Engine temperature tests and results

[ozconnection]

I thought I should start a new thread. At this point I don't want to be dumping my information onto someone elses thread.

 

I recently received my new laser heat gun. What an awesome little tool! I haven't been able to put it down since I got it. Seems like customs needed to look at it too...the box was resealed by the time I got it delivered. I purchased it from the States because our dollar is doing pretty well on the international money market and buying things from ebay is very often cheaper than buying it locally, even after the postage is included!!

 

So, with the 190 degree F. thermostat in the engine at the moment, here are some temps at idle after a drive around the block to warm everything up properly.

 

The cylinder head was measured net to the spark plug boss, about 1/2 inch to the firewall side of each one.

 

cyl 1 = 156 degrees celcius

cyl 2 = 159

cyl 3 = 161

cyl 4 = 156

cyl 5 = 171

cyl 6 = 132 degrees celcius

 

Rocker cover, front = 65 deg C

middle = 125 deg C

rear = 123 deg C

Radiator average across top tank = 111 deg. c

Thermostat housing top = 126 deg. C

Sump = 96 deg. C

Header pipes, covered with thermotech wrap, measured about 8 inches from head flange

 

cyl 1= 238 deg. celcius

cyl 2 = 239

cyl 3 = 278

cyl 4 = 259

cyl 5 = 288

cyl 6 = 270

 

Seems like the air entering the carb is a bit hot.....ranges from 61 degrees C close to the rocker cover to 43 degrees on the far side. (14X3 inch K&N filter on my Holley).

 

Took it out for a G Tech run.

Today 0-100 km/h in 9.75 sec. (Previous best 9.93 sec.)

0-400 metres in 17.15 sec. (Previous best was 17.26 sec.)

Speed @ end 400 metres 135.7 km/h (Previous best 134 km/h)

 

The timing was bumped up to 18 degrees static, 38 degrees total. Vacuum advance was disconnected. The temperature for today is 23 deg. C

 

Only once I heard the engine rattle with this much advance. Cruising at 50 mph for a few minutes and then slamming the throttle down to the floor brought it on. That was the only time it happened, all other driving styles, the engine is free from ping.

 

I still can't get over the position of the temp guage needle (3/4 hot).....weird to see it there after years of seeing it just below half way.

And the smell of it after some hard runs, reminds me of when I used to borrow dads car and give it a hiding on a Friday or saturday night!! My car hasn't smelt like that for years.

 

So I think I've picked up a few kilowatts, and it feels quite responsive, tip in is great and off the line performance is good too. Do I leave it like this? I'm just worried about the reliability factor now everything is so much hotter than with the 160 degree F. thermostat.

 

Cheers!

[ozconnection]

Ordered some Redline water wetter solution today. When I asked for it from my local spare parts dealer, I got nothing but a blank look ...'huh?'

 

So I searched ebay and found someone here in Oz who sells it. Needless to say, I bought some on recommendation from others in the 'head cooling around cylinder 5' sticky.

 

That's a bloody good read with some great information in there, just takes a while to get through it all .

 

Water wetter is supposed to reduce temperatures by 20 degrees F or so, so I'm interested in using it to guage any performance changes to my engine. If only I could keep the grunt and drop that needle down a bit....and cool off number 5 cylinder a bit too, I'll be stoked.

 

I'm still considering the electric pump made by CSR. A constant/steady 30 psi coolant pressure in the block, even with the standard 13/14 psi recovery system radiator cap would be a good thing and a good place to start . Can I run my L28 @ 40 degrees total ignition advance...we'll see.

[kolonelklink87]

Ordered some Redline water wetter solution today. When I asked for it from my local spare parts dealer, I got nothing but a blank look ...'huh?'

 

Thats a familiar story... second most frustrating process behind asking for assistance at bunnings.

 

On a more serious note, you've been a busy boy lately I'm keen to see some simple solutions to the 5# problem... there was talk of opening some of the casting flashings and such inside the head, i'd be keen on seeing some more about that too! I have cylinder head cutaways if anyone wants to run with that ball I can send photos or lend to locals...

I'd really love to see it pinned down precisely as to what causes the dramatic increase in #5 compared to 4&6 seen in this and other tests... perhaps that might offer an alternative solution complicated tapping and plumbing.

