Stop Hearing About IMS Failures
11-04-2010, 11:15 AM
#31
Burning Brakes
In that situation going to an "overkill" impeller may solve impeller failure issues at the risk of total engine loss if the water pump bearing fails.
11-04-2010, 11:37 AM
#32
Sounds like you have problems either way if the bearing goes. It's a matter of when you would catch it.
I replaced my water pump when I dropped the engine for the IMS upgrade and all the other stuff, and the new impeller was metal. I checked for damage to the old one and it was fine. I just plan on replacing it every 50K. (I'm already 1/5 of the way there)
Are the OEM replacements plastic or metal?
We could use electric water pumps or have a screen to catch the plastic impeller pieces.
I replaced my water pump when I dropped the engine for the IMS upgrade and all the other stuff, and the new impeller was metal. I checked for damage to the old one and it was fine. I just plan on replacing it every 50K. (I'm already 1/5 of the way there)
Are the OEM replacements plastic or metal?
We could use electric water pumps or have a screen to catch the plastic impeller pieces.
11-04-2010, 11:47 AM
#33
Burning Brakes
Electric water pumps won't work with an M96 due to the design of the jackets surrounding the water pump. We tried this 3-4 years ago with no luck.
Yet again, do not use a mileage point for a service point for the water pump.. Time in service dictates everything. Whether or not the engine is running, the impeller is exposed to coolant 24/7-365 and that time is what makes the impellers brittle and leads to the issues.
For my engine purchasers I require the water pump be changed every 3 years, no matter what pump is used. We had thought about building our own billet impellers from stainless steel, but the liability related to losing a pump bearing and that impeller wiping out an engine was simply too great.. When things go south people like to point fingers and I'd rather not even offer something as give that a possibility of occurring.
Yet again, do not use a mileage point for a service point for the water pump.. Time in service dictates everything. Whether or not the engine is running, the impeller is exposed to coolant 24/7-365 and that time is what makes the impellers brittle and leads to the issues.
For my engine purchasers I require the water pump be changed every 3 years, no matter what pump is used. We had thought about building our own billet impellers from stainless steel, but the liability related to losing a pump bearing and that impeller wiping out an engine was simply too great.. When things go south people like to point fingers and I'd rather not even offer something as give that a possibility of occurring.
11-04-2010, 12:02 PM
#34
[QUOTE=Jake Raby;8028896]
Yet again, do not use a mileage point for a service point for the water pump.. Time in service dictates everything. Whether or not the engine is running, the impeller is exposed to coolant 24/7-365 and that time is what makes the impellers brittle and leads to the issues.For my engine purchasers I require the water pump be changed every 3 years, no matter what pump is used. QUOTE]
But this doesn't apply to metal impellers. I would think once the seal starts to fail, the bearing follows. 3yrs sounds pretty safe.
(I replaced the water pump on the 996 @ 100k, and based on my research it was original. I also replaced the WP on my Benz recently, 12 yrs old, 150k+ mi, still in great shape- go figure. Both DD)
Yet again, do not use a mileage point for a service point for the water pump.. Time in service dictates everything. Whether or not the engine is running, the impeller is exposed to coolant 24/7-365 and that time is what makes the impellers brittle and leads to the issues.For my engine purchasers I require the water pump be changed every 3 years, no matter what pump is used. QUOTE]
But this doesn't apply to metal impellers. I would think once the seal starts to fail, the bearing follows. 3yrs sounds pretty safe.
(I replaced the water pump on the 996 @ 100k, and based on my research it was original. I also replaced the WP on my Benz recently, 12 yrs old, 150k+ mi, still in great shape- go figure. Both DD)
11-04-2010, 12:56 PM
#35
Electric water pumps won't work with an M96 due to the design of the jackets surrounding the water pump. We tried this 3-4 years ago with no luck.
Yet again, do not use a mileage point for a service point for the water pump.. Time in service dictates everything. Whether or not the engine is running, the impeller is exposed to coolant 24/7-365 and that time is what makes the impellers brittle and leads to the issues.
For my engine purchasers I require the water pump be changed every 3 years, no matter what pump is used. We had thought about building our own billet impellers from stainless steel, but the liability related to losing a pump bearing and that impeller wiping out an engine was simply too great.. When things go south people like to point fingers and I'd rather not even offer something as give that a possibility of occurring.
Yet again, do not use a mileage point for a service point for the water pump.. Time in service dictates everything. Whether or not the engine is running, the impeller is exposed to coolant 24/7-365 and that time is what makes the impellers brittle and leads to the issues.
For my engine purchasers I require the water pump be changed every 3 years, no matter what pump is used. We had thought about building our own billet impellers from stainless steel, but the liability related to losing a pump bearing and that impeller wiping out an engine was simply too great.. When things go south people like to point fingers and I'd rather not even offer something as give that a possibility of occurring.
Are the cars coming in with these problems from cold areas? I would think a wider temperature swing would contribute to making the impellers brittle.
