Grrrrrrrr

[Daryl Gatenby <Daryl.Gatenby@domain.elided>]

 <<Grrrrrrrrrrr.txt>> 
Hi Gerry,

Like other digest members I concur that it is difficult to suggest causes for the noise you experience without hearing it. It is preferable for obvious reasons to look for the simple causes first. Isolation of the area where the noise is coming from would be the first step I would employ in a quest to stop it. Like other listers have said, this can be sometimes difficult. Stethascopes or hose pipes attached to your ear and contacted with various parts of the offending article/s can sometimes help identify the area where noise is originating. As previously said by someone else on the list however, all to often noise and vibration can be transmitted throughout the engine (and the entire vehicle for that matter) making it difficult to pinpoint. 

I would be interested to know whether the grrrr disappears at some point above 2800rpm. 

A few simple (and some perhaps not so simple) things to eliminate other than tranny problems that I can think of however are:

Power Steering Pump fluid level - these can go grrrrr when the level is low.

Driveline vibration - as described by another lister, U/J's, shaft balance, loose flange bolt/s and exhaust system movement can cause noise. 

Timing chain tensions - you said you recently had a chain and tensioner job done, if for some reason the chain tensions and or guides are not what they should be these will usually clank clank rather than go grrrr. Not that easily checked without having the front cover off though. Maybe not the first thing to look at though.

Front pulley fit on crank - If for some reason the Pulley is not tight on the crank (buggered key or keyway or both, split sleeve, loose pulley bolt or something) this probably wont go grrrr but could give a similar impression to worn bottom end bearings - a dull rumble maybe.

Water Pump & Jackshaft - You did mention that you had work done in this area. When waterpump gear teeth and/or J/Shaft W/P gear teeth experience severe wear they can go grrrr. I know you said that you had these components replaced recently but an experience I had recently after having replaced the same components shocked me. Within 5000KM of having replaced the W/P the gear teeth were completely shagged to the point that the two sets of teeth were incapable of meshing enough to turn the pump. Recently there have been a number of reports about this type of failure. The cause/s are hotly debated - especially by the parts manufacturers and supliers. Some say that the W/P gear teeth are soft from manufacture - in my case it seems that way. Others believe that when the J/S housing in the front of the block gets worn to a point where there is any more than about 5 thou clearance between the shaft and the block the W/P & J/S gears are starved of sufficient lubrication and wear out very quickly. I wouldn't go blaming your grrrr on this straight away though - it's not that common I'm told. But in any event do think about whether the block & shaft tolerances in this area were checked when the work was done. The allegedly faulty W/P's were supplied to various parts retailers by Unipart I am told. This one is not so easy to check but as one of the last things in the chain of elimination you could withdraw the W/P from the block and take a look at the gear teeth.

Exhaust Headers might cause a bit of a noise - probably not a grrrrr mind you - if they contacted the steering rod that goes from the steering collumn to the control valve. Some headers do pass very close by this component and the engine does tilt on its mounts towards the rod under load. Unlikely cause however and you would really feel it through your steering.

Ancilliary equipment bearings - Alternator and P/Steering bearing might go grrrr if they are not right. 

Viscous Fan Coupling - You did talk about this in your posting. Although more likely just to seize and drive the fan at engine speed rather than go grrrrr, a semi seized coupling might go grrrrr. I do know that it is possible to fit the wrong P/Steer crank pulley on the crank which can take the fan really close to the radiator. If the fan blades touch the radiator when they flex towards it at revs (especially so if they are going at engine speed) that could really go grrrrrr. I actually went grrrr when this combination of events occurred to me once. I think the MK 1 pulley is different to the MK 2 and shouldn't be mixed - so I'm told.  

Air Filter Box - These can really rattle if they don't have the rubber seal between the two halves or if the anything else is loose inside them. Do make sure the bolts and washers securing the filter box onto the alloy induction pipes are tight - if something gets sucked into the engine through here you are more than likely the one who will be going grrrrrrrr. I did when mine sucked a flat washer into number six. It was real flat when I lifted the head off to retrieve it but luckily no harm done. Probably not a possible cause that warrants immediate investigation though.

Distrubutor Drive Gear - I suppose these could go grrrr if they react the same as their similarly driven W/P counterparts at the other end of the Jack Shaft when they are really worn. I don't think these give much trouble though. They have a much better direct lubing system than their counterpart but they do drive the oil pump as well. Another long shot that wouldn't be my first choice.
 
I guess there's lots of things that could potentially go grrrrrrr in a Stag. I would be inclined to start checking for sources in an outward direction from the point where you have most closely identified the origin of the noise. I do recommend you check your P/S fluid level though (and all fluid levels for that matter) because the P/S pump really does go grrrrr when it's low on fluid. I have observed that sometimes when low on fluid and idling they don't sing out but bring the revs up a bit and then they do. Once the pump has the right fluid level however it shouldn't need topping up unless fluid is lost from the host of possible places it can be lost in the steering system. And when it does start making a noise you feel a periodic and/or constant loss of power assistance.

From what you have said in your posting on this matter I wouldn't be inclined to dive into the bottom of your engine looking for bad bearings just yet. You might like to check the end float in your crank though. This is pretty easy to do by just leavering against the front pulley forward as far as it goes (making sure that any movement is not as a result of the pulley moving in either direction on the crank) and then do the same the other direction. Any significant movement here (the regulations are in the book somewhere) because of worn or absent thrust washers could cause noise, but again probably bottom endish rather than grrrrrrrrrrrrrrrr. Easy to eliminate though.

 
Good luck.


Daryl Gatenby
Hamilton
New Zealand

73 MOD
97 Toyota Disposable

2