 

 

-pete

[ozconnection]

Yeah, cheers for that Pete, I've been beating my head around lately thinking about all this. I'm with you in that I'm looking for a (straightforward?) remedy to this 'power limiting' ping gremlin.

 

Thought I was on the right path. Drove the car around to visit the rels and the day was hot, 37 out west. Pinged its nut off! Oh dear! Steady state cruising was fine but squeeze the throttle to accelerate and its all over. Low rpm torque is very strong and that's encouraging. There just doesn't seem to be enough thermal latitude with the hotter thermostat on hot days.

 

BUT, I'm going to try out something else first before I change over the thermostat. I have one of those billet CSR L series water pumps in my garage that I was going to use for the coupe's engine. My logic in replacing the stock pump is to obtain at least 30 psi of block coolant pressure from idle to redline. ATM, at low rpm's there's plenty of heat being generated by the torque increases in my engine but poor block pressure, less than 20 psi and that's potentially allowing steam pockets to form and drive the engine into detonation (especially around number 5). The heat gun results prove that.

 

I've also received the water wetter from a dude in QLD. It says that its best efficiency is with just plain water (distilled) so I'll use that. I'll drain and rinse the cooling system and fill it as per recommendations on the bottle. I'll repeat and record the heat gun tests to see what changes I get.

 

In the back of my mind, I'm still keen to do the Y70 head changeover. But the last thing I want to do is to have to rip it back off because of uncontrollable pinging due to cooling system shortcomings. If I can beat or at least increase detonation resistance with the N42 head, then I'll feel so much better about doing the Y70 swap later on. The Y70 may be a better head by virtue of its tiny chambers being more detonation resistant but doing this work is one way, maybe, that the situation can be 'over engineered' to my advantage. Some headroom without riding on the ragged edge if you know what I mean?

 

I've got a few things to do over the break. See how I get on. If I don't see you, have fun in Japan. There's a signed blank cheque waiting for ya if you see anything for the 230/330 .

 

Cheers.

[HowlerMonkey]

I recently became employed again (JM lexus) and the trip is 70 miles round trip on a damn fast portion of the florida turnpike.

 

To keep up with the faster traffic, I am near 4200rpms for much of the trip.

 

I am running a L28 et with the non-turbo flat top pistons and rods.

 

While traveling at around 4500rpms steady state for a while (very little load), hitting the throttle will bring multi-cylinder pinging instantly.

 

While traveling at around 3800rpms steady state for a while, hitting the throttle will bring no pings all the way to redline.

 

This leads me to believe that my cylinder head starts to run hotter just by virtue of higher rpms even with very little load.

 

The water pump in question is a dealership sourced L28 pump with the cast curved blades rather than the straight stamped blades.

 

In my case, I think cavitation of the pump is to blame and not the head's ability to flow coolant.

[ozconnection]

I recently became employed again (JM lexus) and the trip is 70 miles round trip on a damn fast portion of the florida turnpike.

 

To keep up with the faster traffic, I am near 4200rpms for much of the trip.

 

I am running a L28 et with the non-turbo flat top pistons and rods.

 

While traveling at around 4500rpms steady state for a while (very little load), hitting the throttle will bring multi-cylinder pinging instantly.

 

While traveling at around 3800rpms steady state for a while, hitting the throttle will bring no pings all the way to redline.

 

This leads me to believe that my cylinder head starts to run hotter just by virtue of higher rpms even with very little load.

 

The water pump in question is a dealership sourced L28 pump with the cast curved blades rather than the straight stamped blades.

 

In my case, I think cavitation of the pump is to blame and not the head's ability to flow coolant.

 

That's interesting. You're probably right about the cylinder head temperature getting hotter due to engine speed and not just engine load. Your experiences sound similar to mine with my L28 even though our configurations are quite different.

 

I compared water pumps recently and found that the factory units were quite good in design compared to another new aftermarket unit I had. I'm surprised you think that the factory water pump is cavitating at your engine speeds but anything is possible. Most factory water pumps seem to flow their maximum around 5000rpm's (water pump speed).

