New Crank/Rod Idea (4.8L)

[rarson]

Yeah, I knew that a lot of Hondas had less than "optimal" R/S ratio, a fact that a lot of people don't seem to realize. I think I wouldn't want to go too thin on the rod journal size, so with 48mm, I think a 150mm rod will be the longest rod I'd be able to easily fit without decreasing stroke.

Wait, no, I just had a thought. Magnus Motorsports sells identical rods to the 4g63, except you can get them in 156mm or 162mm. I'm not sure if they sell Eagles of that length, but I think the Eagles would be the best choice for a good rod that will handle power. The only bad thing is the Eagles aren't the lightest in the world.

We'd have to move the offset down all the way, 4mm, and then the wrist pin up 5mm to fit the 156mm rods. I don't know if that is possible or not. I think 150mm is the ideal length.

How exactly did you find these rods? I guess I just don't understand what you mean by Honda style Chevy rods. I'm going to look for a set on ebay, if I can find 8 of them for $200, sold.

Edit: Wow, nevermind. I just did a search for "nascar rods" on ebay. I had no idea these things were out there! Thank you!

 

[rarson]

Okay guys, I screwed up. The rod journal size that I have been quoting for the 4g63 rods is actually the rod bore size. Which means the rod journal size is another 3mm smaller. I realized this when I was looking at some aftermarket rods.

This means we're actually grinding 7mm off the rod journals, which means more weight reduction and more flexibility for whatever rod/stroke combination we want. This means we lose more weight off the crank and our max stroke with the stock crank goes up to 96.5mm. This gives us a quite incredible 4.6L with the stock 1UZ bore! R/S ratio takes a dive to 1.55.

If we wanted to use the stock pistons, and move the rod in 3mm, we still get 4.5L and a 1.60 R/S. Or, we could go further still, and use a 90.5mm and use a 156mm rod to get over 1.7 R/S ratio and get 4.35L. The 156mm rods will be more expensive to use though because I am unaware of anyone besides Magnus that sells them.

I've found a set of Scat H-beam rods for $280 on ebay. That's only four but they are good rods. I do not know the weight of these. Eagle H-beams are 550 grams and are all over the place for $295-$300. So I know it's not as cheap as some other rods out there, but I think this is clearly the best choice of rod for the person wanting to get the max stroke with the stock crank, especially if they want to use the stock wrist pin.

I will warn anyone thinking of doing this, make sure you buy the "7-bolt" version of the rods. These right out of the box are .1" thinner than the 6-bolts which means less to machine, and also have the 22mm wrist pin as opposed to the 21mm pin of the 6-bolts. Eagles are the easiest to find on ebay in the 7-bolt form (many rod manufacturers don't even make a 7-bolt version).

Just for shits and giggles, if we take a 3UZ and use these rods with the max stroke and a .040" overbore, we get... 5.12L. With the stock crank!

Another idea might be to use a 2UZ crank. We could get even more stroke than this but I personally wouldn't go over 96.5. Just for reference, 4g63 guys build stroker motors with the stock rods. That's 100mm stroke with a 150mm rod (the stroke makes it real easy to calculate R/S ratio ). Those engines work well up to a little over 8000 rpm. The guys using 156mm rods (not much of an improvement in R/S ratio) run theirs up to 8500 rpm. So as 928S said, get the tolerances right and you can run a lower ratio.

I'm having a hard time trying to decide whether I want the torquier, higher displacement of the full 96.5mm stroke or the higher-revving, lower displacement of something like 93.5mm or 90.5mm.

 

[rarson]

The max serviceable limit of these cylinder bores is .060". If we're staying N/A, I say we go all out and do .060" over, which is an 89mm bore. With a stroke of 96.5mm, we get a displacement of 4.7L, with a 1UZ block.

WITH THE STOCK CRANK!

I almost feel like this engine would be much more fun to drive every day than the higher-revving idea. If one wanted to use the stock pistons by moving the stroke in 3mm, we'd still get a displacement of 4.65L with the 1.6 R/S ratio. I really want to move the wrist pin up though, and make the piston even lighter. Also, don't discount the stock '95-'99 rods. I feel these are perfectly up to the task and you should be able to get them for at least half the money of the Eagles (I just got a set of 8 for $175, check the DSM boards). My car has 60k miles on it, and has been pushing 380 hp (flywheel) for about the last 15k of that, on those stock rods. I think anything above ~875-900 hp would be pushing it with these rods.

They also typically look great even when used.

 

[rarson]

Not to cross-post info, but my choice will be 93.5mm stroke. That way, I can use the stock pistons and try it out. With the 1UZ, I will be looking at about 4.55L. Then, in the future, I'd like to get the wet sleeves and 156mm upgraded rods and make a 6.0L, with a 1.67 R/S ratio.

