QG18DE rebuild project

[Xulfiqar]

It's a open challenge to you all nissan car maestro's. Invoke your knowledge build a engine with your nissan manual knowledge and then compare it with what I've built.. Thanks.

I have worked on engines more expensive than 200 of your nissan sunnys combined,, but physics and math dont change.

so which is it,
you installed 87mm wide rings on an 80mm piston?
you bored the block to 87mm? - 7mm overbore :-#

which market got the 90mm piston size toyota 4AF engine?

[Xulfiqar]

Hahahahahaha you guys should start designing engine for nissan cars.
No more comments from my end. I appreciate your suggestions and advices, thank you dears.
@QamarAhmadawan bhai yeh I'm being annoyed.
Commenting on pakwheels is very easy, bringing these machines in action is pretty difficult thing. I know what i am doing. My projects are always successful. This post was just to tell everyone that this engine can be built.

any econobox car production engine can be rebuilt, Nissan made thousands upon thousands of these engines in different factories around the globe - they even sell its repair manual as a "part no." which any mechanic can use, they sell every little bit of this engine in retail spare parts too.

[dani_kk]

I've mentioned it.
Collaboration with my mechanic and engineering work guys. The 80mm rings of QG18de were very loose in the cylinder walls.
I don't know how but the 80mm rings were very loose in my cylinders. QG18de's top ring is abit thick, the one i was getting was very thin. I tried rings of different Toyota engines. Toyota 4AF rings were bought.
On its box it was written 90x4mm.
When we dropped those rings in cylinder walls the Rings were slightly bigger so we had to trim them accordingly. And in the end the trimmed rings were adjusted with hair line gap between there cuts.
And then pistons were released in. I have not increased the bore size.

[dani_kk]

But you know this, mechanics are mostly illiterate they don't have any idea about manuals they work on there experience.

No one even tried to mess with this QG18de. Even mushtaq was telling us iski rings nai milti.
Ek hi solution hai get a new engine or block assembly.

[YamahaYB100]

It's a open challenge to you all nissan car maestro's. Invoke your knowledge build a engine with your nissan manual knowledge and then compare it with what I've built.. Thanks.

I don't accept your challenge because its Juggar and gets always fail in the end..like on iveco 8045 series engines some of them have 32 mm piston pin and some have 38mm but same 100mm bore and some have 104mm and lower size 32 mm pin and then interchanging parts and built a mule..and it was mechanic advise and after 3 months engine failed..
After that i replaced all parts to original specs and its 8th year with same engine without any problem...but no Juggar

[dani_kk]

I respect the senior members. But this is not the way, that I'm sharing some piece of information, and what I'm hearing from all senior members is leg pulling. No one is appreciating the work I've done. I've done the work we can have a meeting you can see the response, see the engine performance and everything. But this is not good that i hear challenging comments

[SER_GTR]

And @sergtr maybe I'm confusing to things up
Bore is still the same as it was.
Only head facing is done.
I thought honing is also consider as shaving of the surface of metal using machinery so i thought you're asking in that way.
As we know bore size is 80mm
When we dropped its current rings in to cylinder, they were too loose were slipping inside as if there's no friction.

So when we dropped 90mm rings of Toyota 4AF
They were like 3mm more in diameter. They were very nicely trimmed and were brought to approximately 87mm. So currently my bore size is on 87mm. And piston rings were too of some Toyota I'll state u it's name too soon. But that piston pin is very heavy duty as compared to its genuine ring.

This could've been played better if i could get QG18de genuine pistons. It would have genuine diameter of pin so QG18de piston would fit in easily but since piston pin cavity currently was widened Slightly so con rod was having pley in it. Creating noises. So I've basically restored my piston to work as new piston with good compression.

And those were black bolts don't seem tty bolts. They were as good as new. No expansion at all in them.

SO Let Me Conclude It..As I Am Not Getting It SERIOUSLY...I Mean SERIOUSLY...No Offence OP But Clarify These

You Said You Didn't Hon Or Shave Or Did Nothing....Means No Procedure For New Rings To Settle Not Even HON Marks No Cross Hatch???

2ndly....You Pls Read And Correct What You Write Above...... Bore Size 80mm....4AF90mm rings dropped to 87mm??? ...

