Machining cylinder head for more compression?

[dutchzcarguy]

21 hours ago, z shredder said:

The thing about the E31 heads is that they are extremely hard to find in Germany

A friend of my has one restored to new for 1500 euro's and lives near NRW Germany..     I told him and he contacts you for it.

[bartsscooterservice]

Yes, I have an E31 if you want. It's ready to bolt on. It's not lying in my way though, was planning to use it as a spare part

 

[bartsscooterservice]

On 1/8/2021 at 5:48 PM, z shredder said:

Hello,

I am looking at buying an L26 engine for my 240z the plan is to use the l24 flat top pistons and a decked e88 cylinder head to get more compression.

The ozdat calculator says that with a 1.25mm thinner head gasket and the l24 pistons I will get a compression ratio of 10.5/1 is this equivelent to machining 1.25mm of the cylinder head and using the stock head gasket?

Is it even possible to remove that much material?

Endurotec +060 Pistons Set Of 6 suits Nissan L26 | eBay

You need at least change the piston's to higher quality ones, that raise your compression. A big cam and weber carb setup is a must if you want to have some power from it.

You could also lighten the flywheel and some good headers are needed.

Then offcourse the head.. 

[z shredder]

Thanks for the offer but I am not going to spent 1500€ on a cylinder head 😁

Do I really need new pistons? Until now I was planning on using L24 flattop pistons.

[Zed Head]

On 1/9/2021 at 6:22 AM, z shredder said:

Well I have 2 options using the E88 head from the l26 or using the E88 head from my l24 I heard that the l26 had bigger valves and that's why I wanted to go with this. 

You're getting a lot of advice about the fine details to get that last 10-15% of power from an engine.  It looks like you are starting with an L24 and have the option of buying another L26.  Both factory stock engines, maybe?.  It will help you to define what you want the engine to do when you're done.  You can spend a lot of money on parts that won't help you reach your goals.  Plus the money you can spend removing or modifying perfectly good parts to install the unnecessary parts might be wasted.

The parts all need to work together.  Expensive pistons that never see more than 6000 RPM are probably a waste.  High CR with poor fuel is a waste.  A ported head with a poor exhaust system is a waste.

You started your thread with machining a head, but machining a head should be in the middle of your list of things you need to do to reach your goals.  You need a plan first.  Plus you need to know the quality of the parts you're starting with.  If the L26 has already been bored you won't be able to use your L24 pistons in it, for example.  But you might be able to use the L26 crank in the L24 block.  Example.   Since you're limited in finding parts and spending money, many of the suggestions made won't be reasonable for you.

I'd get the parts and see what's usable.  You might find cracked heads, trashed cylinders, damaged valves, etc.  Don't spend too much money until you know what you have in front of you.

[bartsscooterservice]

He lives in Germany, they have high octane fuel

[Jeff G 78]

5 hours ago, bartsscooterservice said:

He lives in Germany, they have high octane fuel

Not really.  They have 98 RON which is the same as 93 pump octane in the US.  The US uses (RON + MON) / 2 method.

[bartsscooterservice]

20 minutes ago, Jeff G 78 said:

Not really.  They have 98 RON which is the same as 93 pump octane in the US.  The US uses (RON + MON) / 2 method.

There is also 100 and 102 RON

[z shredder]

Here in Germany we can get 100 octane fuel at most gas stations, yes octane not RON!

[madkaw]

So was there Nissan sedans in Germany ? Are they in JY’s there ? Is or was there a variant of the Maxima for that era ? That would be the head to get

[dutchzcarguy]

On 1/10/2021 at 6:19 PM, z shredder said:

Do I really need new pistons? Until now I was planning on using L24 flattop pistons.

You have a 1973 240z engine L24?  YOu know that these engines have flattop pistons that just come above the deck of the block? there was a service newsbulletin telling that these heads of a 1973 are different so watch out..

Btw..  Your a student?  (I have never seen a student with the money for a restauration of such a car) .. have you thaught this through?  Don't think "ow it's easy" ..     

There is a firm here in the Netherlands .. it sells 240z wrecks!!! for 10-15000 euro.. and about EVERY part needs to be repaired or renewed.. There are a lot of people that look through a pair of pink glasses at their cars but don't realise that these resto's cost a LOT of money. (I hope yours is not as bad..)

≥ Datsun 240Z (bj 1971) - Oldtimers - Marktplaats.nl

I always tell people if you want a good reliable car you have to invest the money for a new car..  otherwise you will have a lot of brakedowns and exasperation. (irritation to the MAX!)

[z shredder]

7 hours ago, dutchzcarguy said:

You have a 1973 240z engine L24?  YOu know that these engines have flattop pistons that just come above the deck of the block? there was a service newsbulletin telling that these heads of a 1973 are different so watch out..

Btw..  Your a student?  (I have never seen a student with the money for a restauration of such a car) .. have you thaught this through?  Don't think "ow it's easy" ..     

There is a firm here in the Netherlands .. it sells 240z wrecks!!! for 10-15000 euro.. and about EVERY part needs to be repaired or renewed.. There are a lot of people that look through a pair of pink glasses at their cars but don't realise that these resto's cost a LOT of money. (I hope yours is not as bad..)

≥ Datsun 240Z (bj 1971) - Oldtimers - Marktplaats.nl

I always tell people if you want a good reliable car you have to invest the money for a new car..  otherwise you will have a lot of brakedowns and exasperation. (irritation to the MAX!)

This reminds me a bit of this cartoon I used to watch as a kid called phineas and ferb were they would build crazy stuff and everybody asked "aren't you to jung to build (insert something crazy)?"

and they would just reply with "yes..... yes we are" and continue building.

As a Kid I never really spend much money on anything since the age of 5 to save up to someday buy a cool car. I also got some finencial help from my parents because they didnt want me to ride a motorcycle.

And about the car yes it WAS really bad, lots of rust, bad suspension all around, bad wiring and so on......

Right now all of the structural rust has ben fixed the car has a complete new floor pan welded in by welder/chassis builder for free by trading him spare porsche 914 parts 😀 I can weld so I will repair the rest of the rust myself.

I removed all of the suspension (A-arms, Struts, sway bar, steering, brakes) even the differential and tank everything got new bushings and all off the surface rust painstakingly removed so that I could paint all of it, while at It the underbody also got painted/undercoated.

Aswell as the new bushings I also installed kyb gas struts because the old ones were not good. I also removed all of the rubber seals, all of the glass, all bodypanels, interior to restore.

The dash was cracked so i used filler and lots of sanding to repair it all of the gauge glasses were so crappy that you couldn't see the gauges I removet them and polished until they were clear again.

So I basically tore down the car to the bare chassis in a small garage with no lift so working with a jack and jack stands.

"have you thaught this through?" well I think I am doing pretty ell for a 16 year old with a limided budget. This is no half a$$ed restoration! I already have all of the restored suspension, brakes, steering and differential installed, the car is getting ready for paint and

removing the engine block (cylinder head and everything else is already removed).

A restoration doesent have to be horrendously expensive if you do all of the work yourself and spend your money smart!

I will upload a few pictures of the car so that you get an idea.

Edited January 12, 2021 by z shredder