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SB400 progress

mountainexplorer

mountainexplorer

1/2 ton status
Joined
Nov 14, 2001
Posts
4,904
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6
Location
Spokane, Wa./Ione, Wa
It WILL run tomorrow. This has taken me WAY too much time to get together and in.

I'm hoping it runs good. I don't really trust my work.

http://community.webshots.com/photo/28668497/161803048hKPknU

http://community.webshots.com/photo/28668497/161805279akrGYJ

http://community.webshots.com/photo/28668497/161803147oNyjZW

http://community.webshots.com/photo/28668497/161803515QsekkD

http://community.webshots.com/photo/28668497/161803646sWQler

It's a small block 400, bored .040 over, hypereutectic flattop pistons, 041 casting semi-closed chamber heads, 1.94s, Z28 springs, Comp 292 duration, .510 lift cam, screw in studs and guide plates, roller rockers, Cloyes Gear drive, Edelbrock Performer RPM Intake and 625 Edelbrock carb.
 
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Awesome! How long did it take from teardown to final reassembly? I've got a 400 I'm itching like hell to build. /forums/images/graemlins/peace.gif
 
Only a YEAR and I started with a longblock. /forums/images/graemlins/eek.gif

Probably one of the motors thats taken me the longest. Considering I'm too cheap to buy new parts, and it takes forever for me to deal with finding all the stuff I DO have thats just hiding.

It was a rebuild longblock I got from a friend. I took the heads off and had the 041 heads rebuilt through a friend of mine (some trading), traded the RV cam in it for the 292 cam, used the gear drive from another motor, and all the accessory stuff I've been accumulating for a while.

I DID however have to break down and buy a gasket set.

I started from a shortblock on Thursday night, and got to the point of running today. Most of that time (hours) was spent stumbling around my garage trying to find bolts or gaskets that kept eluding me. Plus, if you saw my tool selection, you'd understand why it takes so long.

I'm just about used to being able to do everything with one crescent wrench.

I just drove it to the gas station and back... its tempting to just open it up and see what it's got, but I don't want to push my luck with the law. The muffler shop will be open in the morning. I'll have to wait until then.
 
[ QUOTE ]

It's a small block 400, bored .040 over,

[/ QUOTE ]
That bothers me, those walls are getting very thin. I have been told by a LOT of people that .030" is max for a street 400 because anything larger and reliability will be an issue and some overheating problems could become an issue.

But take that as you will, it's your motor.

You will like the 400, big block like low end torque with sb revving.
 
[ QUOTE ]
[ QUOTE ]

It's a small block 400, bored .040 over,

[/ QUOTE ]
That bothers me, those walls are getting very thin. I have been told by a LOT of people that .030" is max for a street 400 because anything larger and reliability will be an issue and some overheating problems could become an issue.

But take that as you will, it's your motor.

You will like the 400, big block like low end torque with sb revving.

[/ QUOTE ]

If you can run yours at .030" with air conditioning and an automatic tranny pouring heat into the radiator, I'd be willing to bet that one without AC and with a manual will certainly last at .040".
 
[ QUOTE ]
[ QUOTE ]
[ QUOTE ]

It's a small block 400, bored .040 over,

[/ QUOTE ]
That bothers me, those walls are getting very thin. I have been told by a LOT of people that .030" is max for a street 400 because anything larger and reliability will be an issue and some overheating problems could become an issue.

But take that as you will, it's your motor.

You will like the 400, big block like low end torque with sb revving.

[/ QUOTE ]

If you can run yours at .030" with air conditioning and an automatic tranny pouring heat into the radiator, I'd be willing to bet that one without AC and with a manual will certainly last at .040".

[/ QUOTE ]
Maybe but I would be more worried about the reliability factor, those walls are getting thin and could crack at the bottom of the cylinder. I am just saying that I have always been told that .030" was basically max for a daily, reliable 400. Just what I've always been told and thought, if he was told different than fine, hope it lasts a long time without issues. I don't intend for this to turn into a pissing match. /forums/images/graemlins/screwy.gif
 
No pissing match, but mine was at .040 over and ne issues....

