Ken, putting the reason for larger clearances aside , would it not actually be a bit quicker on the pick up with tighter valve clearances ,higher lift?
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| Author: | J-dub [ May 28th, 2011, 4:53 pm ] |
| Post subject: | a tappy tappet is a happy tappet.. |
Just wondering At what point is a Tappet to tappy? Reason I ask, is the valve clearences where completly shut when I just did the service, no gap at all. I've now set them at 0.20mm(no arguments) and there very tappy the engine sounds different. Just wondering where you draw the line, its definatly not knocking,but tapping.. |
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| Author: | Russell [ May 28th, 2011, 5:38 pm ] |
| Post subject: | Re: a tappy tappet is a happy tappet.. |
What are you expecting as an answer? A dB reading? I don't think without hearing it or you hearing various different cars that are varying degrees of acceptability you're going to get an answer that'll help. Maybe you're just a bit more aware of the noise now you've spent the morning listening to it? |
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| Author: | 2CViking [ May 28th, 2011, 6:22 pm ] |
| Post subject: | Re: a tappy tappet is a happy tappet.. |
This may very well turn in to an argument but my opinion is that 0,20 mm is what Citroën set them to. I’ve done this since 1978 and never set any valves at 0,25 mm as the pomes recommend. Noisy valves are normally a sign of ware and that you can’t do much about. Not that it matters much however I’ve seen some 2cv where the valve stem (exhaust valve) was cooked causing the gap to change rather quickly due to the stem expanding and shrinking after a relatively short time. Also be aware of other noises like cam followers, crank shaft small and big end etc. either combined or separately. Maybe get someone familiar with 2cv engines to listen before jumping to conclusions. |
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| Author: | ben [ May 28th, 2011, 6:58 pm ] |
| Post subject: | Re: a tappy tappet is a happy tappet.. |
Mine's very tappy after set at 0.2 inlet and 0.25 exhaust as advised,or at least sounds like it to me after adjustment. I can see the logic in it too , citroen may have recommended 0.2 in 1970-ish but petrol is very different nowadays, burns leaner and hotter. |
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| Author: | ken [ May 28th, 2011, 7:48 pm ] |
| Post subject: | Re: a tappy tappet is a happy tappet.. |
James, a couple of questions. 1/ Do you know how many miles it's done without the valve clearances being checked? 2/ Does it run any better, now that it's got valve clearances? Things such as better pickup and a steadier tickover... ken. Jameswallace wrote: Just wondering At what point is a Tappet to tappy? Reason I ask, is the valve clearences where completly shut when I just did the service, no gap at all. I've now set them at 0.20mm(no arguments) and there very tappy the engine sounds different. Just wondering where you draw the line, its definatly not knocking,but tapping.. |
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| Author: | ben [ May 28th, 2011, 9:59 pm ] |
| Post subject: | Re: a tappy tappet is a happy tappet.. |
Ken, putting the reason for larger clearances aside , would it not actually be a bit quicker on the pick up with tighter valve clearances ,higher lift?
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| Author: | twofifty AZU [ May 28th, 2011, 10:04 pm ] |
| Post subject: | Re: a tappy tappet is a happy tappet.. |
Are you sure you've done it correctly? It seems highly improbable that you stated with an engine that ran but none of the tappets had any clearance at all.... |
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| Author: | ken [ May 29th, 2011, 1:49 am ] |
| Post subject: | Re: a tappy tappet is a happy tappet.. |
Ben, a standard A series camshaft has 6.24mm lift, so in theory using 0.25mm clearance for the valves instead of 0.2mm might possibly make a difference, but it's always going to be less than 1%...  In practice, another effect comes into play, which is that the slightly earlier closing of the inlet valve on the compression stroke produces a higher cylinder pressure and improves bottom end torque. I'd rather opt for improved low end torque and acceleration than a tiny gain in flat out performance any day... Of course, there's also much less chance of a burnt valve, which is a serious risk if valve clearances are too tight or if regular checks are neglected. ken ben wrote: Ken, putting the reason for larger clearances aside , would it not actually be a bit quicker on the pick up with tighter valve clearances ,higher lift? |
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| Author: | J-dub [ May 29th, 2011, 11:44 am ] |
| Post subject: | Re: a tappy tappet is a happy tappet.. |
Right it seems faster. I last did the clearances about 11 months ago Before then no sea It seems to run better and have more power (or just acceleration) |
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