Engine Rebuilding options for S/C (1 Viewer)

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NLXTACY

Wits' End
Joined
Dec 7, 2007
Threads
200
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Location
Medford, OR
OK so the LX goes into the shop on Wednesday. Form there the engine comes out by Friday and off to Martin Davidson to have the engine completely rebuilt. So I am going to throw out all of my thoughts and questions and see what can be solved. I have not rebuilt a motor professionally in almost 20 years so I'm a little concerned because I know most of that knowledge is gone. My last rebuild was on my 68 Camero's 396. That was in the 90s.

So I am trying to maximize the time I have with the truck while the engine is out and start to work on everything I can during that time. I have spent the entire day reading all the S/C threads trying to educate myself and on occasion I am left with more questions then answers.

I am leaning towards boring out 2mm over but I am starting to question myself for doing so. 2mm will lower my compression and allow more boost but is it really needed? Is 1mm plenty? .5mm?

COMPRESSION
What is the optimal compression ratio I am looking for? Because I do not know the flatness of the block and I do not know if it will need to be decked. If its decked then sure at least a thou comes off. That changes the thickness of the Cometic gasket. So I really can't order the gasket until I know the deck height. Then off course with Cometic I can adjust the compression as needed. Again, some ideal numbers to shoot for would be very very helpful.

HEAD GASKET
Cometic seems to be the obvious choice here. The site can be found here: Cometic Gaskets
Again, I can't really order until I know what thickness I will need.

THROTTLE BODY
The throttle obviously has to come off and I will have it sent out to be cleaned up and rebuild BUT the question is, while its being rebuilt should I go ahead and get the throttle body bored to increase the throat. I did this on my 4Runner and it made a damn noticeable difference. But in doing so to the LX will it cause problems to get properly metered air/fuel?

VALVE COVER
Keep stock, anodize, powder coat, ceramic coat??
I can get anything under the sun anodized for free. Everything else costs. Anodizing isn't the most steadfast at protection but its not like the valve cover gets abuse other than oil and mud. On the other hand I will be ceramic coating some parts and could just throw that in as well. Or I could just go wild and color powdercoat it. I feel like doing something with it while I have it off.

PISTONS/RODS
Back in the day everything was about TRW. No idea what the new hotness is. I've heard about Hypatec pistons with HPC coated crown and Teflon coated skirts. What else is out there? Does Toyota have +1mm or even +2mm for that matter?

FUEL PUMP
Should I just replace with a stock one, go with the Supra or switch to Bosch or Walbro? I like the idea of having it be a drop in replacement which is why I most likely going to go the Supra route.

INJECTORS
Stay with stock but have cleaned and blueprinted: RC Engineering: Fuel Injector Cleaning
Or switch them out with upgrades fro RC Engineering or EFI Hardware or just use the WRX Blue as suggested by Landtank?
Is the stock fuel pressure regulator up to snuff or should that get an upgrade as well? Cool calculators to figure out injector sizing:
Fuel Injection calculator

CYLINDER HEAD
Martin Davidson does some really good work and way back when he was the competition. Irony. Anyway I wasn't going to do anything in particular to the head itself but I WAS thinking about grabbing the head from him when its torn apart and spend the weekend porting and polishing it. I happen to have a complete head gasket kit and I could scribe the head using the gasket and get some carbide bits and flapper wheels and polishing compound and start porting and polishing the head myself. I could I could go nuts and make block offs to do a "home version" of blueprinting. I don't have to do any traveling for at least a month so I am seriously considering this. Having this done as a service seems to be wildly expensive so if anyone has suggestions please let me know. Otherwise its just pressure test, probably new springs and valves unless the valves are good, doubt it though. 30deg back-cuts on the valves for maximum love. Wonder if he hand laps? :hmm:

