All Failed Rebuild Respond!

[Shytheed Dumas]

I would like to understand what had caused rebuilds to fail. If you respond "Failed - reason known or reason suspected", please say what failed and why, and be as specific as possible. Also, please indicate after how many miles after the rebuild was complete. Who did the block/head work?

If rod knock, then why? Generic bearing tolerances instead of Toyota tolerances, insufficient cleaning, etc? Had a BHG?, then why - MHG/composite with what amount of machine work and/or boost? Improper break-in? Leaky valves? - Didn't replace guides or even seals?

The main thing is, I would like to know what went wrong - the easy. Then I'd like to know why, which isn't always so easy, but lets here what you at least think went wrong.

If your build failed, be honest . Understanding what typically goes wrong will help everybody know where to spend the most time and money on builds.

Thanks,

-Kurt

EDIT: Damn - should have allowed multiple choices for anybody who built/failed/rebuilt. Mods????

 

[Poodles]

I've had two builds on teh same motor, but the block wasn't touched...

got a instand BHG because the head was eroded so bad, went cometic MHG and got another head rebuilt and been fine since...

basicly, don't cheap out, and find a place that knows WTF they are doing...

 

[Shytheed Dumas]

Thanks Poodles - So rebuild failed, reason known - insufficient head machining/bad head.

Just what I was looking for.

 

[DaSuprawolf]

i got like 7K on my rebuild, did it all my self. BHG, so i just did rings and bearing too.
just some annoying oil leaks now.

but all is good, runs great.

 

[AJ'S 88NA]

One failed due to not enought oil to rod bearings under hard braking and cornering.
So far this one has held up, 4k miles, shimmed oil pump, and added 2" to oil pan with baffles, but haven't had it on the track yet.

 

[supra_ed]

god.....long story short me and two buddies of mine (3 7ms total) had a rebuild gone bad because of asshole machine shops who didnt know what they were doing. take it to a shop who has proven experience with supras, or at the very least with respected import performance. you get what you pay for.

 

[Shytheed Dumas]

^^^ Specifics? I'm guessing you had RK pretty soon after the build?

 

[sterlingae]

nice ive been waiting for a thread like this had a machine shop prep my block and head cleaned everything put it together with a stock hg lasted like 600miles and swaped in a cometic, jumped the gun on putting the cometic on:3d_frown: , been on for about 200 miles............faulty oem hg????:1zhelp:

 

[JustAnotherVictim]

Glass beads are bad for your engine k.

 

[GrimJack]

I blew up one of my rebuilds. Reused pistons that had seen some bad detonation - they looked and measured fine, but they sure didn't last. When I tore it apart again, a couple pistons were missing large chunks of metal from the ringlands. I keep them around as pen holders to remind me not to cheap out in the future.

 

[Poodles]

machine shops around here take badly damage pistons (ringlands collapsed, ect) and make card holders out of em...

 

[flubyux2]

i voted "Yes, no problems". ive done a few other rebuilds. one of which is in RTA Supra's old red 91 turbo which recently was sold. i dont konw who owns it now.

both motors include:
Stock pistons, 0.5mm overbore, cryo treated, moly rings
stock rods
ARP rod bolts, honed big ends
Stock 7M crank micropolished, NOT CUT!
ARP main studs
Full blueprint and balance to 0.5gm tolerance on recip assem, RTA's build only
Clevite 77 std size main, rod and thrust bearings
AJUSA full gasket kit
ARP head studs, torqued, relaxed, torqued, relaxed and final torque to 95lb/ft
HKS 2.0 bead gasket on RTA's build, Cometic 2.0 on mine
block deck Precision surface ground on RTA's build, standard fly mill on mine
blocks cleaned, magnafluxed, align-honed mains
Inspected Oil pumps, reused, reset pickup head height, shimmed relief 12mm
10AN oil pump discharge hose to block, RTA's build only
Head stock port, fly milled, full rebuild on RTA's build; Full port, fly milled and full rebuild on mine

Break-in:
RTA's build. average around-town for 30 miles. Alot of 60-15mph no spark/fuel decel's at WOT. 85-40mph Decel no spark/fuel at WOT down hill, approx 1 mile (Skyway bridge between St. Pete and sarasota). rings seated in no-time flat. by the 800 mile mark, oil was still golden with minimal fuel/soot contamination.

My build. average around town driving, low boost for 400 miles, i guess. then upgraded to 60-1 CT and beaten on the freeways of Tampa by Bucsfanatic59. i currently have maybe 6000 miles on it now, compressoin is 167-171psi across the board. on the second oil change and oil is barely browned from contamination. no raw fuel smell on the oil either. no mechanical noise except from top end. i cant tell if its valve tap or just valvetrain harmonics echo'ing up my ported intake manifolds and resonating in my 4 liter surge tank... the wall thickness is only 0.125" so IDK.

hope that helps.

 

[annoyingrob]

The last build of my 1JZ failed in an impressive way.

The motor had a hard life before I got it. This was evident by the knock it had on startup. when I went single, I decided to rebuild the bottom end. Proper sized bearings fixed the knock, but I forgot to change the thrust washers. The 3200lb pressure plate didn't help the worn thrust washers either.

a few thousand kms later, the thrust washers finally had enough, and FELL OUT. The motor seized on the highway 700km away from home (at Suprafest of all places )

Lesson learned. Now I have a 1.5JZ (soon to be full 2JZ), with new thrust washers, and no crankwalk

 

[Poodles]

chock up another engine death to RPS...

 

[pimptrizkit]

i hammered out a set of stock rod bolts and hammered in my arps, i got rod knock platigue gauged good o38 or some where around there.
~ i ended up beatin one rod to hard and made it out of round? thats all i could figure out, took less then 600miles to start makin noise

on a head gasket replamcent i had the head machined and didn't do the block and i had low spots my innffere tools didn't pick up and it over heated, after boostin hard.

took about a month before it started over heatin while and after boostin.

 

[Doward]

OT, but I was down in your neck of the woods just 2 days ago, Flub! First time ever on I275, didn't know it was a toll road - WTF is with the bridge though? Seemed like I crossed Tampa Bay twice or something!

 

[TurboWarrior]

MHG (Cometic) was installed by a local machine shop. It is leaking. The forum informed me that it is a retaining rivet, left in the gasket that did not allow it to crush down.

Rebuild 2 is happening this fall

 

[Freshmaker]

I voted for my old supra, I was 17 at the time.

It was a BHG rebuild. I got the head "professionally" rebuilt and milled. I didn't know anything about machining at the time, but they did a horrible job. The RA was terrible. If I had known what I was looking at i wouldn't have put the head back on.

When I put the head back on with a MHG it leaked right away. I had to sell the car and go to college before I got another chance at it.

 

[flubyux2]

it seems like only half the machine shops actually understand that block and head surface finishes are important. some places just think they chuck it on the mill table and get it flat and its good to go, regardless of finish.

Doward, thats cuz you did! lol... I-275 crosses Tampa bay and goes into the north side of St. Pete (By my first apartment complex!) goes south and then takes you to the Skyway, thats the only toll part of I-275 itself. that route you took makes up some of our Supra-meet cruises. you probably couldnt see it, but the First time you crossed tampa bay, Gandy bridge was on your left... most of the races happen there. To your right are 2 bridges, Courtney-Campbell (more races and chill spots) and Bayside bridge (shorter but 170mph sprints happen there too)

that toll bridge you crossed was actually the one i broke in the motor i mentioned above, lol