While doing the second torque sequence on the heads the threads pulled out of the block on 3 of the bolt holes. Are there any options to repair this or is my newly machined 4 bolt main block now a boat anchor.

 

You should be able to repair this with a Helicoil. Most good hardware stores carry a variety of sizes.

http://www.roadstarmagazine.com/modu...rticle&sid=233

GUSTO

 

Find out why they stripped before repairing them, did you chase the holes with a chaser or a tap? If it's a tap I would advise to check all threads and if necessary install heli coils in all threads that are not 100% intact.

 

Use the Heli-coils to fix it. I had that happen to me when my cliker type torque wrench did not "click".

Set it a little lower next time.

-Mark.

 

I had torqued the other head with no problems. Three sequences at 40, 55, 65. I had considered using a helicoil but have never heard of it being done on head bolts before.

 

Did you chamfer the holes when you chased them?
Gary

 

 

I've helicoiled motorcycle head bolts (12.5:1 compression -- not the lightweight stuff) as well as spark plug holes. Never, not once, had a helicoil fail.

And dittos on figuring out why they stripped out. I've never heard of anyone helicoiling after a helicoil failed. Mostly because I've never heard of a helicoil failing.

 

This is really odd. Figure out why and check the rest, as this should not have happened.

Hans

 

Yeah - almost sounds like the bolts are too short or shoulders on the bolts too long.

 

Can someone post a pic of a heli-coil? I have a tranny pan bolt that could use some help....

 

Here is a solution I have used on my Harley.

They are not prone to breakage like a helicoil is.

http://www.timesert.com/index.html

Chris B

 

If there is a concern with using a heli coil, then use a timesert.
www.timesert.com

A heli coil will not hold a head bolt reliably in an aluminium block, only a timesert will last forever.
A heli coil in a steel block should be fine.

Barry

 

Those have a flange... you would have to either machine the block to receive the flange, or machine the flange off after installation.

Helicoils should work.

If you use a "clicker" type torque wrench, my bet is it's out of calibration or broken or cheap or all of the above.

I don't trust them for engine assembly. I use a beam type and steady hand.

It's also possible that somebody else weakened the threads before you.

 

Nothing wrong with a clicker if you just don buy cheap junk and turn it all the way back to 0 after usage, store in it's container and it will last a lifetime. I check the calibration on mine from time to time (w/ a beam type) and it's dead accurate all the time.

 

when you install the helicoil, use some sort of sealant. you dont want antifreeze seeping between the helicoil and block.

 

The installation kit for these has a countersink so they set flush.
Chris B

 

That is really, really weird.

I just retourqued my POS albatross engine, using the ARP L19 studs, and that called for 105. I made it 110. I thought standard SBC head bolts were 95. I've had head bolts break but never a hole dethread. I've never done them on an aluminum block so I assumed that was more likely there.

How much effort did it take to do that 65? That 110 was almost undoable without a cheater pipe as I had to do it one handed to secure the stack of extensions (which really added about another 5 pounds.) 75 pounds is typically a good effort one handed pulling from the end of a typical length torque wrench.

I put silite on all of the head bolts to make sure I have seal against water on any of them - whichever go into water jackets (and thus have uniform torqueing. I've always wondered how that works with retorqueing months later, after the silicone has dried. I know a non hardening putty product exists, but I've never used it.

-------

Oh - on the clicker vs. beam. Beam ones can be altered too. They may be inherently more accurate, but a danger exists of overtorqueing without knowing it. I use a clicker especially on in-car stuff because I cannot reliably depend on seeing the beam bend at the main effort of the pull in many locations and angles and may overtorque. On one of my head bolts I retorqued - and some of those required over a three quarter turn! - I did not hear a click but decided the effort was close enough and the wrench may be faulty so left it there. You always have to use some judgement and not be blinded by the instruments.

 

Good news, I desided to use the helicoils and arp studs I put the helicoils in with 262 non removable locktite and then used 242 removeable locktite on the studs. Installed the heads and and torqued in 3 sequences 40, 55, and 65. Everything went as it should I should sleep a lot better tonite. I'm not gonna touch the engine for 24 hours to let the locktite fully cure then I'll start back in on it. Many thanks for all the Help. The only thing is I'm wandering should I go ahead and stud the other head so they will both match.

 

I have a 30 year old beam type that has never been dropped and I don't let people borrow it. Still dead on.

RE: the angles... same holds true for a clicker.

I have both types. When you're installing heads, main caps or rod caps, it should not be difficult to maintain the correct angle anyways... if not, you're in the wrong business. IMOP

An expensive "professional" clicker works fine.

I matched my beam against a forum members mid priced clicker (while we were assembling his engine), and he had to disassemble & re-oil it after every 4th bolt. It kept going off calibration.

No such mystery or gray area with a beam type. Either it's on, or it's off cal.