b25 with b18 rad?'?? Also engine vibration damper

Post Mon Jan 12, 2015 6:04 pm

Hi goot basically the everything done. Just need to connect the power steering / rad / exhaust and its drivable. Now any chance i could fit my original 318 rad to it? Its the one with a bottle next to it. What rad hoses would i have to use?

did only m40 engines have those dampers?
http://www.ebay.co.uk/itm/BMW-E30-318i- ... 4ae2159089

Post Mon Jan 12, 2015 6:17 pm

ohhh also what electric fans are cheap and easy enough to fit?? anyone had any experience ?

Post Mon Jan 12, 2015 6:28 pm

M40 rad will work with an M20... early e34 520i & 525i(M20) had a similar set-up.

you will need to cut and connect the hose that was previously was connected to the e30 expansion tank. or grab the T-piece hose from an e34.

Just be very careful when you route the water hose that runs under the airbox so it is well away from the alternator fan blades...

those dampers were unique to the M40 engine... must be all that torque they produce

Post Mon Jan 12, 2015 7:05 pm

Afaik, the E34s use the same rad as the M42, not the M40. The M40 rad is 380mm, the E34 (and M42) rads are 440mm.

Post Mon Jan 12, 2015 7:20 pm

so i can use the m40 rad using the m40 rad pipes? thought they were routed differently?

Post Mon Jan 12, 2015 7:29 pm

hmmm... I'm pretty certain we used an M40 rad with M20 top and bottom hoses... even in Oz no probs with overheating. to be confirmed

Post Mon Jan 12, 2015 8:36 pm

Looking at the ETK, in Oz the M40 got the bigger 440mm rad. In the UK it got the 380mm. I'm not sure I'd want to trust a small rad to keep an M20 cool.

MatZZ wrote:so i can use the m40 rad using the m40 rad pipes? thought they were routed differently?

No the hoses probably won't match up.

Post Mon Jan 12, 2015 8:48 pm

if you can wait a week Matt, i'll get some pics up when I get back to show the M20 hose connections and the rad dimensions .
It was all plug and play except for the 3-way heater/t-stat/expansion bottle hose that needed a twist to clear the alternator

Post Mon Jan 12, 2015 8:58 pm

mark_i wrote:if you can wait a week Matt, i'll get some pics up when I get back to show the M20 hose connections and the rad dimensions .
It was all plug and play except for the 3-way heater/t-stat/expansion bottle hose that needed a twist to clear the alternator

It will be plug and play (header tank aside) using the wider 440mm rad from the M42 E30/E34 M20. It won't be with the 380mm M40 rad here in the UK.

Post Tue Jan 13, 2015 9:36 pm

Hmm what can I do or should I do. It would be a temporary rad if I used the m40 one till I can buy a nice shiny good one. So to fit it I need m20 hoses ? Can I use some universal hoses ? Need to work out something a Asap as I wanna insure it and drive it as it's sitting for months now

Post Tue Jan 13, 2015 10:44 pm

You can't fit a 380mm M40 rad to an M20 using M20 rad hoses. The bottom hose will kink and restrict flow and the top rad hose will be too long.
Universal hoses don't always work as the diameter of the stubs on the rad is different from that of the pump housing stubs - universal hoses generally are one size at both ends.

My advice would be to do it right first time with either an E30 M20 rad or an E34 M20/E30 M42 rad. I would not be trusting the smaller 380mm M40 rad to keep an M20 cool - an M20 2.5 head doesn't need a lot of persuasion to cook and crack itself.

I'd get a wanted post up on here for a rad. I'm sure one of the traders on here will have a suitable rad for not very much.