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MG Midget and Sprite Technical - Frogeye parts - identification

Still working on my Frogeye bonnet restoration.
It came to me fully dismantled, wings cut off and dumped, various other bits in a box. Its coming together quite well now but before I weld on the front lower valance I need to sort out and fit some parts to the lower part of the radiator air ducting and locking mechanism.

Attached photo is of the bits I need to find homes for. Some I can determine from a photo that a helpful BBS'r supplied, but I still have some questions.

Photo first, then I will explain what I know and what I need to find out.



Guy W

Pretty sure that A and B are the same part, and I only need one of them! They are not identical in shape, but I think A is the better shaped one. It fits across behind the valance and acts as a reinforcing support to the bonnet catch which bolts to the square plate in the middle. The question is: The lower edge matches the curve of the valance; should it be welded to the valance along this edge?
C is the lower plate of the air duct. Question: does the square hole go on the left or the right, and what is it there for? I am guessing some sort of safety catch?
D, I know where that goes, but it is U shaped. Question: does the trough side point upwards or downwards?
E and F, obviously a pair, but I cannot work out where they go. They may be nothing to do with the bonnet at all!
G, likewise, I cannot find a home for it. I suspect there maybe should be 2 of these?
H and I: I assume these are the plates that the cranked bonnet locking rods engage with, in which case they must attach to the front chassis rails somehow?


Photo of where the bits are supposed to fit - I think!

Guy W

And from the inside:

Presumably some pins go through the two holes in the square lugs at either side, to locate with the chassis rail extensions?
What is that spring clip by the left hand hole - as seen in this photo ?

Guy W

Hi Guy
If you can still access the rebuild of John Clark's bonnet on the Amicale Spridget website it may assist.
Also the pics I sent you ages ago should assist. I can do them again.
A/B same part. I strengthens the air intake whilst also being the support for the locking mechanism for the bonnet. The locking mech' is a lock with rods that pass through the walls of the intake and into the two bracket last on your list which bolt onto the projecting chassis dumb irons.
A or B sits on C. The square hole goes on the left hand passenger side and the safety catch fitted to the nearside dumb iron hooks through the hole.
G is an exhaust bracket that fits to the bellhousing engine rear plate and attaches to a clamp on the exhaust.
The U channel is a strengthener.
I havent worked the remaining two parts out I'll have to look at my car..
The clip is for the bonnet support. Not found on many cars these days as well as the struts to hold the bonnet up there was also a prop that ran across the front of the radiator. If you want to fit one I have one somewhere that I can photograph for you.
Alan
www.masckent.org
Alan Anstead

Thanks Alan,
I do have your photos still; they are what I was referring to as supplied by a helpful BBS'r - that's you!
They help a lot, but I still needed a bit more explanation.

The front edge of part A aligns closely with the lower edge of the valance. On mine, the valance edge is folded back on itself, leaving a slot that looks like it might receive the flanged edge of part A. Is this so, are they also welded together along this edge?

Which way up does the U-shaped channel go? (part D)

I should have recognised G !!

Still struggling to orientate the plates, H and I. They have an odd bend in them. I will work it out eventually, but assume at this stage that they don't impact on the bonnet assembly process at this stage.
Guy W

H and I are attached to the front chassis rails using 1/4" set screws. The ends of the rails should have captive nuts. The holes in the plated are larger to allow for adjustment. E & F are a challenge! at a guess they look very similar to the brackets which hold on a works type hardtop.
D has the trough facing up. Great jigsaw puzzle!
Bob Beaumont

Thanks Bob, another bit worked out!

I have just been out to the garage and now see that the two plates, H & I are positioned vertically, not horizontal as I thought! And the odd bend in them must act to centralise the bonnet as it closes and to guide the locating pins (which I am missing) into the two angled holes in the tops of the chassis extensions.

I am also pleased that I haven't yet welded the front valance on as it is now apparent that I need to assemble these other parts for the bonnet locking mechanism and air duct first. The valance is all clamped in position and I was going to weld it this afternoon but decided to go for a walk in the nice sunshine instead. Lawrence would have approved!

Enough for tonight. Tomorrow I will offer up the bits I have and take some more photos for confirmation. Turning out to be an interesting task!
Guy W

Guy when you are ready to weld this all up I suggest you fit the bonnet to the car together with the radiator as the bonnet has a tendancy to 'curl', a bit like a banana, particularly if the wings have been removed. If you get the locking mechanism in the wrong place the bonnet can foul the top of the radiator (bitter experience!)It also affects the shut lines with the A post and top of the cill.
Bob Beaumont

Guy
You have e-mail (pictures)
Alan
Alan Anstead

Alan, thanks for the photos. Together with the ones you sent a couple of months back I think I can see how it all fits. Next issue will be to work out the welding sequence as I can see some difficulties with access if I do it in the wrong order! I would have welded in the lock mechanism support to the air box structure first, but now think it may be better welded to the valance off the car, and then offered up. Its still going to be tricky though!

