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Mechanical

Inexpensive Home Radiator Cleaning

Wednesday, July 18th, 2018

With most local radiator repair shops now out of business (you can buy new radiators for modern vehicles much less than repairing the originals) finding repairs for original brass radiators is very difficult. Shop repairing large commercial truck radiators still are needed but usually in only larger cities.

If your older GM original truck radiator does not leak but is cooling capacity has become limited (coolant boils on most uphill drives) there is a successful home repair.

Several Solutions:

  1. Fill your calcium clogged radiator with 50% “White Vinegar” and 50% water and let set 2 to 3 days. You will be amazed at what comes out of the core when it is drained! It will even clean the engine block and head!

This old school method has been a proven success over the years and it is very inexpensive. Check your local grocery store. Price is about $2.50/Gallon

  1. A Customer recently mentioned a household cleaning solution sold at hardware stores and some larger grocery chains called CLR. (Calcium, Lime and Rust) CLR appears to be made stronger than white vinegar and it is also diluted 50% with water. Description shows removing these unwanted scale deposits. .

Radiator shops usually use long small diameter brushes to “rod out” the calcium build up in the tubes. If they puncture a cooling tube with fins, they block it off with solder, and also solder the upper and lower damaged tanks back in place. You will never know how many have been soldered shut. The new black paint covering the radiator.

Save your cooling tubes with fins. White vinegar or other liquids may be the way to go!

 

An Extra bonus: If you place is solution in your drained radiator and let it set, it will also remove calcium build up in your engine block. Thus, the block has more flowing water and operates at a cooler temperature.

1960-66 GMC V-12 Engine

Monday, July 2nd, 2012

1960-66 GMC V-12 Engine

Forgotten by most is the gasoline V-12 engine made by the GMC Division of General Motors in the mid 1960’s. This very large one piece engine block was made for GMC’s largest trucks. Examples of these vehicles were water carrying fire trucks and off road vehicles such as quarry trucks, which hauled tons of rock. As can be imagined, the pulling power of these trucks must have been at the top of GMC’s fleet.

Unfortunately, due to the weight of the truck and engine, most were sold to metal recyclers when their working days were over. Most of the few remaining V-12 engines are in fire trucks that have been used only during fires or fire training.

The attached photos show a ½ ton 1964 GMC with one of these V-12’s made to fit for display at shows. Owner unknown. What a mechanical project to fit it into a small ½ ton.

As far as gas mileage, we suspect they almost have to pull a gasoline trailer to keep the engine supplied!

1960-66 GMC V-12 Engine 1960-66 GMC V-12 Engine
1960-66 GMC V-12 Engine 1960-66 GMC V-12 Engine

Speedometers to Go…

Monday, August 15th, 2011

Rebuilt Speedometers for Chevy Trucks & GMC Trucks

When your older truck needs a rebuilt speedometer, think of us! Our company, in combination with a local specialized shop, provides a quality product that you will be proud to place in your vehicle.

With most new repair parts, no longer available, we obtain used speedometers from across the country. Only the best parts are removed. These are combined with available new components to create a quality finished product. The following photos show various stages in the repair process.

Speedometers

Work Bench

Parts Inventory

GMC 302 Install in Old Chevrolet

Thursday, February 11th, 2010

The Trials and Tribulations of Installing a GMC 302 engine into a 1950 3/4 ton Chevrolet Pick Up

by Joel Baumbaugh

Background: About 5 years ago I “upgraded” the engine in my truck from a 216 to a 235. Lately I have felt that I wanted/needed a little more torque (especially while the bed is full of something heavy) and while one option was to rebuild and re-cam my 235 and another was to install a Chevy 350/400 (or 700R), the “popular” literature said that I could also install a GMC 270 or 302. Just to be “different”, I decided to go the latter route.

The Source: I wanted a “running” engine that I could just drop in with a minimum of trouble. The engine I found for my project was a 1959-1962 GMC engine from a School Bus. The bus had been converted into a “camper” and had then caught on fire and burned beyond repair. At first glance, the outside of the engine looked kind of rough. I checked the compression (all cyls. were at 160 lbs./sq.in), looked at the plugs (all light brown), listened to it run (no strange noises) ‘ the oil pressure was 55-60 lbs./sq.in. at idle and the rocker arms/valve area was pretty clean of sludge. Short of pulling the pan, this was as far as I could go. I bought it, brought it home and cleaned it up.

