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  #31 (permalink)  
Old 12-08-2007, 10:25 AM
Rambler American -69
 
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I have been too busy to do anything for the car lately. I went to garage today and decided to spend some time with the project when I can.

About the torque converter. The most common speed limits here are 80km/h and 100km/h. Tachometer shows 2400rpm@80km/h and 3000rpm@100km/h (I checked the speed from GPS-device). Should the stall speed be lower than 2400 to prevent overheating of the tranny oil? I found these two converters from summit:

HUP-GM25
HUP-GM25HD

Is this "heavy duty" necessary?

Advertised stall is 2500rpm. The stall speed is dependent on the torque so I don't know what the actual stall will be. Is this converter good?

Here's the Summit Racing parts for the tranny (thanks FBird'88):
Rebuild kit HUP-HP3288K
Drain plug BMM-80250
Shift Kit TRG-350
Torque converter: HUP-GM24(HD)? or something else?

I try to keep my budget reasonable, so don't suggest way too expensive parts

By the way, my new old tranny has 9" tail and the old one has 6", is it just bolt-on swap? I have to change the internals anyway, so I think I will by some good repair/rebuild manual for TH350 also.

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  #32 (permalink)  
Old 12-08-2007, 10:33 AM
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It the past summer I have seen 2 of the Eagle 383 cast stroker cranks break at the front rod jounrnal radius. I have heard that this is not uncommon for this crankshaft. Also, the Eagle SIR I-Beam rods are too unstable to keep the big end round.

Edited to add that I see you are using Scat I-Beam rods. Good choice.

tom
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  #33 (permalink)  
Old 12-09-2007, 11:59 AM
Rambler American -69
 
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I ordered these:
Rebuild kit HUP-HP3288K
Drain plug BMM-80250
Shift Kit TRG-350

I keep on studying torque converters from internet and buy it later. It is still winter here and about 6 months until I drive the car out from garage.
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  #34 (permalink)  
Old 02-03-2008, 12:55 AM
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Now that the tachometer works again, I have found a problem with my setup. When I rev the engine at standstill WOT, the engine started to bog at 4000rpm. I bought vacuum secondary spring set. I tested every one of those springs and even with the tightest spring, the engine bogs around 5500rpm. If I push the gas pedal a little less, the engine revs nicely up to the rev limiter 6000rpm. It's still winter here so I can't test drive the car. What will be the situation when accelerating the car? More load, more vacuum, earlier bog?

Is my air filter limiting too much air flow? Too much vacuum? Perhaps I should install a vacuum cauge. I have now only the "RAM horn" exhaust manifolds installed because I have to modify the shorty headers due to clearance issues.

Any ideas what's the problem?
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  #35 (permalink)  
Old 02-03-2008, 03:52 AM
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how much clearance between the air cleaner top and the carb choke horn?
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Old 02-03-2008, 04:07 AM
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Carb is Holley 750cfm 3310-2. Choke system has been removed by the previous owner. Choke horn is still there. Here's a pic of the air cleaner. Regular 14" filter.



I measured the distance from choke horn to top of air cleaner, its 20mm (0.787inches).
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  #37 (permalink)  
Old 02-03-2008, 04:23 AM
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Carb is Holley 750cfm 3310-2. Choke system has been removed by the previous owner. Choke horn is still there. Here's a pic of the air cleaner. Regular 14" filter.



I measured the distance from choke horn to top of air cleaner, its 20mm (0.787inches).
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Old 02-03-2008, 04:23 AM
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For good quality and not too expensive torque converters, try PTC PTC home page
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  #39 (permalink)  
Old 02-03-2008, 04:26 AM
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I'll guess your problem with not being able to rev might be timing. You should have about 34-36 at about 3000rpm.
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  #40 (permalink)  
Old 03-24-2008, 07:15 AM
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I found a vacuum leak from a broken hose to the intake. It's fixed now. However , it's still winter here and I took the engine out.

I'm installing those new internals to the tranny. I bought 2500rpm stall converter (HUP-GM25HD ) and aluminum radiator SUM-380328 .

I looked Summit catalog and found main cap studs. Should I buy those and install them? Right now I have main cap bolts. How much hp can bolts take? How about studs?

My future plans will be to upgrade e.g. AFR heads and let the engine rev up to 6500rpm, so it would be an easy job to change the main cap bolts into studs now that the engine is attached to engine stand.

By the way, this is great forum to find tons of information for a newbie like me
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  #41 (permalink)  
Old 03-25-2008, 12:35 AM
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You have to realise that when these 14" drop base air cleaners were designed, the OEM holley carbs had a shorter choke horn and dog leg/down leg venturii boosters that sat lower in the venturii. Your aftermarket 3310 holley has a standard straight booster style and a tall(er) choke horn height to allow the choke flap to clear the boosters.
For best performance you want to cut down or cut off the choke horn, like on a Holley HP carb.
A must do on a BBC with this carb and aircleaner. You should do it too.
Edelbrocks and Qjets have a lower choke horn and are not so much of an issue.

