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#1418154 07/26/2021 1:12 AM
Joined: Nov 2011
Posts: 47
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'Bolter
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So, I have a 51 3100 that was a Barn Yard find that I was able to get running fairly easily. Original 216. (can see it in the projects forum) Getting some sticky valves loose, checking compression in the 85-90 range, a carb rebuild, oil change, and it was running on a hot wire and an independent gas can.

I only ran a few times for a few minutes. Worked on the cooling system. Couple of replacement freeze plugs from pin holes, removed/flushed radiator a couple of times, cleaned/lubricated water pump, new gaskets, removed T-stat., removed/soaked/cleaned rocker arm assy's. Moved on to interior and removed the ex. manifold to repair the studs.

Fired back up today, still on hotwired system. Ran for a 2-3 minutes at the most with water, no smoke, no sputtering, or anything. Shut off, check oil. Now milky.

Drained oil, removed lifter cover/v-cover, only showed just a smidge of milky oil at front lifters. No oil at all on rockers.

A few months back, I noticed they weren't getting any oil, and they were caked with plugged with muck. 1st time starting up since I put all that back together. I do know that the hard oil line can cause problems and can become brittle and crack.

So, are my only 2 culprits a blown head gasket, or the oil supply line? Is there a particular area where water can cross to oil at the head gasket?



Thats all I can think of, other than cracked block. Removing plugs(which are new), they checked ok for an old motor, and it never showed any signs of smoke out of the open exhaust manifold.

I left the oil drain plug out and poured some water in the radiator and a little water/oil came out, which again, to me, seems to point to head gasket.

Joined: Feb 2004
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H
Kettle Custodian (pot stirrer)
Kettle Custodian (pot stirrer)
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The tube that passes through the water jacket to oil the rocker arms can develop a leak. Try disconnecting the tube at both ends and putting a little air pressure to it to check for a leak. The upper end of the tube is attached to the oil coupling at the center of the rocker arm shaft. The lower end is attached to the engine block near the exhaust pipe, next to a sheet metal part called the "oil distributor". That device restricts the oil flow to the rocker arms until at least 15 pounds of oil pressure goes to the main and cam bearings. If that tube is clogged, or the oil pressure gets very low, the rockers won't get oiled.

Putting enough air pressure into the radiator to check for head gasket leaks or a cracked head can damage the radiator and/or the heater core. Try bypassing the heater with a loop of hose, and connecting the upper and lower radiator hose nipples on the engine with a pair of flex hoses coupled together. Then plumb an air hose to the engine block coolant drain and put 10-15 pounds of air pressure to the block. If the pressure leaks down, you've got a leaky gasket or a crack somewhere.
Jerry


"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
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'Bolter
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The oil pipe is a likely culprit at this age . I have recently done a repair to one , the joint behind the push rod cover was poor . It leaked water out of the block and down the cam follower gallery .

Joined: Nov 2011
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'Bolter
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Thanks guys.

I pressurized the system with 20 psi, buy bypassing the radiator (plugging off at top and bottom of water pump) and putting an inlet at the T-stat housing. It held fine. I went ahead and pulled the pan to clean the screen, check the status of the oil pump for specs.

I've read somewhere once before, and not cannot find it, that there is someone who makes a more modern type oil line kit to run thru the block. Can someone fill me in on if they are still available?

Thanks
Chris

Joined: Aug 2018
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'Bolter
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Chris, I believe this is the kit you are asking about: Rocker Arm Oil Line Kit. A little pricy since it's not hard to duplicate with normal HW store fittings and some minor modification, once you see one, but this has all the pieces in one kit.

Doug


1947 2nd-Series GMC FC152 3/4-ton
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1953 Chevy Bel Air Sport Coupe Powerglide
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Kettle Custodian (pot stirrer)
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A couple of those fittings are definitely not normal hardware store stock, and the tubing is 3/16" OD copper tube, also not a normal stock item at most HW stores. That kit is actually worth the price and then some. DO NOT substitute 3/16" OD steel brake line for the copper tubing- - - -it will rust out.
Jerry


"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
Joined: May 2015
Posts: 9,830
Housekeeping (Moderator) Making a Stovebolt Bed & Paint and Body Shop Forums
Housekeeping (Moderator) Making a Stovebolt Bed & Paint and Body Shop Forums
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I agree with Jerry - just buy the kit. I think you'd spend more money than that tracking down the special fittings. Although I may have a couple of them in my collection if needed, being the son of a plumber. wink


Kevin
1951 Chevy 3100 work truck
Follow this saga in Project Journal
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1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car)
Busting rust since the mid-60's
If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
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M
'Bolter
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I would try the old time honored dry/wet compression check. If the head gasket is bad it will show you where it is leaking. Doesn't take long.


1946 1-ton Panel
1952 1-ton Comml. W/Grain Body
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'Bolter
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Mike, fill me on on that please.

I've put water in along with the 20lbs of air pressure in the block. No water leaked out anywhere, with the pan removed. Unless, maybe it happens only when its running. Possibly?

In the mean time, I went ahead and ordered the new line kit. Kit wasn't too bad, its the dang shipping that boils the blood. Another 25% increase, lol.

Last edited by chrispy; 08/07/2021 9:38 PM.
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H
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First check the compression by simply spinning the engine over with all the spark plugs removed, and record the compression readings you get on each cylinder. Then go back and add an ounce or so of oil to the cylinder before checking the compression and see if there's a noticeable change. That checks the sealing ability of the piston rings. Neither way will reveal a leaky head gasket, unless it's blown out between cylinders. Locking the crankshaft and putting air pressure into the cylinder, called a "cylinder leakdown test" is a much better way to check for a leaky head gasket. Be sure both valves are closed, put the transmission in gear and set the parking brake and/or chock the wheels, and pressurize the cylinder by brazing an air hose fitting into a spark plug shell. Listen for leakage at the oil filler, intake manifold and exhaust pipe for air leakage that indicates valve problems or leaky piston rings, and look into the radiator for bubbles that show a cracked head or a blown head gasket.

Your pressure test of the cooling system has probably already done a better job of checking the head gasket and head than a compression test or a cylinder leak test can do.
Jerry


"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
Joined: Dec 2003
Posts: 1,060
M
'Bolter
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What HRL said. Re reading your first post, it said you had compression and the engine ran OK. Have you pulled the side panel and looked at the oil line connection? You might also remove the cover for the oil distribution parts that HRL mentioned. It may have somehow frozen up and just turned off the oil flow to the rockers. This is a long shot, but since it is part of the entire process it is worth a look. This the small cover behind the manifold on the drivers side. It is also possible to have the two gaskets misplaced.I am looking at a 48-51 shop manual and the instructions are on page 6-39.


1946 1-ton Panel
1952 1-ton Comml. W/Grain Body
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Something I've always wondered about is how easy it would be for water to pass through the vents in the valve cover, The drain tube for the cowl vent can dump water on the VC if it's not positioned correctly. Also, the seam in the hood runs directly over the VC and can leak water when it rains. Something to look at in any case.


1950 3600
1951 4400
Gazz
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'Bolter
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Ha exactly what Gazz said is a thing. I actually sealed the seam of the inside of my hood with permatex because of seeing water sitting on my valve cover after a rain. So it had to be goinig in the engine with the open vents. Something to consider.


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