Clunking noise when accelerating

[TominMO]

Filled the tranny with motorcycle synthetic 20W50, no change in clunking sound. I recall when I took Matthew apart, the rear tranny mount was toast, but there were no symptoms of that. So now I'm leaning towards a lower-end issue, like 2jzkilla said. Maybe a con rod bearing going out? Does this seem like a possibility? I had an MGA a long time ago, and had the same kind of clunking sound going on for a brief time (like minutes). But it was continuous, not just when accelerating. Then I heard an explosion, and found a hole in my block you could put your fist thru. In retrospect, I think that was a lower bearing giving out.

I'm having Matt D. build me a head for this motor, but sure would hate to find out the bottom end is toast. If so, I'm hoping (and expecting) he could rebuild it better than new--but major $$ involved. :-( For now, I could stick Matthew's motor into the Festy instead of the Aspire, which runs fine. Number of miles on the B6 is unknown.

I might be in the market for a good gen2 SOHC B6 block....

[TominMO]

Gonna look at my tranny fluid tmw. I've got ATF in there, and noticed it's leaking out of both of the driveshaft seals. Might be low, and that also might account for the clunking. Seems a lot more likely than loose inner tie rods causing it. Will switch to 20W50 motorcycle oil (like Charlie uses), which will slow down or stop the leakage due to being much thicker; and being motorcycle oil, it has all sorts of good gear additives. This is what I was running in Matthew's tranny.

Plus I'm ordering new inner tie rods for both cars.

[TominMO]

Checked out both the Festy and Aspire today. On both cars, everything seems fine as far as rubber boot integrity/no grease showing, on the LCA and tie rod ends (I replaced the tie rod ends and steering boots when I bought the cars). Pinch bolts seemed to be doing their job. Front sway bar mounts are on tight. Festy engine mounts seemed to be fine as far as I could tell.

However, after lifting the tire off the ground, when I grabbed it at 9 and 3 and wiggled it, on both cars the driver's side moved. So probably inner tie rod, possibly rack. On the pass. side, the Festy seemed pretty tight but the Aspire was loose. On both cars, the driver's side was worse. The Aspire has ~183K miles, the Festy has much less, and was mostly an RV tow car. All inner tie rods (and the racks) are original AFAIK.

Interestingly, if anything the Aspire seemed to be worse, since it was loose on both sides. But I just drove 2400 hwy miles in it and it seemed good, no noise at all and steered fine.

[TominMO]

When mine was doing something similar, it was because the lower rad support had rusted through and caused the engine carriage to drop on the sway bar. It probably isn't your issue but worth a check

This car is pretty rust-free, esp. in front. But one more thing to be aware of, true.

Don't know about automatic transmission but with a manual you can let out the clutch in forward and reverse and listen for engine mounts. When my control arm pinch bolt nut loosened the knock was on bumps not acceleration or deceleration.

I'll look into that. I do know that all my pinch bolts are there and tight, on both cars. But the bolts may be worn where they contact the ball joint indent. I think on the Aspire it may be a ball joint/pinch bolt issue. But I'll go thru everything suspension and steering related on both cars.

[WmWatt]

Don't know about automatic transmission but with a manual you can let out the clutch in forward and reverse and listen for engine mounts. When my control arm pinch bolt nut loosened the knock was on bumps not acceleration or decelleration.

[TWFodor]

When mine was doing something similar, it was because the lower rad support had rusted through and caused the engine carriage to drop on the sway bar. It probably isn't your issue but worth a check

[TominMO]

Tom I heard the clunk just once when first taking off and while pulling into the parking lot that's why I said rack or ball joints .
What you are Describing sounds almost like axels? But I've never had an axle clunk on anything but turns

Right, I discounted axles for the same reason. Plus, all axle boots are in good shape, so no grease leakage or dirt getting in. Axles were new when Greg did the motor swap ~5 years ago, and the Festy is only one of several cars I drive.

I could believe worn ball joints or the bolts that hold them in. But my LCA boots are in good shape, as are the tie rod end boots. I'll know more tmw.

[william]

Tom I heard the clunk just once when first taking off and while pulling into the parking lot that's why I said rack or ball joints .
What you are Describing sounds almost like axels? But I've never had an axle clunk on anything but turns

[TominMO]

Sounds like mains to me. Or connecting rod.

Seriously doubt that.

[2jzkilla]

Sounds like mains to me. Or connecting rod.

[TominMO]

Is it just 1 clunk or or is it hammering with the speed of the engine?

Turn the wheel all the way to the right and reach down on the passenger side and see if you can get any play up and down under the boot. If it isn't shredded. It takes some muscle. If there is play more then just a tiny wiggle it's probably getting bad. Even if there's no play could also be inner tie rods.

It clunks continuously when accelerating, stops when I let off the gas. I'll look around tmw and report back. In fact I get similar symptoms with my Aspire, which is now in the garage for other stuff, so I'll look at that one too.

[2jzkilla]

Is it just 1 clunk or or is it hammering with the speed of the engine?

Turn the wheel all the way to the right and reach down on the passenger side and see if you can get any play up and down under the boot. If it isn't shredded. It takes some muscle. If there is play more then just a tiny wiggle it's probably getting bad. Even if there's no play could also be inner tie rods.

[TominMO]

All this stuff is pretty easy to check out; but what is the symptom of worn rack bushings, when I am in the wheel well looking around?

[TominMO]

I heard that when you gave me a ride. I thought ball joints/pinch bolts or worn rack.

I'll check that stuff out too.

[william]

I heard that when you gave me a ride . I thought ball joints/pinch bolts or worn rack.