If my cylinder walls are good is it worth it to machine the block anyway? Or would I be OK with replacing rings and bearings in a rebuild? I wanna build a strong 350 I was thinking about ordering a new set of rings and bearings and calling it a day.

Is the stock rotating assembly strong enough to take a 500hp application or is a new rotating assembly the way I am gonna have to go. Just trying to figure out how much cash I am gonna dump into this project.

 

The cylinder walls may look fine but if there is any taper to them or if there is a ridge worn in at the top you should have them machined. If you plan on a 500hp setup, be prepared to spend some money to have the bottom end balanced. I wouldn't recommend using a crank that has been turned.

 

If the bores look smooth and are straight, you can use a bottle brush hone to re hone the surface and install moly faced rings.

Marck

 

I beleive Chevy says if it is more than .010 taper it needs rebored. It has been a long time since I rebuilt an engine so double check on .010 my memory isn't what it used to be. As far as the 500 Hp. I have built some healthy engines without spending mega bucks on them. Of course it helps if you are rebuilding a high performance engine from the factory that has a lot of the goodies in it already. Long as your not pounding on it everyday it should be ok. Before investing too much check out EBay you can pick up a high Hp engine pretty cheap. :cheers:

 

Besides cylinder wall condition what about proper clearance on the pistons? If you are going forged then maybe the block can be torque plate honed and brought within specs but if you are going Hyper eutectic then they probably will be too loose. If you just reusing your old pistons then they will probably be also out of specs. Too much piston to cylinder wall clearance. If you really expect 500 horse then you can't scrimp and go for a rebore to true everything up. If you just want a rebuild and not really 500 horse then just rering , bearings , oil pump and valve job and accept less power.

 

what is a bottle brush hone?

 

I've built plenty of motors with just a quick glaze breaking hone job and never had a problem with a clean piston bore. If you see any pitting or rust,spend the cash to bore it or you'll tear the rings to pieces on the rough surface.

 

If your really looking for a 500hp range I would definitely have it bored. I work in a machine shop durring the summers and if a block has more than .002 - .003 of taper we highly reccomend boring it. Most of these are for stock engines too. I have ball honed some also but it is generally used for customers who are looking for a cheap job not a good job. When doing the final hone anything with taper over .0003 isnt acceptiable. If you can feel any ridge at all your gona need to get it bored if you want to do it right. For a 500 hp 350 your gona need to alot of money, especially if you want it to be reliable.
Kevin


[Modified by 71vettman, 6:21 PM 12/15/2002]

 

I agree w/all of the above. Oddly enough! I'm pretty opinionated because I've done a lot of hot rods and I know what works on a Chevy (actually the same things hold true with any motor.)

There are a lot of things to look at besides the bore. First, to answer your Q about a bottle brush hone, it is a device that fits in the 3/8 drill but has fingers like a bottle brush. Each of them has a ball on the end that brushes the cylinder. It is the best hone for building motors.

Another thing to do is get a rotary file and eliminate any and all sharp corners on the block. In doing so, you'll also be removing any flash that hasn't already broken off. The theory is that a sharp corner is a weak spot that can break from internal pressure ... where a rounded corner will have a lot less of this tendency.

As for taper in the cylinders, .003 is the standard. If you run the hell out of it, even at that small amount the engine will burn oil. Not much of course but enough to make you wish you had bored it out.

When you start the engine make sure the oil system is primed. When building, make sure you Buy a NEW not reman oil pump. Take the cover off, and pack it with Vaseline. Make sure there are no air pockets. AS for lifters if they are hydraulic then just let them soak overnight in a quart of oil. That will fill them, and you can adjust the valves at zero lash.

Then when ready, fill the oil filter with oil before you install it. Then crank it over with NO! power to the coil until you have oil pressure. Assuming the valves are adjusted properly and the cooling system is full and capped you should run the engine at minimum 2,000 RPM for fifteen or twenty minutes to break in the cam. Vary speed from 1500 to 2500 in sharp bursts to change the oiling pattern over the cam.

Once the cam is broken in drop the oil and filter out of it. Fill a new filter with oil, prime the engine like you did before (no coil power), and run it again.

Good Luck! :rolleyes:

 

The same as a bubble gum hone, flexhone, dingleberry and whatever else it's called. It's a brush with carbide ***** on the end.



Marck

 

Here's what my cylinders looked like after torque plate honing. This is rebuild number two for this block.

 

i thought a line hone was better?

yes bore it. you may not see an imperfection that boring will take out. its just safer. its only going to get you 1-5hp at the most, so power isnt going to go up much just by doing this. you will need some $$$ for a 500hp small block, but dont let that stop you. if you are going for a street car, focus on torque, not hp. ive heard of crossfire C4s with RV cams obliterating their tires and doing some very impressive 0-60 times. :yesnod:

 

I think I am gonna shoot for 400ish then I am gonna buy a rough C3 and make a monster out of it