Offical 1FZ head gasket debate (1 Viewer)

[mrsalty]

I have run advanced timing for 90,000 miles with no rattles ever. I wasn't speaking of us running the timing past factory anyway. i was referring to the computer being able to add more timing before spark knock for better performance from the factory. Aluminum will allow this.

OK not to highjack here (but I guess I just did), but are you saying that higher octane gas will allow the computer to advance the timing such that SOME? performance can be gained (at the expense of other factors)? IF this is what you are saying, I might have a data point on that. If I am confused, act as if this never happened, and I will disavow any knowledge therof.

Thanks,

Chris


94FZJ 135K 2.5 OME 285 Cooper ATR CDL Pin 7 DD

 

[semlin]

i don't know if folks are saying that in this thread but i think it is true. Higher octane impedes knock. this impedes the knock sensor from retarding your timing. However running higher than recommended octane masks the symptoms of a disease you still have. something is causing the knocking and it should be fixed. Running a tank of higher octane is a diagnostic tool not a solution.

 

[concretejungle]

Mr. Salty (chris) just for your info, and i want to keep this thread on the HG, but i had a knock and was running 93 octane to eliminate the knock. When i would run regular (87)fuel i would get a lot of knocking and could feel the computer retarding the timing and losing power. BUT, i recently decided to run the 93 out, fill it up on 87 then unhook the battery to reset the computer. Now i have been running 87 octane and seems to be performing similar to the 93. Just for your info. ALmost like the computer after reset thought it had 93 in it. I think those that switch back and fourth between octane fuels are actually not helping the situation.

Now back on topic.

Powderpuff............. i mean robbie, do you feel that the newly designed HG, if replaced, is a good enough design to say to yourself that now it's been replaced it should be good to go for a long long time and basically forget all this HG issue?

 

[powderpig]

Ok I am back for a while. Yes the new gasket is that much better. The diagram from Ravan (Ithink) shows the some of the metal that is between the cylinder (More blow out pretection). Smaller holes to slow the flow at #6 as well as some of the other areas, more metal around other parts of the gasket. I have not had any problems with anyones HG after the replacements or on any of the rebuilds we have done. The olderest for me is a LX450 we did almost 4.5 years and lots of miles.
A compression test can create more pressure in the cylinder than a Cylinder Leak down test. So If I see a low compression I can then use a cylinder leakdown test to see where it may be going. As forbubbles and Overheating. these are also clues. Yes if I was a person traveling many miles from no where I would want the most reliable truck I could get, this mean I would do a HG as maintance. If the truck is just a daily driver and it did not go on trips where I could not get good work then taking a chance with the headgasket is just that a chance. If the truck is something that I am only keeping for a short time, who cares if it strands you. If it is something you plan and keeping for a very long time then why not do the maintance.
Just some other thoughts as to why HG go or fail. Todays engines and electronics allow the average person no to have to wait for warm up period. I think some people that just get in the car and take off and take off hard with out warming the engine do it a disfavor. this allow the head gasket and the head to move more and can cause coolant creep( I have seem lots of this where the head gasket to block has a layer of rust) and I think it come from the above sernio. If we look back to the older cruisers with Carbs the low compression, rich enviroment of the cylinder and the warm up time all lead to longer head gasket life. Now today, shorter warm up time aluminum head, leaner cylinder enviroments all create problems. Enter the Owner that does not do much to the car(perfiect soccer mom car, which alot of you guys love), then sells it to some one who loves cruisers and what a supper reliable vechicle. The PO sets you up for some failures, because of the lack of proper maintance, not just the maintace they think it needs,(mostly no one reads the book, just trust the dealer or the local grease monkey).
So really what does it all come down to, personally if I buy a 96-97 crusier for my wife (instead of a 100 series), one of the first things i will do is the maintance of all fuilds, all the axle work, pull the head mill it some and have the valves done at this time, Clean all the carbon out and put it back together. Now is this for every one, I do not think so. but if the HG goes who will you blame, If you have the knowlage here, then you have only your self to blame, you have been warned. Others may blame toyota, but not me. They did the best with what they had at the time.

powderpig was a nick name when I lived in Ak for the back county power I chowed on in the winter. I was also a poucher, meaning I could be in the best powder before most other could be there. OOOOO I miss the back country of AK, the glaciers in the some have some sweeeeeeeeet powder. O yea I ski tele.
good luck with your choices. later robbie I am off to do some honey do's before the days end.

