20 July 2013 - Fuel line plugged/tank back in

As the POR coating was being left to cure for a few days I still needed to do another dump run or two so as the LH tank was running fine with dieso last weekend I thought there wouldn't be any issues. How wrong was I?

Heading out to the refuse tip on Saturday morning I approached a 1 in 3 hill out of the neighbouring village and then started to lose power on the hill. Then the engine cut out. Oh dear. Fuel starvation. My sudden stop did seem to miff the guy who was up my butt up the hill but there was nowt I could do.

I managed to get the engine running again and made it to the dump and home again (7 miles) without any further issues.

Back home I started to strip the system down. First the fuel filter had not been changed for a while so that was swapped. The old one had a foam shroud over it for some additional insulation and once removed I could see that the filter was not tight and had been leaking slightly. So I cleaned everything up and replaced with new O-rings.

Gunge in the filter

Once the engine was fired up it normally takes 5 mins to clear the air out of the system and the fresh filter. Not this time. After 10 mins it was running better but some air continued to appear in the feed lines. Engine was shut down and I pulled the feed tube out of the tank. Trying to blow down it seemed a bit 'restricted'. This is what I found in the right angled section at the outlet.

Well that's blocked then!!

So this was the reason for the Tdi struggling before the drain down then the dieso in throw in there helped to flush even more to the point of the blockage?

The filler cap was also blocked pretty much. In the end I soaked it first in kerosene and then cleaning solvent. Also torched it in betweeen to see if that would burn the gunge out. Eventually after a second soak in solvent the vents cleared.

 

Cap started like this. Varnish and polymerisation

 

That'll clean the gunge out?

From now on I will restrict the the LH tank to 75% WVO. This will limit the polymerisation and also the varnish built up.

RH TANK BACK IN
Once the LH tank feed problems were fixed I could turn my attentions back to the newly lined RH tank.

Originally this wasn't due to be refitted until the following day but I was due to a local car show the next morning and as the weather had been a pretty steady 27-30 Deg.C since the coating was applied it was now rock solid.

Tank raised in position via a car scissor jack and a few lumps of wood and filled with 20 litres of pure dieso. No sign of any leakage after a few hours so....touch wood?

Here's the interior coating before the fuel was chucked it.

17 July 2013 - POR15 in da tank!

Well I arrived home to find the pint of POR15 tank seal from Frosts sitting on the doorstep. So I thought I had better get that poured in. Cure time is around 96 hours so the earlier I get that coated up the better?

The first FUBAR was to pour 500 ml of epoxy coating into the tank through the filler port AND LEAVE THE DAMN DRAIN PLUG OFF! Luckily the funnel spout I placed through the filler port is not over the drain but I still lost around 50-60 ml which ran over the garden table and then onto the patio tiles. Well at least they will never leak?

The remaining coating was mainly left to settle on the dubious rear wall of the tank and the joint around it. I never had to drain any excess off. What with the premature 'draining' at the start the entire tin was used to re-coat the interior of the tank over the existing coating. Now to wait for it to set, which with the thickness I have laid up will be around Sunday I should think!?

After 4 hours the coating seems to have spread out evenly so it appears that my cleaning regime with Tescos budget bio auto washing powder may have worked? After all I have coated it once before so the full POR15 'kit' would have been overkill.

13 July 2013 - Houston. We have a definite leak!!

RH FUEL TANK
After scraping the paint and coatings off the bottom of the tank the other day I took a further closer look last night. There is a definite leak. Not much but a weep around the offside lower seal all the same, so the tank has to come out.

The tank was drained down and I cracked all the screws this morning then dropped the tank (screws had only been on three years so no issues with them). I also realised this was the 'Bomag tank'. A std rear fill that I had modded to a military'ish spec to do the job. Not that that is an issue.

Firstly pressure washed after a spray of kerosene and then a stiff scrub with a brush. As per the base of the tank the paint peeled off some areas very easily. Poor prep on my part?

