Iain T Posted May 26, 2021 Author Report Share Posted May 26, 2021 Latest news: Made a 3mm thick stainless steel fan belt bracket so I can now fit the new belt. The old bracket was way too long and didn't have enough adjustment. Changed to 7B's and checked needle and jet heights were the same and centred. I found with 20/50 oil in the dash pots there was a lot of resistance to the piston so I changed to 3 in 1 which is the lightest oil I have. The resistance was a lot less. Went for a spin today and there is a noticeable inprovement in the afr readings. Cruises around 14 and down to 12 on full throttle. Early days but much better than when I previously had the 7B needles in with 20/50 oil. Anybody tried British rape seed oil in the dash pots? Iain The Bastock cam made 112bhp and 120 torque but with a standard head. Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 26, 2021 Report Share Posted May 26, 2021 dont know what 3 in 1 viscosity is like when its hot but the damper is to solve flat spots on acceleration cant see that using cats pee is of any purpose but your on a mission of trial and error if the damper is working its supposed to give a good resistance to lift , but the vacuum has enough oomph to move it quite quikely Pete Link to comment Share on other sites More sharing options...
Iain T Posted May 26, 2021 Author Report Share Posted May 26, 2021 48 minutes ago, Pete Lewis said: dont know what 3 in 1 viscosity is like when its hot but the damper is to solve flat spots on acceleration I just wanted to try a lighter oil to see if it made much difference and it certainly does. The slightest of acceleration and the readings momentarily go up slightly then reduce to normal but on moderate/hard acceleration it's around 11-12. With 20/50 hard acceleration was around 10-11 on the afr meter. On feathering it's now around 15-16+ which I think is fine. I thought changing the oil shouldn't make a difference to the afr at a constant speed only on acceleration by stopping the piston rising. If we wanted perfect readings then change to throttle bodies! As you say trial and error with a modified engine. It does drive and tickover nicely but I do need to take it for a longer run. Iain Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 26, 2021 Report Share Posted May 26, 2021 I might have an avid hate of 3 in 1 in dashpots but its stability when hot would worry me ATF would be better as a lower viscosity and heat rated Pete Link to comment Share on other sites More sharing options...
Iain T Posted May 26, 2021 Author Report Share Posted May 26, 2021 20 minutes ago, Pete Lewis said: ATF would be better as a lower viscosity and heat rated I forgot I have some atf I use for the Type 9 box. I'll suck out the 3 in 1 and replace it. Thanks for reminding me! Iain Link to comment Share on other sites More sharing options...
Iain T Posted May 26, 2021 Author Report Share Posted May 26, 2021 No it's not atf its 75w90, no idea if that will work? Iain PS Just googled and 75w90 gear oil is the same viscosity as 10w40 engine oil. Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 26, 2021 Report Share Posted May 26, 2021 probably cork the damper up it needs to lift an EP might take some overcoming but youve got a week to prove this out the clocks running Ha ! Pete Link to comment Share on other sites More sharing options...
Iain T Posted May 26, 2021 Author Report Share Posted May 26, 2021 26 minutes ago, Pete Lewis said: but youve got a week to prove this out the clocks running Ha ! Challenge accepted! ⏳ Link to comment Share on other sites More sharing options...
Iain T Posted May 31, 2021 Author Report Share Posted May 31, 2021 On 26/05/2021 at 15:52, Pete Lewis said: but youve got a week to prove this out the clocks running Ha ! 75w90 seems OK and as you say will retain viscosity better than 3 in 1. It did seem thinner than 20W50 engine oil. Iain Link to comment Share on other sites More sharing options...
