6cyl SWB?

[steve b]

I'm thinking more of shrink fitted tophat plugs , so a counter bore to the crank face of the FW holes and plugs machined to fit when FW is warm (oven usually) and frozen plugs and whatever diameter machining to suit the crank spigot , I'm sure Vulcan bomber or EJParrott can advise on this for exact technique and class of fit

cheers

Steve b

[Bigj66]

Small update. I have been sent a photo of the 3.0 flywheel from a Rover specialist and it has the correct 8 bolt pattern. I wasn’t sent the diameter so I can compare with the LR version so have asked for measurements.

Seems you can buy them in Sainsbury’s 😳

[secondjeremy]

3 litre had a 10in clutch, the largest LR used was a 9.5.  I don't know if the clutch presser bolt pattern is the same.  9 and 9.5 is save for the positions of the dowels.

I came across this when i fitted a BMC 2.2 litre diesel - which used the BMC 10in presser plate and the Rover 3 litre driven plate.  This fitted into the OHV type bellhousing - I mention that as it looks slightly fuller than at least the early ioe bellhousing.

Some early forward controls may have had the 3 litre engine - the ones for which no parts books are available - but which justify the mention of SU carburettors in the drivers handbook.

[Bigj66]

I’ve just received confirmation that the 3.0 flywheel out of the manual is the same diameter as the auto and thus too big.

Bugger.

[Bigj66]

Well I haven’t given up on this just yet having messaged Jeremy and Michele (thanks guys) read through some interesting posts and done a bit more research.

Whichever way I go I will need to modify one or two parts to get the gearbox and engine mated. Having looked at a number of options, each with their own pros and cons, I think I will try the modified flywheel route as this seems to be the least invasive and will retain a greater number of standard components.

Here is the standard 2.6 flywheel with the 6 bolt crank pattern.

Here is the spacer off the end of the 3.0 crank showing the 8 bolt hole configuration.

If I place the spacer over the flywheel you can see that it would be possible for a good engineering company to weld up the existing holes in the flywheel and redrill them to the 3.0 pattern along with the dowel holes.

If I can get this done then I can fit the 2.6 flywheel to the 3.0 crank and use standard LR parts to complete the process. I’m not a welder but I believe TIG rather than MIG welding would be more appropriate for this? At the same time I can get the face of the flywheel cleaned up with a skim on a lathe.

Can anyone see any issues with this plan?

[Bowie69]

Can't see an issue from here

[FridgeFreezer]

Would there be some trickyness with welding up a cast flywheel? Also potential for it cracking around the bolts due to the effect of the heat, would make me slightly wary of it but I do worry about this sort of thing more than most others.

I'd assume somewhere competent to weld up cast bits would know what they're doing and know if it's going to be safe to use.

[Bowie69]

38 minutes ago, FridgeFreezer said:

I'd assume somewhere competent to weld up cast bits would know what they're doing and know if it's going to be safe to use.

Yeah, that was my assumption, that the bloke you take it to knows what they are doing and how to treat the metal properly before drilling.

[Bigj66]

Valid points chaps. I’ve just quite literally come back from the engineering company who will do the work for me. They do development work for F1 companies so the standards are quite high.

 I need to obtain some accurate dimensions of the crank boss but in essence yes they can do the work for me 😀. That means I should be able to use the standard 6cyl LR bell housing and clutch.

As for the engine mounts needing to be moved forward about 4” on the chassis, could I instead extend the engine block mounts rearward and keep the existing 4 pot chassis mounts?

[FridgeFreezer]

Part of me wonders if getting a new flywheel machined might not be the worst idea, rather than modifying a crusty old one?

[steve b]

Make sure it's set to the same rotational location as the standard one to retain balance , I'd still prefer headed shrink fit plugs to welding , with maybe a machined loose ring about 8mm thick to go between the head of the bolt and the face of the flywheel to spread the torque load of the bolt . 

Good to hear you are going to go ahead

cheers

Steve b   

[Bigj66]

The guy I spoke to did mention the possibility of plugging the holes but I’ll leave it to them as I’m no expert on this subject.

I did think of a new flywheel but I reckon the cost of having one made would be pretty high. It will be around £200 for the mods alone.

The rear of the flywheel will also need to be opened out on the lathe as the boss of the crank (not to be confused with the Cranky Boss), fits into the recess and is centred in that way along with the two dowels.

The bolts themselves just serve to hold the two together rather than act as ‘weight bearing’ in their own right.

Trial fit of the LR flywheel housing and starter on the 3.0 block.

[Bigj66]

This is a link to a 4-cylinder to V8 conversion kit on EBay. Looking at the engine mounting brackets I wondered if I could do the same with the 6 pot rather than move the chassis mounts forward?

https://www.ebay.co.uk/itm/Conversion-kit-to-fit-V8-in-place-of-4-cyl-series-II-or-III-Land-Rover/172941115539?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649

Im assuming they bolt to the existing chassis mounts?

