Buick 231

[FreeBird]

Hi, this is my first post on this forum, so maybe I should introduce myself a little. My name is Hans and I'm from The Netherlands. I don't own a H-body, but an A-body (1975 Buick Century GS). But it has the 231 odd-fire V6 and that is the reason I stopped by here. Came across this board and saw there was some knowledge here on this little engine. And I thought I'd break down the door with a few questions right away hehe.

Mine is still bone stock. But my plan is to convert it to 4 barrel. Already got me a Holley intake (300-22, 'street dominator'). Still need to find me a good Q-jet carb. By the way, if you are looking for another intake for your 231, look at this: http://forums.off-road.com/jeepster-ame ... ifold.html

But what other things can I do to gain some more power? Right now it has one single exhaust pipe going to the rear. That will soon be two. So maybe that will make a little difference. But since I need to pull my intake, I was thinking of pulling off the heads aswell. But I already read on here that heads don't really interchange. So what can I do with these 75 heads? Off course I could clean everything, and maybe rebuilt them with some new parts (valve seats etc.).

My TH-350 is acting weird. Probably anytime soon we're gonna pull that from the car to to check it out and maybe getting it rebuilt or putting another used one back under the car. But with the tranny gone I was thinking of pulling the engine up a little so I can take the oil pan off. And replace the piston rings too.

Does this all sounds like a good idea to you guys? Or would you just drop in a Buick 350 lol? (kinda going back and forth on that too)

But my main question is which internal engine parts really wear after 30+ years and cause power loss? Piston rings, valve seats...what else? New hydraulis lifters might be a good idea too. Is there anyway to get more compression out of these engines? Milling the heads? Flowing ports?

Oh one more thing, this link might be interesting to some of you: http://www.earlycj5.com/tech/engines/225/index.php

[PeerStalkHawk]

Hello Hans, nice to meet you from so far away. Very nice and unique car you have there. I see you have the odd-fire 231 in yours. That is a heavy car so I see your situation. It will take a lot of work to get an improvement over what you have now but it is possible. It would make most sense to build your motor for max. torque improvements to get the weight moving. If you want to keep it simple and economical here are some tips. The factory induction in one of the weak links in these engines and your idea of a better intake and carb will make one of the biggest improvements. The Holley intake you have actually works well and I have used it before on one of these engines. Try to get a carb in the 450-500 cfm range. Make a ram-air/or cold ducted air setup to your carb. For the heads install bigger valves such as the later 1.71 intake and 1.5 exhaust and get some mild porting done(mostly to clean up casting imperfections). Mill the heads down about .030 and try to use the thinnest head gasket possible. Most aftermarket are .020 thicker than stock costing you some compression if not accounted for. Get a mid-level performance cam that makes good torque and power from 1500-5500rpm or so(approx.220-230 @.050 and 110-112 separation). Use new Buick(not Chevy) lifters and replace the timing chain for sure. It would be better if you could overbore the engine at least .030 and it would add a slight increase in compression when combined with the milled heads. Mill the block .020-.030. Get at least a booster/wear plate for your oil pump. It will help improve oil flow. Port-match the exhaust manifolds and entrance area (or get some headers). Run your dual exhaust idea with at least 2-1/4" pipe on each side. If you take out the transmission then put in higher stall torque converter such as 2700-3000 stall(10 inch). Put a 3.42-3.73 gear in rear. The last two things are really big improvements and would be quite noticeable on your car. They are needed to get the most out of the engine combo. Set your timing for about 14-15 degrees initial and 34-35 total and it will run on regular octane pump gas if you just milled the heads and block. You would have about 8.5-8.8:1 comp. ratio with a stock piston and would make close to 200 horsepower. This would move even your heavy car much quicker and will probably even improve your mileage a bit too. Your engine will match or exceed the performance of the stock factory smog era Buick 350!!! This was just a mild build idea Hans that would work easy. More can be extracted but will take more parts/time and money for gains. Your car will perform better than the factory v8 in your year of car and shave 2 or more seconds off your stock quarter-mile time. It would make a very big difference if keeping your v6. Hope the info. helps and good luck Hans!!! Also your car is similar to the 1975/76 Buick Century pace cars in Free Spirit or turbo v6('76) form-really rare. Take care....Dean.

