Intake camshaft

[Packrat456]

What kind of damage could happen if I reinstall a cam with a spun bearing? How long could it last? I know that I should replace it and the head but I am low on funds right now and I need this running. 143461434714348

[RuckkehrMiata]

Yeeeeesh. I mean it couldn't go well...

[RustRat]

You may not have the funds now for a camshaft, and a cylinder head, but will you have the funds later for a replacement engine if this doesn't turn out good? It's a non-interference engine, but still, I don't think this will work out well.

[Packrat456]

What is a non-interference engine? And yeah, that is what I was afraid of. The engine completely going.

[RustRat]

I don't know if this is the correct term, it means that even with valves at the lowest point they can open, and pistons at the highest point they reach, will not make contact. So, even if your timing belt snaps, the engine won't get damaged.

If someone knows the correct term, please enlighten me.

[Packrat456]

Well that is good to hear then.

[kung fu jesus]

Don't do it.

[Packrat456]

So does anyone know of a way to get this fixed apart from buying another head?

[kung fu jesus]

I don't think so. Even if the area was line bored, you're still looking at machine work plus custom bearings?

The part that worries me is what would cause that, IOW did the engine's oil pump starve? I don't know. I am guessing the galley there starved for oil? If that is the case, why and what else may have been damaged. That's a lot of metal let loose into the head and other parts of the engine.

I would be concerned for the rest of the engine, but I would try to get an opinion from a more experienced, knowledgeable person about these matters.

[Packrat456]

This is what I think happened. Two Saturdays ago we had a heater hose split in two, I wasn't but a mile from my house so I drove it the rest of the way. Just as I pulled into the driveway the temperature gauge touched the red. We put two new heater hoses on Sunday evening. My wife left for work Monday morning and in less than thirty minutes she called me and said it was overheating again (she pulled over and shut it off). So when I get there to check it out I realized that the radiator split open across the bottom. Put a new radiator in Thursday morning, it wouldn't start. That's when I realized that the exhaust system was dripping antifreeze. Pulled the head off last night, and to my surprise, the head has very little warpage to it at all.

[Packrat456]

And this is what I found under the intake manifold. 1435314354
I know the one is my oil sending unit but I am clueless on the other one.

[Phatmiata]

Just get some used parts from the local junkyard, it would be way better and still than what you are about to do!

PS what is your location so I dont buy a used car from you? :teehee:

[Packrat456]

That would be great, if my local junkyards had any parts. And don't worry, I'm far enough away from you for you not to worry. And besides, it's not going to be for sale...

[Satisaii]

Knock sensor

[Packrat456]

Knock sensor
Thanks.

[kung fu jesus]

If you can't find a head locally, try Project G if you are west coast oriented, Planet Miata on the east coast.

[Packrat456]

If you can't find a head locally, try Project G if you are west coast oriented, Planet Miata on the east coast.
Ohio....

[kung fu jesus]

Planet Miata is in PA, I think.

[BoBo]

I saw the pic and wow..I would look for another used complete head. It would cost more time & money to have the cams reground if it's even possible which I don't think because just by looking at the scoring on the journal bearings of the cams, the (runout) exceeds the manufacture's specifications. That kind of damage is usually caused by insufficient lubrication from low oil level or some particle getting stuck between the bearings.

It wouldn't really matter if the scoring was very small but pictures can be deceiving. Can your really feel the scoring on the CAPS with your finger nails? You might be able to just get away by only purchasing the cam by itself and have the machinist replace or polish the camshaft CAPS. Whatever is the most convenient for you I guess, but I guarantee you will have bigger problems if you assemble the head back as-is.

[kung fu jesus]

^ that.

Whatever did that to the cam, which is a much harder metal, surely did much worse to the bearing surfaces, which are softer.

[BoBo]

I knew a guy who put one CAP backwards and damaged his CAP and the journal of the cam. However, the journal on the head was fine, that might also be the OP/s case. Anyways, the cam repair was about $180 at the time and not a lot of shops are willing to do it. The shop I knew would do some custom stuff on the head and fix the cam by grinding down the damage journal on the cam and then adding undersized bearing inserts to compensate for the loss of material and poof it's done. To do that stuff now would probably cost at least twice as much.

[kung fu jesus]

Good reference. I keep thinking a decent dressed head, used, is around 400-500.

[Packrat456]

Well isn't that just peachy

[BoBo]

I agree with KFJ, it's gonna cost you about $400-500 you're gonna have to bite the bullet. At-least you didn't have any rod/main bearing failure which is very pricey to repair.

[Packrat456]

Just found me an engine block for $50. Sweet...