How do you break in an engine

[Guest]

I think the disagreement here is because you are taking the 325 head route which involves machinig and dismantling the bottom end. I am using 320 head, which is just a straight bottom end swap.

Granted 325 head will prob give better resutls, but I have the a shoe string budget.

[tbmw]

from what i've read you need to change the cam to make it a worthwhile exercise, standard cam and it is a waste of time

[Guest]

An ETA bottom end with a 320 head plonked on the top is not a proper 2.7 conversion and you won't even make as much power as a stock 2.5 lump so it's a pointless exercise.

I quote from TBMW 2.7 conversion article.

"885 (325) head has bigger ports and bigger valves, 42mm inlet and 36mm exhaust. However, the exhaust ports are similar size to the 731 (320) head and the inlet ports are a different shape as opposed to being radically bigger. The 731 (320) head is far from shabby and can flow enough air for 200bhp"

I thank you.

[Guest]

from what i've read you need to change the cam to make it a worthwhile exercise, standard cam and it is a waste of time

Yeah I would have cam'd it anyway, 325 or 320 head. I'll give you that one.

[Ant]

Ok , I'm gonna post on this one then

Edd is doing the budget build, his engine shouldnet him around 190 bhp and comparable torque, he freely admits to being on a budget and is not expecting a 210 bhp monster, what he want is a nice upgrade from the 130 odd bhp of his 2.0 mill, lets not flame him for that folks

the stock cam is not ideal for power, this we know but alpina cams were not much hotter TBH and @ least with a stock camshaft ther are no poor idle symptoms or peaks in the delivery.

Both methods are fine, as has been discussed at length before.

the 2.7 to avoid is the ETA bottom end , 325 head combo, 100% guaranted to pink, the chambers are the wrong shape for a good burn with flat topped pistons.

I feel another dyno day brewing once these are completed and run in .

be interesting to compare results VS build cost.

Ԛ£Ã”šÃ‚£Ãƒ”šÃ‚£ per bhp gained.. the 320/ETA hybrid should take the win by miles

[Quaser]

So Jimbob - which 2.7 route are you taking?

i know off the following:

1. eta block, 320i head with 325 cam and anxillaries
2. eta crank/rods, 325i head, block and pistons - all machined to fit!
3. etc block - 325i head - slightly skimmed!

I think mine was a varient of number 2!

Q

[Guest]

Just give me till the Summer and I'd be happy to be the 320 head 2.7 guinea pig on the rollers Ant

[Jimbob]

Mine is #2 on your list
Will get it on the rollers as soon as I've ran it in, then mod accordingly to whatever money I can scrape together

[Guest]

For the record, like Ant put it, I admit #2 on the list is the "proper" way of doing the conversion, if you are liking it to the C2 Alpina.

I however have just recently dipped my toe in the world of BMW (been a Vauxhall man otherwise), and am after a straightforward cheap fast rear wheel drive car to hopefully not dissapoint from my Astra GTE 16v.

[Quaser]

Any chance i could have a look at the spreadsheet you put together with Adam?

bmw@raj4.com

Maybe i can save u some Ԛ£Ã”šÃ‚£Ãƒ”šÃ‚£ (more then likley tell u to spend more though )

Q

[E30Adam]

Don't worry we've whittled it down to be as cheap as possible.

Not much more to be had on savings unless you can get free parts

[Guest]

This is what Ant was implying; the Alpina camshaft is not much hotter than a standard, therefore smooth idle and not a peaky delivery.

[Jhonno]

[Hijack]

Love your M5 Sal!!

Whats it like to drive?
[/Hijack]