bitcool
13.05.2021 20:56:01
im assuming the high side is reverse seeing as the reverse gear is farthest from the shift cam (closest to the prop) hope this helps more
See full version: Shift Cam position! Please help
im assuming the high side is reverse seeing as the reverse gear is farthest from the shift cam (closest to the prop) hope this helps more
the needle bearing is at the very end of the prop shaft where it comes into contact with the shift cam. The shift shaft turns the shift cam thereby pushing the prop shaft allowing different sets of gears to come into contact with each other producing forward and reverse. Right now my outboard does not shift right so I am assuming that the shift cam is turned incorrectly and the needle bearing is hitting the wrong spot on the cam. hope that makes sense. [links]
Re: Shift Cam position. Please help
where on the shift cam is "pointed bearing?" here
Exhaust Closing: Excessively late exhaust valve closing is similar to opening the intake too soon- it leads to increased overlap, allowing either reversion back up the intake, or the intake mixture to keep right on going out the exhaust. On the other hand, late closing events can help purge spent gasses from the combustion chamber and provide more vacuum signal to the intake at high RPM. Early exhaust valve closing yields a smoother operating engine. It does not necessarily hurt the top-end, particularly if it is combined with a later intake valve opening. As engine operating range increases, designers must move all the opening and closing points out to achieve earlier openings and later closings, or design a more aggressive profile to provide increased area under the curve without seat timing increases. Exhaust Valve Closing - usually between 4 (early) and 20 (late) deg ATDC. An early closing = less overlap, late closing = large overlap. Less overlap (exhaust valve closes at 4) makes it easier to pass a smog test, smooth idle, great fuel economy. A mild overlap (exhaust valve closes at 8-12) makes good low to mid RPM range power, better throttle response, fair fuel economy, slightly more emissions. And large overlap (exhaust valve closes at 13-20) allows a lot of intake charge dilution/loss (bad emissions), poorer fuel economy, rough idle, less throttle response from idle, and makes most of the power at higher RPMs. Note: the amount of overlap also depends on the cam's intake valve opening specifications. [links]
A mild cam with an early intake valve closing point will work well at low RPM. However, at high RPM the intake valve will close before the maximum amount of air/fuel mixture has been drawn into the cylinder. As a result, performance at high RPM will suffer. If a high static compression ratio is used with a mild cam (i.e. and early intake valve closing point) then the mixture may end up being "over-compressed.” This will lead to excessive compression losses, detonation and could even lead to head gasket or piston failure. more
#1 - the most common camshaft error made by people is to OVER cam the engine.
A “tight” lobe separation angle of 103 degrees or less creates more valve overlap, which helps create that lumpy idle characteristic of big camshafts. The tighter LSA’s are, the more likely problematical exhaust reversion into the intake will occur. Put simply, we can say that a tight LSA cam produces a power curve that is, for want of a better description, more "punchy." At low RPM when off the cam, it runs rougher, and it comes on the cam with more of a "bang." Narrow LSA’s tend to increase mid-range torque and result in faster revving engines. Generally, smaller lobe separation angles cause an engine to produce more mid-range torque and high RPM power, and be more responsive. Typically, however, small lobe center numbers (more overlap) equates to more mid-range power at the expense of top-end power. Probably the most significant factor to the engine tuner though is a tight LSA’s intolerance of exhaust system back-pressure. Remember, during the overlap period both valves are open. If there’s any exhaust back-pressure or if the exhaust port velocities are too low it will encourage exhaust reversion. A cam with 102 degrees of lobe separation angle will have more overlap and a rougher idle than one with 108 degrees, but it'll usually make more mid-range power. A tighter lobe has more overlap. A tighter centerline starts torque curve sooner, and doesn't give a wide power band. A wider lobe doesn't start the torque curve sooner, but it continues to make torque longer and has a broader power band.
If you have one of the late closing cam designs installed, say one that closes the intake valves later than 40 degrees, then you cannot expect excellent performance at 2000 RPM. No carburetor adjustment, ignition adjustment or exhaust system can change this. more
What you are going to do is turn the engine until your piston is at top dead center, then remove the cylinder so as to slide it right off the piston and gently lower the piston and connection rod until it rests on the case. You can then set the cylinder aside and take a good look at the camshaft lobes. You will need a ring compressor tool on the piston to slide the cylinder back onto it. While you have the cylinder off, you should install a new cylinder base O-ring, unless you know that the one that is there is almost new.here
There is a Lyco SB that describes removing the valve covers, pulling the pushrods out, collapsing the hydraulic valve lifters and measuring the cam lift with a dial gauge. [links]
Actually, you need to remove both a front and a rear cylinder to see the entire cam. No other way to get to it.here
If you yourself are going to do this, just in case you have not done this much, I should mention that when you take the valve rockers out and want to remove the push rods, you want to be carefull not to pull the hydraulic lifters out and/or lose track of them.
Thanks Guys. That is better than a complete disassembly. I presume that a cylinder can be pulled without pulling the piston all the way out. Just enough to remove the piston pin ??
a little tiny once in a while buck is the nature of a cammed 346.. the bigger the cam , the worse it will be..
It seems as the though the timing table becomes compressed to my view in my logs compared to what the car is actually doing. VCM scanner tops out at .44g/sec while the car is using timing in the .80g/sec range in WOT. I noticed this when I swiitched to speed density(write entire). Is this some sort of hptuners bug. more
Heres my log and config so you guys can make something of this. Turns out my LTFTS are richer than i though. im on it! [links]
try playing with your throttle follower and cracker tables.
off idle, light throttle is usually in the follower table and bucking when you have your foot off the gas is usually in the cracker. here
I copied my spark tables and smoothed the whole table some. the car drives NOTICEABLY better. great progress. the car use to cruise on the highway at 1500-1600 with some bucking. now theres not bucking until <1400rpms and 0% throttle.MUCH SMOOTHER it drives great but I still feel a little bucking coming off idle in 1st gear and trying to coast at 5-10mph in 1st gear. more
any help is appreciated. Thanks