Briggs vanguard 18hp 350777 broken rod

junkman108 · Jul 25, 2018

Tinkerer200 said:
I don't think that crankshaft will clean up without turning under size.

"Also the condition of the camshaft bearing surfaces in the engine. I suspect that they are also damaged."

I suspect the camshaft bearing bosses are cracked.

Walt Conner

they used to make a .020" under size but it is obsolete. If the cranks is cut wouldn't the connecting rods have to be oversizex not undersized ?? Or do they just call it undersized because crank journal is undersized? These engine don't use rod bearings.

Tinkerer200 · Jul 25, 2018

First thing to do is check those camshaft bearing bosses. Don't see how a camshaft can be broken in two without damaging them. Considering the cost, I think your engine is junk. IF I understand you and undersize con rods are no longer available then your choices are a new crank or have the old one built up and turned back to std., both very expensive choices.

Walt Conner

junkman108 · Jul 25, 2018

i posted pictures camshaft boss is fine

bertsmobile1 · Jul 25, 2018

Thank you for the better photos.
Cam journal bush looks good but you really have to mike them

DixyKnocker · Jul 26, 2018

the kohlar on the dixy windowed the block and it broke just above the crank
\
motor was ill fated when we got the machine had been sitting was very tight and generally unhappy likely old starvation

from the pictures that looks like oil starvation and that crank is toast its heavily scored and galled

by the time you re polish and clean it up the clearances will be to loose

vanguards are cheap enough they put them in everything find a used tractor and pull the motor like we did

junkman108 · Jul 27, 2018

Well pull the crank and the flywheel side of case and it does have replaceable bearing insets but its in excellent condition no streaking or nothing..

I used acid on crank and the aluminum came off! The journal is smooth can catch my fingernail on anything it but has discoloration.(going in for tonsillectomy tomorrow so wont have time to try to polish) Briggs chart says the crank pin measurement is 1.455" . Does it have to be exactly 1.455"??? what is tolerance range. Before looking at specs i measured it with a cheap digital caliper and got 1.455-1.457. cant tell the bad journal from the "good one"

DixyKnocker · Jul 27, 2018

I don't know why you are hell bent on saving this vanguard
cost isn't the issue its gonna cost you more in the end to try and save this motor then simply surfing craigslist for a parts tractor or used motor

but since you are hell bent

take the crank to a machine shop and have them polish it seriously its worth the couple hours of labor cost to have it done right

you can do it on the bench but it takes a ton of time and you can ruin the crank if you don't know what you are doing

start with 400 emery cloth and work up to 1000 or 1500 make sure not to rock the cloth work in long wide slow strokes make sure you get a full 360 on every pass (make sure the cloth is wide enough todo the journal in a single pass

if its really just discoloring then all you need is some 1000 emery cloth and a eagle eye

bertsmobile1 · Jul 27, 2018

Discolourising is not the metal changing colour, it is the oxide coating changing colour & getting thicker.
Once it is removed you will be amazed just how thick it is.
You really need to measure the rod clearences with plasti gauge strips.
Operator variations in micrometers means the just don't cut it for fractions of a thou.

junkman108 · Jul 27, 2018

I dont know about your neck of the woods but here Vanguards are rare. Now Kohler Commands are a dime a dozen. I never rebuilt one before .ill be into no more than $200 maybe even with new rings.

AS for plastigauge. Where would i find or calculate clearance spec? I can only find crank pin specs.

Thanks

Tinkerer200 · Jul 28, 2018

junkman108 said:
I dont know about your neck of the woods but here Vanguards are rare. Now Kohler Commands are a dime a dozen. I never rebuilt one before .ill be into no more than $200 maybe even with new rings.

AS for plastigauge. Where would i find or calculate clearance spec? I can only find crank pin specs.

Thanks

Any Auto Supply Store and the gauge comes on the paper container strip.

Walt Conner

Briggs vanguard 18hp 350777 broken rod

More options

junkman108

Member

Tinkerer200

Well-Known Member

junkman108

Member

bertsmobile1

Lawn Royalty

DixyKnocker

Forum Newbie

junkman108

Member

DixyKnocker

Forum Newbie

bertsmobile1

Lawn Royalty

junkman108

Member

Tinkerer200

Well-Known Member

Footer Links 1

Footer Links 2