Improving a 283

[Willshook]

It's your engine, but I wouldn't. Scoring isn't likely - and it's not fatal - but more likely the bearings are shot or there's low compression.

For an old engine, the best approach is to:

Drain the oil as much as possible and replace the filter, filling the filter with oil.

Replace the oil with a break-in oil, being careful not to over-fill. Pour the oil in over the rocker arms to be sure they're wet

Pull the plugs and squirt a healthy amount of oil in the bores. Wait a day.

See if it'll turn over by hand. If not...it's probably got Issues.

If it turns over easily, remove the distributor and spin up the oil pump...if you can get pressure, and you get oil to all the rocker arms, you're probably in fair shape.

Time it to 12+ BTDC, make sure you're getting gas to the carb and give it a shot.

Oil pressure and compression will tell you a lot more about the engine condition than "cleaning it out", and few oil changes will get rid of most of that gunk - especially with a little SeaFoam solvent in there.

Having done a lot of "barn finds", I can tell you that this is a case where "half measures avail us nothing" - either start and run it, or tear it down for overhaul. Anything in the middle is just going to end up breaking the engine regardless of it's condition.

Just my $.02, and worth every penny I'll shut up - good luck!

[RustyPile]

Originally Posted by MikeB

I certainly remember the 301 craze, but wasn't sure which year blocks would work. In the late 60s I actually bought a 283 block that had been bored to 4". When I took it home and pressure washed it, I discovered a crack in the lifter valley, probably from someone running little to no antifreeze. I then took it back to the junkyard and got another 283 block.

I wanted to go to 4", just to say I had a 301, but the machinist talked me out of it, so it became a 292. With Power Pack heads and stock valves, a 301 probably wouldn't have worked any better. Wish I could remember all the parts, but I do recall it having domed pistons and some kind of Isky or Erson cam. Oh, and Hedman 4-into-2 headers!

As you know, it takes a bunch of RPM for "small engines" to keep up.. The advantage that extra .060" gives you over a 292 is big 2 inch intake valves will clear the top edge of the cylinder.. The 301s I built all had the fuelie heads - 2.02 intakes and 1.70 exhausts, they almost touch.. Stuff the combustion chamber full of piston dome, upwards of 12.5 - 13:1.. .500 lift. 300 - 310 actual duration and lots of overlap to aid scavenging.. Finish it off with the best rods money can buy.. Gear it to run 7900 - 8300 (8500 - 8600 on occasion) at the end of the straightaway, you'll definitely need some good valve springs to do this.. The cams I used back in those days were Reed Cams, ground specifically for short dirt tracks..

[franken]

You can get a cheap borescope for about $20, which is a lot less than reinstalling the heads.
Chances are pretty good that a crate 350 will cost less than rebuilding the 283.
Around here we have selfserve scrapyards where decent used 350s are cheap.

[MikeB]

Originally Posted by Backpayne

I'm just taking the heads off and oil pan to clean it out and replace the gaskets. There's some sludge in the heads and I want to make sure the oil pickup is clean. If the cylinders are scored I'm going to get a different engine.

No telling what you might find in the cylinders if the engine sat in the rain.

But if they are OK, you should also check the rod and main bearings while you have good access.

[AcampoDave]

Originally Posted by franken

You can get a cheap borescope for about $20, which is a lot less than reinstalling the heads.
Chances are pretty good that a crate 350 will cost less than rebuilding the 283.
Around here we have selfserve scrapyards where decent used 350s are cheap.

My local parts store (Autozone) will loan a borescope with a deposit

[Dead Parrot]

One advantage of a 283 is fuel economy. A 283 matched with an Impala often got 20~22 mpg. And Impalas of that era were not small cars. Sometimes it is fun to wave at the guy with the 383 + wild cam pulling into yet another gas station while you cruise on by. Don't be in a hurry to ditch your 283.

BTW - the truck itself looks pretty good from the view provided.

[MikeB]

Originally Posted by Dead Parrot

Don't be in a hurry to ditch your 283.

I agree. There's a lot to be said for originality, and there's absolutely no reason why a 283 wouldn't work just fine in that truck.

I'd certainly try to get it running before going the cookie cutter 350 route. I'm allowed to say that because my 69 truck has a 350! But I sometimes wish I would have kept the 307. That 307 really woke up after I replaced the cam, noisy lifters, and timing chain (less than $100 back in 1990) and added a 450cfm 4bbl and dual exhausts. But it had >100K miles on it, so I used that excuse a year later to buy a crate 350.