NEED TO ORDER:
• ARP Headbolts for the Supra. Need to hunt down the part number
• Order and apply the Second Skin Sound Deadener coating for firewall:
Sound Deadener/Sound Barriers
• Timing kit
• Water pump and thermostat along with all hoses I'm sure
• Landtanks oil pump bushing
• S/C fan as spec'd by TRICKY and CDAN
• S/C specific spark plugs, then wires and cap/rotor
• Locktite 518 for the S/C
• Red coolant
•*Oil pressure sender (mine stopped working years ago)

NEED TO DO:
• Check motor mounts for damage
• Power wash the engine bay after engine removal
• Have intake canister and exhaust ceramic coated
• Protection for the EGR Valve area. Mainly this just involves wrapping the wiring harness but man...the thought of bypassing it tugs at my heart strings :crybaby:
• Thinking about adding the block heater into the freeze plug while the engine is out. This is a nice to have not a must have.
• Finally install the new power steering cooler and reservoir along with PHOTOMAN's alternator mod. The alternator I have now needs to get a quick once over.
• Install EGT gauge and boost gauge. I bought a set of exhaust manifolds that are already tapped for the sensors.
• Make a new home for the VSV
• Install the oil catch can finally
• Send the blower to Magnuson to get the once over. They are in Ventura so its a quick trip

The Cometic listing:
Cometic.png
 
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Higher compression will make more torque/give better volumetric efficiency. But you risk knock or pre-ignition, especially under boost, without good engine management or intercooling. There are so many factors (boost, ignition, intake temps, fuel quality, safety margin, etc..) to consider that I would find a good engine tuner and work out these details based on your goals. Short answer: stay around 9:1 comp. ratio.

Cometic makes very good gaskets. Your gasket choice should correspond with the final comp. ratio you want.

You should gain some power with a bored-out throttle body, but the gains might not be worth the expense - there may be another bottleneck in your system that is holding things back. I have no direct knowledge about the 80 series intake so maybe someone else can give info about oversized throttle bodies. Just like your Landtank MAF, this will just open up the intake tract. It will not affect A/F ratios.

Painted valve-covers are cool. Especially bright colors. Chuck Norris has flames airbrushed onto his.

Hypatec pistons are a brand. The technology is called hypereutectic metal alloy. This means it has more than 11% or more silicon composition. They are much cheaper than forged pistons but not as strong. You might not need the strength of forged pistons depending on your power goals.

The Walbro intank pump is a great option. Its inexpensive and it flows plenty for the SC. There was a thread around here recently where someone found a walbro kit that was a drop in replacement for our trucks, I wish i could remember which one.

I believe WRX injectors are 380cc and they are easy to find for cheap. All depends on your power goals.

Cylinder head work can be pricey but you can gain a lot of power with forced induction. How fast you want to go?

I mentioned water/methanol injection in your other thread and I hope you seriously consider it. You get a cooler intake charge without the need for a physical intercooler, slightly higher comp. ratio, and you can run more aggressive timing. The kits made by Snow performance have safeguards and all the hardware needed in kits that are very inexpensive for the gains you get.

Should be a pretty fun truck once its done. Good luck!
 
Wow, you have been doing a bit of reading. ;)

Here are a few of my $0.02 of random thoughts on the project for what they are worth.

ENGINE BORE - There is a point in getting CU-IN from over-boring, but sometimes can be at the sacrifice of longevity, heat, etc. In most cases I would just bore enough to get a perfect-round set of cylinders and not go too far chasing volume.

COMPRESSION - I would opt for something in the sub-9:1 arena. In a similar setup with S/C on Audis (I have one), the optimal compression has been 8.7:1. Those who have done that change have also gone with forged pistons and can safely run 12+ PSI with a smaller pulley on their charges. Yes, a different motor, but the same essential theories should apply.

HEADGASKET - Good choice if you are going with higher boost.

THROTTLE BODY - Worth asking a few tuners what sort of improved flow vs. the cost of boring.

VALVE COVER - I just rattle-canned mine with high temp paint. Holding up pretty well, and much cheaper than powder coating. Anodizing would definitely be a different touch, and could be pretty nice.

