[goat2789]

Lost my thrust bearing so changed rod and main bearings. Now the motor runs very rough. I have spark to all but you can pull plug wire 1 and the idle does not change. there are a couple of others you can pull and idle does not change. The engine will idle fine with base timing at about 25 degrees. Runs bad at 6 degrees. I checked and #1 has compression and i relashed rockers to 1 turn. Any suggestions?
MSD distributer
MSd 6al

[gtofreek]

How are you checking for spark. I do it with the plug wire hooked up and use the inductive pickup on a timing like to check for spark. If you have a bad plug, the wire will spark if pulled off the plug but will not if left hooked up to a bad spark plug. Just changing the bearings would not do anything to effect just one, two or three cylinders. The timing chain marks look correct. If the cylinder has good compression, the only other things you need to make it run is spark and gas. If you have them, I would change the spark plugs. Don't use Champion plugs. I have had many be bad right out of the box. I prefer Autolite the best. They always work good.

[goat2789]

thanks for the reply. i checked spark with my timing light and even swaped a couple plugs with no change. The timing thing bothers me so i am degreeing the cam. i degreed the cam in january on its install and worked out on the zero degree strait up marks. Now strait up comes up at 113 and ahead 1 tooth gives 128 and back a tooth from strait up works out to 95.5. What could have changed? ran fine 2 weeks ago strait up.

[gtofreek]

Cam timing would affect all cylinders. It would make very low compression if it was retarded or bend valves if it was too far advanced or retarded too. Is the compression even all the way around? Or is it low on some and not others. What is the compression coming out at?

[goat2789]

i will do a compression check, yesturday i took number 1 plug out and turned motor over a couple of times and got 150 lbs.

[lust4speed]

Most every engine idles better around 25°, but starting issues and total advance require the timing to be set lower to avoid problems. What all did you remove from the engine? Did you remove the heads, intake manifold, or distributor? One turn should be fine on the rockers, but you might drop down to 3/4 or 1/2 a turn and see if there is any change in idle.

...I do it with the plug wire hooked up and use the inductive pickup on a timing like to check for spark. If you have a bad plug, the wire will spark if pulled off the plug but will not if left hooked up to a bad spark plug.

This is also my favorite method, and if it passes you are pretty well assured that it isn't a spark problem. It could still be swapped wires or something else not directly related to spark.

[goat2789]

did the compression check and here are the results. wierd thing is 1 and 3 had 215 lbs at first, on second try back to normal. i would bet # 7 on a redue would be lower.
1-180 2-175
3-185 4-175
5-180 6-185
7-205 8-180
The engine was totally dissembled and flushed so cam was out.
These readings are the same (except for #7) as when i installed the cam and heads in january. I have had nothing but trouble with these comp roller lifters since installed. could they be the problem?

[gtofreek]

If the lifters are bled down[valves were open when engine was last shut off] then they would have made the cam seem shorter on duration until they pumped up, which would have made the compression go up. The compression otherwise seems pretty good except for #7 being 205. That could happen from a cam going away, but that would be kinda rare on a roller cam. Now, if it was a cast cam core, and not a billet, it is a lot more common for them to wear trenches in the lobe. That would make the compression go up, as it would be closing the intake valve sooner. Try running the engine and do a compression check on #7 right after you shut it off, and see if it changes. You should only have to run it for a few seconds, just long enough to get the lifter filled up with oil.

[HWYSTR455]

What kind of plug wires are you using, and how old are they? Check resistence on the plug wires, make sure none are bad. Taking them off and putting them on can break a conductor inside, bending them too much can as well.

Also, make sure the cap is on the dizzy tight, correctly, and check it for arc/wear.

Does that cam gear have 2 marks on it? Can't tell if it's my eyes or the pic...

.

[goat2789]

msd wires are a few years old. tonight we eliminated the 6al box, swapped #1 plug wire with a spare, swapped plug #1 with #3. number 1 still will not fire correctly. the car idles better after running for about 30 minutes. here are the temp readings on the header pipe.
1-130 2-260
3-340 4-165
5-210 6-165
7-172 8-215

number 1 intake and exhaust are now set at 1/4 turn past zero lash.

[HWYSTR455]

That narrowed it down some. What's the cap & rotor look like?

,

[goat2789]

The terminals were cleaned last week. Cap and rotor look good. Could it be a vacuum leak under the intake. I sprayed brake clean around the intake with no rpm change. Also I did not install the exhaust crossover blocking gasket because kre heads don't have the ports.

[gtofreek]

I was just going to mention a vacuum leak. If not the intake manifold, check the intake runners to those cylinders to see if there is a vacuum fitting in them and check whatever those vacuum hoses go to. You may have a leaking brake vacuum booster, or something like that.

[Stuckinda60s]

Verify TDC, it sounds like your distributor is 180-degrees out. I know a lot of guys will say an engine won't run that way, but I know that's not true.

[gtofreek]

The engine WILL NOT RUN with the timing 180° out. Who ever told you they would, obviously does not understand how an engine works. Also, the mis is in one or two cylinders, not all of them.

[Stuckinda60s]

Originally Posted by gtofreek

The engine WILL NOT RUN with the timing 180° out. Who ever told you they would, obviously does not understand how an engine works. Also, the mis is in one or two cylinders, not all of them.

I've seen it happen. It ran terrible, but it ran. The distributor had to be moved quite a bit from the normal timing, it started, with difficulty, but it ran. It's a simple thing to check.

[goat2789]

I did rotate distributer 180 degrees. It poped back through carb and would not run. Tdc was verified.

[lust4speed]

I enlarged the image of the timing chain and everything looks good. The 0 mark on the gear teeth would align with just a slight turn of the crank, and the keyway is in the crank gear 0 slot. Ignore the blue line being too long and going down so far. After posting I noticed that it could imply a relationship with the #2 slot, but it doesn't.

[goat2789]

I removed the intake tonight and there is oil in some of the ports. Is there any other way other than the pvc valve to get oil up there. There doesn't appear to be any blow by and no smoke out the tail pipes. What could be wrong?

[gtofreek]

Does your PCV valve hook up to that intake runner? If so, you need to relocate it to the base of the carb and not an individual runner. The PCV system is really the only way your going to get oil that far up the runner unless your engine was pumping serious oil past the rings and your cam had a ton of duration. Since you have no exhaust smoke, I would say that is not the case. If it were a Chevy or Ford, it could suck oil from the lifter valley, past the intake gasket. Pontiac was smart about this though so that is just not a possibility on them.

Does your PCV valve go into an original type valley pan? Or is it an aftermarket stamped aluminum pan? Or does the PCV go into a grommet in the valve cover? If it goes into the valve cover or a stamped aluminum valley pan, then it needs a good baffle installed. I have not seen a good one yet for the stamped aluminum valley pans.