With a fresh bore and better heads, the 307 would have been better than new.

[AcampoDave]

Originally Posted by MikeB

I agree. There's a lot to be said for originality, and there's absolutely no reason why a 283 wouldn't work just fine in that truck.

I'd certainly try to get it running before going the cookie cutter 350 route. I'm allowed to say that because my 69 truck has a 350! But I sometimes wish I would have kept the 307. That 307 really woke up after I replaced the cam, noisy lifters, and timing chain (less than $100 back in 1990) and added a 450cfm 4bbl and dual exhausts. But it had >100K miles on it, so I used that excuse a year later to buy a crate 350.

With a fresh bore and better heads, the 307 would have been better than new.

Small V/8's can be a lot of fun when you really get them dialed in. They are fast enough to be fun, but modest enough to still not be so dangerous when you push them to their limit on the open road. I'm one of those guys who is not restrained enough for anything over 250 h.p in my hot rod. After all, a 200+ h.p 283, 307 or even a 305 IS a hottrodded engine, but a 200 h.p. 350 is...well.....stock.

[Backpayne]

I found some scratches in the walls of two cylinders that I can feel with my fingernail. Does this require a trip to the machine shop? If so it will be a trip to the scrap yard.

[Dead Parrot]

How are the bore measurements? If in the acceptable range, pull the pistons, hone the cylinders, install new rings and run. For a cruising motor, don't worry too much about a couple of minor scratches in 2 cylinders.

While the heads are off, install some new valve seals and consider a basic valve job.

[Backpayne]

Originally Posted by Dead Parrot

How are the bore measurements? If in the acceptable range, pull the pistons, hone the cylinders, install new rings and run. For a cruising motor, don't worry too much about a couple of minor scratches in 2 cylinders.

While the heads are off, install some new valve seals and consider a basic valve job.

What is the best tool to use for measuring bore measurements? I don't have any micrometer, but I'm not opposed to buying a new tool!

[GASoline71]

Originally Posted by AcampoDave

As detective Columbo used to say..."There is one more thing",....if you plan on using a squarebore carb like an Edelbrock, look at the Performer EPS since it's made specifically for that application. That way you can avoid the old Quadrajet style manifold plenum.

The EPS is such an underrated intake manifold. I had one on a 350 in a '79 K25 with a Holley 1850 600 CFM carb and had a cam profile ground from a local cam shop that matched the Comp XE268, and it made great power with good low-end grunt.

Gary

[Backpayne]

Originally Posted by Dead Parrot

How are the bore measurements? If in the acceptable range, pull the pistons, hone the cylinders, install new rings and run. For a cruising motor, don't worry too much about a couple of minor scratches in 2 cylinders.

While the heads are off, install some new valve seals and consider a basic valve job.

Just bought a cylinder bore gauge and it will come in Friday. Which kind of bor hone do you recommend? The dingleberry kind or the three stone kind?

[AcampoDave]

What about the wear ridge at the tops of the bores. Will the piston fit thru or will you need a tool to ream those?
Maybe your local auto parts chain store loans those.

[Tom]

Originally Posted by theastronaut

Vortec heads will need center bolt valve covers in addition to a Vortec specific intake. The valves will be shrouded in a small bore 283 and compression will drop so they won’t flow as well as they would on a 4” bore, and the improved chamber design is kinda wasted at a lower compression point.

Your talking 350 vortec heads. I refferred to 305 versions. Smaller chamber, smaller valves, vortec ports.

[Willshook]

Originally Posted by AcampoDave

What about the wear ridge at the tops of the bores. Will the piston fit thru

Cast pistons are fit VERY tight - often .0005 +.0005/-0 - and pounding them past the ridge will break the rings, likely break the ring lands, and score the piston skirts.

Ridge reamers leave a pretty rough edge with the expectation that the cylinder is getting bored and/or honed (not surface honed) and the pistons replaced, so a very light touch is required if no machine work is being done.

[Willshook]

Originally Posted by Backpayne

Just bought a cylinder bore gauge

Note that you still need a micrometer, which you noted you don't have, to zero the bore gauge.

Bores can be measured with a snap gauge/micrometer or an inside micrometer; a bore gauge is used to easily measure how the entire bore varies from a set measurement to find piston/crank-to-bore clearance and cylinder out-of-round, taper, etc. to plan boring.