Engine rattle

[k. rogers]

I suppose really the only answer is going to be removal of the timing case to investigate further.

[Forumadmin]

An endoscope might see what is happening.
removing the cover is not too difficult.

[k. rogers]

This is interesting - tried the car again tonight and heard the tap on the timing cover again. Thought I would try to detect exactly where it was coming from with a large screwdriver up to my ear and it clearly sounded like the cam hitting the peg intermittently. So I wound it in as far as I could and let it out a minute fraction, much less than before, and low and behold the tap stopped. I assume from this that only the minimal clearance is necessary before the end float becomes a knock. At least now I don't have to start stripping the timing cover.

[David Morris]

Hi Ken,

That's great news! Well Done!

Happy Jowetteering!

David

[k. rogers]

Thanks David - I think I'm coming around to the idea that the noise I am getting is definitely down to camshaft wear and that without major work, the way to reduce it might be with careful end float adjustment and the zero clearances all you experts use on the tappets which should hopefully prevent the cam vibrating quite so much in its bearings. I will test drive the car over the next couple of days and keep you posted!

[jowettgeoff]

Sorry, but this is a rather belated post regarding this thread...

I thought I'd share an tip that I use in order to prevent the tappet ends dropping into the pushrod chest when removing pushrods. After removing the rocker shaft (taking care that the pushrods don't drag out with it)), proceed to remove the pushrods as follows. Hold the ball of the pushrod with finger and thumb of one hand, and with the other hand give the side of the pushrod adjuster a sharp tap with the egde of a spanner. This will usually break the 'suction' between the pushrod inner ball and the bronze tappet cap, and enable it to be removed safely. Once the pushrod is removed, I find it's very unlikely that the cap will drop out of the tappet of its own accord. Replacing the pushrod, don't dither! Just press it back with a light but decisive push

G McA

[k. rogers]

Thanks for that tip Geoff, I shall remember it for next time.

Have just test driven the Javelin and the 'cam noise' is much better - it would seem it is crucial just how much clearance is required to retain the end float: too little, ie none, gives you the alarming noise I was getting and too much gives you the intermittent knock I was getting on the timing cover. I'm sure there is still scope for improvement but it will be trial and error.

[Alf Heseltine]

Hi Ken, I've had a similar engine tap/rattle, I remember it turned out to be the Timing Chain with a spring link fitted.
This was fouling the timing case at the casting that takes the front oil seal, the cure was easy, I also turned the 'spring link' away from
the housing to gain extra clearance. Make sure if this link is fitted the open end is away from rotation. Hope this might help.

Alf

[k. rogers]

Thanks Alf, this is all good stuff to bear in mind if I have to end up taking the timing cover off. However, I would have thought this type of noise wasn't dependent on the temp of the engine (I could be wrong). Having given the car a good run today and got it nice and hot, I can safely say the rattle is worse when the engine is hot, despite me re-adjusting the end-play plug in and out several times during the trip.

The next thing I plan to do is to drop the sump and increase the oil pressure which I think is too low at 40lbs when hot at 40 plus mph.

[jowettgeoff]

Jowett rattles are a law unto themselves. When I was competeing with Jav/Jup, I held the view that the noisier the engine, the better it went. My best ever Jupiter engine sounded like a bag of spanners, but it went like the wind (well, figuratively speaking!).

I performed a significant engine rebuild on one of my Javelins last year, and you can now hear the tappets 100 yards before the car comes into view. I just can't track down the problem. Must try Drummond's 'floating rocker' theory.

Perhaps some things were just meant to be...

[Drummond Black]

Ken, re your idea of dropping the sump to adjust the oil pressure relief valve, firstly what is the oil pressure when the engine is cold ????
If it is 60 - 70 PSI then adjusting the valve will not produce more oil pressure when HOT..... It will just increase it when cold, which is not a good thing.

Lower oil pressure , in the above case, when hot could be worn bearings, Crankshaft and Camshaft. If you do drop the sump check the oil pump base paying particular attention to the cross pin that acts as a stop for the relief valve piston. I have discovered Roll Pins used here and this spews oil out at one hell of a rate once the oil gets warm. It must be a SOLID pin here. Worth checking if you have the sump off. I have fitted a new Camshaft and Followers to a low oil pressure engine and a 10 - 15 PSI increase was noticed,

Drummond

[k. rogers]

Drummond, I think I may have discovered the cause of both my 'rattle' and low oil pressure - incidentally, 50lbs when cold and 35 - 40 when hot at anywhere above 40mph. While the sump was off I had a look at a couple of big ends. One wasn't too bad but the other had considerable wear and was down to the copper in one spot. I haven't had time this evening to do a proper micrometer check to find the exact tolerance but I did reassemble the big end after cleaning all the oil off and it felt like there was a good few thou clearance. Luckily the crankshaft journals appear to be in excellent condition - shiny and very little in the way of grooves across their width, even the bad one. So I have ordered a set of 30thou under shells from club spares, the only problem being that they only have the wider notch variety and mine are the narrower type. They reckon I will just need to grind the notches to the right size - a bit of a faff, but shouldn't prove too difficult, I hope.

[k. rogers]

New shells now fitted - didn't have to file spigots down in the end as the con rods have been adapted to take either type of shell. Test drove the car last evening and all is quiet up and down the rev range.

[ian Howell]

Well done! And so simple on a Javelin - no need to remove the engine, no track rods in the way of sump removal, no twiddly bits attached to the sump. Why aren't ALL cars made this way?

Good not to hear (knocking)!