Bob, thanks for the tip about the radiator. That is probably the next thing I need to do, although it is hard to see what options there would be if I have got it wrong!

I started out with the centre bonnet panel, stripped out by the previous owner, and stored like that for some years, so I guess it may have curled or uncurled a bit. I have welded on both the new front wings, with a fair bit of fettling to get them to match the curves along the beaded joints. All this was done with the bonnet assembly tried both on and off the car many times over. I got quite skilled at removing and replacing the bonnet on my own! It seems to fit OK, but the one thing I hadn't thought of trying is adding the radiator into the puzzle! Now you've got me worried, and just when I thought I was making progress!
Guy W

In my case, I had to slightly lower the radiator by re-positioning the captive nuts, although you can't go far as the radiator shroud can foul the steering rack. I also set back the radiator slightly using spacers between the radiator mounting uprights. It gave me 1/4" clearance between the top of the rad and the bonnet in the end.

I think it was always tight as the PO had glued a sponge pad to the underside of the bonnet as there was some evidence of the bonnet just kissing the rad. There was no evidence of any accident damage so I guess it may have come out of the factory that way.
Bob Beaumont

Following Bob's advice I installed the rad and then refitted the bonnet to check the clearance. I have a slight problem to sort out. The bonnet is very slightly high at the front - I need to get it lower by about 1/2 an inch. But it is already virtually touching the filler cap on the rad. The rad won't lower in its brackets even if I slotted them as there is no clearance to the chassis rail underneath.

After a bit of puzzling I realise that if I move the rad back a little, then the bonnet clearance will increase as needed. I then measured the horizontal distance from the top of the rad mounting stanchion, back to the top inner corner of the footwell face. They are pretty well at the same height. One side measures 23 1/2", and the other side 23 1/4" so at least one is wrong! Checking on my 1971 car they both measure at 22 1/2". This would set the radiator back as needed, but as the stanchions were replaced on my 1971 car about 18 years ago (by me) I cannot be sure that they are right either!

Perhaps someone with an unmolested car could take a check measurement for me please? The measurement needed is from the forward face of the footwell, top inner corner, forwards to the front face of the stanchion that the rad flange bolts to. Its just possible to thread a tape measure through for a straight line measurement even with engine and ancillaries installed.

PS, although this is an a Frog, I am pretty sure that the measurements would be the same on all models.
Guy W

22.625"
Alan
Alan Anstead

Thanks again Alan. Confirms my suspicions, and hopefully also gives me a reasonably simple solution to my bonnet alignment problems!
Guy W

Dooh! Wish I had thought of moving the rad supports. My 1/2 spacers do a similar job although the stanchions were not disturbed originally. At least your sorted now!
Bob Beaumont

Well as it appears mine are too far forward by quite a lot (5/8" and 7/8") so adding spacers wouldn't work too well. And anyway they are out of line so the rad would be slightly skewed. But this does take a bit of thinking forward! I wouldn't want to end up shortening the prop shaft in order to cure a slight bonnet misalignment!
(Move stanchions~move radiator~move engine mounts~ move engine~move gearbox=propshaft too long!)

On this car I replaced the stanchions, so their wrong positioning, and certainly their 1/4" misalignment is just down to me, so I better correct that. But I also replaced the forward extensions of the chassis rails (relict dumb-irons)so the question is now whether they are the fault, or the stanchions! The dumb irons extend 8.5" forward from the forward face of the front inner fulcrum brackets. But at least they are both the same!
Guy W

Don't worry Guy - there's about an inch or more of free play in the prop, taken up in the sliding joint into the 'box.
David Smith

David, it was tongue in cheek comment, about the dangers of fault fixing if you don't properly identify the cause and go chasing after symptoms!
Guy W

In my case all the front end was fine and did not need any work. Good old leaky A series! Hence the repositioning of the stanchions did not occur to me.

One other point was that when I refitted the engine (1275) the K&N air filters that were originally OK also fouled the bonnet!!. I ended up buying new K&N's designed for a mini which had the intake holes etc on the backplates in the middle rather than the bottom.

The other point to watch when you move the stanchions is to ensure that the brackets from the stanchion to the inner wing still fit ok.
Bob Beaumont

It is possible to get KN Filters with blank bases so that you can position as required.
Alan
Alan Anstead

Good point about those brackets, Bob. I will need to search them out and check. But I suspect the stanchions are too far forward as I have them fitted, so perhaps the brackets won't fit now, but will after they have been moved!

If your dumb irons are original, could you measure the overall length from the forward face of one of the inner fulcrum brackets. I don't know if my stanchions are wrong in relation to the dumb irons, or if it is the dumb irons that are too long.