 

[powderpig]

O yea I forgot we use the consumer version of EASE diagnostics, have been for several years. Have not price them in a while, but works great for the toyota. Yes it runs on a PC laptop (have not tried on a MAC running window emulation yet). So that is what we use. later robbie

 

[mrsalty]

Mr. Salty (chris) just for your info, and i want to keep this thread on the HG, but i had a knock and was running 93 octane to eliminate the knock. When i would run regular (87)fuel i would get a lot of knocking and could feel the computer retarding the timing and losing power. BUT, i recently decided to run the 93 out, fill it up on 87 then unhook the battery to reset the computer. Now i have been running 87 octane and seems to be performing similar to the 93. Just for your info. ALmost like the computer after reset thought it had 93 in it. I think those that switch back and fourth between octane fuels are actually not helping the situation.

Now back on topic.

Powderpuff............. i mean robbie, do you feel that the newly designed HG, if replaced, is a good enough design to say to yourself that now it's been replaced it should be good to go for a long long time and basically forget all this HG issue?

Good point on topic, I will post another new thread. Thanks for the info.

Chris

 

[txtortoise]

Personally, my brain is wired to look for Robbie...I was wondering who this PowderPig was working at Christo's.

Kinda like Oprah or Prince, (or the Duke), basically a single honorific that everyone identifies with...and one no one on this list would dare copy or sequence, e.g., Robbie2.

 

[MH_Stevens]

Learning the in-dash temperature gauge is just an "idiot warning" light and being concerned and involved with this HG failure debate I set out to measure some accurate temperature on my rigs engine today.

The air temperature was 98F. I drove 25 miles with four people on-board with the a/c on. The idiot temperature gauge was in the middle - 3 'o' clock position. I parked and left the engine and the a/c running and shot these temperatures:

Radiator top hose 180F
Radiaitor fins 152F
Thermostat housing 175F
Air intake moniforld 172F
Transmission pan 164F
Transmission cooler 145F
Head at #1 242F
Head at #6 245F
Block at front 192F
Exhaust manifold at front 530F
Exhaust manifold at rear 502F

Are these numbers normal? Do they mean anything? At what temperature is an "overheat" defined? What temperature will warp a head?

 

[e9999]

Learning the in-dash temperature gauge is just an "idiot warning" light and being concerned and involved with this HG failure debate I set out to measure some accurate temperature on my rigs engine today.

The air temperature was 98F. I drove 25 miles with four people on-board with the a/c on. The idiot temperature gauge was in the middle - 3 'o' clock position. I parked and left the engine and the a/c running and shot these temperatures:

Radiator top hose 180F
Radiaitor fins 152F
Thermostat housing 175F
Air intake moniforld 172F
Transmission pan 164F
Transmission cooler 145F
Head at #1 242F
Head at #6 245F
Block at front 192F
Exhaust manifold at front 530F
Exhaust manifold at rear 502F

Are these numbers normal? Do they mean anything? At what temperature is an "overheat" defined? What temperature will warp a head?

(pet peeve) unless you have a really fancy pyrometer and know the emissivity of the surfaces, these numbers are likely not accurate in absolute terms, so only useful for comparison at different times...

