Early 1.9 to 2.1 conversion - stop me if I'm being stupid!

[123-jn]

So from what I understand head still attached but loose around all but one stud. I would forget trying to get the stud out they take some doing!!! Lots and lots of heat with a torch around the threads and the casting where they are fixed in. When I took mine apart there was a build up of brown gunge around the studs making them reluctant to come through the holes. I used two wooden wedges cut from some soft wood and hammered them into the gap between the head and case, slowly slowly tap tap and hey presto head comes off with brown gungy sludge alround the stud. If the liners start to follow the head insert a nice big screwdriver onto the liner lugs in the centre between the cylinders. If you lever against the head use a sliver of wood again so as not to damage the face. Once the cylinder liners are free of the heads keep knocking in your wooden wedges, OFF WITH HER HEAD.
If you do have to remove a stud, lock two nuts together on the thread then hold lot s of pressure on the stud anti clock with a large wrench or stilson. Mean while use a gas torch or blow torch pointed at the case around where the stud goes in continue to spray plus gas and re apply heat, eventually it will start to smell very hot and smoke as the heat spreads through, at this point increase the pressure on the wrench , the stud will begin to twist with the pressure as its only thin, dont over do it. Once it is hot enough it will suddenly go with a creak, more plus gas and windy windy quicky. (could take over 5 mins of heat)
Good luck (I had to change 6 studs on mine!!!)

[CJH]

So from what I understand head still attached but loose around all but one stud. I would forget trying to get the stud out they take some doing!!!

Yes, that's it. I've tried heat and I've tried wedges, but it won't budge. I spoke to someone at the weekend who said it has to be a very hot propane flame. I'm using a butane/propane mix canister, and I have to admit it's not giving a very clear tip to the blue part of the flame. Would a propane flame really be any hotter?

Are you sure that twisting the stud won't help? I was banking on it twisting a bit, so that even if the bottom end in the case stays put for now, the top end might just turn enough to crack the corrosion at the head end. As I see it, if I try to turn the stud and I end up either mangling the threads or snapping them off, then my options would be to i) drill through it, ii) cut through it at the joint between the case and the head. It's a narrow gap, but definitely wide enough to get a cutting disc in there.

[123-jn]

Have you tried using welding rod or steel wire to work away at the corrosion around the stud, trouble is you will have the threaded bit sticking out and this is almost as wide as the drilling whereas the stud is much thinner. The secret is movement will the stud move back through so the head is flush? Have you hit the head both sides with a wooden mallet or rubber hammer to shake it a bit sideways, you can hit it quite hard without damage. The corrosion is a sort of rusty crunchy deposit caused by rust from the stud and inadequate antifreeze leaving a sludgy mess, this hardens with heat cycles but it will loosen up, I have to admit to hitting mine a good few times each side and even a bit from below and above to loosen the corrosion , using a lump hammer and a softwood block, Then wedges and eventually some woodenpads of 4mm ply and a 24 inch bar. Just take it steady but dont be afraid to hit it and prise it. My right hand head had 2 lower centre studs gummed up like this and the front lower stud. the rest were free ish. (the flame was for getting the stud removed from the case not getting the stud out of the head ) keep applying plus gas or parafin to the top of the stud where it enters the head drilling and use the soft hammer whilst praying . hit left hit right hit up hit down and continue then more wedge the perhaps a judicious use of crow bar with wood blocks to protect the surfaces.

[CJH]

Well it was supposed to be a winter project, and since summer's definitely over I'd better crack on! The head still won't budge from that last stud, so I'm going to take it to an engine shop for that, and also to get them to check over all the bearing surfaces etc.

I've been taking a look at the bits that I've disassembled, and using Silverbullet's handy little page for WBX fans I've been able to make some basic measurements to check what sort of engine it is. The stroke seems to be 76mm and the bore seems to be 94, so that confirms it as a 2.1. Looking at the pistons, the measurement from the top of the piston to the bottom of the second ring seems to confirm them as MV pistons.

So, given that I'll be mating this engine up to my existing carb and distributor setup, what will be the difference between this lower compression (9.0) configuration and, say, the same crank, rods and heads but fitted with DJ pistons (10.5 compression ratio)? Does all of this difference come from the piston shape, or is there also a difference in the heads between MV and DJ, meaning I can't mix and match? I see from that WBX page that the DJ uses higher octane fuel, and I guess that might be related to the compression ratio.

