Okay, Now I'm Completely Convinced: ALL Original HG's Are Actively Failing!

[bjowett]

I like the heater valve idea, Scott.... curious though, some of the hottest coolant in the engine will be dumped right back to the intake side of the waterpump.

Forced induction won't have a ice problem at the t-body, NA engines could in cold weather.

Block heaters make great warmer uppers...

 

[SUMOTOY]

I like the heater valve idea, Scott.... curious though, some of the hottest coolant in the engine will be dumped right back to the intake side of the waterpump.

It goes there as normal routing from the heater circuit anyway. Given it's heat, maybe a small cooler in the circuit could reduce that temp. I'm not sure I'd worry about it tho, it's going in at the same place as the water from the radiator return. So there should be no vapor lock at that point. I have seen turbo water returns actually cause vapor lock many times, including with my 22RET 4R. Easily solved by putting a trans cooler in the offending hot line.

Forced induction won't have a ice problem at the t-body, NA engines could in cold weather.

I always thought that this wasn't an ice problem, that this was a tip in throttle driveability issue during warmup.

Block heaters make great warmer uppers...

I agree, I bring a couple to Steamboat every year (the magnetic iron type), and have even run the extension cord out my front door at home if overnights will drop below 10degrees. The problem I had was finding a place to put it where it would stay. I ended up plunking it at the exhaust manifold shield, not the ideal location, but it worked. I suspect doing this right would involve a thermostatically controlled permanent bolt on heater.

Scott Justusson

 

[MH_Stevens]

We were getting dangerously close to my off the wall question during my head gasket replacement as to whether I should try to heat the block and install the cold head on it quickly so the block was essentially half heated in terms of the expansion. I'll thank nobody for bringing that one back on line -heh. Who knows what evil that might have wreaked. It might have reduced the peak hot temp expansion difference, but for me the deal breaker was that then the gasket would be under tension all the time with a cold engine.

Wonder if we can get someone to start importing the iron version of the aluminum heads we got on the 1FZ? Heck, we could send them all to Robbie and as we all do HG replacements, he could sell the aluminum heads from our trucks nationally to non Mudders to defray our costs of getting the iron ones. He'd be busy refreshing the iron heads for us, then selling them out into the non Mud world to a population of 80 owners needing heads that's bound to be growing every year....

DougM

But the problem is the gasket not the iron to aluminum interface, no?

 

[semlin]

Regarding the possible relationship of the EGR to the heat problems at #6.... IIRC, the Aussies don't have EGR on their version of the 1FZ-FE engine. They also don't report anywhere near the number of HG failures that we have seen over the last 5 years. I am convinced the two are related knowing that there is nothing that we here in NA can do about it.

-B-

Interesting, I wonder do they have a different head or just a plug where the EGR pipe mounts? If the latter they would still have the exhaust passage in the head? If the former and if they don't have h/g issues then an emissions unfriendly solution would be to install an aussie head, block off the EGR valve inlet on the plenum, and somehow fool the ecu (not too hard if you have a 93-94 and not even necessary if you have a federal 93)

 

[bjowett]

One could also find a way to install an external EGR cooler, such as this unit that comes on a Toyota Camry 3VZFE.

 

[Beowulf]

... then an emissions unfriendly solution would be to install an aussie head, block off the EGR valve inlet on the plenum, and somehow fool the ecu (not too hard if you have a 93-94 and not even necessary if you have a federal 93)

Or replace the old style HG with a new one every 200k miles or so.

-B-

 

[semlin]

One could also find a way to install an external EGR cooler, such as this unit that comes on a Toyota Camry 3VZFE.

the pair valve outlets on the exhaust manifolds on the 93-94 might work for that if you switched the manifolds into a 95-97, but you would need an EGR valve with a pipe union that faced to the PS side instead of straight back.


or as B mentions, you could just replace the gasket every now and then

 

[Rookie2]

Or replace the old style HG with a new one every 200k miles or so.

-B-

Shoo.. not me, only thing I'm replacing mine with is the new style head gasket.

