Hi,

New on this forum and new to Subies.

 

Have a recently acquired 93 Loyale with 76K on the meter.

 

It had a major oil leak on the right head gasket, so I had it changed along with timing belts, pulleys, tensioner, etc. The compressions were like new.

 

I now have preignition pinging on the left bank only.

 

Resete the timing to 20 BTDC, new plugs, rotor , cap, good fuel....

 

It put an IR thermometer on both side exhaust down pipes and the left side in about 40 degrees cooler than the left..

I am stumped. It is not making any noise- like knocking or lash adjuster stuck.

 

It runs okay, but not very smooth accelerating, and slightly rough idle when warm.

 

If the belt on the left bank were off one notch, could it cause this, or would it run really lousy?

 

Thanks.

Check for vacuum leaks... Especially the intake manifold gasket on that side. You might also check the egr valve/system function too. Ide also recheck my plug gap and plug wires.

It's possible the timing belt could be off by a tooth. It's fairly easy to check though.

 

There is an outer cover on each side of the engine you can remove without taking anything else off. That will give you access to the cam sprockets.

 

Then crank the engine over by hand (22mm socket, IIRC), and make sure the dot on the cam is straight up/down when the three marks ( ||| ) show up on the flywheel on top of the engine. The two cam sprockets should be 180* from each other.

 

It should be pretty obvious if it's off by a tooth.

 

-Dave

It's possible the timing belt could be off by a tooth. It's fairly easy to check though.

 

There is an outer cover on each side of the engine you can remove without taking anything else off. That will give you access to the cam sprockets.

 

 

 

It should be pretty obvious if it's off by a tooth.

 

-Dave

 

 

I'll look at that tomorrow. I thought access would be restricted by the compressor, and alternator.

I'll look at that tomorrow. I thought access would be restricted by the compressor, and alternator.

 

The covers are easier to get to from the bottom, at least on the drivers side. Should only be four 10mm, bolts in each one IIRC.

 

-Dave

Pulled the left ( drivers) side cover. With the three III hash marks on the flywheel lined up with the little index on the bell housing, the mark on the cam gear is not at 12 O'clock. It is off maybe about 4 or 5 degrees toward the fender.

 

 

This might explain why the distributor timing was indicating at 23 BTC instead of 20. The distributor is geared to the left side cam isn't it?

 

This should also explain why the left bank is running 40 degrees colder than the right.

 

Anyway, I took it back to the shop that did all the work. The shop writer is a jerk and is disbelieving that the cam timing could be off. They have not looked at it yet.

 

Now, I am wondering... I drove it that way for about 300 miles. Could it have burned and exhaust valve that way?

Probably hasn't hurt anything, but if it has they should step up and take care of it.

The shop that did the job pulled the front end off and re-checked the belt timing. Before they buttoned it up, they called for me to come see it. It was correct. I guess the angle I was looking at the pulley made it look off to me.

But here is the thing. It was still pinging.

 

I picked it up this evening and no more pinging but man, is it doggy. Yep, you guessed it. They just retarded the timing to 17-18 degrees!

 

After I saw that, I decided to check a few more things. Compression on all cylinders was 174, 170, 173, 165. ( 1 thru 4) Cylinder head temps with the engine warmed up and running at idle are 172, 158, 177, 146 F.

 

I have not tried to do a leak down check yet, as I don't have a good regulator set up.

 

I am wondering... is there more than one way to install the pulley on the camshaft? If so, does it affect the cam timing?

 

I cannot think of any reason why all of a sudden the temps on the left bank of cylinders is low and the lower power and pinging.....