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Discussion Starter #1
I don't like $600 radiators, milky oils, segmented and clamped heater hoses, or overly complicated stuff. I'm starting to get all kinds of hot for Gen1. Same cheap bottom end, but cheap iron heads and intake manifolds too. I even like the big round 14" air cleaner element. Huge surface area there. I'm only 34, and I'm really starting to think they did it all perfect by about 1968.

So I'm thinking that I want to replace anything that breaks with generic circle track Gen1 stuff from Summit, and I'm wondering why our Gen2 heater hoses have four different pieces with plastic fittings (I used an old socket for a restrictor, and coolant for all metals) and our radiators don't have caps, and our reservoir is plumbed in through the heater hoses.

GM must have had so much faith in their iron castings that they just didn't care how hot they got. Theoretically, if you didn't notice the lights or hear the "ding", you might just keep driving as bearing temps went to 300+ degrees. Sound right? No pop, and no rush of steam?

Why is that? Did they need huge pressures to eliminate hot spots in the cylinder head passages? Were they going 10/10ths by forcing heat rejection by running elevated head temps like Winston Cup? Did they have a real reason for running 230* head temps?

Why not just run a set of 5/8" heater hoses to the pump and a Gen1 style radiator with an overflow tank instead of a pressurized reservoir? Is it that reverse cooling put too much air in the system and the pressurized reservoir was needed to remove that air and prevent steam and hot spots? What if you never get above boiling point?

*I don't actually have a cooling issue, I'm just wondering.* *I do like the Gen2/LT engines quite a lot*
 

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The radiator doesn't have a cap because it's not the highest point in the system, so you wouldn't be able to use it to top off the coolant. Since they needed a higher fill point anyway, it was just cheaper to make a radiator without a cap. The cap on the expansion tank is pressure rated, and will blow off like a standard radiator cap if you get it too hot and build up too much pressure, IIRC, our cap is rated at 16 LBS. Most, if not all, modern cars have the expansion tank as a flowing part of the cooling system. It makes for a completely sealed system. With a standard overflow tank open to atmosphere, you loose water as it evaporates out of the tank. That's all fine if you keep an eye on the level and change your coolant every 50K like in the old days. With modern 150K mile coolant life, and a completely sealed system, the need for the average car owner to worry about their cooling system is basically non existent.

The reason our cars are made to run so hot is fuel mileage and emissions. Hotter heads and a hotter intake manifold vaporize the fuel better, which leads to more complete combustion. This is why there is a coolant line plumbed through the throttle body. It robs a few HP(8HP I think), but adds a bit of fuel mileage and lowers emissions. As a two ton V8 built in the 90's, they needed all the help they could get on that front.

Remember too that, for a car built in the 90's, the LT1s have their compression ratios through the roof, 10.5:1 in B and D bodies, higher in F and Y bodies. The reverse flow cooling is how they got away with it. Because it works so well, even 87 octane gas works fine in a B-body. By comparison, the Gen I counterpart 350 in the '94 Silverado only had 9.2:1 compression. With a Gen I of the same era, 10.5:1 would require premium gas at a minimum.
 

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Just out of curiosity, why would you keep the clutch fan when you could get HP by converting to dual electrics? Why mention that you have no resonators? No power gained there, just potential drone. Why would you use a Granatelli MAF given all the negative experience people have had with them and the lack of power to be gained with that mod? Search the forum for these issues and you will learn useful infrmation in addition to what Bugman has stated above. Good luck.
 

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............So I'm thinking that I want to replace anything that breaks with generic circle track Gen1 stuff from Summit, .............
Regardless of what you do on the rest, if you are looking for generic "round track" stuff, you need to shop at Speedway Motors. Usually better prices, and if you are patient, and look for the discount codes, you can find cheap/flat rate shipping .
 

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Discussion Starter #5
Thanks for the info Bugman. So the reservoir cap will pop and is rated at 16psi? That changes almost everything about my original post, and I’m betting it even says this on the cap. I can be so obtuse.

Since the reason for the reservoir being plumbed directly into the cooling system and being sealed is related to maintenance, and the system’s pressure requirements are no different than any other SBC, I can run any coolant overflow tank and 5/8” heater hose setup I feel like. It’s nice to be able to use generic pieces if the reservoir gets damaged or I just want something else. I can get 100% silicone heater hose from my local Truck Pro, and I can use any radiator that fits the front of the car, as long as I bleed the system fully after the install. I wonder about the reverse flow of the system creating air pockets, but I suppose adding something like Water Wetter might remove the surface tension on the water and perhaps help prevent air from staying trapped in the system.

GM abandoned the idea of cooling the heads first for some reason, but I think it’s a pretty trick idea. GenIII and beyond have almost has high or higher compression ratios while running alloy heads just like F and Y body with the trucks calling for 87 octane. I’ve driven a friend’s 2002 WS6 running 87 octane (he always ran it that way) and didn’t hear any pinging. The knock modules were probably pulling loads of timing.

