v8 engine orientation in chassis?

[twodoorgaz]

Over the years I think I've read every thread I can find on V8 conversions - but there's one thing I haven't got my head around and that's the resultant alignment in the chassis (SIIA SWB).

 

Most of the well publicised 'traditional knowledge and tricks' associated with these conversion kits comes from a time before the 38A block castings/serpentine covers as well as the Disco I, II and P38 parts bins contents were commonly available - in my case, while I have a full Milner conversion kit I'll actually be using very little of it. I have an engine with a choice of serpentine covers (interim/dizzy or distributorless -so much more clearance for the front pulleys), a Mocal remote oil filter kit, a choice of sumps and would be mocking up the unit in the old chassis and ordering a new chassis with mounts exactly where I want them - so while its all still very tight, there's a fair bit more flexibility in terms of where the engine is fitted. But I'm convinced I must be missing something obvious that I wanted to run past the forum as I'm aware there are plenty of people who have made use of these later V8 parts to good effect in their Series LRs.

 

I think I'm right in saying that with a factory 2.25, the engine block sits level in relation to the chassis rail (as in it isn't angled nose or tail up) and the crank centre is parallel to the chassis rails but offset a few inches to the Left Hand Side (UK passenger side) with the crank shaft pulley lined up with the tubular hole in the front crossmember for the PTO/starting handle.

 

But whenever I see a V8 conversion, it looks like the crank pulley is typically positioned centrally in the chassis (so if a starting handle were to be used, not that it would, then the crossmember hole would not line up with the pulley dog) - which must mean that with the gearbox mounts left were they are that the engine/mainbox combo runs slightly diagonally across the gap between the chassis rail. I'm also seeing some that seem to be angled tail down (rear main seal lower than the front).

 

Obviously its a LR and the engine position is determined by the installer's choice of mount position, but are there fundamental reasons why a V8 couldn't be fitted in the same orientation/with the same crank position as a 2.25 - so paralell to the chassis rails and offset slightly to the left/passenger side?

 

Any pics would be very helpful - I'll be keeping the gearbox/adaptor plate in the factory location and would really like to keep a traditional (albeit uprated - like this) radiator position rather than fitting a crossflow rad on top of the front crossmember.

 

 

Edited February 22, 2023 by twodoorgaz

[FridgeFreezer]

I thought they were always offset slightly as the gearbox is offset - it could all be an optical illusion.

This is on standard engine mounts in a genuine V8 chassis (before: 3.5 carbed - after: 4.6 EFI) I think there's a bit of parallax at work in the pictures, I'll stand on the front bumper next time!

If you look at the engine compared to the centre line of the vent flaps (left) or the bonnet catch (right) you can see the offset.

Here's a V8 in a Series - 4.6 but 3.5 front end, again you can see the offset:

And later with a proper 4.6 front & top:

 

 

 

[twodoorgaz]

wow - thank you.

 

As you say, it could be that I've been tricked about them being centralised in the engine bay after seeing so many pictures taken from (presumably a small) an angle. I hadn't seen so many pics that clearly show the centreline offset to the left.

 

That could well answer my query comprehensively.

 

The engine I have set aside for this project is a bit of a special one: its one of the 94/95 3.5L/3.500" bore 'service' engines that were based around the 38A block - but without all the finished machining done (like a 3.5L version of a 3.9 'interim' bottom end). I'll be having the machining finished (crossbolting, cam retainer, line bore to 2.5" journals for a 4.0 crank and clearances for counter weights and top hat liners) so it should end up being the strongest possible (factory-ish) variant of the 3.5L BOP/Rover V8 (complete overkill for such a low output engine, but its an engine build that has been on my bucket list for years) - so I should be free to use a P38 front cover with megajolt as well as the more snug 3.5L cast manifolds. I mention this as its really good to see in your photos above how dramatic an effect there is on engine length when using the smaller pump and thin timing cover: really transforms the installation even compared to the old-school efforts where people were tracking down SD1 covers and P6 pumps.

 

Just out of curiosity, in the image above with the blue and red/cream series engine bays, is the engine mounted in the standard location? (ie. factory series bellhousing plus milner-type adaptor plate), or has the gearbox been moved back at all? I'm hoping when I mock this up that I'll be able to squeeze a viscous fan behind the factory radiator with a custom shroud rather than switching to electric.

 

Edited February 22, 2023 by twodoorgaz

[FridgeFreezer]

6 minutes ago, twodoorgaz said:

Just out of curiosity, in the image above with the blue and red/cream series engine bays, is the engine mounted in the standard location? (ie. factory series bellhousing plus milner-type adaptor plate), or has the gearbox been moved back at all?

Very much non-standard, it's on an R380 and set a fair way back;

[Gazzar]

Why no starting handle? My series V8 from the factory has a starting handle and a drive dog.

[twodoorgaz]

gosh - very non standard, looks great though. Thanks again.

[twodoorgaz]

31 minutes ago, Gazzar said:

Why no starting handle? My series V8 from the factory has a starting handle and a drive dog.

