The Stovebolt Site Forums The Shop Area Engine Shop Another 235 copper head gasket failed to seal

I'll cut the 5 month 235 build saga short but suffice it to say that out of everything that could go wrong on an engine build I hit about 80% of them. The most disappointing one of all was after I fired it up for the first time last Sunday night was the coolant leak along the passenger side of the block where it meets the head. It's a really slow weep and after a heat cycle and a re-torque it didn't get better.

I feel like I did everything right; decked the head, checked the block for flatness, ran a die on the head bolts, ran a tap in all the block threads, lubed the bolts, 3 stage torque sequence, used the pattern out of the manual, everything was spic-and-span clean. Still it leaked.

I read a lot on here about whether or not use any gasket or sealer material and the opinions seemed to be split and I ended up not since Fel-Pro recommended not.

It just makes me mad that on this same engine I've had the head off twice during the time I've owned the truck and both times I just reused the ratty old fiber gasket and it just sealed right up.

I guess there really isn't a question here, just a rant on the copper sandwich gasket. I was so disappointed I couldn't even bring myself to write it up here for almost a week. I even thought about using some Bar's Leaks. Then the plan started to formulate. Until I get more information I'm blaming it on the gasket. To get that information I'm going to run a little experiment. I ordered up a fiber Fel-Pro gasket from Napa and it should be here in a week. It's going on, without sealer and if it seals then FelPro is going to get some feedback on the copper gasket from my little experiment. If it doesn't seal then I'll pull it again and add some sealer around the water passages. Sounds like a lot of work but it seems to me there's been a lot of problems with the copper on the 235s. I'll keep you all posted.

Dang - that blows! I hate to have stuff like that happen. You do your best and follow all the guidelines, and it don't turn out right. And to make matters worse - likely a faulty part. Keep us posted on repair.

Personally I wouldn't use a sealer on the head gasket. there are literally tons of force developed in those bolt heads so sealer is not going to do anything. There was a post about this problem a while ago. Two thoughts were that maybe the head had been compromised with the "decking" and also maybe one or more head bolts had bottome out.

Did you use new head bolts?

It could be that your old bolts have been tightened to their elastic limit. New bolts of the right grade, when tightened to the proper torque act as springs, and will keep things tight. If the bolt has been over tightened, it can reach the elastic limit of the steel, and no longer acts as a spring, even though it may seem to be tight. When the engine gets hot, and the bolt expands, you get a leak.

So it could be your bolts, not the gasket. Just a thought.

Kurt

Sealer made for head gaskets is not a problem. Spray Copper Coat is a good product, it flat out works! The small bits of copper do what Bars Leak does for radiators, the move around and seal the weeps. I wouldn't use copper gaskets with out it.

Joe

Why not use the more modern type of head gasket from fel-pro ?


Tim

Dittos on the copper spray head gasket sealer.... Used it with great success over the years.

squire

This may smell of B.S. but I believe it to be true. I wager the copper in the gasket composition is probably at least partially if not completely recycled. What I have found in HVAC piping and building wire is some of the recycled stuff is harder and brittle and easier to kink when bending. This would not be a good thing on a head gasket. Just a thought.

One thought I have is that when you had the head decked the machine bit may have been dull enough to leave machining marks. Perhaps the cooper gasket is not sealing good against these marks.

Copper coat head gasket sealer works very well, but for a head that has been decked, it might be wise to use the newer style composite head gasket.

I agree that copper head gaskets should be great to use. I'm just not so sure yet why so many have been having problems with them lately.

I have used both the copper and the composite and not had problems with either one. But as so many posts on these forums have indicated, many are having problems with them.

I built my 261 just over 30 years ago and it has a composite (fibre) head gasket and so far no problems.

To my way of feeble thinking, if the head bolts stretched enough to bottom out in the hole before getting the head clamped down, then the gasket would do much more than just seep along one edge.

There has to be a common denominator in the copper head gasket problem. Now to figure out what the common denominator is.

Work hardened or not. The stuff I am referring to is new out of the box copper AC line sets and THHN,THWN,wire. The stuff you buy now is junk compared to what it was 5-10 years ago. Your lucky just to be able to roll out a AC line set and not kink or crack it. I work with it everyday and have for the past 25 years. We are talking same name brands with reputations in the industry not the stuff made in the Land of Almost Right.

Cheap copper is very real possibility for leaking gaskets, everything else made now a days has gone to a cheaper version! Why spend good money on new copper when so much recycled is out there.

Machining finish could also account for a leak. To rough of a finish can leave small grooves to deep for the gasket to get in to leaving multiple paths to leak out of. To smooth of a finish can let the head move around since there is nothing to bite into the copper with. As the head moves with heating and combustion pressures, the seal never sets in one place.

