thinking 16v astron head

[barana]

So I'm thinking ... how do i get my 4g54 that im building to breath more - not in extreme ways, I want to get more air in there, but in a reliable cheap way from low revs to high - no i dont want a 30/70 cam in it!
so im remembering that some speed shop in .au was developing a dohc head before mitz .au canned the magna 4G54...
i have a 4d55 here in another l300, its the yard van it does all the gardening work with me.

4D55, 4d55 - they made a 4D56 too - wiki says its still used in modern applications - me googles further.. common rail injection with variable geometry turbo , me googles and..... theres a DOHC version!!!

as long as they havent modded the astron too much, and the timing cover can be retro fitted, i recon the 4D56 dohc head would be a decent way to get the the 4G54 to breathe.
and yes, I'd have to remachine the glow plug holes so spark plugs would fit - thats ofcourse if common rail needs glow plugs anymore - like 3L+ diesels.
Has anyone else had these thoughts, or even tried it out?
-Barana.

[scully]

Unfortunately the diesel head will not work on the 4g54 petrol engine. One reason is that a diesel engine runs a very high static compression ratio, and the cylinder head does not have a combustion chamber in it, the face of the head is flat and the valves are vertical. The combustion chamber is a small bowl in the piston. Also, while the 2.5 common rail diesel used in the Challenger/Triton is distantly based on the 4d56, I would think ( but I don't know for sure) it would have changes to the number & size of head bolts used to contain the huge combustion pressures these engines develop.

A 16v 4g64/69 may be the easier way to have a large capacity mitsu 4cyl

[cheaterparts]

So I'm thinking ... how do i get my 4g54 that im building to breath more - not in extreme ways, I want to get more air in there, but in a reliable cheap way from low revs to high - no i dont want a 30/70 cam in it!
-Barana.

what is extreme and what isn't in your book

first what head are you running there is plenty of info on this site on how to make a 4g54 perform

first find an M6 or M7 magna head casting - these have the highest flow of any off the shelf head, fit a set of 1 mm OS stainless valves
they cut straight into the std valve seats so is not to pricey to have done

if you wont it to breath you will need to change the cam and I wouldn't use a 30/70 ether its no where big enough I use a cam that is 45/85

and then you will need to do something about your induction at least a set of 45 mm webers as a min 48s or 50s would be better

so just so you know that an astron 8 valve can breath ok I have spun the engine to over 7k in 4th gear with a 3.89 diff at sandown raceway
and still had enough bottom end to pull out of dandenong corner in 3rd

[barana]

I will be towing a yaght So i will need heaps of low down grunt for that purpose, and driving a high roof 4wd l300 on the highway - this machine is a crosswind magnet the slightest wind pushes it around on the highway - so i need grunt midrange and high up too, as well as decent economy etc etc i think a 4 value head may give wider breathing that a 2 valve cant. It also will open the door up to adapting vvt to the astron ;-D

[barana]

now this is what im getting at.
I really have to admire the engineering.

[geezer101]

If you want a 16v engine it won't be an Astron. Your best bet will be the 4G63 which is an older 2L twin cam or the 4G64 which is the recent 2.4L twin cam. The '64 is on the expensive side but has pretty good power in stock form.

[barana]

well the diesel astron is belt driven -thats going to be a bitch to try and convert to chain drive - and the head is flush with no combustion chamber in it (like some astron and sirrus heads ive seen)
I recon the logical conclusion is - get hold of a 4d56 DOHC and petrol-ise it.It would be do-able think about it - this diesel engine has a 16.5-17:1 CR - which is a function of the crank, so i swap in the steel 4g54 crank i have, next if with that crank the CR is still to high i can use astron 1 dished pistons, next the block can handle 400NM of torque plenty of bottom end strength for a petrol, next its belt driven - sure i prefer a chain, but belts are quieter, next with belt driven cams, i can adapt a vvt setup. I'm guessing the price would be high might be the same as adapting a 4g64.

[barana]

EVERYONE does the average, the mundane - a 4g64 swap is just too easy, My motivation is about doing the different, in a normal way. hence a dohc astron utilising factory bits.eg. If i do up a car, its a sleeper

Ill still do up my m6 headed efi astron and put it in the van, but i think ill have a stage ii and stage ii will be this idea!

