The Stovebolt Site Forums The Shop Area Engine Shop Looking for good head

I just pulled the head off my '54 3600, and found a good 2" crack on the #6 and a 1" crack on #4. Both cylinders had low compression, one in the 90's and the other 60. The engine had run ok, just smelled a little gassy in the exhaust and I think maybe the occasional steam. The local machine shop guy that magnafluxed it said he'd seen alot of these heads and this was a common problem. My head Number is 3835913 and the date d264 - which he told me is april 4, 1954.
My questions are; Are some casting numbers better than others for crack resistance (I've seen 848's recommended in past posts as a good head) or are they all just a crap shoot? Also any tips when looking at them, short of making the machine shop guy rich magnafluxing all the 235 heads in the country to find a good one?
Finally, I'm going to go ahead and do a re-ring on the block. What are the the telltale signs to look for to determine if any anti-freeze got to the bearings? (ie: what would they look like?)
Any help would be appreciated, as I am hoping to back on the road in the spring with out going broke. :rolleyes:

All of the Chevy six heads have a problem with cracking, and there aren't to many left without cracks. Most cracks can be welded by a competent machine shop. The 848 head is the preferred head due to compression.

I've never seen bearing ruined by anti-freeze, so I don't know. However, if you are going to ring the engine, you should get the crank ground and new bearings, so it really doesn't matter, other than for curiousity. I'll let someone with more knowledge answer here.

Mainer54, sorry to hear about the head problems. Sounds like replacement is in order for the head. Here is what sounds like a good 848 head, just ask if it has hard seats or not. 848 head
If that doesn't work out drop me a line and i will see what I can do to assist you.

As far as the bearings go- Just figure you are going to rebuild the entire engine, most rebuild parts can be gotten off from Ebay fairly reasonable. There are many reasons that you don't "just" rebuild the top end and not the bottom, the biggest is increased pressure on the bearings.

Be certain, when you rebuild, you ask your machinist to "nurlize" the pistons.(whether new or old pistons)

If you are speaking in the vein of your "Topic starter" then you will probably need to talk to Clinton about that one.-LOL

Well, the subject title sounds like.......
Signs of gylcol coolant in the oil is a brown gooey mess in the oil pan and on the head and valve cover. It looks a little different than the black gooey mess from old age and or infrequent oil changes.A little coolant won't cause immediate damage , but over time it changes the oil into brown sludge. If you have any doubts about the lower end, pull the pan.

Just thought the topic title would get some attention. I didn't realize you could sucessfully weld cast iron, but I will look around. In the meantime the lip on the cylinders seems to be .008, maybe .01, best I can tell with a feeler guage - maybe too crude a measurement, but I may need to bore the block. I need to add up all the potential / likely costs and take another look at the neighbors' 235 from a '62 truck he bought. I can get that engine for $250, of course it could just be more of the same. Any advice ? Today I took the hood off and will pull the block out of my truck within a week, so I can handle either scenario, but would like to save on the $$. :rolleyes:

That ridge on your cylinders is not wear but more probably carbon deposits. Don't pull your pistons until you ream this ridge off. Then you can take your guages and mic the cylinders correctly.

If you buy the neighbor's 235 all you are getting is another engine to rebuild. This is going to cost you some dollars but don't try to do it cheaply, but it can be done within reason. Rule of thumb is- If you pull an old engine and want to put another in- make sure you only need to do it once. Thereby it must be a new or rebuilt engine. I have a few running 235s sitting in my shop but they are old, so I won't put them in a rig until they get rebuilt.

Another rule is not to pull the crankcase pan unless you are ready to rebuild the engine. My brother-in-law told me that after I bought a running 235 and pulled the pan to inspect before I put it in. Cost of the rebuild including machine shop work was about $1,000. New cam, lifters, pistons, valve springs and bearings. I did all the assembly.

Thanks for the advice guys, I'm just trying to figure out how to explain a rebuild to my wife who already has reminded me that I told her "the truck would need only a couple of hundred bucks" after I bought it.
One other thing, Has anybody had success with welding repairs to a cracked head?

