Mixing of hose clamp styles

[Geoff C.]

Gentlemen and the few Ladies present

What is the currently accepted opinion for

The transition date for Corbin heater hose clamps to Wittek tower style heater hose clamps?

Did the General mix these 2 clamps styles together on the heater hoses of the same Vette in any model year?

What was the last year that Wittek tower style radiator clamps were used?

Were the Wittek tower style radiator clamps ever mixed together with the side screw radiator Surtite Witteks on the same Vette in any model year?

Thank you,

Geoffrey Coenen

PS I know what most of the “professionals “ have to say in their catalogs. But, what do the C3 judges, amateurs, original owners and soothsayers have to say about them. Many thanks.

[Roy B.]

Re: Mixing of hose clamp styles

The first Corvette using both was the 1953 on various hoses

[Geoff C.]

Re: Mixing of hose clamp styles

Roy,
Please re-read the question.
This is not a multiple choice test.

Geoffrey

[Joe L.]

Re: Mixing of hose clamp styles

Geoffrey----

I have no information regarding the Corbin-style clamps. However, I can tell you that my 69 was originally delivered with both the Wittek tower clamps and the worm-style clamps. I don't recall the exact positions of each with respect to the heater and radiator hoses. However, I do recall, for sure, that the AIR hoses had a Wittek style tower clamp on one side and a worm-style on the other. The exact same 2 clamps are still on the hoses.

[Roy B.]

Re: Mixing of hose clamp styles Da???

Geoffrey Sorry your right! What is wrong with me??

[Paul B.]

Re: Mixing of hose clamp styles

Geoffery, the 1968 AIM shows a change from the "corbin" style to "tower" style reflecting March 19th, 1968. I remembered this date as it is the body build date of my "1968" coupe. The corbin style clamps probably were used until the supply was exhausted, but my '68 has the "original tower" clamps along with the "original" GM logo heater hoses, the ones with the "blue" logo, or was that the "white" GM logo ones???

[Chuck S.]

Re: Mixing of hose clamp styles

Hmmmm...That's a head scratcher, Paul. I think you are saying the change to tower heater hose clamps was implemented a day or so after the AIM sheet revision box was signed off.

I would figure that would be impossible considering that the approved AIM sheet master would have to be reproduced, copies distributed to all the inspectors/supervisors owning the AIM binders, parts ordered and received, and line workers provided with some minimal orientation on how the parts were to be installed. How could all that happen?

[John H.]

Re: Mixing of hose clamp styles

I spent many years of my life on the plant floor, and the A.I.M. sheets at each foreman's stand-up desk were maintained by a specs engineer from the Inspection Department office; he maintained the sheets that applied to that Foreman's production area (nobody had a full book except in the Inspection Office), and was present to assist when running changes were implemented on the line (last serial number of old parts, first serial number of new parts, old stock to be exhausted or scrapped, etc.), to record on the NPC (Notice of Production Change) paperwork for the plant files, a copy of which went to the releasing engineer at the Tech Center (none of which survive today). There was little rhyme or reason for timing of revised A.I.M. sheets relative to the production implementation of changes - the revised sheets could show up before or after the change was actually implemented. In the plant, the A.I.M. sheet was a secondary document, for reference only; what mattered to the plant was the NPC system, which drove changes in procurement and material scheduling, updated the Bill of Material, and drove the assembly and inspection processes. A.I.M. sheet change block revision dates were handled in the Chevrolet Engineering Drafting Graphics department, and are only a rough guide to estimating possible implementation dates.

[Paul B.]

Re: Chuck, No...

just maybe "around" that date. Like I said, they probably ran out the "corbin" style clamps.

[Chuck S.]

Re: Mixing of hose clamp styles

John, thanks for an interesting explanation of change implementation process.

I had gotten the impression from studying the AIM and associated changes in MY 70 that the production changes followed the AIM revision by 8-12 weeks. From your explanation, it sounds like the AIM revision isn't very helpful even as a rough guide on change dates.

One example of this process in 70 was the change from the UA6 Briggs & Stratton switch to the later version: using the estimated serial number change-over in the TIM&JG and the month-end production serial numbers, the math shows about two months from AIM approval to implemented change. There are other examples in 70, but none that I can remember being close to the AIM revision date.

If you're a blind man, you just have to keep feeling around and guessing what you're "studying" unless a sighted guy comes along. My education continues.

[Terry M.]

Re: Mixing of hose clamp styles

Chuck,
In my experience the classic extreme AIM-to-implementation duration example is the cotter pin to hold the rear toe shims, and the slotted shims. The hole in the frame and cotter pin shows up in the 1969 AIM (I can't read the date on my copy, and for this post it doesn't matter much). The slotted shims and cotter pin through the frame holes first show up, to the best of my knowledge, on 1970 model Corvettes built in the last week of that model year production. That has to be at least the entire six months of 1970 model production, and whatever 1969 production there was between the AIM revision date and the end of 1969 model production (mid-December 1969).
Did they have a car load of the two-hole shims laying around? Did it require some machinery modification? Did they have to retrain the suspension installers? I don't know, but it sure seems like a long lead time.

[Chuck S.]

Re: Mixing of hose clamp styles

Wow, never had the occasion to look at that one...The date on my Sheet A4 (UPC 4) is 10/14/69, which makes the delay over 9 months!!!

[Dick W.]

Re: Mixing of hose clamp styles

And then there were the AIM changes that never made it into production. John had the best explaination that I have heard. Heard a lot of suppositions, but this is coming from the proverbial" horses mouth"

[Terry M.]

Re: Mixing of hose clamp styles

Geoffrey,

I can only help with one item. The last year for Wittek tower style radiator hose clamps was 1969, and at that only part of the model year. At the end of 1969 production the Wittek "sure tite" side screw clamps were in use on radiator hoses. I have never seen a car that I was sure had not had some hose clamps changed with mixed radiator hose clamp styles, but I hasten to add that I have seen far from a statically significant number of 1969 Corvettes.