A cam bearing fail

[cruisintalonawd]

After taking the cams out one of my cam bearings has fail. It was so bad that it put about a 1/4in. groove in the cam. I want to know it the heas is salvageable. i doupt the cam is.

 

[assault187]

Most likely not bt post some pics of the head

 

[Freerevving]

cams don't undergo the same pressures that the rest of the engine does... the surface will probably work fine as long as it has the same diameter.... it'll just have an extra oiling groove, although I would say that 1/4" is too much. The the head is harder to repair than the cam, but it is also easy to replace the camshaft

 

[ShawnsGarage]

Pics will make it a lot easier

 

[99gst_racer]

You have bigger problems than you think, if you ruined a cam bearing - 4G63's don't have cam bearings. But, I believe you're referring to the cam caps where the journals of the cams ride on.

A buddy of mine starved a head of oil breifly, and it grooved the head and cams, but not too badly (he caught is earily). The head and cams were salvagable by lightly and carefully removing the high spots with some sort of fine grit abrasive (sandpaper, I think).

Honestly, if the damage is severe, I'd consider replacing the head. A 1G head can be had for $100 these days.

 

[cruisintalonawd]

Yeah thats what I'm talking about as soon as I can get a good camera I'll post pics. but I went to the junk yard today and they got a N/T dsm that ran when they got it couple days ago so I pulled the head, got it for $105.

 

[cruisintalonawd]

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thats about the best my crap camera can do ill barrow my girl friends tomarrow

 

[Freerevving]

the cap (top half of the bearing, btw) is replaceable, but more than likely that U shape is burned into the bottom half of the bearing which is not replacable...

having the head repaired at the bearing will be more expensive than starting with a good used head, and most machinists aren't willing to do it... with the cam it's almost the same deal, but it's much more likely that someone is willing to repair it... Also, with the welding and machining involved in repair, it doesn't guarantee that it the weld will hold, and surface hardness differences can cause problems too.

I would only recommend it if there were a lot of money invested in special head work.... other than that, use a new head and camshaft.

I highly recommend that you swap the internals over from your FI head (well, the valves and a pair of good turbo cams), but you should have a valve job to ensure that the valves to seal right... You could just use the N/T internals but they are inferior... sorry if I'm the bringer of bad news.

--Mac

 

[architechnik]

I would be rather concerned about the rest of the engine as well. In the background I can see there is quite a bit of burnt oil, not just minor dirty oil. Was there some incident that starved the head completely for an extended period or is that from long term wear? When I removed my head after 200k it didn't look like that in there.

Try DSMGraveyard or just a local junkyard and compare those. (With as much buildup as you're experiencing, it might be excessive exhaust valve blowby through the stem seals as well.)

 

[cruisintalonawd]

yeah well im just peising this motor together for a FWD laser that im selling. The motor had 180k on it and im sure its just wear. I checked all the main/rod bearing and they all still look good.