logicaluk
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Every days a school day round here
Posts: 1,373
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Jul 24, 2022 13:49:55 GMT
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I measured the valve lift on the Newman reground cam today Inlet 10.62mm Exhaust 9.93mm
I've put the feelers out for a damaged head for destructive testing. Dan
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Last Edit: Jul 24, 2022 14:22:09 GMT by logicaluk
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Darkspeed
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Club RR Member Number: 39
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The Flowbench thread.Darkspeed
@darkspeed
Club Retro Rides Member 39
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Jul 27, 2022 14:52:40 GMT
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That's a fair bit more lift that was anticipated - would have taken readings to 450. The graph can be extrapolated a little.
The outcome of the testing is that its not a bad flowing head for the valve sizes - being from Honda should we have expected anything less? - There is more to be had from it with the simple valve seat mods and with work on the valve and the seat angles there is probably a little to be gained at low and mid lifts as well.
The exhausts would also see some good increase in flow with a bit of work as they are more restricted than the inlets
The standard carbs are not what would be called a 34mm carb in the sense of a similar 1.25 (32mm) or 1.5 (38mm) SU/Stromberg - The 34mm in these carbs refers to the inner venturi diameter - like a 34mm choke in a 40 DCOE - they flow quite well as the drop in flow when on the head is pretty low - The manifold is also very well sized and is not a big restriction to flow to the head. It would benefit from some cleaning up of the castings and matching to the head but that's about it.
To get power from the engine it would lend itself to a turbo rather than N/A tuning - There is little point changing cams and carbs and going for 100 BHP N/A at 7000+ - that's what would be needed - as it will lose all of the drivability it currently has. The present cam would also probably suit a turbo quite well.
Careful working of the head as it is should give a 7% or so increase in power
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logicaluk
Posted a lot
Every days a school day round here
Posts: 1,373
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Jul 27, 2022 18:58:10 GMT
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Thanks DS, that is indeed food for thought.
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Darkspeed
Club Retro Rides Member
Posts: 4,878
Club RR Member Number: 39
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The Flowbench thread.Darkspeed
@darkspeed
Club Retro Rides Member 39
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12 months later..... The X-flow head from the Gemini is off getting fettled so I figured I would complete the fixture and try and run some numbers when I get it back. Sadly there will not be any before and after but who knows, in the future I may get hold of a stock head to test and complete any works I manage to do.
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Darkspeed
Club Retro Rides Member
Posts: 4,878
Club RR Member Number: 39
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The Flowbench thread.Darkspeed
@darkspeed
Club Retro Rides Member 39
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Moved the flow bench up to the garage - absolutely no space - so that I can run some numbers on the modified head. I forgot that building the mounting fixture is just part of the job, now I have to make the valve lifter fixture as well. Head looks a lot better than it did before Valve lift numbers for the Kent 234 are 10.74mm on the Inlet and 10.69 on the exhaust So if we divide those by 25.4 we have approx .420" so we will test to .450" lift in .050" increments The Mount for the mag clamp used for the Imp head works well enough on the XFlow.
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Darkspeed
Club Retro Rides Member
Posts: 4,878
Club RR Member Number: 39
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The Flowbench thread.Darkspeed
@darkspeed
Club Retro Rides Member 39
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Finished the lifting jig and rolled an inlet radius - jig will get a tidy up and a coat of paint before it gets put away. Now just need to find where the laptop has been stored.
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Darkspeed
Club Retro Rides Member
Posts: 4,878
Club RR Member Number: 39
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The Flowbench thread.Darkspeed
@darkspeed
Club Retro Rides Member 39
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Found the laptop and gave it an initial run to settle the bench - then went and found the DCOE-45 manifold its not a great port match off the shelf but its not bad either. Run the bench at a low-ish depression with the comparative flow at 28" And then opened 4 motors up to almost 28" to see if the flow velocity gained anything These readings are at max cam lift of 0.420 which was not the best flow ... The best flow figure was at .335 - after this flow dropped steadily until it stabilised at 0.380 and then remined the same even until the retainer hit the guide. later this week I shall run some proper tests after a full bench calibration and compensation run. It will not change the characteristics I have found but may alter the figures slightly
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Why do you think the flow peaked before full lift? Waisted valve stems getting into the unwasted part maybe? That's all I can think of, but I'm hardly an expert.
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Darkspeed
Club Retro Rides Member
Posts: 4,878
Club RR Member Number: 39
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The Flowbench thread.Darkspeed
@darkspeed
Club Retro Rides Member 39
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Why do you think the flow peaked before full lift? Waisted valve stems getting into the unwasted part maybe? That's all I can think of, but I'm hardly an expert. Valves are not waisted - The Ford GT valves are pretty cheap and nasty shape wise - This is after a fair bit of work - As this is budget upgrade it was £32 on valves rather than £160 This is what you start with I have read with the flat heads there can be a cylinder wall effect with flow being drawn onto the cylinder wall enhancing flow and then breaking away - I suspect that's why on the big valve full race heads they just straighten the port (cutting through the pushrod tube and sleeving afterwards) to direct more flow to the centre of the cylinder. When I get a bit more time I will remove the valve and do a bare port flow and take it from there. The peak flow number is still pretty healthy - What I will do however is grab this thing and run it on the bench as well. This is a full race chambered crossflow head. - I also have the matched 45 DCOE manifold that goes with that one as well. I may have some swanky valves in it as well which I may be able to test in the flat head. Ear defenders were the blue tooth headphones with a bit of Sharon Jones
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Last Edit: Oct 9, 2023 22:25:09 GMT by Darkspeed
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Darkspeed
Club Retro Rides Member
Posts: 4,878
Club RR Member Number: 39
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The Flowbench thread.Darkspeed
@darkspeed
Club Retro Rides Member 39
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Oct 28, 2023 17:54:43 GMT
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Had a play on the flowbench today today. Interesting comparison graphs of the Big Valve 1300 Chambered head and the ported 1600 head with the GT size valves - I will run another test that will compare the stock GT valve and the waisted stem "ground" valve that was used in this test. BV - In 41.3mm Ex 34.8 GT - In 39.25 EX 34.0 There will be some more work to see if its possible to prevent the drop off in flow we are seeing at max lift. It sounds like flow breaking away and going turbulent so it likely to be the SSR. Looking at the BV head the ports are far too small for the valve size.