Iain T Posted June 13, 2021 Author Report Share Posted June 13, 2021 I relented and went to BD Engineering for a rolling road tune (£165 and highly recommended). The best result was with 6J needles, soft damper springs and 20W50 oil. Correct me if I'm wrong but this is the standard Mk1 setup? As I said mine is a twiddled Mk2. The afr readings are good throughout the range, mild and WOT. With 270 degree cam duration and 260 thou in/ex lift the torque is good at 1500rpm+ with 119 lbs/ft max and 108bhp. I think the cam is now the limiting factor as power drops off a cliff at around 4800rpm. But then the car is very driveable, starts fine and at the moment behaving itself (see clutch post). I very much doubt if I will approach 5000rpm so I'm not worried! Iain Link to comment Share on other sites More sharing options...
Nick Jones Posted June 13, 2021 Report Share Posted June 13, 2021 What cam is it? What exhaust manifold? The standard Mk2 cam is 270 duration though much less lift and the factory standard engine I did have in my Vitesse was happy to rev to Smiths both when still on carbs and later when injected. That made 120bhp when injected but also had a bit of head work and a 6-3-1 by that time. So maybe a bit surprising that the cam would be the limiting factor, unless it’s timed retarded? That said, the engine in my GT6 which is built as a Mk2 with an alleged factory Mk2 cam is much less keen to rev though it is very torquey and willing low down. Nick Link to comment Share on other sites More sharing options...
Iain T Posted June 13, 2021 Author Report Share Posted June 13, 2021 15 hours ago, Nick Jones said: What cam is it? What exhaust manifold? It's a billet Newman cam basically a standard duration but higher lift on both inlet and exhaust. The exhaust is Phoenix 6-3-1 with wheelbarrows. I'll check the timing but BD said he set it at 13 degrees. The cam that was in there was a TR6 PI from Bastock. I've measured the lift at 280 thou but don't know the duration. I assume based on the lift and the bumpy tickover it's 290ish. The 6J and 7B needles are both about 50 thou at the bottom. The 7Bs with a slightly thinner taper didn't make any difference to the power/torque and ran rich. Obviously standard 6AC where way too lean. The head has been gas flowed including valves and port matched so it should breath easier. It spins up a treat and has a very flat torque curve about 105lbs/ft at 1500rpm to 119 at 4800. The Bastock cam made 112bhp and 120 torque. Link to comment Share on other sites More sharing options...
Nick Jones Posted June 13, 2021 Report Share Posted June 13, 2021 TR5/early 6 cam is 280 duration IIRC, but has a lot of overlap. It needs a throttle per pot to play nicely really, but then it was designed for use with ITBs and sequential injection. I meant cam timing rather than ignition timing, retarding the timing tends to move the power/torque down the rev band. If you are happy with the way it drives, just enjoy it 🙂. Mine flattens off about 5.5k when cam specs say it should be good for at least another 1k, but in practice I only ever notice on the track and I only do that about once a year…… Nick Link to comment Share on other sites More sharing options...
Iain T Posted June 14, 2021 Author Report Share Posted June 14, 2021 11 hours ago, Nick Jones said: If you are happy with the way it drives, just enjoy it 🙂. This is the Newman cam spec, I'm just as you say going to enjoy driving it! Link to comment Share on other sites More sharing options...
Adrian Posted June 18, 2021 Report Share Posted June 18, 2021 Can I ask a daft question. As I am about to embark upon a 150 rebuild i was wanting to know why all the discussion about springs, damper oil and needles. As a standard carb, wouldn't a standard rebuild with normal components rectify any running issues or is it because of ported manifolds, exhausts, cams, etc altering original design principles? Adrian Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 18, 2021 Report Share Posted June 18, 2021 Ian is playing around his engine is not exactly standard but in normal trim the kit should have some of what you need to make a std run like a std . Pete Link to comment Share on other sites More sharing options...
Iain T Posted June 18, 2021 Author Report Share Posted June 18, 2021 Pete, you beat me I'm still having issues with the website. Adrian, yes it's because I and others more proficient than me have fiddled with the engine. Keep it standard and the carbs should remain as factory spec. Any head and cam modifications can make big differences to the air/fuel intake. Iain Link to comment Share on other sites More sharing options...
