Raise V8 CR

[Rikkk]

Hi, I got a stage 1 3.5L V8 in my County, its the weak army motor with 8:13:1 CR

It has terrible bad power due to all de-tuning the army did and truck is a overland camper and weighs in on 2500kg

So at the moment I am doing 60 up some hills... :(

I have removed the air-intake suppressors and put a MSD double ignition in with higher power cables and plugs

On the flat its fine being able to cruise on 120 with just the LT95 four speed gearbox, but as soon its uphill I am screwed with Maxies 35" rubbers

So I am trying to give it a bit more torque

Does anybody know if the torque is lowered in these engines to 8:13:1 from the 9:35:1 the original 3.5 V8 had by the heads?

Can it be restored to this by changing the heads to heads from a 9:35:1 engine?

Any help appreciated

Cheers /Rik.

[Hybrid_From_Hell]

The compression is in the pistons not the heads. Changing heads for late ones won;'t really make any noticable difference.

NHP & Torque on the 8.13 was way down on a 9.35 / 10.5:1 engines.

If it has the pulsair system as well bin that will help a bit, but, to be honest swap block for a 3.9 unit is the route to look at ..

 

Nige

[Bowie69]

You can gain a *bit* with a skim off the heads, but unlikely to make a huge difference, there is a minimum thickness for the heads, plus, take too much off and you have to skim the inlet manifold as well! Short answer - do it with pistons if you really want to.

You can change pistons relatively easily without removing the engine, but eight pistons will cos you a bit. Obviously you need to give the cylinders a light hone for the new rings. If you have the cash and don't mind pulling the lump out, get it done by a machine shop and all good.

You can put a 3.9 cam in with new followers for more grunt again, and is relatively cheap.

 

The 8.13 CR engines were about 125bhp without the inlet restrictors, 'normal' 3.5s on carbs were 135bhp, injected 3.5s were 155bhp, which is a marked improvement.

Then came the 3.9, with ~185bhp and injection, lovely engine, and a real upgrade over a 3.5. If you aren't tethered to the 3.5, then a 3.9 or even 4.6 is the way to go.

having said all this, what transfer box ratio are you running with 35s? To get somewhere near stock, you need the very low 1.667:1 version ideally. It may be that swapping this out would be more beneficial than tweaking the engine to burn more fuel....

[Eightpot]

Take the inlet manifold off and look at the state of the cam - they don't last long but will carry on chugging along with masses of wear on the lobes.  Timing chains are prone to stretching as well. 

A well sorted low compression v8 still has plenty of grunt. 

[FridgeFreezer]

You can spend money to improve your 3.5 but IMHO the best value option is drop a 3.9, 4.0, 4.2 or 4.6 in - it will bolt in, although you'll need to sort the fuelling & ignition side depending on which way you go - a lot of folks round here using Megasquirt EFi (from Nige) with distributorless ignition which is an improvement over carbs & points in itself.

As others have said, the low-compression 3.5 is a bit limited - you can increase the CR a little, you could fit EFI, you could fit a better cam... although with 35" tyres you might look at lower gearing as well.

[Tanuki]

Agree on what's been said about the cam: I've seen a V8 which had half the valves with only about 0.2 inch lift, which made it totally gutless even though it ran beautifully smoothly!

Also worth checking is the centrifugal advance/retard on the distributor: Engine heat hardens the grease over the decades and can be sufficient to glue the mechanism in the retarded position which will make the engine feel very 'numb' over about 2500RPM.

[110 V8]

Hi Rikk,

as others have said, put a 3.9 in it. For what you would spend on the 3.5 its a no brainer although technically here in NZ you will need to get a cert for the increase in capacity.

Whereabouts in NZ are you?

Andy

[FridgeFreezer]

8 hours ago, 110 V8 said:

as others have said, put a 3.9 in it

I'd suggest putting the biggest one you can find in, there's no substitute for cubes and there'll be very little difference in fuel consumption - my 4.6 swaps have gotten better MPG than the smaller V8's they replaced.

Also the later 4.0 & 4.6 have numerous improvements like being cross-bolted and having a better oil pump, composite head gaskets.

