Engine temperature tests and results

[BRAAP]

Ok, pictures taken, received permission from the owner of the N-42 block, (thank you Mark) The custom Clark copper head gasket is for custom road race N-42 block, N-42 head combo. The Clark copper gasket mimics the early ’75-’80 Felpro gasket exactly in regards to coolant ports.

 

I also rounded up a scrap N47 head and a scrap P90 head so we have an early block, early FelPro head gasket and early head as well as a late block, late Felpro head gasket, and late head.

 

I really have no opinion as to which would work better under what conditions as the amount of ports, size of the ports and locations don’t seem to follow any sort of pattern other than there is a large port at the back of the block/head to help flow coolant form the front of block to the back, then up into the head and through the head to the front, thermostat housing. Early gasket, Felpro part number 21157PT-1 for the '75-'80 L-28 and Felpro part number 8799PT for the '81-'83 L28E & L28ET.

 

First pic is of the 2 different FelPro head gaskets. Main differences are that the early Felpro gasket allows coolant flow on the spark plug side of the head where as the later gasket doesn’t, and Nissan changed the areas on the manifold side of the head/block where coolant transfers from the block to the head, (gaskets match the ports in the heads here). Next pic is of the heads and the heads with their matching gaskets. Below that are the blocks, blocks with their matching gaskets, then blocks wearing non matching gasket…

 

Gaskets;

 

Heads;

 

Heads w/gaskets;

 

 

 

Blocks;

 

 

 

 

N42 Block wearing both gaskets;

 

 

 

 

F54 block wearing both gaskets;

 

Edited January 10, 2010 by BRAAP

[ozconnection]

Fantastic stuff Paul! Great photos.

 

Now what do we do?

[woldson]

Just a 2ct.

 

Seems like they dedicated more flow toward the intake and exhaust side, or at least increased pressure in the later years. (hence the lack of passages on the spark plug side).

 

Great pics!

[Tony D]

JeffP has Photos, but I'm thinking at this point 'not for public consumption' just yet...

[sticky280zx]

Need more info on this stuff guys, stop hoarding all of your secrets and let us all know how to run some big advance numbers on stock motors =) you guys can keep the full race stuff.

 

I second the sticky motion...along with the other thread that Braap has alot of info in on the same subject...maybe combine the two?

[ktm]

We supplement our fuel (methanol injection, water injection - myself, big-phil), run ethanol (510six, Timz), or run higher octane fuel.

 

I've done the cooling modification described in the sticky near the top of this forum and it has helped considerably with evening out the heat distribution in the head. This will allow you to run more timing but not considerably more.

 

Keep in mind that producing power is not about "big advance numbers", but rather running enough timing to get the peak cylinder pressure to occur around 15* ATDC at mean best torque.

[NewZed]

With ethanol you run more advance?

 

I have been Googling around trying to figure out what Oregon's E10 10% ethanol fuel mix does to an engine's timing requirements, and find that many people blame all of their engine problems on ethanol in the gas, from bad mileage to detonation to slow destruction. I haven't found a good discussion on how to tune for it's use.

 

I have a stock motor, 1976 with EFI, that runs well but seemed a little down on power and gas mileage. I added 3 degrees initial advance (working my way up to more extensive {low budget} modifications, but I need to understand how these motors work first) and it seems to run better - smoother, more responsive and quicker. But I worry about the detonation that I've read about on this site and others, especially once the hot summer gets here.

 

Any insights on using ethanol/gasoline blends would be appreciated.

 

Thanks.

[Ben]

E10 could cause in increase in pre-ignition, if the EMS is not able to cater for the increased fuelling requirements, and you were already running a little lean on Gasoline etc.

As for destructive detonation - I highly doubt that E10 would cause a perfect motor to grenade without some other significant contributing factors.

You can potentially squeeze a few more HP out of an 'E' blend, as it tends to be rated at a higher octane. There are a few brands of 98RON PULP available here in South Australia that have an Ethanol content (but not as high as 10%), and I'm fairly confident that I get nicer running from my RB25DET with this fuel than plain-Jane 98RON (rated) Gasoline. The economy suffers a little, but she's a happier engine on the whole.

 

Pure methanol is a different story (~6:1 AFR's, corrosive, and more power - potentially), and I'd only ever run water injection - but that's a climate issue. It never gets cold enough here to warrant the anti-freeze attributes that the tiny % of Methanol brings to the water/meth blend. And that's what the Meth is there for; not more power, but anti-freeze.

