1942 ford 1.5 ton

CajunCrawfish

CajunCrawfish

Member
Purchasing a 1942 ford 1.5ton and have some flat-v8 questions:
  • I have been in formed that the crank and water pumps are the weak link in the power plant? Is this true?
  • Looking to keep the original motor but want to make it durable enough for daily work. Is this realistic without bottomless pockets?
  • Checked Egge Machine, HNH Flatheads and a few more. Are there any you all recommend?
  • Ford 302 is definately a workable mill but would like to have a workable flathead.
 
I don't believe the crank or water pumps are much of a problem if ever. Heat/cooling are the weakness of a flathead V8 from my experiences. Otherwise, I havn't had many problems with the ford flathead V8. If put together correctly, it should be a reliable engine for daily use.
 
Hi; There were two V8 engine options, as I recall; 85 and a merc 95hp. The merc option had a heavy crankshaft also. These trucks worked all their lives very well. The Military model was a G8T, during the war. Later Newc
 
I'm not the most knowledgeable flathead guy out there but I've never heard of crank failure on a flathead. As for the water pumps, over time they can develop leaks due to corrosion in the bushing/bearing/shaft area. These can be rebuilt or easily replaced.

The most problematic issue you might discover is a cracked block. Early flatheads had more problems with overheating due to core shift and trapped sand during casting but those problems were ironed out by 1942 although an abused engine might exhibit these signs. Cracks usually appear near the valve seats. A cracked block isn't always total loss...there are ways to fix this problem. Finding a replacement block if you need to isn't too difficult yet...engines are up for sale all the time.

I've got 2 flatheads which are very old rebuilds/refurbs. Neither have any issues (overheating, poor vacuum, weak cylinders) and are quite reliable. My experience suggests that your ignition circuit, fuel system and carburetor will affect your reliability more. Clean, rebuild and tune these items and you should have trouble-free service.

Lastly, the big truck stock 4-speed trans and rear axles (single-speed or 2-speed) keep the overall speed down. A smooth running truck probably will have a top speed of 45-50...the gearing is just too low to go faster without punishing the flathead. Even swapping to a 302 is going to make that engine work hard at high speeds. My '47 COE stakebed is very reliable, just not fast...take your time and it will work well.

COE Dan
 
I second Dan's remarks about the flathead. I've got a 1940 Tonner with the flathead and I believe its a decent engine for a truck application. If you send the engine out for rebuild you're probably looking at $2,500 - 3,000. You can do it yourself, but will need some tools unique to a flathead. You can improve driveability by changing the 4.86 rear end gear ratio to 4.11's. and the 4 speed knuckle buster to a 3 speed synchro. The big trucks have fan shrouds that direct air thru the radiator. That and a pair of Skip Haney rebuilt pumps should keep the cooling reasonable. Plenty of knowledgeable folks here on the Barn that can steer you right.
 
One more note...the 1.5 ton and 2 ton trucks have different rear axles. In fact, the only difference between a 1.5 ton truck and a 2 ton is the rear axle to my knowledge.

1.5 ton trucks were equipped with the single-speed rear axle which had the following ratios available: 4.11, 4.85 and 6.67. I can't confirm this off-hand, but I think all the 1.5 ton trucks had the 6.67 ratio. The 3/4 and 1 ton (or Tonner) likely had one of the other ratios.

The 2-ton trucks had the 2-speed axle with the following ratios: high was 5.63; low was 8.11 (yikes!).

Depending on the type of axle, you can figure out engine rpm for a particular speed with these numbers. Note that all transmissions, whether 3-speed or 4-speed had a top gear of 1-to-1.

Hope this helps...

COE Dan
 
Thanks COE-DAN and all that replied. Awesome to here the flat v8 will not have to be replaced. Thinking of solving the engine revs with an old brownie-box/ auxiliary gear box at a cost of $500.00. However if I save my pennies a little longer I think the planetary style push button unit by gearvender at an aditional $600.00 is worth not blowing the engine or breaking other parts and the cost of there repair either. Bolts directly to the back of the trans. May have to update the trans to a little newer unit to do so. Still the long range savings in truck repair and feul economy are a good trade. AWESOME-BARN!
 
Cajun, it sounds like you got your advice from a Chevy guy! lol

You won't blow up a flathead from high revs - they run out of breath before damage can occur.

The waterpumps and crank have 70 years of hard working history - more than we can say for the sbc or sbf. Stick with the flathead and you'll love it!
 
CajunCrawfish said:
Thanks COE-DAN and all that replied. Awesome to here the flat v8 will not have to be replaced. Thinking of solving the engine revs with an old brownie-box/ auxiliary gear box at a cost of $500.00. However if I save my pennies a little longer I think the planetary style push button unit by gearvender at an aditional $600.00 is worth not blowing the engine or breaking other parts and the cost of there repair either. Bolts directly to the back of the trans. May have to update the trans to a little newer unit to do so. Still the long range savings in truck repair and feul economy are a good trade. AWESOME-BARN!
Click to expand...


gears14.jpg
Gear vendors auxiliary drive. My price was a lot off but still worth keeping the old metal running without extra stress of todays demands.
 
Cajun,

Can you pass the part number/model number on that Gear Vendors auxillary? If it's an easy bolt in, I might go for something like that. I don't know if it will fit in my COE though. I have the short wheelbase (101 inches) version which has an obviously short driveshaft. This auxillary might be too long to get acceptable geometry.

There were several companies that made aftermarket transmissions that were a bolt-in to Fords. One is a 5-speed overdrive (.799 to 1) built by Clark with a model number of 205VO and distributed by Truckstell. I've never seen or heard of one for sale but there it is if you find it.

COE Dan
 
COE Dan said:
Cajun,

Can you pass the part number/model number on that Gear Vendors auxillary? If it's an easy bolt in, I might go for something like that. I don't know if it will fit in my COE though. I have the short wheelbase (101 inches) version which has an obviously short driveshaft. This auxillary might be too long to get acceptable geometry.

There were several companies that made aftermarket transmissions that were a bolt-in to Fords. One is a 5-speed overdrive (.799 to 1) built by Clark with a model number of 205VO and distributed by Truckstell. I've never seen or heard of one for sale but there it is if you find it.

COE Dan
Click to expand...


Part #3D0435A

Manual 4-Speed NP 435.
Replaces 4 3/4" tail-housing.
Cost is really high but it will save the vintage parts and fuel economy. I will look into the truckstell.
 
Looks like my original trans because of the bell-housing being part of the trans and brake on the back of the trans will have to be replaced in order for me to use the Gear Vendors auxiliary. Looks like NP435 or T18-T19 Transmissions are my possible suiters. Good thing is they are syncronized transmissions. Now the bad news: all the adapters I have found have been flat-v8 to gm-transmission adapters Like the one below. I know the NP435 has both a GM and Ford version and my only other option because of the adapter is a GM SM-465. Want to stay with a ford trans.
http://www.speedwaymotors.com/Garag...To-Flathead-V8-Adapter-Ford-Clutch,58485.html

http://www.speedwaymotors.com/Offy-GM-Manual-Trans-to-Flathead-V8-Adapter-Ford-Clutch,812.html

http://www.speedwaymotors.com/Speedway-GM-Manual-Trans-to-Flathead-V8-Adapter-GM-Clutch,11098.html
 
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