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Help - identifying correct intake manifold


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One proble I have had with this very long (7+ years) restoration, is that things are misplaced and things are forgotten. Case in point, several weeks ago the shop called to report that the rolling chassis was ready and would I like to drop by for a look - see. I was very pleased, but pleasure turned to disappointment when I closely examined the intake manifold. This is my 3A engine TS58525E, but the manifold appears to belong to a 4 or 4A. Correct?

 

DSC01000.jpg

 

Lst night was the first opportunity I had to search for the original manifold. I think I found it, but I am not sure. here are some pics I took. There is a casting number - hard to make out, but ending in 119.

 

DSC01020.jpg

 

DSC01019.jpg

 

DSC01023.jpg

 

Please , could you chime in and provide a consensus? if not correct, maybe I can find one at Stoneleigh!

 

Cheers, Frank

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Frank the manifold on your engine is late 3a/3b and early TR4. the other manifold 302119 is the correct one for your chassis number.

Stuart.

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Stuart, you are absolutely right.

I have a 3b car with matching engine number, though I hadn't realized until now that I have the earlier manifold without the boss cast on top. Is there any difference between the two regarding performance?

Simon.

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The TR3B was assembled, advertized and sold as having a TR4 engine (and gearbox). Therefore one might assume that the TR3B would also have the manifold used on the TR4.

 

Yes Frank the dirty one in your photos is the correct one. See mine.

Edited by Don Elliott
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Stuart, you are absolutely right.

I have a 3b car with matching engine number, though I hadn't realized until now that I have the earlier manifold without the boss cast on top. Is there any difference between the two regarding performance?

Simon.

Not so you would notice. The best one is the late 4a manifold but you then need HS carbs as its a longer manifold and H6s would foul the choke levers on the inner wings.

Stuart.

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Frank

Manifold from my 1958 3a engine serial no 25750 same as yours!

Looks like you have the correct manifold fitted already as your serial number is pretty late (58525)

The dirty one without the boss is a 3 or early 3a manifold.

Unclepete :blink:

 

 

Edited by unclepete
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The best one is the late 4a manifold but you then need HS carbs as its a longer manifold and H6s would foul the choke levers on the inner wings. Stuart.

 

Frank

 

I have the 4A set-up on TRK i.e. the 307455 manifold with 1¾" HS6s and although I needed to re-route the choke cable the HS6 linkage doesn't foul the inner wings like the H6s. This set up lets the engine breath better and is generally considered the best ‘standard’ set-up for a little extra power - ask Baldrick, as his twin-carb TR6 can't keep up! :lol:

 

 

 

Cheers

Andrew

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Pete - My 1958 TR3A (TS 27489 LO) has the original parts including the manifold and the banjo fittings on the braided fuel lines (see photo above) to the float bowls that were on the car from new. My engine number is TS 27789E and this too is original.

 

May I suggest that the manifold and carbs that are on your TR3A (engine no. 25750) are not the originals. If your engine is the original engine, I would guess that your TS No. should be around TS 25450. Is this close? Your engine number is lower than mine and your carbs have the rubber fuel lines that are pushed on. According to Bill Piggott's book, the change to this type of carb was made "during late 1958, at around TS 40000". (Page 70)

 

Therefore it is also possible that your manifold with the cast boss on top is from a later car.

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Don

Not far out - TS25733 - engine 25750 but then she is an original right hand drive Jan 1958 (happy 50th)

I got the manifold information from parts catalogue part no 305547.

The boss casting was an early experiment with emissions control

I guess the CKD Left hand drives were different - as far as I understand the factory were not too fussy about what 1 3/4 high port inlet manifold came out of the parts bin and would often use older stock if it made little or no difference!

Bill Piggot often refers to whole batches of cars being produced with components 2 or 3 years older!

I would have liked the banjo type tops to my carb float chambers but they wern't available at the time of her rebuild (one had snapped off) so both float chambers got changed to the later type.

Roll on spring

Unc :blink:

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Hi all,

 

Frank, there are conflicting records as to when inlet manifold 305547 with the boss was introduced, and your engine TS58525E could very well have had this manifold fitted from new, as Unclepete says. This engine would have had the later SU carbies with push on fuel lines.

 

The boss cast on top of the inlet manifold balance tube was introduced in response to a USA government notice to car makers of a future regulation requiring closed circuit breathing for engine vapours. The boss was there ready to be tapped and fitted with a socket to take vapours from the rocker cover, but it was never used for that purpose.

 

When closed circuit breathing was introduced on the TR4 at engine CT14234E, engine vapour went through a flame trap into the aircleaners. The new TR4A curved flow inlet manifold had a different horizontal socket threaded into the balance tube for engine vapours via a PCV valve.

 

However, the boss on the later 3A inlet manifold eventually became useful for tapping in a vacuum line for a power brake upgrade.

 

Regards,

 

Viv.

 

PS Frank, further cross checking of records indicates the boss manifold wasn't used until the very last 3A's, so 302119 is the correct inlet manifold for your engine

Edited by vivdownunder
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Pete - The sportscar parts supplier here in Montreal recently ordered two new brass banjo fittings (one with inlet & outlet for carb #1, the other with only an inlet for carb #2) for me (from UK) so I could fabricate my own spare fuel line using these new banjo fittings and new fuel resistant tubing. My need stems from the problems I had last summer when I had to buy and use petrol in USA that had 10% ethanol added (it's all like that and you can't get petrol without ethanol) and I got what seemed like fuel starvation or vapour lock. That was with my original set-up with the 49 year old (original) rubber braided tubing. Some suggested that maybe the ethanol was swelling the ID of the old original rubber tubing to cause a flow blockage. After disconnecting it all on several different occasions, my pump always showed a good fuel supply while my float bowls were empty. After re-assembly, it would suddenly work again for a day or two. Then the same problem would come back. On one of these occasions, I was working at noon-time under a shade tree on a sunny day, only a mile or so from where Frank lives. It was to his place I was trying to get, but couldn't. Frank is the person from Pennsylvania who started this thread on the topic of manifolds. Thanks Frank for the offer.

 

My first temporary solution was to only drive in Canada where some petrol pumps do not have the added ethanol. The second (hopefully) final solution might be the new hose and banjo fitting assembly. While I'll have to use small non-original hose clamps to secure the new tubing, I'll carry the original set-up for installation at concours shows.

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The boss was there ready to be tapped and fitted with a socket to take vapours from the rocker cover, but it was never used for that purpose.

 

Bit off topic: I've tapped a socket into the boss for a brake servo. I will not install a servo, but it's nice to have the socket pre-installed if I ever want a servo.

 

Menno

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