The Oldsmobile Connection

c_creations · Posted: Tue Oct 18, 2005 10:55 pm Post subject: Rev.

Is there a built in rev limiter in the stock delco distributors. i would like to get it to spin to around 6500-6800 but i dont want to get a new distributor. what should be done?

88 Coupe · Posted: Wed Oct 19, 2005 12:36 am Post subject: Re: Rev.

Hi c_creations, hello everyone,

Quote: Is there a built in rev limiter in the stock delco distributors. i would like to get it to spin to around 6500-6800 .........
Unless there is one in your tach, you do not have a rev limiter. The limit is in your engine.

Your engine is not capable of 6500 RPM, and your shift point is probably well under 5500 RPM. A stock 350 is closer to 4500.

A dyno or timeslips are the only practical ways of finding your shift points.

Did I ever mention that racing can get expensive quick? It's the main reason I don't race.

Regards, Norm

c_creations · Posted: Wed Oct 19, 2005 1:07 pm Post subject:

maybe my engine is not so stock, with my crank as long as i stay under 7000 i should be fine. Yes i know its expensive. But its what i do.

andrewk · Joined: 18 May 2005 Posts: 1233 Location: Ames, IA

c_creations wrote: maybe my engine is not so stock, with my crank as long as i stay under 7000 i should be fine. Yes i know its expensive. But its what i do.

I dont really understand what you are saying, but I would worry about your valve train before I would worry about a crank. If you have stock springs, your engine is not capable winding up like that, the valves will float. How many RPMs you can run depends on a number of factors, like rotating assembly weight and balance, valve train, cam, and everything else. If your heads dont flow well enough at high RPM, then the engine wont run at high RPM. If you overrev the thing too much you can have a rod come apart or you can break a piston. The crank usually isnt the cause of failure, it is usually a by-product. You wont be doing much "racing" unless you know EXACTLY what you have and know the limit of those components.

Andrew

c_creations · Posted: Wed Oct 19, 2005 4:13 pm Post subject:

it has #5 heads, so that wouldnt be a problem, and it has been rebuilt for drag racing, springs might be an issue, but floating would be the least of my worries

andrewk · Joined: 18 May 2005 Posts: 1233 Location: Ames, IA

c_creations wrote: it has #5 heads, so that wouldnt be a problem, and it has been rebuilt for drag racing, springs might be an issue, but floating would be the least of my worries

Why the least?? If your valves float at 5800, or 6000, then your engine ceases to make power. When valves float, RPM increase ceases. So you have #5 heads, has there been any work done to them? What are the valve sizes? What is the rocker ratio? Do you have any aftermarket vavle train parts? What about your rotating assembly? Was it balanced? Was it blueprinted? How heavy are the pistons? How heavy are the rods? What is the rod journal size? What about the oiling system? Any modifications? Compression ratio? Intake? Cam? Carb? What Ignition? "rebuilt for drag racing" doesnt mean anyhting to me with out specifics. I could rebuild a 8 horse Briggs and Stratton engine for drag racing, but that doesnt mean it is any good. Im not saying your engine isnt good, but you need to know what you have before you go flogging it down the track. Im not sure that you know what you should be worried about. I would suggest you find out exactly what you have so know what you can do with it to avoid having problems. If that means it is a 14 second car that runs 5800, then thats what it is. When you force things, you break things. Simply put, again, without knowing the capabilities of what you have, running the engine that fast is asking for a few "inspection holes" in the oil pan. This post looks alot like my previous one, do you think there is a reason?? Ya gotta know what you got in order to know what you can do!!!!!

c_creations · Posted: Wed Oct 19, 2005 10:14 pm Post subject:

Hmm. IM gunna call the guy tomorrow. cause it was rebuilt, and then bought, it was rebuilt by a guy that builds these motors, but i have no clue what is in it. This sucks. I ahve no clue what it has. so yea, can you see a problem here. but im not wanting to break it down just to find out.

