21HP V-Twin Head Gasket Repair

[Alan46]

You guys should get a room!

 

[Craftsman Garage]

Wdym?

 

[Alan46]

Just my sense of humor, don’t be offended!

 

[oldlawnguy]

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.

Search this forum for the thread:

B&S Valve Adjustment Hiccup (Murphy's law & not a pro)​

I replaced both head gaskets on a 24HP B&S V-Twin and the gang helped me through it with specs, tips and pointers. You probably want to get gaskets for muffler assembly, carb assembly as well. Torque the head in the suggested pattern.

 

[Hammermechanicman]

If it popping back through the carb after long storage probably was stored with the intake valve open and it rusted some so it is stuck open. Easy fix. Take the valve cover off and check.

 

[rhkraft]

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.

Probably over torqued if you broke them. On these little engines you set the torque in your elbow. Usually around 225 inch Lbs. Divide that by 12 to get ft lbs or 18.75 ft lbs. That becomes 18.75 lbs on a 12 inch lever. That is not much! estimate by picking up 2 1/2 gallons of water in a bucket ( Water is 8 lbs/gal). That's how pull you have to put on a 12 inch wrench handle. Use a criss/cross pattern a little at a time. On truck lug nuts that require 150 ft/lbs, use the lug nut wrench and step on the handle. If you weigh 150 lbs your on. If you weigh 200, add about 3/4 th of you weight.. Now, when you are done try to turn it a little more with you cross wrench. If you make it turn a little feel the force with your arms. You'll figure it out.

 

[Craftsman Garage]

@Alan46 did you mean a chat room?

 

[Alan46]

@Alan46 did you mean a chat room?

Yes!

 

[TobyU]

I always clean up the heads and they block service very well with a scraper and some Scotch Brite pad sometimes and then I always tighten in the Briggs recommended tightening order in two or three steps and I always use an accurate inch pound torque wrench and tighten to the current Briggs & Stratton recommended torque.

I will say that sometimes you have to be a little careful when you get right near the end of that torque because sometimes one will feel like it's not quite going to make it unless it strips or snaps off so if the torque you're going for is 220 inch pounds let's say, you might have to back it off to 215 or 218 or something and then see if it'll click and maybe not push it all the way to 220.
I think I broke one off one time and that's made me a little leery after that but I've done a whole lot more after that and never had a problem but I do get very cautious near the final torque.

This is not something you should be guessing at and just using a 3/8 drive ratchet to tighten.
Sure, people have been doing it for years can just use a criss cross method and get them to what they know is tight enough but ideally it's better to use a torque wrench.

 

[Gym123]

Probably over torqued if you broke them. On these little engines you set the torque in your elbow. Usually around 225 inch Lbs. Divide that by 12 to get ft lbs or 18.75 ft lbs. That becomes 18.75 lbs on a 12 inch lever. That is not much! estimate by picking up 2 1/2 gallons of water in a bucket ( Water is 8 lbs/gal). That's how pull you have to put on a 12 inch wrench handle. Use a criss/cross pattern a little at a time. On truck lug nuts that require 150 ft/lbs, use the lug nut wrench and step on the handle. If you weigh 150 lbs your on. If you weigh 200, add about 3/4 th of you weight.. Now, when you are done try to turn it a little more with you cross wrench. If you make it turn a little feel the force with your arms. You'll figure it out.

Head bolts are often brittle after they become 'work hardened'- he's not inexperienced in general, just with these engines, which don't require much torque.