Awesome. I'll take the A. In regard to the articles, the first was very high level and subjective while the second was an academic article based on fact, which I enjoyed reading. Has Porsche ever published the exact alloy compound used in our 964 chain boxes along with any coatings used for corrosion/temperature resistance? That might be fodder for more holiday reading.

While not aligned in profession with you guys, my professional career is 25+ years in data. I'd love to map a chart or three on the aluminum and magnesium alloys used in the two chain boxes in question here combined with academic research to see at what point one would be more beneficial over the other in terms of resistances and other variables. May just prove your points @cobalt ....which, naturally would warrant an afternoon in the passenger seat of your 3.6T.

 

Fascinating stuff! In regards to exact alloy composition, may I suggest that if someone has their 964 apart, they could bring the chain box and or cover to a university that teaches mechanical engineering. Their metallurgy labs should have non-destructive test equipment that can identify the exact composition of the material and match it to known alloys. They would likely do this at no charge especially if you arrive with coffee and donuts.

 

So long as the salt is off the road I am always willing to give rides in the turbo. I did not see the second article until just now. Looks like typical days reading back when I did this for a living. I do miss it but retirement is good and allows me to work on these daily. I much prefer doing it as a hobby than being paid. I can really get into the projects that way and not worry if I am making book time. LOL

I am not familiar with the Journal of Materials science but there are so many institutions. I dealt primarily with AMS, ASTM, MIL, and a few others. You might look into MIL (AMS) M-3171 it covers the DOW conversion treatments my grandfather helped design back in the 30's. My grandfathers research is usually part of many of these articles but he doesn't get any credit. I have his hand written journals from the 30's to the 50's and he tested every type of alloy and coating for magnesium and aluminum. He turned over all of his R&D to the federal government in 1940's which helped reduce the national scrap rate by 40% for both aluminum and magnesium. I have a letter to him from Igor Sikorsky, DOW and the federal government stating that it is possible he helped save the country from losing WWII as his R&D helped to build aeroplanes, boats etc that if he didn't help reduce scrap would have lead to a shortage of weaponry. Ironically in the 50's after he retired many took his notes and added to them taking full credit for his efforts. I plan to one day turn everything over to the American Foundrymen's society. I am sure it will make for interesting controversy over who discovered what.

I have a lab that did all my spectrochemical analysis and would be easy enough to have tested. Every part I made had to be tested for ultimate tensile, hardness and chemical composition at a min. Even the raw material had to be tested prior to casting parts and checked against the smelters report. There were times I had to add elements to the material to achieve the strength I needed.

The problem I have had with the few parts that do have alloy designation is they use a different classification for alloys than I am accustomed to. Porsche doesn't discuss such things unfortunately. This is why I am thinking these boxes are Almag 35. It would have been much easier to cast and less susceptible to corrosion. It will turn black naturally over time due to the high mag content. I don't know what coatings they used but they did not follow the MIL specs I had to work to and the chemical conversions my grandfather basically invented back in the 30's. I know things like the Italian made Cup I's use a similar alloy to A356.0T6 aluminum but the SM versions use an alloy I don't have a match for. There are no markings on the valve covers or timing chain covers. The aluminum and magnesium valve covers are made from the same tooling as mag and aluminum shrink equally.

I used to make parts for my friend Joe who owned the Targa Florio winning Alfa Typo 33. He actually used to joke and say there are only two foundries in the world he would trust making his mag parts and I was one the other was in Marinello but I was quicker, cheaper and put up with his BS. He used to bring me originals and say make these. I would tell him he needed tooling but wouldn't pay for it but after making multiples, chopping them up and adding material where needed to compensate for shrinkage he spent about the same. I made several parts for his and other similar models for his friends and cars he was restoring. Just about anything you see in yellow/gold I made. These parts were still in good condition even after all these years and when I made the replacements back in the 90's the originals were still for the most part in good condition minus corrosion from exposure to the elements. If he refinished them years earlier they wouldn't have needed to be replaced.

It is amazing that some cars of the day used mag for coolant lines which was not a smart move.

 

@cobalt absolutely stunning to hear this. As a current CPT in the US Army (now reserves), it is VERY cool to hear about history like this, especially when it hits close to home. You should be proud! I know I would be!

 

My grandfather was a very reserved man and didn't care about money or publicity. His notes helped me help my friend and I come up with a new mag sand system that is water and not petrobond based but generates its own water in the mulling process. We can make strong sand with 3% water content instead of the usual 7% and the oxide skin makes for a long lasting deterrent for corrosion. I wish I could get him to do Mil work but he refuses to deal with all the ISO, NADCAP and other BS. He is one of the smartest foundrymen I know other than my grandfather. Maybe it is time to cast some parts for these cars as I had planned on doing before being forced into early retirement.

I have been fortunate enough to live a very colorful life. Seems my decision to settle on 964's was one of the better ones I made.

 

I love all this crazy in the weeds details...

But...

On another note...and back to the original original question...Sort of...

Does anyone have a stack of Porsche parts around that can shoot pics of the old boxes, the 964 boxes, and the 993 boxes so we can see pics and the differences btw them?

That would bring this back down to reality for us lay people with our pea sized brains who just want to turn wrenches and be greasy...you know, the world of duct tape and cotter pins...

 

The right side 964/993 are the same there is a minor change to the Left side AFAIK I will look to see if I have any pictures of the two.

