AgRunner06

Sorry, but after seeing that poor craftsmanship, there's no way in hell I would buy those. Why don't you just buy some OEM studs because you probably won't have the engine apart again? Otherwise I'd have some made.

Good luck guys

FireMan

well, there aren't any oem studs. only bolts. I understand getting the bolts now to sell the engine later, its the principal of the matter that make me say :wtf: .

It's interesting to see that the studss are not all even length. I would be interested into seeing the head/valve problem you have going on.

I beliebe OEM bolts are around $200? Is there any one in SoCal goes to that has good 3.4 engines that don't need a core deposit?

Ganoid

I just bought into the heade bolt causing gasket failure hype. I may just sell the studs I have now to unload them and just get OE bolts or equivelant.

http://www.engnbldr.com/
these guys sell OE replacement TTY bolts for about 37$ if i remember correctly. Thay usually sell sets on Ebay but you can just call them directly. Very nice to deal with and thay are local for me.

MTL_4runner

It is ok that the studs are not even length, just tells me they are made by hand.
The problem with those studs is where the threads meet the body of the stud.....notice where yours broke!

FireMan

Mine broke 3-4 threads into the threaded area. Some of the trhreaded areas seem longer than others.

FireMan

Heheheheheh,

I was showing my old man my plight, and he said the studs looked stretched. I re-examined the studs, and on 2 of them for sure, the threaded area in the block is now narrowed. I took some more pictures, but my camera can focus on something super close up. Check it out. These were the worst and most obvious candidates. I just ordered replacement OEM bolts today. I am going to take out the other studs and replace them. I wonder what they will look like. I also will need to get another gasket now.......

heres the webshots link. go to DOA link

http://community.webshots.com/user/darkronin619

MTL_4runner

You said you torqued them to 60 ft*lbs each right?
What torque wrench did you use? Can you verify with another one?
It is easy to do, just tighen with the second one then try yours....it should click without turning.
If it does turn then your wrench needs to be calibrated.

Either there is alot of force being applied or the studs were made of inferior material.
I should hope he used chromoly steel or something similar.
Any way you can ask DOA what the material is too?

Then we could do a simple calculation:

T = K x U x D x P

K is a constant that equals 1.33

U is the coefficient of friction (usually 0.2 unlubed, while 0.09 is conservative)

D is the basic diameter of the fastener (at the smallest part in inches)

P is the preload force on the bolt (lbs of force)

T is the torque on the bolt (convert to inch-lbs)

so now (60ft-lbs * 12) = 1.33 * 0.09 * D * P

I need the diameter at the threads and we can solve for the force.....that will tell us if the material was junk or if the force is quite high and requires a high strength alloy like 190ksi chromoly.

if I use 0.375 as the diameter I get about 16,000 lbs or about 145ksi stress.
That is pretty high so I would guess they do need to use good quality material or you would yield.

ahhhh....this brings back memeories!

Firefyter-Emt

I still don't get it. I have re-used my bolts 3 times now and have never had a gasket leak.. I still say it is a combo of the poor gaskets, block design and the very very poor flow ot the crossover pipe into the left bank manifold.

Good luck! BTW, I would assume final tourqe to be in the 150 range.. that second 90 degree crank is pretty dang hard to do!

Ganoid

I think the problem is 2 fold on the head studs.
1) the threads are cut from the inside out. There is a complete cut all the way around the stud where the threads start. I assume this is where thay set thier cut depth then hit the auto feed on the lathe. Thay should have started cutting from the outside in. Instead of just stopping the drive carriage thay should have just backed it out really quick as thay where passing the end of thier thread run.

2) I think the material is substandard. If you look close at the pics you can see thay where cut to length with a hack saw. A quick and dirty test I did personally was to grab an old used sawzall blade off the top of my tool box and see if i could score the end of the stud by hand using the old blade. The material seems fairly soft and not at all what I would expect. I know thats not any sort of valid test but I was hoping it would be hard enough that scoring it by hand with an old sawzall blade would be difficult.


Any one want to buy a set of DOA head studs? I got a deal on them and I'll sell them for what I paid for them I just recently took them out of the package thay have never been installed.

FireMan

Awwww, thats not fair. Does anyone want 15.75 studs?
Anyone?

934rnr

My heads are back on using some new head bolts. The trick is use a really short 1/2" extendsion and a 1/2" 12MM 12pt socket to reduce flex when torquing the head bolts with a 1/2" torque wrench.
DO NOT use a 3/8"dr socket or extendsion they flex too much to get a good torque yeild out of them.

The other trick for the final 2 90 deg 1/4 turn torque sequences is to use a 1/2" breaker bar that doesn't have alot of flex at the swivel pin and before you start torquing it pull the breaker bar slightly so it won't have and side play then get a good pull out of it continue to have pressure on it during the whole turn do not let off. do the same thing for the final torque pattern.

mt_goat

[QUOTE=Firefyter-Emt]I still don't get it. I have re-used my bolts 3 times now and have never had a gasket leak.. [QUOTE]

Why do you keep pulling your heads off if you don't have a leak? Are you replacing the HG each time?

FireMan

Sorry I don't have any measurements, been kinda busy. I just got my heads installed using new OEM bolts yesterday. The engine is finally starting to look like an engine. I did manage to completely kick (on accident) my organized bolts and nuts tray, so I am spending today trying to match up bolts to holes. What fun.

Still have not heard back from DOA yet. ......

mt_goat

I see what you are talking about with the stretched studs, it is very evident when you look at the threads. Were the pictures taken before or after you torqued them?

MTL_4runner

How much were the ARP studs and what size are they?

FireMan

The studs stretched after torquing them down, then removing them. As for installing them, they were nice and snug.

I just got a voice mail from Tim yesterday. My engine is back together now, so we will have to work something out.

Praufet

Did anyone find out info on getting someone else to make the studs? I am going to be replacing my 3.slow and would like to try and replace the head bolts to improve the reliability. Don't want it breaking down on me again.

Babypig

If you end up keeping the studs, i wonder if you'd send one up and i could do some hardness tests on them. I'm in the middle of taking a course in Non Destructive Testing and am doing an analysis of the V6 OEM head bolts. So far i have done rockwell hardness tests, Charpy notch tests and tensile strength or strech testing. Don't have the numbers here or I'd give em to you. My materielas engineering instructor can't figure out why Toyota would make a stretch to yield head bolt as when torqued to spec the head bolt is past the modulus of elasticity and into the plastic deformation stage. He was saying that by reducing the torque spec by 5lbs/inch they would react better and not stretch. He thinks that is part of the problem that Toyota has been having with the head gaskets. Let me know either way and good luck with the rebuild.

Steve

Bumpin' Yota

My brain just turned into goo.... huh?

Can you explain all that to a simple microbiologist like me? LOL

mt_goat

How do you know the Toyota head bolts (OEM) are being torqued passed their yield strength?