 

I've looked at a couple of old L series water pumps and it seemed that the aftermarket ones were all suffering from cavitation. There was a lot of pitting and erosion around the paddle part of the impeller whereas the rest of the metal blades looked like new! I've always used coolant so it's not from rust. I just don't think the aftermarket ones are particularly well designed.

[madkaw]

I've been wanting one of those laser temperature guages just for this reason. I think it could be an excellent troubleshooting tool , especially in this scenerio. Can you explain the big difference in the #6 cylinder temperature compared to the others. Are you zeroing in the laser on the head where you would tap for the coolant on 5& 6 ?

[ozconnection]

I think you'll be like me and can't put the thing down!! Great tool for this application like you said. They're not that expensive either. Should have bought one ages ago!

 

Maybe some of the coolant down in the block is flowing into that area because of the large passageways in the back of the block/headgasket/head.

 

Since combustion takes place at the top of the engine in the head chamber, the coolant from the lower parts of the block are cooler. Flowing up into the head at that end, the temps might be cooler because of this.

 

Sound feasable?

[ozconnection]

Some progress today and not .

 

Well, I have the water wetter and decided to continue on with the cooling system mods.

 

I have installed the CSR electric water pump. The gasket that I used was new but didn't seem to fit correctly and I think I tore it as I was putting the pump in. SO! It leaked after I tried to fill the engine with water to rinse all of the waterways of ethylene glycol! Damn.

 

The other thing that was replaced was the fan belt. I had to find one the correct length and a 760mm one fitted perfectly. Fits just around the harmonic balancer and the alternator pulley. Something I didn't expect was that the timing plate is covered by the new position of the fan belt. Buggar.

 

The 16 inch electric thermo fan fits nicely within the confines of the fan shroud and the shroud keeps a little of the factory look, hides all the aluminium brackets and will maintain the cooling efficiency like the stock setup. However, there was some lifting of the shroud from the radiator because of the new support brackets for the fan. I think I can get it flush, but it'll need some more work. Doesn't really matter, I gotta take it all off to gain access to fixing the water pump gasket.

 

The electrics went very well! Having had to replace the alternator not so long ago, I replaced the externally regulated unit with an internally regulated one. As a result of where the wiring harness connector plugged into the regulator, I had complete access to a heavy guage power wire, connected directly to the alternator, a heavy black earth wire and an ignition activated power wire to trigger the relay to turn on the pump and fan. How bloody convenient....didn't have to cut into or splice the wiring harness at all! I used a generic 5 pole, dual output, 30 amp unit. Both the pump and fan power lines are fitted with a 15 amp inline fuse, the CSR pump guys recommending this size and the fan attached to an ammeter to determine current draw. I saw an immediate draw of 15 amps, settling to 8-9 amps when the fan was working at speed. Plugged it all in and it works!! Full of electrical sounds, electric fuel and water pumps and the fan.

 

Now I can't wait to get the pump gasket and shroud sorted, fill it with distilled water and the wetting agent and fire it up. Then I will test to see what the cooling system pressure is. The CSR pump must be efficient, it doesn't spin at particularly high rpm's. It also has an eight vaned impeller......the stock pumps I've seen only have six.

 

Just a question, can I roll the engine to TDC @ No1 and mark the harmonic balancer at another area and use that to time the engine instead? I have an Innova adjustable timing light with a digital readout of the advance and engine rpm's

[ktm]

That's interesting. You're probably right about the cylinder head temperature getting hotter due to engine speed and not just engine load.

 

Look at it this way. If a combustion cycle happened once every 10 minutes, then the engine temperature would not get much hotter beyond ambient. The more frequently you have a combustion cycle, the less time there is for the engine to shed heat.

 

At 1000 rpm, you have 16.7 combustion events per second; at 6000 rpm you have 100 combustion events per second.

[ozconnection]

Finished the install today with a new water pump gasket.

 

All that's left to do is to drain the flushing water and refill the radiator with distilled water and the water wetter.

 

My initial observations were that block pressure is less than 10psi.... this is TOTALLY NOT what I expected. I will do some more testing soon.