11-22-2010, 08:56 PM
#38
I'd rather hear about some company that does a good rebuild of engines with performance parts.
Like mentioned sticking to the sticky would be sufficient for the crowd here instead of waking up the cackling chickens so to speak.
Like mentioned sticking to the sticky would be sufficient for the crowd here instead of waking up the cackling chickens so to speak.
11-24-2010, 01:43 AM
#39
Rennlist Member
As with many of "these" threads.....I see both sides, one being replace and the other to leave well enough alone.......Im confused...
It seems with these cars there are no constants and results vary with each car......kinda like women. Opps did I say that outloud.
It seems with these cars there are no constants and results vary with each car......kinda like women. Opps did I say that outloud.
11-24-2010, 04:19 AM
#40
Burning Brakes
I'd rather hear about some company that does a good rebuild of engines with performance parts.
That used to be our priority.. Now things have changed to "failure control"..Now the only thing we build "New" engine wise are big bore performance engines.. We don't have time for the simple stuff anymore, too busy doing update procedures and repairs.
11-24-2010, 06:28 AM
#42
I figure you do port and polish heads. Do you have any good designs for flowing the head? Have you ever experimented with heart shaped and such at valves openings or is there even room for it in the 4 valve heads? Any better injection system with secondary injectors closer to the head intake for heavy throttle inputs? I just have to figure the stock intake could be made better.
11-24-2010, 11:16 AM
#43
Burning Brakes
pac996,
Yes, we have learned a ton about the port designs used in the various models of the M96 engine. Along the way we have learned that its very easy to upset the critical balance between the intake and exhaust ports margin wise by just doing port work.
When carrying out comparative flow work on the flow bench one is able to see that Porsche greatly altered the intake/ exhaust flow ratios as the engine evolved from the 3.4 to the 3.6 and into the 3.8 and the changes aren't what you'd expect. When you compare these to the values from an X51 head and consider camshaft differences lots can also be learned.
What I have learned first hand is that the majority of port enlargement is not necessary and will actually impair port dynamics, especially in port velocity. Simply making ports larger is a common mistake made by those who haven't gathered the required data from both the flow bench and the dyno and coupled that to the results of the stop watch before and after enhancements are made.
Due to this my port arrangements are much milder than others, I capitalize on port velocity and chamber filling, especially at lower engine speeds as this enhances every aspect of the engine.
In summary, stay away from big ports, because your 4 valve heads don't need them, even with bore sizes as large as 8mm over stock, we don't see the need for super sized ports, even on race engines.
Very slight alterations to the short side of the intake port along with slight port polishing is all thats necessary to make the heads perform at the next level. These changes don't effect the port balance but they will give solid gains on the flow bench that increases port velocity and those changes will be evident on the dyno and at the track, or even on the street.
Bigger isn't better.
BTW- The fuel injector location in the M96 engine is already less than 2" from the intake valve, perfectly positioned.. Its as far down the intake tract as possible in stock form.
Yes, we have learned a ton about the port designs used in the various models of the M96 engine. Along the way we have learned that its very easy to upset the critical balance between the intake and exhaust ports margin wise by just doing port work.
When carrying out comparative flow work on the flow bench one is able to see that Porsche greatly altered the intake/ exhaust flow ratios as the engine evolved from the 3.4 to the 3.6 and into the 3.8 and the changes aren't what you'd expect. When you compare these to the values from an X51 head and consider camshaft differences lots can also be learned.
What I have learned first hand is that the majority of port enlargement is not necessary and will actually impair port dynamics, especially in port velocity. Simply making ports larger is a common mistake made by those who haven't gathered the required data from both the flow bench and the dyno and coupled that to the results of the stop watch before and after enhancements are made.
Due to this my port arrangements are much milder than others, I capitalize on port velocity and chamber filling, especially at lower engine speeds as this enhances every aspect of the engine.
In summary, stay away from big ports, because your 4 valve heads don't need them, even with bore sizes as large as 8mm over stock, we don't see the need for super sized ports, even on race engines.
Very slight alterations to the short side of the intake port along with slight port polishing is all thats necessary to make the heads perform at the next level. These changes don't effect the port balance but they will give solid gains on the flow bench that increases port velocity and those changes will be evident on the dyno and at the track, or even on the street.
Bigger isn't better.
BTW- The fuel injector location in the M96 engine is already less than 2" from the intake valve, perfectly positioned.. Its as far down the intake tract as possible in stock form.
11-24-2010, 11:23 AM
#44
11-24-2010, 11:45 AM
#45
Burning Brakes
There are lots of performance characteristics of the M96 that are exceptional. Unfortunately to benefit from these one must recreate the engine to be more reliable first.
The M96 is a great foundation, once the problem areas are addressed. If this wasn't true we'd not be using the M96 foundation to build our engines from.
The M96 is a great foundation, once the problem areas are addressed. If this wasn't true we'd not be using the M96 foundation to build our engines from.