350 Questions

[Olds luvr]

Hello Guys,

I will try to be as short as possible. I have an all correct 72 convertible Cutlass. When I bought the car I did not really drive it before taking out the motor and trans just to reseal the leaks with new gaskets and replace the basics (water pump, fules pump etc) The person I bought it from said the motar was recently rebuilt and when we took it apart you could tell it had been.

What I am noticing is that it is not as explosive from a dead stop as I would have expected. I had the carb stock Qjet 4 bbl rebuilt as well... but not happy with the place that done it and not sure if it was done right.

If I try to power break it will not light up the tires it will bog down and want to stall.

The acceleration is there when the vehicle is driving so I am a bit confused.

My question is am I expecting too much low end power that maybe it should not light up the tires from a dead stop or maybe a carb issue since it will not light them up from power breaking?

Thanks guys and sorry to wright a novel

[Oldsguy]

Do a complete tune-up or have one done right. Timing is very important and if advance isn't right on then you could have a boggy situation. This isn't to say this could be the only cause. The carb may have not been rebuilt correctly or it may have a worn throttle bushing that probably was not corrected during the rebuild. Quite a few variables, but a tune-up would be the first thing. And don't forget the dwell as well.

[Olds luvr]

So should I draw the conclusion that it should light the tires from a dead stop?

[Oldsguy]

Well, you said it was not as explosive from a dead stop. Sort of subjective, compared to recent performance? or compared to another Olds with a small block? Lots of variables. I have seen mid seventies Cutlasses with a small block able to burn rubber from a dead stop without "powerbraking", but then there is the road condition, and tires, and rear gearing. I can't tell you it will or should burn rubber from a dead stop but it should be powerful, it's a V8. And I think it should burn rubber if you powerbrake it. It definitely should not bog down on you.

[Oldsmaniac]

It should not in my opinion "light the tires from dead stop" with a stock 350. In 1972 compression was down and the engine was not as responsive as earlier small blocks. If the car doesnt already have dual exhaust I would suggest that for a little more kick. Also a lower rear gear ratio will give it more pull from a dead stop. Lighting the tires does not make the car quicker. Traction is a good thing, spinning tires isnt so good but still fun. My stock 66 Delta with a HC 425 and dual exhaust and non posi rear would only spin the tire now and then....I could not make it happen on command.

[Olds luvr]

Thank you for the replies and they make sense. It is good to know that maybe they should not light the tires from a dead stop. The car is responsive just does not like to take off from a stop sign or light. I was not sure if the stock small block with dual exhaust should or should not be able to light them up from a stand still but i guess I should be more focussed on it not from power breaking as it will just want to bog down and die. Which has me confused as it starts right up and runs great I just cant chew through these tires as I am wanting to replace them and what better way to justify that....

[captjim]

If it was rebuilt using the 22 cc dish cast replacement pistons, the compression ratio will be around 7.8 to 1 instead of the stock 8.5 to 1. This is a VERY common problem. Unfortunately, piston choices are limited and I bet that's what's in there. Can you do a cranking compression check? Disable the ignition, hold the throttle open and spin it 4 times. Lots of times the cam is too large because the cr ends up being so low. It should have EXCELLENT throttle response, maybe not roast them, but you should be able to do a butnout with street tires.

[texasred]

Might check the gearing, too. 2.78s do NOT make for a fun "exhibition of acceleration" experience.

C.J.

[88 coupe]

Originally Posted by Oldsmaniac

It should not in my opinion "light the tires from dead stop" with a stock 350. ........

Based on my own experience, you are correct.

Since it has been rebuilt, it's likely to have less power than it did originally.

Originally Posted by captjim

If it was rebuilt using ........

We do not know how the rebuild was spec'd.

Originally Posted by texasred

........ 2.78s do NOT make for a fun "exhibition of acceleration" experience.

Yes. another of the reasons why Oldsmaniac posted the correct answer to the actual question.

Norm

[captjim]

We don't know, but this happens a lot. You made the remark that "since it has been rebuilt, it probably has less power" What do you mean if not that the new pistons made for less compression. More mid range than off-idle, typical over-cam/under compressioned symptom. But obviously, do the normal troubleshooting and tuning things first. I would like to see the cranking compression. My 71 Skylark with stock 350 and 2.78s will go sideways from a dead stop. Engines that make a lot of torque and are responsive don't need a lot of gear, IMHO.

[88 coupe]

Originally Posted by captjim

........ My 71 Skylark with stock 350 and 2.78s will go sideways from a dead stop ........

Congratulations.

Norm

[captjim]

I see you act the same way here as you did on the other boards that you got thrown off of. I came here to try and help this guy, I'll go leave now and you can be the king-sh!t here.

[Olds luvr]

Guys,

Thanks for the tips, I do not know the specs to the rebuild as all I know is when I pulled it apart the cylinder walls, main bearings and everything else looked new with no wear but I am not sure who did it or if it was done to spec. The car is responsive just not a great jump from a stop. I will check the gears and hope that there is a tag on the rear end or is there another way to check? I do have new flowmasters that i want to have installed and alse want to go HEI over the current points system.