[gerbsinmd]

Dean, That recipe sounds a lot like what Kenne-Bell recommended back in the 80's - 90's for that engine. They had very impressive results using that recipe. I wish I would have had the $$$$ back then to do that.

[FreeBird]

Hi Dean, wow that sounds like a very interesting setup! Yes the car is kinda heavy and in my opinion underpowered with such a mild smog V6. I'm not sure how far I want to go though. I wasn't planning on really hot rodding this engine to the max. The 4-bbl conversion will defenetly happen. Also dual pipes. I know a guy who has exhaust flanges for this engine, this way I could make my own set of headers. The thing is that they don't offer aftermarket headers for these early odd-fires. Maybe I'll go with that. I know a few people who can weld real good and know how to bend tubes and all. I think making ourselves some headers can be done. Oh I forgot to mention that my car has a posi rear axle (factory). I don't know any of the numbers.

That Holley intake I have is new by the way. It has holes for the EGR valve and one at the front for some vacuum switch (for the EGR system). But those holes are all blocked off. The color is a more darker grey color than the rest of the intake. Why is this? Is this stuff 'softer' so you can take it out and open up the holes? I'm not going to use EGR system. All power robbing stuff is going out the door!

About the carb, I'm still looking for one. I don't know that much on carbs, but the only ones I know at least little about are Quadrajets. And I'd like to go with a spread bore design anyway. Gas mileage is a bit of deal here also, gas prices here in Holland are way higher than for you guys in the US (we pay about 3 times as much for the same amount, when you convert litres to gallons and euro's to dollars). Otherwise I'd just through in a 350 or maybe even a 455 haha. It would be really cool to get some performance out of this V6 and still keep a fairly good gas mileage. Most Q-jets have more than 450-500 cfm's. But I've been told a Q-jet hardly ever 'overcarbs' an engine. I could use one from a Chevy 350 (most Chevy Q-jets have the side fuel inlets, other wise it would probably interfere with my thermostat housing). Only thing would be that I might need other jets (if I really want to fine tune it). Cold air induction is a good idea. I should run a tube (or tubes) all the way to the front to pick up cold air (I'd like to use the original style air cleaners anyway, instead of those chrome open air cleaners, you would be just picking up warm air).

Milling the heads would really be cool. Might go for that. Milling the engine block is nice too, but for that I would really need to torn that whole engine apart (right?). I checked the stock sizes of the valves and yes the ones you mentioned are bigger. They were used in 1979 (and up I quess). The difference isn't that big, but it would require work to the heads right? To the valve seats I quess? I'm famillair with engine tech, but when it comes to high performance upgrades I don't know everything. What exactly it porting the heads? Is that making the ports bigger so they flow better?

About ocatane, overhere we have regular gas with 95 octane. ''Super'' is 98 octane. I have a feeling that is a lot more than you guys have? Is that correct? Would it make a big difference?

Still not sure if I want to go with a new cam and more things you mentioned. It really is a nice 'recipe' and would love to go that far. But I just have to see what my paycheck allows hehe.

About my transmission, I'm thinking of using the TH-350 on my 1974 Monte Carlo. That is my other car (pretty much the same type of car as the Buick, also A-body). But that one is undergoing a major resto. I'm working on the floarboads (man those were/are bad). Flintstone style still (cut out all the bad areas), but I'm busy welding in new pieces. But since I need to weld from the underside of the car too, I need to take the exhaust pipes from the car. And probably the tranny too (its all in my way). I would need an adapter plate of course for using that tranny. Is using an other converter making a big difference?