PISTONS/RODS - Pistons, forged if you are planning on high boost. I can not recall anyone who was having problems with the con-rods since these are tractor engines. IMHO anything 450 HP or less they should be fine, and IIRC some guys in OZ pushed twice that with stock rods.

FUEL PUMP - Supra is a direct drop-in as you noted. Should provide more than enough flow.

INJECTORS - Worth discussing how much extra flow you will need based on all the other mods, and if the duty cycle of the OEM ones are getting too close to their max and potentially leaning-out the mixture.

CYLINDER HEAD - Again, be careful not to go overboard and grind too close to water jackets or oil galleys. Some basic port matching and cleaning up the intake runners and manifold should give you plenty of improvements. Has anyone else posted much on this subject?

BLOCK PREP - I would be sure that the shop does not boil / hot-tank the block, thus you would not need to replace the unobtanium oil pump bushing (from LandTank).

Your list of to order and to do will grow, but you definitely have a good starting point. I too have been down the path of "while in there" when getting my motor back together. The project is going to be a great one to watch, and definitely subscribed here.

:cheers:

Steve
 
Block heater? Just curious about this one. I have nothing else to contribute but I do enjoy and appreciate following your threads and the thoroughness you are putting into this and your other builds.

Also curious if there is a heavy duty style torque converter that may be beneficial "while your in there." I know I upgraded the converter in my chevy while the transmission was being built to a heavy duty unit.
 
Higher compression will make more torque/give better volumetric efficiency. But you risk knock or pre-ignition, especially under boost, without good engine management or intercooling. There are so many factors (boost, ignition, intake temps, fuel quality, safety margin, etc..) to consider that I would find a good engine tuner and work out these details based on your goals. Short answer: stay around 9:1 comp. ratio.

I won't really have time to hunt down a tuner and then start that whole conversation I think until after its all said and done. I am hoping someone on the board will have some solid opinions/information to get me started, Of course if there is a good local tuner then I am all ears.

You should gain some power with a bored-out throttle body, but the gains might not be worth the expense

When I did it last time I don't think it was all that expensive. All they did was clean it up, bore the throat and install a new butterfly. I reached out to RC Engineering who did it last time so I will see what they say.

Hypatec pistons are a brand. The technology is called hypereutectic metal alloy. This means it has more than 11% or more silicon composition. They are much cheaper than forged pistons but not as strong. You might not need the strength of forged pistons depending on your power goals.

I'm not a race car driver. I just want the power to be there when I need it and I don't want any lean out conditions where I could blow crap up. I have to do more research on pistons.

The Walbro intank pump is a great option. Its inexpensive and it flows plenty for the SC. There was a thread around here recently where someone found a walbro kit that was a drop in replacement for our trucks, I wish i could remember which one.

That would be awesome. Drop in is key.

Cylinder head work can be pricey but you can gain a lot of power with forced induction. How fast you want to go?

Fast enough to remain reliable. I'd like to keep it just under "stupid"

I mentioned water/methanol injection in your other thread and I hope you seriously consider it. You get a cooler intake charge without the need for a physical intercooler, slightly higher comp. ratio, and you can run more aggressive timing. The kits made by Snow performance have safeguards and all the hardware needed in kits that are very inexpensive for the gains you get.

I don't see me going the Intercooler route because I just don't that have kind of time to try and homebrew up something, which everything has been up til now. I'm looking to LANDTANK to make something cool :flipoff2:
 
Block heater? Just curious about this one. I have nothing else to contribute but I do enjoy and appreciate following your threads and the thoroughness you are putting into this and your other builds.

Also curious if there is a heavy duty style torque converter that may be beneficial "while your in there." I know I upgraded the converter in my chevy while the transmission was being built to a heavy duty unit.

