Help with my 3.5 rebuild

[Big Gee]

Hi Guys, I'm a complete newbie to this so please forgive me if i ask stupid questions......or should i say when i ask stupid questions lol

Amazingly enough i managed to convince my wife to let me do a reuild in the spare room assuring her that it's no big deal (I'm going to pay big time for that little lie soon enough)

I got my hands on an E reg 3.5 range rover v8 engine, engine no 25d10928b.(cant really find info on this no, but not sure where to look)

As i say I'm a newbie at this but something i always wanted to do so asked a mechanic friend to come have a look and give me some advice, I'm only going for a basic rebuild with original parts to begin with.

The only thing he mentioned which really concerned me was something about hardened valves in the head which means the engine might not be able to run on unleaded petrol without some major machine work being done on the valves, seats etc.

If anyone could shed some light on this it would be much appreciated.

Cheers

Gee

[woodytz]

No problem there,the rover v8 is bomb proof in that department.

It will also run quite happily on LPG with no modification

cheers woody

[kingdong2]

Hi and welcome to the forum

as far as i know all rover v8 engines from the 70s will have hardened valve seats in from new but may need recutting ?

graham.

[Quagmire]

Gee,

I recently rebuilt a 3.5 to go in my 90. Had never done a v8 before, but with the help of people on here and the v8forum i got there. Check it out here:

My rebuild

As for the question of heads, you should be fine your engine number prefix of 25D gives the unit as being

"25D00001A R.R efi Auto 9.35:1 cr 1986 onwards" -(Courtesy of V8forum)

The only heads that are no good for unleaded are the ones used on the Rover saloon cars such as the P6. These are easily identifiable as they have smaller valves and "short reach" spark plugs.

Have fun!

[FridgeFreezer]

For the money and effort I'd have to ask if it's worth rebuilding a 3.5 lump these days - a good running 3.5 EFI won't set you back more than £250, maybe £300 if it's still bolted into a rusty Range Rover.

I've not heard about any of the V8's having trouble with unleaded, just stick it in and make sure the timing's right.

[Quagmire]

Having just seen Fridge's post i should add that i did try to find someone who had killed P6 style heads on unleaded (as my first block was a P6 one), and nobody had...

[FridgeFreezer]

This could be inaccurate but isn't it the case that aluminium heads need hard inserts anyway as you can't have a valve seating against soft aluminium? Most of the older vehicles designed for 4-star had iron/steel heads which could get away without any seats until unleaded came along.

[Big Gee]

Hi Guys,

Thanks very much for the info regarding this matter it has lifted a bit of a weight off, I know i could probably pick up a half decent 3.5 cheap enough and drop it into something and go but been wanting to do this for so long that i'd only cheat myself out of the fun in doing it(winding up the wife is just a bonus lol).

And if all goes well then i'll start looking into upgrading cams etc for round 2.

I've been reading throught the forums and tech archives for a while now but was wondering if there are any obvious rookie mistakes to beware of, I'm waiting on couple of books coming before i begin rebuilding.

Cheers

Gee

[Hybrid_From_Hell]

I'm only going for a basic rebuild with original parts to begin with.

Er whats that then ?

Rebuilding a V8 is NOT cheap if you use decent parts and do it right

1st Off why exactly are you "rebuilding it" whats wrong with it ?

and that may then lead you to maybe going 3.9 vs 3.5 going HW vs Flapper

(which is a huge improvement) and the newer engine may cost less than the

key parts in a 3.5 rebuild.

Also bear in mind the costs of a rebuild are pretty much the same for a 3.5 / 3.9 / 4.0 / 4.2 / 4.6

the only think that varies is the value / price paid for the unit being rebuilt - whilst you

can say you 3.5 is £0 in the aquistion costs you'll be amazed what you can pick up a turnkey complete 3.9 for

Nige

[FridgeFreezer]

If you may upgrade the cam in the future there seems little point doing a rebuild - a cam kit can include new lifters & pushrods, gaskets, upgraded timing gear & duplex chain and you'll have to have almost as much apart to do the cam as doing a rebuild in the first place. Since it's not worth spending big money on tuning for the Rover V8 you may as well buy a reasonable cam kit (f'rexample Real Steel Stump Puller) as it'll work out almost the same as just putting stock bits in.

Then again, for the money that'll cost you could just buy a nice 3.9 lump and have more torque to start with

[Quagmire]

Rebuilding a V8 is NOT cheap if you use decent parts and do it right

I have to agree here, I did mine over a period of many months, and still haven't added up everything i spent (And don't want to ) I rebuilt my engine because i wanted to- it was mostly fun, and also because it was important to me to have reliability. By rebuilding it this has hopefully been ensured. I also now know every part of my engine inside out, which should help with any fault finding i may have to do.

If the engine runs OK and doesnt look too black under the rocker covers i would just take the inlet manifold off and valley gasket, check the cam for wear and go from there. If it is full of black cornflakes and smells horrible then more work may be required and it might be cheaper to do something else.

But whatever you do, and this is very important- don't go Diesel!!!

[Big Gee]

Cheers for the tip fridge freezer, I wasn't aware that i could get an upgraded cam and accessories for around the same price as stock items, looks like i'm going for a new cam after all .

When I removed the rocker covers they were full of black flakes but would've done a full rebuild regardless of condition anyway which might sound crazy but like fridge this is something i've wanted to do for as long as i remember, and learning what everything is and how it all works together is more important to me than having a ready to run engine.

As i said I'm a complete newbie to this, and although i have a bit of mechanical experience none of it involved the internals of engines.

Now for what i imagine is the 1st of my many stupid questions to be asked

1 Is it easier to set the engine up on carbs than efi and would there be much benefit in doing so?

Again thanks very much to everyone for all the tips and help so far

Gee

[nick w]

my f reg is fine on unleaded all about the octane to timming ratio i belive

[Guest noggy]

EFI is a lot better, more horsepower... easier to set up, can be mega squirted etc.

carbs.... very temprimental on extreme slopes they can starve the engine of fuel, but the look and sound coool!!

[Quagmire]

OOops, when i said this:

The only heads that are no good for unleaded are the ones used on the Rover saloon cars such as the P6.

I should have actually said "The only heads that are no good for unleaded are the ones used on the OLDER Rover saloon cars such as the P6."

SD1 bits are fine and have the larger valves too. The Vitesse actually had waisted/wasted stems on the valves to give better breathing too, although these then became standard fare on all RV8 heads a few years afterwards.

As for carbs vs EFI, i am running SU's but have bought some EFI stuff and am just waiting for my wallet to recover from Christmas before i get the rest of the stuff and fit it along with Megasquirt and EDIS. The Carbs have done well so far, and i am lead to believe that Carbs give a nicer V8 noise when compared to an EFI motor.

However i would like to improve economy and get (near) perfect running if i can so hence the move to EFI...

[RPR]

It seems that twin SU's are the best way to go from a carb perspective. My Edlebrock 500 cfm, was far from ideal and would readily flood on steep climbs causing nasty stalls. Not much better on descents. The sound, however, especially of the secondaries opening, was quite impressive!

[FridgeFreezer]

I'd agree that SU's are the least evil of the evil that is carbs - my Holley 390 was terrible in every way, the Weber/Edelbrock 500 was quicker but hated off-roading and used more fuel than a supertanker. Bolting a bone stock flapper EFi setup on was significantly more powerful than £500 worth of carb & inlet manifold, and MS&EDIS is another leap over that.