I am in seattle and if anyone knows of an olds guru it would be appreciated as from the calls I have made I am not finding too many people that specialize in SBO's or is that even needed.

Anyone have any other ideas for the car bogging down when trying to power brake?

Thanks again guys as me and my convertible appreciate it.

[88 coupe]

Originally Posted by Olds luvr

........ I do not know the specs to the rebuild ........

Doesn't matter. They have nothing to do with your problem.

Norm

[Redog]

All I did with mine was a new manifold, carb, and HEI. The car already had X pipe duals and I can smoke them from a dead stop.

My motor's a '68, so I think the compression is higher

[Olds luvr]

I thought of one mote thing....The detent (kick down) cable was replaced. If that was not adjusted correctly would that make a difference?

[captjim]

Originally Posted by 88 coupe

Doesn't matter. They have nothing to do with your problem.

Norm

Just for the record, are you saying that 22cc dish pistons down .040 with a .045 gasket won't effect low end performance, especially with a cam that is too big???

[88 coupe]

Originally Posted by Olds luvr

........ If that was not adjusted correctly would that make a difference?

No.

Norm

[88 coupe]

Originally Posted by captjim

Just for the record, are you saying ........

Read it again. This time, read what is actually there, not what you think is there.

Norm

[88 coupe]

Back on topic:

Have you followed up on Oldsguys suggestions, regarding a proper tuneup, in his first post?

Basic tuneup includes the following:

Check for vacuum leaks.

Check the vacuum and centrifugal advance for proper operation, set the dwell at 30°. Then set the initial advance at factory spec, for that engine. The initial setting is for use during the troubleshooting process.

........ but not happy with the place that done it and not sure if it was done right ........

Do you have any reason to believe it was not? If so, explain. If not, the carb is good.

........ or maybe a carb issue since it will not light them up from power breaking? ........

Two different issues. So far, there is no reason to believe they are related, in any way.

........ The acceleration is there when the vehicle is driving ........

Your “bog” is only there, at WOT, when the brakes are applied?

Describe your symptoms, as completely and as accurately as you can, IE: How much throttle when it starts? Does it recover? If so, how long does it take?.

Do not answer the questions directly, draw me a picture.

Norm

[Olds luvr]

88 Coupe.......I will try to draw you that picture as to what it does tonight.

Thanks

[jogo62]

chill out 88 coupe

[Oldsguy]

jogo62
Welcome to our site, why not introduce yourself to us? This thread is over half a year old.

[88 coupe]

Originally Posted by Oldsguy

........ This thread is over half a year old.

And his post has nothing to do with the topic.

Norm

[88 coupe]

Originally Posted by jogo62

chill out 88 coupe

If you wish to question/discuss the technical content of anything I post, do so. That is the purpose of message/discussion boards, such as this one.

If you wish to discuss my posting style, find the "offending" statement and "post the quote" in a PM, along with your objection to it.

If you are not prepared for a mature discussion, do not waste my time.

Norm

[rrielley]

I have a '72 Cutlass convertible with the L34 v8 and 4 bbl. Without powerbraking, she will indeed "light up" the rear tires. It's a horribly guilty pleasure, but it puts a big smile on my face every time.

[70Wcars]

I know this is an old post, but I just stumbled on it and will add one note that may apply to others with re-builds that have less than stellar low-end response.

Having torn down many Olds engines over the years, I have found a huge difference in Timing Chain and gear sets. Very often I have heard the same complaint of poor low end and when the question is asked, the answer almost always is that someone along the way had replaced the timing set. I take these apart and so-far all have shown the cam phasing to be several degrees retarded. By degreeing the cam to 2-3 degrees advanced, we are able to recover much of the lost low-end power.

I also agree with much of what has been posted concerning poor compression, 2-series rear gears, and perhaps a malfunction of the accel. pump from the carb overhaul. Like most have said, some 350 cars will indeed spin the tires and some won't.

Just my observations, but be suspicious of low-budget timing sets, and have the cam degreed if searching for top performance.

Hope some of this is helpful...

Danny

[GoldOlds]

Originally Posted by 88 coupe

Congratulations.

Norm

You seem to have interpreted cptjim's Skylark statement as bragging, which I honestly don't believe it is. I'm pretty sure he's just offering an example of his point that stock, nothing-special engines can light up the tires, even with highway gears. If you're going to accuse people of not reading your ENTIRE post before they respond to it, you should probably offer them the same courtesy.

- GoldOlds

[The_Jeremiah]

When is the last time your transmission fliud and filter have been changed ? if your tranny is all backed up you wont be able to do anything off the line, but after you get moving you will have the majority of your hp and torque back. from my experience, thats what it sounds like to me. wouldnt hurt to double check, or even just change it, it doesnt too long, less than an hour.

[88 coupe]

Originally Posted by GoldOlds

........ If you're going to accuse people of not reading your entire post before they respond to it ........

The following is from post #25 in this thread:

You should probably read it, before you start beating the dead horse.

Originally Posted by 88 coupe

If you wish to question/discuss the technical content of anything I post, do so. That is the purpose of message/discussion boards, such as this one.

