Montero Pistons work great!

[El_Rapido]

Well, I finally found out by myself if putting higher compression ratio pistons in my car would benfit it or blow it up.  I took the Pistons out of a 1989 Montero and took them to get cleaned and balanced. I took a cylinder head out a 1988 Mitsu Truck and took that to get ported and poliched with a five angle valve jo + resurface.  Then I eliminated the Balance shafts, repalced the timing chain, cam pulley, the two guides and chain tensioner.  I then ported the throtle body and removed the air splitter in there.  Balanced the crankshaft and polished all the contact areas.  Well, I put everything back together and decided to add mechanical rockers from a caravan and adjusted them to.006 with a feeler guage.  Finally I finished and turned the car on.  Worked like a charm.  With the 1G MAF and rerouted piping it seemed to work perfect.  Well, after a month of breaking it in I took the car to the track.  My best time was a 14.8 in the 1/4 mile at 5,400 ft of elevation.  I had trouble with traction as the tires were spinning like crazy of the line and I was having trouble shifting to third.  I suspect that the could easily run mid 13's with slicks.  Considering I used my stock exhaust, no fuel system upgrades (except Venom Injectors), street tires and stock repalcement clutch. not to mention my shocks are gone and the car was rocking like a boat.  I think that if I invest in all of the other stuff I could be running high 12's I kid you not 8).  Now I know that it is all about taking risks, and when they said my cyl head would blow off I said "SO." With MPI man and a 16g. Oh Man! Watch Out! ;D

[vitamincj]

How much boost were you running?

 

CJ

[eeaston]

And the other big question- What compression ratio did that give you?

[pumpedTSI]

Those montero pistons are not designed for sustained turbo boost and will eventually fail especially with a bigger turbo and higher boost.............one lean out and that motor is toast.......

[ChadC]

what mile per hour did you get with your 14 sec run?

[El_Rapido]

See, I did the T-Racing mod where you put the T fitting it the waste gate vacuum line and that made me run at 14 psi, I then regapped the sparkplugs to .032 and advanced the timing to 9* BTDC.  I also did not have time yesterday to list some of the mods I do have like ported exhaust manifold, intake manifold is also ported.  High flow fuel filter, gutted pre-cat.  See, I have seen turbo cars run compression ratios up to 11.0:1 with engine management.  The conquest factory compression ratio is 7:1 and the Montero has a compression ratio of 8.7:1 but in reality the true compression ratio for my setup is around 8.55:1 with the porting and polishing and the valve grind.  Now, engine damage occurs only when the temperature in the combustion chambers is to great and this causes the air/fuel mixture to ignite prematurely or burn a hole thorught the piston :-X, ...but... when the tempurature of the mixture in the combustion chamber is reduced then it becomes really efficient.  All you need is to have proper airflow, good intercooler, and heat guards and you will be just fine.  The pistons from the montero are made of cast aluminum and will handle a great amount of abuse. When I got the 14.8 run I was going 91.23 mph, my 60" was 2.0123 and the 1000" was 13.03.  All I know that if you are not breaking parts, you are not racing. ;D

 

P.S. It can handle 14 psi, if you dont think so, too bad.

[eeaston]

I don't think 8.5:1 is unreasonable at 14 PSI.  Most people running non-stock pistons are between 8 and 8.5.

[pure_insanity]

I don't think 8.5:1 is unreasonable at 14 PSI.  Most people running non-stock pistons are between 8 and 8.5.

 

 

i do hope this is right as the motor im building is going to be abut 8:5.  my other quest was running a truck motor which is around 8:5 or 8:7(dont honestly know) it would eat my other quest for breakfast and not think about it.  higher compression really makes a difference.

[Metric-man]

El_Rapido

 

I'm pretty sure you are talking about the 4cylinder Montero G54B, but the Montero also came with a 6G72 V-6 which used the same diameter pistons.

But I have to ask because there is no mention of the engine size.

[Dcrasta]

Rapido..

 

What elevation you at?  High elevation effectivly lowers static cr..

Might be a different story down near me (Sea level)

[Technology]

and advanced the timing to 9* BTDC.

 

P.S. It can handle 14 psi, if you dont think so, too bad.

 

 

you retarded the timing if you set it at 9 degrees before top dead center.

 

as long as you don't lean out, that's sweet. watch out for numero tres piston, that one gets hotter than the others because of poor intake design.

 

get a big exhaust or a cutout or something. that will help a lot.  by now, you should have eliminated your emisions. so if you haven't removed your EGR valve and related equipment, do that. remove the A/C stuff too.

[Noodle]

El_Rapido

 

I'm pretty sure you are talking about the 4cylinder Montero G54B, but the Montero also came with a 6G72 V-6 which used the same diameter pistons.

But I have to ask because there is no mention of the engine size.

