I'm going tonight to get all new vacuum hoses, actually I think there will only be one. I'm capping all of the ports except the one on the passenger side of the carb, which will go to the advance on the distributor. I took the trans spark gadget off and put it in a cabinet with all of the other parts that I've replaced, so that will eliminate a couple of lines and the thermo vacuum "tree" is all being capped off, so I think that will only leave me with one, since I don't use the factory ram air system, right now. That will hopefully go back on in the spring, once I get everything cleaned up.
Don't forget to re-connect the hose that goes to your heater/defroster controls and the power brake booster. :bglasses:
As a word to the wise, I suggest trying this... remove one spark plug wire at a time, from the distributor cap. This will reduce the possibility of your getting shocked. Note which cylinders respond with a reduced idle speed, and a definite miss. Note which cylinders respond with no change. If you have more than one with no change, note the pattern. It will tell you where to go next. Example: If the two adjacent cylinders are the problem, say cylinders 3,5, they may be switched either at the cap or on the plug. If cylinders 3 and six are non-responsive, they might be reversed at the cap. Note the firing order 18436572. 3,6 are adjacent on the cap, and the source of the problem could be there. If you come up with a difficult problem, such as 1,4 6,7, it could be that one side of the carb is not feeding fuel, as in a plugged passage in the carb. If you are unsure of where to turn, let us know what pattern you have and we can address it as it comes. Ray
I'll check those patterns in the next couple of days and see what I come up with. I am still very puzzled about the vacuum leak too, I found that I had forgotten to screw in the steel line that goes to the brake booster and it ran a bit better, but I can still hear a hiss around the rear of the intake. To me, it sounds like a hiss going into the carb, which it has always had, but it seems louder now. I blocked all of the vacuum ports on the motor, the three on the thermo vac gadget, and the one on the drivers side of the carb. The only port that is still open is the port on the front of the carb, on the passengers side. I have that one running straight to the vacuum advance on the distributor. I put my finger over this port to make sure that there was vacuum, and noticed that it is different than it used to be. Now, the vacuum isn't constant, it chugs along with the RPM of the motor. Is it supposed to do that? When I opened the door in the distributor cap, I could actually see the advance mechanism, bouncing back and forth with the timing of the vacuum surges. It's like some is turning the vacuum off and on very quickly. Any ideas on what might cause that? I have been putting off buying a compression checker and vacuum checker, as we just bought a new home, but it looks like I might have to bite the bullet and get them tomorrow.
Sounds like a valve problem to me...........perhaps a stuck intake valve, somehow the compression or exhaust is blowing back out into the intake............this sounds very serious, it could also be a broken intake valve spring or even a screwed up intake gasket. The only way to be sure is through careful diagnosis, and definitely do that compression test first to eliminate the valves as the cause. :bglasses:
To locate the source of the hiss, try this; using a vacuum hose of sufficient length, put one end in your ear. Not all the way, but far enough to where you can hear what is on the other end. Then, while observing the location of the free end, move it around the suspected area of the leak. It will be the loudest at the location of the leak. This may help more than the tried and true spray, which can go everywhere, confusing the issue. This also works when trying to lacate a leaking weatherstrip. Turn the key on, set the blower to high speeds and listen. Move the free end around the weatherstrip, and the leak will be very close to where the noise os the loudest.
Well, where do I start with the bad news? I did a spark test on all cylinders and they all seem to be firing correctly, so I moved on to the compression test. This is where my mood went downhill. I only tested one side of the engine, 1,3,5, and 7, and here's the results: #7 - 150 PSI #5 - 140 PSI #3 - 130 PSI #1 - 0 PSI Yes, that reads 0 (as in zero!!) I put my finger in the hole and had a friend crank the engine and I could not even feel anything trying to push my finger out of the hole. I thought that it was pretty much worthless to try it, but for the heck of it, I put some oil in the hole and tried the test and again, and still got nothing. I'm guessing that means that I have a totally blown set of rings? Or maybe even a toasted cylinder? I looked at the cylinder wall when I had the head off and didn't see any signs of a ring dragging on the walls, or anything else scraping the walls. This was the cylinder that had the bend pushrod that I had to replace. But before that I know it had compression, as I took that plug out first and ran the timing mark around the 0 and felt it with my finger. Don't where I should go from here with it, the engine stand, I'm guessing. :ball:
Time to pull the heads! A collapsed lifter would do the opposite of a stuck open valve. It would leave the valve closed at all times. (I'm pretty sure anyway, since there is no pressure on the pushrod to get the rocker to open the valve) I'm guessing burnt/stuck exhaust valve. Any bets?:grin:
Well, I can only hope it's a valve. Come to think of it, it was the exhaust valve that had the bent pushrod. Hmm...
My bet is that the guide clearance was too tight and the exhaust valve hung up and got whacked by the piston and bent the valve causing it not to seat...........the reason for no compression. I'll give you some very good advice, send BOTH heads off to a machine shop that can spell Buick and get them done right. Consider yourself lucky it did not damage the piston..........I'd check it very carefully. :bglasses:
I just told my fiance that if it had to have another valve job, I didn't want to have it done, unless the person knew the ins and outs of Buicks. She didn't understand why I won't take them to the local machine shop. o No: I had to explain that we had them done locally before and the shop gave us a set of normal heads back. I didn't think that they looked right when we got them back, and my dad agreed. He took them back to the shop and they swore up and down that they were the same heads that we took in. My dad wouldn't let them stick it to him, and the owner finally "found" the correct Stage 1 heads that we took in. I wouldn't buy a quart of oil from them now, and that was 22 years ago when we had the issue with the heads. Any recommended places to contact about having the heads done?
This situation could go either way onm the valvel issue. The bent pushrod is the result of the lifter attempting to open the valve, and its refusal to open, or stay open. To my knowledge, these engines had enough clearance to prevent piston impact. A bent valve, with no compression would be pretty obvious. I suspect a sticking valve due to valve guide problems. I suggest asking around about a reputable shop. It is worth the postage if sending them to a good shop.
