Question for the Quad 4 gods

[Toyguyz]

I have a question regarding an engine gremlin...

First of all, my car runs great, performance is as to be expected from a Quad 4, no lights flashing just the following symptom.

Symptom:
Start the car up and there's a rattle sound that seems to be in the timing chain area right about where the gear at the intake cam is. It was taken back to the shop that did the rebuild and they pulled the cover, found the long tensioner on that side had a small piece at the top cracked so they replaced it They put it all back together then started it and the noise was still there.

Now here comes the gremlin part... When the steering wheel is turned slightly in either direction the rattle goes away? Then when you let go of the steering wheel and center it back up the rattle comes back. The rattle is in the same place and sounds like it's at the timing chain assembly top where the intake cam gear is.

This one has the guy at the shop stumped and he has someone else coming in to get a second opinion. (The good news is no charge for parts and labor because he built the motor in January and stands behind his work.)

The only thing common to the symptom is that the power steering unit is driven by a belt off the intake cam. But when it's running and you watch the pulley while someone is turning the wheel, there is absolutely no movement or wobble on the pulley.

Since leaving the shop a little while ago and getting home I had a thought of what it might be but wanted to see if anyone here has ever run across something like this in their Quad 4 adventures.
I'm thinking maybe he needs to retorque the intake cam cover? Maybe it's a slight movement of the cam caused by improper torque.

OK Quad 4 gods, Whatcha' think??

I look forward to any ideas you have to offer!
Thanks,
Roy (toyguyz)

OH, for those that may ask....
Yes I finally got past the 500 miles and yes I did run it through the gears and was impressed by what this 4 cylinder has to offer!

[DominionTuner]

Well you beat me to my own suggestion, I was thinking maybe it has to do with the powersteering pulley as well. Personnally, my 95 came with a P/S pump instead of a pulley, I definetly like it better than the prior setups I've seen and no offense to anyone using the pulley system. Sorry I can't help you on this one.

[Toyguyz]

Originally posted by DominionTuner
Well you beat me to my own suggestion, I was thinking maybe it has to do with the powersteering pulley as well. Personnally, my 95 came with a P/S pump instead of a pulley, I definetly like it better than the prior setups I've seen and no offense to anyone using the pulley system. Sorry I can't help you on this one.

My 95 has a pump also but the pump is driven by a pulley at the end of the intake cam to the pump via an external drive belt.

[4kQuad]

My guess is you are chasing a traveling sound. Get a 10 doller Docters stephascope, put it to the base of the Power streaing unit with the car running. I think the bearing in the Pump is going allowing for a viberation to be created.

The viberation is then traveling the lenght of the shaft before you hear the sound repleased. Kind of like speaker wires. Ever heard a sound on say the pass-side front axcle, rip it a part to find nothing. Pull the other side and find the problem. The sound started on the driver wheel but travled to the Pass-side before creating the sound we hear.

Make any since??

[4kQuad]

so it's been a number of days now.......Whats up with the car???

[Toyguyz]

Right tensioner had a broken piece and the intake cam sprocket had tooth wear. The shop replaced the gears and installed a new timing chain set, (no charge to me!). We picked it up from the garage tonight and no more rattling noise.

My son has it out test driving it as I type, (it's his car now).

[4kQuad]

Cool, glad it was Free. Lucky kid, hope he has good luck with it.

[Brad97GS]

Interesting....I was thinking along the same lines as 4kQuad...but at least they figured it out rather quickly (and for free). :)

[Toyguyz]

Hey Brad,
I was beginning to wonder if you still posted on this board...

The conclusion was that either the guide was faulty or was cracked during installation and allowed the chain to slacken causing wear on some of the sprocket teeth and subsequently it was enough to cause the rattle noted. When the steering wheel was turned it varied the amount of torque being applied to the pulley which in turn varied the severity of the rattle.

Since he rebuilt the motor in Jan, he stood behind his work and fixed it for free. (not many shops do that anymore)

As for a vibration traveling through a rubber belt from the pump to the pulley on the cam, I must admit that I was struggling with that one. (The pulleys didn't vibrate or move at all when the engine was running and rubber really insulates vibration noise very well.)

Thanks for the inputs!

[4kQuad]

I was thinking that the power stearing pump was being ran off the shaft..Doh...That's what the belt does...spin the power steering unit.

:(

[p8ntman442]

my guess is that the timing chain was not installed in the proper manner allowing for very little, (but enough) slack between the cam gears, which caused the rattle untill the engine was under slight load from the power steering unit. this slack also could have damaged the gears and guides. Look to mechanic's error for this one and thank god they fixed it at no charge.

[Toyguyz]

Hey P8,
Good guess, a little late but good anyway. Tell me what your first clue was, a previous post maybe or were you just waiting to see if we could figure it out ourselves?

As for the mechanic, there was no hesitation on his part regarding diagnosing the problem and standing behind his work. (Most shops would have blamed a faulty component rather so they could charge at least labor for their time.) I'm real happy with this local shop and will send him more work in the future.

4KQuad,
Thanks for at least taking a shot at it before it was actually diagnosed. If nothing else it got us thinking before the tear down and got us to look a little harder at the gear teeth when it was torn down.

[fbod383]

Hey its the cam sprockets.. ahem.... :D Same thing happned to me.. got worse when I removed the PS alltogethor. then it started to shuck chains.. I was baffled.. sprockets looked good.. until I compared them to some new ones :rolleyes: