg Metro engine, might drag it out and prepare it for a winter change over. (including rebore Lol) Just live with this summer.

Edited by dow62, 25 April 2015 - 10:52 AM.

[Steve220]

I take it that it's blue smoke?

Sounds like stem seals leaking to me.

[whistler]

Does it smoke on the overrun? If so then valve stem oil seals. I note that only inlet valve stem seals are supplied nowadays so maybe the assembler didn't fit exhaust valve seals.

It seems that A series engines always had both inlet and exhaust valve stem oil seals for 40 years or so until someone decided that the exhaust ones weren't necessary. I've just rebuilt a Cooper head and fitted the old exhaust seals back on as well as new ones for the inlets. Haven't started it yet! ........fingers crossed.

[dow62]

Correct whistler ! only four supplied and fitted to inlet valves. Plenty to think about.

[carbon]

Dow, I would recommend fitting valve stem seals to the exhaust valves as first step.

 

I have had similar issues with smoke on start-up, much reduced when I fitted exhaust valve stem seals. If you still have the old inlet seals which were replaced then these will be fine for the exhaust.

[dow62]

Seems the sensible thing to do carbon, rather than jump in feet first ! Simple things first.