 

[rarson]

Okay, quick note, brain fart again. The 156mm rod is 6mm longer, so moving the wrist pin up 3mm will not work (duh). I think with ring alterations, we may be able to get the pin up 6mm. They will look like 928S' pistons.

 

[turboandrew]

I have wondered if there was a way to resleeve a block to have an integral "deck". Basically, mill out the old sleeves and go further to the point where the bores are siameesed, kind of like what one would do with the darton sleeves. Then, for each bank, use four new liners, but also install what I can best describe as a honing plate of a desired thickness. The new liners would stick out the original block the same distance as the thickness of the honing plate. The new liners and the honing plate would be welded together while all components were in the block. The the combined part is "decked", then bored and honed. What you end up with is a aluminum block with siameesed iron bores with an intergral iron deck. The only other thing I think you would need are the coolant holes and a good way to seal coolant between the new deck and the block (head gasket goes between deck and head. OK, why do all this? Increasing the deck height could get you a lot better r/s ratio -and- you could use longer, more widly available rods like the H-beam, (small journal for offset grind), 6" c-to-c rods that seem to always be for sale on ebay.

So, let's say you go with:

98mm sleeves and a 82.5 stock stroke = 5.0l
98mm sleeves and 96.5 mm stroke = 5.8l
98mm sleeves and 98mm stroke = 5.9l

personally I like the stock stroke and 98mm bore. Use a 6.0" c-to-c rod and a 6.4mm thick integrated deck. You keep the recirocating mass way down, and get an incredible 1.82 r/s ratio and you still have lots of displacement. 8500 rpm redline all day

 

[rarson]

I am a little worried about adequate cylinder filling with such an oversquare engine. I may have no idea what I'm talking about, but what I mean is that you have to fill a much larger space with the same amount of "time" (stroke). Now granted, with 1.82 R/S ratio, you've got less dwell and slower piston acceleration, but I still think it might not be enough stroke to fill the cylinders all the way to the bore.

I am looking for an undersquare solution with a good R/S ratio, however, I think that's a bit of overkill because I'm sure that we don't need 1.82 ratio to rev to 8500 rpm. With that ratio, I think you'd be good to 9500 rpm easy, but I'd have to do some calculations to be sure.

What I am looking to do is use these stock 4g63 rods that I have, with the stock pistons. I am sure of the rod journal and pin journal sizes, and rod thicknesses and the length of the 4g63 rod. What I am unsure of is the length of the 1UZ rod. The reason is there are a lot of different threads with different numbers which lead me to believe it's somewhere around 146-147mm. So with this stock parts combination, the 1UZ rod length will determine my stroke (92.5-93.5mm).

I also would like to be able to use a longer rod in the future, as an upgrade. I was thinking this would be impossible until I realized that if we moved the rings up at least another 2 mm, we could move the pin up 6mm. That would allow us to use the 156mm rods which are otherwise identical to the 6-bolt rods, and are rated to over 800 hp (for a set of four). We'd have to grind a little more off these rods and use a 21mm pin instead of the 22, but I was only interested in using the 22mm pin to fit the stock rods. Even with a 93.5mm stroke, that gives us a 1.67 R/S ratio, as opposed to the 1.60 of the 150mm rod combination. Plus we will be losing a lot more weight off the piston.

Basically my plan is to build the engine in 2 stages. The first stage will use the modified stock 4g63 rods and an offset-ground crank for the bottom end. I will be modifying the top end as well with ITB's and such. I'd like to see how far we can push this "nearly stock" bottom end, naturally aspirated. Stage two would involve tearing down the block, putting a new sleeve system in for a bigger bore, and upgrading the rods and pistons. I'm not even set on what I'm using for this step yet. If I want to go twin-turbo, I'll use 150mm rods and space the rings a little better, with a stock-height wrist pin. If I want to stay naturally-aspirated, I will use the 156mm rod and move the rings up to make the lightest piston possible.

The nice thing is the engine can go either way even after stage 1. I haven't done anything that can't be undone without a set of custom pistons, which are an eventuality anyway (even the ITB's I plan on using if I go with FI).

Now as far as 1UZ vs. 3UZ is concerned, I'm very much leaning towards the 3UZ. For one, we'll get more displacement and obviously more power with the stage 1 setup. For two, the 3UZ has larger valves than the 1UZ, meaning if I oversize them I can go even larger. Thirdly, the 3UZ has VVTi which I wouldn't go to extra trouble to find on a 1UZ, because I'd rather get the 1UZ for the value of it... in other words, if I'm buying the 1UZ, I might as well save money. But I'd like to try using it and get some custom regrinds. The biggest reason I like the 3UZ better is the design of the factory pistons. They're coated, the top ring is closer to the crown, and the pistons have quench pads. These look ten times better than the 1UZ pistons (and it looks like they won't weigh much more, if any, than the 1UZ pistons because it looks like Toyota took a little weight out of the design). Definitely a better piston to start with if we want to see how far the stock hardware can take us.

