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Setting Tappets in a TB42?

Tech Talk for Nissan owners.

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Setting Tappets in a TB42?

Post by CRUSHU »

Anyone got the workshop manual for TB42 EFI, and can scan or write up the procedure for setting the tappets on it?
It is the same specs for Carby and EFI?
Is there any advantage by going tighter or looser than factory?
Can different ratio rockers be bought to increase cam size? Are there any ways to increase power while I'm there?

Also, if this attracts some good replies, could it be added to the bible?
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Post by BowTieGQ »

I should be at Paul's work Tuesday and can maybe get him to scan all you want. I don't have a scanner at home.
[quote="bazooked"]can i use a mate to position while i screw? :twisted:[/quote]
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Post by raptorthumper »

Inlet and Exhaust clearances should be 0.35mm, but if it's on gas i would increase the exh clearance as they always recess. About 0.38 to 0.4 mm, but they will tap slightly for a few kays. Every time i adjust mine the exhausts have tightened up slightly.

Here's a few photos on a TB45.




Image


Image


Image
98 GU Patrol. 4.0L Barra, BF engine. 3" Lift. 85% Marks reduction Gears. 35x12.5x15 Maxxis Bighorns, 3" Zaust.
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Re: Setting Tappets in a TB42?

Post by TEAMRPM »

CRUSHU wrote:Anyone got the workshop manual for TB42 EFI, and can scan or write up the procedure for setting the tappets on it?
It is the same specs for Carby and EFI?
Is there any advantage by going tighter or looser than factory?
Can different ratio rockers be bought to increase cam size? Are there any ways to increase power while I'm there?

Also, if this attracts some good replies, could it be added to the bible?

Hi, well i only have the carby info for ya, id say they would be similar anyways +/-..

so for a carb TB42

edit
inlet clearance is : 0.020 - 0.053 mm
exhaust clearance is : 0.040 - 0.073 mm

cheers
Last edited by TEAMRPM on Mon Apr 30, 2007 4:31 pm, edited 1 time in total.
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Post by raptorthumper »

Huh,

Those figures are wrong.!!!

20 thou is 0.508mm which is not 0.053mm.
40 thou is 1.016mm which is not 0.073mm.
98 GU Patrol. 4.0L Barra, BF engine. 3" Lift. 85% Marks reduction Gears. 35x12.5x15 Maxxis Bighorns, 3" Zaust.
http://www.outerlimits4x4.com/viewtopic.php?f=16&t=86831&start=210
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Post by waynejo1 »

TO ADJUST VALVE CLLEARANCE
(0.38 mm engine warm but not running)

1: start and run engine until it reaches normal operating temperture turn off
2: remove the rocker cover
3: turn engine in normal direction until NO 1 piston on TDC and on its compression stroke rotor button pointing to number 1 lead
4: using a 0.38 mm feeler gauge, measure the clearance betweenthe valve stem tip and the rocker arm of NO 1 inlet valve.
5: should it need ajusting ajust it
6: using same procedure check and adjust the vavles of the following NO 1 exhaust, NO 2 inlet, NO3 exhaust, NO 4 inlet, NO 5 exhaust.
7: rotate the engine one full turn to TDC rotor button pointing to number 6 lead.
8: check and adjust following vavles NO 2 exhaust, NO 3 inlet, NO 4 exhaust, NO 5 inlet and NO 6 inlet and exhaust.
9: refit rocker cover and other items removed start motor and oil leaks
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Post by TEAMRPM »

raptorthumper wrote:Huh,

Those figures are wrong.!!!

20 thou is 0.508mm which is not 0.053mm.
40 thou is 1.016mm which is not 0.073mm.
gee id hate to make a mistake mate.. ffark!

sorry BOSS!


:finger:
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Post by Mulisha »

TEAMRPM wrote:
raptorthumper wrote:Huh,

Those figures are wrong.!!!

20 thou is 0.508mm which is not 0.053mm.
40 thou is 1.016mm which is not 0.073mm.
gee id hate to make a mistake mate.. ffark!

sorry BOSS!


:finger:
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Re: Setting Tappets in a TB42?

Post by zookjedi »

CRUSHU wrote:Anyone got the workshop manual for TB42 EFI, and can scan or write up the procedure for setting the tappets on it?
It is the same specs for Carby and EFI?
Is there any advantage by going tighter or looser than factory?
Can different ratio rockers be bought to increase cam size? Are there any ways to increase power while I'm there?

Also, if this attracts some good replies, could it be added to the bible?
what do you mean by different ratio rockers? if a rocker has a fatter deeper foot etc it would make no differenc , the valves are depressed via the cam lobe height compared to the rest of the lobe , hence for more lift (down ward motion of the rocker) you get the circumfrence of the cam journal ground down but not touch the high spot if that makes cents and you keep the clearances the same , ie if you ground the closed section of the lobe down .006" your lift would push your valve down .006" more than before , but its also about valve overlap and when the lobe starts to ramp up and ramp down that matters as well depending on desired performance , in other words with out changing the profile of the lobes them selves i cannot see how you could increase lobe height , and just closing the clearances on your tappets to get more open time will cause them to burn out if they don't have sufficent time seated to disapate the heat

crude explaination i no but i hope that it helps what you were thinking about ,

cheers Jai
if its worth doing do it intensly , better still do it with MADPASSION

set your limits way beyond your abilities
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Post by BowTieGQ »

But if the rocker has a ratio of say 1.5 to 1, then one with 1.9 to 1 will effectively give the valve more lift regardless of what the cam has told it to do. Common on later model stuff.
[quote="bazooked"]can i use a mate to position while i screw? :twisted:[/quote]
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Re: Setting Tappets in a TB42?