 

Solving the detonation problem is best attacked form many angles - charge cooling, sane boost, good mixtures, sensible timing, spot-boiling control (which thanks to this thread I have learnt a lot more about), and anti-detonants (choose your poison!).

[garvice]

Any insights on using ethanol/gasoline blends would be appreciated.

http://www.ozgarage.com.au/page/2

Episode 10 - They talk a lot about the benefits/power gains from ethanol, but they don't say too much about the fact that they are using a lot more fuel to make that power (ran out of injector when running E85).

[NewZed]

Thanks for the ozgarage link. I did not know that was out there. Fairly informative, although, as you say, the main lesson seems to be that more ethanol in the fuel means you need more fuel in the engine. The E10 was estimated at 95 octane so it's not clear how much of the timing adjustment is from ethanol and how much is from octane number.

 

I was hoping someone had actually noticed and recorded performance and tuning differences between 91 E10 and 91 E0, on a somewhat close to stock engine. Maybe there is none, except for slightly poorer mileage.

 

Thanks again for the information.

[TimZ]

Thanks for the ozgarage link. I did not know that was out there. Fairly informative, although, as you say, the main lesson seems to be that more ethanol in the fuel means you need more fuel in the engine. The E10 was estimated at 95 octane so it's not clear how much of the timing adjustment is from ethanol and how much is from octane number.

 

I was hoping someone had actually noticed and recorded performance and tuning differences between 91 E10 and 91 E0, on a somewhat close to stock engine. Maybe there is none, except for slightly poorer mileage.

 

Thanks again for the information.

 

You can also look here:

http://e85vehicles.com/e85/index.php

http://e85forum.com

 

...but to answer your question, the difference in AFRs for stoichometric mixtures for E10 vs E0 is ~14.1 vs 14.7 AFR, or about a 4% increase in fueling for E10. Not a huge difference, and if anybody is destroying their engine by using E10 instead of E0 they had a pretty p*ss poor tune to begin with.

 

Timing requirements are a little different at higher ethanol percentages, but for the most part you can use the exact same timing as you use for E0, even with E85. The main thing that you might notice is that you may be able to run a bit more timing if you were artificially backing the timing off to avoid knock with E0, due to E10's higher octane.

[ktm]

Pure methanol is a different story (~6:1 AFR's, corrosive, and more power - potentially), and I'd only ever run water injection - but that's a climate issue. It never gets cold enough here to warrant the anti-freeze attributes that the tiny % of Methanol brings to the water/meth blend. And that's what the Meth is there for; not more power, but anti-freeze.

 

You best do some more research. Methanol is not used simply for anti-freeze properties. It may be used as such in window washer fluid, but as an injectant it is used for intake charge cooling and fuel supplement. The corrosive issue is minor when injecting. I am injecting 1400 cc/min of methanol and replacing 25% of my primary fuel with methanol. 510six used to run meth injection and Bernard and big-phil use it extensively as well. The Buick GN crowd swears by it (www.turbobuick.com) as do many of the RX7 folks (www.clubrx7.com). Subies and Evos are into heavily as well (www.nasioc.com and www.evolutionm.net).

 

I am not going to go into a long discussion regarding methnaol injection. There is a plethora of information on the web regarding methanol injection.

[Daeron]

Wow, I have somehow completely missed this one so far.. Must follow closely!!

 

Braap: I doubt I will find the time to do it, but might I have your permission to alter the above photos indicating coolant vs oil passages and whatnot?? It may show my lack of experience in building, but I still have no idea which holes is which yet and if I can get all that info I'd be happy to do the legwork myself to make those pictures a little more data-rich at a glance for those who like me, are not yet quite on such intimate terms with the holes in our engines

[Ben]

You best do some more research....

 

I shall do just that. Like I have said in other threads; I'm interested in using Water Injection with my application, but haven't done so as yet and defer to those in the know!

[BRAAP]

...

Braap: I doubt I will find the time to do it, but might I have your permission to alter the above photos indicating coolant vs oil passages and whatnot?? ...

 

Permission granted.

 

I'd like to see some more discussion on this..

[ozconnection]

The discussion on different/alternate fuels is interesting yet somewhat out of reach for the 'average' motorist it would seem. It would be a no brainer for any form of competition where these fuels are allowed, and expected.

