This ain't right - is it timing belt related?
11-03-2015, 12:40 PM
#31
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Every 87 I have ever worked on had the later 87+ water pump if the standard de-tensioner was used. As the 87+ water pump comes with the brace, without the brace must have been fitted at the factory or an owner removed it.
My own early 87 has the brace but also has had a water pump change.
I have converted two 86 cars to the later de-tensioner and WP which as Dave says requires more than just a WP change.
If you use a PKtensioner you can use either the early or late water pump.
IIRC when rebuilding water pumps the re-builders could modify an early WP casting to be used as a later casting - in this case the bolt hole would not be present.
My own early 87 has the brace but also has had a water pump change.
I have converted two 86 cars to the later de-tensioner and WP which as Dave says requires more than just a WP change.
If you use a PKtensioner you can use either the early or late water pump.
IIRC when rebuilding water pumps the re-builders could modify an early WP casting to be used as a later casting - in this case the bolt hole would not be present.
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Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
11-03-2015, 01:06 PM
#32
Three Wheelin'
Thread Starter
Roger,
Interesting. The part number on the invoice for WP on the timing belt / WP job is 928 106 015 MX. That shows up on a number of sites as a remanufactured WP. Could be that I have one of those where the pre-87 casting was modified for use in 87+.
Interesting. The part number on the invoice for WP on the timing belt / WP job is 928 106 015 MX. That shows up on a number of sites as a remanufactured WP. Could be that I have one of those where the pre-87 casting was modified for use in 87+.
11-03-2015, 02:16 PM
#36
Rennlist Member
OK. New question. How bad is it to run a pre '87 waterpump on an '87 S4 auto, if that is in fact what happened?
The car has been running like a dream. The timing belt and waterpump job was done in January of 2013 and the car really only has about 7500 miles on it since done. I don't really want to open it up if I don't have to.
The car has been running like a dream. The timing belt and waterpump job was done in January of 2013 and the car really only has about 7500 miles on it since done. I don't really want to open it up if I don't have to.
the shoulder bolt is CRITICAL , so i replace it every time. i had one break off on disassembly, (lucky) as if it had broken while operating, it would be a huge mess . HUGE!!! So, always get a new one of those on replacement.
11-03-2015, 11:37 PM
#37
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However, as you have noted, you've got another problem now: a rebuilt water pump.
If the water pump was sourced through Porsche then it will have a plastic impeller. If the water pump was sourced through other suppliers then you can't be sure unless you pull it.
If you can't be sure that the impeller is plastic, then you really, really, should dig in and remove the water pump. A metal impeller rebuilt pump sourced after 2007-ish has about a 3 out of 4 chance of beginning to eat (or almost finishing to eat) your block after 7500 miles.
A plastic impeller on a rebuilt pump has a 3 out of 4 chance of beginning (or finishing) to munch the plastic impeller on the block.
Now, you can check the pump for the most common rebuilt issue. Pull the driver's side belt cover and get a small inspection mirror. There is a weep hole in the pump casting on that side of the pump (on the 'ribbed' boss that supports the shaft.) If there is ~2mm of clearance between the forward edge of the hold and the trailing edge of the belt pulley then you are ok. If the edge of the belt pulley is in-line with, or occludes, the leading edge of the weep hole then you have impeller-to-block contact.
The weep hole can be hard to find unless you know where it is: thus the small mirror. I use a borescope for this diagnostic.
11-04-2015, 09:33 AM
#38
Three Wheelin'
Thread Starter
Dave,
With your description of waterpump failures, it sounds like you are saying we have to change our waterpumps every 5000 to 7500 miles. That can't be right. Or am I reading it wrong.
Also, if it is metal on metal, could a sound test be used (like a bar on the pump held up to the ear) to verify munchingness. That's not a word, but you know what I mean.
With your description of waterpump failures, it sounds like you are saying we have to change our waterpumps every 5000 to 7500 miles. That can't be right. Or am I reading it wrong.
Also, if it is metal on metal, could a sound test be used (like a bar on the pump held up to the ear) to verify munchingness. That's not a word, but you know what I mean.
11-04-2015, 12:51 PM
#39
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that isnt accurate. ive used about 4 of them metal pumps and 2 of the plastic impelers. the plastic impellers just start spinning on the shaft and dont move in or outward. the metal ones make noise and leak if the bearing goes bad. ive seen one metal impeller pump that migrated into the block , but we caught it before it totally destroyed the block (scots car) but it did some damage, but didnt effect cooling in his race car .(street or race use) .
Ill probably use the Gebe pump on my waterpump project.
Ill probably use the Gebe pump on my waterpump project.
11-04-2015, 02:41 PM
#40
Nordschleife Master
11-04-2015, 10:07 PM
#42
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Right. Rebuilt only.
Kibort: plastic impeller rebuilts can also migrate into the block. I have a couple in my send-to-Stanke pile with ground down plastic impellers.
Plastic spinning on the shaft can happen no matter what; new or rebuilt.
Kibort: plastic impeller rebuilts can also migrate into the block. I have a couple in my send-to-Stanke pile with ground down plastic impellers.
Plastic spinning on the shaft can happen no matter what; new or rebuilt.
11-04-2015, 10:40 PM
#43
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i run the pre 87 water pump on my engine. i think it has to do with the tensioner set up i had which was originally from the holbert car.. (which was a hodge podge of 87 and 86 technology) the way the tensioner mounts is different on a raised boss and the shoulder bolt. you just cant change to an S4 pump now, as it probably is set up like mine (and the pre 87s) where there is a sholder bolt mount now for the tensioner. (the S4 87s had the different mount and that support bracket)....
the shoulder bolt is CRITICAL , so i replace it every time. i had one break off on disassembly, (lucky) as if it had broken while operating, it would be a huge mess . HUGE!!! So, always get a new one of those on replacement.
the shoulder bolt is CRITICAL , so i replace it every time. i had one break off on disassembly, (lucky) as if it had broken while operating, it would be a huge mess . HUGE!!! So, always get a new one of those on replacement.
Just my $0.00928
