1975 Monte Carlo

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Post by LSANTI76 on Sun May 11, 2014 11:13 am

At least you were fortunate to have found your braking problems in your driveway vs away from home or in heavy higher speed traffic. Brake work is one of my least favorite things to do as well. Your Monte came out very nice & I noticed you're the same 454 HO crate motor I'm running. With a 780 Holley, 2000 rpm stall, TH350 & 3.42 gears I set my initial timing @ 4 degrees BTDC & noticed I had more torque & broader power band vs an initial 8 - 12 degrees BTDC. It felt like it was running out of steam before reaching max RPM at an 8 - 12 setting. I was also wondering what temperature thermostat you have? Mine is a 180.
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Post by 77mali on Sun May 11, 2014 11:59 am

Fish- the Monte looks awesome! Love that motor.
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Post by Fishgrinder on Sun May 11, 2014 4:01 pm

LSANTI76 wrote:At least you were fortunate to have found your braking problems in your driveway vs away from home or in heavy higher speed traffic. Brake work is one of my least favorite things to do as well. Your Monte came out very nice & I noticed you're the same 454 HO crate motor I'm running. With a 780 Holley, 2000 rpm stall, TH350 & 3.42 gears I set my initial timing @ 4 degrees BTDC & noticed I had more torque & broader power band vs an initial 8 - 12 degrees BTDC. It felt like it was running out of steam before reaching max RPM at an 8 - 12 setting. I was also wondering what temperature thermostat you have? Mine is a 180.

Thanks!

Interesting to hear you have the same motor. I've been looking into what initial timing people run on these engines, and it seems like most are up in the high range (like 14-16). I only had it at 4 deg BTDC during the first start up and never really tested the car with this setting. But does it make theoretical sense that it runs better with so little advance? Are you also using the recommended GM distributor? I like the engine, but honestly expected some more pull. It may be that my 2.73 ratio just chokes it.

Pretty sure I have a 180 thermostat as well. What operating temps are you at?

Regarding the brakes I got them bled today, and now they work as they should. More tuning up next!

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Post by LSANTI76 on Sun May 11, 2014 8:25 pm

Yeah I'm running the recommended GM distributor & also from what I've noticed from others running our same engines that like the 8 - 12 degree settings are running lighter weight vehicles that would rather have more higher RPM horsepower vs lower RPM low end torque for a heavier G3. If you are still thinking of changing out your 2.73's I wouldn't go with 3.73's unless your'e going to change to a 700r trans at some point in time. Myself I'm thinking of changing out my 3.42's back to 3.08's. Road trips @ 70 are kinda brutal & with 3.73's....well that's a few to many RPMs @ 70. As far as operating temps go I really don't know since I left my factory non-gauged dash intact & never installed aftermarket gauges. I never used to be too concerned due to running a four core radiator, HD clutch, 7 blade fan and a 160 degree thermostat. But last year I did change it out to a 180 & it seems like I picked up a little more power without overheating but I'm curious as to what engine temps are & if I could run a 190 without any problems. Although when using the factory AC & without gauges I probably shouldn't chance it.
So did you also end up using the factory 7 quart oil pan that these engines shipped with? I see like myself, you had to go with different engine brackets to install your 454. I had to & there's only about a 1/4 inch between the pan & frame.
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Post by Fishgrinder on Mon May 12, 2014 4:57 am

Hmm..maybe I'll give 4 deg BTDC a try one of these days, it's a boat of a car indeed. But that will result in a very low total timing as that GM distributor should have 22deg built in advance. My pan is the stock one, but is 6 quart and not 7 according to the spec sheet. Had to get hold of new engine clam shell mounts since I couldn't use the "make shift" ones who sat on the Buick. I think they are from a small block chevy, and there weren't any issues with oil pan clearance.

I've been thinking about 3.08 as well. It seems like a good middle way with regards to rpms. My temp gauge is still around 210-220 with the engine at operating temps. As mentioned I did measure the water hose temps with an infrared gun and couldn't find any higher numbers than 194F with the car idling. So there must be something wrong with the gauge or sensor. It would be comforting if this showed correct values though.

I'm also wondering if the transmission cooler covers to much radiator surface and reduces cooling when driving?
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Post by thatfnthing on Mon May 12, 2014 10:08 am

Fishgrinder wrote:My temp gauge is still around 210-220 with the engine at operating temps. As mentioned I did measure the water hose temps with an infrared gun and couldn't find any higher numbers than 194F with the car idling. So there must be something wrong with the gauge or sensor. It would be comforting if this showed correct values though.

