How can I tell if I have a warped block?
10-15-2004, 01:35 PM
#1
Supreme Member
Thread Starter
iTrader: (2)
Join Date: Jul 2001
Location: Western PA
Posts: 1,000
Likes: 0
Received 1 Like
on
1 Post
Car: 1986 IROC-Z
How can I tell if I have a warped block?
I'm (still) rebuilding my engine. The heads have been decked, but I recently ran into an external coolant leak through the head gasket whenever I reassembled the motor. I haven't pulled the heads yet to determine where it's leaking from, but I suspect that it may be coming through an improperly-sealed head bolt. If that's not the case, then the only other possibility that I can think of is a warped block.
The engine was overheated two years ago, so I know it's a possibility. A blown head gasket is also the reason why I decided to rebuild the motor in the first place. I told my machinist to deck the block when he had it, but he never did it. I overlooked that and never noticed until I was reviewing some pictures I took during assembly.
Is there an easy way for me to check if the block is warped with the engine still in the car? I had thought about using a straightedge with a light behind it, noting how much light entered through any gaps. Can I do it a better way?
The engine was overheated two years ago, so I know it's a possibility. A blown head gasket is also the reason why I decided to rebuild the motor in the first place. I told my machinist to deck the block when he had it, but he never did it. I overlooked that and never noticed until I was reviewing some pictures I took during assembly.
Is there an easy way for me to check if the block is warped with the engine still in the car? I had thought about using a straightedge with a light behind it, noting how much light entered through any gaps. Can I do it a better way?
10-16-2004, 02:45 AM
#2
Supreme Member
iTrader: (1)
Join Date: May 2004
Location: houston
Posts: 2,262
Likes: 0
Received 0 Likes
on
0 Posts
Car: 83 POS monte carlo 2015 chevy P/U
Engine: 92 5.7 tpi 5.3
Transmission: 700r4 6L60E
Axle/Gears: 2.42 too high
that will work, but to get an accurate measurement use a feeler gage. if you have a a repair manual it should have specs in it for how much is too much.
10-16-2004, 04:19 AM
#3
TGO Supporter
precission straight edge and feeler gage, should be less than .005 or so out of flat. i'd say someone really dropped the ball if you wanted the block decked and never got it done at the shop and if you never noticed it when you got it. i always have a block surfaced at the very least when it's at the machine shop. if it's leaking without running i'd guess you have a big problem. did you use sealer on the head bolts?
10-16-2004, 10:23 PM
#4
Supreme Member
Thread Starter
iTrader: (2)
Join Date: Jul 2001
Location: Western PA
Posts: 1,000
Likes: 0
Received 1 Like
on
1 Post
Car: 1986 IROC-Z
Yep, it's leaking when the engine's off. Not as bad as when it's on, but it's still occurring. I don't actually get a puddle when the car is running because the coolant burns right off, but if I let it sit while warm it'll pool up. When cold, the coolant kinda oozes out.
Yep, I used thread sealant on the bolts. They're brand new bolts that came with sealant already on the threads... fairly thick, too.
I pulled the head today and I cannot find one trace of anything bad on either the head, the block, or the gasket. Everything looks just fine; the head gasket looks properly compressed, too. I did find that the head bolt closest to the leak was one of the easier bolts to remove, but that may have been because I removed them in the order I put them on (standard SBC pattern). I'm positive that I torqued them down evenly; I'm a nut about that and triple-checked. The Fel-Pro gasket I used also stated that re-torquing was not necessary, so I don't think the bolt backed out or anything.
Yep, I used thread sealant on the bolts. They're brand new bolts that came with sealant already on the threads... fairly thick, too.
I pulled the head today and I cannot find one trace of anything bad on either the head, the block, or the gasket. Everything looks just fine; the head gasket looks properly compressed, too. I did find that the head bolt closest to the leak was one of the easier bolts to remove, but that may have been because I removed them in the order I put them on (standard SBC pattern). I'm positive that I torqued them down evenly; I'm a nut about that and triple-checked. The Fel-Pro gasket I used also stated that re-torquing was not necessary, so I don't think the bolt backed out or anything.
10-17-2004, 07:56 AM
#5
TGO Supporter
shin or coated gasket? to leak cold you either did something wrong or have a problem. the fact that it over heated would lead me to suspect a crack or warpage.
