All the plugs are out during the check? Starter turning good?

What if you put all plugs in but one and comp checker in the last hole then fire it very briefly? That should give a good comp indication if there is any present.
Dual roller cam chain huh? Hmm possibly different cam with very late intake closing? This thing a real dog at low rpm?

 

Scott

 

Thanks for the ideas.

 

I read somewhere once that 90% of all carb problems are in the distributor. I'd check out the whole ignition system, especially since the timing marks are so far off on the 2 balancers...the timing being retarded from the get go will kill MPG.

 

Will do.
Makes sense to start with fixing the known fault (balancers).

Steve

 

Well not normally. I was just thinking if there is a valve sealing problem then you would see the PSI jump up quite a bit since with engine running briefly that a non sealing valve would have less time to leak down vs at cranking speed and give a higher reading.

The same could be said for leaky rings too, but I would expect you to be seeing blue smoke if the rings were that bad in addition to oily plugs.

Maybe double check the lash on the rockers you have now. If too tight they could be holding the exhaust valves open slightly.

There has to be some explanation to those low numbers (MPG and compression) and the appearance of the plugs. They don't seem to agree with each other.

 

Do you have the tools to do a leak down test?

That may give you a better picture.

 

I know. It's a real head scratcher!

 

I do have access to one. Thanks ddawson. I will get that balancer on and get it timed accurately first and see what that does for the car.

 

[QUOTE and said he timed it "by sound".

Steve[/QUOTE]

This could be the cause of poor milage....retarded timing will kill milage.

 

This could be the cause of poor milage....retarded timing will kill milage.[/QUOTE]

I truely hope that this is all it is.

 

Make sure after you set base timing correctly that you verify the vacuum advance is working, that will help mileage quite a bit. Is this car a stick or auto ?

 

It's an automatic.

Thanks C6.

Steve

 

This is NOT making sense at all!

Found this out with the cover removed..
When I rotate the engine to line up the timing marks.......


The distributor rotor is 180 degrees out from #1.


Now logic tells me there's no way an engine will run with the distributor 180 degrees out from it's "properly aligned" position. Yet this engine did.

The cam gear dowel is at 3 o'clock, which is correct for #1 TDC orientation.

The crankshaft keyways are at the correct 1 o'clock position for #1 TDC.

With the left valve cover removed, both #1 cylinder's valves are closed.

When I towed the car into the shop (because it would not start) and then went to pick it up after they got it running, they said I had the distributor positioned 180 degrees out. The shop put the distributor in this current pictured position....and it ran. WTF

What am I missing here?

Steve

 

The dots lining up is firing TDC for cylinder #6. Firing TDC for cylinder #1 is with the crank dot up and the cam dot up. It's a very common mistake that I've made also. Frustrating as hell when the engine won't start after a cam swap.

 

Although it's difficult to tell from the photo because it's off center, it appears to be off one tooth which would retard the cam about 16 degrees, causing a very late intake valve closing and low numbers on a compression test.

Also, the newer balancer is correct with the TDC mark 10 degrees CCW from the keyway slot. To be sure, find TDC with the piston stop method and know what you have.

To verify cam timing: Set the engine to TDC-overlap (in this case the #3 intake valve will be closed; otherwise it's open at TDC-firing), and compare the amount that the valves on the #1 cylinder are open. If you find that the exhaust valve is more open than the intake valve, you have a very retarded cam.

The orientation of the distributor, as shown, is correct if dot-to-dot on the timing set.

 

Dot to Dot on the cam gears is the norm from proper timing (some crank sprockets have other symbols for advancing or retarding the relationship to the cam but they also have multiple keyway slots then. Degreeing the cam is the only way to know if its timed absolute correct.).

Your distributor looks to be 180 out. Instead of pulling the distributor someone just clocked the wires around your cap 180 out to match the rotor position is my guess. I found a friends distributor off by like 1 -2 teeth on the cam and someone had clocked the wires one post over each on the cap to get it running rather than pull the distributor. It seems some folks cant get the oil pump pickup correct and wind up just dropping the distributor where it will mesh with the pump drive and cam gear. However in your case you just have to pull the dizzy and drop it back in 180 and then re-run your wires on the cap properly.

At TDC on compression stroke(with everything at least close to timed) your rotor should point to the number one cylinder and the number one post on the distributor cap.

This will fix your timing anomaly but NOT the low compression. Distributor timing has no effect on the mechanical relation ship of valve timing to piston position. That is done at the cam gears and you appear just fine there from what I see in the pic.

 

Hmm something funny going on there. check to see if #1 is on it's compression stroke. Pull valve cover and see that both valves are closed and the rockers are all the way up and you can move them about rather easily.
If this is the case then your dist is 180 out.

However if one of the valves is open on #1 (tight rocker and lower than the one next to it) then #6 is on it's compression stroke (take valve cover off to verify) and both it's valves should be closed. Then the dist is orientated correctly.
It should be dot to dot on #1 compression stroke and #1 TDC with most manufacturers, but manufacturers differ and some are with cam gear dot up instead of down.

If this cam timing is off by a tooth then that would explain your very low compression readings. It should also be lacking a lot of low end power as I mentioned before.
If off that little it will be hard to determine unless you do use the piston stop method or some way to determine the absolute TDC of #1 cylinder on the compression stroke.

 

You need to get all that straight before worrying about mileage, although that mess will screw up your mileage big time. I asked about stick vs auto earlier because I would suggest an overdrive trans swap to improve mileage also (once all this stuff is sorted out). Either a 200 4R or a 700R4 would make highway driving and fuel economy very enjoyable. What rear gear does your car have in it ? And I agree that the cam gear looks one tooth off to me, so I think you really need to degree that cam...

 

I see your logic zwede. That would put the distributor pointing to #1. However, the dowel pin on the camshaft end would then be at 9 o'clock. Now unless this cam is some exotic freak, I can see it.
But look what I'm going by:

The Bible:


And the Book sayeth...


Cam dowel at the 3 o'clock, with dots together, although pic shows a BB. No?

And the distributor points to #6 tower and it runs!