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Posted by: rtalich Apr 17 2015, 10:18 AM

Issue just started last night. Just starting out in first gear while slipping the clutch. Once clutch engages at lower RPMs it felt like I was rolling over speed bumps. At faster speeds it seemed fine. Now it is starting to happen more frequent but only at lower RPMs. I have not had a chance to diagnose yet. Anything in particular come to mind?

Thanks
Rob

Posted by: ripper911 Apr 17 2015, 10:24 AM

Loose lug bolts?

My 911 was doing something similar the last time that I drove it, I thought a bearing went bad. Some of the lug boltswere loose, so iI tightened them up. I don't know if it fixed it or not, since it wouldn't crank after that drive, and then the starter went out...

May be a bad wheel bearing?

Hopefully somebody that actually has an answer will chime in.

Posted by: Dave_Darling Apr 17 2015, 11:05 AM

Loose or sheared motor mounts is something else to check. Does the gear shift lever move around a bunch under heavy braking?

--DD

Posted by: rjames Apr 17 2015, 11:07 AM

Bad tire?

Posted by: McMark Apr 17 2015, 01:40 PM

Also could be a slipping clutch. Also, you could drain the transmission into a clean container. Check for chunks. If it's fine, just pump it back in.

Posted by: rtalich Apr 19 2015, 11:47 AM

I think I may have found the problem. The ball joint was still attached. I pulled it slightly and it popped out. Anyone know where I can get parts?


Attached thumbnail(s)

Posted by: rhodyguy Apr 19 2015, 11:57 AM

Pelican, GPR? Might as well r&r the 2 sway bar bushings, where the bar mounts to trunk bottom, while you're in there.

Posted by: messix Apr 19 2015, 12:42 PM

not likely the problem

there are the two little engine to engine bar mounts that can tear apart and you feel a bump when pulling away for a stop and can see the shift leaver move as it happens.

or as said before, loose wheel

Posted by: messix Apr 19 2015, 12:44 PM

when did our trannys start being a wet clutch set up?

Posted by: rtalich Apr 19 2015, 01:05 PM

Thanks! I will do a bit more investigating. Would you happen to to have a pic of what you are referring to?

Posted by: messix Apr 19 2015, 01:57 PM

this is the part. its bolted between the bracket on the engine and the engine bar at the front of the engine.

http://www.pelicanparts.com/catalog/SuperCat/5893/POR_5893_ENGMIS_pg2.htm#item8

http://www.ephotomotion.com/914engine/images/long%20block.jpg

Posted by: Porsche930dude Apr 19 2015, 03:09 PM

check the tires for bulges you might have broken a belt.

Posted by: Dr Evil Apr 20 2015, 09:33 PM

I would be surprised if this was not external to the box. There are so many likely, and common, causes that have already been listed. Check them all and get back with us.

Check the engine mounts by applying a jack under the engine (on wood) and seeing if the engine moves significantly (side shit 73 and up).

Posted by: stugray Apr 20 2015, 10:22 PM

I am surprised that no-one mentioned that you could have a CV joint coming loose.
Crawl under and check them without jacking the car up.
Feel for any loose ends on the axles. They should move along the axis of the axle, but none side to side.

Then jack it up and check again.

Posted by: Dr Evil Apr 21 2015, 07:00 AM

Ha! I thought the second post did. Nope, lug nuts. Good post and I was thinking the same as a first look. Happens too often, especially in the Spring. When I used to sell the CV bolt kits this was the time of year I would be most busy. Everyone should check the CV bolts often as too many of us have had them come loose and beat the hell out of the underside of our cars. I am working on a trans for one right now that messed up the shifter console when the shaft was flying around.

Posted by: stugray Apr 21 2015, 07:07 AM

I had my first race last weekend and in the flurry to get everything ready, the LAST thing from my list (that I was able to complete) was to check the torque on the CVs.
I AM GLAD I DID! as ALL of the bolts required at least a 1/4 turn to reach torque. Some significantly more than that.