 

[semlin]

michael the only benchmark I have seen is coolant temperature. do a search on "overheating" but I think anything over 200 degrees is bad ,210 is the a/c cutoff and 220 is very bad for the factory ecu temp sensor (actually that's more like a half assed recollection i can't recall). the temp sensor is around the t-stat i think but maybe not as I recall the ECU temp sensor is separate from the dash temp sensor.

turbocruiser found a greddy part with an aux temp sensor bung you can splice into the upper main rad hose and then easily run a mechanical temp gauge. you can also get an a pillar pod to mount the gauge. i imagine the temp reading at that point might differ from the factory point but it is all relative and you would obviously note a sharp uptick in temp.

if you can get an ob2 realtime readout of engine temp using a good scanner you could try to relate it to the surface readings you have noted. my view it's not worth the effort as surface temps would not be as informative as fluid

 

[MH_Stevens]

(pet peeve) unless you have a really fancy pyrometer and know the emissivity of the surfaces, these numbers are likely not accurate in absolute terms, so only useful for comparison at different times...

I use this gun in the brewery. Always select or make the read area as close to BBR as possible and its accurate to + or - 3F at the ranges quoted.

 

[Gumby]

michael the only benchmark I have seen is coolant temperature. do a search on "overheating" but I think anything over 200 degrees is bad ,210 is the a/c cutoff and 220 is very bad for the factory ecu temp sensor (actually that's more like a half assed recollection i can't recall). the temp sensor is around the t-stat i think but maybe not as I recall the ECU temp sensor is separate from the dash temp sensor.

I would be interested in the factory limits as well. I think your numbers are quite low. The t-stat opens at 195. The engine routinely runs over 200. The fan doesn't even kick on in a GM electric fan system until 220.

The ECU temp sensor is almost always seperate from the guage sensor.

 

[RavenTai]

IIRC all 3 temp sensors are on the left side of the engine, one beign the ac switch, ac is cut off at 226 back on at 217. there is one sensor for the numb idiot gage in the cluster and one for the ECU

 

[e9999]

guys, I hope you're watching the HG poll out there, cuz it's gettin' scary...

 

[powderpig]

It not scarry to me. I know I have stated more on this and have made similar statements about the Head gasket. MH, It may run great for a while and may serve you well entil it goes in some scluded spot on the baja. Any how, The after market water temp will spike more and will more than likely give you slightly different readings then the stock spot. I have thought about dirlling the side of the block for a small sensor, But most of the places that have the length inside to house a sensor, the wall is almost too thin. We have at the shop drilled on the hard pipe going frmo the head to the radiator. This show some real good spikes and would take having to relearn the guage against a computer. It spikes when the t-stat flow and cools when it closes(I would guess the geddy system is similar) .
I do agree that the hand held is not going to give the most reliable results for reading temps, but can give you some information as to what is going on. I some use this to see cylinder temps along the exhaust manifold to see if injectors are working the same flow. Any hoooI do think something that plugs into the stock computer and works off the temp sensor for the coputer would give you the best indication of the temp inside the engine. Some thing to remember is the temp is not the same through out the block. It is hotter at the back of the engine, how much you ask. I do not know but do know it is hotter. That is why the made some the mods to the new headgasket to allow more heat soak in the coolant before it moves.


Some computer glich desided I was no longer a memeber. We had stuff going on at the shop and I did not have my computer up, so I did not recive e-mails. I finally contacted woody who told me I would have to registar againon Mud. So I did, robbie just sounded booring so I pick something I could get tessed about Powder Puff nono, its powderpig. I am off to Alaska for a short visit to help my dad move to washington state, so if I do not get on his computer is down and I will be back next week. Keep the HG debate alive. later robbie

 

[njfzj80]

Vibration

I wonder if vibration is more pronounced in the aluminum head (with respect to the iron block), and by how much. Their abilities to dampen vibration differ. This idea coupled with both material's response to heating/cooling may contribute to premature failure of the HG.

