My Flying Control Jeep - The Ongoing Story

The end of another long day tinkering with Jeeps! Checked out cylinder compressions on Jessie this morning. No 1 is significantly lower than 2,3 and 4. I reset the valve clearances which were a bit tight, but it is still low, so I suspect a burnt valve seat. At best, this is going to be cylinder head off and re-grind the valve seats. At worst, the whole engine block will have to come out for machining and new seats fitted, in which case I'll get some hardened ones fitted.

I went for another short test drive yesterday, and the mis-firing had returned within half a mile. It's ok at low RPM and low load, but still intermittently coughs at other times. So as soon as the Croft event is over next weekend, I'm getting the head off and checking the valves and seats. I've got about three weeks to get it sorted as I've got a date with a Canadian Lancaster at the end of August.

Because of the tight deadline, I decided to wait until after the Canadian Lancaster visit to Middleton St George before pulling the engine to bits, and trailered the Jeep to Teesside. The Lancaster has flown the Atlantic from Canada for a six week tour of the UK. One of only two airworthy Lancasters, it flew in for a big open day on the 28th. It is painted in the markings of the aircraft flown by Andrew Mynarski VC, which was based at RAF Middleton St George during WW2. Between myself and a friend, we took around 1500 photos.

Here's a few shots from the day.

On September 12th, the two Jeeps were swapped around in the garage to give better access to the engine on the M201. After being plagued by engine problems in 2014, it was time to strip it down and give it a good inspection and rework as needed. In my ownership, Jessie has driven over 12,000 miles, and I don't know how many miles before that as the speedo didn't work when I got it. The engine has a French rebuild plate on it from 1987, 27 years ago, and I don't think the engine had been touched since, other than the minor work I've done.

The first job was to empty the coolant. After placing a bowl under the engine, and a funnel under the radiator, the radiator drain tap was opened. After a while, the hose from the engine to radiator was removed, allowing the remainder to drain.

The next step was to start removing other engine components that would prevent the cylinder head from coming off or would get in the way. All the head studs were slackened off, water hoses removed, oil filter bracket, plug lead bracket, plugs and leads, coil and carburettor. After a gentle tap with a hammer, the head became loose, but not free.

I was able to drive some 1/16 ply wedges into the join, slightly lifting the head. It raised slightly, but was more tight at the rear. Over several hours and increasing wedge thicknesses, the head slowly lifted away from the block, but was still gripped tight by corrosion on the rear head stud on the side of the carburettor.

After lots of struggling, tapping the head back down to the block, lots of WD40 sprayed on, and lifting the head back up with wedges, several times over, it finally got to a point where it was virtually free. From that point on, I rocked the head up and down at the front, while applying slight upward pressure at the rear with wooden levers, and eventually it came free. The rusty stud can be seen in the picture below.

After the wood chips from the wedges had been vacuumed up, the engine was given a quick look over. The top of the block and the cylinder head looked fine at first glance, but will be inspected more carefully after a clean up. The valves also didn't look too bad, but it was difficult to tell with them still in place. The valves on cylinder number one were given a bit more inspection since that was the one with particularly low pressure. The cylinder bores were also given a quick look for scoring, and seemed to be ok.

By this point, my back was killing me. I'd been wrestling with the engine, bent over the fender, for several hours, so was about ready to called it a day at that point. Before I did pack up, I removed the intake/exhaust manifold, and tappet adjustment cover.

On October 7th, the weather was sunny and warm, so I opened up the garage and continued work on the engine. My valve removal tool was just tall enough, but I had to grind the end a bit wider to fit around the Jeep collets. Once all eight valves were removed, I was able to get a good look at the seats. All the valve seats look in fairly good condition, and I can probably get away with a light cut and lapping the valves back in.

This is the seats from the number one cylinder, the one that had low pressure. They are in good condition. The fault obviously lay somewhere else.

Ah, this could be the problem!! Number 2 valve from cylinder 1. Not looking too healthy is it?

The number 5 valve in cylinder 3 has also seen better days. They've lasted 27 years, so I guess that's not a bad life.

The other valves don't look too bad, and could be used again, but considering I'm replacing two, and don't want to go back in for some time, I'm going to replace all eight with new, lap these in, and keep the good removed ones as spares.

My gaskets and valve order turned up yesterday. Unfortunately, the eight that arrived were all inlet valves; so four were returned and the correct ones should be on their way! Along with that order was a replacement starter for the Ford, so at least one Jeep is back on the road.

October 17th was another sunny day, so the garage was opened and work on the valves began. To start with, I used the valve seat cutter to dress the valve seats, and then all eight valves were dropped into place in the block.