The inside looked in mint condition bar the grime residue from the WVO/dieso. To degrease and clean out the interior I added two bucket loads of hot water with bio washing detergent to cut through the grime then forced my hand through the filler and gave it another scrub followed by a rinse out with the pressure washer. Then repeat the whole thing again with more hot water/bio/rinse.

Looking at the internals after it had dried out there was nothing obvious that's causing the leak but the coating does look thin especially on the rear wall. This is a common point of breakthrough anyway. The fuel also seems to be coming from behind the lower section of the support plate at the rear so it is probably leaking from a pinhole, passing between the plates then leaking at the lowest point?

After the addition of the hot water etc. the paint coating came off easily and in the end around 50% of the old stuff came off. These areas were clean then sanded back with coarse paper to bare metal ready for some quality zinc primer. Two coats of Smith & Allens 'galvafroid' equivalent later it looked like this. Exterior grade black gloss to follow plus black waxoyl underbody seal on the four vertical sides before install.

The original interior coating was POR15 Tank Seal and last time I used a 950 ml can shared between both tanks. I will stay with the same stuff but I don't really need half a liter...but I will get it anyway as 250 ml is only £7 less! Still £25 a pop!? This will be here next week.

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As Trig's was temporarily down one tank I needed to get him running for the weekend. As the RH tank had already been drained of fuel (around 80% dieso) this was stuck in the LH tank after draining most of that down. I don't want to start the engine cold on high concentration of WVO (even if the weather here is 27-30 Deg.C at the moment).

I took Trig's for a quick dump run and he ran fine. This was the tank that seemed to be suffering fuel starvation on high WVO levels. So it must be a viscosity problem restricting the flow when this tank is used for high concentrations of WVO?

10th July 2013 - Bits falling off.......

Over the past three days Trig's has driven around 250 miles trudging back and forth to the office picking up a French colleague from his hotel on the way (he has a 'thing' about Land Rovers so did not want to disappoint). A far more thorough shakedown run that he has ever been subject to before. A few faults occurred on the way home yesterday....but Trigs trudged on regardless.

WOULD NOT START
Pulled up at the hotel and when I went to restart with a hot engine the starter would wind over but the engine would not kick. I had been running on SVO for a few miles so I suspected a fuel blockage.

Popped the bonnet and, yes that was the case. Switched back to diesel on the RH tank and after a few turns he started and ran. I need to investigate the fuel issue on the LH side (see below).

BONNET CATCH
When I went to open the bonnet one of the military catches broke. The central pin pulled through the retaining cap in the end so it was left flapping on the bonnet. I wrapped a bungie around it for the 30 mile run home.

When I returned home I put a cold chisel/vice/MIG welder to good use and fixed it. They are not designed to be 'servicable' Ha ha!

RH FUEL TANK
Looking under the LR before I headed home I noticed a small drip falling from the RH tank. Checking the 2p sized damp patch I found it was definitely diesel. There was a similar damp area under the mud on the tank. It is a minor leak but does look like another issue.

The twin fuel tanks were the first items to be overhauled when I started stripping the 109 down, back in 2009. Each tank was chem washed and epoxied inside and out with tank seal. I am surprised if that has failed but I need to investigate further.

Pic from 2009

LH TANK FUEL SUPPLY
The LH tank runs around 75% SVO (maybe more) and was working fine early this week. Once the engine has done 5-6 miles and is up to temp I switch over.

One morning was a little colder (not that cold as I have had the tilt up and the door tops off) and I noticed that it was suffering fuel starvation under heavy load. Flick to the RH tank and it ran fine.

So I have a few possible causes:-

• The fuel line is 6mm ID and uninsulated. Maybe change to a more insulating type of std fuel hose?
• I am relying on only the mech lift pump on the Tdi to pull the fuel over. Probably asking too much?
• Thin the SVO a bit more with a bit more unleaded?
• Tank CAV filter blockage. Doubtful as this was changed a few months back.
• Vent blocked. No. Vent taken apart and thoroughly cleaned this week.

Another issue to investigate?