Problems/Solutions: The engine had a LOT of bus-type accessories that I did not want/need. The “massive” front Crank Pulley (the damper pulley assay) had a three-groove pulley ‘ “way” too long! After careful measurement I found that I was able to replace it with a single groove pulley off of a 235 (I replaced the front seal at this time). The water pump shaft was “very” long as well and sported a 2-groove pulley. I removed the pulley and ground/cut the pulley shaft back. The water pump on this engine did not seal against the block and/or head. This one was bolted to a thick steel plate which held a tensioner (for a double groove pulley) which weighed about 30 lbs. (weight I did NOT want) and was bolted to the front of the block. I found a rear plate (and gaskets) for the water pump from a place here in town that rebuilds water pumps. Bolting the water pump directly to the block saved me another ½ inch in engine length. The owner also sold me a flange to press on to the shaft so that I could bolt a new water pump pulley onto the pump (the original Chevy is shaft diameter is ½ inches and the 302 is 3/l8 inches). To find a pulley which would align with the bottom crankshaft pulley required a number of trips to local junk/wrecking yards. I finally found one that was the perfect depth (I’m not sure if it was originally from a Chevy or not). I had to enlarge the center hole to make it fit the GMC shaft.

The 302’s “bus” generator weighed about 80 lbs. I found that the 235’s generator mounting flange’s bolt-holes fit perfectly! However, I “did” need to reverse it and then elongate the mounting holes so that I could slide it forward to align the generator pulley groove with the crank and water pump pulleys.

The carburetor that came with the engine was a joke. It even had a governor on it. I had the option to purchase a better 2-barrel carburetor or to step up a little bit and buy a 4-barrel manifold. I did the latter. I had a (gasp) Ford ‘Autolite’ carburetor in my garage (about 400 CFM) from a ‘289’ which I bolted up to the manifold and it works GREAT! – Especially with the stock low-performance camshaft. I also at this time “upgraded” my carburetor linkage. I went to an off-road dune buggy place and purchased a new accelerator pedal and a push-pull cable. Configuring the carburetor linkage from the stock pedal to the new manifold/carburetor would have been a nightmare otherwise.

Radiator: The 302 engine “is” 1 1/2 to two inches longer than the 325 (which is longer than the 216). This means that the radiator no longer fits into its original location. I tried to modify the radiator mount to put the radiator inside. Don’t even try. The radiator needs to mount on the front of the mount. This means that you will have to borrow your neighbor’s “Saws-All” with a metal cutting blade and cut away the top and front cross bracing on the radiator support, the lower front wind deflecting metalwork at the bottom (behind the grill) and drill 6 new holes in the mount for the radiator. The upper support that contains the hood latch will need to have a rectangle cut in it to fit the top of the radiator in it as well. I now have about 2 inches clearance between my water pump pulley and the radiator. I use an electric thermostatically controlled (pusher) fan in front of my radiator. It’s quieter, doesn’t rob the engine of power (better mileage) and the water pump may last longer without the fan blades. Note: My friend and neighbor has a 1951 GMC. I have measured his engine compartment. From his bellhousing to the radiator flange he had 4 more inches to play with, so I’d bet that he originally had a longer GMC engine (he runs a Chevy 235 now), and that he could make the conversion to a 270 or 302 without any cutting being necessary.

Front Mount Yes the 302 engine “is” 1 1/2 to 2 inches longer than the 235. The front mount on the Bus’ 302 was a weird set-up which caused the engine to sit at an angle (like a Chrysler slant 6). This saved some height in the bus’ engine compartment. However, after removing the bus setup spacers, I found that the two bolt holes on the mount (on the bottom of the timing cover/block) were at right angles to the block and aligned perfectly with my truck’s original 216 mount so I was able to exchange them and everything was level ‘ no oil pan removal required! I then drilled two (new) holes through the truck’s cross member, put in longer frame-mounting bolts and added some extra rubber padding (cut from a truck mud-flap) to keep the mount from rubbing on the frame and so far its worked ok.

