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Hey hey boys, long time, and rebuilding another BN7.. This time, im stuck. I found some frame damage, not rust, on this BN7 and want your opinion on if I should repair or replace this frame... Its looks solid, no rot that I have seen, but, it does have a frame repair that has me a little worried. You can see the outline at min 2:35 of the video. Can you boys please take a peak at this video i did of the frame and let me know what you would do.. My goal is to be safe and drive "spirited"...
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BN7 - To Replace or Not Replace the Frame, That is the Question
- Thread starter kkaa
- Start date
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You will get lots of opinions on this question. I have a Jule frame on my car.
1. The extra supports for the engine mounts are very common. Yours were done a little crude.
2. The front cross member opening up is not that unusual, you can replace that cross member, not hard, you need to build a metal clamp that grabs the shock towers to hold the frame together while you chop the old one out.
3. The bent front section that holds the front of the shroud can be replaced also.
I guess that the rest of the frame might need blasting to get to bare metal and see if any holes show up. Outriggers are usually the best sign of severe rust.
tough decision, I replaced mine which was in worst shape in the engine area. I knew that I would keep the car. I have owned it for 18 years now.
Jerry
1. The extra supports for the engine mounts are very common. Yours were done a little crude.
2. The front cross member opening up is not that unusual, you can replace that cross member, not hard, you need to build a metal clamp that grabs the shock towers to hold the frame together while you chop the old one out.
3. The bent front section that holds the front of the shroud can be replaced also.
I guess that the rest of the frame might need blasting to get to bare metal and see if any holes show up. Outriggers are usually the best sign of severe rust.
tough decision, I replaced mine which was in worst shape in the engine area. I knew that I would keep the car. I have owned it for 18 years now.
Jerry
red57
Jedi Knight
Online
No way I would replace the whole frame on this one. You may want to replace the front frame legs but I would do a lot more assessing before plunging in - a lot of the problems are small and may be fixed with small, localized repairs sections.
Start by setting the frame up in a way that you can actually measure how flat it is - the bottom tapers upward towards the ends so you need to check the top surface.
If the main frame rails are not straight (appears the right front is curled upwards slightly) you will need to try to find the exact bend point. You may need to cut the scuttle braces loose from the frame so you can draw it back down in the front and then re-attach the scuttle braces.
I wouldn't worry about the bent sheet metal in the footwells/scuttle that you show - these were commonly bashed to fit in the factory, I have found a lot of serious hammer marks all over the whole bulkhead structures.
The front cross member damage is very typical from jacking damage and fairly simple to replace (Kilmartin makes a stronger replacement that can be used as a jack point).
The braces on the motor mounts are a very common upgrade, especially for race and rally cars as these are prone to cracking from the stress of that heavy motor - not necessarily a sign of accident damage. After you get it blasted clean go over these and the suspension mounting points carefully to find and repair any cracks (there probably will be a few).
Start by setting the frame up in a way that you can actually measure how flat it is - the bottom tapers upward towards the ends so you need to check the top surface.
If the main frame rails are not straight (appears the right front is curled upwards slightly) you will need to try to find the exact bend point. You may need to cut the scuttle braces loose from the frame so you can draw it back down in the front and then re-attach the scuttle braces.
I wouldn't worry about the bent sheet metal in the footwells/scuttle that you show - these were commonly bashed to fit in the factory, I have found a lot of serious hammer marks all over the whole bulkhead structures.
The front cross member damage is very typical from jacking damage and fairly simple to replace (Kilmartin makes a stronger replacement that can be used as a jack point).
The braces on the motor mounts are a very common upgrade, especially for race and rally cars as these are prone to cracking from the stress of that heavy motor - not necessarily a sign of accident damage. After you get it blasted clean go over these and the suspension mounting points carefully to find and repair any cracks (there probably will be a few).
Thanks for the reply red! Are you thinking of the bottom frame repair option? For the cost, thinking if im going into doing that, few more bucks get the whole frame?
If I were to go new on a frame, who would you recommend, and thank you boys!
Welch - > 3000 Chassis | Performance Parts | Austin Healey| Denis Welch Motorsport <
AH Spares - > Austin Healey BN4 & Early BJ8 Complete Chassis Frame <
Jule - https://jule-enterprises.com/prices
Welch - > 3000 Chassis | Performance Parts | Austin Healey| Denis Welch Motorsport <
AH Spares - > Austin Healey BN4 & Early BJ8 Complete Chassis Frame <
Jule - https://jule-enterprises.com/prices
red57
Jedi Knight
Online
Actually I was thinking of just the forward frame leg you need and the crossmember. (example from BCS website: Frame leg)
I suggest Kilmartin Automotive Sheet Metal in Australia - Kilmartin
They are closing down by the end of the year but you may still be able to get what you need
The US distributor is British Car Specialists in Stockton, CA - BCS
They have an extensive on-line catalogue of Kilmartin parts and are a stocking distributor. The also know the cars very well and are a great support for us all.
Kilmartin parts are by far the best fitting/ highest quality replacement sheet metal parts available (no financial interest). You might want to go thru the whole catalogue and get all the bits you know you will need now before they close down....
