Ford 7.3L V-8

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mikemc53

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Feb 28, 2014
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Just curious how this engine has been performing for anyone that has it - particularly if they can compare it to the V-10. The drive-train itself actually as I believe they upgraded the trans also. I just bought a Class C with the 7.3L and I'm curious to hear what others think of it. I currently also have a Class A with the V-10 which I will be selling but comparing the two would be less than clean seeing as how the Class A is older and considerably bigger than my new Class C.

Thoughts?
 
The 7.3L Ford engine replaces the V10 which is a good engine but fuel hungry, loud, and needs high revs to reach it best torque. The 7.3 was designed to have a lot of low rev torque similar to a diesel engine characteristics. It is also better on fuel consumption than the V10.
 
I am glad Ford got rid of the V10. I thought it was a dumb choice for an RV engine. High RPMs, too many parts, small size (around 415 CID or 6.8L), sucks in gas for nothing. When I bought my RV (listed below) I went out of my way to avoid the V10. Somewhat difficult as around 90% of RVs had that Ford V-10 at the time.

With the new 7.3L, I can now consider Ford for my next RV.

IMO, they should make a very large V-6 for RVs. Makes more sense to have less cylinders for an RV engine, but with a large size, around 8.2L or around 500 CI or so.

-Don- Reno, NV
 
DonTom said:
IMO, they should make a very large V-6 for RVs. Makes more sense to have less cylinders for an RV engine, but with a large size, around 8.2L or around 500 CI or so.

-Don- Reno, NV
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The reason Ford went to the V-10 was they found a large bore caused incomplete combustion, resulting in unburned fuel passing out the exhaust. This raised the hydrocarbon count and kept the 460 from meeting stricter emission requirements, so they added 2 more cylinders to keep the bore below the critical diameter. Besides raising the emissions, the unburned fuel helped give the 460 the reputation of being able to pass anything except a gas station.

Apparently they were able to solve this problem in the 7.3L engine but I don't know if it could be scaled up any further.
 
I'll take my V-10 any day. :) The 7.3L V-8 still has a bit to prove, in my book. I like the design though. Will likely mate a 10sp auto tranny to it in the near future. Don't they have the 7.3 in a superduty with a 10sp?
 
Yes, the 7.3L is mated to the 10 speed transmission in most applications, but for some reason they decided to keep the 6 speed in the F53 chassis.
 
The primary value of the expensive 10-speed is improved fuel economy, i.e. always keeping the engine rpm in optimal range. Worth the extra cost on a car or SUV that must meet a CAFE mpg target and customer mpg expectations. Note that the 10 speed is basically the same top & bottom gears, but more choices in between.

In a large & heavy motorhome that typically doesn't do stop & go driving, extra speeds don't help the mpg much, and the top gear only gets around 9 mpg at best anyway. 4 extra gears for fine tuning between top gear and low add cost and complexity for almost zero gain in overall mpg. Just not a good engineering cost trade-off. Since Ford has a perfectly good heavy duty 6-speed in the parts bin, they use it. Eventually they will probably discontinue the 6-speed and replace with the 10 simply to reduce the amount of unique parts they have to build, but for now the 6-speed will likely stick around awhile.
 
Ford is currently offering the the entire line - F350-600 with the 7.3 V-8 and 10 sp auto trans. The F600 has a 22000lb. GVWR.
 
I don't think it's a works vs doesn't work issue - it's just a bit easier to get a full burn in a narrower bore. There are many other pros and cons of higher vs lower revs, bore vs stroke, and more vs less cylinders. Engine designers balance a variety of factors to get the desired results at an acceptable cost.
 
Gary RV_Wizard said:
it's just a bit easier to get a full burn in a narrower bore.
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One would think a full burn would give better MPG, but for the small size of the V-10 engine, it sure is poor.

It could be easier, but even Harley has no problem with large cylinders making smog specs. My Harley is 107CI / 1.753L.

53.5 CI / 0.8767 per cylinder with the Harley.

45.15 CI / .74L per cylinder with my RV 7.4L engine.

41.49 / .68L per cylinder with the V-10 (6.8L engine).

And these days, they can really make a low number of cylinders very smooth. When my 2-cyclinder Harley was first designed, the Harley engineers thought it was way too smooth. So they went from 100% balancing in the engine to 75%. That was so their "riders would know they are on a motorcycle".

But I guess a 6 cylinder RV is out of the question for an RV because of the smog requirements. The same size cylinders as my Harley would only add up to 5.26L in a V6, engine, a bit small for an RV engine.

-Don- Reno, NV
 
It's worth noting that GM's "big V8" is now a 6.0L. And nobody makes an engine with gas-powered RVs in mind - not enough sales volume there to justify any special requirements.

Also worth noting that the diesels used in motorhomes are all 6 cylinders and inline.
 
The largest GM V-8 gas engine is actually a 6.6L now. Yes it is confusing because the diesel is also 6.6. Not sure the specs on the new 6.6 gas engine but probably better than the 6.0.
 
As far as I know the new Chevy class C's still have the 6.0. The few that they make now. Not sure when/if they will ever get the 6.6. Will probably happen eventually or Chevy just may not offer that chassis for RV's anymore. Nexus does have the new Rebel 4x4 which is basically a Chevy chassis with the Duramax 6.6 diesel.
 
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