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Darkspeed
Club Retro Rides Member
Posts: 4,878
Club RR Member Number: 39
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The Flowbench thread.Darkspeed
@darkspeed
Club Retro Rides Member 39
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Oct 28, 2023 18:06:18 GMT
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The chambered big valve looked very nice - But it has some issues, ignoring the lack of flow - the seats were inconsistent and on the exhaust side evidence of some serious leakage. The guides were also horrible and strangely longer than stock guides !
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Oct 28, 2023 18:48:24 GMT
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Small valve flow certainly looks positive! The lower lift being chunkier is probably worth more than the peak lift flow given it spends more time at that lift. Reckon you'll be able to improve the big valve with a bit of tidying?
Also, how much hp would you expect the big valve to make? Just out of curiosity.
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Darkspeed
Club Retro Rides Member
Posts: 4,878
Club RR Member Number: 39
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The Flowbench thread.Darkspeed
@darkspeed
Club Retro Rides Member 39
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Oct 28, 2023 19:23:58 GMT
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Small valve flow certainly looks positive! The lower lift being chunkier is probably worth more than the peak lift flow given it spends more time at that lift. Reckon you'll be able to improve the big valve with a bit of tidying? Also, how much hp would you expect the big valve to make? Just out of curiosity. The chambered BV head and engine is not mine - I do have the option of buying it and it does have some very nice parts as its all steel - My worry is that the work done on the valve seats is not good and the exhaust outlets have also seen some rather stupid grinding. GT BV As you can see by the flow figures this really adds nothing - but when an exhaust is mounted you are just asking for reversion. I may well take the exhaust ports on the GT out a little more but the flow figures are not too bad as is. Power wise the the BV head was in a race Caterham that was reportedly developing 150BHP (1380cc) I am doubting that figure although theoretically the peak numbers say it should support that sort of figure. Personally somewhere about 130 is more probable.
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Darkspeed
Club Retro Rides Member
Posts: 4,878
Club RR Member Number: 39
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The Flowbench thread.Darkspeed
@darkspeed
Club Retro Rides Member 39
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Oct 29, 2023 12:44:39 GMT
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I made an error during testing on the Exhausts yesterday - I forgot to flip the measuring plate. It reads low with the plate in the wrong way round. I also carried out a full calibration with the 100 200 and 300 CFM test plates, and made a couple of adjustments to get within 0.5% across all three plates. I then ran the tests on the "37" head. There is a little more to get from the exhausts but that's pretty good as is. Need to do some more testing and probing to see if I can recover the lost flow at the top end on the X-Flow.
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Last Edit: Oct 29, 2023 12:57:54 GMT by Darkspeed
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Darkspeed
Club Retro Rides Member
Posts: 4,878
Club RR Member Number: 39
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The Flowbench thread.Darkspeed
@darkspeed
Club Retro Rides Member 39
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Oct 29, 2023 16:33:55 GMT
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I took a flyer on it being SSR separation and took the grinder to that area to smooth the radius a bit more. I also dropped the standard valve back in as it was losing a lot of flow with that valve. The little bit of work on the SSR has certainly flattened the curve. I will drop the modified valve in and see what that does.
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Darkspeed
Club Retro Rides Member
Posts: 4,878
Club RR Member Number: 39
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The Flowbench thread.Darkspeed
@darkspeed
Club Retro Rides Member 39
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Oct 30, 2023 13:54:00 GMT
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Carried out more work in the area of the SSR then dropped the Modified and standard valve in to get a comparison Found the restriction. I doubt that there is much more to have - need to do some calculations before going at it any further. Next job is to have go at the exhaust - and first job on that will be to grind another valve shape as the standard valve is dreadful.
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Oct 31, 2023 10:08:09 GMT
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Nice work!
What makes you think you've found the restriction? Was it that the standard valve had levelled off and the modified valve kept going past it?
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Oct 31, 2023 13:26:12 GMT
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Can I show my ignorance and ask what the abreviation SSR means please?
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Oct 31, 2023 13:55:05 GMT
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Can I show my ignorance and ask what the abreviation SSR means please? That I do know! SSR is 'short side radius'. The inner radius of the curve the port makes as it drops down towards the valve seat. If it's too sharp then the air won't make the turn smoothly and your port loses flow.
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Oct 31, 2023 15:45:23 GMT
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Can I show my ignorance and ask what the abreviation SSR means please? That I do know! SSR is 'short side radius'. The inner radius of the curve the port makes as it drops down towards the valve seat. If it's too sharp then the air won't make the turn smoothly and your port loses flow. Thank you
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