 

For the ordinary guy who fills up at the local gas station all this talk of special fuels is somewhat ott in my opinion. The point I'm making, there are some limits to the extent people will go in the search for better performance, and IIRC, I wanted to see 40 degrees total advance on a relatively stock engine (N42/N42) combination with ordinary gas station fuel. This is what Paul said I 'should' be able to achieve, and I've been giving it a good hard go (thermostats, water pumps, spark plugs, air/fuel mixtures, ignition timing and so on).

 

I have been noticing that there are distinct performance variances depending on the weather (not just seasonally but daily!!). I consulted my bible and it seems this is true, that a "7-10% increase in the relative air density (RAD) could result in an air/fuel mixture lean enough to produce a set of melted pistons, if you don't richen the mixture accordingly. Also a decrease in the relative humidity could see the engine detonating unless the spark advance, or the amount of cam advance, is reduced." Unfortunately, it's not mentioned what the compression ratio or the state of tune of the engine is. However, the trend is there, and I'm the first to back that statement up with my recent testing and results. (Thank god I haven't holed a piston or anything, but we all know that L's are pretty tough and take a fair amount of punishment, usually!)

 

The interesting point mentioned here is camshaft timing. I've not heard of people changing their cam timing anywhere near as often as their ignition timing to suit the ambient conditions. I could understand changing the ignition timing seasonally due to wide temperature variances, combined with the additives used in fuels as the seasons change, but cam timing? Who does that? It's a tuning variable sure, so should we (I) be looking at this too Paul? (I must point out that my stock cam is heavily advanced atm for the low speed torque it provides me with). Would there be optimum advance curves for each change in camshaft advance?....now that's interesting. All this stuff reminds me of the Vtec setups and how the Honda et al engineers must've considered all this stuff and built something that could do it.....all.

 

Buggar!

[Zmanco]

Interesting comments about changing cam timing. This weekend I experimented with delaying the cam 3 degrees and found I was able to run several more degrees of ignition advance from 4k on up. I did not have the time or opportunity to do any controlled testing so the exact number is probably meaningless, but I did add 3 degrees and did NOT hear any audible detonation. The last time I experimented with timing, that much more timing WOULD have caused audible detonation. However, the temps were a little cooler, so I'm not convinced this will still be a safe tune when it warms up again.

 

Engine is an L28et block, shaved P90 head (8.3 CR) with cyl 5/6 cooling mod, Schneider stage II turbo cam, T3/T4OE limited to 8 psi for now.

[letitsnow]

Interesting comments about changing cam timing. This weekend I experimented with delaying the cam 3 degrees and found I was able to run several more degrees of ignition advance from 4k on up. I did not have the time or opportunity to do any controlled testing so the exact number is probably meaningless, but I did add 3 degrees and did NOT hear any audible detonation. The last time I experimented with timing, that much more timing WOULD have caused audible detonation. However, the temps were a little cooler, so I'm not convinced this will still be a safe tune when it warms up again.

 

Engine is an L28et block, shaved P90 head (8.3 CR) with cyl 5/6 cooling mod, Schneider stage II turbo cam, T3/T4OE limited to 8 psi for now.

Was it faster? You're getting into places where adding advance might not add any more power. Remember, the point of ignition advance is to make the pressure peak occur at ~15 ATDC.

[Zmanco]

Was it faster? You're getting into places where adding advance might not add any more power. Remember, the point of ignition advance is to make the pressure peak occur at ~15 ATDC.

My goal with the cam change was to smooth out the torque curve and move the peak up a little higher - not necessarily gain more power. In the process of retuning with MS I found a mistake in a configuration and decided to add a little more advance. My observations are all seat of the pants and the net was a little less torque below about 3500 rpm in exchange for less fall off in torque between 5.5 and 7k rpm. But if I had to guess, and based on previous experiments with cam timing, most/all of that difference was due to the cam change, not the timing change.

 

I don't want to hijack this thread, just thought it was interesting that I was able to add more advance after a small change to the cam timing. One more variable for us to tweak...

[ozconnection]

 

I don't want to hijack this thread, just thought it was interesting that I was able to add more advance after a small change to the cam timing. One more variable for us to tweak...

 

Nah Daniel, you're not hijacking this at all. You're comments are exactly what I'm looking for.

 

Over the weekend, I might pull back the cam timing a bit so I can test out the ignition timing, with a degree or two more advance, see what happens.