Valve timing GTA Atmo

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purches graeme

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Valve timing GTA Atmo

Postby purches graeme » Wed Jun 24, 2020 12:09 am

Hi all

have noticed that there appears to be a difference in the valve timing between the A and B banks on PVR Douvrin Atmo engines, i.e odd-fire.
The timing between banks on the even-fire offset-crank engines (GTA Turbo etc), appears to be identical.
I have found that the even-odd-fire cams are in fact identical, but the respective engines have different cam gears which is why the manual specifies different methods of setting the valve timing for the respective engines.
In my case, I have modified heads on my '90 D500, which were fitted by, or for, a former owner, and have now discovered that the gears on the cams were from an even-fire engine, and hence the timing cannot be set up in the usual manner.
I have had adjustable cam gears made by machining the toothed sprockets on the cams, and fitting an adjusting plate, and now just need to confirm the actual timing difference between banks.
On an English language Volvo spec sheet we have, it appears to be 2 degrees, but I have attempted to do a translation of a French Renault engine manual, and it looks to me from that to be more like 5%, but we are having some difficulty determining the exact setting.
Does anybody have an English engine manual they could copy the relevant bits from and email to me?
Thanks in anticipation!!

Graeme.
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Re: Valve timing GTA Atmo

Postby purches graeme » Wed Jun 24, 2020 1:48 am

Hi all
I have just scored a copy of the Delorean manual, which confirms that there is a 2 degree difference in valve timing between the two banks on the 2849cc engines.
So I think we are on the right track here now.
Keep you posted.
As a matter of interest, this is for my blue '90 car.
I sold the black '86 a week ahead of lockdown here, to a fellow who also owns a new Alpine, a Lotus Esprit, and a '72 Porsche 911.
I note there have been three GTA for sale in Aussie, one a pretty good looking project ATMO car in bits for round AU$27,500, and two runners, an ,87 Atmo for $27,500, and an 87 Turbo for $32,500. Both on Ebay AU.
I listed mine on line here for NZ$29500 (around $15,000 GB pounds), and sold it four hours later for the asking price to it good new home, effectively getting back close to what the car owed me.
The holdup has mostly been Covid lockdown and getting the adjustable timing sprockets machined, after discovering the problem outlined earlier.
Will update on the blue '90 when complete.
Cannot wait to get the car back!!!
Thanks to Martin and Stephen for their help along the way.
Cheers
Graeme


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