 

[Farley]

I apologize if this has been covered, but would a compression check / leakdown test show whether or not a HG was bad - before the obvious overheat symptoms?

 

[IdahoDoug]

I did a compression check on my engine by coincidence a few thousand miles before it failed, so I don't think it's a good diagnostic. Would it tell you what was wrong when it failed by doing another test and seeing a difference? Don't think so as some have gotten very HIGH readings on the damaged cylinder due to coolant in the rings, etc. A leak down might help, but there again if the gasket has not failed - no leakdown issue will be noted. Once it's failed - yes it is a good indicator if you've tested BEFORE and have data to compare.

I think neither is worth doing for this purpose.

DougM

 

[turbocruiser]

Okay fellas, another completely convinced statement here ... my head was warped! The shop took off 8 thousandths to get the thing totally flat!!! Keep in mind I had absolutely NO overheating, absolutely NO external leaks, apparently NO internal leaks (as measured by blackstone), the thing ran as strong as strong gets and almost never went above 90 celsius even on extreme runs. Things that make you go HMMMMMM?!?!? Any thoughts? Seems we're speaking of problems with BOTH the HG design (old vs. new) AND the long long length of this head. Agreements or disagreements are absolutely welcomed! Which comes first??? A bad HG or a warped head, does one cause the other or are they totally independent of one another??? Keep stirring the pot folks, this is fun!!!

 

[alaskacruiser]

turbo - I know you take great care of your rig, but could this have happened due to overheating at some point by the PO?

 

[semlin]

that's a really big warp. i boiled my truck dry and blew the h/g at both ends and it was only warped 3 thousandths. the shop where I have it told me that they rarely take as much as 5 thousandths off a head as part of their effort to talk me out of shaving ten thou off.

Also, did you do a vacuum test on the valves? you might have displaced some with that much warp

 

[turbocruiser]

turbo - I know you take great care of your rig, but could this have happened due to overheating at some point by the PO?

Its possible but the PO was also overly anal about all the maintenance things. But, it is possible.

 

[turbocruiser]

that's a really big warp. i boiled my truck dry and blew the h/g at both ends and it was only warped 3 thousandths. the shop where I have it told me that they rarely take as much as 5 thousandths off a head as part of their effort to talk me out of shaving ten thou off.

Also, did you do a vacuum test on the valves? you might have displaced some with that much warp

The machinist told me its really not all that awful - with such a long surface such warpage is completely common - maybe he was trying to stop some angina but that's what was told. The machine shop serviced all the valves as part of my order - they are all as new now.

 

[IdahoDoug]

Informationally, a warped head will rise in the center which would not change or increase clamping pressure at the ends where we're having issues. So, unlikely warpage is itself related to HG failure, though certainly a heat episode hot enough to warp the head would damage the gasket and contribute to later failure.

DougM

 

[Rookie2]

So if this is done as PM on a fairly low mileage vehicle (say 100k), is it necessary/advisable to do a head mill and valve job. Obviously you get the head checked as a minimum, but my thinking is you can only do some much of each over the long hall, so using up part of this at lower mileage, could limit what you can do in the future... say at overhaul.

I need to get Doug's DVD. When's the enhanced 2.0 version coming out .


Thanks,
Rookie2

 

[IdahoDoug]

It's on Version 3.0 now... Just shipped a bunch an hour ago.

DougM

 

[turbocruiser]

It's on Version 3.0 now... Just shipped a bunch an hour ago.

DougM

So Doug, whaddya add to the thing? How much are annual upgrades???

 

[semlin]

milling is not needed if the head is not warped so in a PM situation it should be optional. taking ten thousandths off increases compression = more oomph but it limits your options if the head blows a second time since maximum milling from stock without adjusting timing chain is about 15 thousandths and we have just witnessed a 9 thousandth warp.

need for a valve job depends on results of a vacuum test by machine shop. I did mine because the 2 centre exhaust valves were on borderline but at 155k all others were perfect and the head shop believed the two were only off as a result of distortion from the warp in the head which I think I had only just picked up.