[Gazzar]

The only concern is have about using adaptors to pick up on existing mounts is that the balance of the engine is now nose heavy. This may be totally irrelevant, especially with a gearbox and transfer box bolted to it.

 

[Bigj66]

21 minutes ago, Gazzar said:

The only concern is have about using adaptors to pick up on existing mounts is that the balance of the engine is now nose heavy. This may be totally irrelevant, especially with a gearbox and transfer box bolted to it.

 

That was my concern and I reckon there must be a limit for that very reason. Just not certain what that limit is.

[Gazzar]

If you brake hard, I'd worry it might lunch on the axle.

It should be fine.

I'm going to do exactly this when I'm putting a V8 in my 109 with a R380.

[Bigj66]

Do my eyes deceive me or are the 2.25 petrol and diesel flywheels 8 bolt patterns? Anyone have one in their shed they can check for me please and maybe take some measurements?

[secondjeremy]

What i do know is that the later 5 bearing engines have a different pitch circle to the 3 bearing ones - sorry to be vague but I can't remember which is bigger.

 

The 3 bearing engine seems to have 8 bolts - I think the 5 is the same on a different circle.

[Bigj66]

11 hours ago, secondjeremy said:

What i do know is that the later 5 bearing engines have a different pitch circle to the 3 bearing ones - sorry to be vague but I can't remember which is bigger.

 

The 3 bearing engine seems to have 8 bolts - I think the 5 is the same on a different circle.

Cheers. If someone is able to measure the diameter of a 2.25 flywheel and the PCD of the bolts that would be really helpful.

[Bigj66]

Well here’s a stroke of luck (at last). Seems like the 2.25 diesel flywheel will fit straight onto the crank of the 3.0 engine with no mods  

Question - is there any reason why I couldn’t use a diesel flywheel as opposed to a petrol one, weight, thickness? Presumably I could just fit the S3  clutch assembly as they are all the same according to the manual including the spigot bush.

[secondjeremy]

6 cylinder engines are notorious for suffering from crankshaft vibrations - some are merely annoying, whereas others are rather more spectacular resulting in breakages.  I don't know if the 7 bearing Rover 3 litre engine suffers - and if the original flywheel is part of the design.

there was a nice article by SH Grylls on the RREC site which explained when it arose on Rover 6 cylinder engines and how they dealt with it.

 

The 4 cylinder diesel and petrol LR engines share the same crank dimensions.  petrol have a cast crank, diesels a forging.  Spare diesel cranks were supplied for both engines.  I know they fit as when my S3 diesel engine made noises and eventually stuck solid I found a petrol crank inside.

I think the diesel flywheel is bigger than the petrol one - and the starter is in a different place - so a petrol flywheel may be what you need.

 

 

[Bigj66]

I’ve picked up a diesel flywheel for a couple of quid this morning off EBay so will give it a try when it gets here. The seller emailed me the dimensions and bolt PCD which match those of the 2.6 flywheel and the Rover crank. The petrol and diesel flywheels have a different part number in the manual which may explain the difference in size you mentioned. Worst case is that I need a petrol one.

Looking at the engine mounts again I took some measurements of the position of the chassis mount bolt centre on my 4 pot and those on the rover engine. They are exactly 150mm apart. I’ve marked the position of the 4 cylinder mounting centre with the stick in the photo.

Question is would extending the engine mounts rearwards by 150mm cause any issues like vibration? I’m thinking that an adapter plate made out of 12mm steel with reinforcing ribs could be bolted to the block in place of the existing mount and then the mount either welded to the plate or bolted to it.

[lo-fi]

8 minutes ago, Bigj66 said:

plate made out of 12mm

Nige, is that you??? 

Joking aside, that's probably overkill, but no harm it being beefy. I'd say it's a solid plan, it's basically what I've done at the gearbox end of my conversion, and the engine too somewhat. I didn't want to chop my chassis.

 

[Bigj66]

9 minutes ago, lo-fi said:

Nige, is that you??? 

Joking aside, that's probably overkill, but no harm it being beefy. I'd say it's a solid plan, it's basically what I've done at the gearbox end of my conversion, and the engine too somewhat. I didn't want to chop my chassis.

 

I had some thoughts about drilling and tapping two new holes to take the repositioned mount but I’m not even sure if a thread depth of 12mm would suffice or would it be best to use a nut and bolt?

[lo-fi]

Just build a nicely webbed piece to pick up the existing holes on the block and extend back to the mounts on the chassis. 6mm plate with strengthening webs will do the job. Drilling new holes in the block isn't likely to end well where there isn't extra meat cast in for bosses.

One other thought.... If the oil filter arrangement is the same as the 2.6, will that not foul the left hand mount in that position? 

Also, before you get making anything, are you 100% sure you've got enough room to move it forwards that much without causing a major radiator headache, and you're definitely happy there's room to work on various maintenance chores once it's in?

Fingers crossed for the flywheel by the way.