what should i expect from this engine ? (revised)

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diymirage

diymirage

HP@idle > hondaHP@redline
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so, i bought this engine and tranny to put in my 71 duster (/6-904)

ill post a few pics, and then get my thoughts straight (ill try not to ramble)











so, it is a 75 360 out of a motor home
(apart from a good cleaning) the tranny should be all set

i should hook up a tranny cooler (not sure if my 904 has one, and if it does, could i use its lines?)

the thing i thought was a sensor is the neutral switch/back up light doohichky, again, use it or does the one from the 904 work?


on to the motor, i think the best way to determine the state of the engine is to get it on a stand and check the compression on each cylinder, if they are all good i will leave the heads on and the pistons in place

the oil pan is a truck unit with a rear sump so it and the pickup need to be replaced

i should check/replace the timing chain/gear and water pump

valve springs, can i assume the springs are good if the compression it?
i almost feel like if i go through the effort of replacing the springs i might as well put a new cam in there while im at it.

the carb will also need a good cleaning, maybe just replace it while im at it?
same goes for the intake

ignition, someone suggested the distributor might be geared more towards hauling stuff and should be recurved


oh, accessories, the /6 has powersteering, AC and a alternator
i would prefer to use the /6 parts since they are hooked up, will they bolt up to the 360 mounts?
the accesories on the 360 looks quite different and seem to be oriented different aswell

(maybe the alternator on the 360 is a higher output unit and would be worth considering?)


any other thoughts?
 
diymirage said:
i should hook up a tranny cooler (not sure if my 904 has one, and if it does, could i use its lines?)

the thing i thought was a sensor is the neutral switch/back up light doohichky, again, use it or does the one from the 904 work?
Click to expand...

904 cooler stuff should hook up, you may or may not need to transfer the adapter fittings right at the transmissions. The two neutral / backup switches should be the same, use this one bein's it's there



diymirage said:
on to the motor, i think the best way to determine the state of the engine is to get it on a stand and check the compression on each cylinder, if they are all good i will leave the heads on and the pistons in place

the oil pan is a truck unit with a rear sump so it and the pickup need to be replaced

i should check/replace the timing chain/gear and water pump

valve springs, can i assume the springs are good if the compression it?
i almost feel like if i go through the effort of replacing the springs i might as well put a new cam in there while im at it.

the carb will also need a good cleaning, maybe just replace it while im at it?
same goes for the intake
Click to expand...

You could even fire it. Here's what I do.......just hang it from chains. You can rig up an ignition pretty easy, using either Mopar ECU or an HEI module. Here's the diagram, what it looks like. I just hang the engine from chains and fire it up

Definately check compression, and you'll need a 360 pan. I would change the cam drive, but not necessarily the cam until you "know what you have." I would not mess with the springs.

I also would not mess with the carb for now, unless it's simply so bad it won't run

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hwlcfa.jpg


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diymirage said:
ignition, someone suggested the distributor might be geared more towards hauling stuff and should be recurved
Click to expand...

Probably so, but I'd get it running and driving first with the one that's in there. Since this is a "truck" the advance curve might be better than the smog cars as it sits. Make sure it has a vacuum advance, AKA "is not" a lean burn setup


diymirage said:
oh, accessories, the /6 has powersteering, AC and a alternator
i would prefer to use the /6 parts since they are hooked up, will they bolt up to the 360 mounts?
the accesories on the 360 looks quite different and seem to be oriented different aswell

(maybe the alternator on the 360 is a higher output unit and would be worth considering?)
Click to expand...

You might be able to remove your slant pump from it's engine bracket and transfer to the V8 bracket, and may not. You WILL need the V8 bracket, so you may have to use the V8 pump

Alternator will interchange unless one of them is the large frame, and one the small frame. Difference is obvious. If they look similar, they will interchange. Whether the new one is better / working condition or larger capacity is a tossup. This is easy to change later

Most all accessories, like ps pump AC etc will not interchange without changing to V8 brackets


Also, you'll have to do something else for exhaust manifolds or headers, those won't work. You have a V8 K member to swap in, else you'll have to buy "swap" motor mounts, like this:

http://www.engine-swaps.com/

The 904 and 727 are different length so you'll need to shorten the drive shaft and get a different front yoke. Trans mount bolts up.
 
thanks, thats a lot of good info
i plan on using the conversion mounts and buying a full exhaust
still need to price out if i can have a shop do it or if i should get the jeggs kit and piece it together myself

for the rear end i want to get a 8 1/4 or bigger at the same time so i only need to mess with the driveshaft once

(im a little intimidated by this swap so expect plenty more questions)
 
Don't be intimidated, it just nuts and bolts. Been done plenty of times and tons of info here. Buy good headers the first time, TTI or Dougs. Consider your cooling as well. May need a larger V8 radiator. You'll need to rewire the car for electronic ignition if not all ready done.
 