When I close the bonnet the holes that the bonnet pins secure through, are about 1/2" further back than the corresponding washered holes on the top of the dumb irons. Suggests that the dumb irons are too long. I just welded them on as they were. Maybe I should have trimmed the length a little before fitting.
Guy W

Ok Guy I will measure it up. I did experience the same problem with my bonnet ie the bonnet pins were behind the holes in the chassis when I trial fitted it. This is what I put down to 'bonnet curl'. In the end I moved the pins. It was quite a faff.
Bob Beaumont

Bob,
There seem to be two possibilities; move the pins or shorten the dumb irons. As the stanchions are too far forward maybe the dumb irons are too long, so shortening them may solve both problems. OTOH the bottom of the air ducting is partially missing and the remaining lower edges are a bit frilly so I need to do some reconstruction there too, and could shift the pin positions a little in the process. So I have 2 viable solutions.

The dumb iron length may just sway which way I go. If they are correct, or nearly so, I may alter the air box and just cut off and reweld the stanchions. If they are badly out then I will have to redo them first. There is some appeal to the idea of removing the dumb irons, setting the bonnet exactly right, with neat panel gaps, and then offering up the dumb irons to match the fitted bonnet position before re welding. Sort of back to front assembly, but it might work!
Guy W

Guy

Changing the length of the dumb irons(unless they are wrong) may also affect the postion of the anti roll bar securing brackets assuming you want to fit one of course.

I'll have a measure up later this evening.
Bob Beaumont

Yes, I had thought of that. There's more to this than one at first realises!
Guy W

I know what you mean. The work on the bonnet to ensure the shut lines were reasonable ( a little big above the cill even now) and getting it to close without hitting the rad etc took many frustrating hours. I also replaced the inner wings and despite measuring everything several times still had difficulties with the tie brackets to the stanchions needing adjustment. I guess working on a 50 odd year old monocoque bodyshell has its challenges.
Bob Beaumont

I make the overall length 2200mm from the front of the wishbone bracket to the front of the dumb iron
Bob Beaumont

Thanks Bob,
assuming that you have added a zero just for fun, mine are as close as matters the same.
Mine measure 8 1/2" = 217mm Add a bit of plus/minus for reading in the gloom under the car and I would say they are the same.

Need to dwell on what to do next then.
Guy W

Bob,
Thanks for pointing me in the right direction over the potential rad / bonnet clearance!

I have now added the rubber bonnet buffers on the sills and inner wheel arches (thanks to Alan for the positioning photos). I have also found a length of rubber fillet that seems to fit neatly into the rain gutter at the front of the scuttle and helps support the bonnet rear edge. With these additions to support the bonnet more accurately it is gradually getting the alignment right. Although I think the front of the bonnet is still maybe 1/2" too high - it isn't sitting quite as neatly down onto the curved sill tops as it should.

I haven't yet altered those stanchions, but used spacers to pack the radiator back to the correct positioning as measured from the front corners of the footwells. In my "what's this bit?" box I then found one of the two L shaped brackets that connect the stanchions to the inner wing. (the other will soon turn up now I know what to look out for!) And surprise, surprise, allowing for the bit of springiness it is misaligned at the wing captive nuts by exactly the amount that the stanchion needs to go back by for correcting the radiator position.

These may seem like small gains but considering that at the front of this car I have rebuilt both footwells, the scuttle, battery shelf, both sills, undersides of both chassis rails and replaced the dumb irons and stanchions. Then rebuilt the complete bonnet; so the fact that the bonnet is now fitting back on again as well as it is, is a major miracle!
Guy W

Guy

Yes my bonnet doesn't quite fit as well as it should along the sill top. However its better than it was before it was restored and the car had not been touched since it was originally built! Its got a nice line down the A post though!

The L shaped brackets are slightly different so its worth finding the other one and checking it all still lines up. I found I had to adjust one slightly, by welding about 1/2" to the radiator end.

Well done on the bonnet fit!
Bob Beaumont

Bob, I found the other L shaped bracket. Still attached to a frame containing a hefty square glass bottle. Presume its a period aftermarket windscreen washer bottle, but I've not properly investigated it yet. I had put the first bracket on the wrong side as you guessed!

Went to a big local show yesterday and found a nice, near original sprite to inspect closely, photograph and get some more check measurements. Very useful at this stage! Helpful and friendly owner. Like all Frog owners!

My dumb irons are just 1/4" longer than they should be. Not enough to correct the stanchions, even if I did cut the chassis and shorten them. So I am leaving them as they are. Its also better to have the ARB mounts too far forward than risk getting them too far back. At least I managed to get them both exactly the same length!

The locating holes for the bonnet pegs are still misaligned by 7/16". So a good part of that is accounted for by the longer dumb irons. I think I will resolve it by slicing off and repositioning the angled washer piece on the top of the dumb iron. That seems to be the easiest solution and at the moment I cannot see any down sides to doing it that way.
Guy W

Decided to modify the rad air box sides to lower the bonnet.
Slow job though, - it took most of the afternoon.

