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Cam Timing

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#1 minip

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Posted 16 July 2018 - 07:27 PM

So looking for some help.  Rebuilt my engine with Kent 276 Cam.  To time cam I used a Dti to find true TDC on No1 piston.  I set the timing, again using a Dti and No 1 inlet using the push rod with the Dti taking a reading from the push rod.  The inlet timing figure from Kent is 106 deg and I managed to get it adjusted to 105 deg.

 

I used adjustable timing gears and duplex chain

 

Once i had fitted the new timing cover and turned the engine to TDC the crank pulley timing notch is about 2 inches short of the timing pointers on the cover.  When i line up the crank pulley with the TDC pointer, No 1 piston is half way down the cylinder.

 

Anyone got any idea what if this is right?  Also could it be the timing cover that is wrong?

 



#2 Chris.Williams

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Posted 16 July 2018 - 07:34 PM

So the key way on the crank is pointing at 12 o'clock and your piston is halfway down the bore?
Is this what you're saying?
Or are you lining up the key way with the timing cover notches?

#3 DeadSquare

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Posted 16 July 2018 - 07:53 PM

MY  RANT :

 

Selling people expensive adjustable timing sprockets that are really only needed when trying to extract the last 1/2 BHP from an engine, is taking advantage of them.

 

The standard duplex chain and sprockets are just fine for a fast road cam.  (And the timing marks are fairly simple to line up)



#4 minip

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Posted 16 July 2018 - 08:27 PM

Chris,  so the crank pulley is on and the timing notch is at 9 o clock the timing cover TDC pointer is at 11 o clock.  

 

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#5 mini13

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Posted 16 July 2018 - 08:37 PM

I've seen cams way off from the figures when lined up, iirc the worst was a vp8 that was 8 degrees out, I always dial them in.

#6 mini13

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Posted 16 July 2018 - 08:39 PM

As for the timing marks not lining up at Tdc, what does the damper rubber look like? If the dampers shot to outer could have moved

#7 minip

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Posted 16 July 2018 - 08:42 PM

mini 13, that makes sense i'll have a look at the damper.  cheers,



#8 GraemeC

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Posted 16 July 2018 - 08:43 PM

Probably not a Mini bottom pulley - I have one some where the same, might be off a spridget

Edited by GraemeC, 16 July 2018 - 08:43 PM.


#9 minip

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Posted 16 July 2018 - 08:50 PM

How do you tell the difference?  



#10 GraemeC

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Posted 16 July 2018 - 08:56 PM

Whether the notch lines up or not!

#11 Steve220

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Posted 16 July 2018 - 09:01 PM

Which pushrod hole for cylinder 1 did you use?

#12 Spider

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Posted 17 July 2018 - 06:21 AM

It looks to me you have a failed Harmonic Damper. Don't use it and replace it before driving the car.



#13 minip

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Posted 17 July 2018 - 07:40 AM

Steve, i used the second pushrod hole in from the thermostat housing end of the engine.



#14 Cooperman

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Posted 17 July 2018 - 09:16 AM

I once had an aftermarket cam and aftermarket sprockets which resulted in the cam being 9 degrees retarded when the trial-build was done on the dot-to-dot basis. I switched to a vernier set to correct that as it was a bit too much for an offset key.
Even on a road car 9 degs would have resulted in poor performance and probably higher fuel consumption.

#15 minip

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Posted 17 July 2018 - 05:22 PM

I have checked the damper again, it definitely looks like it is past its best.  There is no rubber showing at all so I think the damper may well be the issue.  

 

When I first checked the timing with the dot to dot it was 9 deg out, having the vernier gears made timing the cam in simple.

 

Anyone got a 1275 A+ damper for sale?







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