Rear: The bus engine I purchased was coupled to an automatic transmission. That meant that it had a flex plate (that the converter bolted to) instead of a flywheel. The flex-plate (with the old ring-gear) was MUCH larger than the flywheel I would need. I found a flywheel from a GMC 270 that fit. Although the flywheel’s diameter and the number of teeth are the same as the 1955-1959 Chevrolet, the crankshaft bolt pattern is different between the GMC’s and the Chevrolet’s. The flywheel bolts are different as well (1/2 inch dia. instead of 3/8’s”). Although I tried using an impact wrench, a gorilla on steroids must have put on the old flywheel bolts. I broke a socket and finally had to remove 3 of them with a chisel. The 3/8″ GMC flywheel bolts are not available ANYWHERE. I went to an industrial bolt supply place and bought six more grade 10 bolts. I had the heads machined thinner (like the originals) as otherwise they protrude into the pressure plate/clutch plate area and will cause binding problems. I then carefully shortened the bolts (watch those threads ‘ I put a tap on the inside of the bolt and then backed it off to remove the burrs) to match the original length as they otherwise hit the block behind the flywheel (close tolerances here…).

The pressure and clutch plates and throw-out bearing match those of a Chevy 1955-1959 10- inch set. The 302 had a roller bearing pilot bearing instead of a oillite bronze bushing. I replaced it with another roller bearing and the transmission (its a Saginaw off of a 1969 Camaro) fit in just fine.

I used my original bellhousing off of the 1950 Chevy. The old GMC one was slanted to match the front motor mount. The starter location in the GMC bellhousing was for a larger diameter flexplate and would not work. The GMC starter had the wrong number of teeth to work on the 10″ flywheel. The starter which (I found) works, was a 12 volt 9 tooth (for a 164 tooth flywheel) from a 1955 Chevrolet and works great.

Oil and Water lines: There is an oil line on the front of the block up to the head. This supplies the oil to the rocker arms. Leave it alone. I tied (T’d) into it and put on a 100 PSI oil pressure gage as my Chevy gage only goes to 30 lbs. This engine NEEDS an oil filter. If you block off the oil supply line on the driver’s side of the block you will not get ANY oil pressure in the engine. I “T’d” into the pressure side and connected up my original oil pressure gage (it’s a stretch, but it reaches). Yes, it’s always pegged on 30 lbs., but gives me a warm fuzzy feeling when I look down. The head has an external water line that goes to the thermostat housing. Leave it alone. You can put a “T” in and hook up your temperature gage (with an adapter), but I put mine further down on the block (there’s a fitting there), because it was always showing “cold” on the gage. Be careful of that temperature gage line. It cost me close to $50.00 the last time I had to replace it. The radiator hoses clamped right up although the GMC diameter on the lower radiator hose is one step smaller.

The 302’s distributor had a governor on it and was centrifugal advance only. The bottom of the distributor was different than the Chevy, but my Chevy distributor “guts” bolted right in. I was able to put in a spring kit (the GMC centrifugal advance springs were so thick that they could have been used for front struts on a Honda) and I now have vacuum advance as well.

The GMC fuel pump leaked so I replaced it with a Pep Boys electric fuel pump. I couldn’t find a replacement anywhere locally, so I guess I’ll have this one rebuilt for a “spare”.

I had a split cast-iron exhaust manifold on the Chevy 235. I “may” get a header for this motor in the future, but in the mean time I had the muffler shop split the 302’s three-inch header pipe into the two existing exhaust pipes.

And, how is it?

Well, pretty good. I have a LOT more torque. This means that I can get up to freeway speeds without wishing for bike-pedals for a little more push. I have 36″ tires on 6″ Chevy rims on the back so I’m only turning 2,800 RPM at 60 mph. The larger tires had made the truck a little “logy” getting started with the 235 ‘ now it “steps right out” from a light. I haven’t checked the gas mileage yet. I was getting 17 mpg City and 20 mpg highway with the old 235. I’d guess that I’ve lost about 2 mpg with this engine/carburetor combination.

Future When this old engine is due for a rebuild, I’ll probably buy some “lighter” pistons and a little hotter (than stock) cam. The pistons will help the engine “rev” faster, be easier on the bottom end and will probably result in higher gas mileage due to their weight difference and the higher compression. The cam will help volumetric efficiency and give me a little more torque and higher end. Of course I’ll have everything balanced ‘ IMHO it’s worth the extra money.

