Bonnet Frame - Which weight of Chopped Strand Mat to use?
Discussion
I can't reccomend a material spec., however I can share a procedure tip. When removing the old (I asume bent or rusted)frame only cut away the top portion of the glass wrap over leaving a open "channel" to locare the new part. Then you only need to re glass the top area that you cut away to remove the damaged component. If you remove all evidence of the original location it will be almost impossible to install the new hoop in the proper location. G.K.
I beg to differ with Noah's advice. Remove ALL the previous material an start from a bare area. The old reference point may cause difficulties in aligning the bonnet properly if the new frame is not EXACTLY identical to the orignal. 1 mm out at the front of the bonnet can be 10 cm out at the rear of the bonnet.
Remove all old frame and previous matting matting. Mount new frame onto chassis centrally in adjustment slots. Attatch bonnet into bonnet locking catches at rear of bonnet and using axle stands, strips of wood etc adjust position of bonnet to acheive best shut lines and alignment. Crawl under front of car and adjust bonnet frame to give best fit to undersde of bonnet. Using ONE layer of matting bond the frame into place. Use a weak mix of resin and hardner and allow it to cure slowly, preferably overnight. Remove whole assembly from car and add two or three more layers of matting and allow to cure slowly.
Do NOT use a strong resin mix as this can generate a LOT of heat and damage paint on bonnet. This stuff gets VERY not when curing and the more hardner the hotter it gets and the quicker it sets. Wear protective gloves, its a pig to get the stuff off your skin. sTeVeR
Remove all old frame and previous matting matting. Mount new frame onto chassis centrally in adjustment slots. Attatch bonnet into bonnet locking catches at rear of bonnet and using axle stands, strips of wood etc adjust position of bonnet to acheive best shut lines and alignment. Crawl under front of car and adjust bonnet frame to give best fit to undersde of bonnet. Using ONE layer of matting bond the frame into place. Use a weak mix of resin and hardner and allow it to cure slowly, preferably overnight. Remove whole assembly from car and add two or three more layers of matting and allow to cure slowly.
Do NOT use a strong resin mix as this can generate a LOT of heat and damage paint on bonnet. This stuff gets VERY not when curing and the more hardner the hotter it gets and the quicker it sets. Wear protective gloves, its a pig to get the stuff off your skin. sTeVeR
I beg to beg to differ....do make sure that there is no trace of the old unit but then using fibrefill bed the leading edges (centrally between the bumpers) with this and ty-rap the cross member onto the chassis by drilling each side of the tube and putting them through wait for the fibrefill to dry, remove the scuttle spring pins from the bonnet and do a test fit FIRST before using any matting, ensure the frame is correctly aligned so that you can adjust up/down/right/left and the bonnet closes correctly, work out all this before you go any further if it's OK mat into place.
Adrian (he... who must of fitted TOOOOOO many in his life time)
Adrian (he... who must of fitted TOOOOOO many in his life time)
Pietro, with the bonnet off, you make like to add (if not already), a strengthening to the bonnet catch area. My 3000S came with one side adapted (you can see why!).
I've since repaired the broken GRP and made a similar part up for the other side .. however, I'd recommend that you ensure there is also 'broad' adjustment for the bonnet catch, as I've found that (but I'm no expert) that the distance between the catch and the firewall (ie. latch) also affects the bonnet fit (ie.gap). I've spent plenty
of time getting the bonnet adjusted to sit correctly, only to re-fit the catches and find that it seems no better than when I started 
I've since repaired the broken GRP and made a similar part up for the other side .. however, I'd recommend that you ensure there is also 'broad' adjustment for the bonnet catch, as I've found that (but I'm no expert) that the distance between the catch and the firewall (ie. latch) also affects the bonnet fit (ie.gap). I've spent plenty
of time getting the bonnet adjusted to sit correctly, only to re-fit the catches and find that it seems no better than when I started Now to get to the root of the problem ....The thinking seems to be that the spring pins and latching system at the scuttle points hold the bonnet closed ....OK they do BUT then they do not, they are height adjusters to the exterior scuttle area, the bonnet has to fit the car FIRST, this is why we see so many cars with stress cracks around the headlamps with people lifting the front noses of cars to force the pins into the catches....The spreader bar across the bonnet has to be in the right place 2 inches from the leading edge of the bonnet so that the pins can be set into the spreader bar and enable the pins to be anywhere near the latches, if this is not the case (as in many replacement bonnets) the bar should removed from the bonnet and a new one set in it's place (the bar also sets the curvature/shape and width of the bonnet across the car, also a fault of replacement bonnets). The spreader already has 2 metal plates that support the pins, when the bonnet frame is fitted correctly these have no loads or stress that would warrant strengthening.