I always thought the throttle body coolant line was there for de-icing in cold climates. I also assumed that the air moving past the throttle blades was moving fast enough at WOT to not pickup much heat from TB. My current intake temp at the elbow is around 50* when cruising on the interstate, and goes to around 100* if the car sits.

I’ll refrain from bringing up any more Gen1 love going forward.
 

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Discussion Starter #6 (Edited)
Just out of curiosity, why would you keep the clutch fan when you could get HP by converting to dual electrics? Why mention that you have no resonators? No power gained there, just potential drone. Why would you use a Granatelli MAF given all the negative experience people have had with them and the lack of power to be gained with that mod? Search the forum for these issues and you will learn useful infrmation in addition to what Bugman has stated above. Good luck.
Looks like you read my signature. I wrote that stuff so that others could ask questions if they wanted. There is a plan here.

I am keeping the clutch fan, for now, because every truck I’ve ever seen has one, right up to my former 2012 Nissan Titan. Years ago I built a stripped out, race ported, 13B RX7 and went with electric fans. It overheated shortly after. I rewired, melted relays, replaced fans, replaced all of my wiring, forgot to flip the switch, and after many other dramas, replaced everything again, that time with a huge fan from a late model 4.6L T-Bird. This car needs to tow and stay cool. The fan was the easiest and quickest way. It costs $50. I will get the car dyno’d and then you can laugh at me.

The resonator delete resulted in a tad more bass. I did it because I was bored and it was cheap and I thought it would make the car loud enough to hear… at WOT. I’m a kart racer, why would I care about a bit of drone? You have any idea how violent a Phantom Seraph gets around 70mph?

The Granatelli MAF was the only 3.5” MAF I could find on eBay for $6. I paid $12 after shipping. The whole intake track is the stock box with paper element, 3.5” coupler, MAF, 3.5” hump coupler, 3.5”x12” pipe, stock elbow with hockey puck. The whole thing cost less than $70 and is completely straight. I’ve had no problems with the setup, and the cars pulls better on the top end. It fits the plan.
Here is the rest of my plan. Mods will go in this order:

2-1/4” offset/offset straight through mufflers – 400+cfm each

2-1/4” 300 cell converters – 400cfm each – spaced 30” from the end of the manifolds or header primaries.

What I can use of the stock pipes @ ~350cfm each? No idea about the water or Hg on any of these flow numbers.

Summit TB airfoil. I’ve never seen a twin blade TB on an HO engine without one. Check out the new Ford stuff.

3.42:1 Motive final gears, reluctor ring, 30 spline 8.5” True Trac LSD, Summit rear girdle.

Sonnax performance shift kit setup for “medium” firmness. There may be servo replacement involved. That’s a question for Sonnax.

12” 2400 stall converter – GM18AH reman. I have to tow a trailer full or karts or I would have bought an F body.

Valve springs, timing chain, and 216/226ish 490/520 lift at the valve cam degreed for bottom end. ZZ3, ZZ9, hot cam, 845, 227, whatever I find for the least money. I’ll use 1.5/1.6 rocker arms and tall valve covers if needed.

30lb injectors/big boy pump

Rear control arms, pinion angle, 15x10s, 295/50/15s, driveshaft loop, built trans with hard parts, carb’d 572, 32x17x15s, tubs, Ford 9, adjustable shocks, cage, 500hp NOx shot.

Duramax.

Do my posts make sense now?

Now back to Gen2 cooling.
 

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Discussion Starter #7
Regardless of what you do on the rest, if you are looking for generic "round track" stuff, you need to shop at Speedway Motors. Usually better prices, and if you are patient, and look for the discount codes, you can find cheap/flat rate shipping .
Thanks man! I had forgotten about those guys.
 

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GM abandoned the idea of cooling the heads first for some reason, but I think it’s a pretty trick idea. GenIII and beyond have almost has high or higher compression ratios while running alloy heads just like F and Y body with the trucks calling for 87 octane. I’ve driven a friend’s 2002 WS6 running 87 octane (he always ran it that way) and didn’t hear any pinging. The knock modules were probably pulling loads of timing.
GM abandoned the reverse flow cooling because they didn't invent it, then got sued by the guy who did and lost(at least that's my understanding of the situation). The reason newer cars can run more compression is almost entirely related to combustion chamber shape and camshaft profiles. The LSx style head is leaps and bounds more advanced than the Gen I and II heads. While the Gen II is a minor evolution of the Gen I, the Gen III is a major advancement. A more advanced chamber shape, along with more advanced cam profiles allows more compression without knock and, incidentally, a relatively large jump in HP(50HP in the Gen III over the II) without losing any fuel mileage and maintaining tailpipe emissions.