[Rikkk]

Hi all, thank you so much for your replies and yes... all of you are right

I should have put a 3.9 in when I had the chance :(

Thing is, I got this newly rebuilt 3.5 engine for 600 NZD and mechanic cost for the work was $2000; that I thought was a 9:35 CR but after looking into it I realised my misstake, but by then it was already in my bay, so I am stuck with it, I cant justify another 2 grand to pop a 3.9 in even if I find a good one for a good price and wify would shoot me.... a lot...

Also I forgot to tell, I have a 3 inch system on with the double barrelled cast metal extractors from a 3.9, so it sounds totally mental, if it went half as good it sounds I would be very happy puppy

Any no, the increase of exhaust size did not lower the power, rather otherway around actually to contradict what lots of people say, maybe in combination of the MSD box? Dunno?

Ok Hybrid from Hell, I learnt from you today that the change in compression is in the cylinders, did not know that, and there is no Pulsair system (what does that do anyway?) I believe that the guy who did the rebuild was a full purist and put new identical components in

Wont skim the heads Bowie96, way to costly

And Eightpot, engine is only year old since rebuild

Yeah Fridgefreezer, that is most likely my only option; EFI and gruntier cam

Tanuki, it revs fine and changing the timing dont seem to do much difference

110 V8 I am in Auckland

But Fridgefreezer, I have stopped to believe in the saying: there is no replacement for displacement, because it is and its called engineering :)

 

I got the Strömberg carbs on, but I also have a EFI from a 3.9 (not the flapper system) in a box with good injectors

So what difference do you gurus think I should expect by popping in a high torque cam and the EFI (not going mega squirt as I am trying to -save- petrol...)

I am quite capable but think I might struggle to fit the EFI... I could do the cam myself but as that should be done at the same time as the EFI I need a mechanic to help me out, I do it all myself usually but thinking about going to Israel at Central Motoring on Pollen st in Grey Lynn as I use to live in that area and have spoken to him several times and he seems like a good bloke and also do all the work for the Trekker Adventures Landrovers (rented one for a mate over Xmas that I had to repair in Warkworth :D

Again, thank you soooo much for your replies, its been very good learning for me, all replies are worth a lot to me

One other thing I can tell you is what I did with my former engine (same 8:13 CR) was a Pertronix Ignitor3 kit and that ignition made the V8 rev like a rotary engine, truck just took of like a madman from 70 in 3 gear and I could pull it up to almost 90 before chuckin in 4th and my last gear, it was craaaaazy, but in the end I think thats whats killed it and it bent a tapper and suddenly I had oil coming out of my dipstick due to pressure escaping into the sump... but it was fun as long it lasted :D

But this is why I changed engine in the first place :)

Cheers guys

[Bowie69]

The EFI is a very easy swap, you can hope to gain maybe 20HP, which may be all you need when combined with a cam swap.

 

 

[FridgeFreezer]

6 hours ago, Rikkk said:

So what difference do you gurus think I should expect by popping in a high torque cam and the EFI (not going mega squirt as I am trying to -save- petrol...)

I am quite capable but think I might struggle to fit the EFI..

#1 - You tune Megasquirt to suit your engine, if you do it right you should SAVE petrol and have a very driveable machine operating at its best. Hell, you can run switchable maps and have one map for economy and one for power if you can be bothered... although a good map should have economy in the economical parts and power in the power parts as an example, my 127 Ambulance has a squirted 4.6 and averaged 16mpg over the alps on the last holiday - and that's a 3-ton windbreak which cruises at 120kph.

#2 - Fitting the EFI is easier than doing the cam IMHO - you bolt the inlet manifold on, plumb it up (coolant & fuel), drop a high-pressure fuel pump in and connect some wires to the ECU... it's all straightforward as long as you're neat and methodical anyone can do it. It's been written up here many many times.

[Quagmire]

I run megasquirt on my 3.5 (9.35:1 cr) powered 90, and get 21-22mpg consistently. The joy of EFI is that you can have both power and economy. How much of the latter you get is down to your right foot...

[garrycol]

Megasquirt might be OK in the UK where you have support but not in places like Australia or NZ - it might work well but is difficult to set up, the documentation is not very good and the website is not helpful.

Go with a 3.9 injection system and use a 14CUX ECU on whatever engine you choose.

Garry

 

 

Edited September 5, 2019 by garrycol

[V8 Freak]

Or just buy a complete Plug and Play system (Including loom) from Megasquirt V8 .....