I can see if I can access an earlier aluminum box but everything changed from the old style ramps, chain tensioners and other bits. Seems to me we would be going in the wrong direction. IMO the 964 & 993 parts are a better design irrespective of material choice.

 

Seems to me someone (name starts with A”) needs to oversee getting these cast in magnesium with more ribbing/ structural support. I know, i know - but we can still dream right!


Pete

 

But are they are better design, or just cheaper??? As the son of an automotive engineer, I listened to my father complain about the bean counters making automotive parts worse because the cost per part had to be cut to meet a pre-determined price point. It didn't matter that the engineer specified the part had to be X, it was too expensive. My father worked for GM, and I heard all about things like the Fiero. The original prototype was powered by a Buick Grand National engine, and had custom front and rear suspension bits. It would have been a world class sports car. But then the accountants got involved and suddenly GM had a car with a Chevy Citation drive train in the back, and Chevette POS front suspension.

The timing boxes and chain ramps for the original 901 engine design lasted all the way through the 3.2 with minimal changes and it worked well. Then suddenly they changed it to the 964/993 design. There are lots of fiddily bits in the early timing boxes that aren't in the 964/993 engines. It appears to be a cheaper way of doing it, and cheaper to build.

Just my $.02 on this.

Clay

 

Clay,

Magnesium usually costs considerably more than aluminum to manufacture. I cast both and can assure you the mag choice was made for one primary reason and that is noise. Porsche could never leave well enough alone and are always changing things. Porsche was on a kick to reduce noise and the 964 was a boringly quiet over muffled car stock which IMO also contributed to lower sales. Even the 993 got hydraulic lifters which quited things down even more. We all modify our exhausts to bring back some rumble. Think about it you have a more complicated casting now made in magnesium and all the rubber grommets, gaskets, studs nuts and caps vs an aluminum housing and paper gasket. I don't think it was a cheaper approach from my perspective.

Give me a 964/993 engine anyday over anything prior. If you don't like your engine i can source a nice 3.2 we can swap even trade. I prefer rebuilding them over the earlier versions, The tensioner design alone IMO are worth the change. I don't think the bean counters were counting as Porsche spent a fortune changing these cars and were 85% different than the G bodies. The investment and low sales nearly bankrupted the company. I admit corners were cut but by 92 they fixed those mistakes and continued on. IMO the bean counters kicked in when they brought in a 3rd party to transform their manufacturing processes and just in time manufacturing for the 993 and boxster.

I hope you figure out your issues. I have not had these same experiences and that doesn't mean they can't warp although my knowledge of the material tells me if they do it is more likely from improper installation than the material itself. If you feel aluminum is a better option than best luck. I will take a mag casting over aluminum any day depending on application IMO it is the strongest lightest metal and is greatly misunderstood.

 

I set out this last weekend to investigate my "leaking timing chain case/cover" while also upgrading sagging/smelly motor mounts and the tubular engine carrier. I'd purchased a new gasket kit and hardware and was planing on repairing a leak.

When I dug into the area, I noticed it wasn't was was indicated on my PPI notes at all, which read "sweating timing chain box and cover, needs new gaskets/reseating". The PPI notes is why I purchased the gasket kit and the 1/4" torque wrench in inch pounds to do the job.

What I discovered was the valve cover and oval crank case vent (top rear of the block, as you know) to be the culprit, leaking down onto the chain box and cover. Now, while in there I verified the torque on both timing chain covers, which was a tad low on some nuts.

You can see some oil residue, but I didn't see any leaks coming from either timing chain box, photos from the job this weekend:

If the box/cover was indeed leaking, I'd assume there would be a much bigger mess on the heat exchange/header area.



You can see here where the crankcase breather and valve cover leak from above is pretty evident. I removed and set aside this bracket...which appears to be from the original exhaust. (Side note, whoever installed the Fabspeed RSR setup on this car needs to be smacked. Terrible work...which damaged several pieces and took me an extra hour and a half to correct)

 

^^ the oil around the rear exhaust bracket you removed could be from several things. It appears to be oil and not power steering fluid. I find these pumps need rebuilds by now although another issue is the seal at the rear of the case where the camshaft and the pulley meet usually leaks over time.

The vent hose and gaskets at the top of the engine can make messes and is something everyone should consider looking into at one point. While doing that it is most likely time to consider changing old fuel lines. Once you start to move them they become suspect.

 

I absolutely love the engine. I just want to fix the oil leak. I need to get my E-34 BMW off my lift so I can pull the engine/transmission from my 914 and fix the leak. I bought a new timing box from Porsche, and I am waiting on all the fiddily bits needed to install it. Supply chain issues. :-(

Honestly, this was asked just to see if anyone had done it in response to the warped chain box issue. I am a retired mechanic turned IT guy. I am not a engineer or a metallurgist. So I took your advise and am going to replace everything on the right front corner, including the rocker shaft seals. Yea, I know, shotgun diagnosis. But pulling that engine/transmission combo out of a 914 chassis is a really big undertaking, and I don't want to do it again.

Thanks for the Education everyone. I have learned more about magnesium metallurgy than I ever thought I would.

Clay

 

My wife has used that bear meme all too often....and not just in the "more Porsche parts" category. I love your attitude Clay. We are both lucky to be a part of this group....learning together!

 

See what happens when you get Covid and your booster at the same time. Cooped up inside makes me a little punchy.

Best luck I hope this fixes your problems at least for a few seasons. A 3.6 in a 914 chassis is a heck of a weapon.