Trials and MGB problems

I recently discovered the MG’s fuel pump was dying, it has probably been on its way out for a while and it seemed to be a cause of the bad running experiences I’ve been having with the car. Certainly after changing it, the car felt great.

I went on Friday to an impromptu camping trip to the field at Hexham I frequent and decided to get there with the MG. It was obvious 10 miles into the trip the car was not 100% well as it wasn’t pulling up hills the way you’d expect it to. It was behaving very differently to how it has done in the past though and I decided to continue on. It was as if it was running out of fuel, if you gave the engine rest time, it would run again.

A theory formed in the back of my mind that there was an obstruction in the fuel system somewhere. When replacing the pump there was a *very* healthy flow syphoning itself out the tank and I’d checked the pipe to the engine bay so the area of suspicion was small.

Having made it to the field I spent the evening relaxing around a campfire watching films on the big screen. Saturday morning we started the jigsaw puzzle someone had brought in their van. By 11am we had the engine fitted and it was running around the field. Well worth a night sleeping in the van as the owner put it!

Having had that success, I had a look at the MG and concluded it was possible a pipe joint to the fuel filter just before the carbs was restricting fuel flow. I obtained a new piece of fuel pipe from a motor factors in Hexham and took the car for a test drive. It was popping a lot on the overrun and not revving very well high up the range but the fuel starvation issue didn’t seem there. I could help feeling something was wrong but there was little I could do there and little I could point at to as a specific problem to fix.

Next up was the daytime entertainment which was going to be a trials course since there was a trial bike there and it seemed rude not to. Whilst trying to find interesting bits of the lower steep part of the field to use, someone looked at the fenced off overgrown ditch at the side and an idea formed. There were suggestions it would be quite a project and take a few weekends to clear sufficiently to get a bike into it but after a couple of hours it was looking good. The ditch was seriously deep with some very steep sections but I was assured this was perfect trial material.

Sure enough, we got the bike down into it, and eventually back out again. This photo is a photo of the exit:

I’d taken a CR80 through it and didn’t do very well as I was too mechanically sympathetic, lost momentum and then things went really badly. Getting the trial bike up the section proved to be my favourite moment of the day, particularly when I scattered the spectators when I cleared the top of one section with the bike practically vertical. I did stop, still on the bike, although I did have to pull it out the side of the track :). I then made it through the hardest bit of the course with sympathetic use of the throttle. Those bikes have amazing power delivery.

Beer, more video, food and it was time to leave this morning. I packed up and headed into Hexham from the field over some pretty impressive hills which the car coped with. It was then onto the A69 and homeward bound.

As I approached Newcastle, the gauges were puzzling showing higher oil pressure than normal at high revs and the water temperature was lower than I’d have expected. Slowing down as I reached the western bypass, there was a lovely backfire accompanied by oil smoke out the exhaust. Not good but not unknown for this car. I went onto the Western Bypass but immediately pulled off as there was obviously something seriously wrong. Pulling away onto the roundabout junction I’d stopped at proved interesting with backfires and lots of smoke and I then hit some traffic lights on stop. At this point I needed somewhere to park urgently, took evasive action and cut across two lanes of traffic and into Wicks car park as the cockpit was now also filling with black smoke coming from the air vents. It smelt like burning oil and I didn’t think it was on fire but there was always the possibility. On a positive note the gauges did suggest there was still oil pressure.

Upon stopping and opening the lid on the smoking hole, er, I mean the bonnet, the first thing of note was the blown rocker cover gasket and some oil misted over the engine bay, second was the noticeably lower oil level and thirdly the lack of water in the radiator.

So that’s a Suspected Blown Head Gasket Report.

I suggested to the RAC they should send recovery, not a patrol but they have to confirm it can’t be fixed roadside and insisted it was done by the book. Thankfully I had one to read with me.

The patrol guy arrived and wouldn’t believe my diagnosis until he heard it started and decided that I “might be right”. He suggested towing a car of that age the 10 miles home risked ripping the front of the car off and I agreed so I had another wait for the flatbed.

Its now outside the house and when the wind dies down enough to not risk the bonnet being blown off, I’ll compression test it for fun, then take the head off and see how bad the damage is.

I suspect the fuel starvation on the way there set it up for the failure, the higher speeds kept it going on the way back but the slow down into Newcastle triggered it to finally let go. I just hope the block/head aren’t damaged by blowing gases between the cylinders.

Update: The wind died down and I took the head off. The head gasket was intact and not the problem and there was also plenty of radiator water present. The view with the head removed:

In case its not obvious to anyone, piston no. 4 should not have a hole in the middle. Time to take the engine out and put the other one in I think :/.