n00b head gasket - head studs and boost Q

[-Nemesis-]

Been doing a bit of reading tonight about headgaskets as i'm about to boost my 1UZ to around 7-8psi ideally. Now i'm very close to finishing my project, though i've all of a sudden become paranoid about blowing out a HG after seeing spf_lexus do it (and I think you did too Steve yeah?)

I don't really have the desire, time or funds to pull the engine and do a big head gasket job as preventative maintenance although I know that's ideal.

From searching the net tonight I read something about 7mgte's blowing HG's because the heads aren't torqued down enough and it just gave me a thought, which may seem stupid... The thought came about because at the moment I have all the plastics and throttle body off the top of the engine already.

.

Stupid Q A: Can I access all the head nuts just by taking the rocker covers off?

Stupid Q B and my possible stupid idea: Will I get any benefit from simply retorquing the heads without removing them? As in reduce the chance of blowing an old head gasket? Maybe even tighten them a smidgeon more than they are currently are to increase the clamp pressure a tad?

Waste of time?

 

[Lextreme II]

Stupid Q A: NO

Stupid Q B: NO

 

[spf_lexus]

Nem- I share your fears lol... I beat the hell out of my 1uz and thats the truth. I picked her up w/ 125,000 and ran her very hard for another 75,000 w/o any major problems. Once the blower went in I didn't take the steps to prevent too much stress. I noticed that the stock line pressure wasn't high enough for a supercharger, and mine was too loose. What happened was when I took a friend out in her I looked down to check my boost and I caught my Tach revving just over 7,000!! basically the tranny cable wasn't tight enough to keep the engine revs down. Once i tightened 2 full twists it never goes over stock rpm..

This is the reason i feel my driver side went. Actually a few days after the over-rev i noticed a very small oil drip and one day i had a small cloud exit my tails upon startup. I had the symptons of a going gasket but I just rode her hard until one day I challenged a freeway on-ramp and held WOT until i was in the fast lane.... I let off once i hit 100 but it was too late, HUGE... AND I MEAN HUUGE!!! amounts of smoke out the tails... I dont want to scare you I think it's kinda funny. It was so bad the inside of my cab was filled w/ white oil smoke and I could barely see out of my front window lol. I got home and it looked like a kid took a garden hose to my back bumper... oil evenly sprayed all over.

I feel you should be fine Nem, just dont over rev, and boost for long periods of time, I had 3 of my 5 gears pinned and full, steady boost after i hit 25mph all the way to to 100mph but it was clearly the 7,000rpm boost, it was so obvious.

Bottom line: Increase your line pressure to the tranny and that should keep th revs under control. My 200K gaskets + 7K revving + Mr. lead foot over hehe. i took them out and the passenger side was is perfect shape and so was the driver side front 2 cylinders. the rear two were washed clean from the coolant. it looked really good actually, I would slowdown on the freeway and let the engine calm down and the smoking went away, and i had to drive another 15min w/ blown gasket and made it home pretty easily.

This weekend I get my garage for my apartment so i can re-torque my bolts. Unlike yous mine still haven't been torqued correctly. Drove her 1200 miles w/ only an oozing corner that won't drip. Basically after looking for the elusive specs for MLS + APR studs the finished torque is 70ft/lb I fiished at 45ft/lb !!! that means I have 25ft/lb loose, thats quite a bit so i need a 2-step torque increase. I sorta ignored the 29ft/lb + 1/2 turn... that 1/2 turn basically doubles your torque and i didn't even bother.... amazed I haven't spewed all over yet, I guess the MLS isn't so bad.

 

[XR8tt]

Bad tune will kill any head gasket..
Engine issues with forced induction is usually detonation...
High boost levels can be heads lifting due to head bolts being weak ..
This eventually blows out graphite gaskets..

 

[spf_lexus]

No graphite here... MLS this time. Also I never tuned, just used a RRFPR at 12:1 and never heard any signs, ran very strong.

 

[-Nemesis-]

I wont be running really high boost, just a bit worried because the gaskets are from 1992...

I was going to aim at 8psi but now i'm wondering if I should be happy with 6 or so. I don't wanna get stuck halfway to nowhere towing the caravan off road and blow a HG...

