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21HP V-Twin Head Gasket Repair

#1

GasGuzler

GasGuzler

I just picked up a Craftsman LT1000 with a 21HP Briggs V-Twin, model number 407577-0283-E1. I believe it needs new head gaskets, I have ordered the gasket kits but I was just wondering if I need to order new head bolts too? In the past I have ran into issues reusing head bolts and them snapping in the block while torquing them down. I was also wondering what the torque specs are for the head bolts, and how many stages I should torque them down and how many foot pounds for each stage. I’m 18 and fairly new to this, so any help would be appreciated.


#2

Craftsman Garage

Craftsman Garage

So, I have reused head bolts many times and never had any lssues. I also didn't torque them down and didn't have issues lol. I would pull out a bolt or two and if they're really Rusty or corroded, etc, then replace them. Otherwise, I wouldn't replace them. BTW, Welcome to the forum!


#3

GasGuzler

GasGuzler

Craftsman Garage said:
So, I have reused head bolts many times and never had any lssues. I also didn't torque them down and didn't have issues lol. I would pull out a bolt or two and if they're really Rusty or corroded, etc, then replace them. Otherwise, I wouldn't replace them. BTW, Welcome to the forum!
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Oh alright, I’m used to rebuilding truck engines and torquing everything down in stages and in a pattern. Guess I will tighten them down what I think is enough and hope for the best.


#4

Craftsman Garage

Craftsman Garage

Would you happen to be GasGuzler on YouTube?


#5

GasGuzler

GasGuzler

Craftsman Garage said:
Would you happen to be GasGuzler on YouTube?
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Lol yeah that’s me


#6

Craftsman Garage

Craftsman Garage

GasGuzler said:
That's awesome dude. Let me start by saying I enjoy watching your videos. I bought my 72 F100 at 13 years old after watching your video about your 76 back in 2022. Last year, I wanted an OBS so bad after seeing lots of Videos come up about them. I got a 92 f150 std cab shortbed 4x4 manual last August. Its not an inline 6 tho, its a 5.0. With the help of this forum, I fixed some riding mowers and bought those trucks. Long story short, love the content so Keep doing what you're doing brother!
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#7

GasGuzler

GasGuzler

Hell yeah man! I honestly never expect anyone to recognize me let alone on a lawn mower forum haha, but that’s awesome that you’ve got some trucks of your own! A buddy of mine convinced me to buy a cheap LT1000 off of marketplace, and I don’t know how but somehow I’ve become addicted to them and now I currently have 4 sitting in my garage, it’s becoming an issue lol. So chances are this won’t be the last post I make on this site, that’s for sure. Plan on turning this 21HP twin into a race mower just for fun, might even make a video series on it. Not sure how the community will enjoy mower videos instead of truck videos but we’ll see.


#8

Craftsman Garage

Craftsman Garage

GasGuzler said:
I know exactly how that is lol. I've got a channel with truck content and riding mower content, I think the link is in the about section of my profile. I would watch lawn mower content on your channel. Btw, if you make a racing mower, don't use hydrostatic-automatic transmissions. Only manuals can go fast because automatics have rev limiters and they're really weak.
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#9

GasGuzler

GasGuzler

I figured as much, unfortunately my V-Twin is a factory Hydro-Static. I was planning on swapping the 6 speed out of my other mower into it, but how would I go about bypassing the rev limiter?


#10

Craftsman Garage

Craftsman Garage

Manuals Don't have rev limiters. Post your mower's model no. It should start with 917.Xxxxx


#11

GasGuzler

GasGuzler

Craftsman Garage said:
Manuals Don't have rev limiters. Post your mower's model no. It should start with 917.Xxxxx
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Currently away at school but I’ll have to check. And is the limiter actually part of the transmission or is it like a CDI box on the engine? Because if it’s just the tranny I can just swap it.


#12

Craftsman Garage

Craftsman Garage

No, the engine could go up to 7k if you wanted it to. It's an internal part of the transmission. It would probably be easier to swap in a manual.


#13

GasGuzler

GasGuzler

Craftsman Garage said:
No, the engine could go up to 7k if you wanted it to. It's an internal part of the transmission. It would probably be easier to swap in a manual.
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Sounds like I’m doing that then, I already wanted to swap the rear fender since it’s nicer so this just gives me more reason to lol.


#14

Craftsman Garage

Craftsman Garage

Also, there's nothing wrong with Briggs v-twins, but if I was making a racing Mower, I would prefer a Briggs opposed twin. Basically the "indestructible inline 6" of mowers


#15

GasGuzler

GasGuzler

Craftsman Garage said:
Also, there's nothing wrong with Briggs v-twins, but if I was making a racing Mower, I would prefer a Briggs opposed twin. Basically the "indestructible inline 6" of mowers
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Haha my teacher at school has a 20HP opposed twin, he told me I could have the motor in the spring if I swap another motor onto his. I just like the sound of the V-Twins.


#16

Craftsman Garage

Craftsman Garage

IKR, the vtwins with open exhaust sound like motorcycles. IMO any engine is better than a single cylinder for a racing mower. Vtwins are also wildly reliable most of the time.


#17

I

ILENGINE

Head bolt torque is 220 in/lb. I usually do a three step process.


#18

StarTech

StarTech

You could cripple the governor and rev the engine up until a rod goes thru the cylinder block. Note these Briggs are design to run safely at 3600 rpms max.


#19

Craftsman Garage

Craftsman Garage

Hey, that would make some good content... "Driving my racing mower until it throws a rod" Iol 😉


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