well are the bolts torque to yeald . and the next questiion is do you want to do the whole job all over again? if not then get the correct new head bolts and make sure the block is clean no water or grease or dirt in holes. i sure as hell wont reuse no head bolts- When i was 8 to 12 years old i fitted the head on a 1962 opel kadett with the old headbolts fixed the gasket with rope lol. guess what 1 bolt broke when i torqued it.
tony9,
Jan 26, 4:30am
What does the service manual say?
Some need to be replaced every time. Some can be replaced after inspection. Some need to be tested for length.
Big variations between manufacturers and models.
Some torque to yield bolts/studs can be reused (Jeep for example), some not.
franc123,
Jan 26, 4:32am
I would be more concerned if the corrosion had bitten more into the threads, which is doesnt look like it has. What is the final bolt torque, 90-100Nm? Replace the two of them if you want to but I dont see it being a problem. A machine shop might have some some lying about.
franc123,
Jan 26, 4:41am
It's a bit hard for the untrained eye but there is generally a section of the upper part of the shank that is of a reduced diameter.
franc123,
Jan 26, 4:56am
It's not a stretch bolt.
kazbanz,
Jan 26, 5:18am
Is it worth the worry that they MIGHT fail ?-The very fact you are asking the question means its a concern to you. Throw in two more bolts from Toyota and rest in peace
marte,
Jan 26, 5:34am
We were taught at Polytec not to wire brush threads on bolts or studs that were intended for this situation, head bolts in particular, & fastenings used in 'life & death' situations. Something about scratching the root of the thread profile, weakening the metal & causing it to snap there. They said to use a die nut to clean the thread.
franc123,
Jan 26, 6:14am
Based purely on your photos, yes. It would be worth doing in your case to screw the bolts into the block the full depth of the thread with the head still off, and grip the hex with your hand and see if you can feel any movement in the threads, either side to side or up and down. Obviously the block thread should be clean and dry.
intrade,
Jan 26, 6:26am
based on facts get new ones if you cant well . good luck.
franc123,
Jan 26, 6:53am
You wouldnt know faeces from clay mate, you prove it over and over.
intrade,
Jan 26, 6:59am
18 i don't quite know what you base your superiority know-how on . but i would say you start learning material fatigue engineering and come back when you have got a clue not just slag other people off who make valid comments based on facts. the question Was Thoughts on reusing head bolts? thats my thougts . if the op wants to take it on bord or not is not my concern.
muppet_slayer,
Jan 26, 7:11am
Based on your photos I would reuse them. Look at it this way. On a good head bolt the thread itself is cut deeper in toward the center of the bolt than the pits are, and reduces the thickness of the bolt quite considerably yet you don't see them all breaking at the threads do you. They are very thick bolts for the job so I don't see a problem reusing them. TTY are usually much thinner than your head bolts.
intrade,
Jan 26, 7:12am
i did not think much of polytech usually . but to explain what happens if you use a Die your flanks are clean and correct angle as where a wire wheel only buffs the dirt off and any distortion is still present. if you get a lot of metal with a die you would not want to reuse any bolt. So yea the polytech is not extreem wrong. you would want to know the exact reason , metal fetigue is still present on bolts and cast iron and aluminiom have a different expansion rate its what the headgasket has to deal with . Studs are used with more extreems
franc123,
Jan 26, 7:14am
It's called years of experience. You don't know what a Y series Toyota engine is nor even know it does not use stretch bolts nor can even visually identify a stretch bolt when its put in front if you so that's yet another epic fail from you for all to see as a result of non existent training and assessment skills. That is what you are basing your automatic replacement theory on, nothing else.
franc123,
Jan 26, 7:18am
Ya some of these modern head bolts are like knitting needles by comparison.
muppet_slayer,
Jan 26, 7:18am
Torque to yield usually use an angle (1/4 (90deg) or 1/2 (180deg) of a turn at the final stages of the torque down. On some of the engines I have worked on you can actually feel the bolts stretch. 6cyl Ford Falcons come to mind.
muppet_slayer,
Jan 26, 7:21am
Yeh. I remember taking a gulp before each tighten because they feel like they're going to snap lol
intrade,
Jan 26, 7:24am
24 you remind me of my pome mate. said 1 bolt was to long grinded it off so he could torque it and now he removed the head again i did agree with him that compression is gone between 2 and 3 cilinder. i only said you done that hesdgasket in the last 2 years. I wonder if he goes and reuses the bad heatbolts all over again He sure would if he listens to experts like your self. tha fact that the bolt in immage is not torque to yeald has nothing to do with it not having fetigued .
cabrio1,
Jan 26, 7:51am
have you tried Toyota for a price? Sometimes quite reasonable. Otherwise about $100 au on eBay.
Or inspect them for necking as per the manual. If they don't meet the torque on installation replace the lot. Personally after all the effort that goes into an engine rebuild just spend the extra hundy for peace of mind.
jmma,
Jan 26, 8:06am
What a load of crap, it's a 3Y toyota engine, bolts will last another million Ks
cattleshed,
Jan 26, 8:09am
They will be absolutely fine! As said just make sure every surface including the threaded holes are spotless. You will need compressed air for that and brake cleaner would be good. Thoroughly cover bores, water jackets etc. first and reassemble using correct torque pattern and stages. Report back.
cattleshed,
Jan 26, 9:24am
Do you mean a) refitting the complete rocker assembly onto the head OR do you mean b) reassembling the shaft onto the rockers and springs? I presume you mean a). Step away. Have a cup of tea. Return and take another look. Did you dismantle the rocker assembly? Should be a case of lining up and seating push rods and attaching bolts / nuts.
cattleshed,
Jan 26, 9:29am
Sure, replace both manifolds and the sump and also ALL sump bolts. No scrap the lot! Get a brand new engine from flywheel to pulley as there is no sense in taking chances on any of it!
ronaldo8,
Jan 26, 9:40am
Ha exactly what I was thinking, but really, best be sure, dump the entire car, its sure to be suffering from metal fatigue, never can be too sure.
I'm suffering from mental fatigue just thinking about it.
ronaldo8,
Jan 26, 10:16am
Yes its normal. They are non inference so even if your cam angle/valve timing was completely out you'll be fine.
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