Crack/Knick in 350 Cylinder Wall

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

SMC2224

Junior Member
Joined
Apr 26, 2024
Posts
8
Reaction score
10
Location
Indiana
First Name
Skyler
Truck Year
1977
Truck Model
K30 Crew Cab
Engine Size
350
This block sat uncovered last winter and was full of water/antifreeze. I’ve torn it down and noticed this crack or knick in the cylinder wall. What do you guys think? It appears to be a Knick to me because one side is higher than the other. A crack would tend to be somewhat flush with a tiny gap? The pistons were seized in there really bad and took some banging to get out. Is this something honing could fix or is this block trash? Zero engine experience btw
 

Attachments

  • IMG_3507.jpeg
    IMG_3507.jpeg
    144.8 KB · Views: 52

Magna86

Full Access Member
Joined
Mar 1, 2021
Posts
134
Reaction score
287
Location
VA Beach
First Name
Magna86
Truck Year
1976
Truck Model
Silverado
Engine Size
Chevy 350
Thats now a boat anchor. Thats a crack and needs sleeved but most wont spend that money on a 350.
 

SMC2224

Junior Member
Joined
Apr 26, 2024
Posts
8
Reaction score
10
Location
Indiana
First Name
Skyler
Truck Year
1977
Truck Model
K30 Crew Cab
Engine Size
350
Thats now a boat anchor. Thats a crack and needs sleeved but most wont spend that money on a 350.
Do I have to sleeve all 8 or just the one that’s cracked? It’s bored .30 over right now so would a machine shop bore it over the thickness of the sleeve so that the .030 pistons will fit or does it get sleeved back down to stock of 4.00” bore?
 

Bennyt

Full Access Member
Joined
May 17, 2019
Posts
1,201
Reaction score
1,850
Location
Surprise
First Name
Ben
Truck Year
1977
Truck Model
C10
Engine Size
350
I wouldn't toss it yet. 350 blocks are scarce. When I worked at PAW in the late 90's, cores were drying up and we started putting in 8 sleeves and making std bore blocks. It was actually a $100 upgrade as the sleeves were substantially stronger and consistent thickness.
 

Bennyt

Full Access Member
Joined
May 17, 2019
Posts
1,201
Reaction score
1,850
Location
Surprise
First Name
Ben
Truck Year
1977
Truck Model
C10
Engine Size
350
Do I have to sleeve all 8 or just the one that’s cracked? It’s bored .30 over right now so would a machine shop bore it over the thickness of the sleeve so that the .030 pistons will fit or does it get sleeved back down to stock of 4.00” bore?
You'll have to sleeve the one and probably bore the entire block 0.060
 

SMC2224

Junior Member
Joined
Apr 26, 2024
Posts
8
Reaction score
10
Location
Indiana
First Name
Skyler
Truck Year
1977
Truck Model
K30 Crew Cab
Engine Size
350
You'll have to sleeve the one and probably bore the entire block 0.060
I’m sorry, this doesn’t make a lick of sense to me. If I put a sleeve of let’s say 3/32” or .09375”. The bore is now 4.030 - .09375” = 3.93625” in that cylinder while the rest are still 4.030”. Are you saying bore .060” from there? So 3.93625+.06 = 3.99625”? Or bore all 8 cylinders to 4.060”? Cause if that’s the case wouldn’t that just bore through the crack? Why put a sleeve in there if it’s gonna be bored away? Thoroughly lost how the bore could increase after sleeving? Unless I don’t understand how sleeves work but I was under the impression it just sat in the old cylinder wall
 

Bennyt

Full Access Member
Joined
May 17, 2019
Posts
1,201
Reaction score
1,850
Location
Surprise
First Name
Ben
Truck Year
1977
Truck Model
C10
Engine Size
350
You have to bore the block like .250 and then the sleeve is press fit in. Basically cutting away the old material Then you bore the sleeve to match the existing cylinders. You stated existing is 0.030 but based on what I am seeing, I am going to assume all the cylinders will need to be bored during a rebuild.

And don't worry about sleeves. Substantially stronger than stock, used in diesels. Plenty of matching numbers blocks saved with sleeves.
 

SMC2224

Junior Member
Joined
Apr 26, 2024
Posts
8
Reaction score
10
Location
Indiana
First Name
Skyler
Truck Year
1977
Truck Model
K30 Crew Cab
Engine Size
350
You have to bore the block like .250 and then the sleeve is press fit in. Basically cutting away the old material Then you bore the sleeve to match the existing cylinders. You stated existing is 0.030 but based on what I am seeing, I am going to assume all the cylinders will need to be bored during a rebuild.

