2 August 2006
Wednesday 08:15am, a knock at the door. Wow, cannot believe it, my engine has arrived. I only ordered this at 14:00hrs on Monday! Took just me an the truck driver to unload the engine and move into my little space left in the Garage. He was impressed how much I had squeezed in their already! The short engine on the crate and packaging only weight 90Kgs. Who said Rover V8s are heavy, they are not, its all the extra weight for a strong gear box , extra chassis bracing and other up rated parts that add more to the weight.
Anyway, I had to go to work now, so I shall have to wait until tonight before I can open my box and look at a shiny new engine.
Opened the box later that evening, wow, nice. Engine prefix starts with XM46D. Not sure what the XM means but 46D means it is a late 4.6litre V8 cross bolted block. My 285 degree CAM was in the box along with a crankshaft spacer required to use a Serpentine front end, as the crank nose would be too long. Also have a replacement CAM wheel for the timing belt for this camshaft but I am going to change the timing chain and gears for duplex one or at least a better quality vernier type. Fitting a duplex chain behind a serpentine front cover is a little challenging, I am watching a fellow build fettle things to make it fit. I am sure it will fit but I think I shall watch first! Why not the standard chain and gears. well the gear teeth are nylon and wear much quicker than billet or steel. The standard Chain stretches and the engine can then become 10 degrees out. Rover produced two versions of the serpentine cover; the intermediate which still had provision for a distributor but had the better crank driven pump. The later serpentine cover had no provision for a distributor as by 1994 all Rover V8 where electronic ignition without a distributor; the GEMS-8 system. Why the serpentine cover in the first place? Well space of course, it does not protrude out as much as the other covers. An SD1 cover will still provide enough clearance but the oil pump is driven by the camshaft which due to the gearing means less oil pressure, an old trait known by many old Rover enthusiasts.
7 August 2006
Another knock at my door, this time to pick up my old engine which I managed to sell to a guy from Cardiff via EBay. Took a while to go through the stuff and load into the Van. He is quite happy with the engine, well it is quite a good example after all, with it split down means that you can check no hidden surprises. I am happy also, my garage now has a lot more space with no engine bits laid out all over the floor on towels! The sale also means that I am not a lot out of pocket, about a half tank of fuel, 7 hours work and £25. I have also had some real hands on practice and leant more about the inner workings of a Rover V8, well it is not that complicated actually.
8 August 2006
Nothing exciting just spent 2 hours in the garage cleaning and cleaning my tools. The garage looks like an operating room again! Assembled my new engine stand, which is an overkill as it is rated at 350kgs but I wanted the type with four castors not three as they tend to wobble too much for my liking. I might get my short engine on the standard before the weekend, in its current configuration of block, crank, cam, pistons, con-rods, timing gear, it only weighs 90Kgs and that includes the pallet, box and packaging. (how do I know this? The courier label of course!).
Here's some technical diagrams of the engine design, courtesy of Rimmers.
Engine!
Exploded view of heads
Exploded view of main block
11 August 2006
Session 99 - new engine on stand
This morning I finally got the engine block out of the box and onto my engine stand. The main reason for my entry is the following photos showing the gorgeous engine!
Picture of the front of block. I was a little surprised to see that the camshaft timing wheel has metal teeth not nylon. I was told that they were nylon, is this an upgraded item.
Photo of the left bank, these are pistons 2,4,6,8 from front. On the right bank in the lifter galley, actually on the side of piston bore 3 you will see a red dot. This red dot indicates that this is a top grade block. When blocks are cast you can get shifting which results in the water jackets not running completely parallel to the cylinder bore resulting in a reduced amount of material between the jacket and the bore. Rover graded using ultrasonic testing. The blocks were graded as blue, yellow or red. Blue being the worst, yellow 2nd grade and red the 1st grade. Rover did try to use the red graded blocks for the 4.6 Litre engine but some were yellow if they ran out of red stock. They never used blue grade for 4.6. I think the 4.0 were usually blue or yellow. You might be lucky and find a red 4.0 but Rover tried to reserve these for the 4.6 of course.
