I was wondering if anyone has measured the actual valve lash on the Tocama 4.0 engines to compare to specs. The stock valve lash specs have a wide range if you look at the sticker under the hood. I am sure this could account for why some get better gas mileage than others. The tighter the lash the more top end and duration and lift on the cams was well as quieter operation.
Solid lifter cams in the 4.0 engines
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I haven't measured them yet but I wouldn't be too surprised if a lot of "Ticking" problems stemmed from a loose valve or two on some of our trucks. Mine doesn't tick but I will check the valves if all of a sudden it starts as the miles pile on.
By the by, they are not solid lifters. They are shim under bucket I believe. You have to remove the cams to change a spacer for adjustment.
By the by, they are not solid lifters. They are shim under bucket I believe. You have to remove the cams to change a spacer for adjustment.
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They are shim bucket hydralic lifters. I had the dealer adjust mine to the tightest tolerances and nothing happened. I still get about 16MPG and my engine still ticks.:dunno:
They had a team of their "Master Techs" working on it for about 3 weeks, at their research center.:disappoin
They had a team of their "Master Techs" working on it for about 3 weeks, at their research center.:disappoin
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is the ticking while at idol not normal?
There are two different "ticks". One is associated with the exhaust manifold TSB.Subaruguy86 said:
The second, is a tick that sounds like its valve train related. Mostly noticable on mine at lower RPM's. Lotust has the worst sounding one, his sounds like a diesel. This is the one we are refering to. They say its normal, I say its not.
I was hoping someone would have had this done and fixed the problem! Damn.toku58 said:
For the 1grfe (v6), the total clearance range (tolerance) on the intake and exhaust, each, is .004" (4 thousandths of an inch). Not really what I would call a wide range. They are solid lifters, not hydraulic.
Spec is (cold) Intake: .006 to .010; Exhaust: .011 to .015.
There is no "SHIM"; as in a little sliver of metal that is specific thickness (ex .001) that you insert between the lifter and cam or something else. The whole lifter is sized to a specific thickness. You have to replace the whole solid lifter with one of the correct thickness to change the clearance.
It is all in the Svc manual: R.M. 2006::1GR-FE Engine Mechanical: Valve Clearance: Adjustment (Tacoma)
Here is an excerpt :
HINT:
Lifters are available in 35 sizes in increments of
0.020 mm (0.0008 in.), from 5.060 mm (0.1992
in.) to 5.740 mm (0.2260 in.).
Changing the lifters is no easy task. The Cams have to be removed along with the timing change tensioners. I don't think Toyota expected them to be changed/adjusted much, if at all (even though our svc manual states that the clearances need to be checked every 30/60k miles or so).
The 4 cyl engine (2trfe) has self adjusting hydraulic lifters. You don't ever have to mess with them.
Spec is (cold) Intake: .006 to .010; Exhaust: .011 to .015.
There is no "SHIM"; as in a little sliver of metal that is specific thickness (ex .001) that you insert between the lifter and cam or something else. The whole lifter is sized to a specific thickness. You have to replace the whole solid lifter with one of the correct thickness to change the clearance.
It is all in the Svc manual: R.M. 2006::1GR-FE Engine Mechanical: Valve Clearance: Adjustment (Tacoma)
Here is an excerpt :
(3) Select a new lifter with a thickness as close as
possible to the calculated value.HINT:
Lifters are available in 35 sizes in increments of
0.020 mm (0.0008 in.), from 5.060 mm (0.1992
in.) to 5.740 mm (0.2260 in.).
Changing the lifters is no easy task. The Cams have to be removed along with the timing change tensioners. I don't think Toyota expected them to be changed/adjusted much, if at all (even though our svc manual states that the clearances need to be checked every 30/60k miles or so).
The 4 cyl engine (2trfe) has self adjusting hydraulic lifters. You don't ever have to mess with them.
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The ticking at idle is the fuel injectors. Different than the exhaust related tick.
wjdunn3 said:
I am rebuilding a my Nissan 300Z doing a solid lifter cam conversion from hydraulic. Depending on where the ramp starts on the cam it self. .001 makes a big difference if you are on the end of the ramp profile vs. the beginning of the ramp profile. The begininng of the ramp profile makes very little difference on the tight side. It all depends on how aggressive the lift is on the cam profile ramps.
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Also the tighter the lash the more likely the valves are to burn. Actually valves are more likely to tighten up with age as they wear into their seats. This is a common misconception.zmanphx said:
Also, how does higher duration equate to better gas mileage? It's driving habits that determine your gas mileage the most.
Now you guys have me worried:ugh3: . I've checked my truck at startup at -10, at idle, at 2000rpm, at full operating temp, after extended periods under load, I've parked next to retaining walls, I've tried everything I can think of and my engine won't make even the slightest tick! Nothing from the exhaust area, nothing from the injectors, nothing from the cam areas. What's wrong with my motor?? BTW, you guys might be onto something about the lash changing ultimate valve timing(after the VVT-I does it's thing), This truck has way more power than it should, even compared to other Tacos I have driven. O well, I guess I'll just have to live with it....
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My old Subaru STi ticked. My Tacoma ticks, I figured it was normal and from what people say it is. It runs fine so I could care less about how it sounds as long it dosnt sound like one of Hillarys speaches!:disappoin :lol:
My X Runners injectors tick. My Old GTI's tick, my Old Corvette's ticked. I've heard BMWs, Audis. mercedes all tick. You should hear the new VW/Audi 2.0 Turbo FSi tick, real loud.01rk said:
There electrical solinoids. They tick, its just what they do.
My nephew has new pilot, when he comes over and both vehicles are running side by side, I can not hear his engine at all but I can hear mine ticking. I do not know if it has anything to do with gas octane, I've tried 87-93 gas and have not notice any differance at all.
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