E30 Zone

So it looks like our 2nd engine in 3 months is on it's last legs and it it was a horse you'd shoot it.

Our first M20b25 lasted some 14 trackdays and 3 laps at Cadwell. Its replacement quali and race at Snetterton and 2 days at Oulton. It then spat its coolant out and looks like it won't be coming back out to play.

So for the other racers out there, what sort of reliability do you get? We have baffled the sump but nothing else. So what's going wrong us or the engines or just bad luck.....

If the toss up is between having an engine blueprinted back to scratch or treating engines as disposable we need to make a decision before next season. We also need to learn how to fit and remove engines its getting an expensive pastime paying someone else. Besides how hard can it be. Wouldn't mind taking a look in one anyway to get a feel for how it works. Only way to learn shirely.

Buy an engine hoist and axle stands and get stuck in to engine changes, paying somebody £20 to £50 an hour (depending on where in the country you are ) to do pretty basic work is money that could be better spent elsewhere.

Only raced the 2.0, not the 2.5 but I guess its similar? No right answer on rebuilds, engine wise its always best to go with what you can afford, if you can afford the full monty then full rebuild with new parts blueprinting and stretching everything to the max your regs will allow. Should then give decent power as well as reliability.

Opinions/advice about stats varies, when we've ran with a thermostat in engines blow gaskets, with it out they don't, but only our experience other people swear by keeping them in. We keep the main surround bit in but take the opening/closing bit out. If you don't already have one, a new aircon radiator is also a good investment. Also decent quality heavy oil, lighter modern stuff doesn't seem to work so well (eg 20/50). New water pump.

For a best value for money refresh before you put the next engine in, drop the sump off and take the head off. Have the head pressure tested and give it a light skim to make sure it is true (assuming your regs allow this). As long as the engine seemed sound when in the donor and compression was Ok, change the bottom end shells as a precaution but leave everything else bottom end alone. Check oil gauze in the sump isn't starting to clog. New valve stem oil seals when you are rebuilding the head, the head set will come with these. Check the oil spray bar is clear when the head goes back together.

I have stroked my M20B25 to 2.9L and haven't had a problem yet. That being said, I haven't tracked it 14 times yet. We did all the work ourselves, beside porting and shaving the head, so we have a pretty good understanding of the engine (that's not to say that it won't break as it is a race engine).

Problems with coolant sound more like a fault with the engine acessories (such as the water pump), unless the head or head gasket failed, in which case you should be asking questions of your engine builder.

Good luck and keep with it. I have been asked several times whether my car is turbocharged after passing modern sports cars, so the M20 has a bit of poke and plenty of potential.

I have thrashed the crap out of an M20B25 for 5 years, 20 year old bottom end, 5 year old head with 20 year old running gear, no problems whatsoever. But I've never experienced oil starvation, which tends to cause most of the engine failures. That and cheap bearings.

Put it down to either bad luck, or you are just thrashing the hell out of the engines

Well as you say, its been on 14 trackdays, not sure how often in between, or continously, but thats quite a bit, and for a 20 year old engine, you cant expect much from them, how good were the engines you put it, did you have/know any history on them???

there are some decent ones out there, but then again there are some on their last legs....

Might sound like a basic question but how often do you change your oil? Original service intervals might be 8k or something like that, but for a car that is always raced/tracked it should be changed a lot more regularly - many folk change it every race. Make sure the oil pump is in good nick too. As MilLRat said, sounds like an ancillary issue for the 2nd engine. Also watch that you arn't downchanging to early and over-revving the engines, the rev limiter can't protect against this.

As far as I am aware, M20's are good tough engines (I did about 1000 track miles on mine with no bother at all, as well as being used on a daily commute - and that had 115,000 miles on it already) and should take a good thrashing. So it does just sound like bad luck as much as anything!

Thanks for the replies - I part own the cr with Lee.

Oil is changed on average after 2-3 outings.

We haven't been overrevving the engine.

The 1st engine was the original engine that came with the car. It had done 120k miles. The second and current engine was purchased off a guy from here & had done 80k miles iirc.

We have managed to source a race mechanic and he is coming to have a look at the car on Sat. He works on a 325 that runs in the Pre93 champ so has some good experience.

I just don't feel I can justify spending a £3k cash outlay £2k say, per annum on rebuilds for a "race prepped" engine. We haven't got through a full seasons racing yet and I would be more comformtable making the leap in 2011.

Yup, reliability is a lot more important than power when you are starting off, if you have a spare 3k spend it on track time/more races. Change all of the water/heating stuff (pump rad etc), a head set, big end shells, and go racing . Couple of hundred quid or so DIY. Good luck, what series are you in?

Thanks for all the replies. We are racing in the CSCC Future Classics got out at Cadwell and Snetterton with them this year. At Cadwell we managed a few laps before limping off the track, we finished at Snetterton. First race, 40 starters and we finished 26th. Very pleased with that.

Been doing a lot of reading about engines and how the work. Oddly quite excited about getting one in bits and getting my hands dirty.

How hard can it be ;)

fieldl wrote:Thanks for all the replies. We are racing in the CSCC Future Classics got out at Cadwell and Snetterton with them this year. At Cadwell we managed a few laps before limping off the track, we finished at Snetterton. First race, 40 starters and we finished 26th. Very pleased with that.

Been doing a lot of reading about engines and how the work. Oddly quite excited about getting one in bits and getting my hands dirty.

How hard can it be ;)

Thats the spirit!! If you have a Haynes repair maunal, good patience and the correct tools, it's not that hard at all.