Jump to content
SAU Community

Recommended Posts

Im about to install some tomei type b cams into my r34.

So ive done heaps of searches and it has returned multiple answers...

Does anyone know for certain the valve clearances to follow?

Ive got tomei's specs, nissan workshop specs, under my bonnet the sticker has different specs.

Just looking for some reassurance with which ones to follow, and the searching is doing my head in.

Cheers

What are the TOMEI specs for those cams out of curiosity?

I've heard they are quite large.

People have thrown shims with those cams and i'll bet its because of incorrect shim clearance.

Nissan workshop manual states it is 0.31 +/- 0.04mm on the inlet and 0.5mm +/- 0.04mm on the exhaust.

If I remember correctly (I recently installed the same cams), Tomei says the correct clearance is 0.4mm (intake and exhaust). Seemed quite large, but who was I to argue with the manufacturer :P So thats what I set mine to. I also installed stronger valve springs.

Yeah i put stronger valve springs in mine as well. But i'm only using stock cams for the time being.

Did you set your shim clearance with new shims, or did you rebuild the head and grind the valves down?

Yeah i put stronger valve springs in mine as well. But i'm only using stock cams for the time being.

Did you set your shim clearance with new shims, or did you rebuild the head and grind the valves down?

I'm not actually sure, I had the whole head rebuilt / reconditioned by someone and they set the clearances.

Yeah i put stronger valve springs in mine as well. But i'm only using stock cams for the time being.

Did you set your shim clearance with new shims, or did you rebuild the head and grind the valves down?

Valve regrind, then get your machinist to trim the valves to get the right clearance. If you get stuck and need some, Precision Shims Australia have them

From memory we set them up at 0.016" intake and 0.014" exhaust.

That's about 0.4mm intake and 0.35mm exhaust. If you set them anywhere near 0.018"-0.020" it will be noisy as hell

Mine were re-shimmed to Tomei spec 0.45mm in/ex and there is a bit of noise coming from them. Maybe noisy as hell is a matter of opinion but I would run tighter clearances in future.

Mine were re-shimmed to Tomei spec 0.45mm in/ex and there is a bit of noise coming from them. Maybe noisy as hell is a matter of opinion but I would run tighter clearances in future.

Ahh yes it was 0.45mm... Which is what I set mine too. Hope mine are not too noisy when I get it going :(

I have stage 2 Tomei poncams I'll dig up the receipts and find out what mine are can't remember lol but my head and everything was rebuilt when cams were put in. Oh I'm tuning r34 gtt neo you will love how it sounds when you got em in I know that much

Edited by Cyifly

hahaha once again I have been given several different answers.

Thank u all for the advice though.

Any more experiences?

The size tolerance you used and if it was noisy or not?

Thanks again

Do you mean noisy exhaust wise? Or as in engine cause mine is noisy exhaust wise.

Engine does make a lil bit of noise can really hear when the cams are ticking over. Hope tht answers your noise question

My poncams as per receipt:

260 degrees 9.15mm intake

260 degrees 9.15mm exhaust

Off engineering receipt:

Was machined 20 thou over by memory

List:

Modify pistons to neo spec

Repair can tunnels

Supply retainers and locks

Machine crank and fit sleeve

Supply and fit valve guides

Hot tank engine

Port head to race

Supply valve springs

Fit oversize inserts

Supply inlet and exhaust valves

Bore and hone block

Modify oiling

Supply rb25 crank shaft

Drill and tap oil gallery's

Manufacture seats

Deck block

Manufacture vernier gear

Assemble Aline pistons

Engine balance race bearings

Arp head studs

Seals

N1 oil pump

Welsh plugs

Not sure if that will help at all man but yea.

Was all done at Jhh engineering in Woodbridge Queensland.

Perhaps give em a call cause rb25 rebuilds are what they specialize in race spec.

0732086274

If anyone will have The answers they will just can't remember that far back.

Edited by Cyifly
  • 2 weeks later...

Hey all just an up date.

I checked the clearances and all good, used Nissan spec and they were all within.

The valves are making a decent tick though. Not horribly loud, just enough to be annoying.

Made just over 300 with no loss in response.

So prettyhappy

Thanks all for your responses.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • For once a good news  It needed to be adjusted by that one nut and it is ok  At least something was easy But thank you very much for help. But a small issue is now(gearbox) that when the car is stationary you can hear "clinking" from gearbox so some of the bearing is 100% not that happy... It goes away once you push clutch so it is 100% gearbox. Just if you know...what that bearing could be? It sounding like "spun bearing" but it is louder.
    • Yeah, that's fine**. But the numbers you came up with are just wrong. Try it for yourself. Put in any voltage from the possible range and see what result you get. You get nonsense. ** When I say "fine", I mean, it's still shit. The very simple linear formula (slope & intercept) is shit for a sensor with a non-linear response. This is the curve, from your data above. Look at the CURVE! It's only really linear between about 30 and 90 °C. And if you used only that range to define a curve, it would be great. But you would go more and more wrong as you went to higher temps. And that is why the slope & intercept found when you use 50 and 150 as the end points is so bad halfway between those points. The real curve is a long way below the linear curve which just zips straight between the end points, like this one. You could probably use the same slope and a lower intercept, to move that straight line down, and spread the error out. But you would 5-10°C off in a lot of places. You'd need to say what temperature range you really wanted to be most right - say, 100 to 130, and plop the line closest to teh real curve in that region, which would make it quite wrong down at the lower temperatures. Let me just say that HPTuners are not being realistic in only allowing for a simple linear curve. 
    • I feel I should re-iterate. The above picture is the only option available in the software and the blurb from HP Tuners I quoted earlier is the only way to add data to it and that's the description they offer as to how to figure it out. The only fields available is the blank box after (Input/ ) and the box right before = Output. Those are the only numbers that can be entered.
    • No, your formula is arse backwards. Mine is totally different to yours, and is the one I said was bang on at 50 and 150. I'll put your data into Excel (actually it already is, chart it and fit a linear fit to it, aiming to make it evenly wrong across the whole span. But not now. Other things to do first.
    • God damnit. The only option I actually have in the software is the one that is screenshotted. I am glad that I at least got it right... for those two points. Would it actually change anything if I chose/used 80C and 120C as the two points instead? My brain wants to imagine the formula put into HPtuners would be the same equation, otherwise none of this makes sense to me, unless: 1) The formula you put into VCM Scanner/HPTuners is always linear 2) The two points/input pairs are only arbitrary to choose (as the documentation implies) IF the actual scaling of the sensor is linear. then 3) If the scaling is not linear, the two points you choose matter a great deal, because the formula will draw a line between those two points only.
×
×
  • Create New...