.4AFE Dont Use 90mm...Its 81mm...And How COme You Make Them 87???? ANd Then Install 87mm In 80mm Bore...

Its Literally Saying You Installed 7mm Big rings in small bore.....this is Physically And In Reall Impossible.... You Must Be Mistaken With Numbers Or Being Badly Misguided.... Even 81mm Rings Can't Fit On 80mm Even A Bit Bigger Than 80mm Bore....

Qg18 Use TTY Bolts..Black/White... Doesn't Make Them NON TTY....They Are For One Use Only..Once Torqued..They Stretch And Is Useless For Next Time Use

WHat You Are Explaining Here Is Technically/Physically/Mathematically Impossible.......I Just Ask For Procedure To Help Others Not To Misguide Others ....!

And You Never Mention Break-In Procedure

[YamahaYB100]

I have worked on engines more expensive than 200 of your nissan sunnys combined,, but physics and math dont change.

so which is it,
you installed 87mm wide rings on an 80mm piston?
you bored the block to 87mm? - 7mm overbore :-#

which market got the 90mm piston size toyota 4AF engine?

Impossible....over bore and that too 7mm..i know once on bike engine i bored to 2mm over and the result was terrible with increased compression...every time i need to jump on kick to start up

[dani_kk]

If you got money, you got good knowledge, its your choice to do whatever you like to do on your machine. What i did is my experience my choice.
My QG15de was built like this.
It's been three years it working good. I. Gave that to a friend i can give you his contact you can visit and see his engine.
I don't just throw arrows in the air.

[SER_GTR]

If you got money, you got good knowledge, its your choice to do whatever you like to do on your machine. What i did is my experience my choice.
My QG15de was built like this.
It's been three years it working good. I. Gave that to a friend i can give you his contact you can visit and see his engine.
I don't just throw arrows in the air.

Its Not Abt Money Or Anything...Its About Information You Are Posting As "ACTUAL Information" Which Is Not Even Possible..Forget Helping....There's Nothing Wrong Correcting Yourself...

Else We All Know Its Your Motor...You Can Install 120mm Piston In 80mm bore by whatever mean Or NOT ...but don't share such as information and claim it to be useful...thats the Point...

Challenge You Sure You Are Standing On What You Posted???? Seriously Think ABout It

[dani_kk]

I'm standing on my words. I'll just say, do whatever you'd like to do. Thanks no more suggestions and your comments.

[SER_GTR]

I'm standing on my words. I'll just say, do whatever you'd like to do. Thanks no more suggestions and your comments.

Ok Fine...Let People Read And Think What You Write And Thing ABt Standing On Words...Mind It...Don't Even EDIT A Simple Post Of Yours NOW....! Let People Read It All..!

I Won't Reply On It...But Let People Do

[dani_kk]

I don't care about people bro.
You have declared a fatwa on my physics let it be like that.
People who need, my help will take it.

[saboor73]

I've mentioned it.
Collaboration with my mechanic and engineering work guys. The 80mm rings of QG18de were very loose in the cylinder walls.
I don't know how but the 80mm rings were very loose in my cylinders. QG18de's top ring is abit thick, the one i was getting was very thin. I tried rings of different Toyota engines. Toyota 4AF rings were bought.
On its box it was written 90x4mm.
When we dropped those rings in cylinder walls the Rings were slightly bigger so we had to trim them accordingly. And in the end the trimmed rings were adjusted with hair line gap between there cuts.
And then pistons were released in. I have not increased the bore size.

They were loss because qg18de is multi alloy engine pistons expands more than block at specfic temperatures you need to have good piston clearance in there so that piston doesn't seize

[dani_kk]

Yes it has a good clearance @saboor73.

[Mirza967]

which type of honing they used bottle brush or oil stone type?? it wud be really helpful if u show close view of hone pattern......m just asking out of curiosity not to degrade any1

[Xulfiqar]

so I believe you are gravely mistaken, if you bought a pack of rings for a toyota 4AF, they are 81mm bore - whatever package you bought was wrongly marked, or of something else completely. Piston rings are imported in Pakistan in shrink wrap by the thousand count, the little boxes, wax paper and blister pack are made locally in Pakistan.

