When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I think I know the answer to this one, but am hoping someone has dealt with this before.
I crawled under the truck this morning to change the oil. Found a fuel leak (fixed!) and noticed what looks like rust stains on the driver's side of the block.
I was about to get on the road to travel some 200 miles to pick up a band saw I bought, but this gave me pause. The motor was down about a gallon of coolant and the last thing I need is a catastrophic failure on the highway.
A couple of questions:
Leaky head gasket, or cracked head (or both?) (or impossible to tell without a tear down?)
Assuming that the gasket is bad (or worse), is this safe to drive for a few more miles, or does it warrant immediate attention?
Thanks, as always, for any suggestions.
This is in, btw, a 62 F-100. It's got the correct date codes, but is not original to the truck.
If there is no oil in the coolant or coolant
in the oil. Than I would re tighten the head
while the engine is hot. Also check the plugs
but if there is no white smoke in the exhaust
than I think you will be okay. Prolly have to
pull the rocker assembly to tighten the head.
Also check your pressure cap. Make sure it is
the right one and is working.
Thanks. I'll give it a try. I drained the oil and it looks clean. Can't say for sure about the coolant--it was down about a gallon (probably 500 miles or so since I topped it up). Once I run it a bit, I'll know for sure if there's contamination.
No white smoke out the tailpipes that I've noticed, but a weep at speed probably wouldn't produced clouds, would it?
What do the plugs look like? Any look
steam cleaned?
I probably won't get a chance to pull them for a week or two--I'll post a photo when I do. I also discovered a pesky fuel leak when I was under the truck--trying to get that under control first. Stay tuned.
What do the plugs look like? Any look
steam cleaned?
Took a while to get to this. Rather than try to torque the heads, I bought a gasket set and pulled the head. The plugs looked normal and all-in-all everything was pretty clean. On of the head bolts wasn't very tight and another had jacked-up threads (which I cleaned up with a die), so that may have been the cause of the leak.
Unfortunately, when I fired it up, it ran very rough. Not sure if I got some wires swapped, a pushrod is not sitting properly on a lifter (is that possible?) or what.
I thought long and hard about sealant on the intake manifold gasket. The ones that came off didn't appear to have any on them. In the end, I decided to put them in dry--should they have some sealant on them? If so, what kind is best? The roughness doesn't even out with speed, but it still could be a vacuum leak.
Nothing like fixing one problem only to create another. I dug into the valve train and found that the pushrod on the #8 intake cylinder was jammed, holding the valve open. Fixed that and fired it up--no apparent damage to the valve, thank goodness. The motor is running nice and smooth again.
In the process I had to back the adjusters off, of course. I adjusted them per the manual with a feeler gauge and it's much noisier than before. I remember seeing someone post about an alternate adjustment method--something about counting the turns of the adjuster. Can anyone point me in the direction of that technique?
It is possible that a pushrod simply wasn't installed on the lifter. You can't really get it half way on, though.
The intake gasket should not need sealer. You do need to make sure that the gasket surface of the intake and head are good - a gouge in the surface may prevent a good seal and needs to be addressed.
Start with the simple stuff, triple check your plug wires, check valve adjustment, make sure you tightened all of the bolts, etc.
Re valve adjustment, the way to do it with 50+ year old worn rockers is to turn the screw until you have 0 lash and then back off 1/4 turn. That will get you close enough. And remember, they are solid lifters. A little noise is nothing to worry about.
It is possible that a pushrod simply wasn't installed on the lifter. You can't really get it half way on, though.
The intake gasket should not need sealer. You do need to make sure that the gasket surface of the intake and head are good - a gouge in the surface may prevent a good seal and needs to be addressed.
Start with the simple stuff, triple check your plug wires, check valve adjustment, make sure you tightened all of the bolts, etc.
Re valve adjustment, the way to do it with 50+ year old worn rockers is to turn the screw until you have 0 lash and then back off 1/4 turn. That will get you close enough. And remember, they are solid lifters. A little noise is nothing to worry about.
Thanks, Charlie. I found that the #8 intake pushrod was not on the lifter as you suggested. I was thankful to find that the depressed valve did not hit the piston. So far, but the new head gasket and intake manifold gaskets are holding. I'll be taking a longer drive today, so fingers crossed.
I found the 1/4 turn trick online and discovered that most of the rockers were set pretty close using the feeler gauge. Still seems like a lot of free play to me, some of it caused by sloppy tolerances between the rockers and the shaft, so for better or worse, I tightened them to about 1/5 turn to go from "clatter" to "sewing machine." The truck seems to be running well. Should I dig in there again and loosen them up a bit or is there some room for "creativity" in the adjustment?
There is some room for error. In fact, trying different valve lash can help to really fine tune the engine. I would not go tighter than .015" with a stock cam, which is about where you are with 1/5 turn.
The easiest way is first mark the damper in 3 other locations every 90 degrees from 0 (zero) or TDC, doesn't have to be perfect.
After finding TDC for the #1 cylinder, both exhaust and intake valve will be on the heel of the cam lobe and loose, ready for adjustment.
To zero lash I tighten till the push rod is tight, tho will still spin with finger pressure. Then loosen jam nut exactly 1/4 turn. Do both the intake and exhaust valve on that cylinder.
Rotate engine 1/4 turn and then do the same for the #5 cylinder. Continue on with each cylinder in firing order - 15486372 - there are other methods of lash adjustment but this seems to be both very easy and very accurate, and also very consistent across all cylinders.
Generally a little bit "loose" means better low end torque. Too "tight" is noticeably less power and may burn a valve. When valve lash is set correctly they don't clatter, just a bit of sewing machine maybe.
If the engine hasn't been gone through in a while, also re-set engine timing, and then finally idle mixture and idle. It should purr like a kitten.
Generally a little bit "loose" means better low end torque. Too "tight" is noticeably less power and may burn a valve. When valve lash is set correctly they don't clatter, just a bit of sewing machine maybe.
Thanks--I've got it running nicely, but a little worried that I've got them a bit too tight. Next opportunity, I'll loosen them up a tad.
That's why the (exactly) 1/4 turn method works so well, it takes a lot of the guess and by golly out of it, and also compensates for any differences in each valvetrain. It's consistent across all cylinders.
A flat feeler gauge is typically going to "bridge" across any grooves or wear patterns on the face of the valve stem and usually produces inconsistent results, or at least excessive valve lash. For me, it's just a PITA. I experimented a little bit setting lash both hot and cold and found that a cold setting worked fine.
07-19-2015, 12:37 PM
