5 September
It has been a while a now. Well I have been busy and also acquiring expensive bits that I cannot do a lot with. I bought some crows feet spanners. These are great for doing up those bolts/nuts in awkward places such as the lower ball-joint to upright bolt that also needs torquing up.
At last I took some photos of the car on the ground as promised a couple of weeks ago. I was prevented by weather. Here they are.
I think that covers it!
24 September
Session 103 - Head inspection, etc.
I know I should have done this a while ago, but I was quite happy with the detailed visual inspection when I purchased the heads. Now more involved measurements where taken as detailed below.
I re-measured the valve heads. I measured 40.40mm for inlet and 36mm for exhaust approximately, which will not be that accurate and it is difficult to measure when they are installed and closed! I had been informed by V8 Developments that they were the oversized ones and I have no reason not to believe that.
I wanted to check if the heads had been skimmed at all, not that this would be a problem but I would need to know for compression ratio checks and possible valve to piston head clearance issues. Two measurements can be taken as detailed in the Rover V8 technical specifications to ascertain if any skimming of heads had been done. Measurement A = 22.94mm and B = 62.56mm which is spot on, so no skimming of these heads had been done. Next is to check that the heads are not warped and if they are whether this is in tolerance and can be skimmed. Great news, not surprising, the heads are true.
Out of curiosity more than anything I weighed the heads and both weight 8.8Kgs. The heads are identified as HRC2479 14 and 15.
Next up was to create an exact template of the inlet ports on the heads so that I can check if they match well with the inlet manifold I bought off email for £10! As these are stage III heads some port work would have been done and possible that the inlet ports on the head face increased, and I would need to get the ports on the inlet manifold increased to match, otherwise little point increasing on the head side.
Next up was to check the spring rating of the TVR items I bought off ebay, I am not actually going to use these but good practice as I am going to remove a spring from one of the heads to check to these are the correct springs. The TVR springs were found to have a free length of 49.57mm and the force required to compress to 40.40 mm which is the installed length was found to be 78lbs, this is known as the seat pressure. To further compress these springs by 12.11mm, which is the maximum lift, i.e. when the valve is fully open, is 193lbs. I calculated these measurements with the use of a drill press, digital bathroom scales and a block of wood. I was surprised by the specification of these springs, they do not appear to be good enough for my up rated cam, just goes to show, check, check and re-check. Standard single spring Rover items are rated at 76 lbs seat pressure and 165 lbs at maximum lift, but standard maximum lift is of course around 1.6mm shorter so requires less pressure for any one spring.
I spent around 90minutes doing all this.
26 September
Session 104 - Head inspection, etc, continues
Removed a valve spring from my head to calculate the spring rate. I was shocked, they were well down. I am a little suspicious that my measuring technique is not right. I decided to make a scale guide to put right next to the spring rather then the gauge on my drill press. I re-checked the TVR springs as a comparison. This time the TVR springs came out at 92lbs seat pressure, i.e. spring compressed to height of 40.40mm, then compressed to a height of 28.29 which equates to fully opened valve, i.e. 40.40mm - 12.11mm. This gave a reading of 192lbs. Now that is believable. Using this new method rated my installed spings at 71lbs seated pressure and 182lbs full opened valve, I am now convinced these are standard springs. Removing these springs I can see that the spring seats are machined for double valve springs. V8 developments did say that double valve springs were installed initially. I need to assume that the springs, retainers and collets are standard items, as such I need to replace the lot with known items, shucks!
It isn't all bad news though, as I was removing a valve spring I decided to remove another so that I could remove one exhaust and one inlet valve for closer inspection, i.e. the type used and the exact valve head measurement. Exhaust is 1.4" (35.62mm) and has a waisted stem and is marked DW501 and weighs 79grams. Inlet is 1.63" (41.40mm) this also has a waisted stem and is marked DW500 and this weights 86grams. The valve guides are bulleted also.
You can really see the porting with the valves out, someone with real talent did this!
Afraid spent another 1 hour missing about with this.
27 September
Session 105 - Head inspection, etc, continues
I had noticed that one of the top of the valve stem surfaces had a slight imperfection which looks a manufacturing fault. These valves are unused, that much is obvious so not a problem that occurred during use. The imperfection is very slight but as I am removing springs and a replacement only costs about £5, then a no brainer really. Today I ordered a new set of springs which are compatible with my cam, they are rated at 75lbs seat pressure and 200lbs at a lift of 12.7mm, a little under the piper specification but proven to be adequate in 1000s of installations, they are also manufactured by the same people as the valves, so I am going for it. I also ordered new spring caps and collets and a replacement inlet valve all from RPi. think I better sell my surplus items on Ebay now!
Took all valves and springs out of one of the heads in preparation for the new springs. My cam has a lift of 12.11mm (477 thou) and according to Des Hamil's Rover V8 book on Page 82 he suggests that should only have 11.7mm or 450 thou before the valve retain makes contact with the valve seal. I measured this for myself and found it to be exactly 500 thou or 12.8mm meaning I have a total clearance of 0.7mm (23 thou). Des does say on Page 83 that most engine builders doing work on these heads will machine down top of the guides to increase the gap between the retainer and top of the valve guide to 500 thou. I guess my Stage III heads called for this work.