I suggest Kilmartin Automotive Sheet Metal in Australia - Kilmartin
They are closing down by the end of the year but you may still be able to get what you need
The US distributor is British Car Specialists in Stockton, CA - BCS
They have an extensive on-line catalogue of Kilmartin parts and are a stocking distributor. The also know the cars very well and are a great support for us all.
Kilmartin parts are by far the best fitting/ highest quality replacement sheet metal parts available (no financial interest). You might want to go thru the whole catalogue and get all the bits you know you will need now before they close down....
WHT
Jedi Hopeful
Offline
Hi kkaa,
If you intend to drive this car safely (or sell it to someone else after restoration) please do yourself a favor and replace the frame. Especially, with new 2mm thick frames available from AHSpares; and if you act quickly Kilmartin (both are excellent). Your frame has experienced considerable damage and has been poorly repaired.
Healey frames used thin metal in the frame and inner panels (1/16-inch) and the frames will be further compromised by what looks like minor rust. The steel thickness used in these frames was below recommended structural standards even when new. Please remember you will (i) most likely also find inner frame rust since the C-section frame tube welding experiences shear when the tubes flex letting in moisture and (ii) the repaired bending/rupturing in the frame that you see will further weaken its metal.
So, build a strong car that you can enjoy safely for many years if you want to drive it in a spirited manner.
Good luck with your restoration!
Regards, Bill
"The steel used in Austin-Healey frames has a yield strength of approximately 45,000 PSI and the ultimate tensile strength is approximately 50,000 PSI. These values indicate that the original safety factor to prevent yielding of the frame is about 5.9. A minimum static safety factor of 6 was typically used in frame design at that time.
Review of current American Institute of Steel Construction (AISC) and American Welding Society (AWS) codes suggest, however, that the static safety factor may not be this high due to the C-section welded frame construction. For box tubing of the 3 x 4 inch size, the AWS code specifies a minimum wall thickness of 0.109 inches (not 0.072 inches as in the Healey frame). The AISC minimum wall thickness per code is 0.085 inch. The AISC code is probably the more accurate of the two, as it was significantly overhauled in 1961 to better account for buckling of thin walled tubing. Note, this was 10 years after the Big Healey was designed. This means that the 5.9 static safety factor for the original frames may not be achievable due to compressive buckling of the tube at lower stress.
As a side note, if the longitudinal edge weld of the C-section frame is cracked or split, the continuous circumferential tube "hoop" is then broken, and from an engineering perspective the torsional resistance of the tube is reduced to less than 1% of its original torsional resistance at that location. This important engineering consideration is why racing cars are designed using cylindrical or box tube as opposed to C-channel or I-Beam for frames."
If you intend to drive this car safely (or sell it to someone else after restoration) please do yourself a favor and replace the frame. Especially, with new 2mm thick frames available from AHSpares; and if you act quickly Kilmartin (both are excellent). Your frame has experienced considerable damage and has been poorly repaired.
Healey frames used thin metal in the frame and inner panels (1/16-inch) and the frames will be further compromised by what looks like minor rust. The steel thickness used in these frames was below recommended structural standards even when new. Please remember you will (i) most likely also find inner frame rust since the C-section frame tube welding experiences shear when the tubes flex letting in moisture and (ii) the repaired bending/rupturing in the frame that you see will further weaken its metal.
So, build a strong car that you can enjoy safely for many years if you want to drive it in a spirited manner.
Good luck with your restoration!
Regards, Bill
"The steel used in Austin-Healey frames has a yield strength of approximately 45,000 PSI and the ultimate tensile strength is approximately 50,000 PSI. These values indicate that the original safety factor to prevent yielding of the frame is about 5.9. A minimum static safety factor of 6 was typically used in frame design at that time.
Review of current American Institute of Steel Construction (AISC) and American Welding Society (AWS) codes suggest, however, that the static safety factor may not be this high due to the C-section welded frame construction. For box tubing of the 3 x 4 inch size, the AWS code specifies a minimum wall thickness of 0.109 inches (not 0.072 inches as in the Healey frame). The AISC minimum wall thickness per code is 0.085 inch. The AISC code is probably the more accurate of the two, as it was significantly overhauled in 1961 to better account for buckling of thin walled tubing. Note, this was 10 years after the Big Healey was designed. This means that the 5.9 static safety factor for the original frames may not be achievable due to compressive buckling of the tube at lower stress.
As a side note, if the longitudinal edge weld of the C-section frame is cracked or split, the continuous circumferential tube "hoop" is then broken, and from an engineering perspective the torsional resistance of the tube is reduced to less than 1% of its original torsional resistance at that location. This important engineering consideration is why racing cars are designed using cylindrical or box tube as opposed to C-channel or I-Beam for frames."
Last edited:
For Jule, did you
Do you have someone at Jule you worked with?
WHT
Jedi Hopeful
Offline
Hi kkaa,
Call or email Joel Jansen at Jule. Joel is Martin's son and he will be glad to help you.
We have a Jule frame in our car and it much stronger than the original frame (it uses 0.125-inch extruded frame members).
juleframes@gmail.com
Regards, Bill
Call or email Joel Jansen at Jule. Joel is Martin's son and he will be glad to help you.
We have a Jule frame in our car and it much stronger than the original frame (it uses 0.125-inch extruded frame members).
juleframes@gmail.com
Regards, Bill