If you are looking for a cheap and temporary fix to a cracked head then welding it is the right idea, but I will say that you will end up with distortion and the surrounding metal will become weaker and prone to cracking or just plain falling apart. It is just to inexpensive to get another head in good condition. Just tell the wife that you forgot a little "0". I would hate to see you put $$$ into this and very shortly be back at square one or worse. All depending on where the cracks are, that head may not be able to be welded. If you are going to be putting new rings in, that head will be put under heavier pressure then it was before.

Pull that Boat Anchor, put in the biggest V-8 you can get, go fast!

Just trying to make another "Hacker" here! :p

If you want to see photos of bearing failures due to antifreeze contamination, go to the Dana/Clevite website. They have some good information on there. Usually it causes dropouts in the babbitt material and that is exactly what it did in my 216. The head gasket had failed and it had been driven around like that. The mains and cam bearings survived without damage.

Curious why would anyone "knurlize" new pistons? Most shops want to measure new pistons and hone the cylinder to size. Knurling in my opinion is a half *** way to size a worn piston/cylinder.

that is why so few do the knurlin on the pistons!

I have been told that knurling doesn't last very long.

I don't think it does either. Kinda like knurling the valve guides. 15K miles later, she's smoking again.

chip

Where is Mavis Beacon when I need her???

Nurl, as I recall is a verb. Meaning to cut with fluting or ridges. Therefore "nurlizing" is the realizing of that process.

Knurl, is a noun, a single ridge or groove.

What are the advantages of "Nurlizing"?

1. Increases piston diameter to exact predetermined size, quickly, accuratly and permanently.

2. The interrupted surface insures adequate lubrication.
2.(a) The valleys act as oil pockets.
2.(b) Oil carried or trapped in these pockets acts as a cooling medium.
2.(c) The valleys act as traps for detached particles of metal or foreign substances which would ordinarily break through the oil film.

3. Permits closer fit without danger of scuffing or scoring.
3.(a) The interrupted surface provides a series of expansion jounts permitting surface metal to expand sideways under heat, rather than bulge and break through the protective oil film.

4. Eliminates piston slap, stabilizes pistons, and greatly increases ring life and efficency.

Nurlizing, is only done on a piston on the two thrust faces of the piston skirt.

These same principles can also apply to valve guides.

Mainer54, Out of curiosity, did you get the head welded or purchase another? OR, did you contact Clinton for ad-vice on "good head"??

Oly,

Oly,
I'm still looking for "good head", I decided against the welding route. By the way I'm now pulling the block out of the truck. I removed the radiator, but do you need to also take out the radiator frame and the section where the hood latch is ? Also, where is the best attachment points to the block, front, back, middle ? I attached to the middle and the block with tranny still attached seems to hang up on the firewall in the back...any tips here ? :rolleyes:

Thanks

Well fellows let me add my 2 cents worth. I had a crack in my 261 and found a guy (?) to weld it up. In the end he had to surface off about 0.60 %Ran it for about 1 week Guess what water in the oil, and a garden hose out the exhaust pipe. Gave it back to this guy(?) Was told the crack was deeper than he though,repaired one more time But had to shave another 0.20 off head.Now I have to run 2 head gasket to keep the valves and piston away from each other. Bottom line about
$400.00 in head repair.plus the time to do it twice. I found the Kragen auto has rebuilt 235 heads for about $250-$300.00 plus core, I had also heard that you can get brand heads in Brazil.

Who know what you will get with head from Brazil? I would at least use protection.

YO!

Anti-freeze in engine oil is VERY destructive to bearings. Even a small amount run for a relatively short time will pit the bearings. This material loosened from the bearings acts as an abrasive, which takes out other bearings.

My former employer was running a tub grinder with a 619 John Deere engine. It had a liner with a caviation hole, which allowed coolant into the crankcase. This at first just made more blowby but it got progressively worse. One day it was fogging so bad I could hardly see the engine. I was walking over to the engine to shut it down when it LOCKED UP. This is a 300 horsepower engine turning a 500 pound hammer mill running at 2300 rpm and it stopped dead cold. My boss came over and tried to turn it over with the starter and all the starter did was click.

They tore the engine down at John Deere and 3 main bearings spun in the block, along with 2 or three rods. An engine that could have been saved by a $7000 overhaul had to be replaced with a brand new engine costing $18,000.

If you have antifreeze in the oil, DO NOT RUN THE ENGINE.

Oly,, nurlizing is not a word

http://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=knurling+&spell=1

I used Cindy's dictionary and found this-
Nurl