Posted by: rtalich Apr 21 2015, 07:13 AM

Thanks everyone for the replies! When I did my initial visual inspection, the only odd thing I found, was what I had posted. I have not had a chance to crawl back under and check the motor mounts but I did order a couple along with the new sway bar bushings.

Did not find anything odd with the CV joints, tires or lug nuts.

Thanks for confirming that it is not an internal transaxle issue!!

Posted by: stugray Apr 21 2015, 08:55 AM

Did you check them with the car jacked up?
If the CVs are in a bind from being fully extended while the wheels are off the ground, you might not be able to tell as easily if they are loose.
Retorque them while you are under there either way.
Clean out the fastener holes BEFORE trying to retorque or you stand a good chance of stripping them (the heads fill up with grime).

Posted by: rtalich Apr 21 2015, 11:02 AM

Thanks! I will check them again tonight.

Posted by: rtalich Apr 27 2015, 09:13 AM

Finally had a chance to work on the car this weekend. Thanks for all your help guys! It was the rubber motor mounts. Both of them were sheared in half!!

Posted by: rhodyguy Apr 27 2015, 09:28 AM

Posted by: stugray Apr 27 2015, 09:52 AM

That is great that you found them!
When I took my engine out the last time I found both of mine broken as well.

However, the broken motor mounts should not cause the behavior that you describe all by themselves (more like a symptom than root cause)
Dont be too surprised if you find that the problem is still there after you replace them.

I would expect broken motor mounts to show thenselves more when starting/stopping or shifting, not driving smoothly over level ground.
Maybe I misunderstood your description of the problem.

Posted by: aircooledtechguy Apr 27 2015, 02:18 PM

You may consider solid mounting your motor so this doesn't happen again. You should be pushing north of 350hp with that beast. . .

Posted by: Dave_Darling Apr 27 2015, 07:48 PM

No, they will cause that behavior. BTDT. The whole drivetrain pivots up and down, slamming the mount brackets against the motor mount bar. WHAM WHAM WHAM WHAM! Most prevalent in 1st gear when the drivetrain is putting the most torque down.

--DD

Posted by: messix Apr 27 2015, 11:07 PM

yup btdt too



told ya so !

Posted by: stugray Apr 27 2015, 11:19 PM

So do you think the engine is "hopping" up and down when it does this or twisting/rocking?

I remember driving my fathers TR4 that had a broken motor mount.
The symptom was: when making a right turn, the steering would not self center.
Because the engine was leaning up against the steering shaft - DOH!

Edit - just thought about this.
If both axles are torquing to push the car forward, then the engine is trying to raise upwards in the front.
So with a high HP engine, the front mounts need to hold the engine DOWN.

Posted by: messix Apr 27 2015, 11:54 PM

yep, no clutch drop starts or this happens.

Posted by: Dave_Darling Apr 28 2015, 08:05 PM

Hopping. The whole thing pivots around the drive axles, lifting the front up. It gets to a certain point and then falls--possibly because the wheels are indeed turning. The motor falls back down onto the mounts. Then the process starts over again. The sound and feel was way too violent for it to just be rocking.

--DD

Posted by: sixnotfour Apr 28 2015, 09:46 PM

chain it down like a muscle car...chevy had a kit with a cable so the motor couldn't lift beyond the rubber limit...ya around 1967

Posted by: messix Apr 28 2015, 09:50 PM

btdt

Posted by: rtalich Apr 28 2015, 09:52 PM

Yep!! I don't think these will last long at all! I wasn't sure about using the solid mounts from an engineering standpoint. You take away that 'floating' point and make it static. There might be a failure develop somewhere else. But I may have no choice.

Posted by: McMark Apr 28 2015, 11:32 PM

Take off the turbo and pin the throttle to only open 50%. Then your mounts will last.

Posted by: rtalich Apr 29 2015, 07:13 AM