Magnesium 2.9L Engine - Any Advice

[Silver72_2.9L]

Hi all

Firstly to introduce myself: I have just joined this forum having bought my dream 911 to restore. I’ve had an SC and 912 previously but recently found a 1972 911T in rhd, which are rare in the U.K. I’ve always read a lot on this forum as there are some amazingly knowledgable posts on here. Hopefully one day I can add some value rather than just ask questions.

So the car I bought has been used for racing and the 2.4 engine was upgraded to 2.7 and then again from 2.7 to 2.9 with a number of RSR parts, like the camshafts. It was done by the talented Bob Watson Engineering in the U.K and his last dyno had the car at 250hp. However I believe the case is a magnesium (911/57 case with no ribs) and that it’s often advised to not push over the 2.7L builds. I wondered if anyone had any thoughts on what they might do with the engine to ensure it’s not a ticking time bomb, and help improve reliability. Its a number matching car and I don’t want to be the one to damage the engine.It’s used frequently and will continue to do so.

Any thoughts or advice on what to do to it, to get the most out of it and help reliability, would be greatly appreciated.

[geneulm]

Twin plugs!

Back off the cams to ge60 or similar.

As much cooling as you can get.

[raspy2point2]

Early into my driving with other Porsches, I noticed a good number of 911's having problems with points not working right. So I changed mine to Pertronics and never had a problem for over 20 years of driving with Pertronics installed on my dizzy. Chris

[Silver72_2.9L]

Thank you both. Good ideas. Twin plugs in the U.K. seem even more pricey than get one in the US, so might need to see how I can find a sensibly priced option.

Any other thoughts greatly appreciated.

[Bobboloo]

I will echo what geneulm said about heat. Heat is a killer of all engines and the magnesium cased engines are more vulnerable. I would start by blocking off the open heater ducts. Your loosing cooling that could be usedto help keep the temps down.Also put an air filter in the airbox. Dirt is getting sucked into the engine wearing out all your parts. Make sure you have an accurate temp gauge. You can verify your gauge with an infared reader. It's highly likely that you don't have a fan on your front oil cooler. (asuming you have one) Race cars don't need the fan on the front cooler obviously but if your driving in traffic on a hot day you might need it. They are cheap. MFI engines in general don't run hot because of the richness of the fuel mixture. If yours is running hot then check the air to fuel ratio to make sure you're not lean in any RPM ranges.

[Bobboloo]

Also twin plugs won't lower temps. It will just help prevent detonation. High compression engines like yours generate more heat and are prone to detonation. High octane fuel is probably necessary since you have a single plug setup. By the highest octane you can.

[Saskia]

If you have not joined DDK-online in the UK yet then you should. Another group of knowledgeable enthusiasts.