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Intake/Exhaust Manifold Torque Settings?


MrTougéTka

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Hey guys I've been chasing a misfire/det for the last two weeks and suspected it to be a manifold gasket leak on my wee 4k in the second cyl.

So earlier I ripped both manifolds off and to my surprise found them really easy to remove?!

Gasket was near new condition, so I was thinking maybe previous owner didn't tighten them down enough? Causing the leak?

 

How firm can you tighten these bad boys down? 

 

Anyone know the torque settings? or can I just keep them tighter than a nun LOL

Just don't want to strip or round off the bolts... happy I've possibly found the cause to all this drama... cheers! 

 

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If you've got bolts holding your manifolds to the head, it is a good idea to replace them with studs & nuts.  whilst doing that, also get a one piece manifold gasket.  That will get rid of any manifold issues for a long while.

P.S.  Timaru NZ; nice place, I've been there once.

Cheers Banjo

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Are Timaru !

image.png.88874b02580d69b7df7134f01bbfcb01.png

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In another life, I once owned a Triumph 2500PI (Petrol Injection). Great car !

I can still remember the first time I ever visited N.Z.  Just couldn't get over the number of British Cars !   Now, it Japanese second hand imports.

P.S.    ebay link for 1 piece composite K series manifold gaskets.

https://www.ebay.com.au/itm/1974-1978-For-Toyota-Corolla-KE30-3K-3K-H-Extractor-Manifold-Gasket-/201510257673?hash=item2eeaf28409

From the Rollaclub Tech Pages:

Exhaust Manifold

The stock exhaust manifold is alright if you're just playing around trying to get your car running nicely. There are two types of stock manifold, one has just one outlet pipe, the other has two pipes and is similar to tri-y (4-2-1) extractors. Generally, as you add a larger cam, you need to have tuned length extractors and a larger exhaust in place, or all the extra air your engine is now moving is too much for the stock manifold to hold, and the exhaust gases pulse back up against the inlet charge and fuel comes back in a fine mist out of the carburettor.

Any extractors will do, new ones are about $280. You can pick second hand ones up for $50-$100, or sometimes even free if you're lucky like me. Second hand extractors tend to be a pest, in that either the middle pipe has bent out and doesn't like to seal, or the end pipe (usually the rear) is bent from a poorly hung exhaust pulling on it for so many years, and is hard to line up with the head.

I've always used second hand extractors which I got for free, and by far the best thing you can do to make the manifold easy to locate and seal is use studs and nuts instead of bolts. This also puts a more even force over the threads of the head, so you're less likely to strip a thread. The normal two-piece manifold gasket can also cause sealing problems if the middle pipe is bent, but an exhaust shop should be able to sell you a one-piece extractor gasket which is much better. You can get metal ones which are alright, but I like the floppy asbestos type gaskets which are difficult to get these days.

If your manifold gasket just won't seal, there's a chance the flanges of the inlet manifold and exhaust manifold (or extractors if you're using them) are different thicknesses. Any engine builder or machine shop should be able to grind the faces of the manifolds together for you, to ensure they're flat and sealing properly. This should cost you between $40 and $80.

_____________________________________________________________________________________________________________________________________________________________]

PERASEAL do a one piece gasket, which has the P/N EM30, available through Bursons here in Australia.

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I've used them on all my Rollas, & have never had a manifold issue since.

Cheers Banjo

Edited by Banjo
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They are only m10 or m12, shouldn't need much torque at all. the old "firm" but not tight is the key. Its all aluminium so don't swing off them. 

I never did change my 4k to studs/nuts on the intake manifold, but once i got a 1 piece gasket i also never had to undo them ever again. 

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Aftermarket extractors have an advantage that they are separate from the inlet manifold, & pull up to the head independently.  However, the flange tips of the inlet manifold & extractors can be different depths, making it difficult to get a thick washer to pull down firmly, & parallel to the head. You could probably grind down the thicker flange tip on the outside to match.

If you have a standard setup, then the inlet & exhaust manifolds are bolted together, with 4 off bolts.  If you can loosen these slightly (good luck), then pull the manifolds up to the head, (without gasket) then tighten the 4 off bolts holding the manifolds together. Remove the manifolds from the head, & they should now be in the same plane, across the mounting faces.   The problem with this suggestion is that the 4 off bolts will be so tight in the threaded section, (which is in the exhaust manifold), that they will break off, whilst trying to undo them, & then you have the need to drill them out & retap them.

Cheers Banjo  

Edited by Banjo
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2 hours ago, ke70dave said:

Run a flat file across the face, that will tell you how bad it is. if the file touches the whole surface as you rub it back and forwards that's about as good as it gets. 

Ive never had a manifold resurfaced....

So file the flanges or on the head itself I'm guessing? Both mannies are already off the car so should be a piece of cake, gaskets are pretty much brand new, so don't wanna end up buying another one if this'll fix it fingers crossed

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