oil light comes on, valves tap

[720tillidie]

Ok, its a Z24 in an 1985 720. The valves tap all the time, they never stop tapping. The oil light comes on when it tries to idle(like at a traffic light). Its always done this and I've been driving it for almost 3 years. I've adjusted the valves and no luck. The truck also shakes when it tries to idle but if you hold the pedal at a slightly higher idle it stops shaking and when its shaking that's the only time the oil light comes on. Highway speeds don't help the valve tap, when driving normal(45mph) I can't hear the valves but highway speeds they seem to "clatter". I belive all of this is tied together some how. Please give me feed back, I'm putting a lot of time into it lately(upper and lower ball joints, outer tie rods, new brakes front and back, lowered 2 inchs) and I want to put a weber in the mix but i want to figure out if I have serious problems with this valve tapping first.

[PEZi]

well i assume you know whether or not you have enough oil for one.... and if you do have enough... there is a chance you need a new oil pump

[720tillidie]

Yea it has plenty oil, it dosent burn any either. How hard is it to change the oil pump? Is it inside the oil pan and how sure are you that its the oil pump?

[PEZi]

how sure? not very.... but from the sounds of it... there is a lack of oil making it to the top of your engine which makes me believe its not getting pumped properly.... clogged maybe? possible need of an oil pump.... i can't be sure as of yet

as far as replacing... the process is not hard and i will post it up soon in the DIY section... but the funny part is that my manual doesn't say exactly where it is located... but i can tell you that you will not need to remove the pan

[720tillidie]

Any ideas on the shaking when it idles?

[Aven]

By shaking, do you mean that the truck idles rough, like its thinking about stalling on you?

[PEZi]

how hard is it shaking? light shaking may be from a bad air to fuel mixture.... all the way to terrible shaking caused by more awkward things....

mine once shook VERY hard.... it was because it was only running on 2 cylinders at idle... turned out to be a vacuum related issue

[MetalFab]

Another thought, how low is your idle set at? Sounds like a general tune would fix the idle issue. Try a good once over on the vac lines with carb cleaner, look for any change in idle.I've used engine treatment additives such as rislone, slick50, and marvel mystery oil in the past to cure knocking noises, clean oil passages, etc. Just remember to change the oil and filter + treatment within a few hundred miles to make sure your filter catches all the gunk. I still use marvel at every oil change. Might or might not work for your situation, but at least it's cheap.

[720tillidie]

It does seem like it does try to stall when the shaking starts, all the movement seems to be coming from the front of the truck so I'm positive its engine related. Remember the shaking only starts when the truck tries to idle, if I push the gas ever so slightly the shaking stops. My idle is set the same way from the factory. It almost seems like it isn't getting enough gas but I've also had vacuum line leaks problems but thought I fixed them all. I gotta figure this out, my truck sounds aweful. Could it be carb problems possibly? It seems like from reading about carbs hear at nico the head gasket blows shortly after installing the new weber carb in a few stories I've read so I'm kinda gun shy. By the way, thanks for the feedback from everyone, no one I know has a 720.

[dogred]

When was your last tune up? Pull your plugs and see if they are worn, then move onto the cap and rotor. Your oil pump is in the front of the engine diagnally across from the distributor. They are fun to replace since they are geared up to the crankshaft, but your tapping sounds like the topend is not getting enough oil. Did you do the valve lash while it was hot or cold? It is best to do while cold and the exhaust and intake are different sizes.

[720tillidie]

The engine was cold when I did the valves, I did them the way my haynes book said. My last tune up was in the last 2 years, I probaly have 20 to 25,000 miles on my last tune up. However I haven't replaced the ign. Coils yet. When you say "fun" I'm guessing its goin to be hell changing the oil pump correct? How often do you give your truck a tune up, personally I mean?

[PEZi]

It seems like from reading about carbs hear at nico the head gasket blows shortly after installing the new weber carb in a few stories I've read so I'm kinda gun shy.

i have the biggest downdraft weber available for our truck.... my headgasket is just fine keep the coolant system working to the best of its ability and you should be fine

weber + un-maintained cooling system = blown headgasket

remember... i race mine... i punish it pretty bad... and even with the beastly carb i have on it i haven't had even a rumor of an issue

[720tillidie]

That's awesome news. I saw your video on youtube by the way, all I can say is .... envy. It sounds damn good too. So let me ask you this, how different is the gas mileage going to be between using a 32/36 and a 34/34? Is the 34/34 going to use way more gas than a 32/36 in a daily driving aspect? The 34/34 is cheaper but will the extra consumption kill my mileage?

[Aven]

I'd start with your vac lines. I was having the same basic problem. It was idling really rough and sometimes quit if I didn't put it in neutral and give it gas.

I caused my own headache. I started replacing mine and didn't draw out a diagram them or mark them. I jacked something up following the diagram. Couldn't figure it out. Ended up pulling everything but the one from the distributor and capping the rest.

[PEZi]

That's awesome news. I saw your video on youtube by the way, all I can say is .... envy. It sounds damn good too. So let me ask you this, how different is the gas mileage going to be between using a 32/36 and a 34/34? Is the 34/34 going to use way more gas than a 32/36 in a daily driving aspect? The 34/34 is cheaper but will the extra consumption kill my mileage?

the 32/36 will get better mileage than the 34/34 for sure... but will the 34 'kill' the mileage? not necessarily.... the 38/38 does tho that's what i have.... 38 DGES

and as far as the video goes... that is OLD! i should be taking some much better videos with all my new mods and my new tire setup and stuff on the 27th (weather dependent)... once i get those up that old video will look terribly slow

[720tillidie]

I have got to see that when u get it up. I bet you get killer power from that 38. I think I might get the 34 after I get the tapping taken care of.

[flinterman2000]

Try flushing the engine like moredunes said, before pulling the oil pump. Remember to change the filter again after about 4 to 500 miles after the flush. The pump itself isn't hard to change and its done outside the engine. Lower left front when watching from the front of the truck.