R600 vs R700 hood length

[Quickfarms]

How much longer is the R700 hood than the R600 hood?

[fjh]

Guessing at 6-8 inches!

[j hancock]

Here is a comparison of the truck dimensions between the R600 and R700 both utilizing the Mack CA 49 cab.  The difference is 12".

[Quickfarms]

I would like a real measurement of an R700 hood.

The pictures I have found are confusing, some make look like the difference is only 4", some look like 6" and some look really long unless there are different length hoods?

[JoeH]

Those are sweet dimensions. Do you have those drawings for a 1995 rd688s? 228" wheelbase? Does Canadian spread tandem have the same turning radius as the closer set American tandem with same wheelbase?

[keg1]

Looks like 12 in difference to me according to drawing

[Brian L Blaylock]

according to the dimensions in these drawings the difference is 12 inches according to the distance from front of hood to back of cab

[85snowdog]

I measured hood of my '86 RD688 and hood of '77 R795 .  I'm not sure if this helps of confuses the answer. 

The difference between mine is 10.5 inches . I will measure the hood of my R688 , but i'm pretty sure its the same as my RD.

 

[Vladislav]

Let me toss a handful of dirt a question in the ring - do you relate R600 and R700 Eastern R-model hoods? From what is written above looks like you do that. But I'm pretty sure the measurments of RS600 and RS/RL700 Western Valueliners would differ.

[Vladislav]

I found in my copybook a figure of 54-1/4 length of after '82 Eastern R-model hood. I remember I checked out the one on my R688ST of 1988 and it was to that size. So Keith's figure is the same dimintion, just with 1/4" difference due to the particular hood or the particular measuring band (I once got such issue with 2 different bends)

Also I see a figure of 53-3/8" for a pre-82 Eastern R hood. It was in series before the chassis mounted after cooler took place.

[j hancock]

On 12/30/2018 at 4:10 PM, JoeH said:

Those are sweet dimensions. Do you have those drawings for a 1995 rd688s? 228" wheelbase? Does Canadian spread tandem have the same turning radius as the closer set American tandem with same wheelbase?

I don't have a 1995.  The link is for a 2002 RD with a 210" wb. It is as close as I have.  The 2002 spec sheet doesn't list the turning radius.

All else being equal, I believe the US and Canadian spread would have the same turning radius because the 228" wb is at the center of the suspension for both examples.

https://www.bigmacktrucks.com/tutorials/article/214-2002-mack-rd600-dimensions/

 

[Quickfarms]

The blue 86 RD688 hood differs from my 85 RS688LST





My real goal is to find out how much longer a RS712LST hood is than my 85 RS688LST

I have been thinking about turning this truck



Into a close copy of this truck

[Quickfarms]

The blue 86 RD688 hood differs from my 85 RS688LST





My real goal is to find out how much longer a RS712LST hood is than my 85 RS688LST

I have been thinking about turning this truck



Into a close copy of this truck

[Vladislav]

10 hours ago, Quickfarms said:

The blue 86 RD688 hood differs from my 85 RS688LST



My real goal is to find out how much longer a RS712LST hood is than my 85 RS688LST

I have been thinking about turning this truck



Into a close copy of this truck

That's why I pointed out the difference knowing you have Western R which is almost a different story to East one along the hood, frame rails, front spring hangers etc.

Of possibilities to make RS700 of RS600 you can note the position of the front cab support brackets on these two pictures you posted. Looks like the spring hangers together with battery boxes and air tanks are positioned the same. But for the longer hood the cab is moved backwards. So the mounting points on RS700 are close to the rear edge of the battery box cover and RS600 has them near the front edge. To move the cab you would probably need those brackets themself (But they might be the same), move the rear cab support cross member, put new cab floor panel with a different hole for the shift lever, that lever as it's different, make the steering shaft longer (or different?) and so on. Probably could be done having a correct hood but not a one day work. And sure worth some extra investigation on a subject of purchasing a solid RS700 truck instead.

[Whiskymack]

On ‎1‎/‎1‎/‎2019 at 5:07 AM, Quickfarms said:

The blue 86 RD688 hood differs from my 85 RS688LST





My real goal is to find out how much longer a RS712LST hood is than my 85 RS688LST

I have been thinking about turning this truck



Into a close copy of this truck

I think these are the dimensions you want:

1977 RS700L  BBC=  117 inches        Bumper to front wheel centre= 28 inches 

1977 RS600L  BBC = 105 inches        Bumper to front wheel centre= 28 inches 

1985 RS600L Value-Liner  BBC = 106.75 inches      Bumper to front wheel centre= 29.75 inches 

The difference in 1970's models was a clear 12 inches but the introduction of the intercooler ahead of the radiator added an extra 1.75 inches to the front end of the RS 600L so the difference between your RS600L and an RS700L  should be 10.25 inches.

I've no experience of real tucks so can only speak theoretically. I have made reasonably accurate scale models of both the RS700L and RS600L. The front cab mounts for a 77 RS 700L and Value-liner look the same and also had one of the battery box mounts incorporated. On the RS700L the cab/battery box bracket was the rear support for the battery box but on the Value-liner it was swapped to become the front support. I don't know if the battery box/ cab support mounting holes for the front and back were in the same position on the frame and therefore interchangeable on both the 600 and 700 models but it might be worth looking into. Then there would still be the extra 1.75 inches at the front to consider as well as the other things Vlad listed.

