NC 2.0l...knocking noise

93_Clubman · Postby **93_Clubman** » Mon Jan 01, 2018 10:35 am

Maverick wrote:...short nose crank 1.6 NA, supposedly these disintegrate going by many forums etc. ...super reliable car. When mechanical work is done in a professional manner no problems...

My 1989 NA6 SNC went in 1998 when the car had only done about 75k kms. Bought it in 1990 at 3k kms from a Mazda employee. Car had only ever required minor & major services, which had only been done at GWS Mazda Springvale (the 1k km service) & Mornington Mazda (the rest of the services). So front of motor was untouched. Some did just go - only warning was a slight hum that morning when I started the car.

Maverick wrote:Just putting more information out there for other readers to be more informed on MX5s.

Likewise.

JBT · Postby **JBT** » Thu Jan 11, 2018 12:43 pm

Are there any updates on this?

Blesif · Postby **Blesif** » Tue Jan 16, 2018 11:00 pm

I have only just noticed this thread. What is being described sounds exactly like the noise that developed in my wife's series 1 Mazda 3 (2005). Its the same basic engine. The car had done about 115 thousand km at the time and was serviced every 6 months as scheduled so I wasn't impressed. I had three different mechanics have a listen and each was wrong. Two suggested bearings and one thought we were headed for a rebuild or replacement engine. Instead it turned out to be in the VVT where a pin can wear an eccentric hole. That causes the tapping. An occasional fault but for some reason is not widely discussed among the Mazda fraternity. This was 5 years ago so I'm hazy on the details.

Ghoti · Postby **Ghoti** » Mon Feb 12, 2018 11:01 pm

Ghoti wrote: He suggested I try Mazpro in Bayswater for a final diagnosis. Its booked in for 8 January...so we'll see.

Figured its probably time for an update.

Short story is Mazpro thought it could be the VVT, or possibly the inlet manifold runners. Wasn't overly confident of either and said that noise travels in an engine, so while it definitely sounds like the top end, it still could be the bottom end. Rather than spending money on diagnosis, recommended an engine swap and got quotes for me, suggesting Allmaz as the best deal. Their 'drive away' quotes wasn't much more than MX5 factory supply only and for possible same motor (MX5 factory 70,000KM, Allmaz 78,000KM).

Allmaz couldn't look at it until the 15th February. Still hoping for a less drastic resolution! Swapping the motor without knowing what's wrong with the old one doesn't sit well with me.

93_Clubman · Postby **93_Clubman** » Tue Feb 13, 2018 10:22 am

Ghoti wrote:Swapping the motor without knowing what's wrong with the old one doesn't sit well with me.

Agree, but if you decide to swap the motor this might be of interest: viewtopic.php?f=29&t=72761

Postby **NitroDann** » Tue Feb 13, 2018 10:31 am

The problem is that labour is so expensive that even if you did find out what was wrong by examination and it was a minor issue, its probably still cheaper to swap the motor.

Dann

bruce · Postby **bruce** » Tue Feb 13, 2018 11:47 am

Drive it til it drops dead.
Upgrade your roadside assistance for towing.

Ghoti · Postby **Ghoti** » Sat Feb 17, 2018 1:00 pm

Blesif wrote:I have only just noticed this thread. What is being described sounds exactly like the noise that developed in my wife's series 1 Mazda 3 (2005). Its the same basic engine. The car had done about 115 thousand km at the time and was serviced every 6 months as scheduled so I wasn't impressed. I had three different mechanics have a listen and each was wrong. Two suggested bearings and one thought we were headed for a rebuild or replacement engine. Instead it turned out to be in the VVT where a pin can wear an eccentric hole. That causes the tapping. An occasional fault but for some reason is not widely discussed among the Mazda fraternity. This was 5 years ago so I'm hazy on the details.

Dunno how I missed this, but what you are saying is what the first "non-Mazda" mechanic suggested. As he had not done these on Mazda's (old school mechanic) he suggested I go to a specialist such as Mazpro.

Anyways, its with Allmaz now. Waiting for diagnosis but they did mention VVT and Bearings as the most common causes. Crossing fingers for now

Mr Morlock · Postby **Mr Morlock** » Sat Feb 17, 2018 2:15 pm

I wonder if Bruces recommendation is not far off the mark what to lose? . By and large getting engines pulled down, pulled out reconditioned cost quite a bit of money.

Ghoti · Postby **Ghoti** » Mon Feb 19, 2018 11:01 pm

Mr Morlock wrote:I wonder if Bruces recommendation is not far off the mark what to lose? . By and large getting engines pulled down, pulled out reconditioned cost quite a bit of money.

I really don't enjoy driving a vehicle that turns heads due to the clanking sounds it makes. Its not needed for transport - its really about enjoying the drive. Driving my "fun car" as is really isn't an option for me.

Maybe I'm too "old school". I would much prefer a fix to keep things purring rather than simply driving it in ignorance until it drops. I understand labour is now a larger component than parts, and that diagnosis costs may be better spent as replacement costs. That said, if the car could be repaired for (say) $1,000 now vs a premature $4000+ engine replacement some time later, the repair may not be so silly.

Of course some folk have suggested to trade it and lease a new one as fixing the engine is no guarantee against gearbox issues, or diff, or body etc. But that's just a far larger commitment than I'd want to make on a 'fun' car.

bruce · Postby **bruce** » Tue Feb 20, 2018 12:49 pm

It won't cost a mere thousand to fix. How much have you already spent on getting it looked at?
Perhaps try a thicker oil or an additive to quieten it down.

Ghoti · Postby **Ghoti** » Thu Mar 01, 2018 11:22 pm

bruce wrote:Perhaps try a thicker oil or an additive to quieten it down.

That was the solution employed by Mazda, well, more precisely, they put in an oil additive and suggested it would eventually quieten down.

In the meantime we appear to have arrived at a diagnosis. Took the car to Allmaz who said it didn't sound or behave like a big-end bearing noise and they suspected something timing chain related. After removing the rocker cover to inspect, the timing chain (and guides, and tension) were just fine. What wasn't fine, however, was the connection between the VVT and the camshaft. The camshaft rotates quite markedly, independently of the VVT Actuator. Needless to say, it shouldn't do this!

Anyway, he's fully booked for next week so the repair is scheduled for the week after. Looking forward to having her back at home and going for a blast through the hills.

93_Clubman · Postby **93_Clubman** » Fri Mar 02, 2018 12:13 pm

Relieved to hear someone has been able to identify the issue, or at least an issue that is likely to be the cause, & good that it sounds like a simpler fix than that feared.

Mr Morlock · Postby **Mr Morlock** » Fri Mar 02, 2018 3:45 pm

blesif and JBT both mentioned the VVT as a possibility. Just taking the cam cover off is an easy task ... Hope it's an easy fix. I would be looking at the Mazda service manual just to see if there are pointers to the problem.

Ghoti · Postby **Ghoti** » Sat Mar 03, 2018 11:40 am

Mr Morlock wrote:Just taking the cam cover off is an easy task ... Hope it's an easy fix.

I guess what I referred to as a rocker cover is more correctly called a cam cover - I'm more used to the old push rod days

. Yes, easily removed and I am disappointed Brighton Mazda didn't take the trouble.

Easy fix...well, not really. Apparently the timing chain cover need to be removed to access the bold that attached the VVT to the cam. That requires removal of the crank pulley, which to access needs radiator and condenser removed. While I figured you should be able to get to it with a socket and breaker bar, I am told the issue is torquing it back up.

Bottom line is its still a darn-site better than an engine swap!