1969 427/390 A.I.R. System Pictures

[Gary H.]

Re: 1969 427/390 A.I.R. System Pictures

Pics of bowtie car.

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[Floyd B.]

Re: 1969 427/390 A.I.R. System Pictures

To muddy the waters further notice that in the first pic the clamp is not secured under the upper pivot bolt as shown in the AIM. I don't have a picture but Dobbins 2nd Edition, page 66, shows a small block engine with the clamp secured as illustrated in the AIM, J207, UPC 6, C2. However if you turn to page 79 and 80 of Dobbins you will see pictures of what can only be an L36 (i.e. BB w/ external fuel filter) and the clamp is not present as illustrated and noted in the AIM's L36 section, pg 365, UPC L36, Sheet A3.

The position of the fuel filter is different between SB and L36 cars. For SB cars the fuel filter is much higher so the clamp can be secured under the pivot bolt of the A.I.R. pump. In this case the fuel line from the filter to the carb is routed up and over the diverter valve. So the question seems to be: did the plant at some point figure out that the clamp could be secured under the A.I.R. pumps lower bracket bolt where it is secured to the block on L36's but the AIM was never updated to reflect this?

[Edward B.]

Re: 1969 427/390 A.I.R. System Pictures

Gary do you know the VIN of that car? Is it an early, mid, late??

Joe, correct. I just grabbed an extra pump I had in my garage and used it. I think the date is a 73 or 74? I don't remember. By the way, the pump has been gutted and is just for looks.

Yes, the 1969 L36 pictures in Dobbins book have no clamps, but who knows the status of those engines. Are they original? Not sure and he doesn't mention anything about it.

Ed

[Gary H.]

Re: 1969 427/390 A.I.R. System Pictures

I am 725757. I am not sure what his Vin was but it does not appear to be an early car as the photo doesn't show the vacuum tree on passenger side, but it also cuts it out if near the brake booster. Trying to remember the owners name si I can email him. Was a great car.

[Edward B.]

Re: 1969 427/390 A.I.R. System Pictures

Hmmm.... Well, we know the date in the AIM is correct since there are other entries after that with later dates, so I'd like to hear from other guys with original L36 engines to see what they have. It wouldn't be the first time the AIM was incorrect but I have a difficult time believing it took a year and a half for the change to go into effect. Especially since 1970 and later didn't use an external filter. Why make the change if they weren't going to enforce it???

Ed

[Floyd B.]

Re: 1969 427/390 A.I.R. System Pictures

Why make the change if they weren't going to enforce it???

Ed

I think we've seen some evidence (albeit, far from conclusive) that early '69s may have not had the clamp installed. But I think the difference between the AIM and production is explainable in this case. The position of the filter on L36's makes it impossible to secure the clamp to the A.I.R. pump pivot bolt as done on the base model. Perhaps shortly after production started for '69 it was realized that the clamp could be secured under the lower bracket support bolt where it attaches to the block - thus explaining the deviation from the AIM. Do we know the configuration of '68 L36's in this regard?

[Edward B.]

Re: 1969 427/390 A.I.R. System Pictures

While I agree the position of the filter would have dictated a change to the clamp attachment location, this would have been shown in the drawing. However, the AIM specifically states that the part was removed and the drawing revised to reflect this. If they wanted to note a change to the location, it would have stated something to that effect, not that it was removed.

Here are the two AIM pages. 1968 showing the clamp and 1969 showing the lack thereof. Yes, the filter location would have made it necessary to relocate the clamp position, but there's nothing in the 1969 AIM stating that the mounting point was changed, only that it was removed.

By the way, I've asked John (Hinckley) to comment on this since he's more familiar with the engineering procedures regarding the AIM, so maybe he can provide an explanation.

Ed

[Floyd B.]

Re: 1969 427/390 A.I.R. System Pictures

I think you may be missing my point. I'm suggesting the possibility that the change was made in production when they realized the alternative mounting location for the clamp so they added it back and the central design team was not notified so there was no update made to the AIM to reflect the change made my the production engineering team. Or another possibility is that the design team was notified (or even initiated the change) but they never went back and updated the diagram for any number of reasons - for example, they just simply forgot. The AIM is rif with examples of diagrams that differ from what actually occurred in production. The AIM only tells us what was intended, not what actually occurred.

[Edward B.]

Re: 1969 427/390 A.I.R. System Pictures

Again, I'll see what John has to say, but I don't think that scenario would be possible. Manufacturing wouldn't have the authority to make changes on the production line. It was all dictated by engineering via their testing and validation processes. All potential problems would have been sorted out by engineering long before the manufacturing side got involved.

Ed

[John H.]

Re: 1969 427/390 A.I.R. System Pictures

Again, I'll see what John has to say, but I don't think that scenario would be possible. Manufacturing wouldn't have the authority to make changes on the production line. It was all dictated by engineering via their testing and validation processes. All potential problems would have been sorted out by engineering long before the manufacturing side got involved.

Ed

Ed -

I'm not saying that this was always what occurred, but generally, it was. When a buildability issue arose on the line and a fix could be identified, the Resident Engineer (from CEC) was notified and became involved in developing a solution. If he agreed with the proposed fix, he called the responsible design/release engineer at CEC, reviewed the issue and solution with him, and got approval to make the change, authorized by a Local Deviation, which also involved the Material and Production Control folks to correct the inventory records. A copy of the approved Local Deviation went to the design/release engineer at CEC, whose job it was to write an ECR authorizing the change, and a copy of that ECR went to the Drafting Room to revise the affected A.I.M. sheets; this last step didn't always happen, especially if it was close to the end of the model year.

[Edward B.]

Re: 1969 427/390 A.I.R. System Pictures

Thanks John.

To add to this, the change in the AIM to remove the clamp is dated before the 1969 production started so by all rights, there shouldn't have been an an issue and the resident engineer wouldn't have to be involved. However, what has been found so far (and I admit there aren't a lot of data points), is that the clamp WAS used on the 1969 L36 (at least during the mid time frame) and affixed to the lower support bracket.

So as I see it, there are four possibilities:

1. The AIM is correct and the clamp wasn't used in production.
2. The AIM is wrong and that clamp WASN'T removed from production at all.
3. Engineering removed it but changed their minds and the clamp WAS used from the start of production, but the drawing was never updated in the AIM.
4. Sometime during the model year it was discovered that the clamp was necessary and was put back into production, but again, the AIM was never updated.

We know the AIM isn't foolproof and we've seen this type of error in other models and years. For instance, the 1968 Camaro AIM shows that the D33 Remote Mirror was cancelled in June of 1967 but in reality, it wasn't. We have too many original cars in the database with the option, so it appears to me that this is just another example of that type of error.

Since we don't have access to any of the ECR's, we'll probably never know the real answer, but I'd still like to have guys with original L36 cars chime in. Especially guys with early builds.

Ed

[Floyd B.]

Re: 1969 427/390 A.I.R. System Pictures

... but I'd still like to have guys with original L36 cars chime in. Especially guys with early builds.

Ed

Being the owner of an early '69 (4/10/68), I sure would like to have the answer to this mystery.