Time to pull it apart for a complete diagnosing, and follow up to the problem.

Joe

I probably missed out on a lot of the post, but I would look elsewhere than failure of a tried and proven product. Are you sure that you are not bottoming out on the head bolts? Was your head surface trued by someone who knows what they are doing? Also, is the deck on the block true? Blocks warp just like heads when they get too hot. I like Best gaskets, but I have used lots of copper gaskets without problems.

Are you soaking your gasket before installing it? I always thru them in the drain pan for a while. It allows the material to compress easier. As for sealer,aluminum paint works good.

Thanks for all the great suggestions guys. The plan is to pull the head and reinspect all the parts to see if there's a smoking gun. Hopefully I find something apparent. If not the new fiber gasket goes in and we see what happens. I'll keep you all posted....

Update:

The gasket arrived today and I had some time so I pulled the head for inspection. I didn't find any debris on the surface that looked like it could have caused a leak. The head side of the gasket looked fresh with a few areas that looked like it had started to oxidize. The block side had more tarnishing but nothing around the water jackets so I really couldn't see any "leak path" marks on the gasket. Upon closer inspection I noticed that the crush ring meant for the water passage around the spark plug hole was only partially crushed, see photo

https://picasaweb.google.com/lh/photo/gwtj-iOlxbSIE9XfU-e8I77Dsnwl3qS3kis-JY3pdR4?feat=directlink

Also on the head you can see the witness mark and the actual shape of the feature that hole was meant to seal.

https://picasaweb.google.com/lh/photo/LPhhRRLhhrEay0Ptk93Gpr7Dsnwl3qS3kis-JY3pdR4?feat=directlink

Is it possible that because the ring wasn't crushed it caused improper sealing? In one spot the head had cut through the copper on one hole edge. I don't know, it's not a smoking gun but its the only visual indicator something was wrong with the gasket or head. I checked the head and block with a straight edge and feeler gauge, the thinnest I have is .0015" and I couldn't get it to go under the straight edge on the head or block so I think its all pretty flat. I also checked the bolts and there is plenty of thread left on the few I checked when installed through the head. I am going to check every one tomorrow to make sure.

Last weird item I found was some weird gunk in the cooling passages as see in this photo.

https://picasaweb.google.com/lh/photo/AUYrzKgIDYxCM-D59DTzH77Dsnwl3qS3kis-JY3pdR4?feat=directlink

I have only run the engine for about 30 minutes for initial warm up and everything was clean; hot tanked head an block, new water pump, new radiator hoses, new radiator (bought in 2000 but stored since), new antifreeze, and distilled water.

Tomorrow I hope to clean everything up and reinstall with the new fiber head gasket. If anyone has any thoughts on the photos, especially the coolant gunk, let me know.

From the pic it looks like your head is drilled for a 261 with the steam vent holes.
I wonder is those holes are sealed well enough with a 235 gasket.

Denny, the hole you have marked is the oil transfer hole for the rockers.
I just looked at a used copper gasket and it has the signs of the same missed contact on the same hole, plus the five other matching holes.

I agree with Dave, that looks like the oil transfer hole Denny. That feature is on all three of the head gaskets I have. Here's a picture of the old gasket, the installed but failed copper gasket, and the new fiber gasket all stacked on each other.

https://picasaweb.google.com/lh/photo/n-WLhIU5nBMXwcIY6kn7O77Dsnwl3qS3kis-JY3pdR4?feat=directlink

Due south of each cylinder opening you can see all three gaskets have the round hole. On the old fiber gasket you can clearly see the witness mark from the larger head feature.

Like I said before, I'm not sure its the cause of the leak but it is suspect. I have the approval of my social planner to work on the truck today so I'll see how far I get and keep you all updated.

Yes, its an 848 head. The casting date is '59, same as the block.

Dave,

If the head has been drilled for the extra 261 coolant passages, would it be worth a try using a 261 head gasket?

Rockauto.com has one for about $22 (FEL-PRO Part # 7782B) and a head-set of gaskets for about $30 (FEL-PRO Part # HS7782B)?

Tim, It is hard to say.
Only the copper gaskets seem to have the sealing ring around the area shown in Ringleaders link. I have a NOS 261 gasket and it does have the sealing rings around the steam holes but not on the holes shown in Ringleaders copper gasket.
This is a good topic.
I have seen the blue Perma-torque gaskets leak on the pass side before so I will be glad to here if it works.

I got it mostly together today but when I went to put on the new hei from langdons the rotor was missing and I had already pulled the stock stuff. Parts stores were closed and it was getting dark so it'll have to wait till next weekend. I have a few more theories and will report in full when I fire it up.