Trending Topics
10-19-2004, 01:20 PM
#8
Supreme Member
Thread Starter
iTrader: (2)
Join Date: Jul 2001
Location: Western PA
Posts: 1,000
Likes: 0
Received 1 Like
on
1 Post
Car: 1986 IROC-Z
I used Fel-Pro blue Permatorque head gaskets... I guess that would be a coated gasket? They were definitely not flimsy metal like some that I've seen.
The machinist told me that the block was magnafluxed and that there were no cracks... but I didn't actually see him do it.
The frost plugs are all new, but I looked at them and I never saw any leakage. The plugs look fine, too. I don't think that any coolant was entering the cylinders.
The machinist told me that the block was magnafluxed and that there were no cracks... but I didn't actually see him do it.
The frost plugs are all new, but I looked at them and I never saw any leakage. The plugs look fine, too. I don't think that any coolant was entering the cylinders.
10-19-2004, 01:46 PM
#9
Supreme Member
Thread Starter
iTrader: (2)
Join Date: Jul 2001
Location: Western PA
Posts: 1,000
Likes: 0
Received 1 Like
on
1 Post
Car: 1986 IROC-Z
I took a few pictures of the head gasket. By letting them sit (dry out?) for a few days, coolant marks are now visible. This is a shot of the gasket at the location where the engine was leaking. It looks like the lower water jacket may be the culprit.
A shot of the head at the same location.
Finally, the block. It sure doesn't appear decked, does it?
I guess this rules out any possibility of a leaky head bolt. Could a warped block still make a gasket leak here, or is there a better chance of mechanic's (my) error? I also took a picture of another cylinder at the same water jacket. What is that black border around the compressed portion of the gasket? Is that coolant seeping out around the base? Notice how it appears to stretch into the cylinder. I was able to wipe the fire ring clean, but the head gasket remains dirty. The black thing on top of the water jacket area is just a piece of dirt; it wasn't on the gasket when I pulled it apart.
A shot of the head at the same location.
Finally, the block. It sure doesn't appear decked, does it?
I guess this rules out any possibility of a leaky head bolt. Could a warped block still make a gasket leak here, or is there a better chance of mechanic's (my) error? I also took a picture of another cylinder at the same water jacket. What is that black border around the compressed portion of the gasket? Is that coolant seeping out around the base? Notice how it appears to stretch into the cylinder. I was able to wipe the fire ring clean, but the head gasket remains dirty. The black thing on top of the water jacket area is just a piece of dirt; it wasn't on the gasket when I pulled it apart.
Last edited by blue86iroc; 10-19-2004 at 01:48 PM.
07-18-2019, 10:26 AM
#10
Junior Member
Join Date: Jul 2019
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
Re: How can I tell if I have a warped block?
I'm (still) rebuilding my engine. The heads have been decked, but I recently ran into an external coolant leak through the head gasket whenever I reassembled the motor. I haven't pulled the heads yet to determine where it's leaking from, but I suspect that it may be coming through an improperly-sealed head bolt. If that's not the case, then the only other possibility that I can think of is a warped block.
The engine was overheated two years ago, so I know it's a possibility. A blown head gasket is also the reason why I decided to rebuild the motor in the first place. I told my machinist to deck the block when he had it, but he never did it. I overlooked that and never noticed until I was reviewing some pictures I took during assembly.
Is there an easy way for me to check if the block is warped with the engine still in the car? I had thought about using a straightedge with a light behind it, noting how much light entered through any gaps. Can I do it a better way?
The engine was overheated two years ago, so I know it's a possibility. A blown head gasket is also the reason why I decided to rebuild the motor in the first place. I told my machinist to deck the block when he had it, but he never did it. I overlooked that and never noticed until I was reviewing some pictures I took during assembly.
Is there an easy way for me to check if the block is warped with the engine still in the car? I had thought about using a straightedge with a light behind it, noting how much light entered through any gaps. Can I do it a better way?
The following users liked this post:
WildCard600 (07-18-2019)
Thread
Thread Starter
Forum
Replies
Last Post
skinny z
Engine/Drivetrain/Suspension Parts for Sale
5
10-05-2015 06:23 PM
