van engine rebuild

[surfergirl]

Having compression tested the engine in the van and found it to be a bit low and looked at the price of a recon engine, Ive bit the bullet and started to look at one of the spare engines with a view to rebuilding it.

Ive never rebuilt one before so I need to pick members brains on where to begin! I took the sump off the engine I know came from a Traveller and looked at a couple of bearing shells, which had fine scratches on them and the crank. Took the cylinder head off and had a look at the piston tops which are MOWOG and two have the No.2 stamped in a diamond and two have the No.3 stamped in a diamond, is this from a previous rebore?

Where do I go next, take the block to be rebored and get a new crank and oversize pistons and perhaps a unleaded head?
Will a new unleaded head fit the old block without any mods?
Any advise would be great on the pitfalls involved.
Cheers

[alex_holden]

The numbers in diamonds on the piston crowns mean they are original. If they were oversize they would have something like +20 marked on them.

I suggest you get the bores and the crankshaft journals measured to find out if they are worn enough to need machining. It may be fine with just a new set of bearing shells, piston rings and a new oil pump. (If you fit new rings without a rebore, you'll need to 'glaze bust' the bores so they can bed in.)

Depending on your driving pattern, there may not be much point in you fitting an unleaded head. I did on my cars, but then I do a lot of fast motorway miles. An unleaded head is a straight swap for a standard one (it's just a standard head that has had hardened exhaust valves and seats fitted).

[bmcecosse]

Don't worry about 'unleaded' head - it will be fine without. Can you post up picks of the bearings etc - as Alex syas - it may not need much work - just a light overhaul with new shells and perhaps rings - although a again - a picture of the bores would help us!

[surfergirl]

Thanks for that, ill take some pics this weekend, can anyone suggest where I can get the bores and crank measured in the far southwest.
Thanks

[timmo]

This was the only place i could find http://www.cornwallengine.co.uk/ when i was looking into rebore etc, didnt get round to doing anything though Im sure there are enineering places local who could do the measuring for you, if i can think of them i'll let you know

[bmcecosse]

You simply feel down the bore - to see if there is any wear ridge. the top 1/4" doesn't wear - so you compare slightly down the bore with the very top part.

[surfergirl]

o.k Ive took a couple of pics of the bores and bearings, the bores have a light wear ridge just before the top and some surface scratches in the bore. Ill try and get some sharper pics tommorow. How come a unleaded head isnt needed, will petrol additive be needed?[frame][/frame][frame][/frame]

[PSL184]

Head gasket looks to have blown in that pic above. No need for any additive or an unleaded head unless you drive many motorway miles. If just "round town" I'd save the money and put it towards the bottom end. Crank regrind, new shells, bearings etc. A local machine shop should manage that lot for about £250.00

[bmcecosse]

You can get a complete exchange crank from Bull Motif - WITH shells for ~ £80 plus post. It's an absolute bargain. I would say these bores don't look too bad - but the shell you show is a bit 'scored' - how about a picture of the crank journal - that's what matters?!

[surfergirl]

nipped down to the shed and took a couple of pics of the crank with the shells removed, see what you think. Thanks[frame][/frame][frame][/frame]

[bmcecosse]

Ooooooh yes - exchange crank required! Would be wise to fit a new oil pump - and you must check inside the oil filter casing to see if the plate and spring are present. This kind of damage can happen if unfiltered oil goes round the system. Make sure you know which bearing cap came off each rod - they MUST go back on the rod they came off!

[surfergirl]

This is quite worn I take it ! So its a rebore and oversize pistons and a oil pump and timing chain.
The bearing caps have punched dots on them so hopefully I cant mix them up and Ill check the filter as things progress, thanks for the advise.
My neighbour has recomended an engine place at Nancegollan near Helston, they rebored the engine in his morris 8, so Ill get some prices next week. The new crank and shells are a straight swop for the old one? Also the gudgeon pin holding the piston does this wear & need replacing? Bit of a can of worms this!
Thanks

[billlobban]

If you buy the exchange crank from BM its just a straight swop it comes complete with shells and thrust washers and is a really great buy. New gudgeon pins come with your new pistons. You might also want to compare the price of the rebore complete with pistons and just the rebore price (you can get pistons from lots of suppliers)

[bmcecosse]

I really don't think you NEED a rebore and pistons...... Some more pictures would help! As Bill says - the crank is a straight swop

[MarkyB]

Is the ridge at the top of the bore deep enough to catch you fingernail on?
That's the "rule of thumb (finger?)" for looking at bore wear.
If it isn't new rings should be fine.

It's the condition of the shell in the first picture that suggests the oil hasn't been filtered.
It should be smooth and even as it gets the most oil, your looks to have "picked up" normally seen on pistons and bores that have been overheated, often 2 strokes.

I'm guessing that some aluminium from somewhere else in the engine has been circulated in the oil then smeared where to oil enters the ends.
It would be well worth taking extra care in flushing out the oil-ways before putting the engine back together.

[bmcecosse]

Can also just be an indication of having been run low on oil ............