 

spec sheet0001.pdf

[Vladislav]

Those 1.75 inches is an interesting point. That means you can't use RS700 hood combined with CMAC. At least without modifications.

Alastair, a pleasure to deal with your technical knowledges about Mack design. I too appreciate such approach in modelbuiding.

[Quickfarms]

Now to add to the confusion

 

The hood on my 1975 RS685LT and my 1985 RS688LST both measure 54.25" and the distance from the grill to back if can on both trucks is 105"

 

The 1975 hood is a flat top

 

The 1985 hood has the raised center

 

The 1985 RS688LST has the air to air after cooler mounted in front of the radiator

 

The 1975 was built in Hayward

 

The 1975 was built in Allentown

 

 

 

[Whiskymack]

On 1/5/2019 at 5:40 AM, Quickfarms said:

Now to add to the confusion

 

The hood on my 1975 RS685LT and my 1985 RS688LST both measure 54.25" and the distance from the grill to back if can on both trucks is 105"

 

The 1975 hood is a flat top

 

The 1985 hood has the raised center

 

The 1985 RS688LST has the air to air after cooler mounted in front of the radiator

 

The 1975 was built in Hayward

 

The 1975 was built in Allentown

 

 

 

That does add to the confusion!

But there may still be an explanation......

I think your last line was meant to be 'The 1985 was built in Allentown'.

This would make sense because I believe Hayward closed in the early 1980's and all production of Hayward models was transferred east.

The hood ridge appeared roughly about the time the RS600L got the Value-liner moniker but can also be found on some very late model RS700's.

I have also seen it on a few metal dash RS700's so I imagine that replacement hoods from about 1978 also had this ridge. I think the ridge may had served as a strengthening rib but I'm not sure.

As regards the fact that the hoods and BBC seem to be the same on both your trucks despite the spec sheet dimensions saying otherwise, this is my best guess:

On RS700's, pre Value-Liner RS600's and first Generation Super-Liners the back edge of the hood comes right up to the outer edge of the cowl and you often see paint/hood chips on older trucks. On later 1980's models there is often a gap between the back end of the hood and the outer edge of the cowl. I would say this gap is about an inch but I don't know if it is as much as 1.75. I always imagined this gap was to stop the hood and cowl bashing together on trucks with air ride cabs but maybe it killed two birds with one stone by moving the hood forward a bit to make space for the rad mounted intercooler. Just a guess though.

You could try measuring from the bumper to the back of the cab as I think hoods tend to move around a bit as well. 

 

 

[dogg rescue]

I have a '78 rs712 long frame with neway air ride if your interested Quickfarms.

[Quickfarms]

I have a '78 rs712 long frame with neway air ride if your interested Quickfarms.

Where is it located and what are the specs and how about some pictures

[dogg rescue]

It measures 246" from center of the front axle to the center of the back axle. It has been stretched 25" and could easily be put back to the original length. It is a single frame except where it was gloved in the rear. The thickness is a 1/4", has round housings with no carriers. I would like to keep the fuel tanks. Asking 1200.00 located in Wheatland Nd. 701-730-4577 Mark

[Quickfarms]

It measures 246" from center of the front axle to the center of the back axle. It has been stretched 25" and could easily be put back to the original length. It is a single frame except where it was gloved in the rear. The thickness is a 1/4", has round housings with no carriers. I would like to keep the fuel tanks. Asking 1200.00 located in Wheatland Nd. 701-730-4577 Mark

Thanks for the offer but it would be a little hard to get to my place in Southern California and it is a bit more of a project than I currently have the time for.

[Nascarroush]

That’s an interesting read . How come some Mack Rs sit higher , is it the air ride or the fact that the Western hood as an extra 4” in height which is visible above the fenders. I’m guessing some had 24.5 wheels which would increase.I see some pics of the R Models where the hight of the hood is say 70” from the ground and others that look more like 80” . Always wondered what made the difference.

[mnslim]

On 12/31/2018 at 11:08 PM, Quickfarms said:

The blue 86 RD688 hood differs from my 85 RS688LST





My real goal is to find out how much longer a RS712LST hood is than my 85 RS688LST

I have been thinking about turning this truck



Into a close copy of this truck

Quickfarms:

Anything come of your plan to build an R700 from the white RS600?

The 600 pictured seemed like a clean truck. 

 

Nick

 

[doubleclutchinweasel]

https://www.4statetrucks.com/exterior/semi-truck-jones-performance-fiberglass-hood-mack-r-model_14502.asp?gclid=EAIaIQobChMIyNDyyeqo7gIVE_zjBx04vwWhEAQYBCABEgK2tfD_BwE

 

Mentions that this hood will fit '82 and older if 1" is cut off the back.

 

https://bigtruckhoods.com/collections/r600/products/mack-r600-new-non-oem-hood

 

This one says '82 and later.  I know there were 2 different R600 hood lengths.  Have heard it is 1" different, 1.5" different, and 2" different!

 

Both of these "new" models say 54-1/4" long.