 

I started the car today and the engine would not idle when cold. Hmmmmmm, I may have to adjust the mixture strength and reconnect my vacuum advance to manifold vacuum to get more idle torque. I'm guessing that there must be quite a bit of current draw/drag on the engine from the alternator since I've just lost an 8 bladed fan and a belt driven water pump!!! It idled fine once the engine was warmed up though.

 

I may have to switch the fan over to thermostatic control if I can't solve the idling problem. That's assuming the problem is an electrical one in the first place.

[ozconnection]

It seems that all I needed to do was reconnect my vacuum advance to get my car to idle again nicely when cold. Some very minor tweaking may be needed to the idle mixtures in the colder months, but for now I'll leave it as it is.

 

Drove the car round the block and I couldn't detect any pinging....but todays temperature is only about 23 deg. Celcius. Certainly not hot like it was the other day. It felt good and strong and I'll do a G-tech test as soon as I can. Part throttle response is sharper with the vacuum advance reconnected!

 

Now, I will test the engine temps with the laser gun before I put in the water wetter. This will test the new CSR pump and water as coolant setup. Then the water will be dumped, the radiator refilled with the wetting agent and tested again. This will test the wetting agent.

 

Oh, and I just bought an brand new LD28 water pump....I just had to see what all the fuss is about . I'll keep it as a spare for my coupe if I don't decide to run a CSR pump in that puppy as well.

[CamH]

Will you be testing the LD28 pump? I've been considering giving one a shot myself because I have some issues with the car heating up when sitting in traffic on hot days during the summer. Can't wait to read about it.

[ozconnection]

The LD pump will be a few weeks away.

 

I bought it because, in case I couldn't easily fix some problems with the CSR pump, I could revert back to a standard style pump.....but why any old pump when I could use the LD unit!

[ozconnection]

Ah, what the hell, I bought the Moroso Electric Water Pump Drive Kit (63750) and extra drive cog that can spin the stock L series water pump 28% faster last night......to go with my new LD pump. The electric motor is designed to turn big block water pumps...should be overkill for the L Series water pump then. I'm assuming the LD engine has a redline of about 5000 rpm, so maybe the pump is designed to flow a maximum at a lower rotational speed...can anyone confirm this?

 

Today it's hotter, like 30 degrees and after one good rev and back off, then rev again.......straight into detonation...... .......and I should point out that before testing today, I got sick of seeing that temp needle 3/4 hot, so I put in a 180 degree F (82 degree C) thermostat. (Was 190 deg. F) The needle sits just a fraction over half way now and the temps are stable...the needle doesn't budge.

 

This is all fairly drastic stuff to bump the timing a up a few degrees I know....

 

Am I asking too much?? Can the stock N42/N42 L28 combo handle 38 degrees total advance?

 

Not as it is, it seems.

 

(..........block pressure man....it's all to do with block pressure........)

[TimZ]

The electrics went very well! Having had to replace the alternator not so long ago, I replaced the externally regulated unit with an internally regulated one. As a result of where the wiring harness connector plugged into the regulator, I had complete access to a heavy guage power wire, connected directly to the alternator, a heavy black earth wire and an ignition activated power wire to trigger the relay to turn on the pump and fan. How bloody convenient....didn't have to cut into or splice the wiring harness at all! I used a generic 5 pole, dual output, 30 amp unit. Both the pump and fan power lines are fitted with a 15 amp inline fuse, the CSR pump guys recommending this size and the fan attached to an ammeter to determine current draw. I saw an immediate draw of 15 amps, settling to 8-9 amps when the fan was working at speed. Plugged it all in and it works!! Full of electrical sounds, electric fuel and water pumps and the fan.

 

If I read that correctly, it sounds like the fan and pump turn on and off at the same time - is that right? Are you leaving the fan on all the time, or turning the pump off with the fan when the engine coolant temperature falls below some setpoint?

[ozconnection]

If I read that correctly, it sounds like the fan and pump turn on and off at the same time - is that right? Are you leaving the fan on all the time, or turning the pump off with the fan when the engine coolant temperature falls below some setpoint?

 

At this point, yes, the thermofan and the water pump work together.

 

There is no temperature dependancy ATM.

 

I could get a water pump controller later on but what for?.......I'm thinking that whatever the stock setup does, (ie come on when the engine starts and turn off when the engine does) I can duplicate that easily enough.