 

[-Nemesis-]

Are their any head gasket walkthroughs or manuals on the web? I had a complete Toyota (yes all!) workshop manual on cd but the disc broke

Actually it was a bargain. I bought a workshop manual CD off ebay years ago for like $7, was advertised as the 4Runner manual. When it came it was the Mitchell On-Deman program with a Toyota data CD, with every Toyota on it! Spewing the cd broke (the silver bit with the data just flaked off one day)

 

[spf_lexus]

Nem-I would give your HG's a try. You sound a lot like me lol, 1st time taking 1uz apart? It's not too scary but there's a couple tricks to you need to know.

1. The cams are relatively easy, just remember to lock the scissor gear w/ a 10mm bolt. one of the "scissors" on each bank is pre-loaded and it's a bitch to get back if it looses it's spring. Oh and remember to remove after!! It would grenade the engine lol.
2. Mark the shims once the cams are out... just number the tops. I made the mistake of flipping my head upside down and all 16 fell out and i didn't mark so that meant a trip to the machine shop.
3.Timing, really easy if you have decent instructions, don't know if you have but i found that pre-loading the driver side timing belt as tight as possible to be even w/ the other side once the timing belt tensioner is tightened. If you get the belt over the driver cam pulley and crank and have the lines matched up the hard part is done.... just pull as tightly as possible over the passenger pulley and keep tension on idler while you tighten.


In all honesty it was more of a challenge of keeping track of bolts and the sequencing of removal/install... I am a noob, believe me and I managed w/o a manual, just Lex on the phone every 2 hours!!


As for boost, I am a steady 7psi and love it, i don't want to get boost greedy but I like where I am, I have to remember it's on an LS... not an SC, or even a 4-runner!! I have an extensive background around race suspensions for pre-running and I would LOVE a raced out 4-runner w/ a procharged 1uz. From how solid my engine felt at full boost I don't think 6-8psi should be an issue, just watch the revs, supercharger puts a strain on the rev-limiter just tighten 1 full turn on your tranny cable and it should keep it calm. I would not go over 8psi but not for HG issues but for the lack of fuel you are likely to get. All you need Nem is the rising rate hooked up correctly w/ the max 12:1 ratio and it should get plenty. Whats the rating on those hilux fuel pumps?

 

[stevechumo]

Been doing a bit of reading tonight about headgaskets as i'm about to boost my 1UZ to around 7-8psi ideally. Now i'm very close to finishing my project, though i've all of a sudden become paranoid about blowing out a HG after seeing spf_lexus do it (and I think you did too Steve yeah?)...

I redo the heads to increase the rigidity so I can boost more. :trink26: My goal is at least 12-15 psi. One of the main reasons the 1UZ blow the head gaskets is due to the engine being old. All of them are from at least 100, 000 miles and up. Even if you tune it right, the head gaskets still have a big chance to blow.

Your questions will have the answers of NO...lol If you can do it, do it and save headache later.

 

[-Nemesis-]

Nem-I would give your HG's a try. You sound a lot like me lol, 1st time taking 1uz apart?......

I'm not worried about the mechanic side of it, after all i've done engine conversions, built suspension systems, done timing belts, fitted custom clutch kits, done the shims on the 1UZ etc etc...

I just get the impression it's a monster job, especially now i've got all this LPG stuff strapped all over the top of the engine.

So you've got to remove the cams to get the heads off..... Sounds fiddley.

The fuel pump doesn't matter too much as i'm running lpg 95% of the time with it's own injection system.

I need the 4Runner on the road by the 21st this month at the latest, though my excitement for boost wants it going asap hehe...

What to do....

 

[-Nemesis-]

Thought # 2... Buy a second engine, new gaskets top to bottom and new pumps/belts etc.... Drop it in once done...

 

[stevechumo]

Make sure you'll take the heads off and reinstall them in the right sequence, or they'll warp and leak. Mark the cams and timing as much as you can, because they'll help you putting things back a lot quicker. I don't worry about them that much, but I personally worry about choosing the right screws/nuts when putting them back...LOL. I bought the repair manual CD (Mitchel) from Ebay for around $10. It's not as good as the original manual, but it's ok for most of the stuffs if you have the basic of working on cars and follow it carefully.