4.7 1uzfe!!!!!!!!

[Spoka8n]

well, my 92 sc400 is hitting the 300k soon and i wanted to refresh the motor and get a little more torque and power out of it. i've been doin my hw and searching around and been reading alot about mating 2uzfe 4.7liter tundra block with the 1uzfe head. i knoe that everything is basically bolt on with the exception of changing oil pickup bolts, get the custom engine mount and get custom pistons.
I'm not looking for extreme power. But more then the stock 1uzfe would be great!

my question is can you use the 2uzfe pistons safely for n/a daily driver? if not are there any other ways to match it with some other pistions beside the Ross setup?

 

[Lextreme II]

You mod the 2uz pistons to mate with 1uz heads. SPF_Lexus did that. Oil pick up pipe? It doesnt need to mod at all. You will also need 2uz/1uz engine mount. We have them for that swap.

 

[Spoka8n]

wow, that sounds really simple..
soory for soundin like such a noob but if i take it to a machine shop and ask them to match the 2uz pistons to work with the 1uz head, would they knoe wat to do? or are there some other details involve?
would the pistons be as reliable after its modified?

sorry about the misswritin sentence about the oil pickup. i meant the bolt has to be redrill from mm to 8mm?

for headgasket wise, would it be better to use the 1uz or the 2uz headgasket?

 

[Lextreme II]

if i take it to a machine shop and ask them to match the 2uz pistons to work with the 1uz head, would they knoe wat to do? or are there some other details involve?

Some do and some dont. We can mod that for you if you send them to us.

would the pistons be as reliable after its modified?

It should. Depending on your application

sorry about the misswritin sentence about the oil pickup. i meant the bolt has to be redrill from mm to 8mm?

Still dont understand what you are referring to

for headgasket wise, would it be better to use the 1uz or the 2uz headgasket?[

What do you think?

 

[Spoka8n]

i'm juz runnin it n/a.

i would say 1uzfe headgasket since we're are using the 1uzfe head, but not 100% sure that why i'm juz trying to get that verified.

so here i've made a list of what i need to make it work. please correct me if im wrong.

-2uzfe block with mod pistons.
-custom motor mount from Lextreme.com
-read your article about driling the 6mm to 8mm for the oil pickup pan bolts.
-and everything from the 1uzfe should bolt up to 2uzfe block juz like juz like stock.

 

[Lextreme II]

i would say 1uzfe headgasket since we're are using the 1uzfe head, but not 100% sure that why i'm juz trying to get that verified.

NO.. you can not use 1uzfe HG. The bore size is different. So it make sense to use bigger bore like 2uzfe because your lower block is 2uzfe. Make sense?

-2uzfe block with mod pistons.

Yes that will work but not the best option. Getting custom pistons would work best

-custom motor mount from Lextreme.com

That is correct

-read your article about driling the 6mm to 8mm for the oil pickup pan bolts.

That is correct.

--and everything from the 1uzfe should bolt up to 2uzfe block juz like juz like stock.

Pretty much...

 

[spf_lexus]

Milling the stock 2uz pistons is definently the cheapest way to get the 4.7 running but if you have the cash, get some Ross 2uz pistons and it will have any compression ratio you want, plus more efficient combustion. I have my 4.7L done, but it hasent been fired up, school halted my project until this May. I only paid $10/piston to have them machined. This lowered the CR to 8.8:1 which is good for boost.. not so good for N/A. Speaking oif N/A, if your planning on keeping it this way your stock ECU/fuel system will handle the block no problem, I test drove David's 1st proto and it was night and day fun over the factory 1uz SC400.

It's really a straightforward swap, I would reccommend getting the heads rebuilt as well. My 200K 1uz had a 40% flow loss from all the miles.

Good luck on the project!

 

[Spoka8n]

"I test drove David's 1st proto and it was night and day fun over the factory 1uz SC400."

Spf Lexus, you make me feel like goin out there ryt now and start rippin things apart!! cant wait till ur project to get done. its insane what you guys do with ur V8s'!!!

yeah, i might juz save up some money and get the ross pistons juz to solve the compression issues. I'm rebuilting the whole long block, since i'm keepin the sc for a very long time. would u guys recomment oversize valves?

40% flow loss? thats insane!
mine has almost 300k, it still drives fine, but the power isnt all that.

 

[spf_lexus]

Oversize valves are not necessary. The stock UZ head will flow quite a bit, actually the lower intake manifold is the only reason why the uz wont make power abover 6k so if anything save the cash if your trying to keep the budget in check. Diving into the UZ heads really requires a dive into the checkbook. To answer your Q tho, yes oversized valves will make more power fo the swap.


The reason why my compression was so low was because my ex-girlfriend owned my LS before I had it and she never EVER changed the oil so I cant blame the engine for not keeping it together .


As for my 4.7L I have been purposefully ignoring it because I have REALLY wanted to drive it and I go to an automotive college and I get asked about it daily (drives me nuts!). School is my priority and i just got a little over my head with my last summer break. It's 100% done mechanically, 50% done electrically so mid summer I should be able to finally show something.

