Ram Air Question: Fan Type
 

For 67 & up, what was the standard cooling fan that came with a Ram Air car?

- 4 blade steel fan

- 5 blade flex fan

Thanks!

I'll stick my neck out there and suggest the five blade;
As I have understood the four blade fixed unit was more for the bread and butter engines, but the five blade was put on all (non-A/C) 4bbl performance motors...

If nothing else, someone may chime in to correct me ;)

Should be 5 blade flex. 9798940

From what I have seen lately on concourse gold and original RA I and RA II cars is the steel 4 blade. I am doing more research on the topic, but it looks like the 68 RA cars use the 4 blade.

It would be interesting to learn what you find in your research. The factory literature shows the 5 blade fan. I wonder what fan is on the unrestored black convertible deuce.....anyone have any pics of the engine compartment with the correct view angle to see the fan? I think Jim Mino's car had the 5 blade fan....

I wouldn't be surprised if many owners swapped the 5 blade for a 4 blade shortly after delivery in hopes of free hp....especially in the cooler climates. Probably not a good idea in the desert Southwest though...:)

My '69 RA3 4-speed no-air GTO came with the 5-blade flex.

My survivor 68 ram air car has its original four blade fan.

REALLY!!

Now that is down right surprising!!

Here's a picture of the fan.

I think there is a strong case for the 4 blade fan on the 68 Ram Air cars. The dealer brochures make multiple references to the 5 blade flex fan (Power-Flex code 684) as standard equipment for GTOs.....but that doesn't prohibit the use of a different fan for the ram air engines.

The illustrated facts and features brochure shows photos of the family of available engines but the photo for the ram air engine is a close up of the air cleaner so the fan isn't visible in that photo so we can't draw any conclusions from that page.

Probably the smoking gun is the MPC book. It specifically lists 9798940 for the 67-68 F/8-T/8 400 Ram Air application. I originally assumed that part number is the 5 blade flex fan but if I flip to the previous page I see that same part number listed for multiple applications with the additional description as being a 4 blade fan (2 5/16" pitch).

When I bought my car it had a 4 blade fan but the engine had already been changed so I don't know if that fan was original or not. Based on the MPC book....the 4 blade fan is correct for Ram Air cars in 67-68. I hope I have it laying around still.....

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Good info. Thanks for posting. More ammunition for the 4 blade fan as correct for these cars.

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Did any application use the optional 7 blade flex fan as standard?

I don't think there ever was a factory seven blade flex fan;

As I have come to understand, this is how Pontiac V8 fans were:
- 4 blade fixed
- 5 blade flex
- 7 blade fixed; clutched

It is also worth noting that generally speaking the different fans used different spacers.

The four blade pictured above does have a spacer that I generally associate with the flex fans...

I am very glad that I posted here, because this has been a great discussion so far!

Yep, just checked the option, it says 7 blade fan and clutch HD. Option 514 .... same fan as standard with 582 AC.

There was a discussion about the 4 blade fan on FirstGenFirebird

https://firstgenfirebird.org/forums/...=228979&page=1

Also, here is a picture of the Aegean blue 68 RAII at the nationals in 2013 with the 4 blade fan

Attachment 466140

Disagree, have owned 2 of the factory 7 blade variable pitch, ie, flex fans. The factory 7 blade flex fan is just not something that is commonly run across.

4 blade......................19" diam 2 5/16" pitch #97xxxxx (later replacent is 9798940)

5 blade var pitch.........19" diam 2 5/16" pitch #9791346
(first use '67 models, a few made it onto '70 model GTO's before replaced by 480033)

7 blade var pitch.........19" diam 2 1/2" pitch #9796135 (HDC usage, have only found on big cars)

Not even going to get into all the different 7 blade different diam AC fans, too many styles.

Great reference photo. Same adapter style as shown in the photo of the RA I GTO posted earlier. Fantastic info and comes just in time for my build!

This is the fan I was curious about. Not sure which exact variant it was, but was shown in a spread of optional parts on a 68 GTO ... seen with various RA components in the foreground. Looks somewhat variable pitch to me ... but might be standard AC fan. Would appear from the hub that it's a clutch fan.

http://forums.maxperformanceinc.com/...1&d=1508909056

Correct, the 7 blade flex direct drive fans are a factory part with a part number. I believe they were more common in Chevrolet applications. I have about 5 or 6 of them here. I used to by them all the time and upgrade the cars with them for better cooling.....man those things move some serious air.
In the 1980's I used to run across them all the time at swap meets for $20-$30, I'd just snatch them up.
I don't use them as much anymore because they soak up some HP, lol I have one car here that is currently still running one. I switched all my other cars over to 7 blade clutch.
Dad's 69 GTO had the factory 5 blade flex, but he has also switched that car over to a 7 blade clutch.