Now cams may be an area where too much overlap in our N/A engine won't be good for the FI stage. But I am curious whether or not we can simply turn one of the cams a scissor tooth off to adjust the overlap?

So conservatively using the 92.5mm stroke and stock bore size, we get 4.45L for the 1UZ and 4.81L for the 3UZ. Either engine can accept the same sleeves, so stepping up to the 98mm sleeves would give us 5.58L. I like this. The great thing is this gives us a cheap way to upgrade our engines while we save up for the pricey sleeves, pistons, and rods.

I have been trying to find a source for 3UZ engines but I have been unable to find any. I should probably ask around on island because there has to be at least 1 sitting somewhere, but if not, I'll have to buy online and have it shipped.

Since I am on lunch break, I don't have the time to do so right now, but later I'll calculate the compression ratio of the stage 1 engines to make sure that we aren't going too high.

 

[rarson]

Andrew, I forgot to address this, but I think what you're talking about is an extended deck? I know a few companies make both blocks and adapters to increase the deck height on some Honda engines. So it's possible, but I'm sure you wouldn't find any for the UZ-FE. A custom one would probably be more money than it's worth for the gain (and I don't think they work too well for FI applications).

 

[turboandrew]

Yes, extended deck. You might have a really hard time finding a 3UZ. I have a 1UZvvti (1998) and I have not come across another, but I see early 1UZ motors all the time. After considering all of this, I think I will stick to my original plan: use my 2UZ to get all my conversion issues worked out, then build up a 1998 1UZvvti with proper aftermarket pistons 020" over 9:1 compression, stock crank, early 1UZ rods, and top off with whipple/lysholm 2300 supercharger. I think 500-600 rwhp is doable with stock cams and 15psi. Ok, closer to 500 rwhp to 600, but in a 3200 lbs car it should be on the edge of street tractability and a lot of fun.

 

[rarson]

Yeah, I can find early 1UZ's pretty easy.

If someone were looking for the best R/S ratio, a 162mm rod is available from Magnus as well. If we're keeping the stock 82.5 stroke (which would require the pin to move 2mm up) we'd get 1.96. That's a bit high I think. A better choice would be the 162mm rod with an 86.5mm stroke. Even that is 1.87 though. I really don't think we need sky-high R/S ratios to rev well, especially if we're only revving to 8000 rpm. I think the ideal R/S ratio for a naturally-aspirated setup would be the 92.5mm stroke with 156mm rod, wrist pin moved up 6mm, giving a R/S ratio of 1.69. For forced induction, we can keep the 150mm rod and the meat on the piston and still get a 1.60 R/S ratio.

I will probably have to go with a 1UZ, which I don't mind, but I'm not very thrilled about trying these stock pistons out. I'm actually thinking of maybe not using the stock pistons and just bore it out to 89mm. Then I could get 4.6L. If I wanted to sleeve it later then I could. But then again, if I'm getting new pistons at this point, I might as well move the pin up and get even more displacement.

Sheesh, decisions decisions! Can anyone give me the accurate, end-all-be-all rod length for the stock 1UZ rod?

 

[rarson]

Okay. I think I have decided the route I'm going to take. I've been watching and listening to that video of the 1UZ revving with the ITB's, over and over again, and I love the sound. I'm afraid if we add too much displacement that it'll take away from the character of the 1UZ, specifically it's sound. I think I'd rather be able to rev the engine faster than to punch it out with the maximum bore and stroke.

With that in mind, I want to be able to maximize the material removed from both the crank and the pistons. The only way to do this (with our 45mm rod journal size) is to use a longer rod. My choice of rod would have to be light, strong, and already available. The rod I am choosing is the 162mm Magnus Motorsports rod.

I still have to email Magnus to see how much they are and what brand (though I'm pretty sure they are Pauter) and hopefully, I would say probably, they can do the machining to the big end before shipping them out. I am expecting these rods to cost at least $1400, due to the fact that they are Pauter and they are not the most common size.

In order to use these rods, I want to use an 86.5mm stroke. This means we still have to push the pin up 6mm. After studying the piston pictures and looking at the numbers a bit, it seems that we should be able to do this if we move the rings up and closer together, which is another thing I wanted to do anyway. The pistons will likely be Ross custom, since they already have the 1UZ piston design, I'll just ask them to make some modifications to my specs (which I know they will do, but probably at extra cost).

The block will be bored to the max. With an 89mm bore and an 86.5mm stroke, we'll get 4.3L. With the 162mm rods, we'll accomplish this with a 1.87 rod/stroke ratio. This engine will surely rev higher than a stock 1UZ easily!

