Let me just open this up by saying this old girl does not like me. I got suckered into working on it, I have to fix 2 so called mechanics mistakes.

THis thing has leaks at both ends of the manifolds, valve covers leak, alleged rebuilt motor that blew a headgasket. Hack mechanic charges $1500 to do the headgasket, truck smokes and runs terribly. It came back with a Qjet on it, instad of the carter that was on it. The guy essentially ripped him off, he was taken to court, got off scott free. (He was not licensed or insured to do mechanicing work.) I did a compression check, the numbers were miserable. Hot, the highest was 125, lowest was 100, average was 110. I was expecting higher for an alleged $8000 high performance motor. (the guy is old, might have his facts backwards, he inhereted the truck from his brother) On a dead cold compression check, the numbers were 60-80# dry, 80-100 wet. I did a dry cold check on my 460 in the motor home with 92K on it and got 115-125# cold.

This is one of the first things that happened to me once I started doing tuneup stuff on the truck, after I gave up on making the turd run correctly as it sat.



I put on new plug wires because the old ones were burned by the headers and poor routing. I did not like the way the old ones were routed, so I yanked them all off, and started from scratch. I did not pay close attention, did not notice that the last novice mechanic who put the dizzy in, was too lazy to set it correctly, so he moved the wires one position instead of doing it right. After a few failed starts, I remebered that they were wrong, moved them, nothing happening still. I am running the throttle, and remote starter (from under the hood) and there is a loud boom, and a flash and burned hair smell. I bout fall off my stand to get away from the fire, my vision returns, I see that I am not on fire. I get in the cab, the backfire seemed to have cleared the flooded condition, the truck started.

I pull the spark plugs to see how poorly the engine is running, this little beauty caught my eye.



Do you rekon this is the piston hitting the top of the head, or the valve is hitting it.

Another thing that caught my attention is the rocker arm assembly



I dont think it is stock for this year truck. I looked in the 75 service manual, and the truck Haynes and Chilton manuals, see no notice on how to adjust, or any mention of any adjustability. The lifters are definatley hydraulic, they bleed down after 2 seconds or so, and the valve closes.

So, here are my questions.
1. The book says there is no adustability, only with .060 longer and shorter pushrods. This motor clearly has an adjustable rocker arm assembly. Will the hydrualic lifter make up for any mal-adjustment? The engine sounds like it has either major piston slap, or valve train noise. What years did this rocker arm setup come from?

2. After the motor was overheated, the truck now smokes like a freight train out of both sides of the exhaust (White). The sides of the cylinder walls do not look fresh, I see no cross hatching. Is it possible that the rings have mananged to glaze the side of the cylinder walls, and now the rings are not doing their job? There is alot of metal flake in the oil. Blowby is not too excessive with the PCV hooked up, but without it, it is pretty good.

3. Time to take the motor apart, re-ring it, and freshen up the fresh heads?

4. The engine will only pull 12-13 inches of vacuum, and it dips 1-2" or so. I have checked for vacuum leaks, found none except the carb in a couple of spots. I have adjusted the timing back to 10*, and set the dwell from .013 to factory .017, put in a higher heat range plug, and closed the gap back to .035. Do you suppose the smoking might be because there is an internal manifold vacuum leak? I pulled individual wires to see if the smoking is limited to one cylinder, it did not seem to help. The carb is a Qjet by the way.

Keep in mind this truck is not mine. The owner is on a fixed income, and cannot afford to put a billion dollars into a truck he can only get $1500 for. He already has $1900 into it from botched repairs from two other hack mechanics. I have to keep the cost down. If it was my truck, I would take the motor apart, re-ring it and have the valves redone, but I need a backyard dirty used car salesman mechanic dirty trick to get this thing to stop smoking. I got it to at least be driveable again, but the smoking has to stop.

ideas, comments?

 

don't really have any knowledge for you but be sure to post this in the engine forum also. If it was mine I would probably pull the heads and try to get a better idea of whats going on in there, and put valve seals in while I was at it, but it sounds like you want cheaper and easier.

 

I know this is basic and you probably have already been through this but you said the truck started right? Is there a knocking that is real strong sounding? I had a piston do the same crap to me a while back so it very well could be hitting the top like you said...oh btw man I am glad your okay, that fire could have done alot more damage to you then your hair. Sorry I dont have more input for you besides the piston.

 

I do not particularly care about cheap or easy, if the truck was mine, the motor would be apart already. My customer is a senior citizen who wants the truck to be fixed, but I dont want to dig too far into the truck for cost reasons. The heads have new silicone seals already installed.

The noise I hear is less of a knock, and more like lifter noise, or piston slap. I've pulled plug wires, the noise, nor the smoke goes away.

 

I'd first try to adjust the lifters to see if the noise stops, if it was me.......that mite be it....get them just quiet, then loosen them a tad ......it can't hurt, right?

 

They are hydraulic lifters, I cannot find the procedure on how to adjust the rocker arms in my truck manuals. I dont have anything that goes back to whatever era these things came from.

 

fuel pump essentric ? I've singed my hair too. I was wondering why my freind was slapping me upside my head.

 

Electric fuel pump.

 

bumpity bump bump

 

Update. I think the shortblock is fried. I tried doing a leakdown test on it, averaged 80% leakdown (20PSI) at TDC. I slowly rotate the piston down, I would hear a thunk, and have a sudden pressure on the ratchet. Leakdown goes from 80% to 30% at mid cylinder. I get air pressure coming out of the valve covers.

I also discovered that the Qjet was responsible for loosing 3" of vacuum. I put a factory holley ('79) on, now at idle it pulls 15" of vacuum.

The motor seems to falter around 3500-4000 RPM. It did before I was messing around with it, and its doing it now after all the work Ihave done. It was backfiring thru the carb alot under accelleration. The top of the distributor shaft seems to have excessive play, 1/16"+. Will this cause any of these symptoms?

 

Update thread.
https://www.ford-trucks.com/forums/8...ml#post6897367