Yep that's a 7 blade clutch fan.

So here is the data I have collected from many 1968 build sheets from the Pontiac plant. A few of the boxes they would put the last 2 or 3 digits of the part # in the box. Like the starter box, 53 stands for 1108353 Ram Air/HO starter, and 55 stands for 1108355 standard GTO starter. In the air cleaner box, 826 stands for 6424826, the STD GTO air cleaner. The SPACER/CLUTCH box next to the FAN box will have a 53 for 535253 std flex fan spacer, or PH for GTO with A/C fan clutch or PG for Lemans with A/C fan clutch. But the FAN box for GTO's I have seen AA code for A/C cars, BB code for non A/C cars. The one RA II car that I have a build sheet for (car #16 on the Ram Air Roll Car) has code 34 in the FAN box. That coincides with a Lemans with no A/C the 34 code with 53 spacer. I'll try to put it into a chart.

FAN CODE --SPACER/CLUTCH---ENGINE--- DESC.
AA-----------------PH--------------------- YS-------- GTO AUTO WITH A/C
BB-----------------53----------------------WT--------68 GTO 4-SPEED NO A/C
AA-----------------PG----------------------YN--------68 LEMANS AUTO WITH A/C
34------------------53----------------------YN--------68 LEMANS AUTO NO A/C
34------------------53----------------------WY-------68 RAM AIR II GTO

So AA and BB do not match up to the fan part#'s, so the AA/BB must just be a code like PH/PG.

The 34 code does not match up to the 4 blade fan (9798940) but it does not match to the 5 blade flex fan either (9791346). Is the 9798940 a new part number for a superseded number? The most convincing evidence I have for the 4 blade fan on the 68 RA cars is the build sheets of the RA II car and the 68 Lemans with no A/C. They both list the 34 code. I will post pictures of those two. If anybody else has any other 68 build sheets that would be helpful too.

Attachment 466160

Attachment 466161

Fantastic info. My MPC book is 1971 edition so the 9798940 part number might be an updated number. OPH indicated as such....perhaps he has the MPC book from 1968 and can look up the original part number. I will dig in my storage bldg this weekend and see if I can find my original fan....perhaps there will be a number on it somewhere.

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Wonder what the difference is between the AA w/PG clutch (lemans w/AC) and the AA w/PH clutch (GTO w/AC)?

I scavenged parts for my 68 YS GTO with AC, from a 68 350 Lemans with AC .. so while the fan is the same the clutch codes are different.

I would assume the clutch length would be exactly the same Lemans/GTO both with AC .... maybe one HD the other not? I'll be using a new Hayden clutch anyway.2

Good question.
Maybe one of the fan clutches locks up at a different temp than the other?

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I think the '34' is 1 more than the part #?

http://forums.maxperformanceinc.com/...1&d=1508970120

:confused:

I looked at my '70 Judge and the fan is a 7 blade clutch,..the engine is a Ram Air lll..,
all factory equipped,..with AC and a mess of factory options,..I should state that it is an automatic!!

I would expect the 69-70 RA III to follow the same fan application convention as the 68 HO since it's basically the same engine and can be ordered with A/C.

Next interesting question for me is what fan did the 69-70 RA IV have? My MPC book doesn't appear to make any distinction for RA III or IV. I wonder if the 4 blade fan was required with the 4.33 axle?

Here is car #3 on Ram Air II roll call build sheet. It also has the 34 FAN code and the 53 SPACER code. I'll add it to my chart

FAN CODE --SPACER/CLUTCH---ENGINE--- DESC.
AA-----------------PH--------------------- YS-------- 68 GTO AUTO WITH A/C
BB-----------------53----------------------WT--------68 GTO 4-SPEED NO A/C
AA-----------------PG----------------------YN--------68 LEMANS AUTO WITH A/C
34------------------53----------------------YN--------68 LEMANS AUTO NO A/C
34------------------53----------------------WY-------68 RAM AIR II GTO MAN
34------------------53----------------------XW-------68 RAM AIR II GTO AUTO

Attachment 466236

Yes, I think the GTO and the Lemans A/C cars used the same fan, for whatever reason they used different fan clutches.

I think by 69 the 4 blade fan was not used? I could be wrong. My brother's 69 RA III Judge with a WS engine has the original 5 blade flex fan. I think the 4 blade was a 67-68 thing? Another theory I have is that the wrong fans (5 blade) may have been put on some RA I and RA II car at the factory. The line workers would have been so used to non A/C GTO's that got the 5 blade flex fan that they mistakenly put the wrong fan on? I'm sure the pulley and fan selection was at the final assembly plant. The Ram Air cars would have been far and few between in 68. Just a thought.