[Billsy]

keep us posted on how you go sounds interesting, but why not just turbo the 2.6?
given the design principals of a diesel it wont run as well as you think on petrol.

will give you way more torque and power than any form of NA youll fit there. and be far more cost effective.

[webby]

First off, there's no way in hell I'd be towing a yacht with an L300. That's in big American-style pickup territory, or at the very least you'd want a turbodiesel Patrol/Landcruiser. The L300 just doesn't have the tare weight to tow something that heavy safely, and frankly, I think you'd be silly to try. You already mentioned how much crosswinds affect the thing, why add a bloody great boat hanging off the back of it to cause even more problems?

Second, even if you could get your idea to work, a basic turbo 2.6 would easily outperform it, tow quite well to boot, and it'd do it for a fraction of the cost. Being different's all well and good, but most of the time doing what's been proven to work and work well is the best way to go.

I can't see this working at all, but it's your money to burn. Good luck

[amgis_obrut]

l300+commodore 3.8 = tow van of death

[barana]

800kg to 1000kg is within the rated towing capacity/towbar capacity - the expected weight range of my trailer sailer

Turbo's increase the insurance premiums besides im a N/A type of guy.

if it wasnt for the higher rego costs for a 6cyl, i would have slotted in a mitz 3.0L v6 - much better.

using a 2.6 petrol crank in the 4g56dohc will decrease the compression ratio to something resembling the 4g54, with the added bonus of 4 valve head and an external oil pump. -

I made an enquiry to the wreckers network, a dohc 4d56 d-id in a triton with low klm will set me back 2800 currently.which isnt that bad, it will make a good phase II project after the magna 4g54 conversion.

on a side note, I got a hold of a 2.6 pajero sump for my magna l300 conversion. it seems the bottom of the block at least and the sump on a early 4g54 that goes into a pajero are quite a bit different - way larger than the magna block. might just have to take a sledgey to the magna sump come fitting time ( to clear the diff centre)

[barana]

Billsey: is there any diesel principles apart from compression that you have in mind ?

[geezer101]

...and the ignition system? It'll need a crank angle sensor to give it spark - the diesel head hasn't got an allowance for a distributor install. The magna injection isn't going to mate up to the diesel head no matter what you do to it and will it take some ferocious engineering work to seal the front of the head with a timing case and convert the cams to chain sprockets. You really want a twin cam 16V head that badly? You will need the holy grail of Astron 2.6 heads - the super-low production performance head made by HKS. Rumoured to have only made about 16 of them...

[barana]

well the diesel astron is belt driven -thats going to be a bitch to try and convert to chain drive - and the head is flush with no combustion chamber in it (like some astron and sirrus heads ive seen)
I recon the logical conclusion is - get hold of a 4d56 DOHC and petrol-ise it

I wont try to convert belt drive to chain drive, becuase ill retain the belt driven very different astron block along with the head

i should have said 'get a hold of an entire 4D56 DOHC engine and petrolise it' for clarity's sake, sorry fellas.

the injector holes can be drilled into the lower part of the j shaped intake ports on the head. the diesel throttle body - (arent some common rail injected diesels made without throttle plates?) can be replaced with a magna/commodore one.

i wont bother with a wasteful crankangle sensor/distributor type of setup from the magna - rotors are so ineffcient.I will use a delco efi setup from a vx onwards commodore. delcohacking.net show u how to modify and tune these to other engines. with an external pulley/belhousing mounted crank angle sensor.

[scully]

well the diesel astron is belt driven -thats going to be a bitch to try and convert to chain drive - and the head is flush with no combustion chamber in it (like some astron and sirrus heads ive seen)
I recon the logical conclusion is - get hold of a 4d56 DOHC and petrol-ise it

I wont try to convert belt drive to chain drive, becuase ill retain the belt driven very different astron block along with the head

i should have said 'get a hold of an entire 4D56 DOHC engine and petrolise it' for clarity's sake, sorry fellas.

the injector holes can be drilled into the lower part of the j shaped intake ports on the head. the diesel throttle body - (arent some common rail injected diesels made without throttle plates?) can be replaced with a magna/commodore one.

i wont bother with a wasteful crankangle sensor/distributor type of setup from the magna - rotors are so ineffcient.I will use a delco efi setup from a vx onwards commodore. delcohacking.net show u how to modify and tune these to other engines. with an external pulley/belhousing mounted crank angle sensor.

Converting a diesel to petrol would be easier to do than converting a 4g54 to 16v.

