Dave, when dealing with a low compression engine, there are a few things to
keep in mind about engine modifications. The biggest one is the camshaft. Be
careful of the cam duration and also the lobe separation angle. These 2
factors are critical to cylinder pressure. The best way to cam these engines
is with a shorter duration, high lift cam. Also look for a camshaft with
110-112 degrees of lobe separation. Lobe separation is often overlooked in
cam selection, but it is critical. The higher separation angle will do a few
things. Fist, it reduces valve overlap, which is the time that both valves
are open during the exhaust stroke. The reduced overlap will improve low RPM
torque and idle quality, but at the expense of top end power. Bringing the
lobe separation angle down, conversely increases valve overlap which will
decrease idle quality somewhat, and also improve top end power.

A few other things to keep in mind. LPG likes high compression, so if you do
rebuild the engine, take that in to account. Your idea of aftermarket intake
and exhaust are also highly recommended, but again be conservative on
manifold runner sizes and header tube diameters. The smaller passages will
keep the air velocity higher at low engine speeds, which will improve
torque, drivability and efficiency. The Edelbrock Performer is a good
manifold choice for these types of vehicles. Keep the exhaust header tube
diameter to 1.625" and find the headers with the longest primary tubes you
can. This will improve low to midrange power.

One thing that might improve your situation very inexpensively is ignition
timing. Because of your low compression ratio, you should be able to
increase the ignition timing with the fuel you are using. Unfortunately this
is probably not just a "turn the distributor to advance the timing" fix, but
would probably require lighter springs and different weights in the
distributor. I believe Mr. Gasket still offers an AMC advance curve kit
which would fill the need pretty good.

I guess the timing would be the first thing I would mess with, because it is
the cheapest mod you can make, and next would be the headers and exhaust,
based on return of investment to power ratio. Again, just be careful not to
get too big on the tube diameters. Just keep in mind when selecting parts,
that your goal on a low compression engine is to keep the air velocities up
in both of the intake and exhaust passages. Do that and you will be fine.

Chris


"Dave Milne" <jeep@_nospam_milne.info> wrote in message
news:4EAqg.96270$wl.13244@text.news.blueyonder.co. uk...
> Well, here is where I got the info from:
>
> http://www.ifsja.org/tech/figures/engines.html
>
> 360 AMC V8 / OHV 90-91 144hp 280 lb/ft torque 2bbl Motorcraft.
>
> Compression ratio is only 8.25 : 1
>
> I guess I could try a new Edelbrock manifold and Performer carb.
>
> Dave Milne, Scotland
> '91 Grand Wagoneer, '99 TJ
>
> "Jeff DeWitt" <JeffDeWitt@nc.rr.com> wrote in message
> news:PrAqg.12113$so3.8013@southeast.rr.com...
>> I just did some digging and at least in 1998 that engine was rated at
>> 225 hp and 335 ft/lb of torque.
>>
>> Is that 144 with the LPG? It really does sound low.
>>
>> If it was mine the first thing I'd do is give that engine a through
>> going over including a compression test, timing and all that good stuff,
>> and make sure everything is in good condition. I've driven one of those
>> (would have liked to have kept it), and while it wasn't going to take on
>> any 5.0 Mustangs it had plenty of pep.
>>
>> If your timing is retarded, or if the timing chain was worn and jumped a
>> notch that might cause your problem.
>>
>> Whatever is going on unless there is something really wrong with that
>> engine it's going to be a LOT cheaper to fix what you have than spend a
>> bunch of money converting it to something else.
>>
>> Jeff DeWitt
>>
>> Dave Milne wrote:
>> > Yup, it is quoted *when new* at 144hp for a 5.9 litre 360. Which is
> pitiful.
>> > If it had a more respectible 280hp, that would be enough.
>> > I wouldn't have thought that a drag racer like yourself would be
> defending
>> > 31hp per ton ?
>> >
>> > Dave Milne, Scotland
>> > '91 Grand Wagoneer, '99 TJ
>> >
>> > "L.W.(Bill) ------ III" <----------@***.net> wrote in message
>> > news:44AA1A17.9C10DE75@***.net...
>> >
>> >> You running LPG and you complain saying your engine only has "50%
>> >>of enough" in subject line post: Wagoneer Engine Replacement Choices ?
>> >>What is this a blonde joke?
>> >> God Bless America, Bill O|||||||O
>> >>mailto:-------------------- http://www.----------.com/
>> >>
>> >>Dave Milne wrote:
>> >>
>> >>>I run LPG in my Wagoneer, so yes, I found it interesting.
>> >>>
>> >>>Dave Milne, Scotland
>> >>>'91 Grand Wagoneer, '99 TJ
>> >
>> >
>> >
>
>

 

Well, I guess I could try that. I wasn't hopeful I'd get very far with such
a low compression ratio. The 401 is a better engine as it has a steel rather
than cast crank, but getting one will be hard, and getting anything else
will be expensive.

