m20b25 cracked head

[brian_s]

Right this is just a rant, just noticed that my head is cracked, using coolant, mayo under the rocker cover.

Now what's the options!?

Second hand head/engine - Could still land with a lemon and be in the same position!

Amc head, problem solved I guess but are the heads any good? They flow the same etc? Also pricey.

Engine conversion - A m52 does really tempt me but unless someone is selling a full plug and play type set up I don't think I'd go down that route.

Or just set fire to it! That option seems pretty good right now!

Rambling over haha!

[satan16v]

There's a plug n play 24v for sale in the classifieds

[brian_s]

Yeah just noticed that, will fire him a pm, ideal situation I guess would be to see something like that running though instead of buying blind!

[Blitz]

Is your car a 325i?

[brian_s]

Is your car a 325i?

Unfortunately not, just a m20b25 converted 2dr 320i, it's a good solid shell though

[B7]

Brian you have a PM.

[brian_s]

Brian you have a PM.

Replied

[brian_s]

Anyone out there with a proven good 325 head?

[HairyScreech]

The AMC heads are not as good as the BMW ones from a casting quality and dimensional accuracy POV, However they are within spec.

The ports are not as good in stock form and don't flow as well, however they are a touch smaller and the casting is thicker, this means they are a much better start for a ported head and have been shown to be easier to get gains over the stock 885 from and can outperform a ported 885 (without welding to move the ports about).

I am told these heads are also thicker in the critical cam valley as well which helps.

Trouble is to use an AMC head and have it tweaked to be better your in for £1200 at least assuming you do the build up yourself.

[brian_s]

The AMC heads are not as good as the BMW ones from a casting quality and dimensional accuracy POV, However they are within spec.

The ports are not as good in stock form and don't flow as well, however they are a touch smaller and the casting is thicker, this means they are a much better start for a ported head and have been shown to be easier to get gains over the stock 885 from and can outperform a ported 885 (without welding to move the ports about).

I am told these heads are also thicker in the critical cam valley as well which helps.

Trouble is to use an AMC head and have it tweaked to be better your in for £1200 at least assuming you do the build up yourself.

Cool cheers for the info, would be a good option for a serious big build I bet!

Are tested 325 heads now a rare thing? I think if I do find one now I'm going to keep it tucked away

[HairyScreech]

Kind of, but only because everyone is keeping them tucked away.

[brian_s]

Haha no wonder I can't get one

[ross_jsy]

Kind of, but only because everyone is keeping them tucked away.

I'm not the only one then

[HairyScreech]

Kind of, but only because everyone is keeping them tucked away.

I'm not the only one then

Nope, I'm guilty as well.

[reggid]

I've got a couple 885 stashed away, plus a heavily worked AMC and the head i use on my DD.......

i cut up a 731 head the other day because it was cracked, they don't look any stronger than the 885 in the cam valley not sure about AMC. there is evidence the number 5 was running hotter than others and aluminium doesnt like heat the mechanical properties go to shit.

i must say the design is hopeless there is no support for the cam journals other than 5-6mm of cast alloy like a half pipe tube no gussets. i understand they dont want to restrict the flow of coolant but it wouldn't take much to improve it at the design stage without affecting coolant flow to any significant degreee

[brian_s]

Cool I'm glad you've all got one stashed away

[brian_s]

Think a m52 is the way forward now,

[Brianmoooore]

There's this on ebay: http://www.ebay.co.uk/itm/BMW-325i-525i ... xyl5lSKGTg
Looks like the seller doesn't know what he has - the description is all for an M50, which doesn't match the pics.

[brian_s]

There's this on ebay: http://www.ebay.co.uk/itm/BMW-325i-525i ... xyl5lSKGTg
Looks like the seller doesn't know what he has - the description is all for an M50, which doesn't match the pics.

Just had a look, to say his feedback is poor is an understatement

Thanks for the help though

[Brianmoooore]

A lot of the bad feedback is because he sent the wrong part - he doesn't know what he's selling.
I wouldn't consider buying this for a second without seeing it first.
Like most sellers of second hand parts, the guarantee involves you doing the testing and complaining if it's faulty.

[brian_s]

Yeah it might be difficult to see it when people are claiming he's trading from outside the country, sounds legit


There was one on eBay last night but it got snapped up sharp!

An amc head might not be so expensive after all when you factor in the buying a second hand head, testing it etc and possibly being in the same position!

[sweep]

I have a pressure tested and skimmed head here im just not keen on posting.

[brian_s]

I have a pressure tested and skimmed head here im just not keen on posting.

Sent a pm