VHPD Cam timing

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robin
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Re: VHPD Cam timing

Post by robin » Fri May 28, 2010 3:33 pm

Hi Kerry, is that comment from Dave online somewhere - I would be interested in reading the background to it - presumably when fitting the new pulley, the fitters didn't use the right timing slot for the cam dowel? Or what! The mind boggles ...

Cheers,
Robin
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roadboy
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Re: VHPD Cam timing

Post by roadboy » Fri May 28, 2010 8:09 pm

More of a case of terrible tolerances Robin.

In my experience. With the original 177 pulley fitted, most VHPD inlets were about 11 degrees away from optimal timing. With the 190 pulley fitted, which was supposed to fix this very problem, most inlets are about 5 to 6 degrees away from optimal timing. This is why you'll never get the best out of a VHPD without verniers.

Oh, and I usually go for .120" on the inlet and .100" on the exhaust. This gives good power but doesn't compromise the general driving manners.

Dan
SPS Automotive
Independent Lotus Specialists
http://www.spsautomotive.co.uk

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kerryxeg
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Re: VHPD Cam timing

Post by kerryxeg » Fri May 28, 2010 11:27 pm

Robin, I picked up Dave's comment from here

http://www.exiges.com/ubbz/ubbz/ubbthre ... 329&page=2

I guess the upgrade pulley must have had the correct markings, but they were ignored and the 177 settings were used. The manual I looked at didn't have any 190 numbers in it so you could see how that might happen.


I got an email from Dave this afternoon confirming the gaps he'd quoted are what he would use for 190 and I presume emerald. I did find a post stating the original settings which are significantly different .090 / .115 I think.

Thanks Dan your figures are in the range I'd been given so either would seem fine, how accurate can you really get this in practice I wonder. But, I wouldn't say the exige has exactly got good manners at the moment with the standard ECU etc.

Kerry

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robin
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Re: VHPD Cam timing

Post by robin » Sat May 29, 2010 12:08 am

Yes, the 190 pulley (which I've never seen) sounds like it has two slots cut - one being the original slot from the standard rover item, the other being a new slot cut in the adjusted position (which Dan points out is still not all the great). When you fit these pulleys it's important that you put the cam dowel into the new slot; if you leave it in the standard slot, you'll get standard cam timing.

Anyway, by all accounts verniers are needed to get this working well, so it's sort of academic ...

Cheers,
Robin
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kerryxeg
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Re: VHPD Cam timing

Post by kerryxeg » Wed Jun 16, 2010 11:46 pm

Cam timing and ECU, All fitted up today, superb, a very noticeable difference in torque.

Well Done Ricky.


Kerry

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