mx5cartalk.com

Hey guys n gals,
Was having a discussion with a mate the other day at a club motorkhana, and we were talking about if a motor went and died...

would you rebuild it?
or buy a spare and put it in?

what would be more cost effective?

I was thinking a second hand motor for our mx5's...because of their price, but when i had my old R33, If anything happened I would have rebuilt the RB25...
it would have cost more but I dont trust second hand/third hand turbo motors!!esp RB's....

or shouldnt I trust a second hand n/a motor?

If it happened to you, what would you do?
Discuss!

Cheers,
Chris

There is no debate on this I believe. The cost would be the determining factor in making a decision.

If you are on a budget then a replacement motor is the answer. Buying from a forum sponsor will mean you have a little more assurance.

If you have enough money to rebuild and plan to keep the car long term then a rebuild (with forged components if you want a performance gain) is the answer.

Hope this helps.

Les

depends on a few things like daily driver or not, track use or not, or serious engine failure or not. but you could buy a good spare now, swap it, & then refurb your current engine; or buy an adequate spare now, refurb it & swap, to retain the original engine in good condition, which might also be a consideration in terms of originality. if time off road isn't a consideration, then no need to buy a spare now, just respond if the original goes bang...lots of variables - depends on circumstances.

mine's not a daily driver, has low kms, & i'm not looking at the moment to build a forged component engine, so i'd do nothing. that said, i've thought about getting an adequte used motor to rebuild as a back-up or as a workhorse.

Cheers guys,

yeah mine isnt a daily - it is used for the track mostly. The only power mods are mania cold air, extractors and exhaust and i had the timing bumped slightly.

Also being a clubman, 93_clubman you make a good point about originallity of the car! thats one thing to consider now!

But yeah, mines got a weird noise...its louder than a noisy lifter, sounds heavier too...but only comes on at a certain time too, once its warmed up a bit.

Its not like the vid posted in that build thread, http://www.youtube.com/watch?v=hMWwk47s0ak nothing like that at all, gave it a slight rev and canrt hear it, but at idle is where you can.

So now she's parked up at mum n dads as I didnt want to drive it 20kms to mine.

good idea to park it up - next thing i'd do is try to id what that noise is - might be something simple, in which case good. but if it's potentially serious then you might just have caught it early enough to resurrect the motor for the future. in the meantime a good 2nd hand na8 or nb8a motor would make a good workhorse or development base.

well got my car back, seems it was a loose timing chain making the noise?

so all fixed, got it today and she hoots still and is actually alot quieter than I remember.


Can a loose timing chain cause long term damage?
or any damage at all?

MX5s have timing belts, not chains. If the belt was loose the timing would be all wrong, car would miss and misfire. I think the only noise you would hear though would be from the bearings in the tensioner or idle pulleys if they were worn or seized. Shouldn't cause any long term damage.

Its the tensioner which makes most of the the racket when its not tightened. I failed to tighten mine correctly on my last timing belt job. I wasn't able to drive it it made that much noise.

ah there you go, I learn something everyday!

Yeah hope its still all good!

good to hear it turned out to be minor - also the bp is a non-interference type motor so if the timing belt breaks there shouldn't be any damage to pistons, valves, cylinders or head.

quicky,

if you are happy with standard internals throwing in a second hand motor is a much much cheaper option then a rebuild.

Yes buying a second hand motor does have its risks, and yes buying one from a forum sponsor means you might get a better deal, but then you get the likes of my old NA, where I bought a second hand motor from a forum sponsor, got them to rebuild it, and it only lasted 115kms before it shat itself...food for thought...

So my car has a stupid gremlin inside it.

2 weeks ago, was making the same rattling noise coming from the engine.
I took it for a drive with my new semi's on and to get fuel - so went from lane cove, to the shell space station on epping road, came back, got home, massive rattle noise in engine.

next day start car, nothing, no noise - ran it for 10mins @ home, nothng.

Next day, took it for a longer drive, throughout lane cove, artarmon, st leonards, a good drive. no noise.

saturday I had to drive it, noise came back after around 15mins of driving.

sunday I race at EC - flog the arse out of it all day - no noise.

monday I drive from work to Hornsby after work - got to gordon (ryde road/mona road) and noise came back again. stayed this way till just after turramurra
got to hornsby at my oldies, nothing. no noise and since then there has been no noise.

does anyone have any idea on whats going on?
Ive got 2 track days in december which I dont want to miss out on

a few of us are stumped.

background - car is 1994 clubman 1.8
has mania cold air, full exhaust, advanced timing (always runs on 98oct) and has the water diversion kit
thats it really.

any ideas?

Are you able to replicate the noise while the car is parked and you adjust the throttle under the bonnet? Or is it only while you're driving around? Reason I ask is that I was getting an underbonnet rattle which I solved by padding the bonnet support arm. It was rattling around in the retaining clip which was partially busted! Also, if you can hear it while parked, then you might have a better chance of pinpointing where it's coming from.

Nup

It happens while driving - and even with bonnet up looking once its started