I was just thinking last night about this. I have a fairly high mileage engine (120k) and dont want to swap cams after hearing of people spining bearings and stuff, I just cant afford a rebuild if it breaks. So my question is what kind of gains can you get with just a good p&p job on the heads with the stock cam? and is it worth the time and money?

 

I did the heads with no cam but I also did the roller rockers.
I ended up spinning a bearing 300 miles into the breakin..

I would suggest that you just do an little overhaul and make it all happy.. you will be happier in the long run..


I had about the same miles as you as well.. Just over 100K..


The power gain was wonderful though!

 

Takes 30 minutes after you get the oil pan off to replace the rod bearings. Freshen em' up, and go to town with the cam and heads

 

You can chang the rod bearings just by dropping the oil pan while keeping the engine assembled and in the car?

 

Do the cam instead of heads.If it is in good condition and done right,it should last.If it blows up,build it better.

 

I have heard many ppl somehow warp the block when they bolt heads back on which ends up causing the motor to spin bearings. That is why you should always start fresh when bolting on a new set of heads eventhough many people have gotten away with heads/cam on stock bottom end. It is your car and your call.. if it was me however I would just wait for some extra cash and rebuild everything.

 

I had 119k on my motor when I did a cam and (had) swap a new set of heads in (they're stock) but still had the motor striped down to a short block. I did NOT replace the bearings just eh oil pump. Well to get to the point I beat on her as soon as I put it back together

Still runs strong after 2500 miles of just being beat on relentlessly. So it is my opinion that if you have a problem now it will be aggravated, but if you don’t it will be fine. Don’t be scared just do it

Just some input
Faded

 

It's my understanding that the bearings spin from being old and added stress from the higher hp. So if this is right, then changing out the bearings by dropping the oil pan while I do a head/cam swap should make everything happy and keep the enigine from being killed, and it would only take an extra hour or so of work?

 

that sounds more than worth it to me I'm going to do that also when I slap my heads and cam on.
-b

 

My thought on the heads/cam warps the block and spins a bearing it that is wrong. If the core shift was that bad new bearings would not do the trick you would need an align hone. The bearing failures that do occur are more likely worn or a result of dirt. But I am a carpenter, not an engine builder so what do I know.

 

Sure can. They take about 5 or 6 minutes a piece

 

Well I think I now have a project planned for next winter! Does replacing the bearings take any special tools?

 

Just a small flat-blade screwdriver or pick to pop the old ones out. New ones press into place. You do one crank journal at a time (two rods) then turn the motor over, do the next, turn over, do the next, etc until you've replaced all eight bearings (four journals)