Head bolts, are they really stretch bolts?

[Rob Scott]

allreet,

Are toyota E series head bolts, stretch bolts?

I cant find any data that says they actually are.

I know you tighten them 'like' stretch bolts with 90 degree setting, but it doesnt mean they actually are.

Cheers

[mikey4410]

ask russ78 lol

[russ78]

im of the opinion that basically the 90 degree turn is so inaccurate its not worth doing

your better off with 3 stages of torque 20-40-60nm that way you have the luxury of being able to accuratly check the torque of your headbolts after a period of time which is totally impossible with the very vague 90 degree turn

just my 2p on the subject im sure this will open a can of worms for many members but this information is from personal experience with stock bolts and arp's

but as for stretch bolts that I cant answer as ive only heard thats what they are

[Taggy]

arp bolts state to goto 60nm, the 90 degree thing is a bit wank

[H_D]

stock bolts are made to stretch. They are technically called TTY (Torque To Yield) bolts. Many manufacturers put TTY bolts in a head when manufacturing the car because they are the cheapest bolts available, and when you are using millions of bolts in a year even 0.10p a bolt adds up.Once these bolts are installed the first time, they stretch because they are made to. Once they are in your car for years they become rather worn out.When you take them out of your head they are stretched and should be thrown away (same with flywheel bolts). Never re-use the original bolts in your head. If you do you'll be buying another head gasket in a matter of weeks.

[russ78]

stock bolts are made to stretch. They are technically called TTY (Torque To Yield) bolts. Many manufacturers put TTY bolts in a head when manufacturing the car because they are the cheapest bolts available, and when you are using millions of bolts in a year even 0.10p a bolt adds up.Once these bolts are installed the first time, they stretch because they are made to. Once they are in your car for years they become rather worn out.When you take them out of your head they are stretched and should be thrown away (same with flywheel bolts). Never re-use the original bolts in your head. If you do you'll be buying another head gasket in a matter of weeks.

just wanted to add I saw for myself on the main database that it clearly states on 4e engines you can reuse toyota headbolts although personally I would never do this but just goes to show most of whats written is crap imo

[H_D]

just wanted to add I saw for myself on the main database that it clearly states on 4e engines you can reuse toyota headbolts although personally I would never do this but just goes to show most of whats written is crap imo

I wouldnt even re-use any type of headbolt so I went for studs instead and also using ARP studs on my main caps and flywheel.

[AdamB]

Studs are all well and good but are the most expensive. However they do last.

Whether the headbolts can be re-used or not, they should always be measured for stretch and compared with manufacturers tolerences, if they are out of tolerence, then replace them

[gorganl2000]

sometimes it really depends, new oem bolts may not be available, so the old ones are reused

my preference is news bolts, but having reused old ones, i've never had any problems in the past

also, we did some testing a long time ago...seems the final average is between 45 - 50 lb/ft when you install the oem head bolts as stated in the usual manner

i'm not a fan of the 90 degree final turn as its a bit "iffy", that's why we found an average to work with