Multi issue engine resolution path advice.

[Invectivus]

Long story short, i bought a running six and c4 out of a 66 mustang and put it into my 67. I test drove the 66 first and while it was a little gutless, it ran fine. It took me about a year (i think) to get the headers and exhaust installed and got it going a couple weeks ago and it's ... terrible.

The good: it starts fine, idles fine, choke seems in the ballpark. Adjusted the throttle linkage so floored the butterfly is (essentially) fully open.

The bad: it has a crazy valve clatter at idle/low speed until it warms up AND is driven a bit. Oil pressure guage shows around 1/4, 1/3 up from low, never really gets over that. Oil looks good and is at a proper level. It has less get up and go now, none unless I floor it, and when I do, there is a very worrisome cacophany that I THOUGHT was more valve/lifter clatter, but suspect it mught be knocking/pinging like crazy. I'm not experienced enough to discern the difference. I checked the timing with the light, and while it's hard to see the balancer mark, it bobs around 6, a bit above and a bit below. I'm not sure how stable it's supposed to be. Timing does not change when i unhook the vacuum advance line from the carb, not sure if it's supposed to or not (but suspect is is). As an aside, the C4 doesn't shift worth a darn, has clean fluid, and plenty of it.

I'm running 93 octane gas, new tank/fuel line, old fuel pump/carb line/filter.

I'm suspecting at the very least a vacuum problem. I have a vacuum guage and need to get in there to verify but i know it could be a hose leak, carb leak, or a carb calibration causing the issue so i'd like advice on what the order (and process) of checking should be.

I'm also concerned about the effect of the headers. I'd assume the decrease in back pressure would make the engine run rich, and I need to pull, and clean the plugs and track it, but i'm concerned to run it much at all until I verify i'm not blowing my engine apart with timing issues.

 

[Invectivus]

Oh, I meant to mention I want to change the oil here soon, but want to toss a cleaner in there to maybe lift any gunk and potentially open some pathways, and I wanted to straigten out my timing before running it enough to cycle it around the engine. I'm also happy to swap out remaining filters/lines, I just don't want to fall into the cycle of blindly replacing good parts trying to fix a problem that's a calibration issue.

 

[Explorer]

You do have different things going on, but first thing I would do is take your vacuum gauge and see how much manifold vac you have. Should be 17-21. Low vacuum will affect everything you posted except the valve clatter.

 

[rbohm]

8) first thing you want to do is make sure the engine has adequate oil pressure even when cold. and unfortunately the stock gauges are not accurate enough to let you know if you really do have an oil pressure issue or not. thus what you want to do is get a mechanical oil pressure gauge with actual numbers, and plumb it into the system and see what the oil pressure really is. you should have at least 20psi at idle, and about 10psi per 1000rpm above that. if the pressure is good, then it is possible that sludge is preventing oil from properly circulating. i would take a can of marvel mystery oil(aka auto trans fluid), and run it through the engine at idle for about 20 minutes, then change the oil and filter. that should clean out the sludge.

next i would go after your running issues. as indicated you may not have enough vacuum for a smooth running engine. if this is the case, replace the carb gasket, as well as the adapter gasket(many people forget this gasket and it will cause you no end of headaches if you dont replace it).

in dealing with your timing issue, your best bet is to power time the engine. add timing until you get detonation or spark knock under light acceleration, then back off until the detonation goes away. by the way you should be able to run 87 octane fuel.

as for the headers, they do not richen up an engine, they lean it out because of the better scavenging effect they create. if you have a rich mixture, then likely you have a carb issue as well.

 

[CZLN6]

Howdy Vick and all:

You've got some good start ideas already, but I've go to add my two cents. After a thorough check for vaccum leaks and eliminating them, Verify that your timing mark on the damper is at top dead center.

Next set the initial timing at 12 degrees advance. That is the stock setting for a 200 with a C4. Be sure to disconnect the vacuum line before setting and to reconnect it after setting.

With this much done and checked off, insect the inside of the distributor. Make sure there are two springs on top and that all is moved easily. Next start the engine and watch to see that the vacuum advance arm is moving as rpms rise about 1500 rpm. This is all to verify that the vacuum advance is working as designed. If you cannot see the arm from the diaphram to the distributor move something is wrong- either at the SCV on the carb, or with the vacuum cannister on the distributor.

If any, or all of the above need fixing/cleaning/or replacing do it.

The other issue that must be considered is that the inside of the engine is gunked! The Mystery Oil suggestion is a good one. It is a high detergent additive and will remove alot of gunk- but only if oil is able to flow through. If a line or oriface is plugged it cannot work. I'd suggest that you remove the valve cover and visually inspect the area. Look for broken springs, pieces of valve seals and other crud. Closely inspect the pushrod ball ends to verify that they are round and shiny. Inspect the rocker arm cups to see that they are smooth and shiny. If they are not, you've identified part of your problem. You will need to remove and disassemble the rocker arm shaft assembly for a complete cleaning. If all appears good reinstall everything, but leave the valve cover off. Start the engine and watch the rocker arms to see how long it takes for oil to begin seeping out of each. My guess is that one or more of the rockers is not oiling. Check it out and let us know.

Good luck

Adios, David

 

[Invectivus]

So i worked on the mustang to get away from work annoyances (yay work from home!) and i found a couple interesting things. Here's a pic of my carbie-

http://www.invectivus.com/fordsix/1940Carb.jpg

So, you can see my throttle linkage assembly, and just to the right and down is my single manifold vacuum line out to my C4 (which is shifting fine now with the tightening of the clamp). My manifold VAC is solidly between 15 and 20 on the guage, and only feeds the tranny.

Up from there is another hose angled to the lower right, that's the line to the rear of my valve cover.

Above that coming straight out is a bare fitting, this fitting shows vacuum under choke, nothing under warm idle, and ~ manifold vacuum under load. I get the feeling this one should be attached to my Dizzy.

what IS attached to my dizzy vac can is the upper black hose, to the left of my warm air tube going into my choke. This one shows Vac under choke, nothing under warm idle or power range. I don't know where it's supposed to go, but i don't think it's to my dizzy, and for the life of my i can't find any documents on the carbie connections. anyone have an idea?