I just got my head for my 49' with a 55' 235 back from rebuild. As I was preparing to re-install it using a copper gasket my dad pops the question did you put a thin coating of grease on the block and head surfaces? I looked at him puzzled.....why? It helps to seal the gasket and allows it to float into place as it is compressed. The way he has always done it. My dad is 83, retired farmer and life long auto mechanic, GM certified. He worked on these old trucks when they were brand new. I don't argue with him.....I have no leaks what so ever.

Cliff notes version: I got the engine running tonight. I got it warm enough to open the pressure cap and dump into the catch can so it probably saw 7 psi or so. No leaks. I should be excited but I wussed out on my experiment at the last minute. Here’s the full story, sorry if its long winded...

When I pulled the head over the weekend and inspected it I reported back the oddity with the copper gasket water jacket sealing ring and it seemed like the likely cause. When I went back to clean everything up I started to scrutinize the block deck closer. In some areas around the water passages on the driver side there was discoloration on the block that looked like old rust. I stoned the block before assembly and thought nothing of it since it was flat. Now I looked at it as another source of the leak. You can’t feel it and can’t catch a nail on it but its clearly slight pitting on the deck. Here’s a photo;

https://picasaweb.google.com/lh/photo/9wLeNJpQ06K-67PkFyHU6b7Dsnwl3qS3kis-JY3pdR4?feat=directlink

The photo makes it look way worse than it is (it also makes the machine marks look really rough as well but they also were pretty smooth). I’m an engineer by training and I’ve designed some metal-to-metal seals in the past and I know they can be finicky (sp?). Then I started to formulate the theory that if you have a flat well decked head AND block you will probably have a high success rate installing the copper gasket dry. I also figured in my head, if you have anything else you probably be opening up your chance of failure. A dry fiber gasket OR a copper gasket with some sort of sealant should seal up in those cases. So I was working on getting ready to install my head gasket DRY in the interest of science and to the benefit of stovebolters everywhere. I was mentally preparing myself for the possibility of failure and I was ready to accept that and tear down again if it happened. I was marching down that road and then something just came over me. I wussed out and put some sealer around the suspect water jacket holes on the block side of the gasket!

So I feel a bit bad but the way this project has bee going I needed something to go right. I am happy to report with the minor amount of sealant I applied it didn’t leak on the first test run. I do think there’s some interesting questions on the issue still like; is the water jacket hole an issue on the steam vented head?

As an engineer I also would love to know the data on new installed head gasket failures including which surfaces were decked, was sealant used, did the head have the steam holes, and which gasket type was used. Knowing some of that info would help sort out the theories.

I also got to wondering about the copper gasket tests designers did when coming up with the gasket design. I imagine they had a head and block decked to their flatness specification AND most likely to their SURFACE FINISH specification. People worry about flatness all the time but I rarely if ever hear anyone talk about surface finish. It’s important on metal-to-metal seals and if it’s not right it increases the chance of failure. I would bet that if I measured the surface finish on the deck of my block at the area of the photo it wouldn’t be as good as the rest of the deck even though I couldn’t tell the difference with my finger.

I’m not sure any of this info help anyone but it help to write it out, thanks for reading.

Thanks for the report. Congratulations.

Forgive my rant, below, on "steam vented head"

The term "steam vents", presumably referring to the six additional coolant passages between the siamesed cylinders in 261 blocks/heads, is a misnomer introduced by Jim Carter (most likely) and promulgated because it sounds neat?

If there is steam in the block or head, something is probably wrong with the engine's cooling system. All parts/aspects of a cooling system are designed to prevent boiling (over-hating): all parts of the design - not just the extra passages needed to properly cool a 261.

Ringleader, I too believe finish is as important or more so then flatness of a deck. With out the grip of machine marks, the gasket has nothing to hold on to. You have a much better chance of sealing a slightly rough finish, then a glass smooth surface. Perfectly flat surfaces are different then smooth surfaces, but due to the nature of a engine block and head surface, getting one dead flat is pretty tough.

I would also bet that copper was a left over design from years earlier and a quality fiber gasket were still in the future, so a combination of material was used.
I had the chance to use some NOS 1970 Pontiac head gaskets on a 455 a while back. They had steel on the block side and fiber on the head side. Directions said to spray the steel side with Copper coat to "heavy consistence film". Even with that, they were seeping after a 1000 miles. I replaced them with Felpro standard blue gaskets and problem went away.

Joe

Thanks and forgiven! I just started my 235 education, I haven't even heard the term until I started this thread. Based on your photos the hole in question on my head isn't even the misnamed steam vent holes. My head has the colant holes near the center of the cylinders but the ones around the spark plugs are the ones causing concern.

I think I probably misread Dave's post early on and imposed the name on the feature in question.