rslandys3 Posted June 12, 2007 Author Share Posted June 12, 2007 Have you checked the compression? (compression tester?) I will try to get hold of one and check it but the idle is pretty smooth so I'd guess its ok? Quote Link to comment Share on other sites More sharing options...
edwardatherton Posted June 13, 2007 Share Posted June 13, 2007 Have you checked the accelerator pump in the carb? Quote Link to comment Share on other sites More sharing options...
rslandys3 Posted June 13, 2007 Author Share Posted June 13, 2007 Have you checked the accelerator pump in the carb? It's a brand new carb so I doubt it but will check. Quote Link to comment Share on other sites More sharing options...
rslandys3 Posted June 16, 2007 Author Share Posted June 16, 2007 compression was way out. 8,8,10.8,11.8. (bar) I suspect its the valves as the were a little pitted. Will re grind and then try. Quote Link to comment Share on other sites More sharing options...
hattymender Posted June 23, 2007 Share Posted June 23, 2007 Encouraged by the fact that there are others out there daft enough to muck about with a perfectly good, if incontinent, engine I went for it and had .080" skimmed (Hatty's a 2.5 so .080" should be enough). Wednesday morning we picked up the head complete with re-ground valves and seats. The valves had cleaned up beautifully, wife and daughters slightly disturbed by sight of middle aged man drooling over box full of valves. After limbering up with a couple of fags and a bout of coughing brother in-law and self got started on the rebuild. He won the 'how far can you fire a collet?' competition. He also won the swearing competition. Point of note. Rocker shaft. Very, very annoying if you forget to align the peg hole before torquing down the bolts and setting valves. We left the timing standard. Not had chance to go very far yet but she does seem much the same at low throttle and some modest improvement (nothing startling) when you put your foot down. Which is pretty much in line with expectations. I have a nagging feeling that just re-grinding the valves may have given much of the improvement. The doubt reinforced by the fact that when I looked at the bill the valve re-grind was £28+VAT whereas the skim was £80+VAT. But it did look nice. Quote Link to comment Share on other sites More sharing options...
Gareth Dickens Posted June 24, 2007 Share Posted June 24, 2007 Shoul have remarkable improvement. Adjust timing. Did you recheck the compression? Did you adjust the valve clearances? Quote Link to comment Share on other sites More sharing options...
rslandys3 Posted June 24, 2007 Author Share Posted June 24, 2007 Encouraged by the fact that there are others out there daft enough to muck about with a perfectly good, if incontinent, engine I went for it and had .080" skimmed (Hatty's a 2.5 so .080" should be enough). Wednesday morning we picked up the head complete with re-ground valves and seats. The valves had cleaned up beautifully, wife and daughters slightly disturbed by sight of middle aged man drooling over box full of valves. After limbering up with a couple of fags and a bout of coughing brother in-law and self got started on the rebuild. He won the 'how far can you fire a collet?' competition. He also won the swearing competition. Point of note. Rocker shaft. Very, very annoying if you forget to align the peg hole before torquing down the bolts and setting valves. We left the timing standard. Not had chance to go very far yet but she does seem much the same at low throttle and some modest improvement (nothing startling) when you put your foot down. Which is pretty much in line with expectations. I have a nagging feeling that just re-grinding the valves may have given much of the improvement. The doubt reinforced by the fact that when I looked at the bill the valve re-grind was £28+VAT whereas the skim was £80+VAT. But it did look nice. Good to hear it works. I seem to be in trouble with mine, used a cheap copper head gasket which lasted all of ten minutes. Fitted (+grinded) new valves to my head and did the machining myself at my university workshop so all in all its cost me about 25 quid. Do you have any idea what the compression is now? Mine is about 9.5 but its a 2.25. I think standard timing should be fine too, fuel round here seems to be 95oct ish. I will install water injection if it starts knocking. The power/compression curve flattens off pretty rapidly after about 9.5 to 1 so thats where I left it. You could probably get away with leaning out the carb a little too. Quote Link to comment Share on other sites More sharing options...
hattymender Posted June 24, 2007 Share Posted June 24, 2007 Good to hear it works. I seem to be in trouble with mine, used a cheap copper head gasket which lasted all of ten minutes. Fitted (+grinded) new valves to my head and did the machining myself at my university workshop so all in all its cost me about 25 quid. Do you have any idea what the compression is now? Mine is about 9.5 but its a 2.25. I think standard timing should be fine too, fuel round here seems to be 95oct ish. I will install water injection if it starts knocking. The power/compression curve flattens off pretty rapidly after about 9.5 to 1 so thats where I left it. You could probably get away with leaning out the carb a little too. Have lost the sums but should be 9:1 or near enough. To be honest I haven't tried it on pertrol as 99.9% of my running is on LPG. Did a longer run today and things are much better at higher (well, relatively higher) speeds. I can now keep speed up into wind uphill. I should have been a bit more scientific and timed my 40-60mph before and after. Should be interesting to do a fuel consumption comparison. I'm painfully aware of the 'before' figure for that one. Quote Link to comment Share on other sites More sharing options...
rslandys3 Posted June 25, 2007 Author Share Posted June 25, 2007 Have lost the sums but should be 9:1 or near enough. To be honest I haven't tried it on pertrol as 99.9% of my running is on LPG. Did a longer run today and things are much better at higher (well, relatively higher) speeds. I can now keep speed up into wind uphill. I should have been a bit more scientific and timed my 40-60mph before and after. Should be interesting to do a fuel consumption comparison. I'm painfully aware of the 'before' figure for that one. Running on lpg the timing should be advanced a bit but be careful as it may knock on petrol with the higher compression. Quote Link to comment Share on other sites More sharing options...
hattymender Posted July 21, 2007 Share Posted July 21, 2007 Running on lpg the timing should be advanced a bit but be careful as it may knock on petrol with the higher compression. Just a quick follow up. After 1500 miles since skimming head I'm averaging 17.5mpg on LPG from the previous 16mpg. Not done enough on petrol to make meaningful measurement. Performance is a bit more subjective but it's 'better', pulled 2.5 tons today without embarrassment. I was worried that I'd loose some tractability from low revs but if anything it's improved and smoother. As an aside benefit replacing the stem seals has improved oil consumption. Was it worth it? At the time I was doubtful but a month after all the agro (and bill) the pain has dimmed and I'm pleased I did it. rslandys3; Did you get running? Quote Link to comment Share on other sites More sharing options...
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