Bad headgasket or intake, 345

J

jaskispyder

Member
1210 pickup (1973)
history: thermostat failed closed. Cooling system is not too bad... No real scale but I flushed it and had issues with boilover without thermostat and that was unusual with this truck. This made me buy the "exhaust gas in coolant" tester. The results are negative... No color change. So I performed a coolant system pressure test. I pumped up to 8lbs and left it all day. No loss of pressure, to speak of. So, I tried cranking over the engine and it was hydrolocked in cylinder 3. I pulled a plug and it was wet. I turned over the engine and coolant came out that cylinder. Sigh.

So. I am guessing the headgasket is bad, or a cracked head. Does this sound about right? Any chance it could be related to the intake gasket? Is there a way to check the intake? I do get a little white exhaust on the driver's side of the vehicle, and sometimes it is hard to see.

No water in oil, no oil in coolant.

Any tips of looking for intake leaks? Any tips on removing the heads? Do I have to pull the distributor and exhaust manifolds? I have a ihc service manual. I have changed headgaskets on a fuel injected car, so I am not concerned, but I am just looking for some short cuts.

Thanks!
 
Put some compressed air into the spark plug hole of the cylinder in question with the valves closed and see where it comes out. However I will say that I have had a few 345's fail leaking into cylinder 3 or 5. It was a rotted out head gasket every time.
 
Just an update, headgasket is bad. You can see the clean area. I am checking for warped heads, today (finally got a "real" straight edge, for such things). I May have to send out heads to be shaved, if bad, as no one in town does heads anymore :(
 

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You're going to want to shave those heads. Iirc the new head gaskets are .040 thick and the old steel shim ones are .016. Check the seats and guides while you've got the heads off. Next question how to the bores look?
 
Thanks, I really don't want to get into a full rebuild. The engine ran just fine until a thermostat stuck closed, then the headgasket leaked. There could be a warped head because of the overheating. I heard about the head gasket difference but some say it is fine, others disagree. I need to get this out of the garage, to make room for other projects. If it needs a rebuild, I would probably just order a rebuilt engine, as we don't have any local (4 hrs away is the closest, quality one) automotive machine shops.

Bores look ok... Only 60k on the odo, and no ridges, or marks. Thanks for the input!
 
It will work, but I think you'll loose about 1/2 a point on the compression ratio. Glad the bores are ok, water can rust them pretty quick. If it ran smooth and didn't smoke on startup the heads May be just fine.

Do you think any coolant leaked into the sump? It can wreak havoc with the white metal in the bearings.
 
Yeah, it is my "project truck"... I am ok with a little loss of compression. No water in the oil and no combustion gases in the coolant. I was stumped until I pressure tested the cooling system and found chamber 3 to be full of coolant. I let it sit overnight for the test. Cooling system is clean, no scale or rust. I really think that rs copy thermostat screwed up the head gasket. It was running fine before that, no loss of coolant, ran cool, etc.... No oil use, but it did leak. The exhaust was always clean, no residue on a white rag, etc.

I closely inspected the heads for the typical crack (jewelers loop). That is why I am thinking I should be ok putting it back together. I will also measure the block to see if it has a matching warp (if heads are warped).

(yeah, I am probably over thinking it, but I would rather error on the side of caution and learn as much before putting it back together). I pulled heads before on a different vehicle, but that was because of broken exhaust manifold bolts.
fdchappie said:
it will work, but I think you'll loose about 1/2 a point on the compression ratio. Glad the bores are ok, water can rust them pretty quick. If it ran smooth and didn't smoke on startup the heads May be just fine.

Do you think any coolant leaked into the sump? It can wreak havoc with the white metal in the bearings.
Click to expand...
 
Think you are good to just swap the head gaskets, based on the information you have provided us.
A couple of must do"s below.
1) immediately drain the oil. With the plug removed and the pan under the engine, pour 2 qts of new cheap oil into the engine so you can get the most of the water out of the pan.
Then refill the engine and change the filter (fill with clean oil before installing).
2) with the distributor removed, spin the oil pump (cw rotation) so you can pump the water out of the bearings and clean oil in. Fdc mentioned the damaging effects that coolant can have on bearings and iron parts.

3) the head and block gasket surfaces must be clean enough to eat off of before applying the new gaskets. Even oily finger prints can compromise the sealing of modern gaskets.
A. I scrape all surfaces with new razor blades to remove any left over material. Vacuum out the bores and stuff with paper to keep debris out from the next step.
B. Then I stone all surfaces with wd40 (kerosene works) with a large stone or flat block and wet/dry 320 grit sand paper until clean steel shows.
C. Using paper towels and carb or brake cleaner, wipe the surfaces squeaky clean.
D. Oil the bores making sure to get clean oil down along the pistons and bores to flush out any water.

