Topic: Engine reassembly

[JHansen]

OK, I'm being paranoid here right???!!!

My new pistons finally found their home in the barrels of my 400f tonight. I'm getting much closer to being finished! The whole motor went together like butta (30 pages of hand written notes, about 75 pics of disassembly, and 3 shop manuals, I should be ashamed if it didn't, right!?) Shifts thru all the gears perfectly, and turns over at the crank very smoothly.

Only one dark spot... After my barrel was put on, I turned it over and now am hearing the faintest grinding noise that seems to be coming from all 4 cylinders. I'm pretty confident I didn't break any rings putting it together but if I did, would I know it? I'd think I'd have heard them breaking as I was sliding it down. This is my proverbial engine rebuilding cherry pop, so I'm a bit unsure what to expect here. The motor has all new pistons, rings and freshly bored/honed barrels. So you tell me, am I being paranoid?

If so, it's cylinder head tomorrow night, It's about 3:30 am here right now, and I'm just too tired to do any more work on it tonight. May have to cut out of work early tomorrow!

Also, incidentally, what purpose do the 4 rubber seals that go round the underside of the barrels serve?

Thanks! John

[lassenc]

Did you oil it all before assembly?

There will always be a faint sound of the friction between the barrel and the pistons.

Do you have the correct clearance on barrel/piston?

[JHansen]

Barrels were heavily oiled before assembly

Machine shop setup the rebore with my new pistons, I have no doubt in their accuracy (famous last words, right!)

And yes, the noise is very faint, but louder than it was during disassembly, though I think that the fresh rings and cylinder work are accounting for that. As noted eariler, in turns over really smooth, and the noise goes away completely for a few degrees at both TDC and BDC

I cannot see where a brokern ring is gouging any of the cylinder walls

Thanks!- John

[lassenc]

If it's not a huge deal, off with the cylinder and check.

Maybe take out a piston and put it in the cylinder to check if it is the same sound

[hcritz]

Hey J...
There will be some noise from the new rings and the honed finish of your new bore job...
Sounds sort of like a piece of sandpaper in the cylinders.

[JHansen]

Bingo- that's a perfect description of it- thanks!