It's weird what pops into your mind.....

I woke up this morning with an idea, well more the idea of a place to look for the solution - complicated I know. Here's the twisted tale. I have an agglometer in the PI, a fancy name for a glass bowl and drain tap in the fuel filter. The idea for this is that you can see if there's any water contamination and drain the fuel. It also has the added benefit of being an easy way to drain off a small amount of fuel for starting a BBQ in true boys own dangerous cookery style - but that's another story :-)

Anyway, as well as the agglometer thingy I have a clear injector line so I can see what's happening there too. The result of all this transparency is that you see things you never knew were happening - phenomena that you'd be blissfully unaware of if you had a standard system.

What could I see?

Bubbles!

No not the one time monkey partner of the deceased King of Pop but bubbles of air/vapour in the glass bowl and the injector pipe. These baffled me - the system was not leaking, it was not cavitating, these were appearing from start up and through out running up to temp (pump temp as well as engine temp). So where were these bubbles coming from? They were worrying as the PI system has no way of bleeding air out once fuel has flowed passed the PRV and then at pressures over about 30 PSI the PRV won't bleed air.

OK so to the point - I woke up this morning and thought "I know where the answer to that is" and I went straight to the article Dave Pearson gave me which emanated from I think a 1990 Club magazine (2000 register maybe?). I had blogged about this in the past. There it was, failing motor shaft seals on the pump unit will allow air in as well as leak fuel out.

Now I have tested loads of pumps and found failed shaft seals on about 60% of them - I haven't looked for air ingress just fuel egress (which is more obvious when bench testing). So it seems highly likely that I can sort this out with new seals.

The article also provides some good advice on blue printing a pump, what and how to modify as well as what to leave well alone!

As I write this, I think I'm going to have to work through this article and do the operations it suggests with camera in one hand and blog in the other.

Whilst the Lucas pump will always be the weakest link I am determined to build a good 'un and run the little bugger to success - I am actually enjoying this.

As soon as work, family and life generally allow me the time in the garage to get some momentum on this I'll be OK.

So far my local hydraulics place have let me down on the parts I ordered but my new best friend Darren at Pirtek Reading is on the case. Today's idle though - I wonder if they can supply injector O rings?

Here's the article, scanned and blogged, I commend it to all PI owners, I just wish I could credit the source properly:-


Jason's Blog: More Lucas PI info - some pearls of wisdom here :-)

Comments

Post a Comment

Popular posts from this blog

More Lucas PI info - some pearls of wisdom here :-)

Over the years I've collected loads of info and books about the PI system, some better than others. I have always meant to scan and post up some of the more interesting stuff. I had my scanner working recently (but not on my spanking new Vista equipped PC - incompatible!) so I thought I'd scan a few things when I came across an old trio of A4 sheets held together with a rusty staple. They appear to be pages from a magazine article but from where I don't know. The last page has a few small adds on it but no clue as to where it first appeared. The opening paragraph suggests and owners club and the adverts are 1990 vintage - if you know where this came from please let me know and I'll give them the credit. Anyway, I scanned it and OCR'd it and here it is. I've been through it to correct the OCR errors but if anything doesn't make sense shout up and I'll check the original. THE LUCAS PETROL INJECTION SYSTEM - MARK II We are very fortunate to be able to publi
Read more

Worried about your trunnions? Relief is to hand!

Image
This is an bit of an infomercial for my mate Dave and his company Canley Classics. I know Dave well, I get most of my Triumph stuff from him. I sometimes work on the Canley Classics stand at shows, I own a Canley Classics T shirt and I have spent many hours driving Triumphs with him. Other Triumph parts suppliers are available, your mileage may vary and this may contain nuts. If you don't like what I say, ignore it :-) - It's a well know fact that the small chassis Triumphs have some design frailties. One of the more spectacular failures you can suffer stems from the front trunnions. When you get a failure here you can loose a front wheel - this isn't a good thing. Often incorrectly known as "trunnion failure" what actually happens is that the vertical link that sits in the trunnion snaps - it does this for a number of reasons, lack of maintenance, fatigue, corrosion, previous trauma, bad luck. Most often it's the nearside that goes, it's the side that
Read more

TR6 Clutch investigation (and interior replacement)

Image
Blimey, it's been a long time since I did anything serious in the garage. Having found myself with some time on my hands - I'm currently looking for paid work again - I decided it was high time I sorted out the TR6 interior. When I got the car it was the interior that let it down, a bit of a mix of old and repro trim, mostly past it's best, carpets stick directly to the floor and sagging seats. I did the seats immediately and then gathered the parts to do the rest - new carpets, underlay, a trim kit, H frame cover, clips and fastenings, glue, etc, etc. So it seemed like a "cheap" job as I had all of the big cost items. It was just time - and now I have that. So I stripped it all out and there it sat earlier this week, looking all empty and then I thought what a pig of a job it would be to have to take it all out again to fix the clutch! You see I've always had a tricky clutch in the car, not awful but occasionally when warm it gets quite "off/on"
Read more