thermostat housing stud repair

[izzy1554]

while working on FWC install, i've been prepping the for the conversion installing a temporary T on the sea strainer so i could an acid flush, and do a pressure flush also.
while removing the the thermostat i realized why it took so long for the engine to warm up... no t-stat. while removing the housing i noticed 2 different bolts(1 stud, 1 bolt) and when i tried tightening down the bolt and stud, they both would not stop..
so, i bought the stud repair kit and was wondering if i need to drill deep enough into the block. i thought i read not to drill into the block but it seems like the stud and bolt already went in that deep...

i cant sail w/out the engine

[hanleyclifford]

The two thermostat housing studs are in fact head studs and they must be torqued at 35 ft lbs just like the others. Because of their length and dual purpose they are a frequent source of trouble.

[Tar34]

Nice heads up about the head bolts!

[izzy1554]

so....

i do drill and tap the block, yes?

[hanleyclifford]

Yes, If both holes are stripped you will need two repair studs. Don't use a bolt in this application. Work cautiously here since you only get one shot. Have you done this type of repair before?

[izzy1554]

yes i've drilled and tapped before but never on an engine block... the instructions says to have the stopper at 1-13/16" so that's when i started wondering if it needs to get drilled into the block because i thought it said not to...

should i drain the water? i am planning on not removing the head... hope all goes well tomorrow...

thanks

[izzy1554]

does this depth look correct?

[hanleyclifford]

I have never used a Moyer Marine kit for this so I am not sure about the instructions. But if you intend to tap the block for 7/16" - 14 (national coarse), the correct tap drill is size "U", which is between 5/16" and 27/64". The 7/16" bit is for reaming the head to accept the stud. It would seem you are expected to cut the new threads in the block without drilling with the "U" under the assumption that the stripping of the 3/8" - 16 original hole has already opened it up enough for the tap. So the answer is NO; do not go into the block with that 7/16" bit.

[izzy1554]

if the stud repair didnt work for the t stat housing, what would happens besides the leak?