"Mike Romain" <romainm@sympatico.ca> wrote in message
news:44AAD2F6.961D4300@sympatico.ca...
> So 'fix' it!
>
> Go for a larger carb or jet or whatever puts the fuel in, a high flow
> intake with a set of headers and a nice hot coil. Maybe you can Cam it
> too.
>
> There has to be a nicer or easier way to get oomph than replacing it....
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> (More Off Road album links at bottom of the view page)
>
> Dave Milne wrote:
> >
> > I'm sure it makes close to 100% of what it did new - it only has 62K
miles
> > on it. Just 144hp is 50% of what I'd like.
> >
> > Dave Milne, Scotland
> > '91 Grand Wagoneer, '99 TJ
> >
> > "Bret Ludwig" <bretldwig@yahoo.com> wrote in message
> > news:1152018373.690730.107600@75g2000cwc.googlegro ups.com...
> > >
> > > L.W.(Bill) ------ III wrote:
> > > > You running LPG and you complain saying your engine only has "50%
> > > > of enough" in subject line post: Wagoneer Engine Replacement Choices
?
> > > > What is this a blonde joke?
> > >
> > >
> > > It made power fine before.
> > >

 

Well, I guess I could try that. I wasn't hopeful I'd get very far with such
a low compression ratio. The 401 is a better engine as it has a steel rather
than cast crank, but getting one will be hard, and getting anything else
will be expensive.

"Mike Romain" <romainm@sympatico.ca> wrote in message
news:44AAD2F6.961D4300@sympatico.ca...
> So 'fix' it!
>
> Go for a larger carb or jet or whatever puts the fuel in, a high flow
> intake with a set of headers and a nice hot coil. Maybe you can Cam it
> too.
>
> There has to be a nicer or easier way to get oomph than replacing it....
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> (More Off Road album links at bottom of the view page)
>
> Dave Milne wrote:
> >
> > I'm sure it makes close to 100% of what it did new - it only has 62K
miles
> > on it. Just 144hp is 50% of what I'd like.
> >
> > Dave Milne, Scotland
> > '91 Grand Wagoneer, '99 TJ
> >
> > "Bret Ludwig" <bretldwig@yahoo.com> wrote in message
> > news:1152018373.690730.107600@75g2000cwc.googlegro ups.com...
> > >
> > > L.W.(Bill) ------ III wrote:
> > > > You running LPG and you complain saying your engine only has "50%
> > > > of enough" in subject line post: Wagoneer Engine Replacement Choices
?
> > > > What is this a blonde joke?
> > >
> > >
> > > It made power fine before.
> > >

 

Well, I guess I could try that. I wasn't hopeful I'd get very far with such
a low compression ratio. The 401 is a better engine as it has a steel rather
than cast crank, but getting one will be hard, and getting anything else
will be expensive.

"Mike Romain" <romainm@sympatico.ca> wrote in message
news:44AAD2F6.961D4300@sympatico.ca...
> So 'fix' it!
>
> Go for a larger carb or jet or whatever puts the fuel in, a high flow
> intake with a set of headers and a nice hot coil. Maybe you can Cam it
> too.
>
> There has to be a nicer or easier way to get oomph than replacing it....
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> (More Off Road album links at bottom of the view page)
>
> Dave Milne wrote:
> >
> > I'm sure it makes close to 100% of what it did new - it only has 62K
miles
> > on it. Just 144hp is 50% of what I'd like.
> >
> > Dave Milne, Scotland
> > '91 Grand Wagoneer, '99 TJ
> >
> > "Bret Ludwig" <bretldwig@yahoo.com> wrote in message
> > news:1152018373.690730.107600@75g2000cwc.googlegro ups.com...
> > >
> > > L.W.(Bill) ------ III wrote:
> > > > You running LPG and you complain saying your engine only has "50%
> > > > of enough" in subject line post: Wagoneer Engine Replacement Choices
?
> > > > What is this a blonde joke?
> > >
> > >
> > > It made power fine before.
> > >