Post by CRUSHU »

zookjedi wrote:
CRUSHU wrote:Anyone got the workshop manual for TB42 EFI, and can scan or write up the procedure for setting the tappets on it?
It is the same specs for Carby and EFI?
Is there any advantage by going tighter or looser than factory?
Can different ratio rockers be bought to increase cam size? Are there any ways to increase power while I'm there?

Also, if this attracts some good replies, could it be added to the bible?
what do you mean by different ratio rockers? if a rocker has a fatter deeper foot etc it would make no differenc , the valves are depressed via the cam lobe height compared to the rest of the lobe , hence for more lift (down ward motion of the rocker) you get the circumfrence of the cam journal ground down but not touch the high spot if that makes cents and you keep the clearances the same , ie if you ground the closed section of the lobe down .006" your lift would push your valve down .006" more than before , but its also about valve overlap and when the lobe starts to ramp up and ramp down that matters as well depending on desired performance , in other words with out changing the profile of the lobes them selves i cannot see how you could increase lobe height , and just closing the clearances on your tappets to get more open time will cause them to burn out if they don't have sufficent time seated to disapate the heat

crude explaination i no but i hope that it helps what you were thinking about ,

cheers Jai
If the tip is further away from the fulcrum, than on a stock rocker, the ratio is higher, and will creater more lift.
www.CVEPerformance.com

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Re: Setting Tappets in a TB42?

Post by marko »

TEAMRPM wrote:
CRUSHU wrote:Anyone got the workshop manual for TB42 EFI, and can scan or write up the procedure for setting the tappets on it?
It is the same specs for Carby and EFI?
Is there any advantage by going tighter or looser than factory?
Can different ratio rockers be bought to increase cam size? Are there any ways to increase power while I'm there?

Also, if this attracts some good replies, could it be added to the bible?

Hi, well i only have the carby info for ya, id say they would be similar anyways +/-..

so for a carb TB42

edit
inlet clearance is : 0.020 - 0.053 mm
exhaust clearance is : 0.040 - 0.073 mm

cheers
The way I read it he means inlet .020mm!! to .053mm!!
And ex .040mm!! To 0.073mm!!
NOT .020" equals .053mm etc
It makes sence because what petrol engine has a valve clearance of 1mm!!!!!!!!!!!!!!!!!!!!! :armsup:
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Post by raptorthumper »

He edited his post from original, and those values seem too small.

0.02mm is a tiny bees dick and not large enough.

The thickness of paper is about 0.1mm as a comparison.
98 GU Patrol. 4.0L Barra, BF engine. 3" Lift. 85% Marks reduction Gears. 35x12.5x15 Maxxis Bighorns, 3" Zaust.
http://www.outerlimits4x4.com/viewtopic.php?f=16&t=86831&start=210
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Joined: Tue Mar 18, 2003 8:10 pm
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Re: Setting Tappets in a TB42?

Post by zookjedi »

CRUSHU wrote:
zookjedi wrote:
CRUSHU wrote:Anyone got the workshop manual for TB42 EFI, and can scan or write up the procedure for setting the tappets on it?
It is the same specs for Carby and EFI?
Is there any advantage by going tighter or looser than factory?
Can different ratio rockers be bought to increase cam size? Are there any ways to increase power while I'm there?

Also, if this attracts some good replies, could it be added to the bible?
what do you mean by different ratio rockers? if a rocker has a fatter deeper foot etc it would make no differenc , the valves are depressed via the cam lobe height compared to the rest of the lobe , hence for more lift (down ward motion of the rocker) you get the circumfrence of the cam journal ground down but not touch the high spot if that makes cents and you keep the clearances the same , ie if you ground the closed section of the lobe down .006" your lift would push your valve down .006" more than before , but its also about valve overlap and when the lobe starts to ramp up and ramp down that matters as well depending on desired performance , in other words with out changing the profile of the lobes them selves i cannot see how you could increase lobe height , and just closing the clearances on your tappets to get more open time will cause them to burn out if they don't have sufficent time seated to disapate the heat

crude explaination i no but i hope that it helps what you were thinking about ,

cheers Jai
If the tip is further away from the fulcrum, than on a stock rocker, the ratio is higher, and will creater more lift.
sorry i understand what you are saying now (my bad ) i believe it is the pushrod (in apatrols case ) that is brought in that tiny bit more giving it more lift , i would also like to know if these were avalable for the 4.5ltr , just think if we ran a 350 chev we'd only need to ask who sells the rockers the cheapest :D
if its worth doing do it intensly , better still do it with MADPASSION

set your limits way beyond your abilities
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