Why does cam instal cause a spun bearing?? Is it b/c people have a 6 speed and the new cam it they take it to higher rpms?? I think i would like to do a cam swap but not with every one saying they are getting spun bearings. I would be pissed if i had to rebuild a motor with 50,000 miles b/c i changed cams.

 

not sure man..i didnt have any problems with mine. I think a lot of blame can be placed on the installer. If you are not carefull and get tons of junk everywhere, you will have problems. Silicone dirt, old gasket material etc is not healthy for your engine

 

99% you can blame on the installer. Usually the cam is dragged and pushed across the bearings, which gouges and nicks them. Then they are not long for the world.
Millions of cams have been swapped over the years in SBC without any problems, but you will always hear about the few that had problems.

I think the newer style roller cams with the larger, more square lobes are part of the deal. You just have to be a little more careful than the old flat tappet days.

 

You know, I'm beginning to think it might also be a luck of the draw type thing with LT1's. There aren't too many on this board more knowledgeable than Shoebox on just about anything related to this engine and it happened to him. I seriously doubt he's a corner cutter or does anything half-assed.

But I'm sure a good number of them are caused by slip-shod workmanship too though.

 

I am by no means a corner cutter and when I installed my cam i was more than clean. I had rags everywhere and a shop vac handy. I spun a rod bearing(not a cam bearing) 10 days after my cam install. I also had a busted headgasket, which was the reason why I had it apart in the first place. My engine builder told me the reason I spun a bearing was a mixture of the higher RPMs with the weakened bearings because of the blown headgasket. Either way, I don't think there is an explanation on why it happens, but it does, and apparently it happens to a lot of people. BTW, my engine had 84K miles.

 

Motor mileage, also.

 

I just posted this formula on another post:

Worn bearings+new cam+higher revs+not enough oil pressure=spun bearing

Oil pressure is not the greatest in all LT1s. Add that to worn bearings and then the higher revs you take it to after installing a performance cam and you have a recipe for problems.

Mine ran fine until I bounced it off the rev limiter one day. That had never happened to me before the cam install. Obviously, the new cam could easily make more power up top and could get there much quicker. I feel like if that had not happened, I would still be motoring along without the rebuild (though for how much longer is not known).

Not all engines are going to have the same amount of bearing wear, but a high mileage engine is going to be risky.

 

My car is a auto with 50,000 miles. I dont have money or time with out a running car to rebuild the motor. So with that said how risky is a cam swap? thanks THIS SITE RULES

 

The amount of risk involved depends on the amount of time and precautions you take before and after installing the cam. If your oil pressure is low to begin with then you will probably kill your motor... keep that in mind. Too many people spin the thing to the moon after they install a new cam because it pulls so much harder up high so again oil starvation becomes an issue and bearings suffer. Oil is the key here! A little dirt wont hurt anything... theres dirt in there to begin with. Friction from lack of oil I am sure kills 99% of motors rather than the grit factor from added dirt like a lot of guys seem to think. So pretty much as long as you have good oil pressure at idle and at WOT and you dont slide the new cam in with a hammer.. you should be fine

 

So pretty much a cam swap/lube system upgrades might now go hand in hand

Kinda like...headers and plugs

 

So your saying that if i do a cam swap it is a good idea to get a high flow oil pump?

 

Plenty of oil pressure is what you need. High volume is not so necessary and a lot of people will say not needed.

 

More oil pressure will definitely help keep the engine alive until rebuild time.

-Mindgame

 

My engine is creeping up on 100k, it's my daily driver and I'm not going to risk spinning a bearing after a cam install. I'm building a 355, then will swap it into the car. I figure that's the safest bet for me.

 

Well, many have heard this before, but I spun a bearing with less than 7 grand (easy miles) on my 97. It was about 2000 past the new baby cam install and about 200 past head P & P and install.

Don't know what happened. I do know that it cost me around 5 grand with my new short block.

Problem is, that unless you do a thorough analysis (or your mechanic does one) you may never know what happened.

You can bet though that your mechanic is not going to take the blame.

In re: cam installs, I had my old cam re installed in the short block after it was checked and polished. Since the cam could be installed with the engine out of the bay, it should minimize damage caused by shoving it around with the block in the bay.

Hopefully it won't happen again, but I can sure tell you that it makes you gun shy.