I just mean that I never use them in practice. I'd still want the hole to line up, just for neatness.

[Bowie69]

V8 is 40mm offset to the left, or the exhaust hits the chassis with standard 3.9 manifolds and downpipes....

As I found out to my disappointment.

[FridgeFreezer]

55 minutes ago, Bowie69 said:

V8 is 40mm offset to the left, or the exhaust hits the chassis with standard 3.9 manifolds and downpipes....

Also worth noting the P38 manifolds won't clear an external clutch release cylinder... ask me how I know!

[Gazzar]

It's packaging, I think they call it. That's why the 101 manifolds are so expensive.

[Bowie69]

I seem to remember P38 manifolds are very close to fitting a 101, with a tweak they go.

 

 

 

[smallfry]

Long time since I have done this to a series, got to 35 years plus, but using the Milner/Phillips kits and Vee belt 3.5 carb and a couple of 3.5 flapper Efi engines. Serpentine engines and 3.9s not affordable used at this time, as not been out long, and distributorless did not exist.

As far as I can remember, engine was on the level, and offset to LH side, about 2 inches, but do not recall actually measuring. Crank centre bolt more or less centralised in the front crossmember hole. I also seem to think the engine was mounted slightly diagonally as you have said ? 

P6 3.5 exhaust manifolds were the thing to use if you could get them, but then I found the RR 3.5 Efi cast iron twin downpipe manifolds, front pipes, and Y piece would fit. I think the 3.9 Efi manifolds are the same, but downpipes (pre cat) are not.

Had to cut the nose off the water pump, so obviously no fan, but tack welded the pulley flange, just to be safe. This left about 3/4 inch between that, and the series radiator, which always coped with the 3.5 no problem. Never had the engine move forward enough to hit the rad, but always welded a "stop" on one of the gearbox mountings, just in case. Electric BMW fan in front of the rad, with sensor in thermostat housing.

Distributorless front end would be far better, and a no brainer really. You might even be able to keep the engine driven fan, but I am only guessing.

Remote oil filter, as this was less expensive than the Milner conversion.

LH footwell had to be modified, still have a template for this, somewhere.

As far as I can remember, everything else is just connections as you would expect.

Only problems I can remember is that the cabin heat in the summer, and snapping rear halfshafts. Always more economical than 2 1/4 petrol, Efi more so.

[elbekko]

15 hours ago, Bowie69 said:

I seem to remember P38 manifolds are very close to fitting a 101, with a tweak they go.

 

 

 

You'll also be hard pressed to find any that aren't full of holes.

[Bowie69]

True, but they can be welded up if necessary, not being cast

 

[FridgeFreezer]

D2 cast manifolds look pretty good too, and their downpipe arrangement (into one large squished pipe) feels less cluttered than the 4:2:1 arrangement.

[Daan]

It very much depends on where the engine is in relation to the front axle; The picture Fridge shows has the engine backward a long way. In an SWB with an LT77 you probably have to move it forward and that moves it closer to the diff, so the offset is needed to miss it at full compression of the axle. There is also the exhaust to consider on both sides and the oil filter location, steering and bulkhead mods that determine the best place. The starter handle working is nice to have but if you have the aforementioned problems considered, this is probably secundary; you could always modify the cross member and bumper to keep this facility. 

Lots to consider and lots of work...

Daab

[elbekko]

3 hours ago, Bowie69 said:

True, but they can be welded up if necessary, not being cast

 

Yes, I've done it a few times. There are some *very* hard to reach spots. Last time I just had to fill in all of the valleys where the pipes come together, and I couldn't get in deep enough to actually weld up the holes 😕

[twodoorgaz]

That's really helpful, thank you everyone.

 

Hi Daan - the position of the engine will be the traditional V8 conversion position (that is that the front of the bellhousing will sit in the same position as it would have in the 4-cyl from the factory. Granted I'm fitting a stumpy R380, but I've already planned on moving the transfer case backwards by 102mm to compensate), so I wouldn't have the same benefits that Fridge has had in moving the engine significantly further back.

 

I've been planning this job for years and years so have had a long time to gather parts - I'll share the list below if its of interest: many years of too much wine and an eBay account has resulted in boxes and boxes of parts stilling awaiting the start of the build. The vehicle I have earmarked for this (lights in wings '69 SIIA SWB) is already flat packed and will be getting a new chassis and bulkhead, so its more of a V8 build rather than a conversion of an in-tact vehicle.

