Failed oil pump pulley...the sad saga of
- Thread starter ByeEnzo
- Start date
shesgotlegs
GT Owner
- Jul 20, 2006
- 1,184
Mine failed at about 12K miles, but that includes about 50 half hr. track sessions and the TX Mile in Goliad. I had it on the lift the other day and checked the oil pump belt tension and also checked for any iron dust (a tell tale sign the pulley splines are wearing out).
2112
Blue/white 06'
MAD IN NC
Proud Owner/ BOD blah bla
last year at the rally during the vampire fluid change by the GT GUYS, dennis did check mine and noticed the tensioner was "hanging up" Disaster hopefully averted.
Mine was discovered last week. The car has 11.7k miles on the clock. As it turned out, it appears that the thread on the oil pump shaft was about half a rotation too short, such that even when the new pulley was put on and the nut secured to the proper torque, the pulley still "moved" a little. A small hard washer was added to take up the slight slack and some red-locktihgt, it is now all good. I feel like I got lucky on this one as it was discovered "accidentally"; otherwise, it would have gone unnoticed until someting bad occurs......
eg1985
GT Owner
Yes, undoubtedly we dodged a bullet on Ed's car. Good thing we just happened to be doing a Whipple install and saw this!:biggrin
When I removed the O/P cover and saw the rusty mess I knew right away something was a-miss. We carefully looked at everything closely and during my inspection I noticed that the oil pump drive pulley was rocking slightly in and out top-to-bottom, side-to-side. After disassembling everything it was apparent that the splines on the sprocket had been whittled down to fine points resembling saw teeth. At first I simply chocked it up to the fact that the retaining nut must have loosened slightly allowing for some movement between the nut's washer face and the pulley flange. We inspected the oil pump driveshaft itself and it was nice and tight with a nice smooth feel; the splines on the shaft of course, being hardened machined steel are still perfect and even have the machine lines still present. We ordered a new pulley, belt, and nut next day air. I then went to reinstall everything; still not feeling satisfied that the root cause of the problem was truly identified. It was upon reinstallation of the pieces that the problem came to light. After installing the new pulley and looking closely, I noticed that the un-machined portion of the driveshaft protruded out slightly beyond the mounting flange of the pulley thereby allowing the nut to get tight on the shaft but leaving about .015 between the nut and the pulley:eek. I added a grade 8 washer with the appropriate I.D, O.D., and thickness; Red Loctite and torqued to spec and the pulley is nice and tight. This problem obviously existed from day one on this car and chances are there are more out there so take some time and carefully check your pulleys guys!
What I saw upon disassembly:
Comparison of the two pulleys, notice the difference in spline sizes:
Notice the unthreaded portion of the driveshaft protruding beyond the pulley flange:
Everything back together with a newly added spacer, new Ford retaining nut, Red Loctite and a witness mark. All buttoned up and ready to run:
When I removed the O/P cover and saw the rusty mess I knew right away something was a-miss. We carefully looked at everything closely and during my inspection I noticed that the oil pump drive pulley was rocking slightly in and out top-to-bottom, side-to-side. After disassembling everything it was apparent that the splines on the sprocket had been whittled down to fine points resembling saw teeth. At first I simply chocked it up to the fact that the retaining nut must have loosened slightly allowing for some movement between the nut's washer face and the pulley flange. We inspected the oil pump driveshaft itself and it was nice and tight with a nice smooth feel; the splines on the shaft of course, being hardened machined steel are still perfect and even have the machine lines still present. We ordered a new pulley, belt, and nut next day air. I then went to reinstall everything; still not feeling satisfied that the root cause of the problem was truly identified. It was upon reinstallation of the pieces that the problem came to light. After installing the new pulley and looking closely, I noticed that the un-machined portion of the driveshaft protruded out slightly beyond the mounting flange of the pulley thereby allowing the nut to get tight on the shaft but leaving about .015 between the nut and the pulley:eek. I added a grade 8 washer with the appropriate I.D, O.D., and thickness; Red Loctite and torqued to spec and the pulley is nice and tight. This problem obviously existed from day one on this car and chances are there are more out there so take some time and carefully check your pulleys guys!
