Ford's answers to the NHTSA 6.7 Investigation
There was a request for a link to Ford's answer's to the NHTSA investigation posted on a previous thread, since closed. Here is the link: Ford's NHTSA Answers to the 6.7 investigation This PDF i...
Forum Discussion
BenK wrote:NewsW wrote:NinerBikes wrote:NewsW wrote:
Niner:
Can you do some sleuthing on the belt drive?
http://www.roymech.co.uk/Useful_Tables/Drive/Timing_belts.html
Use the table in the above link, do some measurements and you should be able to get a rough idea of how much energy / hp is being expended to drive the pump as per the chart: "Initial selection of Timing Belt ".
The pump using a timing belt is a good indication that it takes quite a bit of ommph to move fuel.
That will feed into a guess as to how much energy / heat is being dissipated into the fuel / engine area just from pumping the fuel.
14mm pitch, 30mm wide, and I know the pulley has a 3:2 drive ratio, overhead cam driven at 1/2 crank speed, HPFP at 2/3 crank speed. Redline at 5500 rpm. On my 2.0L the pulley speed is 1:1 5500rpm, same measurements on the belt. 30mm wide 14mm pitch. belt good for 130k miles. if you average 35 mph about 3700 hours life, might be higher than that to account for idle time in city traffic.
In both cases, you got all that energy dissipated into a single piston.
What is not released as mechanical energy (moving fuel) got to go as heat.
Double the load for dual piston 4.2 vs. 4.1
Use a safety factor of 100% (2X) on the chart to start....
That is a lot of energy.
Logical next step --- if one has instrumentation.
Measure fuel intake temp and how it changes as the tank gets empty on a real hot day, high rpm, high engine output.
Measure fuel exhaust temp.
HPFP temp in several different places.
Also a very bad idea using the timing belt. Thought it was the
accessory belt, not the valve timing belt
What is the belt's replacement requirement?
Before HPFP's, the timing belt was running an injector pump with a 100k mile or 7 year replacement suggestion. Since introducing the HPFP, with it's more efficient pump, replacement mileage has been upped to 130k miles, with no time limit as before. This is on VW's that run the HPFP at crank speed. the 3.0 liter using 2 cylinder heads on the HPFP is under driven with a 2:3 crank speed pulley ratio, as seen in the picture I posted the page before.