If you filed down the std size 4AF 81mm rings to sit in an 80mm bore on an 80mm OE piston - this is nothing new, its called jugaar ka ring and it never lasts as the rings never sit completely round in the cylinder, you actually damage the cylinder while this is running. There were lots of people trying this on almost all engines in Pakistan just to save money because for them "a revolving engine is a good engine" Ring gaps, ring/land clearance is not considered - infact most desi mechanics assume rings seal compression from their own tension and a polished like glass cylinder surface.

Rings for such engines are available but you have to purchase them from outside Pakistan as these engines were not sold in Pakistan in any car, same for gasket and rebuild set. I know they cost more because of duty and shipping charges but its a given cost when you buy a scrapped JDM engine.

Not belittling here, but consider what you just did for yourself -- This is a public forum whose posts are searchable by google, imagine the "kwaltee" of your service being showcased here where you are shoving larger rings into smaller bores.

If you dont believe that the google comment is true then look up toyota K410 CVT unit refill procedure, it probably is the most targeted page on PW - many people have landed on it from many different countries.

btw - that "hair thin" gap on rings is called ring gap and is a carefully measured clearance which is specced in the service manual, so is the land to ring clearance.

the ring gap on a QG18 are

C1 - 0.20 - 0.38mm l=0.49mm
C2 - 0.32 - 0.56mm l=0.65mm
Oil - 0.20 - 0.69mm l=1.09mm

the land/ring clearance is

C1 - 0.045-0.080mm l=0.2mm
C2 - 0.030-0.070mm l=0.2mm
Oil - 0.065-0.135mm l=0.2mm

You wont be getting these numbers with 4AF rings in a QG18

[SER_GTR]

so I believe you are gravely mistaken, if you bought a pack of rings for a toyota 4AF, they are 81mm bore - whatever package you bought was wrongly marked, or of something else completely. Piston rings are imported in Pakistan in shrink wrap by the thousand count, the little boxes, wax paper and blister pack are made locally in Pakistan.

If you filed down the std size 4AF 81mm rings to sit in an 80mm bore on an 80mm OE piston - this is nothing new, its called jugaar ka ring and it never lasts as the rings never sit completely round in the cylinder, you actually damage the cylinder while this is running. There were lots of people trying this on almost all engines in Pakistan just to save money because for them "a revolving engine is a good engine" Ring gaps, ring/land clearance is not considered - infact most desi mechanics assume rings seal compression from their own tension and a polished like glass cylinder surface.

Rings for such engines are available but you have to purchase them from outside Pakistan as these engines were not sold in Pakistan in any car, same for gasket and rebuild set. I know they cost more because of duty and shipping charges but its a given cost when you buy a scrapped JDM engine.

Not belittling here, but consider what you just did for yourself -- This is a public forum whose posts are searchable by google, imagine the "kwaltee" of your service being showcased here where you are shoving larger rings into smaller bores.

If you dont believe that the google comment is true then look up toyota K410 CVT unit refill procedure, it probably is the most targeted page on PW - many people have landed on it from many different countries.

btw - that "hair thin" gap on rings is called ring gap and is a carefully measured clearance which is specced in the service manual, so is the land to ring clearance.

the ring gap on a QG18 are

C1 - 0.20 - 0.38mm l=0.49mm
C2 - 0.32 - 0.56mm l=0.65mm
Oil - 0.20 - 0.69mm l=1.09mm

the land/ring clearance is

C1 - 0.045-0.080mm l=0.2mm
C2 - 0.030-0.070mm l=0.2mm
Oil - 0.065-0.135mm l=0.2mm

You wont be getting these numbers with 4AF rings in a QG18

Maybe We Just Find Out Business Secret This Is It

[ahmed2396]

Toyota 4AF bore is 81mm and QG18 bore is 80mm i don't understand where you got 90mm Toyota 4AF rings and made it 87mm and you say its stock QG18 bore then this is 7mm overbore, stock is 80mm bore. And even if you fit 81mm on 80mm it will fail, many mechanics do this and in the end they are replacing their engines. And QG18 head bolts are TTY they are to be replaced when they're stretched.

[ahmed2396]

I have once done Head Gasket replacement on QG18, i ordered Fel-Pro Head Gasket set with Fel-Pro Head Bolts, these both costed me $90. And car was good to go, early QG18 had some issue of head gaskets so had to do it.