Having fitted FAR Toooo many bonnet's, bonnet frames and got one to do Tuesday!
>> Edited by adrian@ on Sunday 30th April 10:55
>> Edited by adrian@ on Sunday 30th April 16:14
Having fitted FAR Toooo many bonnet's, bonnet frames and got one to do Tuesday!
>> Edited by adrian@ on Sunday 30th April 10:55
>> Edited by adrian@ on Sunday 30th April 16:14
Tks Adrian .. as I said, I'm no expert ! As you mention, I do need to lift the bonnet at the front to close it ... always have done .. probably the result of not changing/re-fitting the bonnet frame when the chassis was replaced, before my time. However, you've motivated me to have another go. I assume when one hits the sweet spot, the bonnet balance naturally closes.
Is it best to start with the height adjuster (hindge end) in (low) or out (high) ?
Is it best to start with the height adjuster (hindge end) in (low) or out (high) ?
I would always remove the pins at the scuttle end of the bonnet, remove all the hinge points and mount the bonnet on the car using tank tape on all surfacing to avoid damage using a jack and plank of wood to set the correct height at the front and packers down each wing, then add the hinge eyelets into the frame setting them in line with the chassis slots, offering 3 inch 3/8 unf set bolts through the bush and into the slot on the chassis, using a lock nut and nyloc nut and 2 washers lock these bolts onto the chassis, (if you have and aftermarket bonnet then you might find that the drivers wheel arch will bow above the wheel and is impossible to get to look right, but heyho that's a TVR for you NOT!) With the front hinge point set the bonnet should open and close , now workout the amount of packing washers needed on the internal spaces between the bush and the locking nuts that you have locked on the chassis, find the correct 3/8 bolt with a shank to suit the bush and refit the bolts with packing washers and one washer to support the end of the bush on the external side leaving the hinges bushes packed out to stop R/L movement BUT free to rotate. Having set the bonnet F/R and R/L ensure the bonnet closes and mark the scuttle with a marker directly in-line with the latch holes and the leading edge of the bonnet so that the pins are fitted in-line of the marks using the 2 1/4 UNF bolt in the spring pin bracket to move these R/L add the pins and offer the bonnet closed, if you need to then reset F/R (on later cars set the pull cable up correctly tensioned using the opposite sides tensioner spring so that when pulled they open the spring pulls both closed) colse the bonnet and set the up/down height to the scuttle using the lock nut on the inside of the pin. If the pins forces the bonnet nearer or further away check the bonnet spreader is mounted correctly and replace if needed.
Adrian
>> Edited by adrian@ on Sunday 30th April 16:18
Adrian
>> Edited by adrian@ on Sunday 30th April 16:18
Duncscz - thanks for the advice - however I've already had a new spreader bar fitted by Adrian, after someone sat on my bonnet and cracked the spreader bar down at Le Mans. I know that the bar would have been fitted perfectly!
Adrian - your advice, as always, is invaluable.
Pietro
>> Edited by sprintmp on Tuesday 2nd May 08:27
Adrian - your advice, as always, is invaluable.
Pietro
>> Edited by sprintmp on Tuesday 2nd May 08:27
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