RE: Compression Ratio Question?
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RE: Compression Ratio Question? - 2/25/2007 9:20:02 PM
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2000BlazerSS
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Jackle: I understand that kids today don't know, let's say, as much as us older folks. But then most of us older folks don't know SQUAT about fuel injection and have to learn everything new. Not fun.
Go to the link ceanern provided, just click it on, then read it. There's 2 pages and you have to print one and then the other, do that. Then read what they say about the cylinder heads they used, and all the choices they had to chose from.
Ask yourself a question, why didn't they start with a 1996 or later Vortec head if that's what they used on a later 4.3?. I know it's a GREAT head, I've been reading tests on it for YEARS. Why did they use a pre-Vortec head to modify?.
But I digress, if your going to do all those modifications you should at least learn about how the pro's build an engine like that. Don't just go by what your "experts" say, but go to the site, read about it yourself. And the heads that they used, and the choices they had to choose from.
I'm 90% sure that when I look at the combustion chambers of a late model 4.3 they won't look like my V8's.
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RE: Compression Ratio Question? - 2/25/2007 9:48:11 PM
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2000BlazerSS
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Thanks, that answers a whole BUNCH of questions, especially and particularly the heads, that head chamber used in 1996 is the same heart shape as the V8 Vortec. It means that the 1996 and later head is a pretty damn good head as is. The valves are 1.94 and 1.50 plenty for a 350V8. They add 40hp to most V8's just bolting them on. This is a big thing to me. But I question why the people building the "hot rod" engine in HRM used an earlier head and modified that instead of the better Vortec head. They didn't I would've but that's what makes the world go round.
I'll hit print anad print it out when I get done with some ZL-1 sheets I copied, I was asked to "prove" the 3rd Corvette ZL-1, but I feel it's another bogus one.
Thanks for passing this along, you can't have too much information. Like I said, I was there from day one on the 90 degree V6, I never paid much attention because I never thought I'd ever have a need to build or play with one. Unless I stumble across a LOW mileage engine complete I never will, too much trouble for not enough reward.
PS: I would suggest you guys take the time to print out what Swartz provided, it's a terrific reference piece and handy to have. Thanks again
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RE: Compression Ratio Question? - 2/25/2007 10:09:29 PM
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swartlkk
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On thing about that HRM article is that it seems like it was written in the '95 time frame where the newer vortec heads may not have been really known about. They make some mention of them as the true vortec heads were the only ones that came with the vertical intake bolt alignment.
Also worth noting is that I have heard it mentioned in quite a few places that the newer vortec heads do not have the material around the runners for a major port job. They really don't need much but a good smoothing cleanup, however, they also may not have the material to punch out the intake and exhaust like what was done in the HRM article either.
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RE: Compression Ratio Question? - 2/25/2007 10:42:31 PM
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2000BlazerSS
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From what you say you could very possibly be right, either this was before the Vortecs came out or just as they did. I have the issue but would have to go thru a whole lot just to find it. I'm certain that if the Vortecs had been available, and they knew how good they really were, that's the head they would have used, the ports and chambers are most probably the same as the V8 head.
The true Vortecs wouldn't need major port work to be suitable for all but an engine with major modifications, they used mildly reworked ones on engines making over 400hp. What you say should be noted in any case. Also, the late intake and exhaust valves had "back cuts", that is a second angle which is considered prefered and adds to the flow at all RPM's. When they started I don't know, but trust me they did. You wouldn't be able to tell unless you took them out.
Also, and IMPORTANT is the "net lash" rocker studs and when they were used. They can be replaced with screw in studs and then you can use regular rocker arms with guides and adjust the lash as needed, if you change the cam or rockers I'd suggest putting them in (read the article).
But read this, print it out and keep it in a folder, it's chocked full of interesting and needed information if your going to pull one of these apart. I never realized what a pain in the ass it would be, all the nickle and dime changes they made.
Side note: They mention a "whine" when the balance shaft was first put in the engine. You CANNOT believe what a "situation" this created!. When the first engines hit the Baltimore plant they started sending almost every one back!. Trust me, Baltimore SCREAMED to the Corporation that Tonawanda was building JUNK!. **** hit the fan BIG time!. As it turned out, as this article states, the first gears were cut at an angle that caused a gear whine. This was at first blamed on our workers, but all WE did was put the parts THEY gave us in the way THEY told us too!. Turns out the engineers had the supplier cut the gears at a bad angle, wasn't the worker, wasn't the supplier, was the engineers. After thousands of engines were sent back and torn down for "excessive noise".
Anyway, print this article out, it's worth having a copy. Thanks again Swartz.
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RE: Compression Ratio Question? - 2/26/2007 7:00:41 PM
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drperry
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And I don't think GM made a 302... A 305, yes, but not a 302... Unless it was a very limited production run...
As for noise... The 4.3 is a very loud V6, possibly because of the still mechanical driven fan...
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RE: Compression Ratio Question? - 2/26/2007 9:36:22 PM
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Jackal
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Chevy did in fact make a 302, in limited supply. I thought i had a set of 350 pistons and i took them to the machin shop, and found out they are almost a 1/2 to tall , and the guy said there for a 302...puzzled i looked at him like " and im paying you to do work on my engines"! I said you mean a 305? He said no a 305 has a different bore, but the same stroke as a 350, the 302 has the 4 in bore found in the 350 but not the stroke. I've been around cars my entire life and i just found this one out to my dismey.
