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Discussion Starter #1
Ciao a tutti, ho una gamma rgover classic con 3.9 v8 ricostruita con una kent cam h 180 ... nuovo motore passo-passo oem e non ho perdite d'aria nella camera del plenum, manometro rover non ha codice difetto, il mio problema è nel cambio di marcia , quando stacco la frizione con poco gas il motore accellera giri al minuto 1200-1500, oppure fermandomi ad un incrocio prima di scendere ai 700 giri/min impiega circa 3 secondi
Hi everyone, I have a range rgover classic with 3.9 v8 rebuilt with a kent cam h 180 ... new oem stepper motor and I have no air leaks in the plenum chamber, rover pressure gauge has no fault code, my problem is in the gear shift, when the clutch is released with little gas the engine accelerates revolutions per minute 1200-1500, or stopping at an intersection before descending to 700 rpm takes about 3 seconds. I have setting the idle but i have a small difference... i have setting high timing ignotion 19° i think is the causes.... whow do you think?
 

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Mine has std cam but runs fine on timing at 6 to 8 degree.

Did you just change the camshaft or have the pistons and rings been replaced?

If you take off the oil filler cap when it's running is it blowing out air from there? And when you open the cap, does the engine slow down?

Do you have any compression test numbers to assess the bore condition?

If you rev it with a strobe connected does the ignition timing go back down to base setting immediately after the revs drop?
 

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Discussion Starter #6
Pistons, piston rings, cylinders, double chains, bearings, they are all new, the engine has just been rebuilt ...
opening the oil cap the engine rpm drops and does not blow ...
the compression is good and homogeneous but I don't have or written data ...
I never did the timing test you suggested
 

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If the revs drop when you remove the oil cap it suggests that the crankcase is being pressurised, this can push air (not measured by the mass airflow meter) into the intake.

This acts like an air leak and runs the engine lean which speeds it up with cap closed. You can run it gently without oil cap on to see if the tickover works like this just as a test.

You need to get a compression check to see the status as leaking past the top piston ring will pressurise the crankcase. They will need some miles from being rebored to work correctly but a test will let you see what is happening.
 

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Discussion Starter #8
Thanks for your suggestions ... I have another question, why the idle is high when I use little gas, and instead if I pull the gears the rpm drop immediately to normal idle?
 

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I didn't quite understand your sentence "when I pull the gears" do you mean with clutch pushed down so not driven transmission?
 

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Discussion Starter #10
sorry for my english, i meant full throttle and change gears at 4000 rpm during the shifting gear when the clutch is lowered, the number of engine revolutions drops quickly to reach 1100 rpm once is stopped, idle returns to 700 rpm. this not happens when I advance with little throttle or during gear changes even if I do them at 1000 rpm when the clutch is lowered the minimum will go up to around 1500 rpm
 

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Sounds to me you might have some binding in your linkage. I presume the idle returns to normal if you 'snap the throttle', while it stays high is you open it only a little and gently bring it back. The throttle plate might not close correctly because something is binding.

Often these issues are a result of general tuning and many small things adding up like vacuum leaks etc.

Also shifting at 4000 rpm sound like you are driving this old car hard.
 
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