Install the gaskets dry and clean unless you use the old style embossed steel gaskets.
 
Checked heads with real gauge. .004 fits under bar on both heads. So. Looking to get them decked. As that is above spec. Sigh. Here is pic of gauge.
 

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I feel your pain.

I'll throw in what happened to me when I once lost a head gasket on a 345 that had 100k on it, and it was the nicest running sv8 I've ever had. Had to run it for 50 miles before I could pull the heads and replace both gaskets; steam was coming out the right side tail pipe. The oem shim style gasket looked just like yours - a clean spot connecting #6 and #8 hole. Oil looked like a milk shake at this point. Without going into my circumstances at the time (living in a rat hole apartment), I had to do a cave-man repair out in an alley out in the open. One Saturday a friend helped me remove everything that it took to get the heads off. Had a case of carb cleaner and brake cleaner. The head wasn't cracked or warped (dodged a big bullet there), so I took a wire brush on a drill and cleaned all the combustion chambers, sprayed all the milkshake down the valley and into the sump, cleaned the lifters, cleaned the heads with spray cleaners, etc. Put it back together with felpros and got'r done just as it began to rain. Here was the thing, though. I drained the oil (like Robert said), and ran a can of sea foam in fresh oil, ran about 50 miles, drained, refilled, more sea foam, then repeated after 100 miles. Very cheap insurance to do that and try to get all the glycol out of the oiling system. Got curious about how much damage May have occurred to the rod bearings. Went down to the IH dealer in west sacramento one night with #5 and #6 rod bearings in hand. They examined them and said they looked okay except for possibly some slight erosion, but they weren't otherwise concerned, so I replaced all the rod bearings, laying on my back in a gravel alley. Again, $50 is cheap insurance.

That 345 ran so much smoother after this, which I attribute to the slight loss in the compression ratio due to the felpro's thickness, and removing the carbon from the chambers didn't hurt either. A few years later the guy that bought the rig off me told me he put another 100k on the engine without incident.
 
Thanks, I am probably ok, but I I May make the trip to have them shaved. I checked the block.. It could be .003 off also. Lucky for me, no water in the oil and I will flush the passages with new oil and drain it out (a few times). I was burning coolant, but not losing it into the sump.
 
Ok, after much debate and searching, I was able to find a guy that can mill the heads to make them flat (for a reasonable fee and not 4 hours away). Any recommendations on the amount to mill off and still have the intake fit? I read one article that said .020". I was thinking just .005" or maybe .006", just to make them flat. I am not concerned about a drop in compression from using a composite head gasket (.040" compressed, vs .018" steel compressed). Anyway, going to talk to the machine shop to get an opinion. Thoughts?

Thanks
 
A number I've commonly seen on the 3 sets of heads I've had done is around .012. Beyond taking out the warpage you measured at .004, there is a bit of material that needs to be removed to true up any mounting issues in the surfacing machine.
 
Drove 3.75 hours (one way) to have a shop magnaflux and mill the heads (.008). I installed them this weekend and am working through the rest of pieces to get the engine back together. Engine/timing was rotated as stated in manual and not touched for dis-assembly and installation.

Anyone have a clue why the oil passage to the rocker is not direct, but is off-set and uses the head-gasket gap? I thought it was odd, but seems to be the setup.
 
That is common practice, used to resolve where the gallery can be machined. Many times the design and construction of the engine performance optimization comes first and where the oil passes from point a to point b comes second. In some cases it is not practical to exactly line the passages up without compromising mechanical design.
 
Thanks, that makes sense.

Looking at cranking over the engine (no plugs or accessories hooked up) to check for oil flow out the rockers, just as a double check before putting on valve covers. I will squirt some oil in the cylinders before hand. I didn't pull the distributor and would rather not go through that and make a tool to prime the system.
 
Just a followup. I cleaned everything up and painted what I could. Heads were milled .008", no cracks. I have put about 50 miles on it and all seems well. I had to order a new thermostat, which came in today, as I am running one without the blockoff on the bottom as that is all I could get quickly (locally).

Coolant temp is running spot on and oddly, coolant gauge is now higher than it has run in the past. I am guessing an oddity in the gauge and I checked the ohm reading on the sensor and it is spot on with what others have seen.

One thing learned... Cork gaskets don't last 45 years... Mine were hard and crumbled when removed.

I had no buildup in either the oil or cooling system. The combustion exhaust gas test for detecting bad head gaskets did not work in my case, but a coolant pressure test did.
 
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