If you wish to discuss my posting style, find the "offending" statement and "post the quote" in a PM, along with your objection to it.

If you are not prepared for a mature discussion, do not waste my time.

Norm

[88 coupe]

Originally Posted by rrielley

........ L34 v8 and 4 bbl ........

I am not familiar with L34. Is it the engine that came in it?

Norm

[captjim]

L34: Engine, V-8 4BC (350)
L-34 350 Cu. In. V-8 4 Bbl. (A Body) (1972)

L34 is just the option code for a 350 with a 4 bbl carb.

[88 coupe]

Thanks for the clarification.

Norm

[78cutlass]

88 coupe,
Your style of writing is confrontational (other threads). Relax dude.....

[88 coupe]

Originally Posted by 78cutlass

........ Your style of writing is ........

From post #25 of this thread:

Originally Posted by 88 coupe

If you wish to question/discuss the technical content of anything I post, do so. That is the purpose of message/discussion boards, such as this one.

If you wish to discuss my posting style, find the "offending" statement and "post the quote" in a PM, along with your objection to it.

If you are not prepared for a mature discussion, do not waste my time ........

Internet protocol. Nothing more, nothing less.

Originally Posted by 78cutlass

........ Relax dude

I am not a "dude".

Norm

[Olds luvr]

Hello Again,

I see that this is alive topic again and Thank you

70Wcars thanks for the idea on the timing set and the degree of the cam I will look into that. What timing set would you suggest and how do you change the degree on the cam?

Since this is an older thread and since I have not had the problem corrected as over the winter even though the interior was in great shape I have taken out the entire interior to do some things on the inside such as new(after market) panels to hold a 6.5 speaker to improve the sound quality as well as 6x9s in the factory location behind the rear seat as the single stock speaker is still there and in tact and not have to cut anything to achieve this and keep the stocks just in case as I do not want to start hacking into a unmolested car. The dash trim was cut for an aftermarket radio when I bought it so am placing in an aftermarket deck with an Ipod interface and new carpet as well only because the carpet is out and noty that it needs it, reseal the heater box, make sure all the ducts are connected, new bulbs and fuses and things of that nature. I have also dropped in an HEI unit and 8mm wires and regaped the plugs.

The question was asked about the tranny service and that was done when I had the motor out so it was less then 150 miles on it since.

other things that will be done is new tires, new top and well liner so it will all be ready for spring. In this long reply the point is I have yet to get it back on the road and I know the HEI will not solve this low end problem so I am sure that since it was an issue when I posted last that it will not magicly go away when the sun comes out. When I have it back in the air I will look at the gear ratio as I am sure the tag is still on there and if not I plan on doing the fluids anyway so I will know what gears are in there now

Any other ideas or comments are appreciated and sorry fo writing a novel....

[Olds64]

You might want to check the tension on your secondaries. 70wCars would know for sure, but I have heard that quite a few Quadrajets have problems with good power because the secondary air doors are adjusted too tight. Since quadrajets have vacuum secondaries they will only open as fast as the air can push them open. Even if you open the carburetor up all the way and the throttle plates snap open there won't be any air going through the secondaries if the air doors are closed due to an overtightened spring. There is an adjustment on the choke side of the carburetor right next to the secondary air door pivot point. Hope this might help.

[speedy_87ss]

hello, new member here, hope to help as well as gain knowledge. I have many years performance tuning, chassis dyno is my tool of choice, let me share my take on this if I may. There have been good replies, all hopefully used as I bet they were intended, a starting point in getting the performance you think the car should have.
First issue, lower compression due to non-oem pistons during a previous rebuild. Ah, not so much. You can, and I have run close to 11:1 with the stuff that passes for gas these days, but be known, because of the fuel, there was little performance gain, nor would there be a huge loss by yours lowering slightly.
Cam timing less than optimum due to el-cheapo timing set? Now your getting somewhere! Never rebuild without degreeing the cam, unknown variables are not acceptable in proper tuning.
Ignition, you mentioned installing an HEI. Excellent, and yes this helps efficiency, thus power and torque. If you don't already have a timing advance light, get one. You will need this to taylor your mechanical advance curves, there is a ton of torque to be found here! Also, don't skimp on module or hardware. I use MSD modules, low-res carbon buttons and Blaster coil. Bullet proof set-up.
Now, carburetor. For non-race purposes, you only need to know 3 words for the Qjet, secondary air valve. This is crucial. If it's adjusted too soft, it opens way to quickly,, bog city!! If it's set too tight, flat and lazy but no bog. Each combo is different, tune this for your specific package.
Lastly, you really need to know your rear gear ratio. Deeper gears can compensate for a poorly engineered engine program, but very tall gears can also make a nice package feel mighty lazy. Remember the car is a full meal deal, everthing has to work together if you want to be happy!
Hope this helps, my opinions only, your milage may vary,,lol
Jeff

[88 coupe]

Originally Posted by speedy_87ss

hello, new member here, hope to help as well as gain knowledge ........

Good post. Welcome to the site.

Norm

[speedy_87ss]

Thanks Norm, glad to be here. Looks like a very decent forum.
Jeff