| Author |
Message |
    
Neil Cawley
| | Posted on Friday, April 19, 2002 - 07:56 am: | 
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I have secured a 4.6 liter short block and intend to put it in my 94 Discovery. I want to keep the distributor and the injection system. What mods are required to accomplish this? Also, what can/need to be done to the injection system to compensate for the additional displacement? |
Greg P. (Gparrish)
| | Posted on Friday, April 19, 2002 - 08:23 am: |
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Check out this site. Maybe these people can help with advice.
http://www.the4x4center.com/ |
Axel Haakonsen (Axel)
| | Posted on Friday, April 19, 2002 - 08:33 am: |
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Ask Craig what's involved. LR Denver put a 4.6 in Brian Jacksons Disco last year. |
Kyle
| | Posted on Friday, April 19, 2002 - 08:51 am: |
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Yeah , LRDE did put a 4.6 in Hacksons Disco last year. You need a cam , timing chain and gears , and the Timing cover off of the 3.9. You also either need a 4.6 oil pan or you need to put a small bend in it to clear the longer throws of the crank. As far as the computer is concerned I believe you just change the prom.....
Kyle |
Norm
| | Posted on Friday, April 19, 2002 - 12:53 pm: |
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I had an RPi 4.6 with a Tornado chip put in my '95 last year -- BIG improvement over the 3.9!!!
You ought to check out RPi's very informative website and e-mail Chris Crane and he can tell you exactly what you'll need to make the switch. Apparently a new fuel map chip is essential -- otherwise your 4.6 will run too lean and eventually burn up.
As memory serves, in addition to using a 3.9 camshaft (check out Piper performance cams), the 3.9 oil pickup pipe and "relieving" your 3.9 oil pan to make room for the 4.6 crank journals (the 4.6 oil pan won't fit in a Disco), you'll need a spacer, either on the crank shaft or the cam shaft (can't remember which) to allow the 3.9 timing sprockets and distributor drive to line up correctly.
You also might look into putting a mid-year '95 front cover with integral oil pump ("B" suffix 3.9 motor) as these are supposedly an improvement over the separate oil pump and front cover of the earlier 3.9s. The cam shaft thrust plate on the 4.6 will not fit with a 3.9 cam, but the "B" suffix front cover/oil pump has a peg on the inside that supposedly prevents cam knock.
Also, if you have the older 14 bolt heads, I believe you're supposed to leave the outer 4 bolts loose (or off entirely), otherwise they may cause a head gasket leak -- check w/ RPi on that. And use new headbolts!!!
Good luck!!!
---Norm |
RVR OVR (Tom)
| | Posted on Friday, April 19, 2002 - 01:43 pm: |
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Seems that this is all setup to go from 3.9 to 4.6. For us 4.0 folks does that mean buying all the 3.9 stuff to replace perfectly good 4.0 stuff?
Not contemplating, just curious...
Tom |
Craig M. Highland (Shortbus)
| | Posted on Friday, April 19, 2002 - 09:59 pm: |
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Little late here, sorry-
Kyle hit it on the head. Also either a new oilpan, or bang out the 3.9 pan to clear the new crank.
Tom- the conversion from 4.0 to 4.6 is even easier... you won't need any 3.9 components at all.
fwiw-
Craig |
Craig M. Highland (Shortbus)
| | Posted on Friday, April 19, 2002 - 10:00 pm: |
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Sorry kyle...
maybe I should read the entire thread before opening my mouth!
LOL
Craig |
Rob Davison (Pokerob)
| | Posted on Friday, April 19, 2002 - 11:11 pm: |
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craig thanks for the help yesterday.
as you can see i've made it home in about 24 hrs...
disco drives like a champ too, thanks to steve too for all his effort.
rob davison |
Craig M. Highland (Shortbus)
| | Posted on Friday, April 19, 2002 - 11:16 pm: |
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24 hrs. 
hmmmm... lot's of no-doze and MountainDew huh?
guess you had no more problems goin over 50mph...
Wish I could have done something for you on labor costs though...
Glad to hear you're home safe
next time try to plan some time in Colorado, and we'll hit the trails 
Craig |
Rob Davison (Pokerob)
| | Posted on Saturday, April 20, 2002 - 01:57 am: |
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went all natuaral and took shifts driving. i was broke when i left so i had no choice but to get home quickly.
you guys got it done in a day and thats what mattered most.
hopefully i'll be back out there next year. i fso i might look you up to do some trails!
later
rob
yes i'm still up! |
Ron
| | Posted on Saturday, April 20, 2002 - 02:56 am: |
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I think it is a ploy by LRDE.
I mean Jackson breaks and then pokerob. I see how craig gets his business. ;)
Ron |
Rob Davison (Pokerob)
| | Posted on Saturday, April 20, 2002 - 03:02 am: |
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shit he sold more stuff than what i got .. hehe
i think findlay was in there earlier in the week too, maybe he went to denver west
rd |
Axel Haakonsen (Axel)
| | Posted on Saturday, April 20, 2002 - 01:39 pm: |
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I was in there a week before Rob, and picked up a 4.0 shortblock and some other stuff on my way home. Made it home in 2 days, no problem. It was nice to finally meet you in person Craig!
Axel |
Neil Cawley
| | Posted on Monday, April 29, 2002 - 11:30 am: |
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Norm,
I looked at RPI's Web site. They have a Optimax chip. Where does the Tornado chip come from?
Thanks,
neil |
Norm
| | Posted on Monday, April 29, 2002 - 12:50 pm: |
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The Tornado chip is from RPi also, but it's for the 4.6 motor. I believe the Optimax is for the 3.9.
---Norm |
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