Jim G’s SLURP Project – Posting 30: Precision Weighing of engine / trans
This posting is one in a series. If you have not yet read the earlier postings in the series, you’ll need to, as this posting won’t make much sense without having done so! Just do a search using the word “SLURP”.
In my last posting I covered some of the forensic evidence we have uncovered on Red’s earlier life. In this posting, I’ll cover an exciting new capability that I have arranged to add to my toolbox for use on this project: precision weighing of vehicle and components.
A couple of nights ago, Randy and I did some preliminary trial fitting of the engine and transmission into Red’s chassis.
In this photo, you can see how we applied masking tape so that we could lay out some basic measurements on the tape versus marking up the chassis itself:
http://i252.photobucket.com/albums/hh16/JimGnitecki/Weighingmeasuringforengine-trans002.jpgWe used dimensions from the data sheets that came with the engine mounting kits from Street and Performance, and alos dimensions that we had carefully measured and diagramed ourselves before the cab went to Restoration Specialties for body work and paint.
Next, we transferred the engine from the engine stand to the engine hoist, lowered the engine down to near floor level, and manually, and temporarily only, attached the specially built 700R transmission from Phoenix Transmission:
http://i252.photobucket.com/albums/hh16/JimGnitecki/Weighingmeasuringforengine-trans001.jpgNote the billet weigh scale platform on the floor right under the engine oilpan. This is one of 4 such platforms that, together with a computer box and 4 cables, make up the Intercomp SW500 racing weigh scale system used to weigh race cars. I have arranged for at least temporary possession of one of these systems, so I can start providing exact weights versus numbers obtained from unverifiable sources.
http://i252.photobucket.com/albums/hh16/JimGnitecki/weighing-IntercompSW500.jpgThis type of system is used mainly in two types of settings:
1) In racing, to determine, manage, and alter not only total vehicle weight, but also weight distribution and suspension settings
2) In design / development of street rods and custom vehicles, for similar, except non-competitive reasons
In all cases, the idea is to know exactly how much actual weight you have at any stage of the build, or with any specific idea or permutation or setting.
The scale systems most often used are from companies like Intercomp and Longacre, and are impressively accurate. They promise accuracy within 1/10 of one percent, or the smallest unit of display used (1 pound in most case), so the WORST accuracy is within 1 pound for any item up to 1000 pounds, and 1/10 of one percent of the item weight for any reading over 1000 pounds. I tested the system I received on my own body weight, and indeed the result obtained, no matter which of the 4 corner scales I stood on, was always within the one pound display capability limit.
We tried to weight the engine alone first, but getting it balanced on its oilpan onto one platform (or multiple platforms for that matter) by itself proved impractical. We COULD have placed a platform under each motor mount and one at the back, but it was easier to use a different approach.
We first weighed the custom 700R4 Phoenix transmission, and it sat nicely on one platform (large, flat bottom), and came in at 135 pounds. Note that the torque converter, which gets installed later, will add 44 pounds to that, so it’s actually more like 179 pounds for the “transmission in total”.
Then, we attached the transmission (withOUT the torque converter) to the engine temporarily, and were able to balance the whole assembly on the scale and got a repeatable total weight: 567 pounds.
That means the engine, which is currently NOT yet “complete”, weighs 567-135 = 432 pounds right now. This seems light, but remember that the starter (8 pounds I think I remember)), entire front end accessory drive system (“FEAD”), intake manifold and carburetors are still not on there. The intake manifold by itself is 16.5 pounds, each carb is 7.6 pounds (!) and there are 2 of them, and the air cleaner assembly is 5 pounds (with TWO stacked filters), so the engine is at 477 pounds before we add water pump, alternator, AC compressor, and the brackets to mount them, plus the serpentine belt (The flexplate is already on the engine). Therefore, the engine and tranny and converter will probably be something more than 656 pounds.
This IS going to be pretty light compared to the 261 inline six and original cast iron Hydramatic we removed. The old engine and tranny weighed well over 800 pounds. I had estimated only about a 140 pound weight saving for the engine plus tranny, so we seem to be tracking pretty much as planned.
That’s the good news.
The next posting will include some news that is not so good.
Jim G