28 September
My new valve springs arrived today along with my new inlet valve. I decided only to replace the one set of collets and kept all the retainers, cleaned all the valve and lightly oiled the stems. Cleaned the head completely, only surface dust needed to be removed. I spent around 90 minutes cleaning the head and installing the valves and springs. I am going to the the other head in a day or so when my bruised hands have recovered, if this is anything to go by I did not suffer removing the old springs but installing the new ones certainly has left my hands sore! Anyway still fretting over clearances, spring heights etc, I decided to measure all valves rather than just one. I measure a few times and no two measurements agreed, well when measuring down to 1 thousand of an inch, slightest change in the angle of the vernier calipers registers so I wouldn't take the variances across the valves as gospel also measuring with no spring installed is going to make a difference but when the spring is installed difficult to measure because it gets in the way and its seat is machined into the head. I decided to measure in imperial as the RV8 industry tend to work in these units! I spent another 90 minutes taking these measurements. I am going to take the measurement which gives the smallest clearance and check that is okay.
Okay here goes, with the head (number 15) in front of my with the exhaust ports at the posterior, we have sixteen valves in order from left to right, Ex for exhaust and In for Inlet valve the spring height would be in thousands of an inch (mm) would be: Ex 1592 (40.44), In 1587 (40.31), Ex 1580 (40.13), In 1589 (40.36), In 1600 (40.64), Ex 1596 (40.54), In 1609 (40.87), Ex 1606 (40.79). Minimum is 1580 (40.13), maximum is 1609 (40.87), a variance of 29 (0.74).
Next up, the retainer to the valve seal clearance, as before, Ex 560 (14.22), In 550 (13.97mm), Ex 539 (13.69), In 570 (14.48), In 546 (13.87), Ex 559 (14.15), In 557 (14.15), Ex 561 (14.25). Minimum is 539 (13.69), maximum is 570 (14.48) , a variance of 41 (1.04). These measurements which difficult as the seal is neoprene and compresses as you measure. Anyway, taking the minimum clearance of 539 (13.69) with a maximum advertised cam lift of 477 (12.11), i.e. worst case, this gives a clearance of 62 (1.58), plenty!
I know you lot like photos and I like taking them, so more pictures of head 15 at various stages work.
Photo of head 15 with valve gear completely removed, at this stage I had blasted the heads with air and cleaned with WD40. The blue things are the neoprene seals used on later heads, for those of you that messed about with older heads, you will notice that the exhaust valves of seals also.
Photo of the combustion chambers in all its glory, i.e. no valves installed, you can see the porting and bulleted valve guides. Bulleted and shorter guides take up less volume in the ports giving greater volume for gases, nice! Nice valve seats as well!
close up of one of the inlet ports
close up of one of the exhaust ports
Exhaust side port on side of head
Close up of one of inlet ports on side of head
Valve, valve springs, retainers and collets fitted. Now all that is needed is a nice roller rocker setup!
29 September
Session 107 - Head work continues
I know I said my hands were sore but I used the better one to compress the valve springs. I worked a little quicker tonight, being a little more familiar with the procedure only took me 1 hour to remove the springs, perform all the measurements like I did last night, removed the valves, gave everything a clean with compressed air and WD40. Inserted the valves back in and did not feel like putting on the new springs tonight. I shall probably do that tomorrow.
Head 14 :Spring length would be: Ex 1578, In 1578, Ex 1576, In 1576, In 1573, Ex 1579, In 1566, Ex 1600. Minimum is 1534, maximum is 1600, a variance of 6 .
Next up, the retainer to the valve seal clearance, as before, Ex 577, In 527, Ex 548, In 536, In 548, Ex 548, In 529, Ex 534. Minimum is 534, maximum is 577, a variance of 43.
All these variances were concerning me, I know trying to measure these distances prior to springs being installed is not going to be exact so I decided to measure from the top of the valve cap to the base of the spring seat on the head I finished yesterday, this measurement is little use but gives a reference to variance across the valves with springs installed at 75lbs of seat pressure and an absolute measurement taken using the depth gauge of vernier calipers should be interesting. It was interesting, in a good way, the maximum was 1555.5 (39.50mm) thou, the minimum was 1555 (39.49) thou, a variance of 1 ten thousands of an inch (0.01mm), wow, faith restored. At this point I would like to draw on some comparisons of things that measure 0.01mm but I do not know any, I was wonder if a cell would be a good comparison, any Biologists out there send me an email!
30 September
Session 108 - Head work, valves finished
Other commitments prevented me from doing more in the garage today but I did managed to spend 30 minutes, in which I managed to fit all my valve springs in Head 14. I am getting really quick at this. Did some calling around to check if I need roller rockers or whether standard rockers are sufficient as I need to buy these to complete my heads. Roller rockers are the ultimate but many people out there have stuck with standard valve gear with Piper 285s with no problem.The price difference between roller rockers and standard gear has got to be about £400, so I shall go the standard route and if I feel it is a problem then I can upgrade at a later date, easy enough to do. I think the money I save will be better invested in a really nice light flywheel. I am also going to get an ARP stud kit for the heads rather than use stretch bolts. Stud make more sense, especially if removing the heads on a regular basis. They are also better specification. Once I got these bits sorted out I need to install my new cam and then I can check the piston to valve clearances, with the higher lift cam. I have been told it will probably be alright but I am going to see if the clearance allows a tin gasket to be used rather than composite type.The tin gasket gasket is harder to get a perfect seal. Why tin gasket I hear you ask, well, because it raises compression by about 0.6:1 so a 9:75:1 engine becomes 10:35:1, meaning more power!
Go to October 2006