Basically, what are the pros and cons of an MV versus a DJ when installed under a 2E3 carb? Can I convert my MV to a DJ while I'm rebuilding it, and is it worth it?

[Atomic]

MV and DJ heads are the same. Difference is in the piston only. Higher octane requirement is because of the increased compression ratio.

[CJH]

Thanks Atomic

Any thoughts on whether DJ pistons would give more power and/or torque? Any other advantages or disadvantages? I'm not looking for excuses to spend money, but if there are clear advantages to going with DJ pistons now is the time to consider it.

[Atomic]

Yes - DJ pistons will give more power.

[CJH]

OK, thanks. I can see from that WBX page that the difference in power is quite significant (and also the torque), but I wonder how much of that is down to the injection system and especially the cat. What about fuel consumption?

I read up on compression ratios and it seems the higher ratio leads to more efficient fuel burn, so more power, lower exhaust temps etc. So can anyone comment on whether I'd notice any difference in a carbed setup? Has anyone compared a carbed DJ to a carbed MV? I guess what I'm hoping for most from this engine swap, compared to my DG, is a boost in torque. Should I bite the bullet and source some DJ pistons?

[kevtherev]

If only it was that simple.
DJ's have different cam profiles, being a effectively long stroke engine.
The extra power does not just come from a bigger squeeze, but a longer suck and blow
The DJ pulls in a bigger fuel/air charge and yes, squeezes it more, then exhausts it longer.
Personally I would source a DJ short engine, change the mains and big ends, fit your heads/new heads and carb it.

[CJH]

Ah, OK, different cam - yes that makes sense. My MV is now with a local engineer to have him free that stuck stud and assess the crank, cam etc. I think I'll wait to see what he says about them. If they're OK I might just build the MV back up 'as is' and enjoy being able to use the cheaper petrol. If the cam is past it then I could look at either a different short engine or perhaps new DJ pistons and a new DJ cam - are the cams available?

Actually, according to that WBX page the valve timing for the MV and DJ seem to be the same. Are the cam profiles different even though the opening and closing times are the same?

[kevtherev]

Ah, OK, different cam - yes that makes sense. My MV is now with a local engineer to have him free that stuck stud and assess the crank, cam etc. I think I'll wait to see what he says about them. If they're OK I might just build the MV back up 'as is' and enjoy being able to use the cheaper petrol. If the cam is past it then I could look at either a different short engine or perhaps new DJ pistons and a new DJ cam - are the cams available?

Actually, according to that WBX page the valve timing for the MV and DJ seem to be the same. Are the cam profiles different even though the opening and closing times are the same?

oops my mistake I thought you were sticking DJ pistons on a DG... hence my post, I shoulda read all of it.
MV cams are the same a DJ
Camshafts are no longer available.

put the DJ pistons on

[CJH]

oops my mistake I thought you were sticking DJ pistons on a DG... hence my post, I shoulda read all of it.
MV cams are the same a DJ
Camshafts are no longer available.

put the DJ pistons on

OK, so it's just the pistons that differ, that's good. I believe the pistons in my MV are OK, so I'm struggling to justify a load of extra expense just for a few HP difference. But on the other hand, the liners are pretty rusty, and they are stuck fast to the heads, and a new set of gudgeon pins might not go amiss, and I'd be replacing the rings anyway, and.....

So maybe a new set of big bore, low compression liners and pistons? What about these? Slightly bigger bore has to be good for torque doesn't it, but would the extra capacity make up for the lower compression ratio?

[dumbo]

to much choice chris any joy from garage i enjoy the read have mate

[CJH]

to much choice chris any joy from garage i enjoy the read have mate

Not expecting anything for a couple of weeks - they're really busy. That's OK, I'm in no rush. I had recommendations for two engine places from two different people, and it turned out they were both recommending the same place.

[CJH]

The only thing you have to do is change the water pump and thermostat housing to fit the oil cooler hose.

Kev

Excuse me quoting you from a different thread, but I thought this question would just clutter up Simon's thread. Do you know if there is a diagram of the way the oil cooler is plumbed into the newer cooling system? Since I'm planning to retain my older cooling system I doubt there'll be a 'standard' solution, but if I know which part of the circuit it connects up to in the new system I can try and do something similar.