Del covered a lot but here's a few things to add

Just because the engine has compression doesn't mean the valve springs are "good". It doesn't take a lot of pressure to close the valves to get good compression readings but it does take a fair amount to keep them seated when the engine is running, especially at higher rpm. I found this out back when I was a kid and bought a Chevy with a 350 in it that idled great but at about 1500 rpm started missing. Pulled the v covers and found I could push 3 valves down by hand pretty easy. Replaced the springs and problem solved.

You mentioned that if you have to replace valve springs you might as well replace the cam. If your up for quite a bit more work (cam's are not plug and play, you have to go through a break-in process) that's fine but if you just want to get it running why go to the extra work?

The alternator should work fine with your car. Should be plug and play as it uses the same wires but since your car has a /6 wiring harness I'm not sure about the wires reaching properly. Worse case you may have to lengthen (or shorten) some wires.

Since it is such low mileage why replace the carb unless your looking to install a 4 barrel to improve performance. If your ok with a 2 barrel just do a rebuild on the carb. Those 2 barrels are extremely simple.
 
i had forgotten about the break in period of the cams :(

i would prefer to keep it as simple as possible but i do realize that might mean doing more work before i install the engine to save me from having to pull the engine to do the work

i keep going back and forth between dropping her in the way she is to get a good baseline idea of what ive got and just doing a full build up refurbish on her to KNOW what i go

then again, it seems like quite a bit of work already


as for the carb, i was told by the PO that it would need a decent cleaning
(little background info)

the engine came out of a motor home the lady had gotten in a divorce, not that she wanted it, she just didnt want him to have it
it sat for several years and at some point the roof started leaking
she didnt care much so she let the entire interior go to mush, the floor buckled and she called the guy i bought it from to haul it away

he scrapped the motorhome and left the engine in the frame while he put it for sale in craigslist so people could here it run
then last week he decided to scrap the frame before winter hit, so he pulled the engine, dropped the price and i bought it without hearing it run
all that to say, he said it did run, idle well on its own but bogs a little under throttle before revving up, like a secondary is hanging up

so the carb does need cleaning

is there any way to check spring pressure?

if i pull the valve covers and push on them should i find no movement and i i find any they are bad?
 
Without a doubt going through it completely is the best way to go. Do it once, do it right is my motto. Of course you have to have the money and time to put into it. With winter coming on you most likely won't be driving the car much anyway and if you have a garage I say go for it. If you have the money for a roller cam their a lot less hassle than a flat tappet cam (no break in period or using special oil) and make more usable power than a flat tappet hydraulic

I don't think anyone makes a tester to check springs on Mopar heads. Pushing down on them by hand can give you a ball park estimate if their good. They should be really hard to push down by hand. Nothing short of a pressure tester will really tell you how good they are and that requires removing them for the test.

Hot rodding is a lot of work but doing everything once with the engine out is a lot easier than doing it after it's installed, imo
 
My opinion, if its life was in a heavy motor home then its been used well. Even if maintained well. If it were me I'd rebuild it, knowing I'm installing something fresh and will perform to my expectations. Also remember, the chassis too need to be able to handle whatever you build.
 
as much as i agree with the full rebuild being the best option i want to not spend that much money on it ...at once

i figured between the rear end, drive shaft, radiator, headers, exhaust and everything im overlooking im probably another $1200.00 shy of finishing the conversion

so i want to get the engine cleaned up and going this winter, enjoy it for a summer and then next winter rebuild/upgrade the engine

as far as chassis upgrades go, what should i be looking at?
bigger torsion bars? heavier struts? larger brakes?
all that stuff is something i want to address but the budget only stretches so far so if figured i would get the big ticket item done first (the conversion) and then upgrade parts as money becomes available
 
If the car runs and drives now, why not just enjoy it the way it is, until you get the engine rebuilt and everything else in order.
 
