P38A Mechanics, FIP and timing chain investigation

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tomcat59alan said:
Until they part company or jump a tooth.if the chains are stretched you can bet the sprockets are worn,:rolleyes: Your choice of course if it's still making a rattling after you've done the modulation.;) When I was in the trade I wouldn't touch the job unless everything necessary was replaced, they have a habit of coming back to bite you in the arse.:eek::D
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I cannot disagree with that, but with the modulation so far out and it being an easy fix, it's worth doing that first. I'm not suggesting the chains should be ignored. Don't forget the FIP was set like it is by a "professional mechanic":rolleyes:
 
Datatek said:
Idle should be 750 +/- 50 rpm so not too far out and may be affected by the modulation. Sort the modulation first then if needed look at the idle speed.
If the idle figure has been changed it's easy enough to correct it with Nanocom. By the way it is not always 128.
My method of setting the modulation is not as you put it "a bodge", it's a very accurate way of getting it right which is almost impossible using the DTI method.
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I have used the same method myself in the past but both you and I started from a known starting point. I have no idea where he's starting from, only that wherever it is it isn't right. I'd put everything back to spec and then look for what isn't right. Once idling right he can then tap the pinp towards the engine until modulation comes down to 50%.
 
Grrrrrr said:
I have used the same method myself in the past but both you and I started from a known starting point. I have no idea where he's starting from, only that wherever it is it isn't right. I'd put everything back to spec and then look for what isn't right. Once idling right he can then tap the pinp towards the engine until modulation comes down to 50%.
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I suppose I could do that as well if my modulation is out,I'll check when the weather improves,, didn't have the Nanocom when I changed my chains, guides and sprockets.;)
 
Grrrrrr said:
I have used the same method myself in the past but both you and I started from a known starting point. I have no idea where he's starting from, only that wherever it is it isn't right. I'd put everything back to spec and then look for what isn't right. Once idling right he can then tap the pinp towards the engine until modulation comes down to 50%.
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Since the modulation being way out can affect idling I disagree with you. The OP is starting from a known point, the engine runs and the modulation is 93%, thus it is easy to calculate how far to move the FIP rather using your hit and miss guesswork method. In any case the idle figure is only 20rpm above the maximum figure so is not likely to make a big difference.
 
Datatek said:
Since the modulation being way out can affect idling I disagree with you. The OP is starting from a known point, the engine runs and the modulation is 93%, thus it is easy to calculate how far to move the FIP rather using your hit and miss guesswork method. In any case the idle figure is only 20rpm above the maximum figure so is not likely to make a big difference.
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Not being funny Keith but how can one evaluate your method if you won't disclose it?
 
tomcat59alan said:
Not being funny Keith but how can one evaluate your method if you won't disclose it?
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I marked up the pump, drew a guage with a Sharpie on the bit behind and then slackened the pump and tapped it ever so gently toward the engine until the modulation went to 50%. Did it with a dial guage when I replaced the FIP though.
 
Grrrrrr said:
I marked up the pump, drew a guage with a Sharpie on the bit behind and then slackened the pump and tapped it ever so gently toward the engine until the modulation went to 50%. Did it with a dial guage when I replaced the FIP though.
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So after doing the timing with the DTI have you checked it with Nanocom?
 
tomcat59alan said:
Read my post I said One not Me, if your method is so good don't hide your light under a bushel.spread the word.:rolleyes:
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I gave up posting many things as despite fact and figures a certain Mr Walmsley always saw fit to rubbish everything.
The information is available to almost anyone that wants it without having to go to the trouble of searching the archive.
 
Datatek said:
I gave up posting many things as despite fact and figures a certain Mr Walmsley always saw fit to rubbish everything.
The information is available to almost anyone that wants it without having to go to the trouble of searching the archive.
Click to expand...
Well Wammers isn't here anymore to comment but perhaps he saw something in your method that didn't sit well with him.
 
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