Thanks GRIZZLY. The block heater is really for future use. We don't have our place in Mammoth anymore so that reason is out but I may be doing extended productions in Canada next winter so I just want to be prepared. Just easier to do now.

so true, but only toyota racing red... :grinpimp:


THAT is what I am talking about! :cheers::cheers::cheers:
 
ENGINE BORE - There is a point in getting CU-IN from over-boring, but sometimes can be at the sacrifice of longevity, heat, etc. In most cases I would just bore enough to get a perfect-round set of cylinders and not go too far chasing volume.

The cylinder walls are really thick. Not sure about longevity but I could see heat somewhat being affected.

VALVE COVER - I just rattle-canned mine with high temp paint. Holding up pretty well, and much cheaper than powder coating. Anodizing would definitely be a different touch, and could be pretty nice.

Thinking about this. I could also get a teflon impregnated anodize finish as well. Of course if I don't like it I could always get it stripped and redone. I may just do it to be different. Although after seeing JO MAMA's I'm thinking powercoat may be the way to go. Hmm maybe I can buy one from someone parting their truck and I can do a test first. :hmm:

PISTONS/RODS - Pistons, forged if you are planning on high boost. I can not recall anyone who was having problems with the con-rods since these are tractor engines. IMHO anything 450 HP or less they should be fine, and IIRC some guys in OZ pushed twice that with stock rods.

Agreed

CYLINDER HEAD - Again, be careful not to go overboard and grind too close to water jackets or oil galleys. Some basic port matching and cleaning up the intake runners and manifold should give you plenty of improvements. Has anyone else posted much on this subject?

I've never see it discussed. I would strictly keep it to port matching. Not looking to remove a ton of material.

BLOCK PREP - I would be sure that the shop does not boil / hot-tank the block, thus you would not need to replace the unobtanium oil pump bushing (from LandTank).

I will discuss with Martin. I will get that bushing regardless.
 
I'm a bit confused. What exactly are you trying to achieve? From what I can tell you're just having fun rebuilding the engine, with no set goals. Nothing wrong with that at all, we're very interested in what you learn. One thing to keep in mind, the more variables you change the harder it will be to know what things were positive and which things weren't.

If you want more power, just add more boost. If I were you I'd concentrate on making the engine as bulletproof as possible. Areas I'd look at are fuel delivery...making sure you don't run a lean condition. And ensuring the cooling system is up to snuff, etc...
 
Toyota only supplies 1mm over larger pistons and rings. That's it from their end.

Good luck. This will be a cool (and very expensive) project.

:cheers:
 
I'm a bit confused. What exactly are you trying to achieve? From what I can tell you're just having fun rebuilding the engine, with no set goals. Nothing wrong with that at all, we're very interested in what you learn. One thing to keep in mind, the more variables you change the harder it will be to know what things were positive and which things weren't.

To be honest this is going to be my only opportunity to ever do this again. And I'm looking at it as a good thing not a bad thing.

Do I have set goals? Of course not. Like you said, I want to have fun with it. I don't want a quarter mile tractor. Just a few things to do to it that I've always wanted to do. I'm not going turbo for serious HP. I'm not going the stroker kit for the huge $$$. I'm just having fun. Some things I could be talked out of, specifically those items that are not crucial or wind up taking too long to complete.
 
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Toyota only supplies 1mm over larger pistons and rings. That's it from their end.

Good luck. This will be a cool (and very expensive) project.

:cheers:

At the end of the day this may be the route I go. I have yet to do any research on the piston issue. If i can keep the total for both trucks (putting a low mileage 2F into my 60 in two weeks) under $10k then I would be happy.
 
To be honest this is going to be my only opportunity to ever do this again. And I'm looking at it as a good thing not a bad thing.

Do I have set goals? Of course not. Like you said, I want to have fun with it. I don't want a quarter mile tractor. Just a few things to do to it that I've always wanted to do. I'm not going turbo for serious HP. I'm not going the stroker kit for the huge $$$. I'm just having fun. Some things I could be talked of, specifically those items that are not crucial or wind up taking too long to complete.

