25 RA is for a MHG (probably an HKS unit). It means Roughness Average, or how smoothe the surface of the head and block are. A MHG has to be pretty smooth to ensure a proper seal 
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.Tell me it aint so....
- Thread starter JSHeinrich
- Start date
jdub said:And it could be a combination of things too...air in the system from a leak, fan clutch, radiator cap. They can all add up to cause weirdness in the cooling system.
Oh course, Andy could be right as well...a BHG. It's worth it to make sure the cooling system is up to speed 1st.
Chris - You want to run a clutch if you stck with the stock fan.
What would be the downsides of running an aftermarket fan that was bolted directly to the waterpump pulley John? This is also assuming the fan is the same size diameter as the stocker and is positioned in the fan shroud at the right depth....
The engine would take longer to warm up, and it would get really annoying to hear the fan roaring away constantly, especially on the freeway, big HP loss...
Ok I just did an oil change and the oil was like a milkshake big time. I would take pictures but my camera is broken. My fill tank for the radiator has not lost anything but when i pulled the cap off the radiator it was very low, so for some reason it's not pulling anythign from the fill tank.
With a stock head gasket, I still have to get the head machined to make sure it is not warped, correct? I can't see it being anything else other than a BHG but my dad is trying to think of 1000 different things because its a lot of work and he is tyring to make sure its nothing else.
Any tips on the bhg repair would be greatly appreciated. As well as anybody else's opinion on what I should do..
BHG :squirt-mo
With a stock head gasket, I still have to get the head machined to make sure it is not warped, correct? I can't see it being anything else other than a BHG but my dad is trying to think of 1000 different things because its a lot of work and he is tyring to make sure its nothing else.
Any tips on the bhg repair would be greatly appreciated. As well as anybody else's opinion on what I should do..
BHG :squirt-mo
johnathan1 said:
Warming up the engine has nothing to do with it. The thermostat stays closed untile the engine is warmed up to that thermostat's specific temperature range
. That's like saying a bigger AL radiator is going to make it take a long time warming up... The radiator would have a bigger cooling capacity, thus giving the coolant more time to cool down once it's in the radiator before it gets flowed back into the engine. The fan bolted up to the pulley would help cool the coolant down while also running at the engine's RPM speed . The howling isn't going to bother me. As far as HP loss goes, it's not that big, I have already removed the A/C from my car, plus I'm going for 450-500 reliable HP.
starscream5000 said:
You would need some sort of spacer to mount the fan at the stock depth...otherwise, you will greatly reduce it's efficiency. The silicone fluid in the clutch is used to drive the fan and cool the engine at lower engine speeds. As RPM increases the drive fluid allows the fan clutch to slip, increasing engine efficiency when less fan-assisted air movement is needed due to higher vehicle speeds. A direct drive is going to use more engine power at high rpm.
Here's the danger (besides the noise johnathan mentioned), the higher rpm of a direct drive will increase the stress on the fan due to the force exerted pulling air at that engine speed. The stock fan is plastic...you could easily exceed the structural limit of the fan and throw a blade...not good. If you use an aftermarket metal fan, make sure it's very stiff...otherwise the blades could bow at high rpm, again reducing efficiency.
The stock fan system is designed to be run with a clutch...aftermarket fan or not. Chris, IMO you're asking for problems...like we need another issue on the Supra cooling system. I would run the clutch or replace the stock fan/clutch with the FAL dual electric fans.
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JSHeinrich said:
I'm sorry to hear that man...that pretty much confirms a BHG...looks like Andy was right.
DO NOT run the motor any more! Coolant in the oil can destroy the bearings...you don't want to add rod knock to your problems!
A MHG would be the best, but that would require pulling the motor to have the block decked. A stock HG will work fine...you can boost to 14 psi safely on a stock HG. I would get the HG from Toyota.
Use ARP bolts or studs torqued to the spec sheet that comes with the ARP hardware. Use moly for lube...make sure you use the ARP spec for moly
Torque using the TRSM pattern...in fact, make sure you read the TRSM on removing/installing the head a couple of times. Don't forget to use some RTV on the timing front cover or you'll have an oil leak. Removing the hood makes getting the head out a bit easier.It wouldn't hurt to have the head worked...decked, valve job, replace seals (cam and valve), shim clearances checked. Have the head checked for flatness and decked to the lowest RA (smoothness) as possible. Make sure all the old HG material is removed from the block. I would clean the tops of the pistons with Mopar Combustion Chamber Cleaner.
