850r engine

[mickmang]

Hi just brought a 850r with a blown motor , head is ok, bottom end has blown out , no 2 and 3 pistons .I can geta s70 t5 bottom end which is in good nick and was wondering if this is the same motor ,will it fit with my cylinder head . S70 is a 97 my car is a 96 850 . Thanks in advance Mick

[Tomcat]

Yep,should fit ok. There where no major changes to the engines until much later on (after 99-2000).

[t5lover]

hello mate i dont think there is anyproblem with doing tht mate there the same engine good luck,,,

[AlanG]

As has been said buddy. Your car was fitted with the same engine as the 850,so can't foresee any problems.:funkybana

[mickmang]

Just picked up the new / second hand bottom end .Looks good thatch marks in bores etc . My only question is the stamp on the block says t3 not t5 . was wondering if theres any difference , as i intend on using this bottom end with the cylinder head from the original engine . Thanks Again Mick

[Alan M]

You shouldn't find any problems with mating the head from your 850 to the 70 bottom end. While the bottom end is out why not drop the sump off and split the rods to check the bearings are in good order? It will save time and hassle once the car is assembled. The T3 and T5 refer to model types dependant on what car the engine came from.

[nobananas]

I'm running an S70 block with S70 pistons but 850 rods (S70 ones were banana shaped !) with my 850 head on it !. Had no problems at all. I'm also running a C70 gearbox with the concentric slave.

[Rob_ioClean]

Could be worth using aftermarket rods on it? I think they are the main weak point of the T5.

[nobananas]

The rods should be fine up to around 350 BHP, certainly have been fine on mine running Rica 304. Did contemplate fitting them to my engine when I rebuilt it but the cost of the rebuild parts alone (bearings, piston rings etc) came to around a grand and I couldn't justify spending almost the same again on a set of rods (not for what it gets used for anyway ie commuting)

[Filterlab]

The post '96 engines had the stronger con rods so it'll be a bit sturdier.

[mickmang]

Thanks guys , another question . Got the head back from the engineer , recut valves ,new valve guides ,preesure test , crack test, head was warped . He also mentioned that to deck the head ,level it ,he had to take off 20 thou of the block , this seems excessive to me . Does this sound right to you guys . Thanks Mick

[Alan M]

If the head was warped majorly he would have had to take off a considerable amount off the head so skimming the deck of the block also would be a little to much IMO but it may have been extremely warped too. The deck faces I have seen stripped have all been okay to use with only the head needing a skim.

[Jod T5]

The post '96 engines had the stronger con rods so it'll be a bit sturdier.

Really?..
There is conflicting statements that the R had stronger rods but this has never been proved as far as i can tell..
Its not the bhp that kills rods it is the torque....
Jod