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What happened?

Makedust

Makedust

New Member
I have this 70 with a 302 2v (original) rebuilt about a year ago.
It's been running (no T stat) and driving great for about a year.
Everything is stock.
After installing a new set of plug wires (just because my son wanted blue ones) and a slight adjustment on the distributor I took it for a drive and it ran a little hot.
I parked it, and took it for another drive after about 20 minutes and my #8 exhaust rocker came loose.
Torqued rocker, installed fan shroud, and took it for another drive.
It ran great but when I parked it it started puking coolant.
I did hear the valve train as I was parking so I'm going to say it was getting pretty hot.
Never had any problems with it til about the middle of last week.
 
While it may be just coincidence, the old service tech in me is screaming if it "broke" right after you worked on it...it didn't break. It's something you did. But then you did say in the last sentence " never problems until last week". So what is it? Need to nail down the facts before you start diagnosing the problem/cause.

Your slight adjustment on the distributor wouldn't have been to advance the timing would it? Timing can cause an engine to run hotter.
 
It did not sound as good as it did a few weeks ago so that's when I fiddled with the timing and installed the new wires.

I knew that the timing was part of the overheating so I double checked it, and adjust, Its most happy about 8-10 deg btdc.
Ran it, no puke, but still a little noisy on the valvetrain than before.
Could the engine getting hot have maybe affected something in the heads?
I checked rockers, torque to 23 ft lbs.
 
Lifter issues? Would explain loose rocker and noise. Excess heat is not really going to do anything to rockers, valves, etc. and you'd know if you cracked a head or destroyed a gasket as you'd likely see the mess oil and coolant make! Why no thermostat, by the way. Engines have them for a reason.
 
Well, I did go with the firing order that's cast onto the intake.
I never had a T stat on my 70 ranger and my 72 3/4 ton.
I never had one on my 76 C20 either (it doesn't get too cold here in south Texas).
The t stat will go in eventually.
I'm not too happy with the noisy valvetrain, sounds like my sons Isuzu with 250k.
I was thinking of getting an old pair of valve covers and cut them down to see if I can adjust the rockers while it's running, just seems kinda strange that they would get noisy all of a sudden.
Man!...I hate having to start removing engine components to see what's up, I guess any thoughts of adding A/C will have to wait.
I reckon ize be havin to dobba check them there wires on how I done run them too.

 
Boom said:
Where was the coolant coming out of?
Click to expand...
It was coming from the overflow tube.
It made quite a mess, the clear plastic hose came loose at the bottom of the radiator and it started flailing around squirting coolant at everyone and everything.
I had to hose and wipe everything down.
It was cool to watch, almost like a scene from John Carpenter's The Thing movie.
 
Horseplay said:
What's your oil pressure look like? Need a real gauge reading to mean anything.
Click to expand...
It has the stock gauge so there's no telling, it hangs out at about the 1/4 to 1/3 area of the gauge.
I did disconnect the coil, removed covers, attached a remote start, and cranked it.
There was a good flow of oil running down the rockers.
 
Oil pressure is crusial.
Need to know exactly if its ok.
A t-stat makes sure the engine operates at an ideal temp.
Maybe its time to do a compression test.
My 2 eurocent
 
When you said you torqued the rocker to 25 then I assume you have non-adjustable rocker arms. If they are indeed non-adjustable then you can't do anymore than confirm they aren't loose. If they are tight and they still tick, I'm afraid it is more serious. If they didn't make noise before and they are tight, then your clearances have increased or you don't have enough oil pressure to pump them up. Adjustable rockers lash or preload is set my tightening the rocker until the push rod can no longer be spun by fingers. Then you tighten another half turn. Non-adjustable count on the valve stem installed height to be fixed. Therefore you can't take up any slop because the rocker arm nuts are already bottomed out.
Low oil pressure would explain the noise as the lifter has to "pump up"
If the engine is really hot when it makes noise it could be hot enough to effect oil viscosity but it sounds like you hear the noise when it cold also.
Timing will effect the engine temp. If your balancer rubber is bad you could have spun the outer part causing the marks to be off. If timing is late, it will increase cylinder temps.
Maybe an inexpensive piston stop would help. You can check the you timing marks are correct on the balencer


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the first thing i would do is change the oil, since dirty oil can cause the lifters to malfunction.

if that doesnt cure the problem, then perhaps a heavier weight oil.
 
It's possible the rocker arm studs have pulled out of the heads enough to make them loose. Could overheating have done this?
 
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