225 gurus ?

Hi all.
Looking for some opinion and or advice.

I have been unsatisfied with the power of my 225.
Let me say I know its not a sbc and I am not comparing it to that kind of power.
but I can tell its just not up to snuff.
It runs out of power to low in the rpm band.

Heres what I have and have done too it.

When I got the jeepster it was running but I took it all apart right after driving it home the first day.
I tested the compression and it was 150 average on all cylinders.
So I decided to just add a few things.
I had a '75 buick doner car with a oddfire 231 in it.
I took the HEI off it and installed it it is the right dissy and is installed properly.
I added the crane adjustable vacume unit with the adjustment backed all the way out.
Plugs are .35 gap new wires
any thing I have touched has new parts cap plugs etc.
The carb was in better shape on the 231 so I rebuilt it and then discovered it wouldnt bolt on the original intake so I cleaned up the 231 intake and used it to.
Then I ended up using the oil pump cover off the 231 also as it was in better shape.
Rebuilt the oil pump add'd a new timing chain, water pump ect.

I adjusted the carb with a vacume guage and have power timed it for best perfomance.

It idles really good but doesnt rev up as freely as other 225 I have worked on.

I have been reading alot of old threads about 225's performance.
The only thing I have seen that makes me wounder was a mention of the 231 manifold not being a good fit and that it might cause flow problems.
Can any one confirm this or have any ideas or advice.

 

What intake gaskets did you use to put the 231 manifold on the 225? Felpro makes the best ones to keep the flow from being disrupted. I've found others to restrict flow. Also check the advance weight posts and springs in the distributor. Common for the bushings and posts to be worn causing issues. Also check the vacuum advance and make sure it isn't coming in too soon. You do have the advance hooked to ported vacuum and NOT manifold vacuum right? This is a common mistake and cause issues like you describe. I'd definitely look at what was suggested above as well.

 

I will try some new plugs with more gap.
I think I checked the wieghts but will look again
I do use a timing light and I think the cover I used is right and the first one was wrong I will re research that.
Cant remember which It was cast or bolt on pointer
The cam is an unknow was thinking it could be flat.
it is advancing and i have played with the crane adjustment no differance.
i am sure I have it on ported vacume but will double check.
The cap rotor wires and coil and plugs are new when I put in the HEI about 5000 miles ago.
I dont remember replacing the electronic deal under the rotor where it plugs in its name is on the tip of my tounge err.

I have a Qjet would that be doable with the right manifold?
I am thinking about the 252 comp cam and a intake.

The best way I can discribe it's lack of power is it feels abit like something is holding it back when it acelerates and at about 3000 grand it's done no more power not missing or running out of gas just flat.
I have driven a buddy's 225 in his cj 5 and it pulls fast and hard to maybe 4500 rpm he does have a cam of some kind in it.
And a 2 b carb he had a small holly 4b he couldnt get to run right so he switched back anyway mine's anemic next to it so I know its not me expecting more than normal

I guess I will try a minor tuneup and just see.

I dont remember which brand gasket I used I think I used the metal one with the pan in the valley.
I did block off the egr valve.

Rick

 

I thought the 231 was an even fire ??

 

Buick kept it odd fire for a couple years.
They used 350 pistons and came up with the 231 Oddfire.
They also started using the HEI then also with a wierd cap for the oddfire motor.

Then to smooth it out switched it to evenfire
from what I remember they also lowered the compression.
Probably helped with smog.
but the 225 has more compression and thereby more torque.

So the earlier say early '70's odd fire 231 have alot of common parts with our 225.
One thing that changed with the even fire was the heads which was probably where the compression went down with say smog heads.
All the gm lines were making those kinda changes right then.

I think guys go to a 231 thinking its a better perfomance motor and then can be disapointed if they dont take compression into consideration.
I bet there is a good combo of 231 and 225 parts to make a good jeep motor.
The problem I see is Buick was making small changes all the time so you have to know exactly what parts would work well together.
it would be cool to have a list of wreckingyard parts to assemble a lower budget power plant, no expensive machining involved.

