74' Hose ClampType at Heater Core

[Robert S.]

I know the heater hose clamps on the engine side are Whitig types. Question is what did the factory use at the heater core end - the spiral band type of clamp? That is what is on the car but I do not know if it is original but due to the tight space to work I would think the factory probably did use the spiral band type.
Can anyone confirm what type the factory used on heater hoses on a 74' at the heater core end?

[Jack H.]

Re: 74' Hose ClampType at Heater Core

This shouldn't be a mystery... Section 18, Mechanical, of your copy of the '73-74 NCRS Judging Guide book tells judges exactly what to look for...Wittek tower clamps.

[Harmon C.]

Re: 74' Hose ClampType at Heater Core

Their is one answer to this in the judging manual but as I see it applies more to cars without air conditioning. The two clamps on original air conditioned cars that I have seen are usally the band type but they may have been tower. It would be hard to install tower clamps in that locations limited space if the factory did use them. The location of the clamps makes them hard to install with the car on jack stands so judges may not be able to get a mirror or any other way to even see them. Someone may have checked this out on Bowtie cars with original hoses and will respond.

[Robert S.]

Re: 74' Hose ClampType at Heater Core

I read the judging guide and it suggests the use of band clamps at all 4 heater hose locations or you can read it as band clamps at the locations one easily see when judgeing - those on the engine and firewall on non-AC cars.
My son and I both have AC 74's. Neither of us is an original owner. Both of ours have spiral screw clamps at the heater core connections. His heater hoses are clearly not original so who knows how it came from the factory. I removed from my car (it has 32000 miles which I think is correct) what I think were the original hoses. Mine had the spiral screw clamps on the heater core.

Any comments from those with known original configured parts?

[Alan S.]

Re: 74' Hose ClampType at Heater Core

Hi Robert,
On my 71 I know the heater hoses are original and I could tell the type of clamp used and even how it was turned by the impression the clamp left in the hose. Each type of clamp seems to leave a distinct footprint.
Maybe you'll be lucky too! Have you looked for that clue?
Regards,
Alan

[Robert S.]

Re: 74' Hose ClampType at Heater Core

The hoses on my 32000 mile 74' with what I think are original hoses (as they have the small ribs along their length) have hose clamp witness marks that say that the two clamps on the engine end were band clamps and the two at the heater core end were spiral screw clamps.
My original question is whether that was what was used at the factory? As previously discussed the judging guide is a little ambiguous in my opinion.

Can anyone comment as to OEM clamps used on an AC C3 car?

[Harmon C.]

Re: 74' Hose ClampType at Heater Core

I read the judging guide and it suggests the use of band clamps at all 4 heater hose locations or you can read it as band clamps at the locations one easily see when judgeing - those on the engine and firewall on non-AC cars.
My son and I both have AC 74's. Neither of us is an original owner. Both of ours have spiral screw clamps at the heater core connections. His heater hoses are clearly not original so who knows how it came from the factory. I removed from my car (it has 32000 miles which I think is correct) what I think were the original hoses. Mine had the spiral screw clamps on the heater core.

Any comments from those with known original configured parts?

My 73-74 TIG&JM says tower clamps only. What edition says band clamps? In looking at the 4th edtion 70-72 TIG&JM it is interesting that some 454's with A/C use band clamps at the heater core. I'm not sure why a 454 would have less room for clamps between the heater box and the firewall but maybe someone can explain this. If both style clamps were at the work station at the factory I would bet the assembly line worker used what made his job easier.

[Ralph S.]

Re: 74' Hose ClampType at Heater Core

I am the original owner of a 73 with A/C The heater core hose ends have spiral clamps and the engine ends have tower clamps.

[Harmon C.]

Re: 74' Hose ClampType at Heater Core

I am the original owner of a 73 with A/C The heater core hose ends have spiral clamps and the engine ends have tower clamps.

