CC 1320 engine mount bolts lost out

Three of the four have fallen out. Before I tackle taking the deck off, hoisting up the front end, anyone happen to know what size, type bolts I need to have on hand.

fine thread?
length?
dare I use Loctite?

How do I keep "em tight?
This happened one time befor????
Thx in advance.
Vertical shaft engine 12hp

had one mower I had to use lock nuts on as it would shake a regular bolt loose

You can use locktite and lock washers. If the bolt heads have holes for safety wire I would use that. Call the engine company with the engine model, type and code numbers. Hal

The best way to find out bolt size/pitch is remove existing bolt & measure dia/pitch & length or if eng mounting pads not threaded & just a clearance hole see what size bolts will fit in hole(standard sae nc/nf thread & 3/8"-7'16" diam)if mounting pads threaded then you have to check existing bolt as to weather sae or metric,some mfg have gone to metric.

As far as locking nut/bolt after finding out length of bolt,diam & thread pitch use a nut & lockwasher that match bolt & use BLUE loctite or use an elastic locking nut & lockwasher in place of loctite,if you've lost bolts before this would indicate a hi level of vibration on mower possibly caused by bent blade spindles,out of balance blades,bad spindle bearings or some other mech problem on mower,try to locate source of vibration if possible.

Thank you for you valuable information. I worked on the tractor this evening. I happen to find the head of a broken off bolt laying on the mower deck. 5/16 fine thread. I hoisted the mower up chain hoist) got under it and saw that two of the bolts have broken off... ends still up in the engine housing. These would be stub bolts. I managed to get another bold into the remaining hole.... have two bolts in now. The bolt that broke off according to the markings for machine bolts, this is a no. 5 hard bolt!!!!!
How do I get the broken stubs out? Screw extractors? I hav them... but drilling from under the mower, on my back now, and then trying to do that. Yuk. any ideas ???
True , there must be some vibration here, although I don"t really notice much. but must be if it broke two hard bolts. !!!!

Pull the engine. Sorry, but trying to drill out a semi hard bolt from underneath...not going to end well. You need to accurately center punch the stub and drill with a sharp bit. EZ Outs might work, or not. If not it might be best to find a machine shop to get then out with EDM or something. The engine costs a lot more than the bill for getting them out.

I'd be looking to find out why they broke in the first place.

Sorry. but educate me here. What is EDM?>

I agree with bret about pulling eng,in addition I would NOT use loctite on bolts as from what you say it appears bolts go into tapped/blind holes in oil pan,if you use loctite on bolts & they break again you're going to have a heck of a job removing them from block,a better way is use a flat washer & lockwasher under bolt head.

Pulling eng may also work to your advantage as to possibe cause of bolts breaking as I can think of 3 possible reasons in addition to possible vibration from mower deck.

1-orig/replacement bolts were a little too long & needed a flat washer or two on each bolt & bolt was bottoming out in hole before bolt fully tight against chassis.

2-oil pan casting slightly warped & requires shimming at each mounting bolt.

3-warped chassis,at the factory chassis pan is probably stamped out of one piece of sheetmetal,this can be done in a press with a one shot die,progressive die,automated stamping machine or done in 2-4 operations in seperate presses/dies,I don't know how mtd does it.Looking at assembly drawing/parts list for tractor there appears to be a large clearance hole in chassis pan so eng can be installed/removed with drive pulley installed on eng,if setup man/press operator was a little sloppy in setting up die in press or punches in die were dull/needed replacement when the die opened after punching pan the metal may pull slightly as die opens & punches retract into die,this can cause pan to dome,cup or twist slightly,you might want to use a straight edge & go diagionally across pulley clearance hole & eng mounting bolt holes & check flatness of chassis pan,you might have to use shim stock/washers to level eng on chassis pan.

Current problem: I found that two of the bolts were broken off. I managed to use screw/bolt extractors(EZ Out) to get one of the bolt ends out. Problem with the other--I broke the EZ out off IN the bolt!!!!! what do I do now? can I drill that? hard steel--bet drill bit wont work.
Don"t really know what to do.
One of the other holes. the threads are bad. Am trying to retap new threads. Need to get the right size drill bit for a 5/16 tap NF Takes a 17/64 bit. Have to find one..
Also, you think these four hole in the bottom of the engine, do they open up into the crankcase or just dead end in the casting. Cant really tell...

Yes, the original bolts had flat and lock washers under the head.
You shed some new light on this. Seee my new post at the top...I broke an EZS out....

My local CC dealer (CASE-IH) said to hoist up the front of the tractor...practically sitting it on end...they do in the shop...so that I can comfortably get to it... that works well.
Can see, drill, .....

I meant to add..the CC mechanic said that there is something strange going on here in terms of vibration. said to run it without the mower deck on and see if notice anything. Deck is already off...

Thanks all you guys for your thoughts and input .........

I couldn't see where anybody filled you in. EDM stands for Electron Discharge Machining, kinda like plasma cutting but more precise. It will remove hardened steel EZ-Out pieces (or broken taps) and sometimes not foul the threaded holes.
Bryce

You are NOT going to drill an EZout. Too hard. You CAN try to BREAK it out using a punch. Usually, you can at least loosen it up to the point that you can get it out with a magnet.

For the hole with the bad threads, I suggest a heli-coil or similar thread repair. Makes a good long term repair.

In every case that I have seen, engine mounting bolts do NOT go into the crankcase. Consider...a broken or loose bolt would become a MAJOR oil leak in an instant. That would be some pretty lousy engineering IMHO.

You're probably better off taking eng to a machine shop,as you stated previously existing bolts are 5/16" so if existing threads stripped finding a right size drill bit/tap for 5/16" won't help you as there's probably not enough meat on id of hole to hold a thread,if you take eng to a machine shop they can probably install a heli coil or increase bolt hole/threads for a 3/8" bolt in addition to possibly getting broken bolt/extractor out,if they increase bolt size to 3/8",you'll probably have to open hole in chassis slightly for bolt.

As far as bolts extending into oil pan,if they did oil would run out of pan when a bolt removed,if a tapped blind hole when bolt(s)removed there is no oil loss,easy way to find out is take a thin blade screw drive,awl,ice pick or thin wire & stick into bolt hole & see how far it goes into hole before it stops.

Sorry. I should have told you what an EDM is. Someone else covered that. Take the engine off and to a machine shop before it gets worse. I would recommend doing as Joe said and having the holes opened up and retapped to 3/8 fine thread.