And don't worry about sleeves. Substantially stronger than stock, used in diesels. Plenty of matching numbers blocks saved with sleeves.
Thank you, that makes much more sense. Do you know what going price is for sleeving and boring so I got an idea? Thanks
 

Bennyt

Full Access Member
Joined
May 17, 2019
Posts
1,201
Reaction score
1,850
Location
Surprise
First Name
Ben
Truck Year
1977
Truck Model
C10
Engine Size
350
No idea on price. Haven't had a block bored in years and rates vary greatly on location and shop. I got 2 quotes to get a crank ground this week. One shop was $125 and the other was $220.
 

idahovette

Full Access Member
Joined
Aug 7, 2016
Posts
7,269
Reaction score
15,871
Location
Weiser Idaho
First Name
Perry
Truck Year
1975-1979
Truck Model
K20-K10
Engine Size
350
Thank you, that makes much more sense. Do you know what going price is for sleeving and boring so I got an idea? Thanks
You are gonna have to do some of your own homework, shop prices vary through out the land
 

Craig Nedrow

NADAR UNDER THE RADAR
Supporting Member
Joined
Sep 1, 2018
Posts
1,036
Reaction score
2,183
Location
Washington State
First Name
Craig
Truck Year
1973 (have two), 1985
Truck Model
K10, K20, C20
Engine Size
350, 454, 6.2 Detroit
I have sleeved quite a few blocks for different reasons, never had a problem. The procedure is:
get the right sleeve, if the other bores are in tolerance and just need a hone, you are good to go. We had chevy sleeves always in stock. Anyway while I have seen others bore until they get into the water jackets for really thick sleeves for a blown application, (Check out LA Sleeve), we would bore the block so the finished sleeve would have at least .0625 wall thickness. I would leave a shoulder on the bottom for the sleeve to bottom out on. Care must be taken when getting close to the bottom with the sleeve that you did not break that, as we used a 10 lb sledge hammer to drive it in. You will here it when it hits bottom. Then bore out to within .002 and hone out to spec. I am sure there will be nay sayers, but it has worked well for me. Note, freeze the sleeve B4 install, follow the mfg recommendations for bore press. Here is a short video of a block I bored.

xc_hide_links_from_guests_guests_error_hide_media
 

JBswth

Full Access Member
Joined
Jan 24, 2022
Posts
225
Reaction score
182
Location
Vallejo, California
First Name
James
Truck Year
1973
Truck Model
C25
Engine Size
292 cubic inches
This block sat uncovered last winter and was full of water/antifreeze. I’ve torn it down and noticed this crack or knick in the cylinder wall. What do you guys think? It appears to be a Knick to me because one side is higher than the other. A crack would tend to be somewhat flush with a tiny gap? The pistons were seized in there really bad and took some banging to get out. Is this something honing could fix or is this block trash? Zero engine experience btw
That is a crack. A score would be straight. You can have it sleeved, but first mike the other cylinders. If they are already at maximum oversize, you will have to decide if you want to sleeve all the cylinders. Not cheap, but 350s are becoming less than common, so think about it.

J. B.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
5,446
Reaction score
8,679
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
Check the rest of the block,very,very carefully for cracks. Block left out all winter, uncovered,I would assume water got in and froze,causing that crack. But wouldn't be surprised to find a cracks in the lifter gallery area,where most people wouldn't think to look. Anywhere where water could get in and freeze,is a potential cracks are. Blind bolt holes, any direction around a water jacket,or oil passage. Also a little tip for you and any newb on assemble make sure any blind bolt holes are clean and dry liquid or grease can get in blind bolt holes and as you are tightening a bolt create hydraulic pressure and crack or even pop part of a block off. @Craig Nedrow hadn't heard the name L.A sleeve forever we used them like 90s ish. Are they still around?
 
Last edited:

Rickf

Full Access Member
Joined
Jul 29, 2017
Posts
571
Reaction score
713
Location
Grafton NH
First Name
Rick
Truck Year
1974, 1954 & a 1937
Truck Model
K20
Engine Size
350
I vote for a future boat anchor. Don't waste your time or money on it, look for a re-man from summit racing or similar retailer.
 

Latest posts

Forum statistics

Threads
44,157
Posts
950,592
Members
36,271
Latest member
jstewart7501
Top