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Well... after wakefield today (much fun!), I started hearing a knocking noise from the motor, not like the tappet noise, but a deeper knock, starting under load from about 3krpm up. Fuzzlet sugested that low oil may be the issue, so i shoved in another 1.5L or so (it was lowww... ) but still the knock continues, it seems to have gotten worse..

The test i have heard for stuffed rod bearings is unplugging the spark plugs one by one.. if the knock stops when you take load off that cylinder, its screwed,

Well, i tried that and it seems like the front cylinder has rod bearing issues, as it stopped knocking when i unplugged it.



Here is a youtube video, not of my car, but of a BP motor with the exact same symptoms, to about the same degree as my motor has it

http://www.youtube.com/watch?v=hMWwk47s0ak


Oh well, Time to finaly do what i had always said i would do and rebuild my own motor.... an EVIL motor :>

On the other hand, what the hell, i only need one car (have two) and this gives me a great excuse to build a tough motor with a chunk more power

Sounds about right mate, low oil on track day outings is not a good thing. Hard cornering can lead to oil starvation...

A good excuse to build a new tough motor though

Well thats just a world of suck.

Did you get to mania for the cams yet?

Turbo goodness coming?

NMX516 wrote:Sounds about right mate, low oil on track day outings is not a good thing. Hard cornering can lead to oil starvation...

A good excuse to build a new tough motor though

Yeah, it was only 15km old, and i had put oil in it quite recently, so i figured the oil would be ok, and the pressure never dropped below 4-5 ish on the gauge... but it did not have much oil in it at all, though there was quite a lot of oil on the bottom of the motor, and everything nearby



Jeo: No, didn't get to mania yet, got the cams ready to go in though.

Nah, turbo would add so much more money on top of just getting the motor fixed up, where as slipping in some 2mm overbore (1.92L) 11:1 compression pistons, the cams i already own and some good gaskets and bearings etc, along with a bit of port clean-up and perhaps some nice valve springs... would be quite cheap

Is there such a thing as a more baffled sump for a BP? that seems like a good precaution... along with checking the oil with much paranoia

Also, any general hints for what to put into a good street/track NA engine?

I know someone is going to say go turbo, but its not worth the extra money/legal hassles, im just trying to pick up any KW i can when i rebuild it

daffyflyer wrote:Is there such a thing as a more baffled sump for a BP? that seems like a good precaution... along with checking the oil with much paranoia

Bugger. Have a look at the one Mactype has, may be worth asking him.

http://mx5cartalk.com/phpBB-3.0.2/viewtopic.php?f=57&t=30713&st=0&sk=t&sd=a&start=30

Sorry to hear your mis-fortune. The sound from that youtube clip sounds like the noise I had when one of the conrods on my SP bent.

Heat is the biggest culprit.

Damn didnt think that would of killed the engine. Even when turbo I used to check the oil every week, and when at the track would check at the start of the day

Yeah, im used to my other car, where when you'd change the oil after like 5000km you would find it had used about 100ml of oil

Also, who here has rebuild an engine, and what is your advice/am I crazy.

Im willing to learn, and i realise im going to need a machine shop to do a fair bit of work, but is this doable DIY?

I have never done engine internals before, but I have done an engine swap or two (working with someone else), do I have a hope?

Unless you have the know-how, books, advise and the right tools, I highly recommend against it.

I Disagree ....

I'd give it a go, Take your time, grab the factory manual, grab the right parts, find a good machine shop to do your machining (I use a repco shop here on the coast - well, used to, I think they have now closed..) take your time, take plots of pics and take your time.

Did I mention to take your time ?

Little tricks like oil Pump priming and Cam follower priming can save you a lot of worry, but you generally wont find those tricks in the manual, just in other members heads...

I've never done a 'modern' motor like the MX one, only dinosaurs (Holden / chev V8s, 6s and lots of BMC A-series / B Series, and a few obscure engines like a Lotus Escort and a 2-litre Cosworth.....) but they are all pretty much the same inside

If you dont feel up to it, then pay a pro .... or buy a second-hand engine and have a go at rebuilding that

Enjoy
J

Ok, i think I shall give it a go, its something I really want to learn, and its not like i need the car running, i can afford to take 6 months to build the motor if need be

Just ordered the aftermarket workshop manual from Mania, Wish me luck!