Oil pump gear sheared off and belt piled up
07-07-2012, 01:56 PM
#31
Rennlist Member
07-07-2012, 03:07 PM
#33
Three Wheelin'
Join Date: Mar 2010
Location: Colorado Springs, CO USA
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My condolences.
FWIW, you can also check to see which cylinders have bent valves by pulling the cams and then running a leakdown test. The bent valves won't close properly, so you'll see low pressures in those cylinders.
FWIW, you can also check to see which cylinders have bent valves by pulling the cams and then running a leakdown test. The bent valves won't close properly, so you'll see low pressures in those cylinders.
07-07-2012, 03:29 PM
#34
Nordschleife Master
07-07-2012, 06:45 PM
#35
Three Wheelin'
Brad,
The heads are the same but I would reuse the original heads on your 89 since they are a better design. The 87-88 R1 heads had issues that would cause the heads to crack at the mounting boss, causing coolant and engine oil to mix. In 89 they beefed that area up by 20mm to prevent the cracking issue. Also, 89+ cars have the longer head bolts (by 20 mm) compared to the ones used on the 87-88 heads. I would actually buy brand new head bolts when you get ready to put the heads on.
If you have an issue with finding a trust-able machine shop over there you can send the heads here to Roger. I know two shops here that have done 928 S4 heads for me that I trust. Its about $830 to $900 for all new SI guides (people use after market guides than buying them new from Porsche), 3 angle valve job and resurfacing both heads.
The heads are the same but I would reuse the original heads on your 89 since they are a better design. The 87-88 R1 heads had issues that would cause the heads to crack at the mounting boss, causing coolant and engine oil to mix. In 89 they beefed that area up by 20mm to prevent the cracking issue. Also, 89+ cars have the longer head bolts (by 20 mm) compared to the ones used on the 87-88 heads. I would actually buy brand new head bolts when you get ready to put the heads on.
If you have an issue with finding a trust-able machine shop over there you can send the heads here to Roger. I know two shops here that have done 928 S4 heads for me that I trust. Its about $830 to $900 for all new SI guides (people use after market guides than buying them new from Porsche), 3 angle valve job and resurfacing both heads.
07-07-2012, 07:39 PM
#37
Inventor
Rennlist Member
Rennlist Member
Ouch. Bummer Brad.
I initially thought Bill might be correct, but it looks like there's some droop between the cam gears, and I can't imagine some of the shredding belt didn't get in between the crank gear and the remains of the belt. I'm amazed that the belt is still on there, though.
(I would like to imagine that mass slowed the engine to a stop...)
Not sure if will make a difference, but with a stock tensioner system, likely all that shredded belt would likely have stacked up near the crank, at the stock tensioner arm.
A fraction of a second before all the other lights came on.
I initially thought Bill might be correct, but it looks like there's some droop between the cam gears, and I can't imagine some of the shredding belt didn't get in between the crank gear and the remains of the belt. I'm amazed that the belt is still on there, though.
(I would like to imagine that mass slowed the engine to a stop...)
Not sure if will make a difference, but with a stock tensioner system, likely all that shredded belt would likely have stacked up near the crank, at the stock tensioner arm.
A fraction of a second before all the other lights came on.
07-07-2012, 11:11 PM
#38
Drifting
Thread Starter
ya I did not here any warning.
It actually sounded like it ran out of gas and as I stepped on and of the gas a couple times I could here the dead blaaa blummm blaaa blummm so it was still turning over.
I clicked it into neutral and the engine went quiet so that I just heard the trans/diff as I coasted to the side of the road.
It happened sudden and I knew it was bad.
It actually sounded like it ran out of gas and as I stepped on and of the gas a couple times I could here the dead blaaa blummm blaaa blummm so it was still turning over.
I clicked it into neutral and the engine went quiet so that I just heard the trans/diff as I coasted to the side of the road.
It happened sudden and I knew it was bad.
07-07-2012, 11:24 PM
#39
Nordschleife Master
Being an 89, you will have bent valves.
edit: removed wrong info on 87 being non-interference - the car I thought survived belt failure compression-tested ok, and ran ok. Leakdown however a couple of months later showed bent valves
edit: removed wrong info on 87 being non-interference - the car I thought survived belt failure compression-tested ok, and ran ok. Leakdown however a couple of months later showed bent valves
Last edited by Hilton; 07-20-2012 at 10:12 PM.
07-07-2012, 11:39 PM
#40
Rennlist Member
07-07-2012, 11:44 PM
#41
Nordschleife Master
Part-way through 88 model year the piston design changed to have a shallower dish, and the compression ratio bumped to true 10:1.
US 85/86 had 10:1 compression so are interference too, although Australian S3's (and German S3's) are lower compression too and may not be interference.
07-07-2012, 11:45 PM
#42
Rennlist Member
That is exactly how my 86.5 looked. I was lucky though, smelled plastic burning and shut car off. Everything was still in time but had to replace gear, cover and belt. Hope no valves got bent.
07-07-2012, 11:50 PM
#44
Rennlist Member
I'm sorry to see the carnage Brad. I followed all your recent rebuild work and know how much work you put into the motor. Hope you get lucky and it's not as bad as you might be thinking.
07-08-2012, 03:07 AM
#45
Drifting
Thread Starter
Originally Posted by Hilton
Early S4's had a deeper piston dish, and their true compression ratio is around 9.3:1. The Porsche Tech spec book says their allowable compression range is 10:1(-0.7). Not plus/minus, just minus
Part-way through 88 model year the piston design changed to have a shallower dish, and the compression ratio bumped to true 10:1.
US 85/86 had 10:1 compression so are interference too, although Australian S3's (and German S3's) are lower compression too and may not be interference.
Part-way through 88 model year the piston design changed to have a shallower dish, and the compression ratio bumped to true 10:1.
US 85/86 had 10:1 compression so are interference too, although Australian S3's (and German S3's) are lower compression too and may not be interference.
This is just something that is going to force me to take it to the next level
and It also taught me a lesson. Thank God its not a hole in the block.
I am trying to keep most of the hardware stock and the EZK and LH and other parts that I have swapped out,
I am keeping so that the car can be brought back to stock with all the original equipment.
It will just need a new harness and plug wires.
I think this time I will check the bottom end again and possibly throw rod bearings in it as I haven't done that yet.
I haven't found my dream induction yet but
I already have the wires for the NOS under the console to my spare switch and the extra on/off module in place. ILL need 2
If I had 800 HP I would not even be close to a fast car in this town as there are 1500 HP camaro's and 1000 HP callengers let alone the 200 mph ZR1 vets.
so I'm not building for high HP
BUT THATS OK because we don't compare a porsche to others because . THERE IS NO OTHER