I hope that this story helps someone else. Remember the 270 and 302 are “basically” the same engine so I imagine that your situation will be pretty similar to mine no matter what you find. It took “6 hours” using hand tools to remove the old engine and 4 days to put back in the new.

Joel

UPDATE

Since the project above, I decided to rebuild the 302 as it was burning a little oil. I bored the cylinders out .125 thousands (it’s now 320 cubic inches), put in a “Patrick’s” M4F camshaft, and put in “Venolia” 10.5×1 forged pistons. I had everything balanced of course. I had to find and purchase another head as the old one had a crack in it (hence the oil burning). When I got the new (used) head, I pulled out the valves and cleaned/smoothed up the intake and exhaust ports/passages which were pretty rough castings, and then put in new late-model exhaust valves (I went to 1.5″) and hardened seats for unleaded gas, and I’m using Chrysler “440” valve springs. I’m now running a “Holley” 600 CFM carburetor (vacuum secondaries) with “Fenton” cast-iron headers. When first started up on a dyno (and not really broken in yet) it recorded 286 hp and 362 ft/lbs torque; not bad for a “street” engine; At this time I also put in a T-5 GM transmission from a ’91 V-8 Camaro (the V-8 transmission has better bearings to handle the torque) with a tail-shaft from a S-10 Pick-up (the shifter was almost in the same place) – so now I have a 0.74 overdrive. At 75mph (a fender-slapping speed for the old pick-up) I’m only turning 2,100 RPM; I had a new driveshaft made as the transmission yoke splines on my old one looked worn.