You should be careful at that bore.... /forums/images/graemlins/waytogo.gif
 
Yeah, I've pretty much heard the same thing. Based on what I've heard from others in the past that I know, going .040 over on a SB400 is like going .060 over on a 350.

.040 over is the max most shops will take a 400 here.

I have yet to encounter heating problems. I am expecting them. It had about an hours worth of running time on that bottom end with stock heads and an RV cam and a 3-core radiator, and with a bad carb and timing off, the idiots (they're friends, but they are morons when it comes to mechanical stuff) couldn't get it to run right and it overheated.

I'm glad I got the motor when I did before serious damage was done. All the gaskets were leaking, straight water in the block, timing off, bad carburetor...

and to top it off when I took it apart I found the JB welded oil pan was nearly solid rust in the bottom, and the oil pump pickup tube/screen was some used one beat into place out of a blown up motor and still had gunk in the screen.

Tonight I went and got a diesel radiator from a friend, and I'm hoping the extra capacity of coolant it will hold will help out, plus the motor has an external oil cooler, and I took out the AC condenser from the core support. I want to make sure I get maximum airflow, maximum coolant capacity and any other ways to help keep components of the motor cool. I should probably take out the heat blanket from under the hood, and make sure I install the fan shroud tomorrow.
 
[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
[ QUOTE ]

It's a small block 400, bored .040 over,

[/ QUOTE ]
That bothers me, those walls are getting very thin. I have been told by a LOT of people that .030" is max for a street 400 because anything larger and reliability will be an issue and some overheating problems could become an issue.

But take that as you will, it's your motor.

You will like the 400, big block like low end torque with sb revving.

[/ QUOTE ]

If you can run yours at .030" with air conditioning and an automatic tranny pouring heat into the radiator, I'd be willing to bet that one without AC and with a manual will certainly last at .040".

[/ QUOTE ]
Maybe but I would be more worried about the reliability factor, those walls are getting thin and could crack at the bottom of the cylinder. I am just saying that I have always been told that .030" was basically max for a daily, reliable 400. Just what I've always been told and thought, if he was told different than fine, hope it lasts a long time without issues. I don't intend for this to turn into a pissing match.

[/ QUOTE ]

While true that bored engines tend to run hotter, I wasn't intending on starting a pissing match either.

The whole point is that the cooling requirements for a rig with 1/2 a fan shroud, A/C, and an automatic vs. a manual trans rig with a fan shroud and no A/C or automatic are drasictially different.

You wouldn't believe how much difference it makes to remove that 200* fluid flowing into your radiator along with that condenser that just POURs heat into your radiator as you drive.

As to the walls cracking due to being thin, I doubt it. The cylidner walls are much thicker than you think. Having heat problems, maybe.....but cracking due to being too thin......no.

Didn't intend for this to be a pissing contest at all, but there are a lot of issues that pertain to why you have had cooling issues, and I doubt that mountainexplorer will have those problems.
 
[ QUOTE ]
The whole point is that the cooling requirements for a rig with 1/2 a fan shroud , A/C, and an automatic vs. a manual trans rig with a fan shroud and no A/C or automatic are drasictially different.



[/ QUOTE ]Correction, I have dual flex a lite 13.5" fans now. /forums/images/graemlins/histerical.gif /forums/images/graemlins/peace.gif
 
Finally pulled it out of the Blazer today and tore it down.

Found the following in chronological order:
1) Pieces of piston and rings in the intake runners (right under the carb)
2) Tip of #8 spark plug blasted off
3) 3 pushrods missing
4) Back end of cam sticking out rear of block
5) 3 lifters missing as well
6) Valve (#8 exhaust) broke
7) Oil Pan contents: Rings, parts of piston, lifters and bent pushrods.
8) Large section of #8 cylinder wall broken out
9) #8 rod twisted
10) Only salvagable parts that don't need replaced or repaired: Roller rockers; gear drive; intake; valve covers.

Many pics to come soon...
 
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