Sounds reasonable that the fan designs we're improved and updated through the years since perhaps the 4 blade fan was phased out. I do see that part number in the MPC book for the 1969 V8 350 engine so that might have been the last use of that item.

Out of curiosity, I just looked at a build sheet for a 70 GTO with 455 and A/C. There isn't a box for fan but there is a box for fan clutch. Code on this particular car is "7J-PC". Looks like the fan and clutch codes we're combined by this time. Small detail but very interesting just the same. I suppose this means that by 1970 the fan spacer bin was removed from the engine dress line. If true....then by default the 5 blade flex as well as the 4 blade fans may have been discontinued around this time. By 1970....did all fans have a clutch?

On a totally unrelated topic....I find it interesting that the RPO code for A/C is "C60". Same code as my 2005 GTO.

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4 blade, 5 blade var pitch, & 7 blade clutch fans continued up through the '70's on Pontiac V8's. The HDC 7 blade var pitch fan was used up through at least '71 models on non AC B series. The 5 blade var pitch fan changed part numbers 3 times. The last time, in '73, the positioning of the blades was reconfigured. Many times, there will be characters trying to sell that latest version as a correct late '60's/early '70's performance GTO usage fan, it is not correct for that. Have several of the latter 5 blade fans, several that are dated for '73-74 usage & several that date for non AC w72 Birds.

Post after post, we keep seeing reference to MPC's. One thing I've learned & have documented on numerous parts is there were occasions of alternative components being used. Let's say an 06A body built Lordstown built RAII Bird was built with a 4 blade std steel fan. Does that mean every RAII equipped Bird that was built out of Lordstown, received that 4 blade steel fan? What about the other F-body plant, or the four '68 Pontiac A-body plants? On low production combinations, often if there is a question to whatis correct for a specific build, it is best to compare to other builds out of the same assembly plant, same time of the year. Only then, can one narrow down to the most likely used component.

Here's just one good example of a rare part that that one can't believe a MPC to know the parts original usage. I've owned 5 or 6 original date usage "1941" distributors...'69 RAIV right? Pulled each one of these distributors out of their original born with blocks. Had in my hands another as I pulled it from a customers numbers matching 30,000 mile original RA4 Judge during restoration. Also have owned two SR "1941"s in the box. Not a single one of these 1941's was stamped early enough to have come out of a '68 RAII engine, though am sure we can agree that early dated 1941's were used in the RAII engines.

Of these 7 original dated 1941's, 6 of them were never installed in a ' 69 RAIV engine. Their original factory installations were in performance Dport engines built 3-4 months before the first customer avail RAIV rolled out of an assembly plant.

Can name instance after instance of similar occurrences. it's real convenient to whip out MPC's or build sheets & state emphatically, this is how the car built. That is not always a fact.

Good points to remember. The literature gives us a good idea what was intended but that may not translate to reality in some cases.

The distributor that was in my very very early RA II is the same part number as the distributor used in the Ram Air I engines....according to the MPC book that I have. However, that really doesn't mean much since the engine was replaced before I got the car so it's anyone's guess if that distributor is original to the car. According to the literature....it's not correct. I will use it anyway. The next owner can worry about finding the 941 unit if it matters that much to them. Would have to be a very early date code or else it would be just as incorrect as the one I have now.

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OPH .... you should have meticulously recorded all your findings for posterity. Otherwise all this will be lost, like tears in rain (to quote Blade Runner )

After decades of boneyarding my experience is that as a rule the RA3 cars in 69 had the same fans as base engine GTO’s (5 blade flex with no AC or 7 blade clutch) with AC) but RA IV cars had the same 4 blade rigid fan you see on non AC lopo engines in LeMans or full-size etc.

Perhaps the rationale was that IV cars and earlier years RA cars all had digger gears that kept the fan running fast enough that they could get away with the smaller fan?

One thing I’ve noticed is the non AC base or RA3 cars I’ve run across over the years that had a factory ordered clutch fan (PHS or buildsheet) also had AC spec pulleys on the fan and crank.

I agree that there was an HD 7 blade flex option in69 (clear as day in the accessorizer) but never have I seen a car that was ordered with one or a pic of that fan.

Yeah the factories did odd things. I have 68 Lemans convertible parts car that I have had for 20 years. I always thought something was odd about the rear end. It had an odd part number that I hadn't seen before. After reading up on the nodular rear ends I put 2 and 2 together. The car was built at the Pontiac plant the last month of production (06C). They must have run out of the standard housings and they built a 2.56 WB code open nodular rear end! I recently parted another 68 Lemans that was built very late too (last week 07C) and it had a 69 9795082 rear end cast on G158, July 15 68. So a very very late 68 had very early 69 rear end!

