j-d
Sunny Florida USA
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Can't help with cams... But we swapped the 318 out and 360 in, with passenger's seat, door, and front wheel removed. Placing the jack stand to clear the hoist was a little tricky. Accessories, carb, exhaust, distributor and water pump were off. Water pump is LONG, has to be off.
Part of why the door, I didn't want to tear the A/C apart. The aftermarket unit was all done in hose, so I tied the compressor out of the way and left it charged.
Is this swap going to be one 360 to another 360? I ask because 318 and 360 use different brackets to the front motor mounts. Luckily I came across a parts van.
Either small block to a big block presents still more issues. Griff can go into detail. I'm just glad I didn't try it.
* This post was
edited 06/04/18 12:35pm by j-d *
If God's Your Co-Pilot Move Over, jd
2003 Jayco Escapade 31A on 2002 Ford E450 V10 4R100 218" WB
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Griff in Fairbanks
AK
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j-d wrote:Can't help with cams... But we swapped the 318 out and 360 in, with passenger's seat, door, and front wheel removed. Placing the jack stand to clear the hoist was a little tricky. Accessories, carb, exhaust, distributor and water pump were off. Water pump is LONG, has to be off.
Is this swap going to be 360 to another 360? I ask because 318 and 360 use different brackets to the front motor mounts. Luckily I came across a parts van.
Either small block to a big block presents still more issues. Griff can go into detail. I'm just glad I didn't try it.
Will go through the planning process for MLP shortly ... all experts tell me I did it right.
Engine swap -- had issues with brackets on an engine swap with a '65 GMC step van ... haven't had any issues with MLP's 'chassis' ... which involved swapping a 440 out and 318 in. Had to swap brackets on frame but otherwise everything fit just fine.
So a small block (318) to a small block (360) should be smooth.
As far as I know, the only significant difference between a 273/318/340 and a 360 is the crank journals and oil pan.
I believe there are differences in oil pickup and pans between truck and automobile versions of small blocks (273/318/340/360).
Vintage Mopar -- please chime in and correct me if I'm wrong.
1970 Explorer Class A on a 1969 Dodge M300 chassis with 318 cu. in. (split year)
1972 Executive Class A on a Dodge M375 chassis with 413 cu. in.
1973 Explorer Class A on a Dodge RM350 (R4) chassis with 318 engine & tranny from 1970 Explorer Class A
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j-d
Sunny Florida USA
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Ah yes, old memories. The 360 came out of a car and the oil sump was at the other end of the pan from the 318 from the van. I think I had to buy a new oil pump for the 360 and re-used the pan from the 318... I think...
Both engines had u-shaped brackets between engine and rubber mount. The 318 and 360 were different. I forced 318 to work, then was able to get 360 brackets.
318 engine is internally balanced. So use the 360's harmonic balancer on the 360, don't swap the one from the 318 over. 360 needs a weight spot welded onto the torque converter from the 318. I chose not to do that and instead got the converter from a 360 with weight already there. Problem was, it was a high stall car converter and slippage at highway speed under load was so great that I burned a transmission out. Problem with adding the weight is that the 318 flex plate and torque converter match up in any "clocking" since balance doesn't matter. Since 360 DOES matter, some kind of compatibility issue came up there. I forget those details.
That said, a 318-to-360 swap IS worth it. Dodge's claim that their 318 matched GM's 350 was FALSE. 360, yes.
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Griff in Fairbanks
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j-d wrote:Ah yes, old memories. The 360 came out of a car and the oil sump was at the other end of the pan from the 318 from the van. I think I had to buy a new oil pump for the 360 and re-used the pan from the 318... I think...
Nope, 273/318/340 oil pan won't fit a 360. Rear seal has a larger diameter.
Otherwise, accurate.
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Griff in Fairbanks
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j-d wrote:Both engines had u-shaped brackets between engine and rubber mount. The 318 and 360 were different. I forced 318 to work, then was able to get 360 brackets.
Need right combination of engine brackets, rubber mounts, and frame brackets. These can, for the most part, be swapped around.
In my 440 to 318 swap, I had to the swap frame brackets and flip the rubber mounts over. Everything fit better than Simpson's glove.
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Griff in Fairbanks
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Grab a cup (and fresh pot) of coffee and get comfortable ... 'cause here I go again.
My Little Project (MLP) is the latest iteration of a desire of mine that's spanned almost a half century.
One of the primary goals of MLP is 20+ MPG out of a Class A motorhome.
Engine (and transmission) is a 318-3 out of a 1969 M300 Class A. 'New' chassis is a 1973 RM350 Class A with the next longer wheelbase than the M300.