I will share with you what I did . I put this car together only to drive it . my daily driver , every day of the week, my only transportation, so it had to be reliable. I started this Saturday morning and had to have it running to get to work by Monday morning.
73 duster
slant 6 / 3 speed , 7 1/4 rear , 10 inch front drum , 9 inch rear drum

I bought a 318 / 727 off CL for 400 sight unseen and I knew nothing about it. the guy said it ran
conversion mounts
long tube headers
727 yoke
40 dollar radiator and shroud out of an 88 lebaron from pull n pay
engine dress up stuff, 4 barrel intake and 1406 carb
I literally have less than 1,000 bucks in the entire thing.
I used all my original wiring and trans mount. I had to shorten my drive shaft 4 inches because the 904 / 3 speed transmissions are 31" and the 727 is 35". the V8 doesn't weigh much more than the slant.
I had the slant out and the 318 running in 10 hours in the dirt and I even cleaned the engine bay and painted the engine.
I drove this car for over 2 years on the original suspension. it never let me down ever, and I even beat on it a few times. it is still on the road to this day the same exact way I set it up. don't over think it. it a simple swap. you can easily upgrade the suspension and other components down the road while enjoying the car. theres more than one way to skin a cat.
 

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Bad Sport said:
If the car runs and drives now, why not just enjoy it the way it is, until you get the engine rebuilt and everything else in order.
Click to expand...

it does run and drive, but it is slow
when the wifeys truck was in the shop last week we got a loaner car, a dinky toy of a toyota and it was spunkier then the duster...thats just not right
besides, 2 more weeks and there will be snow everywhere and ill be back to driving the winterbeater so that would give me a few months to get the /6 out and the 360 in

but if you want an honest answer, the reason i want to swap in the V8 is because i want it i want it i want it


73AbodEE
that sounds like a good way to go about it
i do want to change out the rear end while im at it so i dont need to mess with the driveshaft more then once
not sure what it would cost to have one shortened and balanced but there is a company local to me that will build me a custom driveshaft for about $250
 
I had my driveshaft cut and balanced for 55 bucks at a local driveshaft service center.

the slant was a complete dog. I am a V8 guy, so it was a no brainer for me. the slant got tossed in a ditch lol
not to mention I had kick *** heat for the winter
 
diymirage said:
but if you want an honest answer, the reason i want to swap in the V8 is because i want it i want it i want it

LMAO, I know, but IF you take the time to rebuild it, paint it, clean the engine compartment etc, etc etc, when you do make the swap you won't have any more "doings" going on in there. Plus it would give you time to save a bit for the other accessories you are gonna want, and you know you will :D , cam, headers, intake and carb.

Just a thought.



not sure what it would cost to have one shortened and balanced but there is a company local to me that will build me a custom driveshaft for about $250
Click to expand...

There is a place down by me that shortened mine for 90 bucks, installed the U joints I provided, balanced and painted. I don't know if you get down by Jackson much, if at all, but they build drive shafts and do excellent work.
 
yeah, i never get close to jackson even, i was in kalamazoo this morning and didnt even care much for that drive


did you guys re-use the slant 6 shaft?
will that hold up to the power of the 360?
 
silly question about the air cleaner
i really like the looks of the dual snorkel aircleaners but they seem to want more for those then i paid for the entire engine

so im going to see if it would at all be possible to cut down the stock unit and make it fit (i know, the stocker only has one snorkel, but still)

so, how tall should a 360 air cleaner be?
 
got a chance to run a compression test on here and this is what it

1:120
2:120 (105 the first time i tried it, then 120 on the second try)
3:110 (107 the first time i tried it)
4:130
5:135
6:135
7:125
8:128

on a side note, i just realized i was supposed to keep the butterfly valve open, ill test it all again later with the valve open but these readings are with it shut

does that make for a useful reading at all ?
 
so, question about the cam, im sure it is stock since the motor came from a motorhome
i would like to get something with a little more performance and maybe a nice rumble at idle

ive been told the oil pan needs to come of to swap out cams and since this is a truck engine i might as well do it while im swapping out oil pans

now, here is my issue, i do not know if this motor will start on the first crank which may end up playing havoc on the break in period
so, what is it am breaking in?
the cam?
the springs?
the rockers?
the whole valvetrain?

if i find a used cam do i still need to go through the break in procedure?
and what cam will work with my stock valvetrain?

thanks guys
 
That engine is a real low compression engine (probably in the high 7's to real low 8's) so your not going to be able to put a very big cam in it or it'll just be a rough idling pig. As far as what'll work with the valve train, don't even think about using those old valve springs with a performance cam of any size. The original pushrods and rocker arms will be ok to use if their in good shape but the springs will for sure need changing. That engine probably has rotator type spring retainers on the exhaust side that will definitely need replaced. I always replace everything with quality performance parts cause the stock stuff wasn't good for much other than what it was designed for.

