E30 head improvements

[2fast2Z]

To avoid jacking another topic, i start this one, i like to get advice about what to do to a E30 head for improvements.

 

TonyD, the reason for me to ask, is that i have a similar E30 head as the one Ray have and i'm planning on using it on my L28 build, i asked because i remember Ozconnection previously have made some comments to E30 heads, the ports are pretty small (28 m.m. IIRC)and i don't want to open them up to much, chambers and valves are also small, i have a E88 valve train i'm planning to use and i believe that i have to open the chambers up a little because i want to be able to run on 95 pump gas, maybe unschrouting will be enough, so any advise will be appreciated.

 

Chris

[Tony D]

Putting in larger valves without the corresponding intake runner diameter increase? That seems like a lot of work to just strangle it. The combustion chambers are going to be what? Maybe 40CC's? On a 458CC bore? 11.45:1 compression...

 

I think bigger valves cutting the chamber larger will knock that down minimally, but that's pretty high for RON gas... 95 R+M/2 might fly in the heat, but RON only may be a tad pingy...

[2fast2Z]

WOW that was fast Tony, don't you sleep over there.

 

This is exactly why i like some comments, i do want to open up those ports, to 32-35 m.m., just don't want to open them up so much as i see in other topics floating around here, my aim is to get a engine with a good low end performance, the other head option i have is to use a E88 i have.

 

The rest of what you wrote, i didn't really understand, English is not my native you see.

 

So Tony, what would you recommend me to do with that head ?

 

Chris

[Tony D]

WOW that was fast Tony, don't you sleep over there.

 

It's 0115 at 'home' in SoCal. But I'm not there....

 

I'm in Seoul Korea... where it's 1815.

 

And being in Denmark you're only a half a day behind me...

 

If you have an E88 Head, I'd likely use that. It's dependent on if it's an L24 E88, or the L26 E-88. Some differentiation of the combustion chambers.

 

Unless you are willing to spend the time to make the chambers you want by hand...the E30 will be a lot of work.

 

For someone making a full on race head, an E30 may result in some more 'labor' time for hogging out ports, compared to an E88 or N42 head... but you won't be welding on the combustion chamber, and since you're changing to big valves in that case anyway it ends up being a net savings using that head. Plus, no welding warpage to worry about!

[2fast2Z]

Korea, that explains it.

 

I have no idea of what kind of E88 it is i have, maybe Ray know, i got it from him, it have open chambers.

 

I had the idea that this E30 would be a better head to use because of the "squelsh" area, i do not mind spending some time working on this head, but if benefit will be little to none, i can spend my time on other stuff.

What i wanted to achieve was, squelsh and high compression but still be able to use pump gas (95)

 

Chris

[ozconnection]

"What i wanted to achieve was, squelsh and high compression but still be able to use pump gas (95)"

 

Chris, this is something that I've been spending a lot of time researching.

 

I do still have that lovely Y70 head sitting in my garage, waiting for me to put it on.

 

The E30 head you have was also fitted to the L24S (single two barrel Hitatchi carb) spec. engine. It had 1.5 inch and 1.3 inch valves in it, and the ports were small at around 30 mm's. (The exhaust ports were square and not like the Y70 which has round with liners). So, that E30 head must flow reasonably well to bolt it straight onto the 2.4 litre engine by the factory without any immediately apparent modifications.

 

Bolt that E30 head to a stock 2.8 bottom end, like the N42 bottom end with factory spec dished pistons, the potential is there for a 9.9 to one compression engine with a stock bore Nissan factory HG.. To add to that, without porting ie making larger, the ports would have incredible gas speed for low speed torque with a stock or near stock engine.

 

The smaller valves were deemed to be an advantage (by me) over the stock L28 valves which are heavier. With some attention to this, a very high revving valvetrain could be achieved on the E30, coulped to a bigger cam profile to take advantage of this rev-ability, which was also deemed acceptable to bleed of some of the cylinder pressures at low rpm's which could have thrown the engine into detonation.

 

That's another reason I wanted to hold off with the Y70 instal. I wanted to see how much of a headroom above stock I could build into the cooling system, with coolants, fans, thermostats, radiator caps, radiators and water pumps all being tested. In conjunction, there've been changes to my spark plugs and engine oil ratings as well as some thermal wrap on the headers and heat shielding around the carburettor. I should, but haven't yet, improved on the air induction temps into the carby by ducting cool air straight into the carb.

 

From what I've gathered, you want this head for a street engine. Now you could build an engine like mine at the moment with the completely stock N42 head. (It pulls pretty bloody well with all the recent mods by the way!!). OR you could dive into modding the E30 and throwing that on. It's up to you.

 

With the E30, I wouldn't go crazy on the ports or valves otherwise just use the other head like your E88. The stock cam will give you an awesome low end but detonation could be a problem unless you're willing to chase that issue. A bigger cam will make much more power at the top end. I honestly believe it's the choice made here that will ultimately determine the way your engine performs. The camshaft will truely be the brain of the setup but several different grinds may need to be tested before the best one (for you) is found. Expensive!? Hmmmmm, not too bad if you want to work to develop this combination and just sell off any parts you know you won't need/use afer you're done. Just a thought.

 

Cheers.

[2fast2Z]

Hmmm, interesting, so you would not use bigger valves ?, i do have flat tops for that F54 block, so as i see it right now, is a compression issue, i will need to get that down, i know many here have heads with huge ports, using huge cams with very high lift and are running a hell of alot RPM's, that's not my goal as stated above and the logic about having smaller ports to make a venturi effect and speed up air flow is clear to me.

 

I think it could be a idea for me to start by measuring the CC that the stock champer have IIRC it is 39 and then go from there, removing a little material at a time and then see what CC i can come up with.

 

Chris

Edited February 27, 2010 by 2fast2Z

[Tony D]

"The smaller valves were deemed to be an advantage (by me) over the stock L28 valves which are heavier... With some attention to this, a very high revving valvetrain could be achieved on the E30, coulped to a bigger cam profile to take advantage of this rev-ability, which was also deemed acceptable to bleed of some of the cylinder pressures at low rpm's which could have thrown the engine into detonation."

 

Nik the idea that 'L20A Valves are Lighter and therefore will rev higher than heavier L28 Valves'

 

This L20A is running 'heavy' L28 sized valves, and our shiftpoints are WELL below what we have actually run the engine up to testing valvetrain stability. We have not floated or lost valvetrain stability yet on our engine... And we have stock, unlightened, un polished, generic nissan rockers on this engine as well... Don't overthink this stuff...

 

[ozconnection]

This L20A is running 'heavy' L28 sized valves, and our shiftpoints are WELL below what we have actually run the engine up to testing valvetrain stability. We have not floated or lost valvetrain stability yet on our engine... And we have stock, unlightened, un polished, generic nissan rockers on this engine as well... Don't overthink this stuff...

 

 

Isn't there a sticky that relates to all kinds of valvetrain mods....balancing the valvetrain? Worthwhile mebe?

 

Nothin' wrong with overthinking mate......it's the thinking part that's important. HeHe! (that's my therapy!!)

 

Cheers