Yes it is pretty much the same car as the Free Spirit pace car. But those have a different roof style. At the back I mean. More like the Monte Carlo design. Mine is the 'sports coupe' style. As far as I can tell it is an original GS (wich is kinda rare). Here's are pics:
http://s91.photobucket.com/albums/k304/ ... tury%20GS/

[PeerStalkHawk]

Hans, you do have a very nice car in those pics. And yes, those cars are fairly heavy(4000 lbs. or so?). The octane of gas you mention does play role in what can be done and I am not sure if your gasoline octane is calculated the same as ours here but regular in Canada/U.S. is about 87 and premium is about from 91(average) to even 93 in some places. It is figured using an average of two methods Ron+Mon/2. If ecomomy is of concern do the v6 and it will work well and still make a big difference. If all out performance is your goal then sure the v8 is better yet. As you know, the early odd-fire v6 is basically 3/4 of a Buick 350. A Buick 350 would be also good choice to modding as they respond very well for a smaller v8. The point is that in the 70's most engines period wake up a lot with mods because they were very choked up do to emmission concerns and are very underpowered. Because of that any regular modding really works well. As for compression you could run up to 9.5:1 or slightly higher if your fuel was truly 95 octane or higher but it requires new higher compression pistons or a lot of milling. Overboring the block helps to add comp. ratio slightly too. If .030-.050 was milled from head and block it would also help to make up for thicker aftermarket head gaskets. Milling too much more might require that the intake would then need to be milled to fit. Also that slight amount will keep your pushrod geometry the same as usually the lift at valve is less than theoretical rating. The valves are really important and the small port '75 heads are same as mine in my '77. Larger valves really can give much more flow and get them cut by someone who does it often or can flow the heads. There are several places to buy aftermarket lager valves such as TA Performance, Manley, etc. or just cut down later v6 valves. The bigger the better. The low port heads can flow as good and better after than later high port with some porting or mild polishing and later size valves. If your not sure get a professional to do it because it does make a difference. If you pull the heads put in a cam as it can also give you a large gain. The Quadrajet carb is very good but make sure it matches your application. The odd-fire engines like leaner jetting at wot than later even-fire and has to do with reversion pulsing. Another excellent carb for max. fuel economy is a Holley 390 four barrel. They are around and use vaccum-secondaries which will need to be tailored for your situation with the spring in diaghram. I have used one on one of my cars and it ran very well even in cold weather when starting. It is the smallest carb would use on yours and will give you best fuel economy over the others. A fellow at Queen City Performance in Regina,Sask. rebuilds Holley carbs to like new(or better) condition for very a reasonable price. You seem to know a lot about engine tech so lose the EGR for sure but use the PCV on intake or you will have blowby out your seals. And remember that with whatever engine you use the converter and gears are a big help to get your heavy car moving. Do them if you can Hans. I have worked on the Buick v6 quite a bit and they can work well if tuned properly with matched parts. They need better airflow and can give decent torque for their size. It would be neat to see how it works in a car as heavy as yours as you have one of the heaviest cars it was put into. A modded odd-fire with dual exhaust sounds unique and like a v8 really. Will talk to you later Hans and I will check that octane difference out.
...Dean

[PeerStalkHawk]

Hans, the general info. seems to suggest in in Europe and other areas outside North America that gas in primarily rated in mostly ron there which is more a measure of resistance to detonation and pinging(although very useful for performance engines). Here it is an average of Ron and Mon which suggests just Ron gives it about 4 octane higher so 98 octane there is about 93-94 octane here. Yes, you do have generally higher octane as the "norm" over there. So your 95 unleaded premium is about like our 91 here and your "super 98" is actually leaded!-(lucky you guys!!!). I checked a few sites that agree on this. Its still as high or higher octane than our better premiums and leaded fuel is great for performance and economy. If using the higher octanes, you could try adding a few degrees timing and you will extract some more power. It may not audibly knock however. Use the min. octane that gives you best performance and mileage for the price.
Also, if you do get four barrel carb make sure its newer or overhauled well because the idle and air bleed passages or other parts can get dirty and gum up giving many shaking problems or stumbles that won't just adjust out otherwise. For the cold air setup you can cut and weld an extra snorkel to the base of a four barrel housing or weld two 3 inch tubes on each side to clamp hoses to and put in a low restriction filter. The factory snorkel can't usually feed much more cfm than even the stock engine consumes......Hope that helps Hans.
...Dean

[FreeBird]

Dean, thanks for clearing that octane thing up! Makes sense. My Buick was built in Antwerp, Belgium. It has always been in that area. About 8 months ago I bought if from a guy near Antwerp and imported it here in Holland. This engine has always seen 'our' kind of gas. My 74 Monte Carlo is from Texas (imported it myself in 2005). It runs fine overhere on 95.