What I saw upon disassembly:
Comparison of the two pulleys, notice the difference in spline sizes:
Notice the unthreaded portion of the driveshaft protruding beyond the pulley flange:
Everything back together with a newly added spacer, new Ford retaining nut, Red Loctite and a witness mark. All buttoned up and ready to run:
Howard
GT Owner
FourFather
GT Owner
Also im slowing my oil pump down due to the rpms the motor is going to turn now. I am machining the shaft down to 1/2 and having it keyed with a 1/8inch keyway and then going to have a new crank mandrel made and im get'n away from the tractor tire belt and going with a gilmer belt with a flanged pulley for the oil pump/crank pulleys to keep the belt from falling off.
That would NOT be a lot of fun on the track at maximum lateral g loads to loose drive, and an have an abrupt weight transfer from the back to the front. Different of course if you were only going in a straight line.
One thing a person could do is a hobbs switch that if the car loses oil pressure it kills spark. I have this set up on my stand alone computer with oil pressure and fuel pressure to save the motor from KABOOM LAND
Howard
GT Owner
How do you get the plastic pump cover off? The Torx screws are very close to other pipes and some of them are not visible, at least when viewed from the bottom when I changed my oil. What's the recommended technique and tools (short Torx?)? Thanks.
Howard
Howard
Your pics show exactly how we reassembled my new pulley with a washer and loctite. Thanks for posting.
Yes, undoubtedly we dodged a bullet on Ed's car. Good thing we just happened to be doing a Whipple install and saw this!:biggrin
When I removed the O/P cover and saw the rusty mess I knew right away something was a-miss. We carefully looked at everything closely and during my inspection I noticed that the oil pump drive pulley was rocking slightly in and out top-to-bottom, side-to-side. After disassembling everything it was apparent that the splines on the sprocket had been whittled down to fine points resembling saw teeth. At first I simply chocked it up to the fact that the retaining nut must have loosened slightly allowing for some movement between the nut's washer face and the pulley flange. We inspected the oil pump driveshaft itself and it was nice and tight with a nice smooth feel; the splines on the shaft of course, being hardened machined steel are still perfect and even have the machine lines still present. We ordered a new pulley, belt, and nut next day air. I then went to reinstall everything; still not feeling satisfied that the root cause of the problem was truly identified. It was upon reinstallation of the pieces that the problem came to light. After installing the new pulley and looking closely, I noticed that the un-machined portion of the driveshaft protruded out slightly beyond the mounting flange of the pulley thereby allowing the nut to get tight on the shaft but leaving about .015 between the nut and the pulley:eek. I added a grade 8 washer with the appropriate I.D, O.D., and thickness; Red Loctite and torqued to spec and the pulley is nice and tight. This problem obviously existed from day one on this car and chances are there are more out there so take some time and carefully check your pulleys guys!
What I saw upon disassembly:
Comparison of the two pulleys, notice the difference in spline sizes:
Notice the unthreaded portion of the driveshaft protruding beyond the pulley flange:
Everything back together with a newly added spacer, new Ford retaining nut, Red Loctite and a witness mark. All buttoned up and ready to run:
I used a short torx bit http://wihatools.com/700seri/725serie.htm Held with a pair of vice grip pliers. I could get my hand up and around to get at them all.
Howard
GT Owner
TO AWSUM
Ford GT Owner
Specracer,
Next time instead of using vise grips to hold the Torx bit, try using a closed end ratchet wrench. Works great for me. If the bit slides in/out of the wrench too much put some duct tape around the bit and wrench. If you need to exert more pressure, use a screwdriver or small pry bar against the end of the bit. Sorry for mentioning it if you've already tried it.
Next time instead of using vise grips to hold the Torx bit, try using a closed end ratchet wrench. Works great for me. If the bit slides in/out of the wrench too much put some duct tape around the bit and wrench. If you need to exert more pressure, use a screwdriver or small pry bar against the end of the bit. Sorry for mentioning it if you've already tried it.
Will this work? For close quarters, it's great for the seats....
http://www.fordgtforum.com/forums/showthread.php?11653-Great-Ratcheting-Wrench!
http://www.fordgtforum.com/forums/showthread.php?11653-Great-Ratcheting-Wrench!
Not a bad idea, I will try. But the vice grips I use are small (5")' and it's nice because the pliers can also be at an angle to clear the cover. Easy to get them tight enough to not slip or damage the bit. Had tried my reg torx sockets, and the loose bit with tiny 5/16 sockets, and flex head ratchet, too long. I'll try the other next winter when I change the belt. Thanks!