Highly likely it can be installed in a day !!!

[Rikkk]

Hi again, hope you guys having a nice weekend

Wonder why non of you have mentioned Holly carb? Like this kit  http://www.thewedgeshopstore.com/tws-four-barrel-conversion-kit-rover-v8/

I also know there are several new "carburettor looking" EFI systems on the market, now I cant find one for Rover engines, but they look like this https://fitechefi.com/products/30021/ 

Then there are these guys as well https://www.classicfuelinjection.co.uk/shop/product_info.php?cPath=114_134&products_id=411&osCsid=9cvfc5h75pucsteksnbe5slt14 But to think my slug of an engine will produce 220 ponies is nothing but ridiculous...

Bowie69, I am not too sure about easy install, one mechanic I spoke to wanted about $3000 to install it... and I have heard its pretty hard from "home mechanics" too, dont I have to tap into the coolant system for the intake as well? Then things gets bit over my head   And horse power sells engines, torque wins races is a saying my team used when I was still racing over in Europe, but I guess 20hp will gain torque as well

Fridgefreezer, that sounds pretty amazing, mine is rather the opposite, like 14 gallons per mile...

Quagmire, that sounds more like you driving a Prius to me...

garrycol, yeah thats what I got in a box, I think thats what I will do in combination with a high torque cam

V8 Freak, but those kits are expensive and then shipping and import tax its more then to drop a 3.9 in...

 

So yeah, when I or rather if I find a mechanic willing to do both conversions for a decent price enough , a new cam and EFI with the 14CUX ecu and hope I get it up enough to climb hills in a normal fashion, been thinking about losing some weight too, but point being to be a real overlander, truck is always ready to go with food, fresh water, full pullout outdoor kitchen, double bed, 270 degree foxwing awning, outdoor furniture, TV, fridge and freezer, outdoor LED camping strip lights, 225 amp hour batteries, fully mounted roof solar panels, so if I feel like going camping on way home from work, I just go, wont need to go home and pack or anything, just need some beers

Cheers guys, will keep  you posted on upgrades

/Rik. 

[Bowie69]

21 hours ago, Rikkk said:

Bowie69, I am not too sure about easy install, one mechanic I spoke to wanted about $3000 to install it... and I have heard its pretty hard from "home mechanics" too, dont I have to tap into the coolant system for the intake as well? Then things gets bit over my head  

Find a different mechanic!

it is 3 wires to get it running once all in, and you can ignore the plenum heater hoses.

[FridgeFreezer]

On 9/7/2019 at 12:01 AM, Rikkk said:

Wonder why non of you have mentioned Holly carb? Like this kit  http://www.thewedgeshopstore.com/tws-four-barrel-conversion-kit-rover-v8/

I had one, it was f**ing awful, flapper EFi was miles better... and flapper EFi is quite shonky itself.

Why would you bother with that "Classic EFI" kit when you can bolt the complete inlet manifold from a Disco/RR on and call it done - and have port injection and 100% standard LR parts.Or just drop a complete EFI lump in like wot I did.

Also, you may be able to compensate for lack of displacement with engineering, but if you apply the same engineering to bigger displacement to start with...

The whole EFI conversion / megasquirt fitting etc. has been written up here many times if you want to know what's involved - as with all work, if you are methodical & take your time it's not hard, it just looks scary with all the wires... well, wires seem to scare LR owners for some reason

[FridgeFreezer]

On 9/5/2019 at 1:14 AM, garrycol said:

Megasquirt might be OK in the UK where you have support but not in places like Australia or NZ - it might work well but is difficult to set up, the documentation is not very good and the website is not helpful.

To be fair, you went MS3 which is complicated and overkill for a Rover V8 - sticking with the simpler MS1 as most of us here have makes life easier, simpler, and means you can get support here.

[garrycol]

Not for a Thor system it is not. 

[FridgeFreezer]

2 hours ago, garrycol said:

Not for a Thor system it is not. 

What isn't?

Thor is not rocket surgery, it's the old system with a thin coat of looking at by BMW.

[Bowie69]

Stepper motor? Make up a bos and use a single wire version.

Pickup? That works with ms1.

[Rikkk]

Hhmmmm, mite be able to come across a Leyland P76 4.4L Rover engine

Anybody got any knowledge about these?

Cheers

/Rik.