I'm still not sure what kind of carb I want. Either a quadrajet or a Holley 390. I've heard other people about the Holley 390 carbs too. They seem to perform well on these engines. I think I might go with on of those. I've seen them on Ebay, but they are kinda expensive. In used condition they are affordable. But I would want a 'normal' one, not modified for racing (circle track, NASCAR or whatever). Would that be a good idea to buy a used Holley? Of course I would like a new or rebuilt one better, but they are expensive.

Dean, could you explain to me how cam specs work? I'm getting it a little, but not totally and that doesn't make it easier to choose a correct cam. You know the whole lift and duration thing and 'advertised duration'. Take this cam on Ebay for example: #290161360030
It pretty much meets the numbers you suggested. But it says '1977-1990' and 'Even fire with integral distributor gear'. So I quess it won't work on my 75 engine though (right?).

About bigger valves, I read that the stock sizes for my engine are: intake: 1.625, exhaust: 1.425. The ones you suggested (1.710 and 1.500) are just slightly bigger. Does this require a lot of work to the heads? If you port the heads, I can see why you would want to work the intake ports. But how 'bout the exhaust ports? Keeping them stock?

Yes I will keep the PCV system, nobody wants blowby gasses in their oil hehe.

Oh one more question, I've seen these headers on Ebay for a while now: #230179931987. It says '78-87', would it be an idea to have the exhaust ports matched to these headers? I might be able to get the correct flanges though for my 75 heads. I was thinking of cutting of the flanges on these headers and weld on the correct ones (that way the ports won't have to be changed).

Hans

[PeerStalkHawk]

Hans, the smaller primary barrels on a four barrel will give better fuel metering and signal for better low speed response. A holley 390 is kind-of like still having your stock two-barrel responsiveness and mileage at part throttle/low speed but gives extra airflow according to demand when needed up to the full 390cfm by using vaccum operated secondaries. Your stock carb is approx. half of the 390 and not enough for a modded engine for maximum performance. A good used carb that was rebuilt properly can be just as good or better than new in that it can be calibrated and set up just for your application. However, a Holley 390 is close new out-of the-box. Another good carb is an Edelbrock 500 cfm which is common and is also more than enough airflow but uses the mechanical secondaries which open more as the front barrels open wider in combination. They are reliable and very easy to tune. I also used an Edelbrock carb and liked it. As for the camshaft, idealy you want the valves to lift as high as possible and stay open as long as possible for maximum performance but the low-speed driveability and average used rpm range of the engine also dictate the best cam profile. To get better fuel economy and lowspeed torque, a sacrifice between the variables is made. Your car would benefit from a camshaft that gives good grunt off the line along with some good mileage while still able to give higher rpm power later on. The .050 duration is just a standard way of measuring how many crankshaft degrees the valve lifts for as the .050 is when usually the valve starts to give any measureable airflow. The 110 or 112 separation dictates where and for how long peak cylinder pressure is in effect. A 112-114 gives a wider torque and power band over a longer rpm range than say a 110 which may give better peak pressure sooner or in a narrow range and end quicker. Also the amount of time both valves are open(overlap) effects your smoothness but can pull air or scavenge it at higher speed if everything else matches flow. You will need slighly higher compression than stock(about 8.5:1- 9.5:1) and a lower rear gear and higher stall converter to make it work best. For your car, Flatlander Racing online has two good cams-one by Schneider's Racing(part #05085 with 270/270 or 218/218 duration @.050; .480" valve lift;110 separation;and power from 1500-5000rpm). They also offer an Isky Super Cam (#117126 with 262/262;.208/.208 @.050;109 separation;.465" lift;and power from 2000-5500rpm). They would work very well for your purpose or find a similar profile if you can. You have to make sure you get a '75-'77 odd-fire cam and yours has a take-a-part distributor gear and key so it just separates and you put the parts back on the front of the new cam. Even-fire was all one piece(integral). Also the valve guides must be cut to accomodate camshaft lifts over .420" so get it done if you can to prevent a problem. The bigger valves can easily be installed into your heads with a bit extra work by any good engine shop. Aftermarket valves can flow better and also the proper valve cut angles can increase flow too. The intake valve work is much more important than the exhaust which doesn't need as much work to flow okay. You can fabricate something I'm sure for exhaust with welding and it should be adequate. I see your car may have a 2.32 rear gear so a 3.42,3.73, or very close gear would be a huge improvement and your rpm won't be too bad at all with your larger tires at highway speed(maybe 2600-2800 rpm or so) with the TH350. Accu Auto Parts online has many brands to choose from for cheap. You might actually improve mileage along with power because you don't have to "stab" the gas so much or lug the car to get it moving. The simple engine combo and gears will make it move around a lot easier even with that v6. Hope it all helps you Hans.
...Dean

