1UZ Flywheel particulars for RX8 gearbox

[Biggles_me]

Hi guys, Never been here before, but I now own a 1UZ on a pallet and I hear you guys know your stuff! I have done a search but couldn't find an answer to this specific question.

Said 1UZ is going in an MX5, with an RX8 gearbox. I know that might seem strange, but I'm doing this as cheaply as possible, and an RX8 gearbox is a hundred quid in the UK. Even if it was a different box my question would stand.

I'm not an expert, this is a general question as well as a 1UZ question. I gather there are a couple of different Toyota flywheels that can be made to fit the 1UZ, but what do I do about a clutch? I'm imagining you need to use a pressure plate for that particular flywheel, but then a clutch disc that will fit that pressure plate and have the splines for my gearbox? and as for clutch height, would that be handled by the thickness of the adapter plate?

There is a company in Poland who make a flywheel specifically for a 1UZ to RX8 gearbox but it's quite expensive, and as I said this is to be as cheap as possible, I'm making pretty much everything else myself. The flywheel they sell puts the contact surface quite a distance away from the ring gear, which makes me wonder how on earth you would do it without buying a special flywheel.

I know that BMW boxes are popular for bolting to 1UZs, but without buying a special flywheel, how are you supposed to get a clutch to work, and how do you figure out what that clutch is so I can apply the same technique to my RX8 box?

 

[gloverman]

Simple stuff. Find suitable flywheel , use pressure plate which bolts to the flywheel which has enough clamp to hold up to 1uz engine , use centre disc which has correct surface area and diameter to suit the pressure plate / flywheel combo and the same splines as the gearbox. Also check the springs don't foul on the inside of the pressure plate. Then use a suitable clutch release / engagement mechanism. The last MX5 I worked on solved this issue by being auto. haha. If I'm doing something different ot normal then I generally get out my measuring gear and work out a combo that works however often if someone makes the parts already buying a proven setup if very cost effective. I can't imagine much out of Poland being cost prohibitive.

 

[Biggles_me]

Haha you'd think so, but the flywheel is 400 euros and after spending 600 quid on an engine, a clutch a gearbox and then a flywheel really isn't in my budget.

I figured that might be the answer, is the box input shaft length not usually an issue? I take it that video is something you worked on, did you use the RX8 box? If so can I ask what parts you used to get it together?

 

[gloverman]

That RX8 is one I was called in to fix after it was built as a 4.6 and didnt go as it should. Turns out stock small injectors cant feed a 4.6 at 7500rpm safely and melts pistons. I was phoned after it blew up and I knew of parts to sort then added knowledge. Its running a 5 speed mazda box with tilton twin plate clutch. Bottom end is stock gen 1 with stronger rod bolts, ported heads, kelford cams , 540cc injectors and motec m800 ecu. Custom headers and massive exhaust. Custom radiator. The owner has two sets of itb's to choose from when hes ready to fit those. I supplied the high flow pump for the tank too then sorted issues and tuned. The canbus and motec didnt co-operate.

If you look at the rest of my channel its nearly all uz jobs.

Its important to confirm gearbox input shaft length too. I always check spigot penetration on different jobs if using different parts. And then i double check it. I have my own flywheel and clutch setup which I try to use along with my own designed internal release bearing setup.

Adaptors can also alter distance so thats important to check. Back when using crappy MR2 flywheel we were making custom release bearing carriers to prevent the release bearing falling off the sliding surface. A proper flywheel solved this by being thicker.

I have a customer in Poland that Im helping with a turbo UCF20 LS400.

 

[Biggles_me]

Well I was thinking of using the MR2 flywheel as I'm told you just need to alter the crank bolt PCD and bevel the ring gear, then a pressure plate from MR2 and clutch disc for the RX8 box, except finding individual clutch parts that can take up to 300ft/lbs isn't easy.

I'm gonna make my own gearbox adapter plate cause fabrication is nothing new to me. So spigot penetration can be handled there. It's just finding the clutch parts that could be an issue, as well as the clutch fork on the RX8 box.