Peter Carmichael Posted October 7, 2002 Share Posted October 7, 2002 All the main components have been checked from the engine and they have all come out OK, so a rebuild is on the cards. I will be fitting a new DVA Power head and I will need a new liner and piston. I will take the opportunity to refresh the obvious things like rod bolts and piston rings. etc. Link to comment Share on other sites More sharing options...
Miraz Posted October 7, 2002 Share Posted October 7, 2002 😬 Link to comment Share on other sites More sharing options...
Paul Bowden Posted October 7, 2002 Share Posted October 7, 2002 Good to hear. I am glad your crack has been passed fit for purpose 😬 😬 Link to comment Share on other sites More sharing options...
Alex Wong1697456877 Posted October 7, 2002 Share Posted October 7, 2002 Good news. *thumbup*Good luck with the rebuild, Peter. Alex Link to comment Share on other sites More sharing options...
caterhamnut Posted October 7, 2002 Share Posted October 7, 2002 Glad to hear that - one less thing to worry about. Can I have your other engine when you are done please 😬 😬26,000 miles in 13 months! angus@tinyworld.co.uk Link to comment Share on other sites More sharing options...
greg Posted October 7, 2002 Share Posted October 7, 2002 Excellent news Peter. Any changes to the spec? Greg, Q 86 NTM (Green 185BHP XF) Link to comment Share on other sites More sharing options...
John Howe Posted October 7, 2002 Share Posted October 7, 2002 Peter, that good news. Tech Chat wouldn't be the same without the various rebuilds of you and Arnies Seven's JH Link to comment Share on other sites More sharing options...
Peter Carmichael Posted October 7, 2002 Author Share Posted October 7, 2002 Any spec changes? Have been thinking about a bit more cam duration on the inlet side to see if there is any more power to be had, but I don't want to wreck the mid range. I haven't seen any engines on bigger valves getting up to bigger power levels, so I can't see myself going with bigger valves. Link to comment Share on other sites More sharing options...
greg Posted October 7, 2002 Share Posted October 7, 2002 Ah, Peter, I would assume that you have valves the size of dustbin lids (ie the biggest that would fit) - from what you are suggesting this is not optimal any ideas why? Greg, Q 86 NTM (Green 185BHP XF) Link to comment Share on other sites More sharing options...
Peter Carmichael Posted October 7, 2002 Author Share Posted October 7, 2002 No ideas really, just that the bigger valved engines haven't necessarily resulted in bigger power. Roger King is of the opinion that a bigger valve size could release more power. Rob Walker has bigger exhaust valves certainly, but his #1227 cammed engine peaks before 8000rpm. The valves I have been running for the past two years are 32.5 on the inlet side and 27.3 on the exhaust side. The inlets are 1mm bigger than standard VVC fare and the exhausts are standard size. I can't put the material back if it is ported for bigger valves, but I can see how the rebuilt engine responds to a change in cams and change back if it introduces nasties. Seems like the best course of action to me considering how good the engine was last time around. Link to comment Share on other sites More sharing options...
greg Posted October 7, 2002 Share Posted October 7, 2002 Thanks Peter, agreed that if you have a good design why change - it will be good to see the engine (and you) back again. My friend and I saw you talking to Hugh (I think) on the Cadence stand on Saturday (16.00 ish) and I said that I should ask how the crack testing was going. My Friend was then quite rude as he remembers pushing you car last year at Brooklands when the starter was broken. He suggested he could start a "I've pushed PC's car club" but then remarked that it would not be that exclusive. Got any timescales ? Greg, Q 86 NTM (Green 185BHP XF) Link to comment Share on other sites More sharing options...
Peter Carmichael Posted October 7, 2002 Author Share Posted October 7, 2002 I remember those days. I did go to the bother of getting a new exhaust made up to clear the race starter motor that has provided reliable service ever since. Apologies and thanks in equal measures go to all those who have pushed over the years. The other weekend, having travelled back from the Cadwell trackday, I traversed London in dreadful traffic which resulted in a lot of charge coming off the battery. Parked up outside Angus's place the car would not restart. I considered the gentle slope and decided to self-bump start it. A good shove to get it going, a leap up onto the rollcage, ooops, going towards the parked cars, thread legs over rollcage, reach down to grab steering wheel and correct course, slide into seat, engage second gear, pop clutch, VRROOOOM. Link to comment Share on other sites More sharing options...
Bricol Posted October 7, 2002 Share Posted October 7, 2002 I discovered a while ago the best technique not to perform with a self - push start. Open door of renault 5 (original shape) Get, out push like billy oh on the door and screen pillar. Get it rolling - leap in. Bang foot on clutch in preparation to slamming it in gear, 'cos the speed's dropping off Nut windscreen!!! Blasted pedals are very offset - but I didn't offset the same with my feet. Brakes were rather good as I remember! Bri Link to comment Share on other sites More sharing options...
Jason Plato Posted October 8, 2002 Share Posted October 8, 2002 Good news so far Peter , so are you going to assemble it yourself ? . I had great fun up in the bedroom last winter with mine , and its so satisfying . It also increased my mechanical sympathly - knowing how many hours went into it . See you next Sunday ...... Dave Link to comment Share on other sites More sharing options...
AMMO Posted October 8, 2002 Share Posted October 8, 2002 Peter Glad the crack testing went OK. There are various reasons bigger valves don't always work. I've seen some valves put in and the ports not modified accordingly. That's probably the most common. Good for the pub racers to tell their mates that they've got big valves. Obviously doesn't apply to you. The other is that the valve can be too close to the edge of the combustion chamber wall or cylinder bore. I had 33mm and 34mm valves made for the Zetec and on the flowbench found that the 34mm valve didn't flow any more with the 81mm bore of the 1800. However I'm pretty sure sure the bigger valves will work fine on a 2 litre engine with 85mm bore and modified combustion chamber. There was no room to modify the combustion chamber with the 81 mm bore. That's the problem with undersquare engines. Just not enough room for valves. Touring cars are around 88 mm bore and twin cylinder Superbikes around 100 mm bore. These can pack anything from 35 mm to 40 mm inlet valves. However, a good small valve head is usually better than a bad big valve head. My race bike had 36 mm intakes and 31mm exhausts. A German friend ran 38 mm and 32 mm valves. Our bike was so much faster, used to jump out of corners and sounded a lot crisper too. I think the camshaft route is correct. My road car is really nice to drive. I've had some new grinds done which I will put in soon. If it takes too much away from the bottom end I'll try somthing milder. Good luck with the development AMMO Link to comment Share on other sites More sharing options...
Rob Walker Posted October 8, 2002 Share Posted October 8, 2002 I am of the opinion that there is little to be gained in up sizing the exhaust valves from the stock 27.3 to 28.5 mm. If you consider that Dave Jacksons 1.6 has 26mm exhaust valves and produces a healthy 210 bhp and this is a ported stock 1.6 head and his power is still climbing at 8000 rpm. Dave wisely bottled out of giving more revs to see what the engine peaked at as he is running a standard bottom end. My own engine all steel 1.8 is peaking at 162lb ft @ 6200 & 230 bhp at 8000 which puzzles me as its fitted with 1227 / R500 cams and the R500 power goes on climbing to 8500 rpm ? I am tempted to fit some wilder cams this winter and see what happens ! Rob Link to comment Share on other sites More sharing options...
V7 SLR Posted October 8, 2002 Share Posted October 8, 2002 I went for the larger exhaust valves, but like Rob, believe it probably doesn't do much. I wanted to change the valves from the 2-piece Rover items, so thought I may as well go up a size. Nothing lost anyway... Glad the engine's coming back together PC. Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now