[FreeBird]

Dean, once again thanks for the extra info, tips, specs and part numbers! This is helping me a lot! Unfortuntatly I can't dig into this just yet. I quess we need to pull that tranny first and see what is wrong. First things first hehe.

More and more I'm thinking of going with a Holley 390. I like the fact that they have an electric choke and vacuum secundaries. And I think this relatively small carb will do fine on my engine. That Schneider cam that Flatlander Racing offers is very interesting! Their Isky cams are pretty expensive. From the two I'd like the go with that Schneider cam. The specs of that cam are looking good I quess. That is probably what I need. Thanks for the explanation of cam specs by the way.
In what way would the valve guides need to be cut? I didn't quite get that part. I have a feeling the heads will be the most costly procedure hehe (they will also make the biggest difference I quess), About my rear gear, all I know is that it is a posi rear axle. But I don't know the gear ratio. I should open it sometime and count the teeth of the ring and pinion gear, to determine the gear ratio. By the way, parts like this: 150170970477, is that something I could use? I have most likely a 8.5" rear, but I'm not totally sure. I think I will try that thing with the headers. Would be cool to have headers too.

Hans

[cammerjeff]

How do you tell the CFM differance on a Holley? I have an extra Holly Carb that is suposed to be a 390, came with Kenne Bell Intake I bought at a swap meet earlier this year.
It has Vacuum secondaries has a single accelrator pump, electric choke, the numbers 8007 & 0951 stamped on the choke housing (primaries), 103 samped on the primary butterfly's, 66 or 99 in ink on the drivers side choke housing. And 7800 3 on the bottom of the trottle plate. It is for sale for $50.00 USD plus shipping. If any one is interested. I can E-Mail pic's also.

[flracer]

Jeff,



The 8007 is supposed to be a 390 cfm according to rebuilders on ebay.



Richard

[PeerStalkHawk]

Hans,
I think the Isky cam section shows them for pretty cheap by themselves but also shows the complete kit which is what looks so expensive. Just look over to the left of the kit for just the cam price. For off-the-shelf cams they both look good. Schneider Racing Cams are good to deal with and knowledgeable about the odd-fire engines so their cam would be a really good choice. As for valves, the main three angles can be cut in such a way as to increase flow. The top cut is the lip or edge of valve area;the seat is the area the middle cut area and the bottom is the angle going towards the stem. For a street-driven car, the cuts can help increase flow but you must leave enough seat surface area for wear and longevity as well. Aftermarket valves can be already shaped for better airflow and swirl-polished so they can be placed in the enlarged pockets or seats. They may be undercut/or neck down where the stem is narrowed for airflow in port area. Tulip-shaped exhaust valves work well. The aftermarket valves can be lighter, stronger, and also more heat resistant at high temps..They will help your engine rev up quicker and higher with less valve float later on. The choice of valve spring also plays a part but in your case the stock spring pressure will work okay or just go slighly higher in pressure if any(maybe 100 closed and 220 open). A good machine shop can install the larger valves in your heads and cut the valve guides for the higher lift cam. The heads will make a very big difference as they do hamper airflow in stock form. The bigger aftermarket valves will help a lot with some basic mild porting. For your intended rpm range that should be all you need to do and it will pull very strong within that range. The 3.73 gear is a great choice and you do have a 8.5"/28-spline rear. Will do some checking to see if the gears work for sure but the price sure looked good on that part#.

Jeff......Richard is right about the Holley 390 which is part# 0-8007 and also model#4160 with equal size throttle bores. It is a square-flange carb and has 1-1/16 venturis and 1-7/16 throttle bores. If rated by the two-barrel standard it would be about 550cfm!!!
.....Dean