I had used the M300 (and OEM 318-3) for several thousand miles in Alaska's often mountainous terrain. (What Lower 48 people -- especially on the east coast -- call mountains we call hills.) I was very satisfied with the performance and I have a soft spot in my heart for the Mopar 318. (Some of you may say I "have a soft spot in my head" ... I'm comfortable with that.)
OEM 318-3 had leaded gas heads. The heads were also a special, late-60's 'cold weather package.' Instead of re-routed exhaust, these used engine coolant to preheat intake manifold. So heads and two-barrel intake manifold absolutely must be used together. (Special 'cold weather package' was only offered for two or three years so the heads/intake manifold combination is extremely rare.)
I wanted a four-barrel carburetor instead of the OEM two-barrel Carter BBD. So, in addition to unlead gas heads, I needed a different intake manifold.
I found a set of unused -- never had valves in them -- unleaded gas 318 heads on eBay. Heads had been sitting on a shelf in an Air Force warehouse for decades. Seller was in Nevada, heads were in California, the people I wanted to build the heads were in Maine, and I was/am in Alaska. I bought the heads, had the seller ship them to Maine, where the engine builder checked them out before the sale was final. (I wish I could have gotten 'airline miles' for heads ... California to Maine to Alaska.)
To be continued ...
* This post was
edited 06/04/18 03:54pm by Griff in Fairbanks *
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Griff in Fairbanks
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When planning a project like MLP, far too many people start with the engine and work their way back to the rear wheels. Then, they wonder why things don't turn out the way they'd hoped/wanted.
Recommended (and most effective) way is to start with the rear tires and work your way forward to the engine.
The majority (roughly 80 percent) of MLP's use will be highway miles at 55-65 mph ... so we want to select the combination of engine parts that are most efficient at the engine RPMs that match the tires, gearing, and vehicle speed.
It's important to remember, as I've said sooo often, a motorhome is a heavy truck, not a sports car. Don't expect sports car performance out of heavy truck.
So, started with the circumference of your planned tires -- in my case, LT235/85R16. Divide 63360 (inches in a mile) by tire circumference in inches. This yields tire revolutions per mile. Plug in vehicle speed (55-65 mph) to get rear wheel revolutions per minute (RPMs) at those speeds.
Use the rear wheel RPMs with the rear axle ratio to get the driveshaft RPMs.
Next, take into account the transmission's final (third, fourth, fifth, or what ever gear) ratio. Most older transmissions, such as the A727 automatic, have a 1:1 final ratio. Newer overdrive transmissions, such as the A518 automatic, have a different final ratio.
In the case of transmissions with a 1:1 final ratio (i.e., the A727 I plane to use), the driveshaft RPMs will match the engine RPMs. In the case of overdrive transmissions, the engine RPMs will be lower than the driveshaft RPMs. (If not, you screwed up your calculations.)
You now have the preferred 'sweet spot' around which you (or your engine builder) can plan the engine and select appropriate engine parts.
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StingrayL82
Nampa, Idaho
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I use this site and plug in the numbers
(1:1 on the transfer case, since it's a 4WD site): Final Drive RPM Calculator
2587 RPM @ 55MPH
2822 RPM @ 60MPH
Fred
Retired Army Guy
2005 Monaco LaPalma 37PST
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Griff in Fairbanks
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StingrayL82 wrote:I use this site and plug in the numbers
(1:1 on the transfer case, since it's a 4WD site): Final Drive RPM Calculator
2587 RPM @ 55MPH
2822 RPM @ 60MPH
Something's wrong 'cause I'm getting slightly different figures ... working them out myself.
Maybe you used LT235/75R16 instead of LT235/85R16. (Larger tire diameter and circumference means lower RPMs.)
Will post my figures in a few minutes ...
* This post was
edited 06/04/18 03:51pm by Griff in Fairbanks *
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Griff in Fairbanks
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Driveshaft RPMs should be greater than rear wheel RPMs. If not, you divided by the rear axle ratio rather than multiplying.
For example, LT235/85R16 tires have a circumference of 99.67 inches. (Slight variation is likely ... plus people doing the calculations for online sites aren't very good with millimeter to inches conversion and simple mathematics.)
63360 (inches per mile) divided by 99.67 (inches) is 635.7 revolutions per mile.
635.7 (rear wheel revolutions per mile) times 55 miles (at 55 mph) divided by 60 (minutes per hour) is 582.725 rear wheel RPMs. The same calculation at 65 mph is 688.675 rear wheel RPMs.
With a 4.10 rear axle ratio, driveshaft RPMs are 2389 RPMs at 55 mph and 2824 RPMs at 65 mph.
With a 4.56 rear axle ratio, driveshaft RPMs are 2657 RPMs at 55 mph and 3140 RPMs at 65 mph.
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