Help with valve adjustments. Tb42.What the hell is going on

[jamied]

Ok so decided to have a go at adjusting the valve clearance on the old girl. Followed the manual step by step and made the adjustments in the correct sequence. I set them to .38 mm as per the specs. Put it all back together, got it running and went for a drive. It ran like a complete dog. Took the rocker cover back off and double checked everything and it all seemed fine. After checking everything else and finding no reason for it I started again but this time set the clearances to .48 mm. Is now running heaps better but still not perfect so I've come to the conclusion .38 mm clearance isn't right for my patrol. I have no idea why and want to know how to work out what they should be set to. Any ideas??

[threedogs]

Is it ,38 MM or .38 thou, you may also be 180 degrees out
These are specs when hot
Cold the clearance is .20mm inlet/exhaust
that will make a huge difference

[patch697]

Check this thread out mate its got all you need to know to do the job.

http://www.nissanpatrol.com.au/forums/showthread.php?603-TB42-Tappet-Adjustment


A quick question while im at it.... When you do an adjustment, how dose the feeler gauge fell??.... Is it tight, firm or just neat to get in between the valve stem & rocker?

You can throw your adjustment out by a good whack if the feel is to tight & the feel is not even throughout all adjustments.

It only needs to feel neat mate.... Just enough resistance or drag to put a little bit of pull on the gauge when removing it & thats all. & always remember to recheck your gap settings after you tighten the adjusters lock nut.

[jamied]

Its defiantly not 180 degree out. I made sure of that and it is .38 mm. I even double checked the feeler gauge using the micrometer. The feel is as far as I can tell pretty right. It's not grabbing the gauge hard but just enough so you can feel slight resistance when moving the gauge. I've double checked everything more than twice. That's why it just doesn't make sense.

[threedogs]

Do inlet /outlet at .20mm cold, if 100% look elsewhere why running like a dog?
was it rough before?? might be leaky vacuum or fuel lines.

[jamied]

No it was running fine before. Just a little bit of a Tap which is why I thought I would do them. By backing them back off to .48 mm it greatly improved how it runs who's its deffinatly to do with the adjustments. Just seems to me like the specs given arnt correct for some reason

[Bob]

Is your Truck EFI and if not take off the Tappet Cover and adjust Tappets with Motor running,
Might require two people One to adjust the clearances and the other on the Feeler Guage.
Have done this many a time on the older Motors.

[Benno7]

Is it on lpg ? I believe they should be set different if it on lpg. correct me if im wrong

[jamied]

It not LPG and its carby.

[threedogs]

Do you think someone has fitted a towing or gas cam in it??
Some people call them gas cams, but just more torque for towing

If this is the case take Bob's advice

By opening the clearance up is telling me it has larger lobes

[patch697]

Mate, have you adjusted tappets before???... Not having a shot here in any way, just trying to get a grip on the situation in order to help you get this sorted.

Given what im reading here, If the Rig was running fine before you adjusted the tappets the only thing I can come up with is that somethings been done incorrectly.

The settings your using are correct at (0.38mm / 0.015 in warm) & yet its running like crap but improves after you opened up the clearance by .010, this sounds to me like its holding valves open.

My question is how are you determining your on the right stroke of the engine when you start the adjustment process???

Like I said, not having a shot only trying to help get you sorted.

[patch697]

Do you think someone has fitted a towing or gas cam in it??
Some people call them gas cams, but just more torque for towing

If this is the case take Bob's advice

By opening the clearance up is telling me it has larger lobes

Even with a tow cam fitted .o38mm wouldn't be holding valves open as they're barely over STD. no big lift or staggered lobe centers just a slight change in duration.

[threedogs]

With the rocker cover off and running should be easy to find noisey tappet?

[jamied]

I have no idea about a towing cam. It's set up with electic trailer breaks so anything is possible. I don't have anyone here to help out so can't really do what bob suggested. I just reset them again, this time to a clearance of .406 mm. It's actually running beautifull now. Smooth idle and acceleration and a lot quieter than before. Should I leave it as is or am I able to cause damage if it's wrong?? Does it running well suggest I've got it spot on?

[threedogs]

You have them adjusted within a bees knee of OE, if it's running well put the rocker cover back on, wipe up any oil and enjoy.
You may find you adjusted them to the condition of your motor. Small pat on the back buddy.

[jamied]

Patch, no I haven't done it before and to start with I was thinking Id done something wrong but I checked and checked again everything I did. I set the timming mark on the flywheel to 0 degree and checked the rotor button was pointing to number one lead. Rockers 1,2,3,6,7 and 10 were the ones with a little play and these are the ones I adjusted, in that order. Then I turned it 180 degree and adjusted the rest. Can you see any fault here with what I've done?

[threedogs]

You may already know this but never turn the motor back if you go past your mark. turn it forwards always till you're on the right stroke again.
pain in the buttock but the only way .

[Little Mick]

The only thing i can find wrong is your not rotating the crankshaft 360 degrees.After you rotate your crankshaft valves for number 1 piston should be rocking(one opening the other closing),in other words they should be tight.Valves for number 6 piston should be loose,check your your rotor button is now pointing to number 6.Have a look at the link patch697 put up, very good info there.

[Morton]

sounds like your timing is slightly out, check to see if it is 10 degrees advanced, sometimes people advance it more then adjust the tappets accordingly, helps a little with power with bigger tyres etc