Gearbox Adaptor Plate questions

[clip14]

Hey guys

So I'm thinking of starting a vh41de swap soon and will most likely be making my own gearbox adaptor plate to mate it up to whatever gearbox i end up using. I am thinking of using a RB gearbox.

So far, this is what i understand about adaptor plate design/manufacture. the adaptor plate has two bolt patterns - one to bolt to the engine, and one to bolt to the gearbox.

either the gearbox bellhousing is machined down to allow for the thickness of the adaptor plate to not interfere with the clutch mechanism, or a spacer is used on the flywheel to account for the thickness of the adaptor plate.

my question here is, how do you ensure that the gearbox and engine line up? (as in how do you ensure that the bolt patterns on the adaptor plate are accurate?)

how accurate does it have to be? can you just trace out a pattern on a peice of paper to line up the bolts on the engine and then the gearbox?

hope I am making some sense!!!any help would be appreciated.

Cheers

[tmorgan4]

Ideally you'd have bolt patterns drawn up for both your engine and transmission with the center where the transmission is marked. Using these center points you can overlay the two drawings and get your plate.

I would assume the two need to be pretty damn close. You'll have a hell of a time getting the transmission and engine to mate up if they aren't, and probably ruin your soft pilot bushing in the process.

[clip14]

yeah it seems that a lot of people make their own adaptor plates, so it would be great if someone who's made an adaptor plate can tell us how they managed to get the required accuracy of their bolt patterns!

Thanks for your reply

what is a soft pilot bushing?

[ultrapulse]

I made a complete new bellhousing, however the same rules would apply I guess. I made a plate that bolted onto the engine, then made one bolted onto the gearbox (yours would be one plate though).Make sure all is quite close but leave one pair of dowels undrilled. Then I removed dowels from gearbox, drilled small pilot hole back through the hole where the dowels sit all the way 'south' (if possible with your box). Then made up sharp dowel replacements that sit just below the surface. Bolt box housing up ABSOLUTELY PERFECTLY so that all shafts turn with no more resistance than usual. Then using small dia rod smack the manufactured dowels from the back by inserting a rod into the small drilled holes. Then using a centre drill be very careful and clamp/drill the holes. Apparently you need to be within a couple of thou. My t56 has tapered rollers on the input shaft so there is NO movement side to side on the spline. Most gearboxes have a high clearance front bearing to allow somew movement, however the less this is the less hassles you will have, and yeah I's say less than say 5 thou if using a c5(?) clearance front bearing.I used a large shaft which I spun up and bolted it in the first and last bearing journal, then through the front housing of my gearbox, which I made up another dolley to sit in its usual bearing housing. Drilling those 2 dowel holes made me very nervous:) Just took my time, did it properly. Once it was all done I refitted it all and may be 1 (prob not 2) thou out as the dolley is slightly firm to turn. I was wrapt! Especially considering I have no special gear and have to weigh up errors and how to keep them low. This may not make sense, but will try to find the link which I think i posted a while back. I know its different to your setup but may give you some ideas. From what I understand with your setup I would make a spacer plate, then a new flywheel with the correct clutch offset, and ring gear location, allowing also any clutch to be used while your there making the flywheel. Afterall flywheels are a relatively cheap and easy made part of the kit, since any NA zed32, auto TTz32 or vh ringgear spun off the flexplate is suitable. Now will try and find that link.Just keep in mind though that getting this adapter plate right takes a bit of precision! along witha bit of strength. You dont want bolts ripping threads out over the first 100mph wallow! Without discrediting engineers out there, I sometimes struggle to get a good precise, or even an ordinary job done properly, hence end up doing it myslef mostly now. Even if it does take twice as long, and has me scratching my head:) Good luck!

[ultrapulse]

no wonder I couldnt find the link under nico:)http://www.300zx.co.nz/phpBB2/...t=t56

[craigztoyz]

THANX ULTRA!!!!!!!!All the pics you have of your ride, I appreciate. Like a Fat chick appreciates a free cake oh did i say that

I'd love to see a few of the underside of your engine/clearances. Thanx for the help

[clip14]

thanks for the detailed reply ultrapulse.

so your advice is to mate up the gearbox to the engine with as much accuracy as possible, then get a custom flywheel made to fit the vh ring gear so that I can use the standard vh starter motor with the clutch of my choice?

[ultrapulse]

On the button. I'd recommend the z32TT clutch, as its factory linings mean grandma driveability (apart from moderately big left leg) and easily got parts. Just dont go aftermarket cheep disc or else you may rip off the linings. Nissan ones are good, but $$.I have a slightly modded z32 which ran a low 13 at just over 170kph (on rubbish Nankangs on an un-prepared track). The clutch has never slipped. Mind you they are factory around 1800lb clamp, pretty much the heaviest and the biggest in the nissan range, and actually have a small booster:) Also the vh45 is nearing the factory hp of the z32 so cant be too far out.

Will try to find underneath pics

You're not a real man till you've had a fatty:) (or so I try and convince myself)

[Mettler]

ugh... >_< fat chicks!

[kingkilburn]

Would you say that making a custom bell housing is safer/stronger than how the maworx mounts up? Would a custom bell be doable for the z32 transmission?(never seen one in person so IDK)

and +1 for fatties lol

[craigztoyz]

I had a chubby after highschool, fat girls need love too!More cushion for the pushin, really love to please their man....

I honestly think that if you get the mazworx unit, correctly machined, and mounted, it is as strong as any of the factory offerings in the Nissan group.Custom mounting is strong when built and designed right, but to get it lined up straight in all 6 axis, and to have it exactly correct is a challenge. It is possible, but from experience, if someone else has done the work, and made a durable product that you have knowledge of others using reliably w/o bitching and whining about the product, then get it. Price is not out of reasonable range. I wish it was cheaper, but, for the money the adapter, is not a bad deal. i looked alot at making my own, but with all the other customs things I am working on, that one I will farm out

[ultrapulse]

Since the z32 bellhousing doesnt separate (integral with front of box casing) you are really stuck with either making a sandwich plate or welding/butchering the front part of the z32 box (which I dont recommend, unless you can re-align spotty-dog). Also I usually find gearbox cast ali has heaps of ****e in it meaning a less than good strong weld v's new 'known' grade ali. I just know how much ali bends and moves with heat from welding, so unless the dowels are the last thing to be drilled I def wouldnt go this way. Also it ****s a very good strong box for any other use..thats if u get it right...(as I saw earlier I'm prob gunna hear about this, or as you yanks say flaming:), well handshake now?