Darkspeed
Club Retro Rides Member
Posts: 4,878
Club RR Member Number: 39
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83 Triumph Acclaim SprintDarkspeed
@darkspeed
Club Retro Rides Member 39
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The GW is 6 x 250 CC - and yes very similar architecture
Your sanding work in the ports would not have changed very much
Both engines have been specifically designed to produce torque and produce it efficiently over as wide a RPM spread as possible.
To get more power - the head needs to be ported properly - the cam needs to be timed in correctly - you need bigger carbs - a nice tubular 4-2-1 would not hurt.
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Last Edit: Jun 1, 2022 12:05:11 GMT by Darkspeed
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logicaluk
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May 19, 2022 20:32:00 GMT
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I think for now I will have to live with it as is, as is.
A better job of porting would be sensible.
And a propper job of cam timing also sensible.
Bigger carbs I would prefer injection, refitting the original one to see if it is flawed, then build a better less compromised version.
The exhaust manifold will depend on the outcome of the above, if enough gains can be found then yes, but I not want to put money in to a manifold if not as it would want to turbo it.
Andrew, thank you.
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May 20, 2022 12:27:05 GMT
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I suppose with injection you could use the same manifold for NA or a turbo application so that would be a step forward whichever option you choose. If you can get a wideband in there then you might be able to get some info about whether the changes you're making are improving things or not. It's not quite a rolling road, but by and large if the AFR changes for the leaner on a MAP or alpha-n setup then you're getting more air into your cylinders/better combustion in that rev range. I've chucked the specs for an EN4 into my little engine internals spreadsheet and it's coming out at 20.5m/s mean piston speed at 7500rpm which is respectable but likely attainable. If it'll breathe that high up then you should be able to make decent power. Was that rolling road picture with the standard cams or Newman ones? Darkspeed do you know if you can see valve float in a corrected dyno chart? I know you can on the uncorrected ones as the power starts to get really choppy. |
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Darkspeed
Club Retro Rides Member
Posts: 4,878
Club RR Member Number: 39
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83 Triumph Acclaim SprintDarkspeed
@darkspeed
Club Retro Rides Member 39
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May 20, 2022 15:35:18 GMT
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As far as I know it's the same as any issue with cylinder filling - power production stops - depends how bad it is.
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logicaluk
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May 23, 2022 20:22:16 GMT
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I suppose with injection you could use the same manifold for NA or a turbo application so that would be a step forward whichever option you choose. If you can get a wideband in there then you might be able to get some info about whether the changes you're making are improving things or not. It's not quite a rolling road, but by and large if the AFR changes for the leaner on a MAP or alpha-n setup then you're getting more air into your cylinders/better combustion in that rev range. I've chucked the specs for an EN4 into my little engine internals spreadsheet and it's coming out at 20.5m/s mean piston speed at 7500rpm which is respectable but likely attainable. If it'll breathe that high up then you should be able to make decent power. Was that rolling road picture with the standard cams or Newman ones? Darkspeed do you know if you can see valve float in a corrected dyno chart? I know you can on the uncorrected ones as the power starts to get really choppy. I have a wideband, IIRC the dyno run was on the Newman cam, set up on the timing marks, not in the normal acclaim set up position which is half a tooth out. |
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logicaluk
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May 23, 2022 20:42:32 GMT
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This weekend has been very disappointing, frank towed my tiny caravan up into the North Yorkshire Moors, he wasn't happy, I think there was some detonation, if I had taken my laptop I could have at least tried a different ignition map, but I wouldn't be surprised if I've done some damage to the engine, oil pressure seems OK. I'll have to go over it one evening, I had to get back as I had a job interview, which I got and should put me on a far better financial keel, and some actual money for this project.
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Last Edit: May 23, 2022 21:38:56 GMT by logicaluk
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May 24, 2022 11:56:51 GMT
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Hum, so maybe the fuelling wasn't what it should be so a combination of high load and a smidge more altitude made it run lean? Hopefully no damage!
Congrats on the job though! Exciting to have a bit of extra cash around to play about with things.
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logicaluk
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May 31, 2022 21:29:03 GMT
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Probably going to make my self look daft, but When I say detonation, I heard what I can only describe as a jangling noise in (I assume) the exhaust. I don't recall the AFR going leaner than 16.
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Last Edit: May 31, 2022 21:30:29 GMT by logicaluk
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logicaluk
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Good news, compression test shows 200psi across the board, plugs look like this     I'm running BP6ES's as instead of the stock BP5ES with a 0.8mm plug gap All sounded well on a drive, and much better after an oil change, couldn't make it detonate even going 50-70mph in 5th. I even remembered to take the laptop and got a data log, if anyone wants to see it, message me and ill email it. |
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Last Edit: Jun 3, 2022 15:25:59 GMT by logicaluk
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logicaluk
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Yesterday I managed to get it to make the noise, and notice it went very lean 17.3 was the worse I saw, which is odd seeing as every where else it's numbers are pretty much perfect, idles around 14.7 and 12 ish on power, more information required.
