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Discussion Starter #1
Hi Folks,

I've had a fun day pulling things apart from my engine, ultimately working towards a head gasket replacement.

I'm tackling this with the engine in the car.

Just a few questions regarding the intake side of things as it seems quite a challenge to remove some of those components....

1. Is it possible to remove the air box? Seems a bit difficult to get to the underside bolts.
2. Is it possible to remove the air box and carburetors together? Again the underside bolts seem challenging!
3. Is it possible to remove the air box, carburetors and intake manifold together? However once again, the underside bolts seem a little challenging!

The owner's bible seems to have one sentence on the matter... "A carbureted head is removed with carburetors in place."... So just to be clear it's telling me to remove the head with all the intake components attached? Which possibly then implies "no" for all my questions above!

Anyway, it's been a fun day getting my hands dirty... appreciate the feedback. Am starting to see the benefit of engine removal for ease of access! ;)

Cheers.
 

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Fiddly to remove air box, but doable with a small 1/4 inch drive socket and extension for those 4 bottom nuts. If I recall, you may be able to get at some with a longer extension from above, but maybe 1 or 2 will need a short extension accessed from the underside.You have to feel for the nuts, and you are bound to drop some nuts and washers along the way. When you put them back, put a second nut inside the socket.
I think people have removed the air box together with the carbs, but probably even fiddler...Lots of 16th turn work for the hardest to get to nuts.
You will need to detach the carb support which goes down to the engine mount, and that is harder with the air box still in place, the carb earth strap, accelerator pushrod...
I considered this approach, and even started to do it once, but on balance found it easier to get the air box out first....much easier to then see and reach everything else.
Adding in the manifold to the equation....I don't think I'd attempt that myself....too far and harder still to reach the nuts with everything in the way.
And you can indeed take them all off with the head. Others may in fact say that it is indeed easiest overall, but you still have to get at and disconnect some bits by feel. I've not done it that way.
Have a go at the air box, you may be surprised. You pretty much have to hug the air box to find/collect/replace the washers and nuts underneath. Lots of visualising and sticking out your tongue is required. A light and a mirror will help you see what you're up against, plus a magnet to catch bits, and help you decide which way you want to go.
Third or fourth time you do this will be a snap.
 

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Discussion Starter #3
Thanks Ranz, appreciate the verbose reply.

Yes, in my mind I had expected it would have been air box off, carburettors off, intake manifold off... all of which would have gradually created more and more space to work!

Although I've done plenty of reading, hadn't encountered info about the carb earth strap before! So thanks for that nugget too!

Space seems super tight in there, but based upon your experience, I'll give it another go with the 1/4 inch drive socket!!

Love the optimism that one day it'll be a snap!!......

Thanks again.
 

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Yes you can get the air box off.

A short 10mm wrench works better then anything else.

Once off leave the carbs on the manifold and remove the 7 13mm nuts holding the manifold to the head.
 

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Don't forget to disconnect the battery before you start reaching blindly under the airbox with a wrench. It's been about 40 years since I did this on a Weber engine. I removed the airbox with a 1/4 ratchet and a few extensions in order to get as much movement as I could per swing. I don't remember it being very difficult. The hard part comes when you try to pull the head up over corroded studs.

Good Luck
 

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Discussion Starter #6
Thanks guys.. persevered based upon your feedback.

Also helped having some good tools. From the front of the car, the first three were quite straightforward. The last one was a bit difficult but got there in the end!!

Time for a good clean too!!
 

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Discussion Starter #7
For those interested, I ended up taking the carbs off... seemed the easiest option in terms of accessing the 7 intake manifold nuts. Wasn't too painful, also discovered that earth strap!!

Now for the intake manifold, 6 out of 7 nuts were doable.

There is one nut that doesn't seem to take a socket or an "s" style wrench. Bit of a nut buster!! ;)

Anyway, decided to proceed with the head removal and worry about that nut removal later.... any tips on that last nut? It's the bottom one closest to the front if the image is not clear!
 

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You may wish to consider pulling the starter and sending it out for a service/refurbish/replacement... you are closer to it now than you ever will be again..... until it stops working, frustratingly intermittently, during a cold winter, when you need the car, add loved ones.. which is when you will warm your hands in glee as you remember how easy it was to remove the airbox, carbs, support, etc.... to get to it
 

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There is one nut that doesn't seem to take a socket or an "s" style wrench. Bit of a nut buster!!
Your photo shows some non-factory hardware - they look like non-metallic washers - behind that "problem nut". This may be contributing to your difficulty by spacing the nut itself further out from the head. I wonder if your 1750 wasn't originally set-up for Spica, and as such, has longer studs. Some PO may have put a stack of washers behind the nuts instead of installing shorter studs.

A simple fix is to simply hacksaw off the excess stud length(s) and use a die to extend the threads.

Anyway, decided to proceed with the head removal and worry about that nut removal later....
Yea, makes sense - everything is easier on the bench than when parts are still in the car.

Keep in mind that the head is fairly heavy, especially when you are reaching out over the fenders trying to lift it. The manifold will add a little more weight. The head has to rise absolutely parallel to the studs or else it will become jammed. So it helps to have two people lifting from either side, or to use a hoist to support the head while you guide it up.
 

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Discussion Starter #10
Thanks Jay.

That front nut it appears was holding onto some form of heat shield???? I'll post some more photos if there's any interest? Standard issue or not???

