Gaba wrote:

well opened up the valve covers yesterday "hoping" to find a bent push rod or a rocker off the valve stem ( happened before twice) , or anything obvious.. that was a negative . i should be happy but I am not LOL cause this is a gremlin.. LOL

Now that the valve covers are off .. I will figure out true TDC on the piston first, mark it, then see if at TDC both valves are closed and not opening prematrely or too late..

Also I somehow will check if all the valves are moving up and down and none is barely moving (should I crank the motor with the starter for that..? or hand? cranking with a starter may make a bit of an oily mess .... right?

i dont suggest crank with starter
remove the sparks plug and crank manually to see the exaust valve coming up piston nr 1  .
is a very little move when you are at cams summit . If i remember should be the first vave if you look in front
when you find the valve close and you turn again a little you will see the exaust valve start open ( means you are little after)
Look at mark on balancer and you will see is around tdc.-
insert the distrbutor and good luck !
 

TKOPerformance wrote:

I agree with. Alessandro, check everything. by cranking by hand.  The problem you're going to have is that with. hydraulic lifters you aren't going to get good measurements because the lifters will just pump down.  To really check the cam you need to put a solid lifter in and check it one lobe at a time, or put a set of solids in it.  Its a bummer, but its the only way to get reliable measurements. 

I'm sure you know this too, but just in case; you can't check TDC based on valve position.  The valves are often opening or closing prior to or after TDC for various reasons owing. to the cam grind.  With heads on a screw in piston stop using the spark plug hole is your only real option. 

well as far as removing the lifters for now, i am not going that far into it as I dont see a need YET. I could be wrong..

I will spin things with hand

and yes I agree with you on the TDC position. I will be eliminating valve / cam / timing chain from the equation by doing TDC using a piston stop, and marking true TDC on harmonic balancer first, and then seeing where the valves are at that TDC.

Thats my next thing to confirm all is good. I will restab the distributor at that TDC mark and advnace 10degrees from there.

even with spark plugs off, the engine is harder to spin .. is that because of the three belts (alt, PS, AC..? )
 

thats it.. spin one way the engine will stop at one point, mark on harmonic balancer
go the other way ( opposite) and the piston stop will stop the piston on a different location close to the other mark.. mid point of those two points on the harmonic balancer  is the true TDC

Michael H. wrote:

So, you're saying it doesn't matter whether or not the piston is at the full height of it's travel since it will be stopped at the same point both times?

Yes same spot same height down from its top point ... just two different marks on the harmonic balancer

MachTJ wrote:

I still put money on the distributor being the problem, unless when you checked the roll pin on the distributor gear you can see light through it. I have had the roll pin look like it was intact but infact it was broken into 3 pieces. The sudden drivability issue after mashing the throttle is the key here. Yea a timing chain could jump but its so very unlikely unless there are one of those cheap single roller chains with the plastic teeth on the gears (still highly unlikely). If there is nothing laying loose after pulling valve covers, you would notice a catastrophic break which would cause issues.

ps was it mentioned whether it was point ignition or electronic?

I took off the roll pins all the way out and reinstalled . so pins are confirmed good

MSD ignition, spun the distributor by hand when it was out connected to the MsD , and there was tons of spark from the coil .. red got spark.

I am definitely going to restab the distributor , illl let you all know

josh-kebob wrote:

harmonic balancer....rubber dried up/cracked and the bond released, then the outer ring spin....

Harmonic balancer was changed 5 years ago .. old one had that issue

Gaba wrote:

TKOPerformance wrote:

I agree with. Alessandro, check everything. by cranking by hand.  The problem you're going to have is that with. hydraulic lifters you aren't going to get good measurements because the lifters will just pump down.  To really check the cam you need to put a solid lifter in and check it one lobe at a time, or put a set of solids in it.  Its a bummer, but its the only way to get reliable measurements. 

I'm sure you know this too, but just in case; you can't check TDC based on valve position.  The valves are often opening or closing prior to or after TDC for various reasons owing. to the cam grind.  With heads on a screw in piston stop using the spark plug hole is your only real option. 

well as far as removing the lifters for now, i am not going that far into it as I dont see a need YET. I could be wrong..

I will spin things with hand

and yes I agree with you on the TDC position. I will be eliminating valve / cam / timing chain from the equation by doing TDC using a piston stop, and marking true TDC on harmonic balancer first, and then seeing where the valves are at that TDC.

Thats my next thing to confirm all is good. I will restab the distributor at that TDC mark and advnace 10degrees from there.

even with spark plugs off, the engine is harder to spin .. is that because of the three belts (alt, PS, AC..? )
 

yes its hard to spin also with a wrench . Not only for belts , also all the inside mechanics engine parts.
The suggestion about valve position is only for you to be sure to start from a sure point , after that you can flag it and pass on something else like ignition or barrel float level that could be stopped on close position . 
 

I vote timing chain ONLY because  my boy was having an issue similar to this and it was a slipped chain (MAJOR slip!)
Crank engine over...with starter...coil wire OFF. Put your hand over the top of carb and feel if you have strong vacuum OR does it want to blow your hand back off? ex...suck-blow-suck-blow
6s6

Marco wrote:

Gaba, did you check compression for each cylinder?
Marco

Yes here are the numbers

#1 —155
#2 —155
#3 —165
#4 — 180
#5 —155
#6 — 165
#7 —175
#8 —150

6sally6 wrote:

I vote timing chain ONLY because  my boy was having an issue similar to this and it was a slipped chain (MAJOR slip!)
Crank engine over...with starter...coil wire OFF. Put your hand over the top of carb and feel if you have strong vacuum OR does it want to blow your hand back off? ex...suck-blow-suck-blow
6s6

That was a great idea to check ... I did that test.. plugs were in , had wife crank the starter while I put my hand over the carb , and all there was, was suction , no blow action at all! ... which means no valve timing issue

So... next thing is distributor check. Left the distributor in as where I stabbed it , so when I determine true tdc at compression, I can see how far off I was

Will keep y’all updated

6sally6 wrote:

Just an FYI for us.........how old is the engine?
                                      chain ever been replaced?
                                      what kind of work HAS been done on engine?
hang in there, you'll/we'll get it
6s6

Have I replaced the chain ..? No

How old is the engine.. no idea came with the car .. supposedly rebuilt 3000 miles ago... I don’t believe it .. oh well

.040 over, I know that

Heads were redone 5 years ago when I lost #4 exhaust valve.. since then I have again lost that same valve once when the rocker arm slipped off the valve stem, and bent the push rod . At that point I replaced the push rod and rocker. This was over 2 years ago!
But yes , we’ll figure it out

Last edited by Gaba (9/30/2018 9:59 PM)

Alright I got some answers

1) no movement lag in distributor when  moving engine clockwise and anti clockwise, no noises . All smooth movements and no slop

2) did the TDC thing , and found out that my “0” mark was way off.. thanks TKO , MS , and everyone else who insisted I do this. Now I have new markings to go by, had the right tape to stick on the correct TDC..

3) the distributor was not 180 off, infact was at 0 mark perfectly at TdC compression.

4) don’t think chain has slipped , watch this video

https://youtu.be/Z4F5EUbnSXU

I’ll make a video on both sides and post , so we can all look at it

Next step after that will be put back the valve covers ,

Then a fuel pressure test .

After that, fire up , and let’s see where we are at