924Board.org

[Brian Bailey]

The timing belt tensioning pulley on my ’78 924 split apart just as I was pulling into my driveway after a pleasant cruise. I thought this was downright considerate of it, as I didn’t have to hike, and was at idle speed at the time. (I should have paid attention to an increased whirring sound, in retrospect) There was some immediate roughness at idle and a gentle valve ticking, more than her usual tappet noise. I shut it down quickly, discovered the problem, replaced the pulley (just happened to have a new one lying around…) and she seems to run as well as ever. Am I deluding myself? Can I expect a melted piston on my first or subsequent hard drive? I imagine a compression test would indicate bent valves?
Hoping that all is well, she’s also in need of front shocks/struts. Knowing the age of the vehicle (but no idea of the mileage) would I be wise to look for new struts with springs? Any thoughts or recommendations?
Thanks for reading!
B

[Paul]

No worries, forget about it.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

[Chrenan]

On a non-turbo 924, the valves and pistons do not share the same space. So, if you timing belt snaps or tensioner fails, there is no damage done. Just buy a new tensioner and belt and reset the timing correctly and you'll be fine.

Just buy new strut inserts for the front and new dampers for the rear. The springs at the front and torsion bars in the rear are very likely still fine despite high mileage. A good set set of inserts/dampers at all corners will refresh the car nicely.
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1987 951 - M193 Version for Japan

[gohim]

Before you go to install the front struts or inserts, be sure to buy a set of the upper mount bearing assemblies. After all this time the rubber will be collapsed and the upper mount will have dropped down onto the upper spring perch.

To keep this from happening around 1982 or 1983, Porsche released a TB instructing mechanics to add a 6mm washer/spacer between the upper spring perch, and the strut bushing/bearing. You 78 probably does not have these washers, as it probably has the original struts in it. You are going to want to order these from Porsche, or get the equivalent thickness washers from your local hardware store.

[Mike924]

[Brian Bailey]

Thanks for the feedback, folks. Very helpful advice as usual! I feared that valves/pistons would collide - as I bought a dead 931 which had suffered this fate - and thought this was uiniversal to these engines. Mucho gracias!

[johnathan1]

(Yes, old thread revival, lol)

Wait, so the 2.0 base 924 engine is a non-interference engine? I was under the impression that it wasn't...wow, a bit of misinformation going around here...

And for the upper strut mounts...exactly which parts need to be replaced once the upper mount rubber has dropped onto the perch? (My upper rubber ring can be lifted and moved around about 8mm, and I get clunking from both fronts when going into driveways... )
_________________
-1977 924, 4-Spd...Gone
-1987 Toyota Supra Turbo, Pearl White, BPU, 300RWHP @ 10psi.
-1989 Mercedes-Benz 300SEL

WARNING: MAY CONTAIN TRACES OF AUDI OR VW!

[Chrenan]

[gohim]

When the upper strut mount drops onto the upper spring perch and starts grinding, you need to buy new upper struts mounts and the 6mm spacers for both sides of the car.

On 924s the original upper strut mounts consisted of four parts: the upper strut mounting plate, rubber bushing, strut bearing, and a spacer. The rubber bushing, strut bearing, and spacer were replaced by a single part on the 944, which superceeded the three parts on the 924. Porsche added the 6mm spacers during early 944 production (and published a technical bulletin instructing that the spacers be added to every 944 or 924 or 931 that was built without them) to prevent the metal upper strut plate from grinding on the upper spring plate when the rubber bushing collapses.