 

I guess for a turbo engine, there'll be more of a reason to avoid heat soak. A turbo timer could be set up to run just the water pump and thermofans after engine shutdown for a period of time......that would be excellent if you had a water cooled turbo.

[1 fast z]

Ah, what the hell, I bought the Moroso Electric Water Pump Drive Kit (63750) and extra drive cog that can spin the stock L series water pump 28% faster last night......to go with my new LD pump. The electric motor is designed to turn big block water pumps...should be overkill for the L Series water pump then. I'm assuming the LD engine has a redline of about 5000 rpm, so maybe the pump is designed to flow a maximum at a lower rotational speed...can anyone confirm this?

 

Today it's hotter, like 30 degrees and after one good rev and back off, then rev again.......straight into detonation...... .......and I should point out that before testing today, I got sick of seeing that temp needle 3/4 hot, so I put in a 180 degree F (82 degree C) thermostat. (Was 190 deg. F) The needle sits just a fraction over half way now and the temps are stable...the needle doesn't budge.

 

This is all fairly drastic stuff to bump the timing a up a few degrees I know....

 

Am I asking too much?? Can the stock N42/N42 L28 combo handle 38 degrees total advance?

 

Not as it is, it seems.

 

(..........block pressure man....it's all to do with block pressure........)

 

 

 

 

I am not sure what your elevation is, but 38 degrees full is ALOT for a non quench motor.

[ozconnection]

This was written by Braap very recently in another thread that was dealing with compression ratios, cylinder heads and ignition advance. Chances are you have already read what he's written. Here it is:

 

Too common for the L-6 to have to back off ignition timing due to the compression ratio. I have been preaching for some time that the power lost due to the retarded ignition timing to keep it from rattling, for greater than the power gained by the bump in compression ratio. Gain of maybe 7-10 HP max for the compression ratio bump over the paltry 8.3:1, but over 20+ HP lost in retarded ignition timing! open chamber L-6 heads, (E88, N42, N47), have their optimum non octane limited spark advance in the 38-42 degree range.

 

"If you can't get 38 degrees total ignition advance above 3500 RPM at WOT, (N/A), with E-88, N42 or N47 head because it is rattling, you are laving HP on the table."

 

I as many other have noticed with the L-6, it is highly sensitive to detonation. With an aluminum head, it should be able to handle 10.5:1 compression ratio N/A on premium pump with no rattling, (many Chevy, Toyota, and other valve designs do just fine), but far more often than not, the Datsun L-6 will rattle at anything above 9.5:1 comp ratio on prmeium pump gas! Why? I have my theories and I firmly believe it is rooted it eh coolant through the head which this thread address. Again, just my theory...

http://forums.hybridz.org/showthread.php?t=125186

 

 

 

In short, I do not endorse L28 builds with flat top pistons and E88, N42 N47 heads for ANY street application unless a thicker head gasket is used to drop the compression down to below 9.7:1 or so. If flat tops are is on your must have list, then I recommend the P79 or P90 head.

 

I live near Blacktown in Sydney, NSW. The elevation here is 57 metres above sea level.

 

It seems that Braap was able to achieve 38 total advance on an engine build similar to mine many times. His 'concern' was that it was cylinder head cooling and its deficiencies that were limiting ignition advance and power production.

 

My 'journey' is to see for myself if the theory of insufficient coolant pressure around the head contributes to this as well. What I'm concerned about is the CSR pump isn't providing the coolant pressure I thought it would.

 

I don't want to jump to any conclusions too soon without hearing from either CSR or JeffP on this, but I wonder if this was part of their design criteria.

 

Davies Craig have some videos on their website which I found interesting to watch.

 

 

http://www.daviescraig.com.au/Electric_Water_Pumps-list.aspx

[kolonelklink87]

on a side note... has anyone ever done a comparative assessment on the difference on cooling efficiency between heads? I feel very silly but I only just noticed today that among the casting (not machined) differences between my early and very late e88 heads there is a notable difference in the arrangement of coolant passages on the port side of the head! I haven't read anything comparing the changes in the coolant passages between early and late heads - though it may very well have been overlooked by yours truely.

 

Cheers,

Pete