How to PROPERLY rebuild a 7mgte by KMP

[HKS_TRD]

I'll now talk about engine rebuild and what to ask from your machinist...

Mandatory steps:

Face head
Face block (don't forget the timing cover when facing the block)

Block decking.
here there is a rule to respect. you want to end up with a piston to head clearance between .035 - .040. For exemple, my head gasket thickness was measured like that:
3 layers : .007,.031,.007 (.045 total)
so to have a piston to head clearance of .040 pistons had to stand out of the block .005 at TDC.
so remove enough material to respect this pistons to head clearance.

Few points here:

1. Regarding the machining, you left out the part of having the timing belt tensioner installed and torqued to factory specs when doing the machine work because otherwise bore #1 will be distorted out of round when you assemble the motor

2. Regarding the piston to head clearance, having the pistons protruding further from the block is NOT a good idea, if anything you should be having the pistons custom made with offset pins to work with the new deck height if your block requires significant machine work

3. No mention of a torque plate

 

[JDMMA70]

Straight 6 engines have a good static balance naturally by design. Im not sure how that makes it not well balanced. A dynamic balance certainly couldn't hurt though.

 

[Nick M]

Pressure and flow are intimately linked

When it comes to oil, temperature changes both.

If you try to pump a large volume of oil such as a vehicle oiling system, and there isn't anywhere to go, pressure goes up because the space it is trying to consume has not changed. And as such, flow goes down. An engine only needs a certain amount of oil. Not to say that is a little or a lot.

 

[debrucer]

Few points here:

1. Regarding the machining, you left out the part of having the timing belt tensioner installed and torqued to factory specs when doing the machine work because otherwise bore #1 will be distorted out of round when you assemble the motor

2. Regarding the piston to head clearance, having the pistons protruding further from the block is NOT a good idea, if anything you should be having the pistons custom made with offset pins to work with the new deck height if your block requires significant machine work

3. No mention of a torque plate

For me, just another reason not to go so slowly in my build. The more I learn, the more I learn I've done it wrong. I knew about the torque plate, and went without one. I never heard about point 1 before. Very interesting. Thank you. Where once I wanted 600 rwhp I am now going to settle for 450 and just hope she holds together

 

[atmperformance]

just as i'm about to put my radiator back in you hit me with this oil mod. I have the smaller 7163 ready to go into my car but I'm strongly considering the under drive pulley.
I will say the worst thing that happened to me on my engine rebuild was when i was told the block was decked and i replied with better not be because i don't see the timing cover bolted on. their plea to let the cut the cover off the engine did not please me.

 

[karlou426hemi]

7163, that a freaking great match for a street oriented car !!!!!

 

[IndigoMKII]

Especially with a QSV.

 

[atmperformance]

Especially with a QSV.

we joked it might spool like a stock ct26 with a cat but that might beat it.

 

[nosman4]

Just a note for everybody considering this smaller oil pump drive gear, it is possible to make this work, but..... If you are on a standalone EMS, it WILL change your timing by a degree or two. I just went to put the one on that I had made and guess what, I can't unless I want to have it retuned. If the gear was a tooth or so smaller it would be perfect, but I'm gonna have to wait till next year when I have the car tuned for some more mods.

 

[karlou426hemi]

If you are on a standalone EMS, it WILL change your timing by a degree or two. I just went to put the one on that I had made and guess what, I can't unless I want to have it retuned.

Not only if you're using an EMS, it will change you're timing even on the stock ecu. personally I don't think that 2 deg of cam timing will enough effect you're tune that you can't do this mod without a retune, on my vvti 1jz moving the intake cam 2-3 deg barely do anything on the dyno.. but 7-10 deg start to make some changes..to gain around 15-20% trq in midrange, I advance my intake cam by 41-43 deg so do the math, if 40-43 deg need 15-20% more fuel I don't think that 2 deg will affect the tune a lot.

Obviously changing the timing belt length and oil pump gear diameter WILL probably change your cam timing a bit....
Ajustable cam gears will take care of that....I don't have these on my engine because after machining the cam timing is dead on the marks.
But personally if i were you i'd invest in ajustable gears just to have some level of control on my power band shape

 

[nosman4]

I understand that having adjustable gears would fix this, but being that I just had the car tuned a few weeks ago... I am going to wait until next summer when I have larger changes to account for a retune. It might be a good idea to edit your original post about the gear change and add that it will change the timing, just so everybody knows.
EDIT: I was just looking into this more tonight and found that you can correct the timing difference by switching the pins in the cam gears to the left position instead of the center. It adjusted the gears just about perfect to maintain factory timing. Just thought I would share my findings.

 

[debrucer]

I have a question about this picture...



What is going on here? I presume we understand to use a "chase" not a "tap" to clean the threads before assembly.

What I question is... err, using a power tool? Aren't you afraid of ruining the threads?

 

[karlou426hemi]

no it is a tap you're right here. This is what i find the best for cleaning threads.
Yes i drive it with a drill and some tap fluid and no I've never ruined any threads using this method....

 

[AGsupra]

I've used power tools to chase threads for many years, and have done hundreds of them.
If you don't think you can handle it, then don't try it.
Evidently OP can handle it.

Karlou, any updates on this ?

 

[limbodk]

I have been looking for a good undereason drive pully for years, thanks for doing the hard work. Can you give more details on what mazda engine you took the cam gear from?

mazda protege 1.5 or 1.6 cam gear.

gives me a range of like 30 years of engines to try. I am off to the car scrap yard this weekend and really would want to grab a gear if I can.

Engine code would be great, but year and what country you live in would probably do it too.

 

[RacerXJ220]

I am a huge fan of torque plates for boring and ring gaps.

Part of doing it right, especially if you are going to torque down to 90ftlbs, or what many people recommend.