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Misc questions on CJ 401/727 swap

2K views 13 replies 4 participants last post by  GP'n 
G
#1 ·
I know my rebuilt 904 currently behind the aging 258 in my CJ will not last longer behind the 401 so the 727 swap is in the works. (See www.off-road.com/jeep/tech/convtrans/conv727.html for info on how to do the swap).

I could use help on the following:

Where can I find a 401 to 727 flexplate? I know some AMC's came with them in the 1970's.

Downshift linkage - everyone mentions a downshift cable. Didn't the 727 use mechanical rods (as on Chrylser products)?

Cooling - the CJ has a 2 year old HD 3-core radiator. Will this be enough for a mostly stock 401 to stay cool? NOTE: I will be using a huge low resistance trani cooler seperate from the radiator to help the engine stay cool.

Thanks in advance for the info.
-Drew M.
 
#2 ·
i hate to tell you, but it is going to be HARD to find that.. the 401 was only made till 78 and the tf 727 wasn't used till 81... so.. there is no stock flexplate you can get.. you'll have to get one for a 360 and get it balanced by a machine shop.. you might be better in the long run to run a th 400.. maybe not.. you'll have to look at it

~~Elusive~~
it's sort of still a cj thingy....see it at http://www.jeepgod.net
 
G
#3 ·
In case my posting was unclear,I already have the 401 (BTW:$300 complete except for front p/s pump bracket and brackets for air pump and A/C - interested if you have any for sale). Yes, Santa came early this year!!!!!!:)

I posted this question a few places and check old postings. Here's what I learned/found so far:
FLEXPLATE: the AMC 401 was used with the Chrysler 727 in the early 1970's cars so just order the flexplate from one of these applications. i.e 1972 Ambassador 401 with an auto - it's a TF and not a Turbo 400.

Still looking for info on other questions. Thanks.
-Drew M.

 
#4 ·
your radiator should be enough.. my 401 came out of a wagoneer that had a 3 core in it.. about the size of a cj one.. Elusive is running that radiator in front of his 304..
not sure about your downshift linkage.. im sure ozarkjeep will be able to help you.. he is the local 727 guru..
ummm.. your flex plate? if you know what it came in .. cant the auto store order one for you? try napa or someone.. instead of crapozone.. there is a place in florida that deals with alot of amc car stuff.. i might be able to find their website for you.. and another place in wisconsin also.. ill look tonight..

survival is instinct, but living takes guts
 
#5 ·
the flexplate is availble at Oreillys for about $45, ask for an early 70s amc v=car with a 401.

the amc 727s used a mechanical Kickdown linkage just like chryco, but its hard as heck to find one, look for a 80 or newer Grand Wagoneer in a salvage yard and get it there..

thats why alot of folks suggest the lokar cable type kickdown, But Ive never used, or seen one

OzarkJeep
77 CJ5, in a bunch of sanded and primered pieces
 
#7 ·
shim behind the starter on a AMC V8 Tf727?

not that I have ever seen
Ive only messed the older ones ( before the late 80s) which used the FORD starters with a differnt nose cone and gear, the later AMC V8s TF727 used a motorala starter, it might possibly have a shim!


OzarkJeep
77 CJ5, in a bunch of sanded and primered pieces
 
#9 ·
I have NEVER seen a delco ( GM) starter on an AMC engine.

only Motorcraft, and Motorola ( I think motorola for the newer ones)

does the starter have the solenoid built onto it?

what do you mean by "hard"?
grinding?


OzarkJeep
77 CJ5, in a bunch of sanded and primered pieces
 
#10 ·
sorry..not delco...motorcraft
it starts slow and makes that bad noise startes make when they need a shim.. i put a new starter in it, but it still starts slow.. i have plenty of juice in the optima...it doesn't grind, but on occasion the teeth wont mesh and they hit the teeth on the flexplate

~~Elusive~~
it's sort of still a cj thingy....see it at http://www.jeepgod.net
 
#11 ·
it sounds more like a amperage draw problem, or maybe some internal resistance, was this hte same engine awhile back you couldnt get to rotate?

Ive never messed with any starter that needed shims
but out of the several AMC V8s Ive put motorcraft starters on/off of none had shims

sorry I cant be of any help on that one

usually the grinding or freewheeling is a dead spot on the ring gear
or a bad bendix thingy in teh starter
was it all good when you had it apart?
OzarkJeep
77 CJ5, in a bunch of sanded and primered pieces
 
G
#12 ·
Starting around '87, Jeeps started using Mitsubishi gear reduction starters. They have a solenoid mounted in the same manner as a "Delco" type starter. If you have one of these, you need to use the '87 or newer flexplate as the starter ring gear is located differently. The new ring gear position is around a 1/2" closer to the starter, this could be your grinding problem, shims will make the starter drive move farter from the drive gear! There is no factory flexplate that will work with the 401 and the new style starter. You could balance a 360 or 6 cylinder plate to match if you were having the engine balanced during assembly. Most of the kickdown parts are still available at the dealer, ask for a '91 Grand Wagoneer, but the Lokar cable may be cheaper if you can't find them at the wrecker.
Hope this helps, good luck!

 
#13 ·
i saw the gear reduction starter when i was starter shopping... it wouldn't fit..at all! yes ozark.. same engine.. but i pulled the tranny bach out and put the plate between the engine and tranny(about 1/8" thick") and it seemed to cure a lot of problems. this is a balanced 304, so i used a neutral balance flexplate for an 80 jeep(tf 904) luckily it had both the small and large bolt holes in it and it bolted in.. the starter is new, the flywheel in new, i tried a different starter, and i have lots of juice going there.. I'll keep looking.. i think something is still binding a bit, but i have about 200 hours on it driving around now... thanks guys.hmmm.. my tf 727 came from a 88 grand waggoneer.... think it's different?

~~Elusive~~
it's sort of still a cj thingy....see it at http://www.jeepgod.net
 
#14 ·
Could be a bad nose cone on the starter, Motorcraft starters never used a shim of any kind on the starter to motor mount up on any of the 304-401 family motors. May be a weak bendix on the starter not throwing to full reach. Check wire connections on the solenoid for loose mounting this will cause slow to no starting, or wind up.
GP'n
 
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