Cracked Power Plant Frame (PPF)

Hammer · Postby **Hammer** » Sun Jun 27, 2010 10:30 pm

Just an FYI for other owners...

I took my SP to Mania last Wednesday for its regular service and for David (Raddatz) to source an annoying intermittent metal ticking noise.

David found the noise was caused by a cracked PPF. Apparently for hi-powered MX5, it can happen. Not that I call my SP over-powered. It's only got stock boost (8psi). Nonetheless, the crack was along one of the four bolts that hold the PPF into the gearbox (at one end) and the diff (at the other). And needless to say, the whole thing was replaced.

For those not familiar with the PPF (Power Plant Frame), its the frame that directly connects the gearbox to the diff and it's made out of light aluminium. The engineers' thinking behind this is for an instant response when the floor is planted. Keeping the distance between the gearbox and diff constant, elimating lag on the drive shaft - so I've read from the MX-5 book.

I recommend you get your PPF checked next time your car is in for service (specially if you've turboed or supercharged it).

PPF

wun911 · Postby **wun911** » Mon Jun 28, 2010 2:33 am

how will they fix it weld it back or do you need a new one???

Postby **mx52nv** » Mon Jun 28, 2010 2:38 am

wun911 wrote:how will they fix it weld it back or do you need a new one???

Hammer wrote:And needless to say, the whole thing was replaced.

Hammer, I did one many years ago and replaced it. Mine cracked at the diff end though.

Les

bruce · Postby **bruce** » Mon Jun 28, 2010 11:04 am

There would have to be twenty bucks worth of recyclable aluminium in that PPF.

Hellmun · Postby **Hellmun** » Mon Jun 28, 2010 11:22 am

My diff brace sits low and transfers some NVH but I wonder if that would prevent the cracking. From memory it's a carbing item. It ties the diff to the subframe where the ladder brace bolts on.

sliq · Postby **sliq** » Mon Jun 28, 2010 1:56 pm

i think you got the beatrush one hellmun. it's the triangular one, right?

see here

http://www.good-win-racing.com/Mazda-Pe ... -0553.html

Hammer · Postby **Hammer** » Mon Jun 28, 2010 4:49 pm

Here's the PPF removed from my SP

Garry · Postby **Garry** » Mon Jun 28, 2010 8:43 pm

Mine cracked too a couple of years ago, but at the diff end. Some new engine mounts and a new used PPF really tightened up the driveline.

Hellmun · Postby **Hellmun** » Mon Jun 28, 2010 8:50 pm

That's definitely the one but it doesn't feel like aluminium when your holding it. It must be really thick. It's completely unmarked which is why I always forget the brand..... needs new longer bolts to fit too. You hear a lot more whining with it... had me paranoid I'd broken something for the longest time until I got used to it.

FMS01 · Postby **FMS01** » Thu Jul 01, 2010 9:34 pm

Ohh, maybe thats the source of the noise in mine.. (NA6T) I've been thinking stuffed engine mount but possibly it's the PPF. I get lots of vibration through the gear knob and metal pings and clangs from under the floor near the gbox.

Julian

93_Clubman · Postby **93_Clubman** » Mon Jul 05, 2010 2:48 pm

Crikey Al - you have all the luck - not!

Postby **Okibi** » Thu Jul 08, 2010 12:14 am

I've seen the PPF "boxed" more permanently in Japan. Not sure if Bluebear would approve.

Dave · Postby **Dave** » Thu Jul 08, 2010 12:18 am

Borked wrote:http://www.good-win-racing.com/Mazda-Performance-Part/15-1006.html
Might be worth looking into, if you desire to stiffen this part up so it doesn't happen again ?

Mine cracked too (also at the diff end...); looked just like yours Hammer...
I looked at the goodwin brace, however it does nothing to reinforce the crack area. I have fitted the beatrush brace mentioned earlier (sounds like I'm driving an old pommy sports car again with all that drivetrain noise!). I am hoping that it restricts the tendancy to crack too, as well as reduce axle tramp (and once the new clutch is in I might be able to find out! :mrgreen:

).

Cheers,
Dave