Looking for engine rebuild advice 1958 283/250

[Arthur T.]

I'm starting engine rebuild, short block first.

I have the original 283, crank, pistons, rods, camshaft and timing chain.

block : cylinders #1 and #8 are worn and will likely compel a .020 overbore. I am optimistic that we will not have to deck the block, but my machine shop hasn't made the call on that yet.

crank : looks like it needs to be ground at least 010 and possibly 020. Obviously we will be doing new main bearings and seals. Recommendations?? Clevite? others?

camshaft is worn and I plan to replace with either Sealed Power CS-274 or Melling CCS-2. I plan to use Durabond camshaft bearings unless someone convinces me there are better alternatives.

timing chain and gears are original and well worn. I plan to replace these with a modern roller chain and gears. Any recommendations?

rods and pistons were not stored properly. Several are corroded, but I also have 4 NOS pistons that are 40 years old.
Regardless of what shape the rods are in, my inclination is to replace them with Eagle SIR5700SLWP rods. Are there any opinions about this?
Should the pistons be replaced as a set? I think yes. Any recommendations?
Rings need replacement, likely 020 over. Any suggestions as to which manufacturer?
Rod bearings : These will get replaced. With what is the question. Any suggestions?


thanks for all opinions.

[Joe L.]

Re: Looking for engine rebuild advice 1958 283/250

I'm starting engine rebuild, short block first.

I have the original 283, crank, pistons, rods, camshaft and timing chain.

block : cylinders #1 and #8 are worn and will likely compel a .020 overbore. I am optimistic that we will not have to deck the block, but my machine shop hasn't made the call on that yet.

crank : looks like it needs to be ground at least 010 and possibly 020. Obviously we will be doing new main bearings and seals. Recommendations?? Clevite? others?

camshaft is worn and I plan to replace with either Sealed Power CS-274 or Melling CCS-2. I plan to use Durabond camshaft bearings unless someone convinces me there are better alternatives.

timing chain and gears are original and well worn. I plan to replace these with a modern roller chain and gears. Any recommendations?

rods and pistons were not stored properly. Several are corroded, but I also have 4 NOS pistons that are 40 years old.
Regardless of what shape the rods are in, my inclination is to replace them with Eagle SIR5700SLWP rods. Are there any opinions about this?
Should the pistons be replaced as a set? I think yes. Any recommendations?
Rings need replacement, likely 020 over. Any suggestions as to which manufacturer?
Rod bearings : These will get replaced. With what is the question. Any suggestions?


thanks for all opinions.

Arthur-----

1) I doubt the block will need to be surfaced. This is rarely necessary for blocks but is sometimes done by machine shops as a matter of "routine".

2) For bearings I prefer premium aluminum to tri-metal but the tri-metal are OK. Federal-Mogul has premium aluminum bearings ("AP" suffix). GM bearings are premium aluminum;

3) Durabond cam bearings are the best; go with them.

4) Never re-use timing set components during a rebuild. I recommend using Cloyes Tru Roller 9-3100;

5) I would use the Eagle rods. Original 283 rods are somewhat weak although probably adequate. As an economical alternative, find a set of reconditioned GM #3864881 rods. These were used for later 327's and will be just fine for your application. They are considerably improved over the 283 and early 327 rods;

6) I would only replace pistons as a set. KB or Federal Mogul hypereutectic cast are the way to go.

7) For rings I would use moly-filled top ring, cast iron second ring, and chrome/stainless oil control rings. Perfect Circle or Total Seal;

8) For rod bearings it's the same as main bearings----I prefer premium aluminum from Federal Mogul or GM (most of the GM bearings now are Federal-Mogul-manufactured premium aluminum). As before, Clevite tri-metal are OK.

[Timothy B.]

Re: Looking for engine rebuild advice 1958 283/250

Arthur,

If it's a corvette block aren't there suffix numbers on the stamp pad. If so, I would insist no decking be done on the block as you will wipe away those stampings. My suggestion is the least overbore as possible even if you have to order the pistons and wait for them to arrive.

Don't use any hot rod parts, stay away from high pressure oil pumps etc.

[Clem Z.]

Re: Looking for engine rebuild advice 1958 283/250

if you do not deck the block used a shop that does not mount the boring bar to the top of the block as this could cause a the bores to be not perpendicular to the crank center line

[David K.]

Re: Looking for engine rebuild advice 1958 283/250

I insisted, that they NOT deck my block, unless they talked to me first. They didn't call and my original block is well.

[Duke W.]

Re: Looking for engine rebuild advice 1958 283/250

I'd look for a serviceable 327 crank, which would make it a 307 plus what the overbore adds. Plus consider massaging heads. Then you can make good use of the McCagh Special camshaft.

Duke

[Arthur T.]

Re: Looking for engine rebuild advice 1958 283/250

Arthur,

If it's a corvette block aren't there suffix numbers on the stamp pad. If so, I would insist no decking be done on the block as you will wipe away those stampings. My suggestion is the least overbore as possible even if you have to order the pistons and wait for them to arrive.

Don't use any hot rod parts, stay away from high pressure oil pumps etc.

I am 100% certain this is the original corvette block. I have the car ownership history all the way back to 1963, easy, since I bought it in 1975. The stamp pad has F606CR on it. The block was cast F-3-8. The car was assembled 6-20-58. This block was in this car in 1963.

I plan to resist any decking. If my machine shop recommends it, I will hold the job while I investigate further.

[Arthur T.]

Re: Looking for engine rebuild advice 1958 283/250

I am reluctant to mess with the heads. 770 heads are a b*tch to get these days and I have a matched pair for this car, E278, one each from mold cavities 1 & 2. You don't get more matched than that.

Tell me why I would want to do this for an NCRS restoration. I am open to suggestions and new info. I realize that externally, there would be no visible difference. There must be some other reliability or performance gains that justify these modifications.

[Timothy B.]

Re: Looking for engine rebuild advice 1958 283/250

Arthur,

If it's the original block absolutely no decking, I think a 327 crankshaft will require some relief work to the bottom of the block so stay away from that$$$. Either find a nice standard 283 crankshaft or have yours turned as little as possible after checking for straightness and cracks. Keep your rod and main clearances to the tighter GM spec, on a 327 .002 is good and it's probably the same on 283.

I agree with you completely on the heads, just do a stock overhaul including a stock timing set with new crank and cam gears. Have the machine shop check the crankshaft to camshaft distance as this will ensure no timing chain slop. The rods are the only thing that need updating to the later 1966/67 style with the extra metal around the bolt seats.

Clem's advice above is noteworthy with regard to boring the block so be careful that it's done properly, I am not sure if they locate the boring bar half way down the cylinder or have a machine that locates 90*off crankshaft centerline. Final hone with deck plate and main caps after the new pistons arrive and are measured.

Take the time to assemble the motor measuring deck clearance rod side clearance and move the pistons/rods around to your advantage before assembly. Select a head gasket (thin) that will keep the compression up where it's supposed to be and I think you will have a nice running engine, try to find a GM steel head gasket for a 283.