I think you want the 225 flywheel and maybe a 231 odd fire block and better compression heads 225 or shaved oddfire 231's ? 252h cam etc.

Of course if you did an evenfire then FI would be a no brainer.

I like my 2b it doesnt flood till im almost vertical, If I went 4b the only one I like is the Qjet but is that to big

Rick

 

"I think guys go to a 231 thinking its a better perfomance motor and then can be disapointed if they dont take compression into consideration."

Yup. Dunnit. Very disappointed. Should have kept the 225. It ran way better.

"I bet there is a good combo of 231 and 225 parts to make a good jeep motor."

A guy told me to put either, the 231 OF heads on the 225 or, vice versa. I forget which. It would make sense to me, to use the 225 heads on the 231 but, I'm not sure. I thought he said to do the opposite, 231 heads on a 225. Stinkin' bad memory. mehh

 

'77 was the transition year from odd fire to even fire. Early '77 231's were oddfire and last part switched to even fire. The 4.1l (252) Buick V-6's used in Regals and some other applications came stock with a Q-jet and worked quite well. A 231 with a properly balanced 225 Jeep flywheel works very well because of the inertia of the heavier flywheel. I like the lighter 231 flywheel in the '59'5 as I can rev quickly. I also use it for sand and mud, not just trail running. If it were simply a daily driver, used mostly just on trails or rocks, then the heavier flywheel is an advantage. The 231/225 debate will rage on as long as there are Jeeps. There are advantages and disadvantages to both. The 231 evenfire in my '5 when I first installed it, rebuilt, with a mildly hotter cam, and a few head tweaks netted 220 hp at the rear wheels on a chassis dyno. With a Rochester Dualjet carb...

The seriously built 225 in the Race Jeep was dyno'd well over 400 hp but was useless for the trail. Either motor is good for our application. It's just making the right tweaks and choosing the right parts. No different than any other motor.

 

231 heads on a 225. They flow better. Been too long so I'd have to look up valve size but I do remember the flow bench numbers were better on the 231 heads.

 

231 oddfire or evenfire heads? and anybody know about the compression effects when you go to 231 heads.
I dont know if the compression diferances between the 225 and 231 is in the head or piston deck hight??
I want to do the cam and could use the'77 231 oddfire heads I have, rebuilt first of course, also if you guys think it would payoff.
my jeep is a trail jeep.

I have a rebuildable Qjet off a 67 327 that I want to use then and just get a intake and cam.

The flywheel talk makes me wounder if my buddys 5 has a 231 with a lighter flywheel not a 225.
he didnt build it and it has all kinds off dressup stuff and is obviously rebuilt.

That might be why his revs so much more freely than mine.
Cant say if he has really any more power but his does rev up to 5000 no loss of power so there still is that with mine.

 

Odd fire heads. Even fire heads don't match up to the block and intake without some serious work, if at all. Nick, thanks for clarifying. Would the better flow of the 231 heads offset the difference in compression ratios? The 225 is like 9 or 9.5:1 and the 225 is, what, 8.0:1 or so.

 

Correct me if I'm wrong, but a heavier flywheel (like the one on the 225), would lead to a slower rev up, due to just moving more rotating mass. I wonder if mebbe your friend has the lighter flywheel, and you have the heavier......

That being said, my bone stock 225, before it dropped #1, would rev pretty good to about 42-4300, then the carb just couldn't flow enough to maintain above that, like a built in rev-limiter. I pulled the stock Rochester and put a Motorcraft 2100 on there with an adapter, and that helped a bunch, I could hit 5000 if I wanted to (although, I'm not sure I would ever recommend it)

Edit: I need to learn how to read. You said you suspected your friend had the lighter flywheel. Sheesh. Reading Comprehension, it's a good thing.

 

I doubt it. The better flow would very much complement the higher compression ratio though.

 

What Chuck said. Pat Ganahl's book is THEE Buick V6 book. An excellent resource. Mine's............around.......here..............somewhere............