If you eliminate the stock coolant reservoir, you will still need someplace for the steam pipe to vent. On the stock LT1, this it the pipe that goes from the back of the heads, through the throttle body, and into the coolant reservoir. Without it, you will get steam pockets in the heads, even with water wetter.
 

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Discussion Starter #9 (Edited)
GM abandoned the reverse flow cooling because they didn't invent it, then got sued by the guy who did and lost(at least that's my understanding of the situation). The reason newer cars can run more compression is almost entirely related to combustion chamber shape and camshaft profiles. The LSx style head is leaps and bounds more advanced than the Gen I and II heads. While the Gen II is a minor evolution of the Gen I, the Gen III is a major advancement. A more advanced chamber shape, along with more advanced cam profiles allows more compression without knock and, incidentally, a relatively large jump in HP(50HP in the Gen III over the II) without losing any fuel mileage and maintaining tailpipe emissions.

If you eliminate the stock coolant reservoir, you will still need someplace for the steam pipe to vent. On the stock LT1, this it the pipe that goes from the back of the heads, through the throttle body, and into the coolant reservoir. Without it, you will get steam pockets in the heads, even with water wetter.
Understood about the reservoir, I'd have to come up with a suitable replacement.

I've read about the GenIII heads and their ports and chambers. 15* valve angles and injectors pointed directly at the back side of the valve face to minimize fuel drop out. I read an article about development here:

http://netmotive.net/articles/hib/ls1c.html

The cooling system is also discussed, and the reasoning for the change is listed as being due to reverse flow and air in the system.

I have NEVER heard or read about the lawsuit. Where did you get that info? I want to know more about this.
 

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I have NEVER heard or read about the lawsuit. Where did you get that info? I want to know more about this.
Evans Cooling Systems V. General Motors

http://www.leagle.com/decision/19971573125F3d1448_11378.xml/EVANS COOLING SYSTEMS v. GENERAL MOTORS CORP.
http://www.businessweek.com/news/2006-03-20/gm-must-face-retrial-on-claim-of-trade-secrets-theft-update3
http://www.nytimes.com/2004/01/11/nyregion/his-trade-secret-or-a-company-s-property.html?src=pm&pagewanted=1

Cliffnotes: Evans came up with a reverse flow cooling system, and claimed GM stole the design from him. GM claimed they invented it first, and produced a document showing that they did, but it was later proved a forgery. Initially, a judge sided with GM saying that Evans gave away his rights to the design when he demonstrated the system to GM engineers. Then it went back and forth as it move to higher and higher courts.
 

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Discussion Starter #11
Do you think the "pin hole vent" made it to production? My understanding of the reasons for the Gen1s demise was tooling. It was worn out and it became less expensive to redisign. I've also heard or read that Gen 1 would not be able to meet CAFE or future emissions standards. The lawsuit must have been a side thing that didn't really influence Gen3 development because development would have begun before the lawsuit was filled in '94. This is fascinating, and those links are great!
 

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Do you think the "pin hole vent" made it to production? My understanding of the reasons for the Gen1s demise was tooling. It was worn out and it became less expensive to redisign. I've also heard or read that Gen 1 would not be able to meet CAFE or future emissions standards. The lawsuit must have been a side thing that didn't really influence Gen3 development because development would have begun before the lawsuit was filled in '94. This is fascinating, and those links are great!
yes, future emission requirements was a big part of the engine updates.
GM was trying to get to the point where the engine would start in less than one crankshaft revolution and reduce unburned hydrocarbons, the optispark was their first step then the later gens achieved it.
 

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Discussion Starter #13

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That explains why my '98 C/K truck starts as soon as I touch the key. The Impala starts almost,but not quite as quick...
 

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Discussion Starter #15
I didn't say it was the fastest ever, just the fastest I've owned. The Mazda RX7 was the slowest, with 120lbs of cranking pressure. We gotta move this discussion. I have zero issues with an oldschool HEI distributor and block first cooling. I'm growing this obsession with building a cheap cast 400 with a near zero deck height, 4.125 bore, 3.75 stroke, and whateve length rod it takes to connect it to a normal sized cheap hyperutectic piston. I'm loving a tight chamber with some nice tight quench area. All iron, TBC coated crowns, chamber, valve faces, and exhaust ports. I'll probably never be able to build a SBC like this, but I will build a kart motor with full coatings. I want to run as little timing as possible, and I want to do it all with cast iron, big chambers, lighting fast flame fronts.
 

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Discussion Starter #16
That explains why my '98 C/K truck starts as soon as I touch the key. The Impala starts almost,but not quite as quick...
What's your cranking compression pressure on the Impala? Lots of cam overlap?
 

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Have no idea regarding cylinder pressures,stock cam/heads...
 
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