ENGINE PAGE 3

ENGINE PAGE 3

Home

Engine page 1

Engine page 2

Engine page 4

Engine page 5

Engine with new sump

These engines run hot. The sump that I fitted is non-original form. These after market sumps are deeper allowing for an extra 250cc of oil to be added. They are finned and made of aluminum. I've read conflicting arguments on whether they actually contribute to keeping the cylinder and top end cooler, where it's needed. I needed a new sump anyway so I fitted this type. Anything that may help in this hot Greek climate can't be bad.

Engine valve timing

This is the way that the engine valve timing can be set. The followers and their guides and the push rods are assembled. At the point where the two push rods are rocking back and forth on the cam and the crank being at top-dead-center, the timing chain is fitted. According to the book, to find TDC of the piston the cylinder and piston should be assembled. However I found it easier and probably more accurate without, because there is a point where the piston reaches TDC but the crank still swings 5-6deg without the piston moving up or down in the bore. This is due to the piston dwell period at TDC, which is a function of crank stroke and con rod length. True TDC is between that 5-6 deg swing of the crank. I found it easier to find that point without the piston and cylinder assembled. Having said all that, this isn't a high tech racing engine so this kind of accuracy isn't necessary.

Timing Chain

In this picture you see the new timing chain fitted and the timing chain tensioner. The chain link clip must be installed in the direction of engine travel, the official BMW reason for this was," In case of accident and resulting shock, that the clip does not release and subsequently the chain separates resulting in a destroyed engine"? After your accident and during your ambulance ride I'm sure you'd be thinking about whether the chain had separated. ( sorry, bad joke)

The chain tensioner is an R27 addition. It was an attempt by BMW to fix the rattly chain sound. The R27 was the first attempt by BMW to really fix all of those noises and vibrations associated with their singles. Prior to the R27 I suppose that the people just accepted it.

Engine bearing press

What you can do with a length of steel tube, washers and some threaded stock. Here I'm pressing on the 6204 C3 bearing. That's the bearing that fits into the timing chain cover. The C3 bearings have a little more free play than the standard bearing.

New piston

The new piston has three compression rings and one oil ring. This is the one-piece oil ring. There is also available an oil ring built up of three separate components. It's said that the three component ring beds in better during the first stages of engine run-in. This piston came with the single oil ring so I'll stick to that.

Cylinder

This is the cylinder after re-boring, honing and painting. The hatch marks from the honing are clearly visible. It has been bored to first oversize 68.5. I had the push rod tubes re chromed. The tubes can be drifted out using a length of aluminum rod or similar soft metal. On re-assembly it's a good idea to put a little sealer on the top end of the tube. This area is a potential oil leak area as the oil from the cylinder head is returned to the sump via the followers through these tubes.

Engine and cylinder

The engine is basically back together. The cylinder has been fitted and the breather valve to the front chain sprocket. The cylinder must be dropped over the piston so the piston rings must be compressed. I used my fingers to compress the rings "ouch" it's probably better to get a piston ring compressor to do the job. Also, by doing the job with my fingers I caught one of the rings on the edge of the bore and bent the ring. I had to buy a new compression ring.

	ENGINE PAGE 3
Home Engine page 1 Engine page 2 Engine page 4 Engine page 5			Engine with new sump These engines run hot. The sump that I fitted is non-original form. These after market sumps are deeper allowing for an extra 250cc of oil to be added. They are finned and made of aluminum. I've read conflicting arguments on whether they actually contribute to keeping the cylinder and top end cooler, where it's needed. I needed a new sump anyway so I fitted this type. Anything that may help in this hot Greek climate can't be bad.
	Engine valve timing This is the way that the engine valve timing can be set. The followers and their guides and the push rods are assembled. At the point where the two push rods are rocking back and forth on the cam and the crank being at top-dead-center, the timing chain is fitted. According to the book, to find TDC of the piston the cylinder and piston should be assembled. However I found it easier and probably more accurate without, because there is a point where the piston reaches TDC but the crank still swings 5-6deg without the piston moving up or down in the bore. This is due to the piston dwell period at TDC, which is a function of crank stroke and con rod length. True TDC is between that 5-6 deg swing of the crank. I found it easier to find that point without the piston and cylinder assembled. Having said all that, this isn't a high tech racing engine so this kind of accuracy isn't necessary.
		Timing Chain In this picture you see the new timing chain fitted and the timing chain tensioner. The chain link clip must be installed in the direction of engine travel, the official BMW reason for this was," In case of accident and resulting shock, that the clip does not release and subsequently the chain separates resulting in a destroyed engine"? After your accident and during your ambulance ride I'm sure you'd be thinking about whether the chain had separated. ( sorry, bad joke) The chain tensioner is an R27 addition. It was an attempt by BMW to fix the rattly chain sound. The R27 was the first attempt by BMW to really fix all of those noises and vibrations associated with their singles. Prior to the R27 I suppose that the people just accepted it.
	Engine bearing press What you can do with a length of steel tube, washers and some threaded stock. Here I'm pressing on the 6204 C3 bearing. That's the bearing that fits into the timing chain cover. The C3 bearings have a little more free play than the standard bearing.
		New piston The new piston has three compression rings and one oil ring. This is the one-piece oil ring. There is also available an oil ring built up of three separate components. It's said that the three component ring beds in better during the first stages of engine run-in. This piston came with the single oil ring so I'll stick to that.
	Cylinder This is the cylinder after re-boring, honing and painting. The hatch marks from the honing are clearly visible. It has been bored to first oversize 68.5. I had the push rod tubes re chromed. The tubes can be drifted out using a length of aluminum rod or similar soft metal. On re-assembly it's a good idea to put a little sealer on the top end of the tube. This area is a potential oil leak area as the oil from the cylinder head is returned to the sump via the followers through these tubes.
		Engine and cylinder The engine is basically back together. The cylinder has been fitted and the breather valve to the front chain sprocket. The cylinder must be dropped over the piston so the piston rings must be compressed. I used my fingers to compress the rings "ouch" it's probably better to get a piston ring compressor to do the job. Also, by doing the job with my fingers I caught one of the rings on the edge of the bore and bent the ring. I had to buy a new compression ring.