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We jetted down primaries and secondaries. Haha yes when i decided to run a 502 gas mileage was not on the radar.
It´s ok to me wasting fuel when it's fun, but it doesn't have to be more than is necessary for fun. On the first test drive with the 780 cfm we had a consumption of 4 mpg, after jetting down it was significantly less, but the behavior of the carburetor did not satisfy me.
17.5 mpg for a 400 hp engine is really very economical.
And yes, I admit that I'm now wondering whether the idea of the 850 double bumper was such a good one.
In the meantime, we also jetted down the 850 cfm carburetor because we had an AFR of 10 at idle.
We also replaced the powervalve, with a vaccum of around 12, a PV of 4.5 was installed, which was probably already open at idle, now we installed 5.5 PV.
Currently i hav no chance to testdrive because its raining almost every day.
If you are experienced with carburetor tuning I will gladly accept your tips.
The PV number is the vacuum at which the PV opens. If I read that right you went from 4.5 to a 5.5 which means the second PV opens sooner, e.g. 5.5 inHg instead of 4.5inHg. Vacuum in a NA engine drops with throttle valve opening. If that is what you did it will be richer earlier. To rich also hurts performance.
The PV number is the vacuum at which the PV opens. If I read that right you went from 4.5 to a 5.5 which means the second PV opens sooner, e.g. 5.5 inHg instead of 4.5inHg. Vacuum in a NA engine drops with throttle valve opening. If that is what you did it will be richer earlier. To rich also hurts performance.
@truckeemtnfords he told me that 5.5 is the Powervalve which matches better the Vacuum, but what you are telling makes sense to me, so i better try a 3.5 PV to make sure it does not open too early !?
As the engine reved too high for me at cruising speed, I changed the gear ratio from 3.70 to 2.75. Since i am still in the process of converting the brakes to hydroboost, so I have not yet been able to test ride the Truck with the new gear ratio.
What transmission are you running Ingo ?
I also am running a 2.75 rear end and find it great for highway cruising , but it's also still ok for normal driving .
But it will not be so good if you have an overdrive trans .
What transmission are you running Ingo ?
I also am running a 2.75 rear end and find it great for highway cruising , but it's also still ok for normal driving .
But it will not be so good if you have an overdrive trans .
Scott I´m running a 3-speed automatic transmission C6. As I have plenty of torque with 502 ci, I'm not worried about this.
An overdrive gearbox would certainly be a good option, but it would certainly be an expensive conversion.
As I wasn't happy with how my brake pedal felt when braking, I decided to upgrade to a Hydroboost brake booster....
I removed the good old piece from a friend's Chevy G20 Van.
As this neck was too long, I first had to fabricate an adapter.
after that i noticed the original Chevy retaining plate was angled and i couldn´t use it neither in one direction nor in the other, i had to make my own.
In the meantime, I have driven the truck almost 800 miles and assume that the new engine has been broken in.
On Friday morning I drove off in the truck and after a few minutes I noticed an unusual engine noise. I immediately aborted the journey and drove to my garage. At first I feared a main bearing or rod bearing damage, but after listening more closely I assumed that it could be a defective hydraulic lifter. So I removed the valve covers to check this. It seemed to confirm that at least one hydraulic lifter was broken. So I dismantled the intake manifold to be able to remove the tappet.
I then dismantled the tappet and lo and behold... A valve plate was broken inside the tappet.
We still had a good smoked hydraulic tappet left so i just had to order a gasket set for the intake manifold. So I hope to have the engine running again tomorrow.
debris i found between rocker and pushrod
i checked one more lifter but it was okay inside:
Yesterday, I was on the way to a car Show with my Truck when, after accelerating a little harderl, I heard that unusual clacking sound again, just like about a year ago... and lo and behold, another hydraulic lifter has broken. Obviously, low-quality lifters were used here. So now I'm going to order a complete set of new hydraulic lifters.
Guys, what is your experience with hydraulic lifters? Which brand would you recommend?
I think his point here is that a failed lifter like you experienced is a rare occurrence. You could choose from any number of name brand parts and should be fine. It's entirely possible you got a cheap offshore copy in a house brand cam kit. Unless you know what brand yours was, you don't know what to avoid.
That's good for you, ebear, but unfortunately it doesn't help me here.
Sorry I should have worded it differently but you did ask for our experience also . I do run a repair shop and have rebuilt or repaired a number of engines over the years and have never had or heard of a lifter coming apart as yours have . Very curious also that your two lifters were some time apart . Happening immediately would make one think of simple poor manufacturing but yours is odd . Not enough oil flow ?
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Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.