So far, I’m pretty happy with my set-up. Happy “wrenching” everyone;. ..jb

Joel Baumbaugh

Casting Numbers

Thursday, February 11th, 2010
Casting Number Make Year CID
1970 Chevrolet 1964-1967 292
2135412 GMC 1946-1954 248,270
2193980 GMC 1952-1954 302
2324003 GMC 1955-1963 270
2324004 GMC 1955-1962 302
2404929 GMC 1955-1963 270
2192402 GMC Military 302
289890 Chevrolet 1963-1977 292
328575 Chev/Buick/Olds/Pontiac 1968-1984 250
328576 Chev/Buick/Pontiac 1968-1976 250
328880 Chevrolet 1963-1977 292
329990 Chevrolet 1963-1977 292
358825 Chevrolet 1966-1976 250
3629703 Chevrolet 1950-1952 235
366855 Chev/Buick/Olds/Pontiac 1966-1984 250
3692703 Chevrolet 1950-1952 235
3692708 Chevrolet 1950-1952 235
3692713 Chevrolet 1950-1952 235
3693374 Chevrolet 1942-1949 235
37001481 Chevrolet 1953-1955 235
3701946 Chevrolet 1953 235
3703414 Chevrolet 1954-1956 261
3733340 Chevrolet 1955-1957 261
3733813 Chevrolet 1958 261
3733946 Chevrolet 1954-1955 235
3733949 Chevrolet 1953-1955 235
3733950 Chevrolet 1954-1955 261
3737012 Chevrolet 1955-1957 261
3738307 Chevrolet 1958-1962 235
3738365 Chevrolet 1960-1962 261
3738476 Chevrolet 1958-1962 235
3738813 Chevrolet 1955-1963 261
3739365 Chevrolet 1958-1962 261
3739716 Chevrolet 1958-1962 235
3759365 Chevrolet 1959 261
3764476 Chevrolet 1958-1962 235
3769716 Chevrolet 1958-1962 235
3769717 Chevrolet 1959-1962 261
3769925 Chevrolet 1958-1962 261
3773949 Chevrolet 1954 235
3782856 Chevrolet 1962-1967 194
3782858 Chevrolet 1962-1967 194
378307 Chevrolet 1960-1962 235
3783949 Chevrolet 1953-1954 235
3788378 Chevrolet 1962-1974 292
3788406 Chevrolet 1962-1969 230
3788514 Chevrolet 1962-1970 153
3788813 Chevrolet 1955-1959 261
3789404 Chevrolet 1963-1976 292
3789412 Chevrolet 1963-1966 292
3789716 Chevrolet 1963-1972 292
3792852 GMC 1962-1966 194
3792858 Chevrolet 1962-1967 194
3821970 GMC 1967-1972 292
3833057 Chevrolet 1962-1970 191
3833067 Chevrolet 1963-1970 194
3833340 Chevrolet 1955-1957 261
383340 Chevrolet 1955-1957 261
3835253 Chevrolet 1942-1953 216
3835309 Chevrolet 1942-1949 235
3835335 Chevrolet 1942-1949 235
3835353 Chevrolet 1948-1952 216
3835363 Chevrolet 1954 235
3835374 Chevrolet 1942-1949 235
3835491 Chevrolet 1954 235
3835497 Chevrolet 1942-1953 216
3835527 Chevrolet 1951 216
3835692 Chevrolet 1950-1952 235
3835794 Chevrolet 1942-1953 216
3835846 Chevrolet 1953 235
3835849 Chevrolet 1942-1953 216
3835894 Chevrolet 1953 216
3835911 Chevrolet 1953-1955 235
3835917 Chevrolet 1954-1955 235
3835946 Chevrolet 1953 235
3835949 Chevrolet 1954 235
3836012 Chevrolet 1955-1957 261
3836223 Chevrolet 1955-1957 235
3836233 Chevrolet 1955-1957 235
3836340 Chevrolet 1955-1958 261
3836386 Chevrolet 1955-1957 235
3837004 Chevrolet 1955-1957 235-261
3837012 Chevrolet 1955-1957 261
3843363 Chevrolet 1953-1955 235
3850817 Chevrolet 1962-1978 230-250
3851656 Chevrolet 1963-1972 292
3851659 Chevrolet 1963-1976 292
3851859 Chevrolet 1963-1972 292
3854036 Chevrolet/Olds/Pontiac 1962-1976 230-250
3855914 Chevrolet 1963-1966 292
3855987 Chevrolet 1963-1971 292
3855991 Chevrolet 1963-1970 230
3856233 Chevrolet 1955 235
3858190 Chevrolet 1954-1955 235
3877178 Buick/Olds/Chev/Pont/GMC 1962-1978 230-250
3879875 Chevrolet 1962-1970 194
3886061 Chevrolet 1963-1966 292
3890011 Buick/Chev/Olds/Pontiac 1968-1972 250
3890013 Chevrolet 1968-1972 250
3892858 Chevrolet 1964-1967 194
389770 Chevrolet 1942-1951 216
3897702 Chevrolet 1942-1953 216
3921770 Chevrolet 1966-1976 292
3921967 Chevrolet 1964-1969 230
3921968 Chevrolet 1964-1976 230-150
3921970 Chevrolet 1963-1976 292
828575 Chevrolet 1972-1977 250
837751 Chevrolet 1942-1949 235
839770 Chevrolet 1942-1953 216
8397715 Chevrolet 1942-1949 235
839910 Chevrolet 1942-1951 216
839931 Chevrolet 1942-1949 235
8994256 Chevrolet 1964-1977 292
9890043 Pontiac 1968-1969 250

1938-1953 Clutch Disc

Thursday, February 11th, 2010

Chevrolet introduced their basic nine inch single disc clutch and corresponding diaphragm pressure plate in 1938. This pair was used in their cars and most 1/2 ton pickups with three speed transmissions through 1953. With about one million of these vehicles sold annually, one can quickly realize the high numbers of this clutch system that was at one time on the highway.

Even in 1954 with the introduction of the larger 10 inch clutch disc and modified pressure plate on the new 235 six cylinder, the original design continued to sell very well as aftermarket replacements. Today, they still have a strong demand even though the majority of these over fifty year old vehicles are history. Most auto part stores now keep a pair in inventory for their walk-in customers.

1938-1953 Clutch

To add even more validity to this clutch’s durability, GM reintroduced it in the late 1960’s. General Motors was a major producer of full size passenger buses and the demand for most having the optional air conditioning was becoming strong. Almost all new buses would now be equipped with the option. The original small nine inch clutch was combined with the newly engineered large bus AC compressor. Once again, this proven clutch was serving automotive needs!

Therefore, if you find a source for new or core clutch assemblies used from the late 1960’s to at least the mid 1970’s in GM buses, they will also fit 1938-53 cars and small trucks.