88 Coupe · Posted: Wed Oct 19, 2005 10:56 pm Post subject:

Hi c_creations, andrewk, all,

I've been reading your threads since before this one. I just went back and reread it. It clearly shows me you haven't learned anything, except how to put on a "ricer" attitude.

I spent over an hour composing and editing my above reply so it could not possibly be misunderstood. Obviously it was a waste of my time.

Quote: maybe my engine is not so stock, with my crank as long as i stay under 7000 i should be fine .........
The only way I can possibly know this is a response to my post is that mine is the only one above it.

I made three references: The engine you think you have, the one I'm guessing you have, and a stock 350. You responded as if I said yours was stock, then you contradicted me as if you know what you're doing, and I know nothing .......... Not the best way to get help from me.

In one of your other threads on this very same subject, I suggested you do three things to begin learning what you actually have, and how to work with it .......... No one can help you, unless you read and understand the advice given, and ask questions about any part you do not understand.

In another (maybe the same one) and also the above link, you said you have a small budget and you have no one to help you ......... Any idea why I find alternatives to using aftermarket parts?

When you decide to get off the "ricer attitude" and ask about the information you are given, you will get some help you can use.

I don't believe I need to say it when dealing with an adult, but here it is anyway:
This post is intended as advice, not flame. If you think you see any flame, go back and reread it.

Regards, Norm

88 Coupe · Posted: Thu Oct 20, 2005 12:13 am Post subject:

Hi andrewk, all,

Did I say anything about valve float, or breaking parts?

Quote: .......... If your valves float at 5800, or 6000, then your engine ceases to make power ..........
Valve float is not related to peak HP, shift point, or max RPM unless it occurs at less RPM than that event.

After the power peaks, it drops off rapidly. The engine will still rev more but at a much slower rate. Next there is a point where it will not rev any more. This is what most people, mistakenly, call valve float.

He hasn't mentioned it sounding like it exploded, so he has not floated his valves.

Theoretical shift point, is just past the point of peak HP. In his case it's well under 5500. This is an educated guess, but it's all we have until he gets a dyno sheet or timeslips to tell for sure. For comparison, I used a peak of 4500 or so for a stock 350.

He wants to turn more RPM, even when it's not making power any more? Good example of why "ass dynos" do not work.

Why would anyone want to stay in first gear, if more power (acceleration) can be had by shifting to second?

Quote: ......... I could rebuild a 8 horse Briggs and Stratton engine for drag racing .........
http://www.briggsracing.com/display/router.asp?Docid=101391

Quote: .......... This post looks alot like my previous one, do you think there is a reason?? Ya gotta know what you got in order to know what you can do!!!!!
Looks like several of my posts.

Regards, Norm

88 Coupe · Posted: Thu Oct 20, 2005 12:40 am Post subject:

Hi c_creations, all,

Quote: it has #5 heads, so that wouldnt be a problem ........
Please explain how that fact might be related to the discussion.

Quote: ......... it has been rebuilt for drag racing .........
That's what you were told. I doubt if it's a true statement. I question the qualifications of the person that made it. I base my opinion on the fact that the carb (as used in that supposed application) is a street carb. The Q jet on your 307 would have been a better choice.

Quote: ......... springs might be an issue ..........
They should not be. Part of a head rebuild is a check of the springs and replacement as necessary. In the case of a cam upgrade, new matching springs would be installed.

Quote: ......... but floating would be the least of my worries
You are probably right.

Regards, Norm

88 Coupe · Posted: Thu Oct 20, 2005 1:26 am Post subject:

Hi c_creations, all,

Quote: .......... it was rebuilt by a guy that builds these motors .........
Big difference between built and rebuilt. Incorrect terminology leads to miscommunication and misinformation.

Quote: .......... but i have no clue what is in it ........
The first step in solving a problem is to define it. You've just taken your first baby step.

Quote: .......... im not wanting to break it down just to find out.
It's much easier to have him give you the specs, but, as I've told you several times, there are other ways to find what you need.