You can also shorten the bowl vent tubes a bit with a slash 30° angle cut.
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  #42 (permalink)  
Old 03-25-2008, 01:12 AM
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When it comes to torque converters on the street, its always a trade off.
You'll have to decide how much stall (and ultimate launch power) is right for you.
When you are cruising along at part throttle at say 80KLPH or 100KPLMS with say a 10" "3500 stall" converter, there is not much load on the converter.
There is good airflow to cool the trans and converter. (tranny oil cooler)
There is slightly more converter slip, than stock converter and a bit more heat. A good add-on towing tranny cooler that gets good air flow will take the heat away.
But when going up a long steep hill, or pulling something (high(er) power load) then you can build some heat in the trans.

If all you do is cruise around, and pound on it a good bit, but do not tow or have to go up long hills, the high stall converter will not cause problems. With the camshaft you have, you can easily use up to a 3600 stall converter for maximum performance (with sticky tires).
For maximum performance, You ideally want the max converter stall speed to be about 500 rpm under the peak engine torque rpm point at launch. You will easily over power normal street radial tires with this 3600 stall converter. But if you have sticky tires and want maximum launch, you want this converter.
Like you said, converter maximum stall is relative to input torque. So you can easily control/ regulate the launch by feathering the throttle a bit on launch with a high 3600 stall to match the available traction at the moment.
When you have the slicks or DOT stickies on, give 'er all it has.

I would have gotten a converter with more than 2400 stall to make it worth while. A good compromise would be a 2800-3200 actual stall. 11" high stall converter or tight design low stall 10" converter. In my opinion a "2400 stall" is just a cheap tweeked, restalled stock 12" GM converter and not enough especially if you like a hard launch and ever plan on using a sticky tire, say for drag racing. A stock GM 12" th-350 converter will give you 2100 stall behind a 350ci motor. Keep in mind when they tweek/ "restall" a stock GM 12" converter to raise the stall speed, they just tweek the turbine blade angle making the converter less effecient. to get the higher 2400 stall speed. This increases the heat produced. there is a limited amount you can tweek a stock converter and you will give up effientcy.

A real performance built high stall converter, based on a smaller than stock converter case is like night and day. You get what you pay for.
This is one area where it pays to burp the wallet at bit. Especialy if you plan on more power in the furture.
The right converter makes a huge, huge difference. Summit Racing has a very, very limited selection of converters.

http://www.atiperformanceproducts.com/
http://www.redneck-performance.com/
http://www.gopnh.com/index.cfm

You'll have to decide the right balance for your car.

Last edited by F-BIRD'88; 03-25-2008 at 01:27 AM.
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  #43 (permalink)  
Old 03-25-2008, 12:40 PM
Rambler American -69
 
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Thanks for the answers. I was in a too hurry to buy the converter with 2500rpm stall. Luckily it was not that expensive part. Perhaps I will test it next summer and sell it if I'm not satisfied.
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  #44 (permalink)  
Old 03-25-2008, 04:50 PM
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Quote:
Originally Posted by jankinnu
I looked Summit catalog and found main cap studs. Should I buy those and install them? Right now I have main cap bolts. How much hp can bolts take? How about studs?

By the way, this is great forum to find tons of information for a newbie like me




ask machine shop tom, but I think leave it alone. studs change the torque clamping pressure over the bolts.

ask around B4 you change.

sounds like your doing real good with yer ported 76cc heads ect. I would like to see some dyno #s. as had a set of 76cc heads with 2" stainless intakes and 1 1/2 stock exhaust valves. The intake ports are gasket matched and the chambers have been polished. They have comp springs and retainers. The heads were clean and fresh as the valve job had only about 3000 miles on it. everyone said use a different head. so I ended up selling these 76cc heads and buying a fresh set of #187 64cc camel humps with acc holes and a set of vortec 062 heads. the camel humps are on a 400SBC we will see how they do next weekend.
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  #45 (permalink)  
Old 05-20-2008, 12:12 AM
Rambler American -69
 
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My entire project (14 pages) can be found here:
http://www.amccf.com/yabb2/YaBB.pl?num=1166690633

New modified headers sound nice I'll check the timing this week. If the timing is right and it still bogs around 4000-5000rpm, should I replace the power valve? What size main jets you would recommend for this kind of setup?

About the timing. When I remove the vacuum hose from the distributor during the timing measurement, should I plug the vacuum holes from distributor and carb?
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