NEW PROBLEM(S):

[VileZambonie]

Sounds like you crossed #5 and #7 wires.

[Stewart G Griffin]

Do you think maybe i'm getting crossfire?   i'll check the wiring order again, but seeing how i checked it twice when i put in new plugs a few months ago and it ran just great until one day a month ago.   And then, after that i rechecked the order.  These are Bosch wires, so maybe they are too efficient or something?

[123 pugsy]

I used Bosch wires before and they were garbage.( the set I got anyway) 

[frogman68]

Really off the wall

But have you checked the line for the vacuum gage esp were it goes thru the firewall?

How bout the timing ? and the timing chain to be sure it didnt slip a tooth (if the chain and gear our original it will have nylon on the cam gear)

[Stewart G Griffin]

Chapter 3:
The neurosis continues.........

What i would like to discuss now, after checking the ignition, is the idle mixture screws;  Let's say, after viewing the video and ASSuming it IS NOT a valvetrain related problem---we are also ASSuming it is a carb problem.  If, after refering to the video and assuming(only assuming)the above, would you assume it is a question/problem of leaness or richness?

1)Basically, i am trying to determine whether to turn the screws inwards or outwards depending on whether we are running rich or lean at idle.

2)Additional Note:  i am not assuming that the carb is ultimately the problem, it's just that right now after eliminating some of the other stuff, i would like to try one last thing with the carb.  So, for the purposes of the question, the carb IS the problem----for right now.

Chapter 3, pt.2:
New strategy

Recently Completed:
1)plugged all possible vacuum ports (at least all that i could see)on the carb with vacuum caps and then either capped or taped off all vaccum lines that are now detatched----this includes the line going to the brake booster.  Result----no real change except the engine now can idle at 600-700 rpm with out stalling out---somewhat.

Planned:
2) test all plug wires using the KD 2756 tool.
a)visually inspect all spark plugs.
Would oil on the plug wires ruin them?  Because there is quite a bit of oil on wires #5,7, and i think 3.

3) if no improvement, then experiment with the idle mixture screws on carb.

4) if no improvment, then do the pouring the stuff into the carb while on high-idle in order to get the valves unstuck;  i mean there must be a good reason why mechanics used to/still do this?
a) what should i use?

5) if no improvement, then compression check.
a) if there is a compression disparity, try to determine if it is the valves or rings. (which i have my doubts)
b) if nessesary, take off valve covers and turn engine over to visually see if the valves are making full travel and/or if the rockers are not tight enough.
c) how else to determine if the timing chain has slipped without taking the cover off?  Everything including the fan and shroud would have to be removed in order to take the cover off.

6) if it is determined that something in the valvetrain is causing the problem, then i will swap to the 305 that is sitting dormant in my garage and be done with the problem; This i know runs good.

[123 pugsy]

Chapter 3:
The neurosis continues.........

2) test all plug wires using the KD 2756 tool.
a)visually inspect all spark plugs.
Would oil on the plug wires ruin them?  Because there is quite a bit of oil on wires #5,7, and i think 3.

I made a comment about Bosch wires.
The reson for the comment was that the leaked oil MELTED the rubber boot material.
Fix your oil leaks and get some new wires would be a good place to go now.

As for setting your idle, don't assume anything.
There is a proper PROCEDURE for this. You don't try to make it leaner or richer, you set it up.
I'm sure you can find it in a book or online.

Pugsy

[Stewart G Griffin]

So, you're saying in your case the oil melted your wires?

[smitty77]

Get a good set of plug wires, and while you are replacing them do a compression check on every cylinder.  It's an easy step that will tell you at the very least if you have bad compression in a cylinder.  I'm no expert, but I think this could point to stuck or mis-timed valves???  I always heard that if a cylinder was "off" from the rest, put some oil in through the affected plug-hole and crank again.  If the compression comes up the rings are shot, if not then you have a valve problem.  If all values are good, then look at something else because the basic motor is good.  Someone with more smarts than me will know for sure.

Good luck, and congrats on completing the carb re-build.

[123 pugsy]

So, you're saying in your case the oil melted your wires?

I could crumble the boot rubber with my fingers.

[keller]

My truck was doing a very similar thing and it turned out to be the cam shaft lobes were almost round and not opening the valves. I would remove the valve covers and run it to see if all the valves are going up and down at the same rate. Good Luck

[406 Q-ship]

My truck was doing a very similar thing and it turned out to be the cam shaft lobes were almost round and not opening the valves. I would remove the valve covers and run it to see if all the valves are going up and down at the same rate. Good Luck

Ding ding ding we have a possible winner.  Sorry Stewert I just found your thread or I would have giving you help earlier.  The vacuum gauge is telling you what is up, if the gauge jumps as you describe then it is in the valve train.  You have a flat cam, bent valve or a broken valve spring, pull the valve covers and look for the unusual in the springs.  Have someone crank the engine over while you watch the rockers to see if anything looks wrong.  There is a possibility that a piece of carbon is causing a valve to hang open.  Once you go through the above and if you don't find anything do a compression test, it is not the distributor or the carb.

[Stewart G Griffin]

i was afraid of that.  And i will get into it whole-hog as i return to full time at work.

Did you see my video on the previous page?

One thing i don't understand is if it is the cam or valve guide(s), how could they wear out so fast?  The truck was running just fine and then one day this started happening.

i think i'm going to try the sea-foam thing and then if that does not solve it, i'll pull the covers and do compression etc.

Could a head gasket be causing this?

[frogman68]

i was afraid of that.  And i will get into it whole-hog as i return to full time at work.

Did you see my video on the previous page?

One thing i don't understand is if it is the cam or valve guide(s), how could they wear out so fast?  The truck was running just fine and then one day this started happening.

i think i'm going to try the sea-foam thing and then if that does not solve it, i'll pull the covers and do compression etc.

Could a head gasket be causing this?

Stewart

If oil was not getting to one lobe it will wear down very quickly..

[406 Q-ship]

Your right to think that a cam going flat would happen slowly but it will not have the miss until the valve stops coming off the valve seat, which would seem like a sudden occurance.  I doubt it is valve guides, it is going to be a flat cam, broken valve spring, bent valve, bent pushrod, or a piece of carbon on the valve seat causing the valve to not seat.

[Stewart G Griffin]

(unfavorable) UPDATE:


Let's just say that, if oil (not alot) and water (not vapor) is coming out of the tailpipes and the oil/choke light is coming on despite that fact that i checked the oil level and it was ok.  Also, the engine is running even rougher than before.

If, theoretically, the above things are happening, what do you think the problem might be?