Regards, Norm

andrewk · Joined: 18 May 2005 Posts: 1233 Location: Ames, IA

88 Coupe wrote: Hi andrewk, all,

Did I say anything about valve float, or breaking parts?

Quote: .......... If your valves float at 5800, or 6000, then your engine ceases to make power ..........
Valve float is not related to peak HP, shift point, or max RPM unless it occurs at less RPM than that event.

After the power peaks, it drops off rapidly. The engine will still rev more but at a much slower rate. Next there is a point where it will not rev any more. This is what most people, mistakenly, call valve float.

He hasn't mentioned it sounding like it exploded, so he has not floated his valves.

Theoretical shift point, is just past the point of peak HP. In his case it's well under 5500. This is an educated guess, but it's all we have until he gets a dyno sheet or timeslips to tell for sure. For comparison, I used a peak of 4500 or so for a stock 350.

He wants to turn more RPM, even when it's not making power any more? Good example of why "ass dynos" do not work.

Why would anyone want to stay in first gear, if more power (acceleration) can be had by shifting to second?

Norm,
You did not mention anything about that, it was my reply to him just wanting to turn more revs. I see that I have been misinfomed about valve float... I guess you learn something everyday. My point was that just reving the thing to 6800 is dumb, and it probably wont go there to begin with, along eith the fact that he doesn't know what he has, so therefore he can't make a sound judgement of what RPM to even take the thing to.

That said, if valve float occurs before peak RRM, I am assuming you will have all kinds of bent pushrods and such?

The Briggs racing stuff is really bad ass. We had a 5 horse "raptor" that was on a mini snowmobile come into our shop last winter.... I bet with a little kid on it it would give alot of 340s a run for their money....:shock: :shock:

Quote: Hi c_creations, andrewk, all,

I've been reading your threads since before this one. I just went back and reread it. It clearly shows me you haven't learned anything, except how to put on a "ricer" attitude.

I spent over an hour composing and editing my above reply so it could not possibly be misunderstood. Obviously it was a waste of my time.

Quote:
maybe my engine is not so stock, with my crank as long as i stay under 7000 i should be fine .........

The only way I can possibly know this is a response to my post is that mine is the only one above it.

I made three references: The engine you think you have, the one I'm guessing you have, and a stock 350. You responded as if I said yours was stock, then you contradicted me as if you know what you're doing, and I know nothing .......... Not the best way to get help from me.

In one of your other threads on this very same subject, I suggested you do three things to begin learning what you actually have, and how to work with it .......... No one can help you, unless you read and understand the advice given, and ask questions about any part you do not understand.

In another (maybe the same one) and also the above link, you said you have a small budget and you have no one to help you ......... Any idea why I find alternatives to using aftermarket parts?

When you decide to get off the "ricer attitude" and ask about the information you are given, you will get some help you can use.

I don't believe I need to say it when dealing with an adult, but here it is anyway:
This post is intended as advice, not flame. If you think you see any flame, go back and reread it.

Regards, Norm

I agree 100 percent Norm.

Andrew

88 Coupe · Posted: Fri Oct 21, 2005 5:06 am Post subject:

Hi andrewk, all,

Quote: ........ it was my reply to him just wanting to turn more revs .........
I know. That comment was to all. I should have been more clear. :blush:

Quote: ........ it probably won't go there to begin with ........
Assuming a 215* cam, his might go to 6000, or more, but it would be way past it's power band. If the heads were properly rebuilt, valve float could not be an issue.

If one shifts 500 RPM under his optimum shift point, he will see little difference in his ET. Shift it 500 over and there will be a big drop, although his "ass dyno" will tell him it went quicker. I choose to believe the timeslip.

Quote: I am assuming you will have all kinds of bent pushrods and such?
Although it doesn't always cause damage, it definitely lets you know it happened.

If there is damage, the bad news is: The bent pushrods would be the result of contact with pistons. Pieces of those pistons might be found all over the engine and exhaust system.

Good news is: It only happens in the cylinders where any valves actually float.

Regards, Norm