 

[Spoka8n]

Well, wouldnt the other way to take care of the compression issue with the 2uz pistons would be increase the compression by milling the head down more? With the Ross 2uz pistons, what compression ratio would you prefer for this kind of project to be between reliable and safe?

man, i got to give you props for being so patient with ur project..i wouldnt be able to do that.

i used to drive a 92 ls400 passed down from my sister to me. it was the same way, she never took cared of the damn car, juz poped in and drive. although she never really took cared of it, it still drive so smooth and pull pretty damn well. but i eventually sold it and bout a sc4. miss it though.

 

[spf_lexus]

Thanks man yeah it's hard sometimes not to think about it . I suppose milling the head to account for the CR loss is possible, but not the best way to do it. I had to mill my pistons because their "dome" is curved on the 2uz, rather than flat domed like the 1uz poston/head. One thing to consider is when you start milling the heads down your actually throwing off the timing by causing the t-belt to become longer. What happens when the heads become shorter, and in turn the T-belt routing will be come shorter. You will need to modify the timing belt tensioner so it can hold the slack as the OEM unit's "pin" wont be long enough but it's pretty easy. If you just resurface the head you wont have to mess with this, I was on my 3rd when this build started.

I never asked my builder to "ride the edge" as far as CR goes... it may be possible to take less material off the pistons, maybe 9:1 can be done? I suppose a high stall torque convertor would help a little off the line to account for the off CR but you gotta remember the 2uz is going to put down a lot of tq over the 1uz regardless.

 

[cribbj]

Have a read before you start machining:

http://www.lextreme.com/Cam-Timing.html

 

[Thermactor]

It's really a straightforward swap, I would reccommend getting the heads rebuilt as well. My 200K 1uz had a 40% flow loss from all the miles.

Good luck on the project!

What does this mean? That the valve steam seals were gone? Which components specifically had been worn down to cause this flow loss?

 

[spf_lexus]

valve seats/faces were in horrid shape. It was burning some oil, but nothing too crazy. I think it may have gotten hot before I bought it. 3 sisters learned to drive on this LS sdo it's seen some torture in its years. I can verify the flow loss because when I reebuilt the heads it was night and day performance. MPG was back, more response, and smooooooooth.

 

[Spoka8n]

Thanks man yeah it's hard sometimes not to think about it . I suppose milling the head to account for the CR loss is possible, but not the best way to do it. I had to mill my pistons because their "dome" is curved on the 2uz, rather than flat domed like the 1uz poston/head. One thing to consider is when you start milling the heads down your actually throwing off the timing by causing the t-belt to become longer. What happens when the heads become shorter, and in turn the T-belt routing will be come shorter. You will need to modify the timing belt tensioner so it can hold the slack as the OEM unit's "pin" wont be long enough but it's pretty easy. If you just resurface the head you wont have to mess with this, I was on my 3rd when this build started.

I never asked my builder to "ride the edge" as far as CR goes... it may be possible to take less material off the pistons, maybe 9:1 can be done? I suppose a high stall torque convertor would help a little off the line to account for the off CR but you gotta remember the 2uz is going to put down a lot of tq over the 1uz regardless.

guess i'd rather juz go the safer route and not mess with anything else, plus 9:1 compression ratio is lil to low for wat im lookin for especially in my N/A setup. you think detonation occur if it was 11:1 or 12:1 runnign with stock systems? well juz a thought though

 

[stevechumo]

Have a read before you start machining:

http://www.lextreme.com/Cam-Timing.html

I just skimmed through that article and I'd like to share my experience with not keeping the stock height between the bottome block and heads. It's that I use the thicker head gaskets to decrease the CR. This makes the overall height higher. The result is the timing also gets retarded.

 

[spf_lexus]

I think 11:1 could be done on 91 pump gas but you'll need to invest in some kind of piggyback/standalone that can play with timing and fuel. 12:1 would require deeper tuning and almost for sure would require race fuel. Just as an example OEM Integra type-r runs 11:1 on 91 octane.

Steve-

Since your mnore informed regarding piggybacks, would an SAFC work for an N/A high CR?

 

[Spoka8n]

spf_lexus- did they mill of much of the piston at all? and what is the stock compression for 1uzfe by the way?

 

[JBrady]

spf_lexus- did they mill of much of the piston at all? and what is the stock compression for 1uzfe by the way?

90-95 10:1, 95-97 10.4:1, 98+ 10.5:1

Higher compression does yield more potential power but it is not dramatic for 1/2 a point or so and definitely a looser if you have to pull timing and or run too rich.

Detonation threshold is determined by chamber design and efficiency with smaller bores having an all else equal advantage. Minimal surface area, no hot spots, exhaust side bias.

Spark plugs, heat range, fuel delivery, cooling system, metal compositions and more come into play.

The direct injection LS460 runs 11.8:1 on a 94mm bore

 

[spf_lexus]

That direct injected 4.6l is also in a $100,000 car. The tech to run that high of CR isn't cheap unless your driving a honda/nissan.