blown engine
#661
Rennlist Member
#663
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Yup, I asked the machine shop to magnaflux them. They found cracks on the bank 1 cam sprocket, caused by metal ingestion in the bank 1 scavenge pump. Just ordered a new one from Sunset - $160 for a freaking sprocket ![grr](https://rennlist.com/forums/graemlins/cussing.gif)
The slots are for adjusting the cam timing.
Also got my rotating assembly back from the machine shop. They said it's balanced to 1g-in (0.03 oz-in). I asked if they meant 1oz-in but they said it's really 1g-in. Sounds too good to be true?
![grr](https://rennlist.com/forums/graemlins/cussing.gif)
The slots are for adjusting the cam timing.
Also got my rotating assembly back from the machine shop. They said it's balanced to 1g-in (0.03 oz-in). I asked if they meant 1oz-in but they said it's really 1g-in. Sounds too good to be true?
#664
Rennlist Member
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Yup, I asked the machine shop to magnaflux them. They found cracks on the bank 1 cam sprocket, caused by metal ingestion in the bank 1 scavenge pump. Just ordered a new one from Sunset - $160 for a freaking sprocket ![grr](https://rennlist.com/forums/graemlins/cussing.gif)
The slots are for adjusting the cam timing.
Also got my rotating assembly back from the machine shop. They said it's balanced to 1g-in (0.03 oz-in). I asked if they meant 1oz-in but they said it's really 1g-in. Sounds too good to be true?
![grr](https://rennlist.com/forums/graemlins/cussing.gif)
The slots are for adjusting the cam timing.
Also got my rotating assembly back from the machine shop. They said it's balanced to 1g-in (0.03 oz-in). I asked if they meant 1oz-in but they said it's really 1g-in. Sounds too good to be true?
#665
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The bank 1 scavenge pump ingested the debris and was chewed up inside. That put a lot of pressure and shock on the bank 1 cam sprocket that drove it.
![](https://cimg3.ibsrv.net/gimg/rennlist.com-vbulletin/1120x2000/0628151729a_dc2d03083cc4bd1f68d94b4569e1db2c1ea0ff83.jpg)
![](https://cimg1.ibsrv.net/gimg/rennlist.com-vbulletin/1120x2000/0628151729d_d4e8db08ca3535a6adf6161428fd8a28de34d101.jpg)
![](https://cimg2.ibsrv.net/gimg/rennlist.com-vbulletin/2000x1124/0628151729b_5d40aaa088ffa22fea3a8079ef0144bab7c0ff67.jpg)
#666
Rennlist Member
#667
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Ahsai
I got a spare cam sprocket from my original engine could have posted over to you, is it too late to cancel your order?? I'm in uk so might take a week or so to reach you though??
I got a spare cam sprocket from my original engine could have posted over to you, is it too late to cancel your order?? I'm in uk so might take a week or so to reach you though??
#668
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I don't think the timing slipped, if you look at the paint on the right hand bolt it lines up with the paint on the sprocket, I think this engine has had its timing reset before at some point, the mark you see was probably the original factory setting but I'm pretty sure it's been changed at some point?? Doesn't the paint indicate an engine returned to the factory under warranty for rebuilding or was that blue paint, I read that somewhere ?? Wonder if Porsche recorded the engine numbers or recalled cars and details??
#669
Rennlist Member
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I don't think the timing slipped, if you look at the paint on the right hand bolt it lines up with the paint on the sprocket, I think this engine has had its timing reset before at some point, the mark you see was probably the original factory setting but I'm pretty sure it's been changed at some point?? Doesn't the paint indicate an engine returned to the factory under warranty for rebuilding or was that blue paint, I read that somewhere ?? Wonder if Porsche recorded the engine numbers or recalled cars and details??
#670
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Sorry for the suspense. The yellow paint was put on by my machine shop to show me where the cracks are. They removed it from the cam to magnaflux it and put it back on the cam randomly hence the random bolt locations.
The failure was probably due to bad luck but the only way to prevent timing chain failure is to replace them.
Noz, thanks for your offer but I think I'm good for now as I ordered it last week and it's already on its way.
The failure was probably due to bad luck but the only way to prevent timing chain failure is to replace them.
Noz, thanks for your offer but I think I'm good for now as I ordered it last week and it's already on its way.
#671
Rennlist Member
#672
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Jake offes a preventive maintenance package that includes changing out the timing chains (the ones between the crank and the cams) w/o splitting the block. In this case though, it's the ims chain that's between the crank and the ims and that requires splitting the engine case to replace so most likely it only makes sense if you're doing a full engine rebuild.
#673
Rennlist Member
#674
Rennlist Member