John Veninger

Well it's time to tell the sad story from the Summit Point race.
Around lap 14 the car was getting a bit hot and some backfiring. I decided to back off a bit and see if I could finish the race. Well I finished lap 16 and went into turn 1. As soon as I turned in, the car just died. Race was 19 laps.

Towed back to the paddock knowing that it wasn't going to be good.
Here is what we saw.



Removed the cover:



The water pump shaft and bearing feel just fine.



So it appears that the pressed fit pulley "fell off the shaft". Has anyone had this type of failure??
No, it wasn't a China pump. Rebuilt Porsche pump from the vendor I've used for several pumps on my other motors. Next one gets the pulley WELDED on!
So I now have a new winter project of pulling the heads off of a "new" stroker motor and doing another vale job.

Anyone have any good S4 exhaust valves? I'll need between 1- 16. Going to order the 968 valves once I get the heads off.

In the end it just sucks

goodspeed928

My car has bin down for 8 weeks now.
The waterpump was BAD out of the box.
I put in that one in 4/12/07

John Veninger

Same type of failure?

marton

That was real bad luck.
Anyway since you will probably take the motor out it maybe a good time to review your bottom end arrangements to see if there is scope for improvemment?

Marton

John Veninger

The motor is only two races old

cdbtx

Don't feel bad John - I'm pulling my engine tonight and only 12 days till race day. Looks like a blown headgasket, but I'll know more tonight... Geeeeeeeeeeezzzzz.. 10 hours a day at the office, 2 hours doing the charity stuff, now this... But then again, better to discover it now than during the race.

After working till 10pm last night - the first thought I had this morning was to sell the car... but I know that the first time I get it on the track, those thoughts disappear quickly!

John Veninger

I don't feel bad, I feel pissed.

All part of the "racing experience", right?

Mike Frye

Let me say that watching John that day start to take this thing apart there in the paddock was a study in composure. I don't know how he kept from losing it.

How you maintain and even keel in the face of something like this is beyond me.

Good luck and hopefully I'll get to see you run SP or another track in the spring!

Anyone ever seen this from a WP before?

worf928

I've got a bad water pump in my '91 and a suspect pump in the GTS. I'll be pulling the one in the '91 in November. I'll check for the modes of failure.



John, my condolences on another overly-short race weekend.

mark kibort

that does suck. did it die from overtemp or did it die for belt slipping? it could have only slipped a couple of teeth if the pulley was spinning on the shaft.
i guess its hard to do a compression test, without the pully, but maybe you can wedge it back on and reroute the belt and do one to make sure you did damage.
sorry to hear about this. it seems the only pumps that seem to hold up are the rebuilt ones that anderson sells. I forget the rebuilder name , but they seem to make a decent one.

ive had my share of out of the box, and premature water pump failures! maybe your right, time for a spot weld on the front and back of these pesky things!

mk

John Veninger

Pulley went forward, belt wedged, t-belt teeth sheered off at the crank, valves bent, motor shut down.

We did bang the pulley back on at the track and put on a belt. Just cranking it over by hand was enough to let me know we were done

Jim bailey - 928 International

The highs are much higher but the low can be much lower nothing about being on the track is AVERAGE. Sorry to hear about your problems.

Bill Ball

Oh, crap!

Here's something that I've been wondering for awhile. Can anyone explain why the impeller and pulley could not or should not or are not pinned to the shaft? Considering the terrible effects of these things coming loose, and it happens often enough that I am worried about it, I think they should be pinned.

dr bob

John--

Sorry for your loss. I cry for the time wasted/needed for rebuilding when this stuff happens. Racing redefines the limits of consequential damages. A cheap part fails and there is almost instantly 1000x the part cost in other damages.

Bill--

I'd be concerned about weakening the shaft with a hole for a pin. The stress on the front end of the shaft is significant at times with the belt tension and all. Well, maybe not too bad because the WP is sort of on the slack side, but you get the idea. Maybe a small roll pin right out at the end would do the trick.

A little tack weld with the tig would keep the pulley in place. Wouldn't take much, but it would make that the last use for that pump since the pulley can no longer be pressed off.

Mark Anderson

Sorry to hear that. I'm sure you are more than frustrated. I do have some good used valves you can have n/c. I see no record of selling you a rebuilt pump in the past 6 years so I am assuming it is not one of ours.
See you at Sharktoberfest,