Engine rebuild 2.5 to 2.8 ltrs

[Patrick]

Well there are no cracks which is good news! But the guy at the shop refused to just clean it, check it was straight (and skim if needed) without overhauling the whole head which would cost £500 - £600!

So I'll try a different shop as I can't be bothered dealing with arrogant prats that won't listen to what the customer wants and telling you will do a crap job if you do it yourself.

[MartinClan]

Originally Posted by Patrick

Well there are no cracks which is good news! But the guy at the shop refused to just clean it, check it was straight (and skim if needed) without overhauling the whole head which would cost £500 - £600!

Vote with your feet and go somewhere else. There are plenty of places (round here there are anyway). Most of them are small outfits but seem to do a good job. Best to go by recommendation if you can.

Robin

[Patrick]

This place was recommend to me! I've got the name of another to try now


Puller-me-jig in place. The metal plate is bolted to the bit that needs to come off. In the middle a long bolt (out of an M52 block!) and a nut. Theory is you do up the bolt in the middle and it pops off.

The metal is already bent from the first time it wont done up (it moved about 1/2 mm)

Carefully the middle bolt was done up until it started pulling off.

and here it is finally!

There were tiny amount of rust underneath which is what was causing it to stick.

Needs a good clean out and polish before test fitting on the M52 crank.

[alackofspeed]

I don't know where in Hampshire you are, but I thought I'd mention 4 of my friends have received good service from:

http://www.magnumengines.co.uk/

[Patrick]

Thanks for the link - I'm near Winchester, I'll check out Saunders Motor Works Ltd in Southampton which I've been recommend first as they are a bit closer. If I don't have any luck there I'll try Magnum

[Patrick]

M20B25 piston test fitted with M20B20 conrod and M52B28 crank! Moves well.

Piston / conrod / crank combo at top dead centre - looks good

[GreatOldOne]

You think that's good - wait until you have them all in and then give it a spin - it's hypnotic...

[Patrick]

Its going to need a thicker head gasket that standard. Still trying to figure out much bigger at the moment!


Crank spacer taking shape on the lathe

One step left is to machine down the spacer to the correct size - about 18mm

[Patrick]

I've finished the crank spacer:


Spacer machine down to size, about 17.90mm with in 0.1mm of the original.

Cam belt pulley test fit, this a very tight fit so it will need the "the tool" to get it back off again.

As the M52 crank nose it a bit longer than the M20 the washer in the front doesn't sit flush.

Washer in the lathe, need to take about 1.25mm off giving 0.1mm space between it and the crank nose.

Finished off and the edge smoothed off

Test fit of all parts on the M52 crank.

Comparison: M52B28 crank and the front and M20B25 at the back

[Patrick]

Cleaned up all the pistons today, but managed to snap one of the piston rings in the process - doh!

Andy, the chap who came up with the conversion several years ago has recommended I use the standard head gasket with this conversion!

One more discovery after examining the head, its not quite straight - its warped ever so slightly towards the front where the thermostat sits. Check with a steel ruler, but to be 100% sure I used the lathe bed which confirmed it. Off to the machine shop with the head next week then!

[Patrick]

Silver is so last month, so blue it is this time!

We used red hamerite on the exhaust plugs and those didn't discolour until we welded something on it - so it seams heat resistance enough!

The hammered blue looks great out in the light.

Oil pump disassembled and cleaned. It all looks fine nothing really worn so no need to replace it.

The parts slot right into place, covered in assembly oil. This stuff is thicker than normal oil and kinda sticks to everything. Should help keep everything lubricated on the fist run.

The filter element has a few hardended clumps inside it but nothing major!

[Patrick]

Got the head back from the machine shop on Friday (the place in Southampton were very good and friendly (if a little bit odd), unlike the first place!), they took 4 thou off to remove the warp:

Starting a bit of valve lapping

2 down only 10 to go!

All the valves boxed up and ordered

Throttle body attaches here, its been ground a bit larger - more pictres to follow on that at some point

Valve springs - the larger one has shrunk 2mm over the inside ones and new springs.

All valve lapped in - a simple short sentance that will take you hours and hours, especially if you have pits on the valves like we did!

A nice mat grey colour is what your after!

The valves all have a nice mat dull finish on them as well.

Valve stem oil seals going on - a size 11 socket bit proves to be exactly the right size to push these in place.

One at a time the new schik valve springs go in, putting the colletes back on proved to be a very fiddly proceedure!

All springs now in place!

All cleaned up - the head needed a 4 thou skim to take the warp out of it.

[GreatOldOne]

Bling!

Very nice. Going for a colour cor-ordinated block, eh? (You're doing the sportster blue as well, IIRC...)

[Patrick]

Yup, that and I was not impressed with the silver finish. Looked nice at first but looks kinda dull - I was hoping it would set to a nicer finish after running the engine! The head will say in Ali and the intake / rocker will say black / ali

I might pull the callipers off and do those blue as well seeing as the rush is showing through the paint already.

Thinking of doing the sump yellow

The e30zone guys didn't think doing the valves with the aid of a drill was a good idea but seems to have worked OK. Took all day doing it with a drill. We'd have been there all week if we did those by hand!

[MartinClan]

Hey Patrick

That's a really clean workshop you have there - great for engine preparation and other stuff

Looking good anyway. Is that the first engine you have rebuilt? I find it is one of the most satisfying jobs to do.

Robin

[Patrick]

Thanks (that's my dad's work shop) I though it best to do all the head work inside. Won't be doing the rest of the assembly there as lugging the engine upstairs will be a pain in the back (and not back side this time )

Yup it's first engine I've rebuilt - I will be much relieved once it's running again!

[GreatOldOne]

Originally Posted by Patrick

Thinking of doing the sump yellow

Nah - CBS do some lovely hot pink enamel... That'd look fab... (Not)

Originally Posted by Patrick

The e30zone guys didn't think doing the valves with the aid of a drill was a good idea but seems to have worked OK. Took all day doing it with a drill. We'd have been there all week if we did those by hand!

Yeah - I got a drill powered lapper to do mine. It attaches to the drill, but instead of just wizzing round and round it steps the speed down and spins about half a revolution one way, and then reverses. 20 secs in one position, move 90 degs and another 20 seconds in the new positon, and you're done. One of my better ebay purchases!

I remember doing an old rover V8 with my mate one time, and we didn't even bother using the stick - just stuck the valve in the port and then attached a cordless drill to the stem on the other side. Worked a treat!

[Patrick]

hmm, guess it would have been better to do it that way (I did alternate directions while doing it) next time... (maybe not...)

[Patrick]

Camshaft inserted

New oil seal and o-ring for camshaft

Rocker shafts and rockers on their way back into the head - the head needs to be propped up so there is room for the valves to open as the last rocker needs the camshaft rotated to slide in. Also make sure the rocker shafts are at the right angle before rotating the camshaft otherwise its not easy to move the into the correct place.

Both rocker shafts in and the clips that hold the rockers in place. The spray bar as also been mounted.

A closer view of the assembled head

Everything now in place on the head, it just needs the rocker cover put in place to shield the inside from dust.

[Patrick]

New parts! Conrod bolts, main bearing shells, big end shells, water pump, cam belt and piston rings.