Engine rebuild costs

[maz1]

Hi guys how much would a decent mechanic charge to fully rebuild 325i engine. Engine has 171k on it still runs sweet be it a little tappety - just like every other e30 i've heard. Was thinking of a 2.7 build initially but just wanna no the difference in costs and performance.

Thanks

[march109]

Well DIY if my engine build is anything to go by you'll spend the best part of £1000 on a full M20 engine build, in reality it doesn't cost that much more to chuck a 2.8L crank in there if your going for a full rebuild, as the only extra costs will be the crank and spacer (rods are cheap as chips), if you start thinking 2,7L you will have the cost of timing headaches and a decking the block as well as the crank soit adds up a bit more.

A head rebuild would be much cheaper if you don't want a capacity increase and if the bottom end is fine, and they normally are they go on much longer withought work than the top.

If you arn't going the DIY route double or triple that for labour costs.

[beardymat]

i spent 2 bags on my 2.8 build but i did go for an uprated cam and a fully ballanced bottom end not to mention using genuine bmw for a fair few choice parts. will be interseting when i can find time to fit the bugger

[march109]

i spent 2 bags on my 2.8 build but i did go for an uprated cam and a fully ballanced bottom end not to mention using genuine bmw for a fair few choice parts. will be interseting when i can find time to fit the bugger

I won't tell you what mines at allready and I'm yet to turn a spanner on it!

[Ant]

I do 2.7 exchange units on various specs to suit, these range from mild to full on and pricewise between £2.2K and £3.5K, thats all new internals and based on an overbored seasoned B20 block to ensure its 100% pukka

I offer a full warranty of 12months/12K too, never had one back in 3 years or more trading on my own.

a DIY rebuild of your stock M20B25 will eat a grand in parts easily enough , plus labour and any go faster bits you add along the way.

TBH if your is tappety it needs a head rebuild before anything else, almost defo needs at least the ex valve guides replacing..........

remember, a good head rebuld with new valves/guides,rockers and cam will cost in excess of £1K on its own, done correctly

HTH

[maz1]

What would be the full spec for a mild 2.7 - including bhp and torque figures. Whats a b20 block?

[daimlerman]

B20 block is the 320 one.There are two bore sizes for the M20(6 cylinder)engine,at 80mm and 84mm.4 cranks were made,so capacities of (in round numbers)2ltr,2.3ltr 2.5ltr and 2.7ltr are available.I belive that Ant takes the view that boring out a 2ltr block to 84mm gives a perfect bore to seal new rings against.As Ant is in the business of building/repairing E30's this is the very best practice for an engine build and goes part way to explaining the costs he quotes.The beauty of the 2.7 conversion and the wealth of knowledge available on this site means that it is possable to build an engine that will give just what you require.I,for example,wanted a tough,torquey engine that was reliable enough and easy enough to drive to turn my non-petrol head wife loose in without worrying but yet enough fun to keep me entertained the important point is that the bigger capacity is all about torque,torque is what pulls you out of a bend,torque is what fires you past an HGV.It is possable to build an engine that pulls from 2000rpm to 5000rpm,swap in a spikey cam an that shifts from 3500rpm to 7000rpm,but remember that on a 3.64 diff 3000rpm is 75mph,so you pays your money and makes your choices.Seem to remember that my 2.7 cost around £1500,thats parts and machining and labour for the bits that I could not do myself.So paying Ant or a similar qualified person £700-£1000 or so more than my fiqure if you are unable to strip and re-build an engine yourself is a bit of a bargain.

[maz1]

Thanks daimlerman. What i'm after is a smooth engine similar to a 325i sport. but a bit quicker. Dont want to lose low end or gain a rough idle. Thats why if i lose smoothness i'd rather get original engine just rebulit rather than increase size.