CVPwales Posted June 22, 2021 Report Share Posted June 22, 2021 Sorry to jump in and hijack the thread but you sound like you may be able to help me! My Vitesse 6 is as far as I know standard bar replacement carbs, previous owner apparently fitted rebuilt cdse 150 carbs but never got the tuning right, and boy is it rich, also can't balance them for love nor money. With all the messing about with the cdse carbs I have been considering getting a pair of cd150 3137f and r carbs and doing a rebuild using the 1600 needles available from J Paddocks, the jets are apparently the same for both 1600 and 2000. In your opinion is this a better solution than fighting with the cdse set up? Seems easier and with more flexibility to tune the older cd150 jets rather than the top needles on the cdse? Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 22, 2021 Report Share Posted June 22, 2021 there is no reason cdse wont run on a base CD carb engine apart from design changes the operation is the same you wont get 1600 needles for a biased needle CDSE carb thats the first snag 1600 on stromber CD150/150CDS used fixed needle 7B 2000mk2 has 150CDS/CDSE Biased needle B5CB the 1600 with CD /CDS has no air spring and has a heavier diaphragm holding top plate CD has thames barrier choke CDS has a staring valve choke on the fron carb CDSE may have a starting valve choke on both none of this matters unless the choke discs are badly corroded on a a CDSE set the needls so the delrin washer is level/flush with the base of the air piston take out the temperature compensators on the side and full cloase the small nut that holds the bi metal strip to fully shut the plunger make sure the two 0 rings that seal this gadjet are ok but ive not compared needle profiles but youre playing with something with no known base specified data on a 1600 you can s fit a fixed need air piston from a CD/CDS into the body of a CDSE/SEV and get the correct fixed needle but there is not means to centralise the very fixed jet in a CDSE body Pete Link to comment Share on other sites More sharing options...
CVPwales Posted June 22, 2021 Report Share Posted June 22, 2021 Thank you so much and that kind of confirms my suspicion that getting hold of a pair older cd150 carbs is the better option. Link to comment Share on other sites More sharing options...
Iain T Posted June 22, 2021 Author Report Share Posted June 22, 2021 1 hour ago, CVPwales said: Thank you so much and that kind of confirms my suspicion that getting hold of a pair older cd150 carbs is the better option. I have the CDS carbs (with the choke enrichment disc on the ftont carb and a joining hose to the rear) and it seems much simpler to adjust the jet at the bottom than mucking around with the needle in the CDSE. Also you can adjust the mixture while the engine is running. Iain Link to comment Share on other sites More sharing options...
Iain T Posted June 22, 2021 Author Report Share Posted June 22, 2021 1 hour ago, Pete Lewis said: 1600 on stromber CD150/150CDS used fixed needle 7B Pete, isn't the 7B needle a bit to tapered hence rich for a standard 1600? The 7Bs were too rich on my ported 2 litre. Iain Link to comment Share on other sites More sharing options...
CVPwales Posted June 22, 2021 Report Share Posted June 22, 2021 5 minutes ago, Iain T said: Pete, isn't the 7B needle a bit to tapered hence rich for a standard 1600? The 7Bs were too rich on my ported 2 litre. Iain Can't remember of the top of my head the needle number but there is a different one for the 1600 and 2ltr but the jet is the same. Will double check later but think your right and it's a 6? Link to comment Share on other sites More sharing options...
Iain T Posted June 22, 2021 Author Report Share Posted June 22, 2021 1 minute ago, CVPwales said: 1600 and 2ltr but the jet is the same. Yes as far as I know the jets are all 90 thou. Iain Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 22, 2021 Report Share Posted June 22, 2021 well Burlen quote 7B for 1600 getting the heavy piston top ring is the rocking horse pooh part guess a talk to Burlen a spring in a 1600 with std needles will be very rich (i tried that with the 6.3.1.) Pete Link to comment Share on other sites More sharing options...
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