 

[turbocruiser]

Any how, The after market water temp will spike more and will more than likely give you slightly different readings then the stock spot. I have thought about dirlling the side of the block for a small sensor, But most of the places that have the length inside to house a sensor, the wall is almost too thin. We have at the shop drilled on the hard pipe going frmo the head to the radiator. This show some real good spikes and would take having to relearn the guage against a computer. It spikes when the t-stat flow and cools when it closes(I would guess the geddy system is similar) . later robbie

Not that I would ever want to argue with anyone of Robbie's expertise, and especially not with Robbie himself, but I can verify that there are no "spikes" when using the Greddy gauge in the location i installed it. As Robbie stated, there surely would be if you installed it in the regular location where the extra bung is on the hard pipe going from the head to the radiator. Beowulf helped me figure out why putting an aftermarket gauge in the regular spot (again, where the extra bung is on the hard pipe going from the head to the radiator) would produce these spikes. Some of the reasons include how close it is to the outlet of the head, and how the various coolant bypass lines are routed and returned around that area. Add to those things the fact that the coolant return for the turbo housing dumps into that pipe using the extra bung and you surely would have some serious temp spikes right there in that hard pipe. However, the area I installed my Greddy gauge is a good eight inches past those points and by then all the various sources of hot coolant from head, bypass lines, and turbo lines have mixed around and allowed an accurate average temperature to show on the gauge.

For sure this location will produce different readings than the stock sensor location but then again it is indeed much more accurate than the stock gauge and as such it offers me incredible peace of mind to know EXACTLY what the temp of the coolant is just before it dumps to the rad. Also, in my case, the stock sensor location is not going to give me much information on what the turbo is dumping into the system because by that point the coolant the turbo dumps has already gone back through the rad.

I've posted some other options. One is an HKS coolant temp sensor/additional fan controller.

http://www.hksusa.com/products/more.asp?id=1697

I'm seriously considering the HKS even though I have the Greddy stuff for two reasons. One, it truly tells the temps at the stock location, and two, I might still add the JDM additional fan like CruiserDan has so this thing would control that fan.

Lastly, one thing to note. I always cringe when I hear some of the temps people post up here such as 226 when their AC cuts out. To me this seems seriously high, dangerously high in fact. To date I have never had a temp go over 98 celsius which is approx 208 degrees farenheit. This is running the rig super fast up super steep slopes for stretches upwards of two to three minutes. I cant imagine consistently hitting 226, having the AC cut out, and just continuing to drive - seems sure to blow the big gasket. Anyways, again, not any at all an arguement against Robbie, just a verification that if you can get the aftermarket gauge upstream of that dump spot in the hard pipe, you will get a more accurate average temperature of the coolant coming out of the engine and going into the rad. HTH.

 

[e9999]

I'll add to this a couple of things:

- seems to me that it may be wise to either periodically test or replace the OEM temp sensor on the engine. If this thing goes, it could create some serious trouble. Probably as simple as putting it in boiling water.
- those of you who like the pyros so much, you can get an inexpensive contact thermometer. These are surely more accurate since there is no emissivity error. If you clean up the surface real well, you could then calibrate your pyro against those readings and now have much better numbers. Of course, you'll have to keep the surfaces clean to measure anything accurately later on too.

 

[powderpig]

Well it is good to know that you turbo with the Geddy stuff get a good steady reading, with out too much spiking. I would of thought different with the type of flow through the hose. Thanks for the heads up. I usually only take offence when some one challanges me at work (Big smile). These formums are for discussions and for every one to contribute (except John Shotts (big smiles again)). Any how no one person can try everything and their is more than one way to skin a cat. If my dad computer is up I will keep looking in if I can. later robbie

 

[hobbes]

e-

I dunno. Those things are pretty simple. I'm more worried about the gauge readings.

Correct me if I'm wrong, the temp sensor is fine but the TEMP GUAGE dumbs down the readings. IOW, doesn't the computer get its (accurate) reading from the same sensor? I'd love it if someone could figure out a way to make the OEM gauge useful. I think RT put out a call for a gauge to play with, but I'm not sure if he ever got one.