late model explore V8 conversion
I spent some time looking over the late model explorer engines. I would like your thought / comments. Here is what I found:
I inspected three engines. Two from 96 year, one a late 97 year (9/97).
1) All the engines had the standard GT40 heads. They did NOT have the P heads. I verified this by checking the stamping on the casting. The GT40 heads have "GT"stamped on the heads and 3 vertical bars in the end of the head casting. The GT40P have "GTP" stamped on the heads and 4 vertical bars in the end of the head casting. I was surprised that the late 97 model still had the GT40 heads.
I have called the conversion companies and got the following responses:
Total Performance: Does not know if their conversion headers will work with the GT40P heads.
Kaufmann: Their headers do NOT work with the GT40P heads.
James Duff: They are not sure and have not tested it themselves. They claim customers have bought the headers to use on the GT40P heads, but have never received any feedback.
L&L Products: They believe their headers will work with the GT40P head, but have not tested this configuration themselves.
2) The EGR on the GT40 heads were internal, and that is how the engines I looked at were set up. Ford manuals and other things I have read say the Explorer EGR is an external system, but this must only be for the later model P heads.
This is confusing because all the pictures (I stress they were pictures) of the Explorer intake manifolds I've seen were missing the EGR hole from the upper plenum. Leading me to expect an external EGR system.
Are the early manifolds different from the late 97- 99 manifolds?
What does it mean????
a) The early explorer V8 with GT40 heads will fit better with conversion headers (spark plug clearnce).
b) The EGR system is internal, so no additonal plumbing needs to be added to the exhaust manifold (header)
c) Performance of the GT40 is NOT as good as the GT40P, some mildporting could help that out.
3) There is NO air pump on the Explorer, good news. BUT, the 93 EEC IV computer expects one. It will be necessaary to "fake it out" by wiring in the Thermactor Air Bypass (TAB) and Diverter (TAD) into the wire harness, but not into the engine itself. This should keep the check engine light from coming on. There might also be a way to jump the connector pins and avoid using the solenoids altogether.
4) Throttle position sensor on the explorer uses a different connector than the 93 wire harness, but both are three wire systems. It should just be a matter of replacing the harness connector from the explorer into the 93 engine wire harness. (The explorer uses a 4 pin round connector with three wires attached).
5) The explorer needs a 93 distributor ignition system. This should be straight forward. You won'tuse the EDIS module and coil packs. Instead use the 93 mustang distributor and coil. I would recomend checking or replacing the distributor gear with the proper "hardened steel" gear that is compatable with the hardened steel roller cam.
When installing the distributor set the engine to TDC and line up the rotar with the #1 spark plug wire position of the cap.
6) Air Charge Temp (ACT) sensor will need to be moved. On the explorer V8 the ACT is located in the air tube between the MAF and the TB. The Explorer EEC V performance curve is set up for this temperature reading. The 93 EEC IV computer expects a "warmer" reading as the sensor is located in the lower intake manifold.
To prevent performance issues the sensor needs to be located in the lower intake manifold on runer #5 (front runner on the driver side). There is a "land" there in the casting. It needs to be drilled and tapped (I don't know what size yet) If you have the right drill and tap this is easy. This should be dead easy for a machine shop to do. Clean it very good, then clean it again before installing.
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Overall it shouldn't be too bad todo the conversion.
I do start to wonder about meeting emmisions standards however. The explorer engine didn't require the air pump, but the EEC IV computer did. Which applies? My gut feeling is that it should pass the sniffer test, but might fail a detailed visual inspection (But who does a real detailed visual inspection).
Any thoughts or comments???