Now, high revs will also surely require some modifications to the upper half of the motor. So with this final decision in construction of the bottom end, I am beginning to consider other necessary upgrades. Specifically, I think we may need to convert to solid lifter setup, which may be possible by adapting an existing Supra conversion, if such a thing exists.

The thing I'm concerned with, really, is the high valve acceleration of aggressive cams combined with the high rpms. Naturally, valve float will be less of a problem if we use stronger springs and solid lifters. But, stronger valve springs is akin to adding rotational weight. It's that much harder to turn the cams. Valvetrain mass reduction is something I'm certainly looking to do, and that will include lightweight valves and retainers. I think the key for high rpms is going to be making three things work best in concert with each other: cams, lifters, and valve springs. I think if we balance these things, we will have a set of heads that will happily rev to 10k or more.

I certainly would like to hear a 1UZ rev to 10k, what about you guys?

 

[turboandrew]

If you are going to use Pauter, I think they already make a 2UZ rod, which is exactly the same C-to-C, big end, small end as the 1UZ rod (someone please correct me if I got this wrong). Since Pauter is pretty much a "don't stock, custom build to suit", I bet you can just get whatever you want directly from them with little if any more cost than thier "normal" 2UZ rod.

Can you bore the existing 1UZ to 89mm without new liners?

Not sure what you mean by solid lifters. The 1UZ is a solid bucket/shim design, no cam follower/lifter in there. With a slightly heavier spring it should rev up no problem. Lex has used 2JZGTE springs & retainers. I will eventually figure out what the later 1UZ motors had as far a spring rates. I suspect they are a little higher since (I think) they have a slightly higher redline. Anyway, with better srpings the top end should be no problem. Just get the right cams.

 

[rarson]

Yeah, I realized after I went home on lunch that both the UZ and the 2JZ use a solid lifter setup. I have worked on an RB25DET engine and that uses cam-on-bucket but with hydraulic lifters. The RB26 head uses solid lifters, and thus is harder to adjust lash. No shimming is required with the hydraulic adjusters, but solid lifters can take high revs a lot better than H.L.

The bore of the 1UZ is 87.5mm, and on Lextreme's Tech section there is a page stating that max operational bore is +.060", which is a little more than 1.5mm. Since the bore seems to last pretty long on the UZ anyway, I figure with all-motor I might as well go for it and get the best bore I can. But even if I don't go +.060" I think I'd be happy. I calculate the sleeves to be about 5.1mm thick, so I don't think 1.5mm over should be a problem.

I will try to contact Pauter and see if I can get the rods directly from them. I will still be regrinding the crank and using the smaller rod journal, so that I can get more stroke with less weight on the crank. Is there any problem with using such small rod journals? I mean I know the stock 4g63 crank with this size rod journals has held well over 800 hp, but is there a reason why Toyota used such big journals? If it's a strength issue, that should be less of a problem for me without forced induction. But then again, inertial forces are a large part of the stress so... I don't know.

Thanks for the input. I appreciate any comments, criticisms, or suggestions. You can never get too many angles on an idea.

 

[rarson]

Just a question on the sleeves. The 3UZ sleeves are the same thickness but a bigger bore. So wouldn't they be experiencing a bigger stress from explosive forces? It seems to me that with a smaller bore we'd be able to use a thinner sleeve. If the 3UZ sleeve is also good to +.060", maybe we can push our luck with the 1UZ and do +.080"?

 

[Lextreme II]

Andrew,

I have a VVT-I head at home and i will do some more investigation on it. I the springs and head design is slightly different then the earlier generation. I have the 2JZ springs and they work great. I think they 82 lbs sitting pressure vs. stock is 40 lbs.

 

[JBrady]

Remember the stock sleeve on the 3UZFE is only 1.5mm. NO overbore is acceptable from the factory. I like the other plans. If the Mitsu rod is wider I assume you will have them machined to the proper Lexus journal width?

 

[rarson]

Yeah. If I can order them straight from Pauter for the same price, then I might as well just have them make them with the journal width that I need. But otherwise I'll just get a machine shop to make them thinner.

Are my numbers on the sleeve size of the 1UZ correct? I thought the 3UZ and the 1UZ had the same sleeve thickness?

 

[rarson]

Okay, back to the Nascar rod idea. I can get the bore and R/S ratio that I want with these and they are MUCH cheaper.

Will these rods work? The large end it says is .880", whereas the stock rod is .904", correct? I assume .02" would be off too far.

 

[Lextreme II]

I think they are too long....

 

[rarson]

I know they are longer. The rod journal is smaller so they will fit with an offset crank grind and moving the wrist pin up. I just want to make sure the width is correct. If that is the case then I can get a cheap set of rods that don't have to be modified!