At 08:30 AM 3/4/2000 -0800, you wrote:
>Hello:
>
>I've successfully extracted the non-stock engine from my MK1. I'm
>seeking ideas about what to do different when I rebuild. My main
>complaints about the previous engine are: (1) summer over heating in
>stop and go traffic, (2) poor fuel economy (ca. 12 mpg), (3) rough idle.
>
>I've determined that I have a 302 cast in early 1969. The heads are 2V
>and the cam is a ford hi-performance hydraulic cam from the same era.
>The distributor is a ford dual point, mechanical advance only, from late
>1968. I have an Edelbrock Torker 289 manifold--I'm told by Edelbrock
>this is most similar to today's Torker II 302. The carburetor is a
>Holley 1850 600 CFM. I had the radiator rebuilt last year, and that
>seemed to help the over heating problem some, but did not completely
>eliminate that problem.
>
>I intend to drive the car on the street and have no plans for racing or
>showing the car. Some moderate amount of performance intersts me
>(because it's fun!), but I would like the car to be reliable and trouble
>free.
>
>I'm thinking that I should change the manifold to a Performer or
>Performer RPM and maybe the cam and/or carburetor, but I would like to
>hear what you all suggest. Thanks in advance for your feedback.
>
>Mark Burnett
>B9471102
Mark,
Poor fuel economy possible causes:
1. Uncalibrated odometer.
2. Bad Carb,
Jets too big.
External leak
Internal leak due to bad body gaskets.
Wrong power valve, operates at too low a vacuum
Power valve leaking.
Fuel pump pressure too high.
Float level too high.
Idle circuits clogged.
Holes in body that the throttle shaft passes through worn
and the plastic "seals" around the shaft are bad.
Leaking intake manifold.
3. Fouled plugs.
Dirty air cleaner
Wrong plugs (too cold)
Weak ignition
If there is a braided ground wire from the dist.
plate to the
case then it needs to be good as it is the ground
return
for the points.
Bad points
Bad condensor (should match coil)
Dwell wrong
Bad low voltage wires/contacts.
Bad Rotor
Bad Dist. cap.
Bad coil
Wrong coil (ignition) resistor
Bad plug wires
Bad plugs, worn, broken or gapped wrong.
Timing wrong,
Set wrong
Vacuum advance dist usually giver better milage.
Electronic dist, even the early 70-80 model Ford
magnetic pickup
dist and matching module works better than points.
Oil fouled
Worn valve guides
Broken valve stem seals.
Worn rings.
PCV valve.
Clogged up
PCV hose leaking.
Carboned up area under carb used to suck fumes from
PCV hose.
Fuel fouled due to too rich carb, (see carb above)
4. Low compression with hot cam just wastes gas. Need at least 10.5
compression
with your hot cam. The higher the better until limited by available fuel
octane. Low
compression needs a mild cam for economy. The 69 302 2 barrel came with
9.5:1 compression
but the 73 came with only 8:1. Your 302 may have been rebuilt at least once.
No telling what the compression is now. The 289 Hi-Po came with 10.5: 1
compression,
sounds like you have the 289 Hi-Po cam or equivilent.
5. Valve springs
Extra strong valve springs for high RPM use cause a waste of
gas compared
to stock springs if you do not drive above 5000 RPM a lot.
Takes more
power to compress the strong springs.
Broken Valve springs
Valve springs too weak, not closing valve properly.
6. Valves/Heads
Excess carbon build up on back side of valve.
Valve not seating due to wear or burned valve/seat.
Unleaded gas will cause the exhaust valve seats to be beaten
out on a 69.
Need heads rebuilt with hardened valve seats for unleaded.
Leaking head gasket ( usually between cylinders).
Lack of oil to rocker arms ( galled rockers take more power
to operate)
Top of valve stem and or tip of rocker worn.
7. Cam
Too hot a grind for compression, see above)
Worn lobes on cam
Worn Lifters
Timing chain worn and therefore cam timing off.
8. Rings
Worn out rings and scored cylinder walls, gives low compression
and oils plugs.
Brand new rebuild with end gap too close will consume a
lot of power and possibly waste your new bored cylinders.
9. Rear end
Small dia tires or stiffer gear ratio will lower your milage.
Too large diameter tires may also lower your milage if the
driving is mostly in town and you are lugging the motor.
10.Low air pressure in tires waste fuel.
Recommend at least 30 psi.
Radials normally give better milage than the old bias tires.
Radials with weak sidewalls waste more gas than stiffer
sidewall radials. Cheap off brand tires often have weak
sidewalls.
Wide tires waste more gas than narrow tires.
11. Automatic transmission can drop 2-3 mpg compared to manual.
12. Heavy foot and a lot of tickets weighing down the Tiger.
13. Carrying a lot of extra weight in Tiger. 100 lb extra weight
equivilent to
about 10 Hp loss in 1/4 mile drag race.
The above are just a few of the things that may be causing your problem.
Items 1 to 8 may cause rough idle well.
I used an 1850 600 CFM, Marine cam, F4B intake, 351 Winsor heads,
and pop up pistons for 10.5 compression ( carefully calculated/ measured) on my
original Tiger 289 motor. Typical milage was 18-19 in town and 22 on the road.
Power much better than the stock 2 barrel Tiger 289. Valve float at 5400 due to
stock (351W) valve springs.
I have had almost every one of the above faults over the 33 years of
my Tiger II. The only exclusion is the weight of traffic tickets. Never had
ticket in the Tiger. Did get a warning for 40 mph in 30 zone once. When I
pulled over into a dirt parking lot and stopped in a big puddle of muddy water.
It took me a long time to find my latest paperwork as I had registerations for
10 years in my center console. Meanwhile the cop was standing in the puddle
with rain comming down. I think I got the last laugh.
James Barrett Tiger II 351C and others
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