A run out with data logging will help.
Dan
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Very interesting. What were you doing when it went lean?
Personally I've never really heard detonation before, but 'jangling noise' fits what other people have described.
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logicaluk
Posted a lot
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Very interesting. What were you doing when it went lean? Personally I've never really heard detonation before, but 'jangling noise' fits what other people have described. IIRC Under load, driving up a slight hill at partial throttle can't remember how many RPMS but I think it would have been mid band 3.5k ish. |
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logicaluk
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Hopefully typing this out, will help it make sense.
I took the carbs off to test a known good set on a mates car, worked fine.
Fitting the original ones off his car to check them, (he had swapped them out for a spare set) they would barely run.
Whilst getting ready to fit them I saw a spark in the engine bay and the smell of ozone, and the main fuse Wendy away, strange thing is I can't figure out what would be live there with the ignition off, afterwards everything seemed fine, fired up, drove 1 car length and stopped this time taking out the microsquirt fuse, unplugged everything connected to the microsquirt loom and it still blew the fuse, unplugged the microsquirt from the loom and it's ok, so it's not in the feed side. I'll have to go over it with a multimeter tonight.
Dan
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Jun 16, 2022 10:29:33 GMT
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Hum. Not sure on the layout of these cars, but the main things I can think of that would be always live are the big battery positive cable that goes to the starter and alternator. Anything touching those? Although those wouldn't be fused...
Do you have a multimeter and a wiring diagram?
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75swb
Beta Tester
Posts: 1,052
Club RR Member Number: 181
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83 Triumph Acclaim Sprint75swb
@75swb
Club Retro Rides Member 181
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Jun 16, 2022 11:08:44 GMT
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No ideas on the spark and the fuses, but I'd always recommend a check of the fuel pumps/lines/filters just in case something simple is slowing supply going up hill under load from the supply side.
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logicaluk
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Jul 10, 2022 20:57:57 GMT
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There's nothing like a spot of motor sport to get the mojo going, thanks to frank driving like a sack, I spent a very pleasant day navigating in an early MK1 MX5, doing the Caves Classic Run a 4 hour 70 mile navigation event with tulip maps timed at 24mph, in which we came 3rd with an average speed of 24.3 mph. It was bloody good fun.
When I got home, I went to see Frank.
When the Micro Squirt popped its fuses (I've still not got a definitive test on that), I fitted a dizzy with a Lucas vac advance unit bodged on fitted, the reason for this its the one part that's made of 100% pure unadulterated unobtainium, I can't remember when I last saw a good manual spec one, so I had a go at making a Lucas one work.
I've got a good triomatic vac advance unit, but the curve is somewhat different and from what I recall the trio ones don't drive as well as the manual ones.
Vac advance
Manual vac advance starts at 120 mmHg and finishes 13-17 degs at 225 mmHg
Trio vac advance starts at 200 mmHg and finishes 4-8 deg at 275 mmHg
base timing vac connected
manual 5 deg
trio 12 deg
I've also found a 1984 Honda prelude advance unit for sale, but I don't know the spec.
Typing this has jogged my memory, now I'm pretty sure it doesn't go in on the stock set up marks, oops,
Ill have another go at re-timing it one evening.
dan
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Last Edit: Jul 10, 2022 21:06:24 GMT by logicaluk
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logicaluk
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Jul 11, 2022 18:49:24 GMT
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Later this month, I am taking a trip to visit Darkspeed and his flow bench, to see how well the acclaim head flows, and see if there is a flaw in the setup. The first thing to do was build a valve lifting jig, the acclaim has a 34 deg roof, the jig will bolt to the camshaft fixings and needs to have a 17 deg angle, I have to confess I didn't use CAD instead I went straight to steel, and made this.   Today I cleaned up the head starting with the valves, all the bases, springs, retainers and collets had a bath in some stale petrol in a container in the sonic cleaner. I started by jet washing the head and spraying it with degreaser, a neighbour walked by and asked what it was from then offered to take it to work tonight and put it in the tank at work. We will see how it looks tomorrow. The valves were brushed up, on the bench wire wheel.  And they cleaned up nicely. But my phone battery died, so I can't prove it today. |
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Last Edit: Jul 11, 2022 18:54:52 GMT by logicaluk
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logicaluk
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Jul 14, 2022 18:57:07 GMT
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today I recived the cylinder head back, I couldnt be happier.   and the valves and springs   1 step closer, next I need to dig out, manifolds, carbs and the old throttle body setup Dan |
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"1 step closer, next I need to dig out, manifolds, carbs and the old throttle body setup Dan" ...and don't forget the many happy hours grinding/lapping the valves back in !  |
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logicaluk
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Jul 15, 2022 15:13:50 GMT
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I usually cheat and get 3 angle valves cut, which don't need lapping in.
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