MR2 Roadster - A Tale Of Woe, Maybe...

[RYH64E]

Martin350 said:

I'm in two minds about that, but I am tempted to try it, I've got a new set of plugs...

I guess that any damage has already been done, even so, I think I'd take the head off before running it again.

[steveo3002]

one my cars was running with a duff plug and that sounded like a terrible bearing knock....sorted the plug and good as new

[Vitorio]

RYH64E said:

Martin350 said:

I'm in two minds about that, but I am tempted to try it, I've got a new set of plugs...

I guess that any damage has already been done, even so, I think I'd take the head off before running it again.

If it werent for that missing ceramic bit of one of the plugs i'd think it is worth a shot

But with that ceramic stuff being god knows where, he might end up doing more damage then there already is. and chances of it being magically OK are low..

Then again, if the head has to come off anyway, might as well... just be prepared for more piston/valve/head damage

[CoolHands]

Don't worry about it just stick new plugs in and try it. The old cap will be smashed to smitherenes and chucked out the exhaust; there'll be nothing left of it.

[Martin350]

Thanks for all of the constructive suggestions and advice, keep it coming!

steveo3002 said:

one my cars was running with a duff plug and that sounded like a terrible bearing knock....sorted the plug and good as new

I found that one the most encouraging, though!


Got frustratingly little done this evening; one final stud repair (drilling out and re-tapping one that snapped, it snapped again when I welded a nut to it and tried to wind it out) in the exhaust manifold, then power washed it out (still full of dust from the pre-cats removdal, and now a bit of swarf from the stud repairs), then blew it out with an air line.

I checked the air filter, it's not that bad but I'm a bit fussy, it'll get a new one.


I'm thinking that I'll check the other three big end bearings just in case, and if they're ok put the sump back on, oil in, cam cover on and then crank it over with no spark plugs in or exhaust manifold on and see if anything comes shooting out!

Edited by Martin350 on Wednesday 11th May 01:51

[Justin S]

If it had come out the exhaust it would have been sat in the pre cat,which it wasnt, so its still in there somewhere. Easiest thing is a bore scope to see whats happening. Most work is the head off. Least work and potential internal damaging is new plugs and hit the starter. Interesting 'project' whichever way it goes. I guess these run cambelts rather than chains ? Maybe if the head comes off its worth swopping that as well. Good luck with it.

[Faxo]

Id say the rattle is the ceramic from the plug as mentioned, I serviced an old Ka years ago, and the plugs snapped into the head. Used to smash the ceramic into the bore, then wind it over and blow it all out. This worked 9/10 of the times. On the 10th one, it left some ceramic in the bore, which embedded into the piston crown, and made it have a death rattle noise

[Paulr1980]

I have nothing to add other than this is like the car equivalent of where's Wally.

I think you should pop some new plugs in and fire it up. If it's done damage then you don't have a lot to loose!

[Martin350]

Justin S said:

If it had come out the exhaust it would have been sat in the pre cat,which it wasnt, so its still in there somewhere. Easiest thing is a bore scope to see whats happening. Most work is the head off. Least work and potential internal damaging is new plugs and hit the starter. Interesting 'project' whichever way it goes. I guess these run cambelts rather than chains ? Maybe if the head comes off its worth swopping that as well. Good luck with it.

Thanks!

I have had a look with a borrowed borescope but it didn't have the flexibility for me to see the whole of the piston or the bores.

These engines have a timing chain, and that seemed nice and quiet when it was running properly, so I'll probably leave it, even if the head comes off.


I'll try and get a bit more done after work this evening.

[Vitorio]

How about cranking it bit hand? If there is a big bit of ceramic left in the bad cilinder you would be able to feel that when hand-cranking right?

[Martin350]

I did a bit of cranking by hand when setting up for the leak down test, and there were no surprises then.
But yes, I think it's still a good idea and I will do that first.

[227bhp]

Martin350 said:

Today I took the cam cover off and carried out a cylinder leak down test, which revealed, surprisingly, nothing much at all.

