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View Full Version : TR4/4A TR4A bonnet dimensions needed



Steve P.
09-18-2004, 12:33 PM
I spent part of this past week putting my recently purchased basket case TR4A back together. For the most part things look good, until I put the bonnet on. There are large gaps between the bonnet and fenders, but only at the front. Its obvious that this car had been hit in the front, lightly, at some point (bondo), but I don't know if the bonnet or the fenders (or both!) are bent. If there is someone out there with a straight, original car, I'd like to get the measurements for the front and rear of the bonnet (width), and the front and rear of the opening (between the fenders). I need reasonably accurate measurements. TIA! Steve

Geo Hahn
09-18-2004, 02:53 PM
This is from a 64 TR4 (straight, original) which I think will have identical sheet metal on the bonnet. Measured at places where I could get a straight metal tape across, measurements are the sheet metal, not including the chrome fender bead...

Width of the opening, at the rear, measured just in front of the bulge for the cowl vent (rubber gasket in place) -- 46 15/16"

Opening, front, measured just behind the hinge arms -- 45 11/16"

Bonnet, rear, measured at rearmost point -- 46 9/16"

Bonnet, front, measured at frontmost point but not as accurate as above as tape had to bow slightly across leading edge of bonnet nose - 44 3/4"

The gaps are even front to back and 1/8" with the fender bead in place... probably 3/16" w/o the bead on there.

Others have had this problem -- I think it was due to the inner fender being 'tweaked'.

If anyone else cares to measure... it wouldn't hurt to get 2nd & 3rd opinions though I don't think TR4s have as much variation in body dimensions as the TR3s have.

BOXoROCKS
09-18-2004, 06:32 PM
Stand it up on its back end then measure it X wise from underneath to see if it is square.

MDCanaday
09-21-2004, 12:20 AM
Steve, when a 4 gets hit it pushes the grill support panel back, taking out its natural bow and spreading the aprons appart. Pull off the wings and grill , flex the grill frame forward and with a block of pine and a #3 alignment tool, adjust the aprons inward untill you have the desired dimentions. This can be harder than it sounds if the valance panel is deformed also. Its hard to measure the total distance foreward from "straight" it has to be , but on my 4 its 1.5in more or less. There is a peak at mid point.If the damages are too bad seek help from somebody who is familiar with the TR's....
MD(mad dog)

Steve P.
09-21-2004, 12:46 PM
Mad Dog hit the nail on the proverbial head. The panel behind the grill is tweeked. The support rods that go from this panel to the fenders were also bent...the front of these rods were bent down 90 degrees instead of being straight. All of these have been corrected to the best of my ability, but there is still a 0.5" gap between the bonnet and the wings, but only at the front. Groan...I hate bodywork! To add to the misery, it looks like the bonnet has been futzed with. The round spots above the headlights aren't quite as round as they should be.

One more question; if I look along the inside of the fenders, where the bonnet opening is, should it be perfectly straight, or should the fenders draw in slightly at the very front? /ubbthreads/images/graemlins/cheers.gif

Geo Hahn
09-21-2004, 03:36 PM
[ QUOTE ]
One more question; if I look along the inside of the fenders, where the bonnet opening is, should it be perfectly straight, or should the fenders draw in slightly at the very front? /ubbthreads/images/graemlins/cheers.gif

[/ QUOTE ]

Without looking I would have said 'straight' but laying a straight edge along the side of the bonnet I see that there is a slight bowing in... most of the change back to front is simply the angle (rear edge & rear opening are wider than the front) but a small amount is due to a curve along the sides.

I don't know if pictures would help but I can send some if you think it would.

Steve P.
09-22-2004, 11:01 PM
Gents,
Thanks for all of the help and suggestions. I finally figured out that the bonnet is where most of the problem is. Based on dimensions given previously, my bonnet is 0.75" too narrow at the nose. I had suspected this all along, but the funny thing is its not at all obvious. I finally discovered that one of the headlight 'bumps' in the bonnet is taller than the other one, and they are not symmetric. I verified this by using a piece of cardboard and sketching the outline of one of the bumps, cutting it out and flipping it. When it was compared to the other one the difference really stood out. Guess I need a new bonnet. Too bad as this one is actually in excellent condition otherwise (nice, original paint and no rust). /ubbthreads/images/graemlins/cryin.gif

BOXoROCKS
09-23-2004, 11:07 AM
Find the true centerline, then find out how much one or the other side is tweeked. Secure bonnet then press and pull till square. You have a template of the headlite pods which you will use latter,and there should also be a high spot or ridge running from the out of round headlite pod to the edge, to find it use a flat long sanding board and sand at right angles over the high spot.when found have some way to pull the bonnet while using a 2x4 laid on the high spot and gently hammer the 2x4 all along the high spot, you will even be able to get the pod to the correct radius. Just use commen sense and you will save the bonnet. If you can't get it perfectly flat go for a small lowering of the dent and use lite filler.