Tore the motor down today.
Thread Starter
Melting Slicks
Joined: Dec 2000
Posts: 2,198
Likes: 2
From: Eastern Connecticut
Tore the motor down today.
I have finally stripped the motor that spun a rod bearing last year. #1 rod bearing spun, taking the crank out. #1 main looked pretty bad, too, some pieces must have gotten into it. So, I'll be replacing the crank.
The motor is .040 over, but there is almost no ridge, so .060 will do it. The cylinders are pretty beat up, looks like the pistons were rocking. Should I have any problem going .060 on a 73 L48 block? It's the matching numbers block so I want to use it.
Secondly, can anyone ID the cam? It is stamped 10-03R on the back. It's probably a generic L48 cam, but maybe not? The cam blank has at various places cast markings as follows: D2; 21; G; CWC and EP 6. I'm just curious, as I decided on the new Crane H-262, and don't want to go backwards in power.
Thanks for the help.
Joe
The motor is .040 over, but there is almost no ridge, so .060 will do it. The cylinders are pretty beat up, looks like the pistons were rocking. Should I have any problem going .060 on a 73 L48 block? It's the matching numbers block so I want to use it.
Secondly, can anyone ID the cam? It is stamped 10-03R on the back. It's probably a generic L48 cam, but maybe not? The cam blank has at various places cast markings as follows: D2; 21; G; CWC and EP 6. I'm just curious, as I decided on the new Crane H-262, and don't want to go backwards in power.
Thanks for the help.
Joe
Race Director
Joined: Jan 2003
Posts: 15,176
Likes: 87
From: State of Confusion
Joe:
can't offer any help on going .060"-over on the '73 block:
I don't know if the early-'70s blocks were any 'beefier' than the later blocks, but I doubt it'd be worse...
As far as the camshaft, you might be able to use micrometers on it, to establish what the lift is, based off of the base-circle diameter
(mic the tallest part of the lobe, then mic 90* to that).
If you can establish the lift spec, you may/may-not rukle-out the OEM L-48 cam.
Just a thought.....
can't offer any help on going .060"-over on the '73 block:
I don't know if the early-'70s blocks were any 'beefier' than the later blocks, but I doubt it'd be worse...
As far as the camshaft, you might be able to use micrometers on it, to establish what the lift is, based off of the base-circle diameter
(mic the tallest part of the lobe, then mic 90* to that).
If you can establish the lift spec, you may/may-not rukle-out the OEM L-48 cam.
Just a thought.....
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Originally Posted by joe73vette
I have finally stripped the motor that spun a rod bearing last year. #1 rod bearing spun, taking the crank out. #1 main looked pretty bad, too, some pieces must have gotten into it. So, I'll be replacing the crank.
The motor is .040 over, but there is almost no ridge, so .060 will do it. The cylinders are pretty beat up, looks like the pistons were rocking. Should I have any problem going .060 on a 73 L48 block? It's the matching numbers block so I want to use it.
Secondly, can anyone ID the cam? It is stamped 10-03R on the back. It's probably a generic L48 cam, but maybe not? The cam blank has at various places cast markings as follows: D2; 21; G; CWC and EP 6. I'm just curious, as I decided on the new Crane H-262, and don't want to go backwards in power.
Thanks for the help.
Joe
The motor is .040 over, but there is almost no ridge, so .060 will do it. The cylinders are pretty beat up, looks like the pistons were rocking. Should I have any problem going .060 on a 73 L48 block? It's the matching numbers block so I want to use it.
Secondly, can anyone ID the cam? It is stamped 10-03R on the back. It's probably a generic L48 cam, but maybe not? The cam blank has at various places cast markings as follows: D2; 21; G; CWC and EP 6. I'm just curious, as I decided on the new Crane H-262, and don't want to go backwards in power.
Thanks for the help.
Joe
Now that cam must be a aftermarket piece as the stock casting would have cast GM raised letters, a raised diamond and rectangle on bearing race nest to last (near dist gear). So I can't say if the Crane piece will be an improvement but my guess is it will be just fine for street performance. BTW the stock 350" cam part #s are 3896929 for the 190 hp motor and 3896962 for the 250 hp.
You have a lot of work ahead of you Joe so I hope this helps. Good night.
cardo0
Pro
Joined: Oct 2002
Posts: 708
Likes: 0
From: somewhere south of normal
The $600 question is how much is that original block worth to ya? Sleeving a thin or bad cyl I'm guessing is about $200 a hole and a good machinist/shop should be able to tell if sleeving needed.
Sleeving should run about $40.00 per sleeve.
I would just put the original bolck in the corner and start fresh. SBC blocks are plentiful.
Sleeving should run about $40.00 per sleeve.
I would just put the original bolck in the corner and start fresh. SBC blocks are plentiful.
Le Mans Master
Joined: Mar 2004
Posts: 7,493
Likes: 1,500
From: Little Rock AR
You do not want to sleeve it. If you DO sleeve it, your machinist will need to deck the block and all the numbers you are trying to save will go away. It would be correct casting number and date but the magic VIN number would be gone. You could document it carefuly and then sleeve it but if it were me, I would have it sonic checked to see if it can go .060" over. If not, mothball the original block and find a better core.
-Mark.
-Mark.
Thread Starter
Melting Slicks
Joined: Dec 2000
Posts: 2,198
Likes: 2
From: Eastern Connecticut
I will be bringing the block to a shop but wanted to be informed before then. I don't think I will be sleeving it, it's really not worth it. If I do need another block, it'll be a newer roller cam motor. But then I'll have two old blocks taking up space in my garage, the original vette motor and the impala motor currently in it.
OBTW, the cam mic'd out at .380 lift at the valves, a little less than the stock L48 cam. It's probably a jobber replacement cam. The crane cam has .446/.459 lift so it should reallly wake the motor up, especially with vortec heads.
Joe
OBTW, the cam mic'd out at .380 lift at the valves, a little less than the stock L48 cam. It's probably a jobber replacement cam. The crane cam has .446/.459 lift so it should reallly wake the motor up, especially with vortec heads.
Joe
Last edited by joe73vette; Aug 1, 2004 at 01:03 PM.
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
First ask yourself what kind of performance you are looking for, you can get a GM long block for under $1500 and with a cam swap have about 300-320 hp, you would be hard pressed to have your low end re-done for that. You can get little better short block for $1500 too if you look around.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
.060 is OK
No problem with the overbore. As for a cam, the good ol' G.M. '962' cam is great for mild powerups. I used it on my last 350 and it made power all the way to 6k RPM even with just a performer manifold.
When I put this stroker in the Vette, I should have used it ... the crane I'm using now runs outta steam at 5,000.
When I put this stroker in the Vette, I should have used it ... the crane I'm using now runs outta steam at 5,000.
Thread Starter
Melting Slicks
Joined: Dec 2000
Posts: 2,198
Likes: 2
From: Eastern Connecticut
Originally Posted by SanDiegoPaul
No problem with the overbore. As for a cam, the good ol' G.M. '962' cam is great for mild powerups. I used it on my last 350 and it made power all the way to 6k RPM even with just a performer manifold.
When I put this stroker in the Vette, I should have used it ... the crane I'm using now runs outta steam at 5,000.
When I put this stroker in the Vette, I should have used it ... the crane I'm using now runs outta steam at 5,000.