I'm also wondering if the transmission cooler covers to much radiator surface and reduces cooling when driving?

The outer surface of the engine is exposed to moving air and therefore is already dissipating heat just sitting there, so the outside surface will always read slightly cooler than internal temp.  And 200-210 is about normal for a factory configuration -- the higher the temp, the better the power production, and it's also beneficial for emissions and burning off crud in the oil, so the factory designs them to run in that neighborhood.  My Silverado runs at 210 consistently.

The trans cooler should not be a problem, though if you are concerned that it runs too hot consistently, you could upgrade it to a pusher fan, get an engine fan with more blades, or upgrade to dual electric engine fans.  It's all about increasing the airflow through the radiator -- the stock unit can shed a lot of heat if you can move more air through it.
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Post by Fishgrinder on Sun Aug 17, 2014 11:48 am

A little update from this summer.

First of all, Mcarlo77 found me some new wheel well moldings and front fender molding, so now I have a complete set with exception of the short driver side rocker molding. There are some issues on how I'll attach them, because all the studs and holes have been grinded of or plugged. Also the side marker lamps have been eliminated and welded shut. But I'm in no rush with this. I think they will make the car look nicer when they are on, makes the sides look leaner.

So, I just couldn't find peace with the temperature gauge flicking above 220F at times. If going straight from the garage and out on the highway it would sometimes peak to like 240 rapidly before going back. Obviously this couldn't be the actual temperatures in the engine. The speed of needle was just to quick. Did some reading and saw many people had seen improvements after drilling holes in the thermostat. I did this, and since it hasn't gone above 220F, and mostly stays around 200-210 at highway speeds. Maybe there was air trapped in the system all the time? This i can live with.

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Next on the list was installing a tachometer, because I've given up getting the factory gauge to work. Put it on the
far side of the gauges, and I think it blends in ok.
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With the tach in place I could start modifying the ignition advance curve. I was able to put in on top of the dash facing the windshield so I could see the rpms from under the hood while using the timing light. First I checked the advance curve with everything stock in the distributor. It seemed to still advance even above 4000 rpm. My goal was to get the full mechanical advance in by 3000 rpm. Put in a complete Mr Gasket kit with weights and springs. For some reason this had the mechanical advance kicking in at idle speed regardless of what springs I used. Swapped back to the original weights and springs. When i looked closely at the stock springs compared to the ones in the kit, the stock ones are actually shorter in length. Combined with the lighter weights the after market springs fly out at idle speeds and give too much advance.

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Then I tried stock weights and Mr Gasket springs. Here I found a combination that gave me maximum advance at 3200rpms. Anything lighter would make the advance come in at idle again. Then I adjusted the initial to 20 to have a total of 36@3200rpm. I was surprised that there was only 16 initial in the distributor, because it should be 22 according to GM. Anyways, the car got more responsive with this adjustment. Next up was limiting the vacuum advance to avoid too much total at cruising speed. My canister gives 20 degrees additional, so I made a limiter of some soft metal.

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I gradually adjusted the limiter to get a total of 34deg at idle and 50deg at 2200rpm using the timing light. So this means I reduced it by 6 degrees. Must have popped the distributor lid like 15 times in this whole spring and limiter process.

During one of the test drives I had accidentally popped the hood before I drove out of the garage, and it came flying up at 30mph! Fortunately only the chrome trim on both ends was bent among with some scratches on the inside of the engine compartment. Managed to bend it back and It's hard to even notice it. I got kind of stirred up after this incident, and had to cool the nerves down at the local brewery festival afterwards.

Next up is swapping springs to get a stance similar to 1973 454Monte. Hopefully within the next months. It has sagged a lot since I put in the big block.

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Post by 77mali on Sun Aug 17, 2014 6:50 pm

Awesome job Fishgrinder. The car looks really nice!!!
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Post by thatfnthing on Mon Aug 18, 2014 9:03 am

Nice work!
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Post by 1973 454 MONTE on Mon Aug 18, 2014 11:38 am

thats looking very good. did you get the 275-60s on all 4?

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Post by Fishgrinder on Tue Aug 19, 2014 7:57 am

Yeah. I've also bought the NAPA-springs you gave me the numbers for, so hopefully it will come up in the air like your awesome 73!

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