HeliCoil? Headbolt hole

pulltilbroke

pulltilbroke

Last trailer park hero
Joined
Jul 15, 2008
Messages
319
Well I decided to tackle the headgasket this weekend, I was planning on having it done in a few hours but that didn't happen. The tear down went pretty quick but just as i was getting ready to cleanup the block I got a phone call from one of my good pulling friends, he was on his way home from a pull down in Kansas and his tow rig decided to spit the carrier bearing and driveshaft out on the hiway about 50 miles south of me, so I steal the old mans truck to drag his puller home and stillsmokin took his 86 Chevy K30 Crewcab down to haul his posse back, well anyway I didn't get home til about 12:30am so I decided to call it a night. I got up today and started working on cleaning up the deck surface and whatnot, well I get the head set on and am torquing it and on my last tq sequence I ripped the threads out of 1 bolt hole in the block. It is the hole between the #4 and #5 valve covers.

So my question is is there anyway to drill/tap and Helicoil it with out pulling the head and wasting the new gasket or will the gasket still be usable if I am careful pulling the head back off?

BTW I was on the 120 ft/lb tq sequence and I am using a 3283339 gasket I am also using stock bolts

sorry for the long post
 
Sorry to hear about this for ya man! That Sux!

I don't have the answer for ya but here's a free bump for those waking up that may be able to help ya...
 
i have ran heli-coil repairs in BBC/SBC

i used soem permatex black adhevis to seal the threads up.

and no there is not.. have to pull the head. you drill the hole out then re tap it for the coil to bring it back down to correct size
 
Yeah what he said! And the head gasket should be fine you didn't run it and it should come off clean. However if it does delaminate alot your gonna have to replace it.
 
Thanks for the advice guys.

I am now finding out that an M12 x 1.75 helicoil kit is a bish to find on a holiday weekend.

I'm keeping my fingers crossed that the gasket wont delam but knowing my luck it will.

Should I leave the head on till I have the correct size bit and use it as a guide to drill the block?
 
pulltilbroke said:
Thanks for the advice guys.

I am now finding out that an M12 x 1.75 helicoil kit is a bish to find on a holiday weekend.

I'm keeping my fingers crossed that the gasket wont delam but knowing my luck it will.

Should I leave the head on till I have the correct size bit and use it as a guide to drill the block?
Click to expand...

the drill bit will be biger htne the whole in the head
 
OK thanks.

I did however find a Helicoil kit though!!!!

Being this gasket has been torqued should I torque it a bit tighter after I get the block fixed? Say bump it up to 125 FT/LBs ?

Do you guys think I should worry about pulling thread out of other hole when it goes back together? This block has been torqued around 10 times to 130 ft/lbs, or could this have been just a flaw in the casting or somthing?
 
15w40 on the bolts, just few drops on the threads and a couple under the head.


What are you opinions on using copper coat on the gasket? I got the gasket off and it didn't delaminate and it looks usable so......
 
Use high-pressure lube such as ARP's... ~85% of torque is used to overcome thread friction (engine oil + multiple torques = thread failure).
 
Copper spray can crutch a coarse RA finish to help the MLS seal fluid.

Re-using an MLS in good shape on an undamaged deck & head works fine if you don't plan to generate extreme cylinder pressure.
 
What else do you reccomend, it is a Holiday and not a lot of places are open localy
 
Were not using an MLS gasket.

This is what were using
hg1.jpg

hg2.jpg
 
That's a .020" over 12V "marine" gasket - no need to spray that if it's new... if re-using, I still wouldn't spray unless sealing surface finish was compromised and/or gasket composition was damaged.

p.s. why are you decompressing?
 
A thicker headgasket decompresses such a minimal amount that it wouldn't effect anything
 
i would get one stud u will most likely pull the threads on the heil coil.
 
Well its torqued to 125 ft/lbs, and darn near ready to fire, just gotta bolt the turbo on, put on the heater lines and bleed the system.


Everything I've read and been told says that the helicoil will be stronger than the original threads
 
Yeah I've seen those before, but ther probly not available localy on a holiday.
 
You must log in or register to reply here.
Top