Losing the Viscous Fan - good or bad idea?

[E30BeemerLad]

I am going to be changing the timing belt, and ancillary belts on the bank hoil weekend, well my old man will be, i'll be the chimp making tea and taking abuse when he carves up his knuckles etc

Anyway, as the viscous fan is going to have to come off etc, I was just wondering if it made sense to lose it and fit an electric fan to the front of the rad?

Given that the viscous fan obviously takes drive from the pulleys and belts on the front of the engine, presumably this saps a wee bit of power from the engine, or is it too minimal to make any real difference to performance and fuel economy on a 325.

I saw the idea when looking at a guide on how to to the 3.5 transplant, which needs you to lose the viscous fan because of the location of the dizzy being so near to the rad.

PS - if anyone is interested in a decent guide to the 3.5 conversion, I have full details in a mag called Practical Performance Car, edition 5, but these are prob all sold out now. Edition 1 regularly goes for Ԛ£25+ on ebay and I have every edition so far.

So, getting back to it, worth while doing, or should I just leave as uncle fritz intended?

[Jos]

Reason for the change in the 3.5 conversion is not just to do with space. The amount of cooling provided by the viscous is pathetic at idle and not enough to keep the engine cool when sitting in traffic. Seeing as we are apparently in for a scorching summer I would say change it

[E30BeemerLad]

Thanks Jos!

How much hassle is that 3.5 conversion being? What have u used as your source vehicle? Apparently the sump on the later M30 is better and allows the engine to sit further back, with a couple of whacks to the bulkhead apparently. The engine sitting too far forwards and being heavier than the 2.5 lump is an apparent criticism of some of the early Hartge conversions, car ends up too nose heavy.

I really fancy the idea of doing this at some point in time as all the parts can be robbed from other BMW siblings it would appear, with the exception of needing to get propshafts shortened? Am I right? A late 535 manual or E28 M535 being the preferred donors?

[Jos]

Not really started the conversion yet, just doing lots of cosmetic stuff to the bodyshell 1st, killing rust, resealing and cleaning etc.
The donor I used was an e23 735i auto, apparently there are 3 sumps in existence. The sump I have has the reservoir about 1/3 from the front of the block, I suspect I will need to change it although I am not certain yet. The M30 is a heavy block, 143kg vs 117kg for the M20.
The M535 e34 would probably be the best choice as it will have the correct sump, use the single pulse sensor instead of the speed/position sensors on the earlier engines like mine. Try to get a donor with an LSD, the 7 series actually all come with 3.25:1 LSDs but a 3.64 would be a better choice. The 535i came with either a 3.64 or a 3.45 diff, both these would be excellent choices. Propshafts do need to be shortened, also the location of the centre baring is different, the e30 M3 prop is probably the best way to go but at Ԛ£300 each I don't think I will bother looking at that. Looms look easy enough to do, although time will tell on this one... I couldn't get the engine to run in the donor, fuel ok but no spark, probably a sensor on the crank had failed, they didn't look too hot when I took the autobox off. Don't need to change the fuel pump as the regulator on the injector rail sorts out the fuel pressures and the standard pump can cope fine.

I plan on writing a guide once I am done, I am taking loads of photos, some of them are in the Gallery section but I have a lot lot more than that.

[buster]

i changed my fan ages ago when it jammed on .I ran it for a week without a fan,and it was ok but if it sat still too long it would start to creep up.I fitted a fan off a series 2 rs turbo.Its spot on

[Widge]

I'm gonna do thid before the summe kicks in, makes no sence having crap coolig that is costing BHP even when not in use. What thermostat is every one using? will one of the later BMW ones fit in to the blanking bolt holes on the thermostat housing???
Cheers

[nav786]

have you thought about braking upgrades yet for the 3.5? i'm on the look out for a donor car at the moment. As mine is a 318 what upgrades would you recommend for a 3.5. i take it the 325 brakes will be no good?

[Andy335Touring]

325 brakes are fine for road use for a 335,if you are going to do some track days you will want some thing better.

[E30BeemerLad]

Cheers Buster, nice lookin car too make
Where 'bouts in Teesside are you, i'm from Norton/Billingham

My car used to be up there for a bout 4 years when 2 mates owned it before me.

[shelle-smokeahama]

325 brakes are fine for road use for a 335,if you are going to do some track days you will want some thing better.

AND THE BETTER BRAKES WOULD BE???? NOT THAT LITTLE 280 WILLWOODS KIT??? ANYTHING ELSE???

[Andy335Touring]

I want to keep the original wheels to keep the sleeper look that i like so i'd be stuck with the 280mm kit.

The only wheels i'd change to is Hartges.If i did that i could go bigger but changing the wheels and brakes is to much dosh for me at the mo.

Plenty of kits out there but it depends on your wallet.

[buster]

cheers e30beemerlad,im in guisborough,near middlesbrough.Your car looks like my old car.Is it a 325 ise on a F plate.I won't say reg in case it is.