Beast lives after oil pump failure!
Thread Starter
Instructor
Joined: Jun 2001
Posts: 122
Likes: 0
From: Columbia, SC
Beast lives after oil pump failure!
Last week the oil pump seized and with a quick zipping sound munched the timing belt. I know most would think : bent valves, etc. I put in a new pump and timing belt, did a compression check, and it started back up like nothing ever happened. My car must have nine lives. It is amazing how lucky it has been, it has had a belt break before. I guess this could start the interference engine debate again. My car apparently is not an interference engine. If only SITM were this weekend....
Drifting
Joined: May 2001
Posts: 2,747
Likes: 3
From: Owasso, OK
Bruce,
Great news. We need to save all the OB's we can. Concerning the interference/noninterference issue, all 16 valve engine should be noninterference IF the heads are original and have not been machine more than .4mm as stated on page 15-19 of the factory service manual.
Dennis
Great news. We need to save all the OB's we can. Concerning the interference/noninterference issue, all 16 valve engine should be noninterference IF the heads are original and have not been machine more than .4mm as stated on page 15-19 of the factory service manual.
Dennis
Photoshop Bully
Rennlist Member
Rennlist Member
Joined: Feb 2003
Posts: 7,803
Likes: 2
From: Southern NH
Along time ago, a friend of mine worked at a euro car dealer. He witnessed something sad, but it says alot for Porsche engineering. The owners friend had just crashed his 928 hard in the nose. He wanted to make sure it was totaled, so he smashed the oil pan and started the car. My friend told me the car idled for 45 minutes before it seized! My friend and I had nothing at all to do with this, so save me the soapbox speeches. I still cringe when I think about it.
Drifting
Joined: May 2001
Posts: 2,747
Likes: 3
From: Owasso, OK
Old & New,
As in this case, there have been many later 16 valve engines that have had timing belt disasters without valve damage. There has to be another variable (overmachining, thrown valve?) thrown in for the ones that did have damage. Porsche recognized this when they built the engine and included measuring blocks on the outside of the head to make sure they weren't overmachined. How many machine shops know the specs or what the indicators are there for? Additionally, the timing belt changing instructions for all 16 valvers does not require prepositioning the cams (due to the non-interference) like the 32 valvers.
"(till 78?) *are* intersection."
This statement has me stumped. The 78 MY was the first real production year. Are you saying that ALL 16 valvers are interference?
Dennis
As in this case, there have been many later 16 valve engines that have had timing belt disasters without valve damage. There has to be another variable (overmachining, thrown valve?) thrown in for the ones that did have damage. Porsche recognized this when they built the engine and included measuring blocks on the outside of the head to make sure they weren't overmachined. How many machine shops know the specs or what the indicators are there for? Additionally, the timing belt changing instructions for all 16 valvers does not require prepositioning the cams (due to the non-interference) like the 32 valvers.
"(till 78?) *are* intersection."
This statement has me stumped. The 78 MY was the first real production year. Are you saying that ALL 16 valvers are interference?
Dennis
Trending Topics
Rennlist Member
Joined: Dec 2002
Posts: 1,975
Likes: 0
From: Southern New England
Dennis,
Interesting. I just went back and read a bunch of old posts on the topic. It seems that there is a lot of misinformation out there... which I apparently had subscibed to.
The appearance of interference appears to be concurrent with either the 10.4:1 compression 86, or the 4-valve. Anecdotally, the RPM may play a part in the equation, also.
<flamesuit> It also appears that there has been a lot of unwarranted hand-wringing regarding the service interval in these earlier non-interference engines! </flamesuit>
Interesting. I just went back and read a bunch of old posts on the topic. It seems that there is a lot of misinformation out there... which I apparently had subscibed to.
The appearance of interference appears to be concurrent with either the 10.4:1 compression 86, or the 4-valve. Anecdotally, the RPM may play a part in the equation, also.
<flamesuit> It also appears that there has been a lot of unwarranted hand-wringing regarding the service interval in these earlier non-interference engines! </flamesuit>
Rennlist Stories
The Best Porsche Posts for Porsche Enthusiasts
Every Era of 911 Owner Explained in One Sentence
Verdad Gallardo
Thinking of Buying a Porsche? Do These 10 Things First
Joe Kucinski
Pixar Pals Turned Into 1-of-1 Porsches!
Michael S. Palmer
Theon Goes Full Carbon Fiber With Stunning New Build
Verdad Gallardo
Genius Porsche-Themed Gifts That'll Make Any Dad or Grad Smile
Joe Kucinski
10 Used Porsches Are Selling for Way Too Cheap
Joe Kucinski
Tuner Is Converting Porsche 911s Into Shooting Brakes
Verdad Gallardo
This Coachbuilt Creation Is A Modern Take on the Legendary Porsche 917
Verdad Gallardo