You will need (off the top of my head):
HG, exhaust manifold gasket, intake manifold gaskets (2), CPS O-ring, valve cover gaskets & grommets, and cam seals. If you do the valve job...valve seals. Check the water outlet on the back of the head...replace if corroded. May be a good time to replace the timing belt too, if yours has over 70,000 miles on it.
Since you put it that way, I'll just rebuild my stock fan clutch during the rebuild . I will be using an Electric fan, but it's going to be where the A/C was before, in between the intercooler and radiator...
. I will be using an Electric fan, but it's going to be where the A/C was before, in between the intercooler and radiator...jdub, you said use moly for lube...is thata type of gasket maker?
Also, what are the ARP Head stud and ARP head bolts? I mean I only need headbolts correct?
Sorry, i'm definately a newbie when it comes to extensive work and id on't want to go through this process twice or order stuff I don't need. I really appreciate all of your guys/gals help
EDIT: Hey, I found this page racpages.com. They say everything is oem replacement parts. If i needed just for instance bearing or exhaust or intake valves, does anyone recomned me getting them here or should I just go to a toyota dealership?
Also, what are the ARP Head stud and ARP head bolts? I mean I only need headbolts correct?
Sorry, i'm definately a newbie when it comes to extensive work and id on't want to go through this process twice or order stuff I don't need. I really appreciate all of your guys/gals help
EDIT: Hey, I found this page racpages.com. They say everything is oem replacement parts. If i needed just for instance bearing or exhaust or intake valves, does anyone recomned me getting them here or should I just go to a toyota dealership?
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ARP studs are the only way to go . ARP Moly lube is a lubricant that delivers a very accurate torque reading when tightening nuts and bolts down. Moly is used when assembling engines.
. ARP Moly lube is a lubricant that delivers a very accurate torque reading when tightening nuts and bolts down. Moly is used when assembling engines.
Get the ARP bolts instead of the studs..... especially trying to put the head on the block while it's still in your car, save yourself some time. They are cheaper, and easier to use, and will work as good as studs for you. And yes the studs and bolts will hold the same amount of power, the only difference is where the stress is placed, on the threads in the block, or the bolt. It really doesn't matter.
Keep the fan. If it's on FULL blast on the highway, replace the fan's clutch, very simple. Electric fans on a street supra is money poorly spent for performance, and the risks are higher.
Keep the fan. If it's on FULL blast on the highway, replace the fan's clutch, very simple. Electric fans on a street supra is money poorly spent for performance, and the risks are higher.
Soory to bring this back from the dead.
I bought the felpro gasket kit, arp head studs. When I put the hg on, should I use any kind of gasket sealer like permatex copper spray? Or should I just not put anyhting on it at all?
I bought the felpro gasket kit, arp head studs. When I put the hg on, should I use any kind of gasket sealer like permatex copper spray? Or should I just not put anyhting on it at all?
buckshotglass
I love all your sounds.
buckshotglass said:
I'm not using a MHG.
I'm in the process fo taking the head off to get it machined. I have the felpro hg i'm using. I just need to know that when I go to put it on should I put anything on it?
Using the spray on a composite HG is not a problem and can help fill in small imperfections. Assuming you did not deck the head/block, remove all old HG material. Make sure the HG is properly aligned.
Just make sure you torque the ARP stud to spec (81 ft/lbs) using the TRSM pattern. Loosening the studs, then re-tightening 3-5 cycles before final torque will give you the most accurate torque settings using moly as lube.
Also make sure you use RTV along the top of the front timing plate in the TRSM locations. Otherwise you will have an oil leak.
Just make sure you torque the ARP stud to spec (81 ft/lbs) using the TRSM pattern. Loosening the studs, then re-tightening 3-5 cycles before final torque will give you the most accurate torque settings using moly as lube.
Also make sure you use RTV along the top of the front timing plate in the TRSM locations. Otherwise you will have an oil leak.
buckshotglass
I love all your sounds.
Thanks jdub.
I'm going to take off the head and take it to a machine shop where my dad knows the owner (hopefully I get a deal). If its gogint o cost too much now I might not get the head decked (considering its not in that bad of shape).
GO EAGLES
I'm going to take off the head and take it to a machine shop where my dad knows the owner (hopefully I get a deal). If its gogint o cost too much now I might not get the head decked (considering its not in that bad of shape).
GO EAGLES