Thread: Stiffened v's cross bolted 3.5L block

Terence

I await the experts information on this one, however if you want to make your V8 last longer, make sure that you have some form of upper cylinder lubricant.

It's not possible to add it to the tank like petrol/diesel fueled vehicles but you can add an automatic kit to dispense it as you go. I use a Flash Lube Kit it is only about $85 dollars after postage.

Diana

G`day Terry ,

like Diana , i`ll read the experts view with interest , mine is an opinion with limited knowledge .

Basically the crossbolting is 2 extra smaller bolts that horizontally fit each main cap from opposite sides .

As far as i know the UK defence forces were/are the only ones to have use of crossbolted 3.5s .

In Aust we have the 4.0ltr and 4.6 ltr both factory crossbolts , some of the later 3.9s with B or C etc engine # suffix can be modified to take the bolts but an engineering job and i don`t consider any real need for in general use , if it was asked to peak rev for hrs on end then they would be of benefit .

Both the 4.0 and 4.6 have larger big ends and mains than the 3.5 and 3.9 ( which are the same ) don`t know about the 3.5 crossbolted engine .

Without going into it too far , the stiff blocks start around the yrs you mention though there were modifications in earlier ones to get to the stiff block , ie different places ( valley , front of block between crank and cam , main caps etc ) had more material and or webs etc through the models .

Depending on the scope of the rebuild for your engine if it was maintained through out and running only petrol you could easily expect to add a zero to the 30k and if running straight LPG the figure could be doubled .

Personally i don`t use upper cylinder lube nor do i see i need for it in yours and i don`t discount Dianas suggestion of its use because as i say i don`t use it that`s my preference but don`t say anyone else shouldn`t .

If yours has it`s original heads they should work fine with lpg and also unleaded it`s partly to do with being alloy heads and the material used in both seat and valve which also changed a bit before the time of the stiff block , don`t remember exactly but 79 or 76 rings a bell and also the stem seals it should use or lack of work better with lpg than latter type .

In its life time it will need some work on its head no matter which fuel type .

Making sure it never runs hot ( part of maintainence ) will prolong its life , though not as bigger problem as with the bigger bore engines but they will still break rings . Liner shift in these engines is not the same type of sometimes terminal problem as with the engines of the larger bore .

Cheers

The stiff Block was introduced in 83. Has more webbing and more meat around the cylinders. The early 3.5 and P76 4.4 if worked hard had a habit or cracking along cam bearings.


The 4 Bolt mains is exactly that. A main cap with 4 bolts. When the V8 is pushed hard they have down push on main caps and 2 bolt cant cope. So 4 Bolt became popular in Rovers case X bolt mains are stronger even if still 2 bolt.
I havn't got a pic of a cross Bolt (Opps) but are different and not as strong as 4 bolt. X bolt in 3.5 are rare some one will Know! The 4ltr and 4.6 are X bolted (Disco 2 and P38 RR)
This is not a rover V8 this is a US 4 bolt.


The 3.5 in stock form on gas with a valve saver could last up to 500000 Km even driven hard. They don't have the power to self destruct.
Hope this helps.
Cheers RR.

Originally Posted by PLR

G`day Terry ,

like Diana , i`ll read the experts view with interest , mine is an opinion with limited knowledge . ...

...Personally i don`t use upper cylinder lube nor do i see i need for it in yours and i don`t discount Dianas suggestion of its use because as i say i don`t use it that`s my preference but don`t say anyone else shouldn`t . ...

... Cheers

As Pete suggests upper cylinder lubricant is a personal preference and also they are not usually used in taxis.

My reasoning is that the LPG is a dry gas and with paper filtered air no moisture (humidification) is available to the valve seats at any part of the cycle. This can only add to wear. I have had my Rangie for 23 years at present and would like another 20 if possible so anything that will prolong the engine life at a reasonable cost is a good investment. Therefore I do use a lubricant.

C Ya
Diana

Rangier Rover and Lotz-a-Landies - thanks for your replies on this. Amazing!.

I take it in the picture the webbing of interest has a black felt marker line either side of a crack? or is this a mark to show where the webbing was added?

You have put my mind at rest somewhat - I am really kind of chuffed with the answers here - especially that the LPG seems to extend an engines life. I take it this is due to the cleaner burning, less particulate material washed down into the oil and so forth.

On a different point but perhaps along the same lines, I notice in the UK that they seem to have an interest in the 'top hat' cylinder liner. They say it prevents the block cracking. However I didn't come across this same suggestion here in Australia. Why do you think that is Rangier?

Terry

PLR you mentioned the liners are prone to shifting. I take it there is no way to improve or reduce the chances of this happening?

I appreciated the comments on the heads. I think mine should be ok as they were completely overhauled with new valves, seats done, guides springs etc. I must admit that I have not had an all alloy V8 before so I will be learning a bit. Did these engines suffer from electrolysis at all around the alloy / steel liner interface? If so is there a mandatory treatment for coolant?

You know - I am just so amazed with the amount of information and contributions from everyone ........... and the amount of people who appear not to sleep at night!

Originally Posted by spdterence

Rangier Rover and Lotz-a-Landies - thanks for your replies on this. Amazing!.

I take it in the picture the webbing of interest has a black felt marker line either side of a crack? or is this a mark to show where the webbing was added?

You have put my mind at rest somewhat - I am really kind of chuffed with the answers here - especially that the LPG seems to extend an engines life. I take it this is due to the cleaner burning, less particulate material washed down into the oil and so forth.

On a different point but perhaps along the same lines, I notice in the UK that they seem to have an interest in the 'top hat' cylinder liner. They say it prevents the block cracking. However I didn't come across this same suggestion here in Australia. Why do you think that is Rangier?

Terry

They sure do put T liner's in here in Australia. Mostly the 4.6 are prone to liners failing when over heated. The smaller V8 wern't so prone to liner problems. I have heard of Jag liners being used in some cases.

Pic of a "Top hat"



Cheers RR

5 of the the liners in my 3.9 also failed but the block had also lost its hardness and had to be heat treated twice to get it back to the correct hardness.