Nothing wrong with that. I just wanted to ensure that you've asked yourself some questions before questing. :)

Regardless, I like your writing style and look forward to this adventure.
 
Definitely go with ARP head studs. I fitted Hypatec pistons to mine and have not had any issues even with over 300RWKW. However, if I had my time again, I would pay the extra and fit forged pistons - if nothing else but for greater piece of mind. Having said that, I know there are many boosted engines running huge boost and even larger HP with nothing more that Hypatec's inside. It really is all in the tuning.

I had a Walbro fuel pump and it failed within 5000km. Upon further investigation, when you speak to those who build real engines, Walbro are a poor choice of fuel pump when there are much better pumps available for similar cost. I now have a Bosch 023 in tank. It makes the Walbro pump look like an asthmatic sucking air through a straw. Not to mention is is so much quieter. I also fitted bigger injectors. Most you you guys in the USA seem to be able to get away with the OEM units. However, since the fuel system, or lack of a decnt one, is what will most likely contribute to engine failure if there is one, it's good practice / insurance to fit larger injectors.

I've not done any work to my throttle body. They are far superior to anything on a 4skinner (4runner) and it's blasphemous to do otherwise HAHA!!!

I have 1mm o/s pistons, Cometic HG and a static comp of 8.3:1 There is no lag what so ever and now, the old girl really hitches her skirt when I press the GO pedal.:steer:

Maybe check out my engine rebuild thread in my sig below for more details.
 
Sounds like a good project, but also one to best set some targets so that you get the maximum benefit from it. The TRD SC barely makes enough air to feed the stock 4.5L at 8psi, when running the numbers of the SC MAPs, a M112 is a better fitment. So, that backs up to gains vs 'improvements' on your motor build.

Bore: I agree only enough to be true. 1mm usually does that just fine, and stock toyota pistons are fine for 8psi. Have your shop do a bore report using a bore guage. Many times re-machining the crosshatch is fine.

Coatings: Over rated IMO/E. I have fully Swain coated 26psi turbo engines with no real difference in measured dyno runs or isolated heat management gains. Interesting to note, Porsche factory inline turbo engines coat the exhaust runner in the head with ceramic, nothing else.. IME External exhaust downpipe coating is good for reducing underhood heat, internal coatings don't really do anything.

Head Studs: I'm not a fan of them as a rule. My theory on my machine builds is, if the head gasket 'wants' to blow, let it. I think of headgaskets as fuses for something wrong in the system. Again at 8psi, the head isn't lifting off the block. I had 180k on my engine (66k of that with SC) before the original head gasket showed signs of leaking #6. I never attributed that issue to the head fasteners either.

Compression: Unless you have the ability to tune the software, I see no reason to change the stock compression. Same with forged pistons and rod upgrades. Bone stock will handle any boost the M90 can put out on a cold day.

Throttle body bores: I installed them for years because I was told to. I have yet to see any gain on a dyno isolated to throttle body bore on a low boost system. Waste of money IMO

Injectors. Before you do anything, take the built motor over to a dyno with a WB02, and make sure you are lean first. As others have said and measured, up to 10psi, US trucks dump fuel at WOT.

Fuel Pump. For the SC, the stocker is fine, the Walbro is an improvement, and more than enough for low boost. I use a lot of Bosch application pumps - many of them, but not on the 80, I see no need. (FYI guzzla, to really get an improvement out of the 023, remove the screen and install a pickup basket in the tank. Audi had a TSB on removing that screen over 10 years ago. The 023 is a good 'feeder' pump to the 044 Motorsport, but changing to larger feed lines is needed)

I like the block heater idea!

All IMO/IME and my .02

Scott J
94 FZJ80 Supercharged
 
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Congratulations - It's getting done.

