E type engine frames. New option

FWIW, I just got off the phone with sng barratt after a discussion about engine frames. They now carry a frame from a different supplier from England as well as the Robey ones. The claim is that they are made of original material(531) and fit better and are stronger than the Robey ones. Price is approx 2000 per side vs 1200 for the Robey ones.

If it were my choice, and the fit was decent, Id damn sure not replace with the 531 frames.

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I wondered about that but the info from the salesperson was that the new company had done crash tests and the 531 frames performed better than the Robey non 531 frames. I wonder what the Robey material is and if they are in fact repairable by welding. Unfortunately with most of what you buy it is hard to know what to believe.

This is what it says on the SNGB web site for the new"uprated" $2000 frames:

“Exclusive to SNG Barratt. Manufactured using genuine Reynolds 631 steel alloy tubing, this is far stronger than the original 531 tubing that was used. Coated in quality Dupont reaction primer.”

So, they DO NOT use 531 tubing, but something they say is stronger… This seems to contradict what the SNGB Salesperson told you, so what are we supposed to believe? I wonder if these are E-Type Fabs frames at a bit of a discount from direct prices, because of the volume SNGB can hope to shift…?

From Reynolds web site:

Utilising the same chemistry as 853, Reynolds 631 is cold-worked and also has the advantages of air-hardening after welding. The alloy is a development on our famous 531 range with 10% higher strength. For cycling use, this provides tough, durable and comfortable frames particularly suitable for long distance riding, ATB and BMX . It has recently become available for touring and race fork blades.

It can also be used for sports car chassis, suspension units, motorcycle race frames etc. in welded and fillet-brazed structures. In most applications, it should not be necessary to stress-relieve the weld zone.

Why Reynolds 631 works:

UTS: 800-900 MPa, density 7.78 gm/cc.

As 853 in composition but tube strength results from the extensive cold-working of the seamless billet without a final heat-treatment. The TIG welded part of the tube still benefits from the air-hardening feature that results in a fine grain structure within the heat-affected zone.

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Could be but he did mention E type fabs and I understood that they no longer carried them. It makes sense that it would be 631 as it seems that 531 is pretty much obsolete. Did a quick search on 631 and it looks like it is both tig weldable and brazable with air cooling. Big bonus for future repairs.

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Oops. You got in the weldable part ahead of me John. Will have to learn to type faster.

:smiley:

I recall discussions years ago about “why don’t they make new frames from 531” and IIRC, the answer then was “some of the tubing sizes were no longer made”.

To my non technical, non metallurgist mind it looks like 631 would be a logical choice.

I guess that begs the question. What are the Robey frames made of and are they repairable? I think I will fire off an email and enquire.

Hello Geoff,
Robey Frames use T45 to which the following apply. Its similar to 4130 grade.

Welding:
The usual methods of welding are brazing and TIG welding. If MIG is used, stress-relieving processes may be needed.

Ultimate Tensile Strength:
700-900N/mm2 = 45/58 ton f/in2

Typical Mechanical Properties
Tensile Strength (ksi) - 80
Yield Point (ksi) - 70
Elongation (% in 2") - 15
Rockwell hardness RB80

Typical Chemical Analysis
C .15 - .25
Mn 0.30 - 0.60
P 0.040 max
S 0.050 max

Regards,

Bill

Thank you for that Bill. I wish I had looked into that earlier. I would not have been afraid to shorten and rebraze the too long leg on each of my frames then. It looks like the only non repairable frames are now just factory originals?

Originals can be repaired, just not fusion welded.

It was my understanding that the brazing technique was not really applicable to the average guy in his garage. Is that incorrect?

Hello Geoff,
Brazing has its required skill set, but it would be easier to learn, off the bat, than fusion welding. Accordingly, it would be more applicable to the average guy than fusion welding. The biggest issue with brazing is getting the parent metal too hot and burning the zinc in the filler rod.

Somewhere in Monocoque Metalwork’s website, Chuck makes reference to how good the brazing technique of the factory workers putting the original frames together was, due to all the practice they had over time. My observation is that the brazing of most of the original frames is fairly poor. My guys would be out the door if they did work like that.

Its also been stated, not by Chuck but elsewhere, that the frames were oven brazed. This is clearly not the case based purely on the appearance of the braze fillet.

Regards,

Bill

Oven brazing would be appropriate for frames made of lugs and tubes, like many old-school bicycle / motorcycle assemblies. The E-type frames have no lugs,

So then my takeaway is that the original tubes can be shop brazed by a competent welder with good heat control?

I was under the impression that Jaguar themselves maintained that original frames cannot be repaired. My experience has been that rebrazing cracked fillets caused the Reynolds alloy directly beside the repair to eventually crack, but that might have been a reflection of my brazing skills.

Reynolds says the critical temperature for brazing is somewhere around 1750 degrees F, IIRC. I always assumed Jaguar recommended the frames not be repaired was because the repairing shop or person might be unfamiliar with Reynolds tubing and would likely try to weld and overheat it.

That is my understanding: I was fairly adept at brazing, and never effectuated a good repair to the bike frames I attempted to repair. Mild steel, I could rock on.

When they say temperature is critical, they mean critical.

Lynx modified E-Type frames and my D is similarly ‘adjusted’. My D is only anecdotal and hasn’t turned a wheel in anger but Lynx made 80-100 (?) and had no problems AFAIK.