OK now that i'm putting it back together FINALLY...

[Figit090]

Too late now it sounds, but you just measure the clearance and then lap the bearing caps to remove enough material to get back in spec. The valves push the cam upwards so the majority of the wear is in the cap. Loose bearings makes the valetrain noisy, reduces oiling at the back bearings, and can make adjusting the valves tricky.

i dont have the cams on yet.... i can still do the check.. but if they are loose how does removing material help? THAT doesnt make sence.

can i get the tool to remove the material without spending a bundle or do i have to get a machine shop to remove some for me?

There seems to be a lot of owners who rebuild engines without any experience. Fwiw this isn't wise. You should have someone experienced helping the first few times you do it.

my dad is with me. hes giving pointers and opinions and a helping hand for the stuff i cant do with two. I dont see what i need such an experianced person for. I'm fairly knowledgeable about cars and its not like i came into this not knowing what a piston is... i am pretty good finding my way about things and so far i've gone really...really slow and done my best. i dont know what more i could do. i'm sure as heck doing a better job than the person before me. stripped studs cheap gaskets and sloppy application are all taken care of and now i just have to check my valve clearance and maybe check my cam bearings.

All i've done is replace the headgasket...and i couldnt afford having a shop do this so i'm doing it myself. And i'm not really rebuilding anything. i tore something apart, cleaned it, installed new gaskets and some hoses and i'm re-assembling it. I can check the parts, but my engine doesnt have a lot of miles on it and i cant exactly afford new parts anyway. my engine ran fine before the teardown... just had BHG symptoms... My dad has worked with engines and he is there to give opinions and help when i need it. I've been told my engine sounded nice and it seemed healthy beofre all this. I'm trying my best here and telling me i should have someone experianced with me this late in time is almost upsetting because i cant turn back and i've done all the hard stuff already.

I tried my best for help on here and thankfully most of my important questions were answered.:icon_razz

I'll start a poll for the how long till "My car blows smoke on deaceleration" post!

do you honestly think that will happen to me? :cry: :nono: :aigo: how long does it take for that to happen on most supras? I have the valve seals...i can probably do that myself later on if i have to...maybe.
If changing the seals is considered a valve job i asked my engine shop and he said he wouldnt do one on my head... hopefully that counts for seals as well as machining the seats.:3d_frown: thanks for keeping my hopes up:cry: i think i could have done w/out that.

 

[IJ.]

Valve seals exist in a very hostile environment (esp on the exhaust valves)

It's insanity to not change them while a head is off!

 

[Figit090]

too late then. i thought it was part of the valve job idea... he said i didnt need one and i didnt know. is there a difference between getting a valve job and changing the seals?

can i do this while the head is on? i heard its not easy. this is upsetting..i've done everything the best i could.

 

[IJ.]

There are ways to do it but I wouldn't suggest any of them for a novice to try sorry.

 

[Figit090]

so...the usual life on the seals??? anybody?

IJ why the heck does it say you're offline but obviously reading this as i type.

 

[Figit090]

you know...as my dad keeps telling me...i should stop worrying...it wont help me at all. i should just get the damn thing done.

nothing i can do now anyway. thanks IJ.

 

[IJ.]

I'm invisible
(I'm only a figment of your imagination I don't actually exist)

 

[Figit090]

oh ok.



......lol.

 

[suprahero]

I'm invisible
(I'm only a figment of your imagination I don't actually exist)

I knew it!!!!!! I tried to tell MKIIIVixen that, but she didn't believe me..........:biglaugh:

 

[IJ.]

I'm an answer bot program that runs in the background

 

[mickyg]

I'm an answer bot program that runs in the background

LOL!!!

Fig, am I understanding correctly that you never disassembled the valve assembly from the head?

To answer your question about valve job vs valve seal replacement, they're not mutually exclusive but you can do one and not the other. A full valve job involves removing the valves, regrinding the seat (part that's in the head) and the valve as well, replacing the seals, making sure the clearance between the valves and cam is correct, machining the valve if it's not, etc...

You could have replaced the seals and not done the rest and that usually works fine if everything else is OK. Actually, it's what I plan to do because my valves look OK and I can't afford a full valve job.

 

[mickyg]

i dont have the cams on yet.... i can still do the check.. but if they are loose how does removing material help? THAT doesnt make sence.

can i get the tool to remove the material without spending a bundle or do i have to get a machine shop to remove some for me?

Hah, this one had me too! Funny how the mind processes this sort of statement. Here's how this works: the flat portion where the cap mates to the head gets a bit taken off, this ends up closing the gap between the cap and the head. You end up with a slightly distorted circle as a result but there's usually only a small amount being removed and so the distortion is minimal.

Make more sense now?

 

[3p141592654]

Good explanation mickyg, and given that the cap is already egg-shaped if it shows excessive wear because the loading on the cam bearings is to first order inline with the springs, removing material actually pulls them back closer to a circle.

Fig, the issue everyone has is that 90% of the effort is done if you already have the head off, and since the valve seals tend to harden up with heat, you should have replaced them. You would need a valve spring compressor but there is a nice one on Epay for about $50 that has the deep recess you need for the 7M head, or maybe your dad has one already.

The life of the seals is probably about 5 years. My 7M was blowing blue smoke on cold startup after it was about 5 years old and had 40k miles.

You don't need anything fancy to lap teh bearing caps. A flat plate and 2000 grit sandpaper will work if you are doing it on the cheap. You will need a micrometer to measure how much you remove, but cheap chinese ones are everywhere.

