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curlett

Briggs engine head gasket

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curlett

I have a 7116 with the single cylinder Briggs engine in it. Over the past 2 years the head gasket had failed twice, that seems pretty odd. Both times I've replaced it I cleaned the block and head well and the sanded the head on a flat surface so I know it's not warped. I hear air hissing out so I'm going to have to replace it again. Is there any reason that it could be failing or maybe just a coincidence? I guess I'll know over more time if it keeps happening. Thanks for any help!

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huffy

Some sandpaper spray-glued to a piece of glass is a good way to make sure the head is flat. Just rub the head on it gently then look to see if and spots aren't scuffed; means they're high cause it's warped.

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chris87

If using a aftermarket head gasket I have had to retorque the head bolts before each time I ran it for the first five or so times. Never had to do that with a Briggs gasket. Also runs tap down each hole to clean the treads blow them out and put clean engine oil on the threads and washer to reduce friction it will give you a better and more true torque. On Diesel engines they has a special paste to put on the treads and washers but your talking 300 to 600 ft lbs of final torque. Oil works good for the lighter torque.

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BLT

One more item, make sure the threads you lube are the bolt threads only, not the block. If you oil the block threads, a pocket of oil might or will give you a false torque reading or strip threads as the oil won't compress.

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rokon2813

BOLT TORQUE FACTORS

LUBRICANT OR PLATING TORQUE CHANGES

Oil Reduce torque 15% to 25%

Dry Film (Teflon or moly based) Reduce torque 50%

Dry Wax (Cetyl alcohol) Reduce torque 50%

Chrome plating No change

Cadmium plating Reduce torque 25%

Zinc plating Reduce torque 15%

Baseline torque is calculated for a non-lubricated, un-plated boltid="red">

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dirtmister16

everyone has gone over most of what ive done/would say already but i will add this.

one thing i do when doing a headgasket is not only do i lap the head in and make sure its sqaure. i also do the tops of the where the washers sit if possible. some briggs heads you can do that to some you can't.

for the ones you normally can't what i do is take a steel rod and a length of emery paper and touch them up. just make sure the rod has a sqaure end and your holding sqaure.

also when cleaning the holes in the block, when done running tap in them clean them out really good. i use gas to clean out the oil then blow it out with compressed air. be sure to run the bolts in the holes afterwords and make sure they fit well.

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MrSteele

I had the first problem ever with a head gasket this year. This is also the first of the newer style gaskets I have had to use. The old gasket had perforated steel faces that could be used over and over until blown. The new gaskets require proper torque, at installation, after running a while, next year, the following year, or even more often depending on use of the engine, just to be certain.

There are no lock washers on these bolts, don't use them unless you want to damage your head. Exception to that is for brackets bolted on the head, use lock washers on the brackets that have a head bolt through them, such as the starter generator bracket. Added brackets are a problem in themselves. If you have brackets bolted with a head bolt, those bolts have a tendency to shake and loosen bolts.

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ss74nova

You can also use brakeclean to spray in the headbolt holes then blow it out with air & lightly oil the threads on the headbolts. When I worked for a Dodge dealership, Neon 2.0L headgaskets were always going bad untill 1999 when they changed from a fiber gasket to a 3 layer steel gasket. The way we checked for flatness on the aluminum head or steel block was to clean up the surface first, we used a die grinder with a nylon roloc disc so it wouldn't damage the surface (green for steel,yellow & white for aluminum, yellow took more off so you had to be careful, white took the lightest amount off) & use a straight edge that you could purchase from Snapon or Mac, which was just a flat piece of iron stock that was machined to a perfect edge. You would lay the straight edge on the head or block & try to slip a .002 feeler guage underneath it. If it was bad it had to go to the machine shop. You would lay the straight edge on the head or block in all different positions longways, shortways, & criscross across the head to see if the feeler guage would slip under the straight edge any where it made contact. All the headbolts I've seen on cars only had the round washers too.

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powerking_one

Quote:

"Try torqueing the bolts, then wait about 30 min and check the torque.

To get a true torque the bolts shouldn't have lube on them."

______________________________________________________________________

Actually, this is an untrue/inverse statement. A more true torque reading will always be attained if there is no binding on the threads or bolt head interface to the surface. Case in point being that with modern automotive torque-to-yield head bolts, the torquing instructions have you put sealant on the threads and/or a drop of oil on the bolt head surface to get an accurate torque spec. Most of these torque to yield bolts have you crank them down like 180 degrees to final after some initial torque wrench spec.

Tom (PK)

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Vinnie_A

I had the same problem with my 14 HP Briggs after pulling an overloaded trailer up a steep hill for the better part of a day.There was no power at all and It sat here for a year or so and I thought the engine was shot. A member suggested a new head gasket and to torque the head bolts. Simple fix for me.

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trowel

Was going to replace the gasket on mines but torqued the head bolts first and it stopped, saving the gasket for when i decoke the head.piston and re-lap the valves.

Always blows around the exhaust valve side of the head.

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AC82

While we're on this topic, what is the typical torque spec on a head for a single cylinder Briggs? I have yet to come up with anything more precise than 3/4 turn past snug or something like that. I think the last one I did was a 9HP 23D.

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