The 6g72 is a 3.0 Liter V6

[partsquest26]

Rapido

happy to hear the piostons work i always wondered if they would hold up

some say they will fail and like anything sooner or later it will im sure but i wouldnt worry to much about it, my wife's white quest she is bracket racing has a stock bottom end with polished combustion chambers to help reduce detonation jet valve plug's a schneider 284 cam with roller rockers that seems to work fine so far, hard pipe's and stock intercooler with a TD06 20G pushing 23PSI with a 1Gmas and no added injection upgrade's only a bosch pump and a cartech riseing rate regulator ,doesnt run lean at all It has a wide band O2 to monitor the mixture and a EGT gague that stays at or below 1300 deg in 4th under all that boost holding it and after all that it runs in the hi  midrange to low 12 teen's depending on traction from the street hoosiers witch is not very good in 1st or 2nd ,it  has been  holding together for the last 2 years and no internal problems yet and i do not forsee any, so keep the pedal down and like i told my wife if it breaks its was a fun ride getting there right !!!  ;D I dont suggest to anyone who has no means of replaceing their engine running this boost on a stock bottom end but myself i feel nothing last's forever and if you have to always feel afraid  about it you may aswell not run hi boost or drive it

I am sure there are going to be those who are skeptical and if anyone doubt's this i would be happy to prove it or mabye i should say my wife is the driver so she would be happy to prove it as soon as the great lakes dragaway here in union grove wisconsin open's on the first day of bracket / points racing season starts she will have her's there this year aswell as mine  feel free to come watch

 

so keep the hammer down like there is no tomorrow

Later

[smog]

Whats wrong with 8.5:1

 

People running supras, and 4f63s run that high of compresion and are drunning around 23lbs of boost on 92octane.

 

Why would it be any different for us?

[Funky Phil]

I dont see what would make 8:5.1 so bad. I just think that everyone else runs 8:0.1 and it works and noone here is willing nor has the cash to go do any experimenting. I think 8:5.1 would work great.

[pure_insanity]

i ran a truck motor which has 8:5.1 with about 10-12 lbs of boost and no oil squirters.  it survived whatever i put to it till it ran out of oil and tossed a rod thru the block.  i saw no problems whatsoever with the compression.

[ALANFROMPDX]

Guys....all these cars from saturn to honda with good times are running higher compression pistons.

 

engine management is the key.

 

Probably would blow our motors up because we have an uneven fuel distribution.

 

throttle body is junk and all manufacturers know this.

 

I feel throttle body with turbo to be crazy.

fuel needs to be distributed equal.

2 y's ain't equal.

 

if we had all info on the blown motors i would bank there would be some similarities with which pistons fail over others.

 

I have been doing research on all the other cars and watching all i can.

I am expanding 1 of my directivos tonight due to the wealth of shows on satelitte relating to cars.

 

I am not looking to follow the masses but crunching numbers from everyone else.

El rapido WELLDONE.

 

thinking out of the box is the only way.

[Dcrasta]

My next motor will probably be closer to 8:5-9-1 but with MPI .  More static compression does give you more out the box but seems to limit how much boost you can run.. No doubt Mitsu used the lowered compression as a safety margin to compensate for the TBI .

[vengeance484]

when i rebuild my engine, i'll also be going to about 8.5ish:1...

 

if you think about it, the montero pistons aren't any different from our stock pistons other than the fact that they're higher compression. they're cast aluminum, as are our stock pistons...no difference in how they were made or the materials. only thing that makes forged better - forged are made of layers of aluminum rather than being cast into their shape...this makes the forged able to hold together better and take more abuse...

[Starcon88]

There is no reason we can't run 22-25psi with a 8:1 or 8:5 compression piston. PLENTY of DSM guys run that much boost on a 9:1 compression piston (I am talking about we MPI questers not TBI). I have even seen a few DSMers run 10:1 compressioin with 20psi on 20Gs and they have zero problems. As long as you are cooling that incoming air enough and don't knock your fine. I am planing on running 20psi with 8:2 compression when I finish with my motor and maybe if it likes 20psi I might push it up to 25psi.

 

       Kurt

 

P.S. I'm also going also talking about upgraded heads too not the factory ones. I'm not sure our factory heads will cut it but they might I don't think anyone with MPI is running factory head and a ton of boost.

[Dcrasta]

Okokok I have been thinking why compression might be a good thing..

 

1.  Cam profiles (more aggressive lift and duration) effectively lower static compression (lower compression #s and engine vac after just swapping cams seem to indicate this..)

 

2.  Raising static compression during rebuild to 'compensate' for lost 'cylinder pressure' can 'make up' the loss of static compression due to cam swap.

 

3.  Raised static compression + matching cam upgrade = higher VE for the same displacement..

 

4: This allows you to burn more fuel and make mo power!  Makes sense right? and you are not 'raising' the detonation threshold because your effective cylinder pressure is staying relatively =

 

Im starting to think that flat top piston idea professor had a while ago makes more sense.. the cam-C/Ratio combo really makes the 1-2 punch.. Add that up to some RPMs available from the reworked cam profile and you get the knockout..