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TR4 Bonnet hits carbureteur


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Hello

I have a 1963 TR4 and I notice that top of the front carb pot rubs against the bonnet in the bulge. There are clear signs of repairs to the metal work of the underside of the bonnet and the brass damper cap on the front carb has been either filed or worn down. The front carb has part number AUC6040 which according to this link means it is the correct part for my car.

https://rimmerbros.com/Item--i-AUC6040

The bonnet sits roughly in the right place on the car - at the front and no signs of being majorly misaligned with the rest of the body work. There are two bolts holding the bonnet hingesĀ on each side that I can loosen and move the bonnet up (potentially at least as they are a bit stuck for now) but even if I shifted it up as far as the hinges would allow I am not sure the damper cap would have more than a couple of mm clearance.

What clearance should I expect between top of carb damper pot and bonnet bulge?

Thanks

Tom

IMG_3845.HEIC IMG_3846.HEIC

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Tom - make sure the manifold is properly seated against the head and what manifold are you actually using - this shouldn't happen!

I can't open your photos - are you able to repost them in a different format?

Cheers Rich

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Hi

check your engine mounts and make sure they are no taller than 40mm. Some 55mm mounts look similar, but are bigger and obviously lift the front of the engine up. You can use these but you need to alter the front engine plate or the chassis mount to drop the engine position in the car.

Ā 

regards

Tony

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Just for a quick indication:Ā do you get a finger between the steering rack and the hub of the cooling fan.

If yes, the engine is too high on the frame. Hope this is the case, this es easy to solve

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Tom,

Not a measurement I have ever looked at so I just put a piece of blue tac 30mm high on top of the front carburettor and closed the bonnet and it did not touch it.Ā  I only have about 6mm clearance between the leading edge of the radiator header tank and the bonnet. Radiator is early long neck type.

Sounds like the engine mounts are to big or there are no packers between body and chassis so body sitting low.

Neil

Ā 

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13 hours ago, Ransomes256 said:

the engine mounts are to big

I have just checked the engine mounts and they are approx 30mm. (photos attached in a better format this time, with a ruler for scale). So they appear to be within the correct range.

13 hours ago, Ransomes256 said:

or there are no packers

Where would I look to see if there are any packers? The body does seem perhaps a bit low, based on nothing more than a rough comparison between a photo of my car and others and the fact that I hear something scrape (body and wheel?) when I go over a speed bump....

(I will try to take some photos from a better angle for comparison.)

IMG_3871.jpg

IMG_3872.jpg

Untitled.jpg

Edited by solaise
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Front body mounts are nominally one thick rubber then the ones on the turret support are one thin rubber one ally spacer and one thick rubber. if you dont have this amount then thats possibly where your problem comes from, looking at your picture the car does look to sit a bit low on the front, the bulge is there to clear the carbs as thats what its for as you can see.

Stuart.

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Thanks Stuart. Does this image show the placing and quantity spacers you are referring to? (44-48 for the front body mounts and 49-56 for the turret support)

GRID200679.jpg

Ā 

I will check for the existence of these parts in the quantities indicated.

Tom

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Its actually this one for a TR 4 TR4 Chassis but yes they show the position of the packers and a nominal amount obviously it depends on the car as to whether you need to add or subtract shims.

Stuart

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Just as a data point, I have Land Rover motor mounts in my TR4A, plus I added 1/2 inch (approx) spacers to them so I could easily change the fan belt. The HS6 carbs Iā€™m running have no clearance issues with the bonnet.

Jim

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Ā 

18 hours ago, Z320 said:

Ā do you get a finger between the steering rack and the hub of the cooling fan.

Yes I can get a finger in there, so roughly 15mm gap. (see photo) but the engine mounts seem correctly dimensions (30mm). What would you expect this gap to be?

Tom

IMG_3877.jpg

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19 hours ago, rcreweread said:

what manifold are you actually using

If I have read correctly is looks like "304164" ieĀ Exhaust Manifold - High Port Head - 304164

Is this correct?

Tom

IMG_3879.jpg

IMG_3878.jpg

Edited by solaise
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23 minutes ago, solaise said:

Ā 

Yes I can get a finger in there, so roughly 15mm gap. (see photo) but the engine mounts seem correctly dimensions (30mm). What would you expect this gap to be?

Tom

IMG_3877.jpg

That's a bit more asĀ it should be, but your engine is not too high on the frame.

Interesting to see: a previous owner had the hub on the lathe Ā to make this groove in the hub.

But your inlet manifold is not what I have on my 4A and I don't remember this designĀ 

Edited by Z320
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8 minutes ago, ntc said:

I would be checking the gearbox mount

https://www.moss-europe.co.uk/external-gearbox-tr2-4a-1953-67.html

Looking at this diagram, are you suggesting if part 85 was too thinĀ then the gearbox would sit low and hence the engine would tilt upwards more than desired?

For info - Is the engine held in position by 3 points - the two mountings at the front and the gearbox mount at the back?

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1 hour ago, Z320 said:

That's a bit more asĀ it should be, but your engine is not too high on the frame.

Interesting to see: a previous owner had the hub on the lathe Ā to make this groove in the hub.

But your inlet manifold is not what I have on my 4A and I don't remember this designĀ 

Thats not been in a lathe its worn on the rack in a previous time I would say..

Stuart.

Edited by stuart
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As Stuart says the other way to solve this may be to shim up the front body mounts and those on the link to the top of the front suspension turret.

As I remember both can have substantial fibre spacers and aluminium c washers, so if they arenā€™t there the front of the body may be sitting too low on the chassis ?

The question could then be if you could just lift and shim the front without having to respace the whole body tub on the chassis ?

regards

TonyĀ 

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1 hour ago, stuart said:

Thats not been in a lathe its worn on the rack in a previous time I would say..

Stuart.

I agree. Mine was like that when I bought the car. A combination of a loose crankshaft dog bolt, tired engine mounts, and a sagging chassis.

Pete

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Hi Tom,

I layed a straight wooden lath across the wings and measured for you to compare:

RYKuO3ZYafnKhQon1fP5zKe91k4jXQIqacHrEpF_

The top of my frontĀ SU HS6 is only some [mm] higher than the wings.

kFZQD64gx-K1R_G2KWWhadlWP0HOBv0Deq9pL7bW

While the top of the valve cover is about 53 mm lower than the wings.

JGqYz3_5Y6v8oUz9T1zwx8tkHCCWSFOfjM5xh1pE

My thought are on your inlet manifold.....

I hope this helps.

Ciao, Marco

Edited by Z320
My bad English
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The tops of your carburettors are a long way from the cylinder head (i.e. disposed to the right of the car) and I'm wondering if this means that, instead of lying in the centre line of the hump. they are losing the necessary clearance.

Your 2nd photo, showing the inside of the hump, seems to suggest that this might be adding to the problem.

I have HS6 carburettors now, and these have a shorter inlet tract and so sit closer to the manifold and, of course,Ā to the head.

Ian Cornish

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