I agrre with both you and Robert that A/C cars had tower clamps on the engine and sprial clamps on the heater on A/C cars in 73-74 MY. On non A/C cars all four clamps are tower style and are easy to judge.

[Robert S.]

Re: 74' Hose ClampType at Heater Core

Thanks to all for the replies. The reason for the original question is that I am going to replace the heater core this fall and wanted to use the right clamp type at reassembly. I think this is an example where the judging guide should be updated and clarified.

[Terry M.]

Re: 74' Hose ClampType at Heater Core

I know the heater hose clamps on the engine side are Whitig types. Question is what did the factory use at the heater core end - the spiral band type of clamp? That is what is on the car but I do not know if it is original but due to the tight space to work I would think the factory probably did use the spiral band type.
Can anyone confirm what type the factory used on heater hoses on a 74' at the heater core end?

I am a little confused here. I know what tower clamps are, but I see you refer to spiral band clamps. Some of the other posters refer to spiral and band clamps as if they were different types. What are spiral and/or band clamps?

As an aside -- Wittek made the tower clamp, and the worm gear hose clamp (SAE type F) well as other types of clamps not used on Corvettes. The Sure-Tite clamps used on the Corvette radiator hoses can be found on other brands of cars. ALL the clamps used on early C3 Corvettes were made by Wittek, so I am certain whatever style of clamp was used on the heater hoses, it was certainly a Wittek clamp, however describing it as a Wittek style leaves a lot to be desired.

I suggest an update of this post is in order because I may not be the only one who is not sure what clamps are being described.

[Harmon C.]

Re: 74' Hose ClampType at Heater Core

Hi Terry
I went along with the first posters description my error. The clamps I have seen on A/C cars at the heater core were Wittek worm gear hose clamps.

Good Point Terry

[Terry M.]

Re: 74' Hose ClampType at Heater Core

No error Lyle, I'm just having a hard time following where this is going -- and I want to keep up on this because 1970-72 is likely the same. I have seen a few reasonably original AC 1970-72s with the worm type clamps at the heater core -- not enough to make a decision on, but enough that I wouldn't make a deduction for them.



I wish I could remember where I got this, but someone once told me on AC equipped C3s the heater hoses were attached to the heater core, and then fed through the heater box openings from inside the car. The result is that the clamps (whatever type they are) can be in an inaccessible location once the car is assembled. I am skeptical that the clamps will clear the openings -- but it is something to consider.

[Robert S.]

Re: 74' Hose ClampType at Heater Core

I aplogoize to everyone as I can see that I should have been more careful in the terms I used to describe the clamps as I can see how I caused some confusion from post to post. At this point I think my experience and those of others, especially the one responder who had an OEM configured 73' is that the AC 73/74 cars came from the factory with Wittig tower clamps at the engine side (of two different sizes as correctly described in the 73/74 judging manual) and at the heater core side the clamps were Whittig spiral screw type clamps of sizes unknown (this last point is not described in the 73/74 judging manual and in fact the judging manual would have one believe the heater core end clamps were Whittig tower clamps).

[Harmon C.]

Re: 74' Hose ClampType at Heater Core

No error Lyle, I'm just having a hard time following where this is going -- and I want to keep up on this because 1970-72 is likely the same. I have seen a few reasonably original AC 1970-72s with the worm type clamps at the heater core -- not enough to make a decision on, but enough that I wouldn't make a deduction for them.



I wish I could remember where I got this, but someone once told me on AC equipped C3s the heater hoses were attached to the heater core, and then fed through the heater box openings from inside the car. The result is that the clamps (whatever type they are) can be in an inaccessible location once the car is assembled. I am skeptical that the clamps will clear the openings -- but it is something to consider.

I agree Terry that I have never taken a deduction on A/C cars for clamps at the heater core. First I never tried to see them as I know how hard it is to get at them to get the clamps off or on. I thought either type could be correct. I will try to see the clamps with the car on the ground just for fun.