Oil Pressure Oddness

[eeyoreish 815 1 Vehicles]

I had the alternator bearings changed while it was off so probably eliminates that. They didn't feel quite right and I thought (along with the knackered tensioner bearing) the alternator might be contributing to my mystery whine.

Cam journals worn? What's the answer there if that's the problem? As far as I can see there are no replaceable camshaft bearings.

[Sparky 2,581]

Not necessarily an issue worth looking at.  First off, get that tension checked!  With the right tools, you can adjust the tensioner without any dismantling.

[eeyoreish 815 1 Vehicles]

Yes, I'll have another look at the tension next weekend. If that doesn't change anything maybe I should try swapping a pulley off the TE engine to see if it makes any difference. It's a HC engine too and as far as I can see from Deroure it will be the same pulley.

[snowrx 112]

Looks like all ended well despite much worry, but if one was to revisit the oil pump gasket issue:

You can dry assemble the pump housing over the rotor/annulus  with a piece of Plastigage (don't know UK equivalent brand, a deformable plastic rod used to measure small clearances) and check the pump end float just like you would fitting crank bearings.  Then you can make an informed decision on gasket thickness, or grind the pump housing face to reduce end float.

What would sell on these forums would be if someone found a similar diameter (OEM?) rotor set that was taller and made a pump housing (or doweled spacer) to fit it.  The powdered metal innards could be had affordably, but a custom housing would drive up the cost. Said housing could feature a threaded port to prime the pump and oil galleys!

 

[peteyg 291 1 Vehicles]

@eeyoreish more than happy to have a look Neil, but not sure i'll be of much use. You're welcome to borrow my Krikit gauge which I've found perfectly good for tensioning the cambelt.

Pete

[eeyoreish 815 1 Vehicles]

Thanks Pete. Based on the advice here so far I need to investigate the belt tension first. Do you think I’d be able to get access to get the gauge on the belt with the engine in? If so then yes, borrowing it would be a great help.

[Sparky 2,581]

The Krikit gauge is very small.  You absolutely must use it correctly!  It's easy to get a bad reading.

[peteyg 291 1 Vehicles]

1 hour ago, Sparky said:

The Krikit gauge is very small.  You absolutely must use it correctly!  It's easy to get a bad reading.

You are right @Sparky but I'm on my 3rd Krikit- tensioned cambelt and so far so good (and that's not because the previous 2 snapped!).

@eeyoreish We can certainly give it a go Neil. I only need to get to the long bit of belt at the top and it should give you a ballpark to work from. PM me and we'll sort a time. 

Pete

[910Esprit 465 1 Vehicles]

If you are on a round profile tooth, why not just do it by frequency?   (endorsed by Lotus)  The twist 'method' is nothing more than an informal check for an experienced mechanic.

[Sparky 2,581]

Yup, I do all mine on frequency now.

[Clive59 106]

1 hour ago, 910Esprit said:

If you are on a round profile tooth, why not just do it by frequency?

I thought it was valid for trapezoidal teeth too? The Gates Carbon Drive app works really well.

[910Esprit 465 1 Vehicles]

Yeah I agree.  I use 'Carbon Drive' on my trap belt.  (I actually had a Lotus Burroughs gauge, but sold it when 'frequency' came more device accessible....)   However, Lotus explicitly recommended frequency for the round tooth profile, but I don't think they ever did for Trap profile, so I always think its a bit more of 'use it at your own risk'

[Clive59 106]

I saw an old post of yours and Geert, which was interesting.  is 114Hz still what you set your trap belt to? And assume that +/-10% gives plenty of latitude? I checked mine and it seems to run fine around 110Hz, any more and I got some whine.

[910Esprit 465 1 Vehicles]

I agree Clive, I run mine at about 107-108Hz

[eeyoreish 815 1 Vehicles]

So how exactly are people measuring frequency of the round toothed belt? I've never done it so interested to know how it's done and what app etc to use. I have an iPhone if that's a suitable 'tool'?

[910Esprit 465 1 Vehicles]

Download Gates Carbon Drive app to your phone (assuming its available on IOS)  If not, there will be many other instrument tuning apps that display frequency.   Rotate the crankshaft until the engine is at 30degrees BTDC (important).  Cold engine of course .   Then hit (a sharp  tap) the cambelt between the aux pulley and the inlet pulley with something suitable, I use the handle of a large screwdriver, its not too important as long as its suitably weighted and could not damage the belt.   Simply read the frequency from the phone that is being held in reasonably close proximity to the belt being struck.  Adjust as required then recheck....

Edited February 5, 2019 by 910Esprit

[eeyoreish 815 1 Vehicles]

Thanks, sounds simple enough!

So I'm rotating the engine clockwise as normal and not backing it off anti-clockwise at all? Do I drop/bounce the screwdriver handle on the belt or just give it a short, sharp tap?

[910Esprit 465 1 Vehicles]

Its super simple, I can't understand why anyone faffs around with gauges anymore, they always seem more inconsistent to me.

Rotate engine in 'normal' direction until 30 degrees btdc,  The advice is not to rotate these engines backwards, although I suspect that instruction originates from models with the semi-automatic tensioner (not yours).   You'll get a feeling for it, its a brisk tap, but with a solid object with enough weight to get a reading.   As you will see, the readings will be pretty consistent however you approach it

[Clive59 106]

I find just plucking the belt by hand works fine, as long as you have finger nails I guess. The Carbon Drive software seems very good at picking up even short plucks. I suspect it has a very sharp filter around the desired frequency range. 

[fjmuurling 53 1 Vehicles]

Frequency measuring should be done 30 BTDC with the timing dots on the inlet and exhaust cam pulleys pointing to each other, but not aligned.

The chargecooler pump impeller will be damaged if you turn the engine backwards.

Even if you turn the engine a little bit backwards (tempting to do when you overshoot the 30BTDC mark) will alter the tension of the belt between the pulleys and screwing up your measurements.

See the attached sheet from Lotus. (substitute Clavis Gauge for Phone app, Tuneit! etc).

sn_ef_p18a.pdf

[jonwat 334]

10 hours ago, 910Esprit said:

The advice is not to rotate these engines backwards, although I suspect that instruction originates from models with the semi-automatic tensioner 

And mechanical charge cooler pumps. 

[johnpwalsh 1,302 4 Vehicles]

Anyone got a link to the app. Original technophobe here. Running a Samsung J7.

[Bibs 10,253 4 Vehicles]

https://play.google.com/store/apps/details?id=com.gates.carbondrivecalculator

[Clive59 106]

John, if you go into the Play Store app on your phone, you can get it there. If you haven't used Play Store before, do so. It has all sorts of good stuff(and lots of crap of course). If you just search the apps on your phone you will find it.

[eeyoreish 815 1 Vehicles]

What frequency is recommended for the round toothed belt on the HC?