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RE: Compression Ratio Question? - 2/26/2007 9:40:45 PM
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Jackal
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Also i honestly did alot of fast reading, so i may have missied something....but That hot rod articicle may have used that head setup because i am almost certain that you can't run the vortec heads and a carb intake manifold. You can but it has to be modded slightly. And it might just be because there are still alot of people out around here even that pull fuel injection and throw a 350 carburated in all the time.
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97 Blazer LS 311k RIP Rebuild to Come soon.
High CR/Will Be Turbo
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"The Hulk" http://www.cardomain.com/ride/2568605
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RE: Compression Ratio Question? - 2/27/2007 12:14:53 AM
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2000BlazerSS
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Dumb as a post and he picked THAT out!. Yes, if you had the Vortec heads they had a different intake bolt angle both the V8 and V6. I don't think they made a CARB intake for the newer heads. You probably could use one on Vortecs if you played with the mounting holes. Maybe. Good catch dumbie.
I only say that because you have to be brain dead not to know that back in 1967,68 and 69 they made a "few" 302 Z-28's. But then kids today..........................................
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RE: Compression Ratio Question? - 2/27/2007 3:56:33 PM
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drperry
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quote:
ORIGINAL: 2000BlazerSS
I only say that because you have to be brain dead not to know that back in 1967,68 and 69 they made a "few" 302 Z-28's. But then kids today..........................................
So I'm brain dead for not researching a car I've never seen in my life, and never will... Got'cha! lol.
I think if I was going to do any major mods like that, I'd try and get an aluminum plenum or battleship... Aren't ours made of plastic?
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RE: Compression Ratio Question? - 2/28/2007 12:48:20 AM
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2000BlazerSS
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If your near 40 and never heard of a 1967, 68, or 69 Z-28 Camaro your, uh, can't say it, but you are. And Chevy never made a 302 after or before the 67-69. Your thinking of the OTHER 302, built from 1968 to 1993. Hey J_rkle, YOUR the one bragging how smart you are, how many engines you've built, how much you know.
PS: double check those pistons, measure the diameter, are they 4 inches?, or 3 and 7/8ths?. An eighth inch smaller.
drperry: if you've never seen a 1967,68 or 69 Z-28 Camaro you'll have to keep your eyes closed for the rest of your life when you read Chevy magazines. They made 600 Z-28's in 1967, 1st year, 8000 in 68 and 23,000 in 1969 (don't hold me to those being EXACT, but those numbers are close enough).
swartz: mr knowitall never heard of a 67-69 Z-28?. drperry never saw one and never will?. Chevy built OTHER 302's?. And you wonder why I call him names?. OK. I won't
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RE: Compression Ratio Question? - 2/28/2007 6:12:37 AM
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drperry
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quote:
ORIGINAL: 2000BlazerSS
drperry: if you've never seen a 1967,68 or 69 Z-28 Camaro you'll have to keep your eyes closed for the rest of your life when you read Chevy magazines. They made 600 Z-28's in 1967, 1st year, 8000 in 68 and 23,000 in 1969 (don't hold me to those being EXACT, but those numbers are close enough).
By seen, I don't particularly mean "oooo look, there's one!" I meant more of actually getting my hands on one, driving one, or planning on owning one. Am I going to go nuts and research a car I'll only ever see in a magazine or driving down the street? NO. There's no practical point to it. Same reason I didn't come to this board until I got a Blazer, lol. I don't religously browse car magazine racks, and I live in oil patch country, I've been in this city for 10 years, and I've seen ONE Camaro that's older than 1980.
And I know quite a few people who couldn't tell a 68 Camaro from a 68 Mustang... Why? Because their tastes don't cover muscle cars. But of course, that must mean they're total and utter.... non-intelligent people, by your standards, as it sounds.
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RE: Compression Ratio Question? - 2/28/2007 8:03:40 AM
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swartlkk
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Fact of the matter is that berating other members (ie. calling names) is against our forum rules and I shouldn't have to remind everyone of these rules, but here it is. I have taken the liberty to highlight a few key words/phrases:
quote:
2. While debating and discussion is fine, respect your fellow enthusiasts. Being of a diverse background, members are likely to express different opinions, and while opinions may differ from yours, they are just that, opinions; and everyone is entitled to express theirs freely. We will not tolerate rudeness, insulting posts, or personal attacks. Do not flame, bother, bug, disrespect, hound or taunt ANYONE on the forums or through private messaging or chat room. If we feel a thread is getting out of hand we will close or delete it. You can/will lose your posting privileges if you continue this type of behavior.
So please respect one another.
Someone may know a lot more on a particular topic, but if that person comes across as a pompous, self-proclaimed know-it-all (even if said person is very knowledgable), that person will not be as respected for their knowledge as they would be if their delivery were different.
Anyway, we have gone way off topic. Please discuss the topic at hand if further discussion is necessary. Thank you.
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04 Rainier
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Please Do Not PM for Tech Help
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