 

[Figit090]

Hah, this one had me too! Funny how the mind processes this sort of statement. Here's how this works: the flat portion where the cap mates to the head gets a bit taken off, this ends up closing the gap between the cap and the head. You end up with a slightly distorted circle as a result but there's usually only a small amount being removed and so the distortion is minimal.

Make more sense now?

OH yes it does. yeah the other way would be...uh...stupid? lol. thanks.

..............You don't need anything fancy to lap teh bearing caps. A flat plate and 2000 grit sandpaper will work if you are doing it on the cheap. You will need a micrometer to measure how much you remove, but cheap chinese ones are everywhere.

ok, thanks. now that i realised how this is done it seems much eaiser. i did that do my EGR cover because someone ruined its surface.



I have another question about the valve clearance...i think its the only check i'll do besides maybe the bearing clearance that i will do... i dont see the proper specs in the TSRM that would tell how much gap there should be between the cam and lifter shims when that valve is shut... i think i understand the method... stick a thickness gauge inbetween and check. engine shop told me about it but its the only thing i dont see in the TSRM.

 

[Figit090]

oh and one more thing... what do you guys think on the torque in my situation? I've heard lots of different things. i wont go higher than 72ft/lbs because i've read that webpage on the bolt tests done on 7m head bolts.

right now its been sitting at 60 ft/lbs for over a day. i'm wonding what i should do before i finish assembly. i was thinking of backing off one at a time enough to break loose and re-torque one-by-one in the proper order. or should i crack loose all the bolts in one sweep and THEN tighten them in order? this would be the final time before assembly...then i'll wait until after 10 heat cycles.

thanks for your help guys!

 

[mickyg]

I have another question about the valve clearance...i think its the only check i'll do besides maybe the bearing clearance that i will do... i dont see the proper specs in the TSRM that would tell how much gap there should be between the cam and lifter shims when that valve is shut... i think i understand the method... stick a thickness gauge inbetween and check. engine shop told me about it but its the only thing i dont see in the TSRM.

It's kinda hidden in the TSRM - you can check my build thread for what I measured as a comparison but I'll find the TSRM page details and post those up shortly. You check the distance between the shim and the cam lobe when it's pointing away from the shim - just in case you didn't already know that.

You'll find details of valve clearance measurements here

 

[mickyg]

oh and one more thing... what do you guys think on the torque in my situation? I've heard lots of different things. i wont go higher than 72ft/lbs because i've read that webpage on the bolt tests done on 7m head bolts.

right now its been sitting at 60 ft/lbs for over a day. i'm wonding what i should do before i finish assembly. i was thinking of backing off one at a time enough to break loose and re-torque one-by-one in the proper order. or should i crack loose all the bolts in one sweep and THEN tighten them in order? this would be the final time before assembly...then i'll wait until after 10 heat cycles.

thanks for your help guys!

I'd go 70 ft/lbs (or even all 72). As for the backing off of torque, that's up to you. Would hurt to turn 'em all out half a turn (make sure you follow the proper loosening sequence) and retorque to 60/65 then make a final pass to 70.

 

[Figit090]

BAD news all..... and thanks mickyg for your help.

OK! well... i havent touched the head because i was running around getting oil, filters, and new belts (no timing belt this time around) and when i got back i was bolting on the exaust......and what i feared happened......

2 more studs stripped.::dead horse:: i had a fear of this AND i have read pleanty to convince me to do helicoils but then money and the possibility that it might be fine (engine shop probably hasnt seen OUR heads much) made me sway away from them when i had the head off and in the shop.:dunno:

now i'm going to do the two i just stripped and fit new studs and then maybe the other two ...but i think that the other end of the head is better. i successfully got to the 29ft/lbs on the frot studs (new toyota parts) and then on my way tightening the other nuts i got the heart-breaking feeling of not feeling resistance. :cry:

so i have the two stripped studs out and i'm getting the helicoil set tomorrow...

if anyone has done this and can tell me what set to get i'd appriciate it. i'll be spending the next half hour researching the proper size to get and then how to do it while minimizing error. I know there isn't room for much or any in this procedure. and incase you might mention it..i'm not taking the head off...i'm doing it IN the car.

.....and any tips you can give on the best approach to remove my exaust manifold IF you think i will need to; are very welcome. its a tight spot. i'm applying super penetrant tonight so it can loosen up. i'll try from above and below but i tried a while back and they feel really tight. we'll see tomorrow.

This is a minor setback...real bummer that this happens so late in time but I have to buy a new ISC valve seal anyway so a stop to the toyota shop isnt too much outta my way. (yes i didnt think and just unbolted it...first timer and that was my only OOPS that i can fix without buying more stuff.)

thanks again everyone, i'm almost there. :icon_neut

 

[3p141592654]

Take a look at this thread before you proceed!

http://www.supramania.com/forums/showthread.php?p=165412#post165412

 

[Figit090]

thank you that helps a lot.

we have a 90 degree adapter but dad says its crap...may need to buy new if this is true.

didnt think of the lube...definatly need that.

i take it 10mm is what i want if i'm sticking to the stock studs (new parts)

I already bought some new studs and they have a considerably larger amount of thread on the side that goes into the head... probably part of the reason our heads strip along with the severe heat... i cant imagine why they would install such short studs... obviously they re-worked their planning but...sheesh.