Cam bore damage

[tooldude]

Here's something you never want to see. I got a head from a member a while back with this damage that obviously could not be seen until taken apart. When I was finally able to start disassembly, I discovered it. At first I thought metal had clogged the filter and gotten into the oil passages, but it may have been loss of lubrication. The pictures don't quite show all the detail. I know it would likely be too expensive, but I'm curious whether a head with this type of damage could actually be repaired?

[ryanprins13]

Ouch! I dont know if that can be repaired but before you consider repairing it i think you need to figure out exactly why that happened. If you cant or the owner isn't willing to pay for a new oil pump or whatever else he needs to fix the actual problem then its not worth considering as it will just happen again. If its loss of pressure or metal contaminates his rings and bearings could be bad too.


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[jbibb1]

There's no doubt it can be repaired. If you had the same issue on a piece that could not be replaced it could be welded up to replace the lost material then bored back to the original specs then most likely annealed to relieve inner stresses. In most cases it's cost prohibitive to have that kind of work done to a piece that could be fairly easily replaced but it can be done

[tooldude]

This is a head I had planned on using on my Festiva which unfortunately had the unknown damage. I was curious whether it was even feasible to attempt a repair of that nature if it was a piece from a rare and valuable car, for example. I asked at a couple of local rebuilders whether sleeves could be put in and both said no. I didn't think of asking whether that opinion may be based on cost, feasibility of even being done, or just the shop's abilities. Previously, I had the head from my car in a shop to be milled and seats ground. I put new valve guides and valves in the head myself. Apparently, the head was not inspected at all, as when clean, there was obvious wear in the bore near the cam pulley - enough that I don't really want to use the head. This is the type of thing that caused me work on my own vehicles in the first place, but I let my guard down there.

[Dragonhealer]

That head was not getting enough oil. Simple enough to get a good one if you have money. In a pinch, polish the cam journals with 240 grit wet/dry sand paper followed by 400 grit, but don't try to remove all the marks, only about 1/3rd of them. use 400 grit Scotch Brite or sand paper on the cam bores till mostly smooth. Clean everything meticulously! Assemble with good quality assembly lube.If your oil pressure is good, this will last awhile, 40K +

[ryanprins13]

This damaged head that you posted the pictures of is it the one you put the money into already or was that your previous one?
When you look at it can you see why a sleeve would not work? Would it mess with the seals, oil passages or other components or weaken it too much? If not buy a sleeve, bring it to a shop and say 'i want you to put this sleeve in'.
If it cant be done and you have a lot of money in this head i have a halfass fix in mind if your interested in hearing that but i wouldn't do it myself...


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[tooldude]

This damaged head that you posted the pictures of is it the one you put the money into already or was that your previous one?
When you look at it can you see why a sleeve would not work? Would it mess with the seals, oil passages or other components or weaken it too much? If not buy a sleeve, bring it to a shop and say 'i want you to put this sleeve in'.
If it cant be done and you have a lot of money in this head i have a halfass fix in mind if your interested in hearing that but i wouldn't do it myself...


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I had the head that was on my car milled and seats ground at a shop. I bought the head pictured from someone who didn't know of the damage, just removed it from an engine. I believe he is going to take it back. I'm have no machinist experience or measuring tools, just my particular abilities and what I've studied. It seems the concensus is that cost is the problem. Logically, you have to wonder how much material can be removed from the bores before affecting strength and how to securely pin an insert so it won't spin, or the welding buildup and remachining. I wondered about doing something like Dragonhealer is saying but I can't mic the dimensions. So then it's back to the money if you don't have the instruments yourself - paying a shop to check things and be told the wear is too deep. The FSM gives the maximum wear is 0.0059 inch. Looks like when all the heads are worn out an engine swap will be the only option.

[ryanprins13]

Well you could buy some cheap calipers, measure the OD of a good cam and the ID of your bore and subtract to find your gap.
Then if its not terrible you could find some type of soft metal to solder with that can handle 250f and carefully fill in the grooves. Then take a cylinder hone for small cylinders and have at it till its smooth and round.

Or just return it


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[tooldude]

An interesting thing along these lines, I bought studs for my engine block around 1996 from ARP. A guy at ARP told me there were people racing Festivas and that's why they made studs that fit. He said there were two different heads they used and ARP made two different lengths because of that. I have the studs in my block still, used them for well more than 50K miles. Does anyone know anything about that and what heads were being used?

[tooldude]

Well you could buy some cheap calipers, measure the OD of a good cam and the ID of your bore and subtract to find your gap.
Then if its not terrible you could find some type of soft metal to solder with that can handle 250f and carefully fill in the grooves. Then take a cylinder hone for small cylinders and have at it till its smooth and round.

Or just return it


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I am not the expert here, but I don't know if there is anything that could be put on like that and hold up, or have an appropriate surface for a cam to run on. It would be interesting to try finding a material that would work but it would still need the machining. What if JB Weld would actually work? Along lines of what you're saying, the old cars had a relatively soft material applied on the connecting rods called babbitt that the crankshaft ran against.

[drddan]

IMO, welding and boring the head would be cost prohibitive. The heat would warp the head, so it would need to be milled also. So you would have the cost of these 3 things at miminum.
Heads can be had on ebay for $200, fully rebuilt.

Post a WTB, someone here may have one for you, cheaper

[jason_]

I built my bores up, milled it flat then reamed them.

You don't have to be exact, either on the mill or bore shot of the ream. Idler keeps the belt on.


Was it worth it? No. It was a long project I only put 20mins into here and there until done.

I used a lathe, lathe bed, milling machine, reamer set, and a tig. Probably stuff the average person doesn't have.

Find a new head. Shameful they don't use bearings....

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[tooldude]

Thanks for that info Jason.

[ricko1966]

The head can be cut for cam bearingsthey are very similar too little rod bearings,used to be a common repair on ohc engines that had damaged cam bores Finding a shop that still does it ,I don,t know where to point you I think Rimco and Yes used to offer this was in a jam 2 years ago swapping heads found my replacement head and can were damaged real bad.Put the head on swapped in my old cam and planned on getting my original head rebuilt 2 years later its still going strong.As long as the engine can still maintain decent oil pressure that damage isn't going to hurt anything.The cam actually floats on a pressurized cushion of oil as long as there is still decent oil pressure there is no metal to metal contact.If I had another head I'd use it if not I,d run that one and monitor oil pressure.

[tooldude]

Thanks to everyone for the responses, especially the actual experiences with this. I had thought on these things using, I guess you would say, logical mechanical reasoning, but I think this is where one really has to know what works. I was concerned with the ideas of too much oil pressure loss as well as remaining life. It comes down to the fact that this head should not be in this condition, and I was not expecting that, as it was only run around 100K mi. or less.