BUT there is some things that come to mind that would need to be changed:
Custom pistons to get the compression ratio correct. Would need a fair sized bowl to compensate for the flat head face. No astron petrol had a flat faced head.
Camshafts would need to be reground or more than likely new ones made to tie in with a petrol engine's rev range. The 4D56 DOHC peaks around 4000rpm whereas you would want to rev to 6500+ to be worth the effort on petrol. Valve springs would also need to be changed.
Conrods and crankshaft and flywheel are all designed to work within the diesel engine's rev range and would need to be lightened/modified

Are you sure that the 4v head is going to flow that much better than one off a ts magna? Remember the dohc head was designed to be used with a turbo and on a diesel, and may not flow well as a n/a. A 2v head can be made to flow almost as good as a 4v.
Even if you could overcome all the problems you will encounter, I seriously doubt you would end up with more power than a well developed 4g54.

I'm not trying to knock your idea down, just trying to be realistic. Anything can be done with enough time and money but this is going to take an incredible amount of work for possibly very little gain.

[rx22nv]

Seems like a lot of hard work and lots of cash for something that may not work. WHy not put the whole diesel turbo motor in?

I know you want to stick to NA, but a turbo would add so much more torque and make for a better tow rig.

Or standard motor, flat top pistons and more comp, magna head with injection. Keep the standard magna cam, it was designed to make torque down low. Bigger cam will move your torque curve up and be useless for towing.

Cool idea though but I think too many things to go wrong.

[Billsy]

Billsey: is there any diesel principles apart from compression that you have in mind ?

the valve sizing
port design
valve angle
valve springs likely not up to higher rpm

all likely optimised for a slow burning fuel, and not neccessarily designed for good swirl or a single point ignition source
also looks like a flat head, which isnt that flash.

im not an expert in this, but have read enough on engine design to know that you wont get a high performance petrol motor, by modifying a diesel.

[RaptorReed]

im not an expert in this, but have read enough on engine design to know that you wont get a high performance petrol motor, by modifying a diesel.

Ironically, GM did something like this in the late 70s with the 5.7l 350 V8, they modified the motor to be a diesel..resulted in piss poor performance and proved to be horribly unreliable.

[85hightop]

...and the ignition system? It'll need a crank angle sensor to give it spark - the diesel head hasn't got an allowance for a distributor install. The magna injection isn't going to mate up to the diesel head no matter what you do to it and will it take some ferocious engineering work to seal the front of the head with a timing case and convert the cams to chain sprockets. You really want a twin cam 16V head that badly? You will need the holy grail of Astron 2.6 heads - the super-low production performance head made by HKS. Rumoured to have only made about 16 of them...

A close family friend of mine used to run a 2.6 turbo powered lancer back in the 80ies, he was a Mitsubishi tech at the time and wrote the book on servicing the turbo sigmas, I was chatting with him last night about this and he took me up into his roof, opened up a wooden box and bam, all wrapped in plastic is a HKS twin cam head, it's a thing of beauty, he then promptly told me I couldn't have it : (

[75wagon]

I was chatting with him last night about this and he took me up into his roof, opened up a wooden box and bam, all wrapped in plastic is a HKS twin cam head, it's a thing of beauty, he then promptly told me I couldn't have it : (

Any chance of a pic of it?

[85hightop]

Yeah man, I'll try go see him on the weekend

[mic_77]

If he won't part with it what are the chances of borrowing it so a it can be copied in a billet once the program is done iris easy to pump them out.


Cheers Mic

[A112H]

Good point Mick.
At the very least grab some pics for us weirdo's to drool over.

[85hightop]

Haha yeah I've already rang a few places the are talking 10-12k each to copy it, hopefully pics up this weekend

[mic_77]

It can be done a lot cheaper than that does he have the complete conversion or just the head.

Cheers Mic

[85hightop]

What do you mean by the rest of the kit? Cams valves?

[mic_77]

Tapper cover, timing cover, cams, timing chain I believe that is the differences someone on here might have more info on these set-ups.

Cheers Mic

[A112H]

This come up every few years and this is as far as it ever goes.
From the old site 2009
http://www.sigma-galant.com/archive/mod ... 8&start=15

From the old site 2007
http://www.sigma-galant.com/archive/mod ... pic&t=4672

[yno26galant]

and where does this hks twin cam head live