As for break-in your breaking in the cam to the lifters. I personally don't like to use used cam and lifters with all the trouble were having nowadays with flat tappet cams.

Summit has a couple cam kits that are decent in mild performance applications and dirt cheap. Here's links to them

http://www.summitracing.com/parts/sum-k6900/overview/make/dodge

http://www.summitracing.com/parts/sum-k6901/overview/make/dodge

The first cam (K6900) will probably sound like a stock cam but it'll give you some more midrange and top end power. The second cam (K6901) is the largest I'd consider for an engine with low compression. It should have a somewhat racey idle and will definitely wake it up in the mid range and upper rpm. But it will probably sacrifice some low end torque.

If you don't mind spending a little more here's a comp cam that's similar in specs to the summit K6901 but it's ground a little more aggressive so it should make similar midrange and top end power and more low end torque. It won't idle real racey but you should hear it

http://www.summitracing.com/parts/cca-cl20-222-3/overview/make/dodge

That's the biggest I'd go due to low compression and the limitations of the stock pushrods and rocker arms. The good thing is with any of those cams you don't have to worry about spending big bucks on high dollar parts (titanium retainers/locks, etc). Just good aftermarket perf parts will do.

Lets go back to cam break-in. It's absolutely imperative that it fire nearly immediately or it'll wipe the cam lube off the lobes and risk failure. To make sure it fires immediately you need to make a check list and check it at least twice.

Before you even crank the starter you need a known good working carb full of fuel and have the idle turned up quite a bit because on break-in you want it to idle at least 2000 rpm, and you need to know positively the ignition circuit is functioning properly and the timing has to be pretty close. Naturally it has to have plenty of good oil in it. By good oil I mean something like Valvoline VR1 or a similar oil that has plenty of ZDDP. Several companies even make specific break in oil. The coolant system has to be properly sealed up and full. And the battery needs to be fully charged and have a good starter so it kicks over good. It's always a real good idea to have a helper that is mechanically knowledgeable in cam break-in and maybe even a spotter to watch under the car to make sure you don't have any leaks.
 
That's not a bad cam but why buy a used cam when you can buy a new one for just a little more? I have seen so many flat tappet cam failures the last few yrs. I won't use a used cam unless it's going back into the engine it came from. If you want to get away from the break-in procedure and good performance buy a roller cam. They cost quite a bit more but you don't have to use special oil or break them in and they generally make quite a bit more power
 
I still stand by my original assessment. Take the time to collect all of the appropriate parts, and do it right the first time. Decide what you want and pick away at it.

I have an engine on a stand that's been hangin there for a few months. I have another that's been sitting there for a couple of years.

I'm collecting parts to do a moderate build on the one, for short term. The other one will end up being stroked at some point.
 
Bad Sport said:
I still stand by my original assessment. Take the time to collect all of the appropriate parts, and do it right the first time. Decide what you want and pick away at it.

I have an engine on a stand that's been hangin there for a few months. I have another that's been sitting there for a couple of years.

I'm collecting parts to do a moderate build on the one, for short term. The other one will end up being stroked at some point.
Click to expand...
^^^^^^^^^^^^^^^^^^^^^ Best idea ^^^^^
 
Bad Sport said:
I still stand by my original assessment. Take the time to collect all of the appropriate parts, and do it right the first time. Decide what you want and pick away at it.
Click to expand...

That's pretty much what I am trying to figure out, I know I want a moderate street car wit good but controlabe power that is dependable and sounds mean

I haven't really figured a budget but I don't want to spend more then I have to.

It's been a long time since I build my last engine and that was a 4 cylinder diesel so I'm a little rusty on the whole subject
 
Bad Sport said:
I still stand by my original assessment. Take the time to collect all of the appropriate parts, and do it right the first time. Decide what you want and pick away at it.

I have an engine on a stand that's been hangin there for a few months. I have another that's been sitting there for a couple of years.

I'm collecting parts to do a moderate build on the one, for short term. The other one will end up being stroked at some point.
Click to expand...

This, is great advice. Time costs you nothing, and you get better prices on used / new parts searching with patience. Impulse buying , costs too much in the long run ( j.m.o.).
 
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