 

The spec is going to be:

• Alisport S2A/V8-specific radiator (not bought)
• crossbolted 3.5V8 with distributorless P38 front cover - mounted in the 'traditional v8 conversion' position. This will be (all being well, thanks to the advice in this thread) mounted parallel to the chassis rails, offset as per 2.25 with the crank pulley centralised in the PTO hole (engine bought but not the cover)
• Sump - unknown, there's a few designs to play with - I plan on sitting the V8 and the original 2.25 on a bench with the fans aligned and picking a sump (P38/Disco II) that gives similar clearance but still works with the P38 front cover.
• Milner adaptor plate (bought)
• Mocal remote oil filter
• 9.5" clutch
• Stumpy suffix L defender R380 with 050A ratio layshaft (both bought)
• Ashcroft R380-Series transfer box adaptor (bought)
• Transfer box moved 102mm backwards on a second bolt-up gearbox mount (brackets will be added when ordering the chassis, which has not been bought yet - the original position crossmember will remain and still clears the box)
• Cut and shut gearshift remote (I have two and can weld and machine cast aluminium) to move the gearshift forward into the factory position
• New transfer box lever pivot bracket bolted to the back of the R380 bellhousing studs
• Shortened rear propshaft - but still longer than 80" specs (have but not modified)
• Extended front propshaft based off a solid 3.9 RR prop - it clears the gearbox crossmember without scalloping (bought but not modified)
• Ashcroft 4-pin or ATB 4.75 rear diff with 24-spline side gears (not bought)
• Ashcroft 24 spline rear halfshafts (not bought)
• Standard front diff (have)
• 10/24 spline front shafts (bought) - I've had some advice from the forum on CV conversions which I may do one day, but for now I'll stick with the UJs
• Heystee disc brake front swivels and Heystee 8" servo on a SIII servo pedal box (all bought)
• 200TDI Defender Disc/Drum/Valve/Master Cylinder setup (bought)
• Reinforced front axle casing (factory, have one and doesn't add anything but its a nice feature)
• 6.5J Defender 130 rims (bought)
• Reshaped bulkhead (will be new from Rob Owen)

 

Now that, thanks to yourselves, I know that the engine can be fitted straight and level, the only bits I have left to figure out are:

• The absolute best exhaust manifolds to use - I'd like these to be cast due to the look I'm going for (being a 3.5 I have access to the whole LDV, MGB, Rover and Land Rover parts bins without worrying about strangling a larger engine)
• Whether I can keep the engine driven fan. I really want to - provided I can squeeze it behind the factory-sized Alisport radiator. I think it will fit well, but I'll need to pick the slimmest factory fan I can, so will measure up all the viscous and fixed fans I can find. I suspect a fixed steel fan on a custom boss attached to the serpentine water pump would sit tightest to the engine. I would also make a shroud and cowl to cover this - I'm hoping that a custom steel one that mirrors the factory design will look ace.

 

Geeky, and has cost a hell of a lot over the years - but I think the setup (cooling, transmission strength and braking) would be very well matched to a standard 130bhp/185lbft V8 without having any obvious weak points. The aim is to finish the traditional V8 conversion by just changing the bear minimum of parts needed to take it up to 'production-ready' strength/reliability without any engineering compromises (rather than aiming for uprated off-road spec). The gearing took a long time to work out, but the 5-speed setup I have should give final ratios that are pretty much identical to a Series 1st-4th + OD 4th.

 

 

 

 

Edited February 23, 2023 by twodoorgaz

[Bowie69]

3.9 cast manifolds are very well thought of, in fact I think John Eales used to sell ported versions of them, as well as then developing their own larger bore cast version for sale later on.

I hand ported my own to suit, and removed quite a bit of material.

[twodoorgaz]

lovely, thank you. I'll keep an eye open for a pair once I try the engine in the chassis.

[FridgeFreezer]

1 hour ago, twodoorgaz said:

Alisport S2A/V8-specific radiator (not bought)

I'd save a ton of cash and look for something stock or universal that will fit, Allisport stuff is lovely but you don't get change from £500 these days and that's just madness when you can get a variety of shapes & sizes in aluminium from eBay for £100 delivered.

[twodoorgaz]

I'll have a look into it. Even bypassing the universal ones, it does seem that custom ones from similar companies are coming in at about half the price.

 

I might take a leaf out of the Retropower book and make one out of cardboard and toilet roll tubes complete with flanges so I can physically bolt it in to trial it before sending it off to be made in aluminium. It would be nice to have the upper surface bead rolled to match the pressings in the original brass item, if I find a friendly manufacturer then I could do the rolls or pressings in some blanks and supply them to be included.

Edited February 23, 2023 by twodoorgaz

[FridgeFreezer]

In addition, I'd make it out of copper given the choice.

[smallfry]

I also would not bother with an Alisport rad. Series 3 one will be fine for your spec.

I see you state a 4.75 diff. I think you will find this too low, unless you want to a lot of serious off road work.

I used standard 3.54 diffs, even with a Fairey overdrive, and always found these to be fine, even for towing large trailers, so you might want to try it out first before spendy spending.

You will not have any problem with sump clearance. If going for distributorless front cover, you will also need the matching oil pickup pipe.

[Bigj66]

My Thor V8 sits nose up by 6 degrees if memory serves and slightly offset whilst being as far forward as possible to allow the fitting of the ZF auto.

The gearbox will dictate the engine position as that needs to be in the correct place for the rest of the drive train and things like gear levers etc.

I used EFi manifolds and a stumpy oil filter to clear the axle along with a TDi aluminium radiator.