Here's a photo of the underside showing the crank. This later block has the cross bolted caps as can be seen from the bolts going through the side and bolts on the top, i.e. 4 bolts per cap. Earlier blocks only had 2 bolts per cap and hence the crank could fret the block, especially when tuned to higher RPMs. If you are building a performance engine for fast road and or track, then it is essential that you source one of these blocks. Another option is the preceding interim block, which although was not cross bolted was the same block and had the bosses in place but not drilled. A simple engineering job to drill the bosses for the 4 bolted caps.
Another photo but looking from the front of the block. I have found out that the timing chain is a Hy-Vol type, hence the metal teeth rather than nylon on the cam gear. This chain is quite thick, about 17mm. Apparently this chain is better than a duplex type. I think I shall be keeping this timing gear setup.
An aerial view of the top of the block showing the lifter valley and you can make out the camshaft in the middle. Piston 1 demonstrated just about TDC (top dead center)
13 August 2006
Nothing too big tackled today, just installed my return fuel line under the car. Took about 90 minutes, well there was a bit of drilling required through panels and three chassis cross members and they all have to be straight. Also did some tweaking of the bends in the line to position exactly in line with the supply fuel line, you must know what I am like by now!
I bought a second-hand DTI gauge today. An old engineering one, imperial measurements but I only need to ascertain exact top dead centre on the engine when I install the ultimate fast road camshaft which will call for timing to be reset. I probably make other uses for it such as determination of run out on brake discs etc.
18 August 2006
Session 101 - Car is on the ground!!
A momentous occasion, I have moved the car of the stands and lowered to the ground. I spent about 15 minutes thinking through the best procedure and the safety aspects. Took just 5 minutes to lower to the floor with help from my son and my daughter's friend (don't ask!).
Now the car is on the ground I can torque those rear hub nuts (250ft/lbs). To torque the hub nuts requires a monstrous torque wrench which I had to hire for the weekend for just a 10 minute job. I torque up in stages (50 ft/lbs) not because you need to but because I was worried that the threads would strip, they didn't of course.
I am going to roll the car out of the garage over the weekend, why, because I can! I shall take some photos.
22 August 2006
British weather prevented me from risking getting the car out the garage so no photos yet! Today I picked up my second hand but unused V8 Developments stage III heads. I have a pair of old heads and have been comparing the porting on the V8 development heads with, wow, smooth and the ports are opened up quite a significant amount. Quick measurement of the valve heads seems to suggest the inlets are 41mm and the exhaust are 36mm.
I also sent back my Piper 285 camshaft supplied by RPI international, as this appears to be the camshaft for the interim serpentine front cover with distributor and I will not be using a distributor. I have been checking the camshaft profiles and there are differences between the two models. The Piper V846BP285 is 30/70 inlet and 73/33 exhaust. The four figures that describe the profile in order are the degrees that the inlet valve opens before T.D.C (BTDC), 30, the degrees the valve closes after B.D.C (ABDC) , 70, the exhaust opens at 73 degrees before B.D.C (BBDC), 73, the exhaust closes at 33 degrees after T.D.C (ATDC). This sounds confusing, Piper cams describes with aid of diagram by clicking on the technical advice from here. Note they have made a mistake, see if you can find it!
Valve lift is 12.11mm, I shall need to check the clearance between the valve spring retainers and the valve seals on the head, standard clearance does not allow 12.11mm.
Some interesting maths on the camshaft. The inlet duration is 30+70 + 180 = 280. Exhaust duration is 73+33 + 180 = 286.
Valve overlap, which is the duration when both inlet and exhaust valves are open, which is what causes rough idle, is calculated as 30 + 33 = 63. The higher this number the hotter the cam, the more power released but rougher idle. Hot cams can be tamed at idle by the use of hydraulic followers that have a bleed down feature, which reduces the overlap below a certain rev range, usually below 3,500RPM.
The camshaft timing is 280 / 2 = 140 - 30 = 110, and check the exhaust timing, 286 / 2 = 143 - 33 = 110, not surprising it is the same really! This is the point where the cam should be when piston 1 as at TDC. However, maximum lift has a duration which has to be calculated like TDC and the midpoint found, so likely to be timed in at 112, but please refer to the camshaft installation instructions.
