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I have reason to believe my short nose crank bolt is on it's way out.

The timing belt was changed about 20K kilometres ago, and the pulley has a slight inbalance. Most of the reading I have done says that the bolt should be changed regularly and to precise instructions to avoid failure... What are the chances of that?

I have ordered the bolt and key from mazda, and will replace it with locktite to specified torque and cross my fingers...

I'll also start putting money away for a big nose engine.

Has anyone seen a loose pulley in person? The wobble is only slight, but I assume the pulley should be dead straight.

Boags

Is this going to cause problems for your road trip?

Could the additional load of the a/c be causing this?

PT wrote:Is this going to cause problems for your road trip?

Could the additional load of the a/c be causing this?

Possibly to both...

The road trip is going ahead at this stage. I'm worried long term, not short term. I'm going to replace the bolt and key before I go though.

If it is wobbling now, damage has already been done, and new bolt and key is just a band-aid. It is not the bolt you have to worry about it is the keyway and the nose of the crankshaft !

Having seen how quickly the whole short nose crank thing goes pear shaped, I would not be driving any long distance with it, unless you have a tow truck following you

PT wrote:Could the additional load of the a/c be causing this?

I have aircon on mine but it never caused any grief. The Boagsie's aircon has only been in for a ferw days.

Boagsy.....i changed my short nosed Engine with a 91 JDM import one.......never looked back.

dríven on weekends only.....by lady Driver.

But in the sceam of things i hope its not what you are suggesting.

Sorry to hear that Boags.

The wobble on red5's pulley was pretty obvious with a timing light shining on it. The crankshaft nose was stuffed and the engine had lost considerable power.

The bolt on yours should have been replaced when the timing belt was done. I believe the reason is that the bolt thread deforms slightly at the specified torque to maintain that torque and it is thus a one time use only.

If you haven't lost power yet, it may be worth trying a new bolt and key. If nothing else, you'll get to see if there is any damage to the keyway/nose area. There is no need to Locktite it and that may make future removal impossible.

MX-5 Plus have big nose 1600 engines at reasonable prices.

Spot on JBT. My thoughts exactly. So far, no power loss. Certainly not any like Jan was describing. I'm going to get the bolt and key out and see if there is damage. If there is ANY damage I'll know the worst is true... If not, the road trip goes ahead.

Might be making the trip in a Lanos...

Can someone PM me how much Jan's new engine cost please.

Boags

Buy an NB!

As well as the crank bolt get the 4 bolts that hold the pulley onto the timing sproket.

I know from experiance that the loctite fix does work as mine has had th fix for a good 10-20 thousand boosted klms.
Reason i say to get those 4 bolts new is cause of my recent failure with them - not a fun exercise to take off loctited parts (had to replace all mine again, and wait for a week for the parts to come in).

The extra/over tension of the water pump belt is what i belive caused my failure - you may have over tightened the aircon belt.

Big insurance poicy to replace those bolts mate, cheap as chips and you'll already be down there anyways.

If you can turn the crank bolt with your fingers then you definately know the key and crank will be damaged - as to how much will depend on how long its been like that for. Mine was loose enough to turn with my finger and the key was shot the crank luckily was in pretty good condition (slightly damaged tho).

Dave

I would give the loctite fix a shot. Just make sure you clean the area well with brake cleaner before applying the stuff. I've seen a very bad wobble case; it was almost like a 1cm eliptical wobble. The owner said his mechanic told him he had a bent crankshaft. I reckon the mechanic knew squat about short-nose syndrome. Did you do the belt yourself?. The key could have been installed the wrong way round. When I had my belt replaced at 100,000km, I had the bolt and key replaced, loctited and torqued to spec. My car has about 185000km and I'm going to replace those items again when I do the next belt change.

One quick way to verify whether your timing is off is to use the dipstick in cylinder no. 1 and determine the TDC position relative to the 0-degree timing mark on the pulley.

Thanks for the positive words guys, I'm really bummed about this.

I will replace those other four bolts too Dave, thanks for the advice.

My pulley has no where near 1cm of wobble! It is only just not plum, but even a little bit off can't be good. Hopefully I've caught it in time.

Craig - I was looking at a grace green 98 at the same time as the Boagsmobile. The decision came down to whether or not I was going overseas after uni. What's better, a 10G car or a 20G car to pay for while you are a student? But, in hindsight I might have gone a different path...

red5's wobble was certainly noticeable and you didn't even need a timing light to see it. It was a shocker!

Her car had lost an awful lot of power in the stage that it had degenerated to - so assuming yours still feels gutsy then Shazza should be fine for the trip.

Sorry if I gassed you with oil on the Chrissy lights run :p

Yeah, you disappeared from view a couple of times... Rich under boost? When you had the foot in it was pouring brown smoke out.

The parts have to come from Melbourne so won't be here till Friday. Does anyone have a torque wrench which is new or has been calibrated in the last 20 years (unlike mine).

Boags

PT wrote:Could the additional load of the a/c be causing this?

Definitely, the ac clutch puts a large shock load on the key especially at higher rpm. Red5 had the same problem arise after having the timing set and then using the ac.

Sounds like another dodgy day then.

Andrew.

OMY005 wrote:

PT wrote:Could the additional load of the a/c be causing this?

Sounds like another dodgy day then.

Andrew.

I HATE that peoples cars have to breakdown for me to have WINGZZZZZZZZZ

But CEST LA VIE !!!