One by one, each valve was drawn on with a marker, around the contact area. The valve was then replaced and rotated a quarter turn and removed again. The marker was rubbed off where the valve was making contact with the seat. The rubbing area was central on all the valves, so I moved on to the next step; lapping the valves. The picture below right shows the first valve with grinding paste applied, ready to start.

It was a slow process, taking most of the day to go through all eight valves, firstly with the coarse cutting paste, then the fine paste. In the bright sunlight shining into the garage, they all looked good.

To be sure, I got the little compact camera out, set it on macro, and did some video of each valve and seat. After studying the videos, there are a few areas that look like they need a bit more work, so that can wait for another day.

I've had approval for my valve grinding, from my Jedi Engine Rebuilding Instructor, so I'm not far away from putting the engine back together again. I need to clean up the faces of the block and head, and also want to clean the exhaust outlets of carbon build up before the collets go back on the valves. A pot of Wellseal arrived in the post today for when the gaskets go back on. The only other thing is to clean up the head studs, so the head will go on freely.

Today saw the beginnings of the engine going back together again. The mating surfaces of the head and block were cleaned along with the valve ports and pistons. The inside of the cylinder heads were also cleaned out. I paid particular attention to the studs with the surface rust that had caused so many hours of frustration when trying to remove the head!

A little worn out rotary brush was exactly the right size for cleaning out the stud holes.

Here's the cleaned up head!

The head was test fitted to the block to make sure it wouldn't stick when going back on. Next came the re-fitting of the valves.

There wasn't much room to get the collects fitted to the valves, and I wasn't sure I was doing them right, working just by feel. By the third valve, I was checking the collects fitted the valve stem before I tried to fit them in the engine. Some needed a slight sand with some wet and dry before they would fit the recess on the stem.

Only a couple of collets popped out as I released the springs from the valve compression clamp, so out of eight, I didn't think that was too bad, and both went in easily the second time. However, with the fender still attached to the Jeep, I couldn't see if the collets were fitted correctly.

Fortunately my little digital camera was able to fit down beside the engine to get a picture of each pair of valves. As can be seen from the pictures, Numbers 1,2,3,4,5,6 and 8 were all sitting correctly.

Number 7 valve wasn't right, and by feel, I couldn't tell, so it's a good job I took the picture. It was removed, and I found the collets didn't fit in the stem groove very well. They were wet sanded until the fit was good and re-assembled.

After that, all the valve clearances were set to 0.016 thou gaps. The manual says 0.014 thou, but my engine rebuilding master said to leave them slightly over size by 0.002 thou to allow for bedding in.

The next free day I have should see the head go back on, and then the manifold and rest of the engine accessories can be re-fitted, then I'll be ready for the first test run.

With more good weather today, I couldn't let the opportunity pass, so got straight to work on the engine re-assembly. I bought some Wellseal gasket sealant a couple of days ago, and this was painted onto the head gasket and block, allowing it to go tacky before the gasket was added.

Once the gasket was fitted, the other side of the gasket was painted and the mating face on the head. They were left to dry too, and then the head dropped down onto the studs. Oil filter bracket and ignition lead support were added on top of the studs, then the nuts added and torqued up. The oil filter was tighted on next and the oil pipe connected.

The radiator to thermostat water pipe was fitted next, followed by the bottome radiator pipe. Manifold gasket came after that, with more Wellseal on the block and the back of the gasket, then the front of the gasket and manifold. This was then fitted and bolted up tight. The radiator bracing bar was fitted over the top of the engine.

Plugs were tightened up, leads fitted and coil fastened in and wired up. Carburettor was next with the throttle link and return spring. Fuel pipes after that and then air filter. Last job was to refill the radiator with a water/antifreeze mix. I use Prestone anti-freeze, the same stuff that was used in WW2 lives on!

"Jessie" fired up within half a second of pressing the button, far improved over the several revolutions it used to take before the engine fired. The idle was nice and smooth and pick up good. In the video, a combination of the camera's microphone and the sound bouncing around the garage makes it sound more like a tractor!!

A test drive will have to wait a little while, as Jessie is blocked in the garage by the trailer, but after seeing how easily Jessie started compared to usual, and the smooth idle, I'm confident that the engine troubles of 2014 are behind me.

Here's the first start after re-assembly.

It is good to see that you were able to resolve that oh so frustrating problem!

trevor

Well, hopefully sorted the problem! I haven't been for a test drive yet, but all the signs are pointing towards it all being fixed, and without the engine having to come out and any expensive machining on the block.

Test drive today. All was well.