Porous casting solution?

Upon further inspection of one of the heads of my 82 LP5000S some pinholes exist under the fire ring of the gasket one one cylinder. Skimming the head is not an option as the holes are too deep (such a deep skim would hit the valve seat). The holes might be due to poor castings or corrosion (the car sat in the desert for a few years full of rusty water).

 

Welding might be an option but I have been told that might be risky with such an old and mediocre casting.

 

Is anyone aware of how hot the head might get next to the fire ring and of there is any (epoxy type?) coating which can be applied in such a critical area?

 

Many thanks to all.

 

PS will post pics later in the week.

Upon further inspection of one of the heads of my 82 LP5000S some pinholes exist under the fire ring of the gasket one one cylinder. Skimming the head is not an option as the holes are too deep (such a deep skim would hit the valve seat). The holes might be due to poor castings or corrosion (the car sat in the desert for a few years full of rusty water).

 

Welding might be an option but I have been told that might be risky with such an old and mediocre casting.

 

Is anyone aware of how hot the head might get next to the fire ring and of there is any (epoxy type?) coating which can be applied in such a critical area?

 

Many thanks to all.

 

PS will post pics later in the week.

 

My thought is that welding is going to be your best option.

I too agree that welding is the way to go. Porosity or corrosion eventually ends and there is good material to weld to. A skilled welder will be able to easily assess the situation for you. Also if it is a tiny repair there are places that specialize in microscopic welding (often used to repair injection molding tools). These guys can make welds so small that you can bearly see them. Maybe they can fill a porous spot with minimal damage to the surrounding metal.

weld it.

I will post some pictures when I get the heads this evening. One issue is where I live, nobody here can do that kind of delicate work.

 

 

 

 

John, another thing that no one has considered, when you weld, you can warp the head. That is unless the welder has an oven that

you can heat the head in to start with.

Chadbourn Bolles

 

I will post some pictures when I get the heads this evening. One issue is where I live, nobody here can do that kind of delicate work.

 

The lack of a good place to do it is what is dissuading me. I may have to send the heads somewhere to get the pinholes fixed. I will know more when I see the heads this evening.

 

Chad, we installed new valve guides after all. I will return your stuff next week.

 

 

 

 

 

Epoxy vacuum impregnation can be an option for porous castings. We use it in aerospace applications. Here's a link. http://tinyurl.com/l8ajfs

The head will probably have to be skim cut after the weld in case of high/low spots, so the minimal warpage (if done correctly) should not be an issue.

Ok, for reasons too painful to get into here I think I will send the heads overseas to get the eroded and porous areas repaired (welded) and to fix at least one valve seat which was mangled (?!) when the new guides were installed. Maybe I will replace the seats with some nice beryllium copper items as a complete set of OEM ones are about $500 anyways (just do not breathe the dust when you machine them).

 

If it was your car, who would you take it to? I have a friend in Toronto who does a lot of delicate work on vintage 250 series Ferraris and I will ask him this evening, but if you wanted the Lord's own valve job for your beloved Countach where would you go? Anyone ever had similar problems and been very satisfied with the job done?

 

Living where I do, I have trust issues (but of course I trust Chad).

 

You will see horrifying pictures this evening (the laptop battery died last night before I could post).

 

 

 

 

 

 

Here we go. Have decided to pressure test the head to learn the extent of the holes in the metal. I have more pictures, but some difficulty uploading.

 

It looks to me like you have had water in that cylinder, as the adjacent chambers look to be in much better shape. I would definitely reccomend the pressure test. My best guess is that you either have a pinhole or a crack in a port or under the valve seat that leads to coolant.

Ok, for reasons too painful to get into here I think I will send the heads overseas to get the eroded and porous areas repaired (welded) and to fix at least one valve seat which was mangled (?!) when the new guides were installed. Maybe I will replace the seats with some nice beryllium copper items as a complete set of OEM ones are about $500 anyways (just do not breathe the dust when you machine them).

 

If it was your car, who would you take it to? I have a friend in Toronto who does a lot of delicate work on vintage 250 series Ferraris and I will ask him this evening, but if you wanted the Lord's own valve job for your beloved Countach where would you go? Anyone ever had similar problems and been very satisfied with the job done?

 

Living where I do, I have trust issues (but of course I trust Chad).

 

You will see horrifying pictures this evening (the laptop battery died last night before I could post).

 

I would send them to Evans Automotive as his machinist does some excelent work on Countach heads.

 

They did a 17 angle cut on my heads using a serdi valve cutting machine.

 

With George you can rest assure that all the work will be done right and timely and your parts will be returned safely.

 

If you need their address and contact information just send me a PM.

 

Sincerely Vic

A good high heat and durable epoxy can solve all of your problems without expensive milling operations.

 

I filled a deep flame trough (almost a quarter of an inch deep and 3/16ths wide) between two cylinders caused by a head gasket failure on a 476 cube (.100 overbore) chevy big block, 13 1/2 to one static compression ratio with JB weld and ran this engine for another three years. I would NOT recomenmend JB weld at this time, even though it worked fine without any flaw. There are now many more options to choose from that are much better than what we old-timers had to deal with.

 

Your immediate problems lie under the sealing surface of the fire ring of the gasket. All you need is an absolutely flat surface for the new head gaskets fire ring to seal upon. Modern epoxies can solve your gasket sealing problems with very little expense. It can all be done with little more than a hand held file and some patience!!

 

What I would be worried about is the degradation of the combustion chamber. It looks like something grenaded in there causing some deep pitting that must be taken care of. If the pitting is due to water, then you must find where it came from. If it is due to detonation, or something such as that, then you must find the problem or it will destroy your reconditioned engine in short order. Take your time and evaluate the problem before going on.

 

No one can solve any problem unless they understand why the problem actually relates to them!!

 

God Bless

 

Dennie

Thanks for the idea, can you suggest a brand name of one of those products? I want to learn more about them.

 

As for the source of the damage, the car was parked for almost a decade, half of that time it was out in the desert, about 2 miles ffrom the sea. Some valves were propped open for a looong time. All the other cylinders looked ok, 2 of them looked terrible. Those cylinders were full of sand when we opened it up. Sand, combined with moisture and salt from the sea is not nice.

 

We have put in new guides and are almost finished new seats (I am not happy with one of them and want it redone). I then want to get it pressure tested before I decide what to do about the missing metal.