Justin S said:

I guess these run cambelts rather than chains ? Maybe if the head comes off its worth swopping that as well. Good luck with it.

[227bhp]

Martin350 said:

Justin S said:

If it had come out the exhaust it would have been sat in the pre cat,which it wasnt, so its still in there somewhere. Easiest thing is a bore scope to see whats happening. Most work is the head off. Least work and potential internal damaging is new plugs and hit the starter. Interesting 'project' whichever way it goes. I guess these run cambelts rather than chains ? Maybe if the head comes off its worth swopping that as well. Good luck with it.

Thanks!

I have had a look with a borrowed borescope but it didn't have the flexibility for me to see the whole of the piston or the bores.

These engines have a timing chain, and that seemed nice and quiet when it was running properly, so I'll probably leave it, even if the head comes off.


I'll try and get a bit more done after work this evening.

I'm finding it hard to believe a borescope won't allow you to see the whole of the piston crown
You do have to lower each one down to the btm of the bore....

[Martin350]

Yeah, I had a look with the pistons at tdc and at bdc.
I'm struggling to get enough light down there to see the edges properly, and to get the probe angled where I want it, I should've made that clearer, but I couldn't make out any debris or damage from what I could see.


In the limited time I had this evening, I checked the other three big end shells, and as I suspected, nothing to report, but at least I know that now.

So I cleaned the old sealant off the sump and engine block, refitted the sump and put oil in.
Then I turned the engine over several times by hand, nice and smooth.
I then refitted the cam cover, unplugged the injectors and turned it over on the starter motor.
A good ten seconds or so and nothing came out, I think, and no horrible noises.

So, if I get time tomorrow I'm going to do a compression test, and if that goes ok connect everything up, put new spark plugs in, put the exhaust manifold back on and start it up! (I couldn't find an emoji for slightly worried face).

I suppose it's somewhere between and

Edited by Martin350 on Thursday 12th May 00:35

[Vitorio]

So the horrible noises might have just been the dead spark plug?

So far everything suggest that with fresh plugs it has a decent chance of doing just fine, but that does give us the case of the mistery missing ceramic bit, considering the pre-cats in the exhaust manifold.

fingers crossed mate! hope it all goes well.

[Martin350]

Vitorio said:

So the horrible noises might have just been the dead spark plug?

So far everything suggest that with fresh plugs it has a decent chance of doing just fine, but that does give us the case of the mistery missing ceramic bit, considering the pre-cats in the exhaust manifold.

fingers crossed mate! hope it all goes well.

Thank you.

I'm rather hoping the horrible knocking was just because of the dead plug, as steveo3002 has experienced and mentioned a couple of days ago.

But yes, still a mystery about the missing bit!

I'm, sort of, looking forward to getting home tonight and trying it out.

[jamiebae]

I didn't realise how cheap these have got now. They're great little cars, if rather lacking in luggage space...

[Martin350]

Yes, I think they are a terrific bargain at the moment.
I think in years to come nice ones will creep up in value.

The cubby holes behind the seats aren't too bad, easily enough for a couple of weekend bags, but as this is a second car it really doesn't matter.

[Daston]

How bad are these for rust? My bro-inlaw is hopefully going to be house hunting this year and wishes to get his first weekend car (he is mid 20s). Originally he hoped to have the budget for a 350Z but I think with insurance he is better off spending less on a nice facelift MRS.

[Martin350]

From what I've seen they aren't bad at all for rust.
I checked the MOT history for mine before I bid on it and there was no mention of it.
And my other half's 2004 model was very tidy underneath when she sold it last year.

Rear anti roll bars corrode, but it's not much to worry about.

From experience I can say that the MR2 is far cheaper to run than a 350Z.

There's the fuel for a start, especially considering a 350Z should be run on higher octane petrol.
Also prices of some parts like brakes and service items and any repairs are generally higher with the Nissan. And there's tax and insurance to consider.
A good MR2 should really be quite a cheap car to run.

As a weekend car I'd say the MR2, although very different and obviously not as powerful as the 350Z, is in some ways a lot more fun.
The MR2 is a sports car, the 350Z is a GT.