Engine rebuild questions (pics)

Post by **timmo** » Fri Jul 10, 2009 5:43 pm

The engine came in bits in boxes! with the traveller

Started sorting it out see whats missing etc and started assembling it. The pistons look like they had new rings on, so i thought i'd check the gaps, so put the top ring in the bore and it seems to be a large gap...1.5mm about 60 thou according to the Haynes manual it should be between 7 and 12 thou?? So i dont know if the P.O. has filed too much off, or the rings came like that..if so why such a big gap? is this ok?

Heres a pic of the ring in the bore

ALSO...found these bolts..they have 2 holes through the head (flat to flat) anyone know where they should go? or are they just some extra bolts?

AND....Does anyone know where these springs a supposed to go?

Cheers Tim

Post by **aupickup** » Fri Jul 10, 2009 6:12 pm

the 2nd picture are i think the rear crank shaft seal area the holes are for wire to pass through and be tied off so to speak

this was normally factory set

Post by **MarkyB** » Fri Jul 10, 2009 6:12 pm

I'm wondering if it's been rebored then the owner found out how much a set of pistons cost and baulked.
What is the fit of the pistons like?
The bolts have been drilled so they can be wired (racier alternative to locking tabs)
I'm just putting my engine back together and I don't recall having to unwire any bolts but I have a suspicion that I've seen 3 bolts wired together somewhere.
Sorry I can't be more help.

Post by **timmo** » Fri Jul 10, 2009 6:24 pm

Could be from the crank...Im missing the crank (post on wanted) so may well be from something there....The pistons without the rings on are a good fit in the bores....no excessive gaps on the trust side

Post by **aupickup** » Fri Jul 10, 2009 6:59 pm

the bolts ith holes are on teh rear part of engine where the crank comes through and hold the bottom part of the rear main bearing

Post by **timmo** » Fri Jul 10, 2009 7:05 pm

Ah..yes, i know where you mean...the half round part that goes on the top?

Cheers

Post by **bmcecosse** » Fri Jul 10, 2009 9:43 pm

Hope you have that part ? Yes - that's where the bolts will be used. Ring gap - just use them and see what happens - assuming the bores are good with no wear ridge just down from the top ? Is this 948 or 1098 engine ? The tiny springs may be gearbox related - certainly not used in the engine.

Post by **timmo** » Fri Jul 10, 2009 10:18 pm

Its a 1098 engine...Yes i have the part, just haven't got the crank!! There is a ridge, but how bad before it needs reboring? Haynes manual says ok if when the bare piston it in the bore, you cant get a 10 thou feeler down the thrust side? and the top ring should be stepped to allow for the ridge?? not sure how you do that!?? What is the best thing to do??

Post by **bmcecosse** » Fri Jul 10, 2009 10:49 pm

The top rings would need to be bought with the 'step' in them already. Nothing you can do to them now. You should ease the lip away with emery paper - and scuff the bores in a criss-cross pattern with the emery paper too!

Post by **timmo** » Sat Jul 11, 2009 7:04 am

OK bmc, thanks. Who sells the stepped rings and can i buy just a set of top rings or do i have to get a complete set of rings?

The larger spring in the pic...is that something to do with the oil filter assembly??
Cheers Tim

Post by **bmcecosse** » Sat Jul 11, 2009 9:44 am

You cpuld try to get a set of top rings - but I think difficult without buying a complete set. Cords made ring sets - sometimes come up on ebay - dunno if still available new. Yes - you could be right about that spring - could well be for the filter - well spotted!

Post by **katy** » Sat Jul 11, 2009 3:38 pm

Push the rings down to where there is less wear in the cylinder, then check the gap.
In this country we use a "ridge reamer" to remove the ridge from the top of the cylinder.

Post by **timmo** » Sat Jul 11, 2009 4:21 pm

Did that...still large gap

will have alook tomorrowand see how much of the ridge i can remove

linearaudio · Post by **linearaudio** » Sun Jul 12, 2009 7:47 am

Frankly, with your box of bits and uncertainties, I would put out a wanted ad for a complete running engine!
You could be a long while removing a ridge with emery paper, even using a rotary hone can take some work! Also as the bore obviously has wear in it, it will in all likelihood therefore be oval, that ring gap is huge, you have to find a crank, set of shells (guessing) and there are concerns about that top ring not being a ridge dodger.

A new set of rings, shells, gaskets, and crank for a worn engine versus a known complete running lump from an ad...... Don't know about your neck of the woods, but I have heard they are almost littering the roadside in parts of Scotland

Post by **bmcecosse** » Sun Jul 12, 2009 10:08 am

Not up my way they aren't! Although - I do have a very good 1098 engine for sale!

Post by **timmo** » Sun Jul 12, 2009 4:49 pm

Had a play today, smoothed out the lip...and a friend cleverer than me

had a go at stepping the top ring, well more of a slight chamfer to the top edge in the lathe ....Piston goes to the top of the bore and beond with no problems. Im going to get a new set of rings out of piece of mind see how the gaps compare also noticed that one of the rings was broken anyway

linearaudio · Post by **linearaudio** » Sun Jul 12, 2009 7:00 pm

timmo wrote:...and a friend cleverer than me had a go at stepping the top ring, well more of a slight chamfer to the top edge in the lathe ....

And a damn sight braver than I would be!! Sounds like a handy friend. Hope it all works out OK!

Post by **timmo** » Sun Jul 12, 2009 7:09 pm

Think it will...tried a piston with a standard ring on first and was catching on the lip...the chamfered one didnt..then after smoothing out the ridge it was perfect! .. He has his uses LOL

Post by **bmcecosse** » Sun Jul 12, 2009 8:55 pm

Make sure you know what bore size the engine is - before ordering rings. Also - inspect the piustons carefully - if the ring grooves are wide and/or the 'lands' are damged- there really is no point fitting new rings - it's going to need pistons and in that case - may as well get it rebored!