Join Our Ford Truck Forum Today

Document your Ford truck project here and inspire others! Login/Register to view the site with fewer ads.

i think im in trouble

yesterday i noticed that my truck(79 f-250 300 ci 2wd 4spd) decided that it wanted to start tappin when accelerating and now also intermittently burns oil(usually after it sits for an hr or 2 and it started back up) but only has done this twice and has gone away each time. but back to the tapping. i know that this truck has alot of miles on it roughly 182k and that its bound to need work. but this tapping basically sounds like its starving for oil however it comes and goes and isnt a steady tap its all over the place. according to my oil guage it has pressure,so i checked the oil level and its full. as for the intermittent oil burning the first thing that came thru my mind was the head gasket went (had that happen with my old dodge ram 50) but i didnt notice any "snot" in my oil. the oil is fresh probably only about 3 weeks old and get checked every other day and topped up as needed. its certainly on the top end of the engine both the burning oil and tapping happen whenever they want and is not a steady every time i run the truck thing. any ideas?? im confused on this. the tapping could be valves out of adjustment but wouldnt they tap no matter what? it doesnt tap when its under a light or "normal" load like just cruising at a steady say 40 mph or so. but when i leave a stop light or pull a hill thats when it starts and like i said before it isnt steady and doesnt do it all the time. it didnt do at all on my way to work and when i left work it didnt do it but about an hr or so after i left work i went to leave my friends house and then it decided to start acting up and then i went to the store and when i came out and went to leave it ran fine again. so im lost. any ideas or tips or anything would be greatly appreciated. thanks,bill
 
if it were a timing issue wouldnt the engine run rough as well?? its starts,idles and picks up just fine and runs pretty smooth. i guess ill just pull the head when i get a chance and have it cleaned,planed,fluxed,ported,and polished, and rebuilt. i was planning on eventually having this done anyways now it just gives me a good excuse to go thru with it :)
 
Last edited:

BuzzGun79

Nov.TOTM 2012 / 2012 TOTY
2,388
55
Some things to look for...with the engine warm and running pull the pcv valve..if you see smoke thats a bottom end ring possiblity...Tapping could be Lifter wear,bleeding down then pumpng back up,valve/head work as well..
 

Beach66Bum

Moderator
Top Poster Of Month
if it were a timing issue wouldnt the engine run rough as well?? its starts,idles and picks up just fine and runs pretty smooth. i guess ill just pull the head when i get a chance and have it cleaned,planed,fluxed,ported,and polished, and rebuilt. i was planning on eventually having this done anyways now it just gives me a good excuse to go thru with it :)

no, not if the timing was advanced only 3 to 5 degrees past factory spec's. Will start fine, idle fine, etc. but when you are going up a hill and you are applying more load, then it will shows signs of "knocking" .
 

Fellro

Moderator
Staff member
What Roy and I are thinking, if it ONLY happens under acceleration, is pinging. If the timing is too far advanced, it will cause it to ping, but run fine otherwise. It is possible the mechanical advance is stuck, or if the vacuum advance is either stuck or has a hole in the diaphragm, you would not notice it that much otherwise. Fuel with low octane in the heat can cause pinging with everything else set right.
 
i never thought about running a higher test fuel in it to see if it clears it up a bit. ill try that when i get paid. there are times that it taps,or pings or what ever you choose to call it really loud like its starving for oil and then other times its barely noticeable its really subtle. i used to have a 64 buick special with a 355 wildcat under the hood.(300 ci v8,4 bbl carb and 11:1 compression) all factory. and that thing had spark knock so bad that a full tank of 93 octane sunoco fuel with a bottle of 104 octane booster wouldnt even put a damper on it and i had it checked and everything was set up properly. but the spark knock my buick had and the tapping my truck does are totally different. my truck taps at about 1/2 the speed of the engine and it sounds more like the valves than it does spark knock. but then again im not a certified tech. i know how to keep them going and what not but i dont know all there is to know and im certainly not certified :)
 

Fellro

Moderator
Staff member
The accel only is the main tip. If it was valve or other mechanical issue, it should be there all the time. They don't stop making the noise, then when you gas it all of a sudden make it. If this were the case, you should be able to duplicate when sitting still. Try the better fuel and see how it goes. It is possible to be a bunch of carbon build up on the pistons igniting early too. Compression spark knock and preignition will sound different. My old 327 with 11:1 high domes sounded like a diesel on pump gas. I ran 76 cc heads instead of the 64 cc that the 11:1 rating is from.
 

jebadiah04

Rooster Snorkler
849
27
Things that come to my mind. Timing is advanced and your hearing pinging.
Bad gas...could cause pinging
Lifter not pumping up good. Can come and go.

Try some fuel treatment first

Sent from my mudwhistle via lemmiwinks.
 
update on the tapping and oil burning. the cause for the oil burning has been nailed. i gunked the engine and washed it at a carwash and after about 2 days i saw oil sitting around the #1 spark plug. i looked at the valve cover gasket and saw that its bulged out in the same spot. thatll be fixed tomorrow. the tapping has quieted down now. started buying gas from a different gas station and noticed it cleared things up a bit. but it still taps. its a valve tap that is constant. it can be heard if you're standing next to the truck with it running. but when inside if you can hear it at idle its very faint. and at a steady cruise its not really able to be heard over the road noise until its put under a load. but it has calmed down quite a bit. thanks for all of your help. i'll be asking for more of it here in a few mins on another forum. thanks again,bill
 

Ford Truck Articles

Top