But at least it worked. I shortened the air box sides by 7/16" and now I have a nice even panel gap where the bonnet sits down onto the sill tops. And the bonnet locating pegs now also align with the dumb iron sockets too!

Guy W

Nice use of what looks like a wood chisel there Guy :).
Lawrence Slater

That's right Lawrence. Or nearly right. This is not just a wood chisel, its an OLD wood chisel. Relegated to cutting through spot welds after drilling the centre out. Very effective it is too. But NOT to be confused with my wood chisels which live in their own wooden case, get very pampered and only ever used for wood!
Guy W

Addendum, di-dum di-dum:

Actually a good sharp (old) wood chisel with the edge cut to a shallow angle on a grinding wheel is surprisingly good at slicing edge on through body panels. If kept sharp it will cut through with light taps from a hammer with very little distortion to adjoining metal. And you can get into corners where a hacksaw, slitting disk or nibbler just wouldn't cut it.
Guy W

Hi Guy

Good work!I assume the rad it still clear? By the way the square washer bottle is a nice period piece originally made by Lucas. It was a genuine factory optional extra so worth keeping.

We just got back from a long weekend with the Frog. Covered over 250 miles without a peep.
Bob Beaumont

"This is not just a wood chisel, its an OLD wood chisel"

I thought you were going to say -- This is not just a wood chisel, this is an 'M&S' wood chisel. LOL.

See the reason I knew, is because I too use an old wood chilsel for the same reasons. Excellent tool.
Lawrence Slater

Lawrence, it was intended to be a paraphrase of M & S . . . .

Bob, at the moment I have temporarily got a couple of slips of wood used to pack the rad back to the correct distance from the footwell fronts. And in that position the bonnet clears OK. But it is surprisingly close. As I don't have headlights fitted it is easy to see/ reach in to check the clearance which is probably about 3/8".

I presume this is OK but it occurs to me that most owners wouldn't know just how close the clearance is as I can see no way of checking without removing the nearside headlight.
Guy W

:).
Lawrence Slater

Guy
It is very close as you say. The clearance reduces when the rad gets hot and expands. 3/8" sounds ok though.
Bob Beaumont

The bottom of my rad, on the nearside, has a lower section that forms the feed to the bottom outlet hose. This is directly above the nearside chassis rail and limits how low one can drop the rad. I don't know if all the vertical flow rads are the same, but it is a close fit and seems a poor design. If the sloping side of this lowered section was an inch towards the centre line of the car it would give far more scope for adjustment.

My rad is currently positioned with temporary spacers at 22 5/8" from the front of the footwells. This matches the dimension that Alan posted, and is the same as the car I measured last weekend so I believe this is correct "factory". Bob, assuming your rad position (with the spacers) is the same what sort of clearance do you have between the fan and the rad? Or do you have an electric one with your 1275 engine?
Guy W

I am using a later 6 blade plastic fan which works fine. Even in this recent spell of hot weather the temp never went over 190F (or the N on more modern guages!)and I have been to the South of France in temps well over 30C and all is fine. (I am using a 13 row oil cooler so that will help) There appears to be plenty of room between the fan and the rad but I will measure it and post an update.

I had the rad rebuilt recently (it had started leaking) and toyed with the idea of changing the shape of the bottom section. It was going to have to be fabricated and was really expensive. Dropping it substantially also meant the radiator ducting had to be adjusted as it would foul the steering rack!

I did get the rad restorer to move the captive fixing nuts up 5mm and that gave me a little more room The bottom of the rad is still 5mm clear of the chassis rail

Moving the rad captive nuts and the spacers did the trick for me and there is no evidence of any bonnet/rad fouling now.
Bob Beaumont

Thanks Bob,
I think mine is going to go together OK, but there isn't a lot of leeway for adjustment if I do get bonnet contact. So I was looking to see if there were any other adaptations that would be easier to deal with at this stage, and that may avoid problems later!

Another possibility would be a small chamfer on the inside top edge of the n/s dumb iron - a bit like the later 1500 shells have to clear the bellhousing. It would allow the rad to be lowered a bit. But then if that just introduces problems with the hoses and the steering rack then that's not such a good idea.
Guy W

Hi Guy

Measured the gap between the fan and the closest part of the rad which is the upper header tank. Its a bit of a fiddle around the cowling but I make it 200MM or about an inch in old money so plenty of room.

Off on hols for a week today so won't be posting for a short while. Good luck with the fitting.
Bob Beaumont

Thanks Bob. Another freebie zero in there I presume. 200mm = 8". I think you mean 20mm ! Enjoy your holiday!
Guy W

This thread was discussed between 15/07/2013 and 02/08/2013

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