Toyota Celica Supra Forum banner

newbie needs 5mge info

2434 Views 17 Replies 11 Participants Last post by  supracharged
I require some information on an 83' 5mge engine which I recently pulled for a swap into Toyota 4x4.
I have heard various rumors and suggestions from well-intentioned, but uneducated individuals (read: backyard V8 builders); so I decided to post my questions here to get answers from the guys who arguably know more about these engines than the engineers who designed them.

The engine was a strong runner in the car, but it is getting a complete tear-down and rebuild anyway. I need a few extra ponies from this engine (15-20 hp would be ideal); however reliability and gas mileage are more important to me than performance, so wild modifications are out. Bottom end torque is also more of a priority than top end power. I intend to port/polish and add a header (best brand to use?), but I have also heard that swapping in 84 + pistons into this 83 motor will free up a few horses as well: is there any truth to this? Is there a particular brand of piston I should use, or just pull pistons/rods from a 84+ junker?
Also, if any fellow canucks want to suggest places to find quality parts here in the "true north" it would be appreciated.

Thanks to all who reply.
1 - 18 of 18 Posts
Too bad you already have a 5M. A 6M would be the ticket. 45 more ponies and about 50 more Ft/Lbs @ 3800 RPM as opposed to the 83 5M's torque at 4400 RPM.
Stay away from the P&P as you will loose low end for a gain in top end. The 84+ pistons have higher CR (9.2 vs 8.8 ). Since you arent upping power too much stock pistons would do just fine. You can shave the head some for some extra CR while you're at it. Header/exhaust is a good idea. Doug Thorley is tops in my opinion for headers. And I totally agree, 6m woulda been the way to go.

actually a thinner headgasket would prolly be a better idea. shaving the head makes it less likely in the rare chance the engine may overheat and the head warps i can be machined and reused again. you might want to replace the valvesprings while your into the head. that will help the engine so much it's unreal. and i eleive the pistons being changed out should bring you up to about 156hp...i know later 5ms had 156-160 depending on your source. i always use the smaller number so i'm not overestimating anything.
maybe even add an open air filter and a CAI from :wink:

Talk to Aaron, he is a good guy
If I am not mistaken the later 5m's also had a different intake runner configuration (d shaped not round) adding some hp. If you can use the later intake it might be worth while. But, I am not sure if it is a direct swap. What year 4x4 are you putting the 5m in?
The three best mods you can do to a 5M:

1. Breathing Mods
2. Breathing Mods
3. Breathing Mods... via a turbo.. LOL

I bet your noticing a pattern... The 5M responds inordinately well to breathing mods. Open up the intake with a freer flowing intake and filter, and then let her exhale thru a header and 2.5" exhaust, and you'll notice more low end power, and she'll pull harder, longer thru the revs...

The 84+ intake does have D shaped runners. I am sure someone has dynoed the same motor with both set-ups, but I've never seen any numbers on it to give an exact effect... but the Seat-o-the-Pants-o-meter says its a noticable gain... and it IS a direct swap.

Stock Pistons from an 84+ motor will do find for puttin ya at the 9.2:1 compression ratio. AS for head shaving/thinner Head Gasket, I would be a bit leary of that. The 5M is a Non-interference motor, and changing the "Squish" area the Piston has will definately make it an Interference type motor.
See less See more
i'm from up north... how far "up" are you?
Yes, it is unfortunate I did not know about the 6M when I started this project, however, the 5M was given to me for free so I probably would have used it anyway (actually, the whole car was given to me, but why split hairs?).

Racefiend, I am a little confused by the p&p comment; does a p&p treatment not allow an engine to breath better at all rpm levels? I was always under the impression that a p&p improved horsepower and torque across the entire rpm range versus just the high-end.
Jbrody44, the 5M is being transplanted into an 84' X-tra cab; my trusted and reliable workhorse for the past 14 years. Thanks for the intake suggestion, I have heard of it before but was unsure of the results so I did not pursue the issue any further. Now that I have confirmation I will dig up a newer intake for my engine.
Supra Bob, I very much appreciate your input. So, if I understand correctly 84+ pistons will give me a few extra ponies without any problems? What about the rods, do I have to swap those over with the newer pistons or will the ones in the 83' suffice? As for the head shave, I never seriously entertain head shaving, but thank you for the warning anyway.
Slip, I am located about 6-7 hours north of you (Willie's Puddle). However I visit the coast often, so if you have suggestions about where to shop for 5m parts in Van or western Canada I would be greatful.

Many thanks to all who have replied, please keep those comments coming! I figure the more info I can gather the better off I will be.
See less See more
That will be an awesome truck with the 5mge. I have a '90 x-cab with 3.0 litre V6 (3VZE) and I can tell you that the 5mge has way more torque and balls than the 3vze. The 3vze has served me well and is a great worker, I even plow snow with it, but the 5mge would be great in the truck. Maybe if the 3vze ever dies I will go that route myself as I just can't ever see getting rid of the 4x4. Let us know how the project goes and some pics would be great!

Check under the for sale section under the post "intakes" Shawn P. or "junkie" has some d-shapes intakes for sale.
Well, I did a very mild P&P on my 5m, and there was a noticable loss on the bottom in exchange for some nice top end. As I understand it, it has to do with air velocity. At lower airflows the head is not as much of an obstruction compared to the benefits of higher air speeds. However, as the airflow increases, the restrictive ports become a porblem. When you P&P, the decrease in air velocity will casue a drop in power down low because the port was not that restrictive to begin with at those lower airflows.

from what i understand, what hurts tq the most is port matching the exhaust to the manifold. this allows reversion to occur and hurts power. also, when you gasket match the intake side, you only go about 1/2in into the head then taper it to the stock size and polish it. then smooth out the short side radius on the intake and exhaust, and unshroud the valves and clean up the bowl.

It is nice to hear approval from someone who owns and drives both types of vehicles. At least you are fortunate enough to have the 3vz in your truck, I only have the 22R....and its carbureted (now you know why I want the 5m)! Yes, I will post pictures as the project rolls along if there are people interested. Things are on hold at the moment due to winter temperatures....

Racefiend, thanks for the info; I guess I will take your word for it since you have experienced the results first hand. I will have to do some research into this as now you have roused my curiosity :)

williamb82, thanks for the tidbit regarding the exhaust matching.
I would be very interested it pictures because it has crossed my mind more the once about doing what you are doing someday.
For those of you who are interested, there is a link below to a site describing in some detail a 5mge swap into a mid 80s' Toyota 4x4.

Can anyone confirm for me the question as to wether 84+ pistons can be used in an 83 block with the 83 rods? I.E., can I use 83 rods with 84+ pistons, or do I need the 84+ rods as well to make the swap work?
yes they can. it will raise the compression from 8.8:1 to 9.2:1. it will raise even more if the head and block are shaved. the rods are the same.
Great, thanks very much for confirming that little bit of information for me!
1 - 18 of 18 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.