Well this has been fun, hasn't it!
23 August 2006
Spoke to V8 developments regarding the heads to get some history, unfortunately I had wrote down all the numbers except the ones they needed which are stamped into the side of the heads, check this tonight and they have V8D249 28.5CC stamped into them, I shall call them tomorrow. Did take the opportunity to discuss the heads assuming that they are actually stage III heads. The springs, collets and spring retainers are heavy duty and used by racing spec engines up to 8,000RPM. I also asked about the 12.11mm valve lift and this should pose no problem for clearance between the spring retainer and the valve seals, apparently the clearance is 600 thou, which in old money is 15.24mm, so no problem. The guy I spoke to was pointing out that maybe the valve to piston head clearance might be an issue and to check that I can get away without installing pistons with valve cutouts. They do not deal with Piper cams so he was a little uncertain.
I spoke to RPI international who supplied my short engine and the Piper cam regarding any possible clearance issue. Good news I spoke to an engine builder who has installed many of these cams on the said engine and never had an issue with clearance, so that is the end of the subject.
24 August 2006
Spoke to V8 Developments at lunchtime and confirmed that these heads were produced as per a 4.6 Litre V8 specification. The heads are stage III and have been gas flowed. Combustion chambers have been equalized within 0.3cc. Combustion chamber size is 28.5cc. Casting marks are 14 and 15E. Valve head inlet diameter is 41mm and exhaust diameter is 36mm, which are standard stage III items. Seems to be some discrepancy with the valve springs though as V8 Developments installed double valve springs for a kent cam installation. These heads have heavy duty single valve spings installed. Although at first it may seem strange to downgrade springs, it is good practise to not install overrated springs for a specific cam, as this can lead to premature cam lobe wear. The guy I bought the heads off was intending on installing the same piper cam as me so obviously changed them for that reason.
The Piper 285 cam calls for springs that are single type and have an installed height of 40.4mm. Springs rated at 246lbs, 90lbs of seat pressure. Over the nose at maximum lift is 230lbs. If this does not mean a lot to you, then I am not far behind you on that! That is what I understand:
Installed height is the height of the spring when installed, simple but measuring the spring in the spring seat is tricky, unless you know the depth of the recess and you can then add this on the to length of the spring between this and the retainer.
Spring rated pressure is the amount of force required to completely compressed the spring from its uninstalled length, so this cannot be measured with the spring installed in the head. completely compressed is when the spring starts to bind, i.e. the coils are touching.
The seated weighting is the pressure the spring exerts on the valve seat when installed at the correct installed height.
Over the nose is quite literally the pressure exerting by the spring when the cam is on the nose of the cam, i.e. at maximum valve lift.
A redimentary method of calculating these springs rates can be done with a bench vice, a vernier caliper and a spring balance attacted to the claw of the vice.
A good site for explanation of valve springs can be found here
If camshafts mystify you still then click here for a good site explaining the principles behind them with animation also!
Anyway, it is high time I posted some photos, so here are some of my new heads.
Took a load of pictures of one head so I have not bothered taking photos of both heads, trust me they are the same!
Here's a photo of the head from the inlet port side. You can see how small the wall is between the middle two ports, on the standard head this is much thicker, these ports have been really opened up.
Here's a close shot of the middle two ports, significantly larger ports, you can also see the valve stems the smaller bulleted valve guides. These valve guides occupy less volume in the port allow extra volume for gases, lovely!
Aerial view of the head showing not only how clean this head is, and I have not cleaned it yet! Also you might be able to see that the springs are single and heavy duty type
View from the other side of the head showing similar porting done to the exhaust ports.
Closer view of one of the exhaust ports, again you can just about see the valve stem and guide. These guys now what they are doing, petty their web site isn't as pretty!
Finally the underside of the head showing the combustion chambers and valve heads. As you can see pristine also. The inlet valve heads are the larger ones at 41mm and the exhaust ones are 36mm (approximately), these are oversized, can go large but as you can see not a lot more before the inlet and the exhaust valve heads collide. I am happy with this size.
Go to September 2006