In viewing nearly a dozen well preserved '69 RA4 GTO's including two every number matching low 30,000 mile Judges, one built in early April, another built out of Fremont, late in June, have yet to run across a 4 blade standard fan on any of them. All had 5 blade "346" variable pitch fans. The original '69 WW out of the early April build, I disassembled in '94, even the original starter was still there.

You’ve had more experience than me on IV’s I ran across only 2 or 3 in 30 years.

Other thing I notic d, both non AC 69 goats that I had buildsheet and PHS or window sticker that were ordered with the clutch fan option both had 3.23 gears and weren’t ordered with an axle option. Maybe the guy on the lioness saw the declutching fan and by habit dropped in a AC spec 3.23. Or it could have been intentional by the factory with that fan to limit the ratio?

I know that when I’ve tried clutch fans on 3.55 cars they run hotter than a flex fan on the highway but cooler in stop and go traffic

Absolutely , RAIV cars got 346 5 blade flex fan .

Not sure how I missed this before....
Here is a page from the GTO Restoration Guide book on this topic.

https://uploads.tapatalk-cdn.com/201...300fe3a125.jpg

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With regards to the assembly plant worker making a mistake or assumption or the plant running out of parts and using whatever they had on hand...

Sure, things were different 50+ years ago at the typical assembly plant compared to today but it's not like they were building cars in their garage.
There were build orders, Broadcast Sheets (or Bingo, Tracking Tell-All sheets) taped to the body, engine, etc. with instructions for the Operator.
When the car came into a station, the Operator didn't simply make a judgment call based on what they felt was right, they installed parts per instructions.
There were also inspectors and material control. If they ran out of screws, someone didn't just run out to the hardware store for more.

Today of course, there are still Broadcast Sheets taped to the body and driveline components but there are also...
Sequenced parts, barcoding, pick-lights, Work Station Monitors displaying specific parts for vehicle in-station, vision validation, etc.
Mistakes still happen with putting the wrong part on car but nothing like 50 years ago when you could have a friend upgrade your axle.

All this to say... If survivor or original, un-tampered with Ram Air cars from '68 have a 4-blade steel fan, it's safe to say that is the fan used on all others.
(unless of course an option called for a different fan).

Then again..... Never say never, right?

:)

Does anyone have a 4-blade, 19" dia., 2-5/16" pitch fan that they could share a pic of? I'm curious as to how/where the pitch is measured.

Thanks!

I looked at mine a short bit ago. Not sure how the pitch is measured but I think it's generally rise over run. If that is the case then the rise is about 1 9/16" divided by run of about 3 1/2" (width of fan blade). I believe the math works out to be 2.24 so that is just shy of 2 1/4". If my measurements are off by 1/16" then that could account for the variances from 2 1/4" to 2 5/16" I suppose...

https://uploads.tapatalk-cdn.com/201...cf7ba45682.jpg

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Parts catalog, Mar. 1969...

https://c1.staticflickr.com/5/4571/3...415dd78a_c.jpg

https://c1.staticflickr.com/5/4547/3...29b69150_c.jpg

Part # 519834 has a lot of usages. All are 19" diameter with only (1) application noting the pitch as 1-5/8". Where did 2-5/16" pitch come from?

Interesting...

In the Mar. 1971 Parts Catalog, the 519834 4-Blade Fan is no longer listed. Instead, there is a 9798940 4-Blade Fan that is 19" dia. with 2-5/16" pitch.
This Fan is listed as being applicable for Firebird & GTO Ram Air.

https://c1.staticflickr.com/5/4541/2...b2a5d4f9_c.jpg

So, apparently 9798940 superseded the 519834 Fan which would mean that factory Ram Air cars came with a 19" dia., 1-5/8" pitch Fan.

Thoughts?

Here is a 2-5/16" pitch 4-Blade Fan...

https://c1.staticflickr.com/5/4545/3...dfb11fe2_c.jpg

It is no wonder GM gave Pontiac the chop! Ridiculous number of fans with huge inventory costs when 4 fans would have covered the whole model range.

interesting;
That 9798940 fan is the same one I have from a 1973 Pontiac 350 - I suspect many of those have been thrown out over the years.

The original part # of 519834 makes perfect sense. The 68 RA build sheets show 34 as the fan code, the last two numbers of the original part #. They also show 53 as the spacer code, the last two numbers of the 535253 spacer. I figured the 9798940 superseded the 519834 number. RA1John, do you have any more pictures of your original fan?