I have nothing to add since I don't know squat about 80s, other than whatever you need to order, ask Martin first. With the 2F, I made the mistake of sourcing some stuff on my own then found out he could get it much cheaper; business to business discount, I suppose. Plus, he gets to make a little $ on it...

You picked the right guy - He'll call you even to verify a different kind of washer !

Good luck!
 
Maybe check out my engine rebuild thread in my sig below for more details.

I have to laugh. It was your rebuild that I originally took notes on way back when you did it. So most of what I posted up is actually from your thread. Sprinkled in with a few other tidbits of knowledge.

I will be discussing the motor with Martin Davidson tomorrow to get a better feel on the direction.
 
Sounds like a good project, but also one to best set some targets so that you get the maximum benefit from it. The TRD SC barely makes enough air to feed the stock 4.5L at 8psi, when running the numbers of the SC MAPs, a M112 is a better fitment. So, that backs up to gains vs 'improvements' on your motor build.

There is a size difference between the M90 and M112 and I wouldn't even know where to begin. For the subject of my build the M112 isn't even an option but for those looking for more info of the M90 vs the M112, here ya go: http://www.lextreme.com/m112.html

Bore: I agree only enough to be true. 1mm usually does that just fine, and stock toyota pistons are fine for 8psi. Have your shop do a bore report using a bore guage. Many times re-machining the crosshatch is fine.

Agreed but just cross-hatching isn't enough to get the compression lowered. I could go thicker with the gasket but thats not always the way to go. With 300k on my block who knows where its going to end up?

Coatings: Over rated IMO/E. I have fully Swain coated 26psi turbo engines with no real difference in measured dyno runs or isolated heat management gains. Interesting to note, Porsche factory inline turbo engines coat the exhaust runner in the head with ceramic, nothing else.. IME External exhaust downpipe coating is good for reducing underhood heat, internal coatings don't really do anything.

I'm going to do this for two reasons only:
• Lower the intake temps from the air filter canister. Heat gain benefits have already been documented here by using various types of coverings.
• Lower the underhood temperature by coating the exhaust manifold.

Head Studs: I'm not a fan of them as a rule. My theory on my machine builds is, if the head gasket 'wants' to blow, let it. I think of headgaskets as fuses for something wrong in the system. Again at 8psi, the head isn't lifting off the block. I had 180k on my engine (66k of that with SC) before the original head gasket showed signs of leaking #6. I never attributed that issue to the head fasteners either.

I've seen my fair share of head bolts snap. ARPs give me state of mind. OE headgaskets didn't fail because they acted as fuses, they failed because it was a bad design. But I get your point.

Compression: Unless you have the ability to tune the software, I see no reason to change the stock compression. Same with forged pistons and rod upgrades. Bone stock will handle any boost the M90 can put out on a cold day.

Bone stock is boring and not the direction I want to go in. IF I do go that direction it will be because time is a factor. Going above stock gives me the option to boost my HP if I so choose at a later date without major surgery.

Throttle body bores: I installed them for years because I was told to. I have yet to see any gain on a dyno isolated to throttle body bore on a low boost system. Waste of money IMO

On the 4.5 this very well may be the case. BUT I will know the price for it tomorrow and will determine then.

Injectors. Before you do anything, take the built motor over to a dyno with a WB02, and make sure you are lean first. As others have said and measured, up to 10psi, US trucks dump fuel at WOT.

If I can find a local tuner I will do this.

Thanks Scott, I was actually hoping you would throw in your pocket change. although you may have dissenters here I do like to hear the opposing view when doing projects like this.
 
Congratulations - It's getting done.

I have nothing to add since I don't know squat about 80s, other than whatever you need to order, ask Martin first. With the 2F, I made the mistake of sourcing some stuff on my own then found out he could get it much cheaper; business to business discount, I suppose. Plus, he gets to make a little $ on it...

You picked the right guy - He'll call you even to verify a different kind of washer !

Good luck!

Yeah I will be having a long conversation with him tomorrow. Thanks SPIKE
 

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