Eventually I managed to pry that last nut loose and remove the intake manifold, probably breaking all sort of rules....

I firstly used a tube spanner as it seemed to fit perfectly, however the nut won and rounded out the tube spanner!!!..

My second attempt used my 1/4" socket as it seemed to grab the nut "mostly", and coupled with a few adapters to connect it to my 1/2" breaker bar that managed to get it moving!

I'm curious, given there's a lot of torque specs out there for all these components, how does one actually use a torque wrench in the refitment given all these tight spaces and bespoke tool combination techniques!!!

Anyway, touching on a few points in this reply.
 

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Discussion Starter #11
And thanks for the tip Craig.

It's been interesting to see the rest of the components with these engine components out of the way...

My starter motor certainly looks a little crusty. And I admit, recently when trying to start, turning the key seems to do nothing. It just turns with one click and then nothing happens. Subsequent attempts seem to get things moving again. (Brand new battery recently installed so I can rule that out!).

Anyway, I appreciate the thought. Might be the right time to think about this too!
 

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Discussion Starter #12
Well after all that, time to lift the head! I optimistically thought my engine would be the easy one despite all those gone before me... ;)

Well as you might have guessed, I was wrong. That sucker is on there tight!! Anyway, I'll worry about later.

Regarding camshaft alignment, I'm guessing I should address this? One of them was spot on, the other a little off.
 

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Did you remove the (2) M8 bolts that are upside down at either side of the front cover?

One trick to removing the head (with all nuts and bolts removed of course) is to stuff equal lengths of rope into the #1 and #4 cylinders when they are in the down position. Then rotate the motor. Head should lift off enough to break the seal. If still no go, then start soaking the studs with PB Blaster or similar...
 

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Discussion Starter #14
Copy that.. got the two underside bolts too! ;) Thanks for mentioning it.

Soaking is underway....

I was thinking about going down the "head lifting tool" route....
 

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I’m fairly sure setting the cam timing is more complicated than just aligning the marks on the cam with the mark(s) in the journal cap... as you can see, there are actually two marks on the journal....

Somebody else will be along in a moment to explain, correct (hopefully) ;)
 

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Re "Heat shield"...
If what you are referring to is the rust-coloured, tubular-ended piece shown in post #7, it receives one end of an air intake hose, the other end of which goes to the second air cleaner inlet hole in the nose of your tubular canister. At some time that hose has fallen or been taken off.
If you do in fact have that two-inlet canister, the second hole is for a 'winter' setting, drawing warmer air through that hose from down near the motor, opened/closed with a lever-operated flap.
Now, I always thought cold air = good, warm air = bad, with engines, but I guess there comes a point where too cold = more bad. I don't know how cold that is.
Does someone out there have an original owners manual with relevant info? Be interesting to see what it said.
 

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Cam timing is something you worry about when you put the head back on. Kinda of pointless at this stage.
 

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Discussion Starter #18
What a treasure trove of information... thanks all for sharing the wisdom!

OK, was just thinking about my next move... I guess I'll focus on the head removal phase before getting too far ahead of myself! ;)

Wanted to confirm... the notes I've made from my reading make a point of note rotating the crankshaft... this is just in relation to the head being off and preventing any cylinder sleeve movement, yeah??

Thanks again. Appreciate the input.
 

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Jim's right but since I'm on vacation I've got nothing but time.

More than likely when you removed the timing chain you first loosened the idler gear and then tapped the chain to introduce some slack. The intake cam rotates away from the timing mark on the cam. Make note of the position (actually you did since you took a picture).

There are a couple of ways to time the cams. The correct way is to remove the nut and bolt from the veneer wheels (The series of holes around the cam sprocket). Then loosen the 22mm nut at the front of the cam which then allows the cam to rotate independent of the sprocket. With the crank already set at TDC, tighten the chain and idler gear and then move the cams to line up with the marks on the cam caps. Once there, tighten the 22mm nut (don't forget to bend the lock tab). Now, the trick is to find the holes in the veneer wheels that line up so that the bolt you removed will fit. This will likely require you to rotate the motor. Reinstall the small bolts (don't forget cotter pins or safety wire for the castle nuts) and rotate the motor thru a couple revs and verify that the cam marks and crank marks are all in agreement. Remember, this is an interference motor which means that if you've got something really off the pistons can hit the valves. Don't force the crank when rotating...

The other way (assuming the cams were in good timing to start) is to not touch the veneers. Install the exhaust cam with the mark a little to the outside of the cam mark. lay the timing chain on the sprocket and then rotate the cam until the chain tightens. If you got it right, it will fall into alignment. If not, rotate back move the cam back one tooth on the chain and repeat. Make sure you don't pull too hard and disturb the TDC position. Once the exhaust cam is aligned, move on to the intake side.

With the idler gear compressed all the way in, adjust the intake cam so the alignment mark is to the inside of the cam cap (look at your picture above to get a clue as to how far in). Now lay the chain across the sprocket and with luck you have enough slack to attach the two ends of the chain with the master link. Don't bother to install the link fish yet as more than likely you'll need to do this a couple of times.

Release the idler gear and pull the chain snug (never over tighten a chain, it needs a little slack to operate properly). Tighten the Idler gear, The intake cam should rotate back into alignment. That's the goal anyway. If not, loosen the idler gear again, remove the master link and adjust the intake cam and try again.

Although the second method sounds more fiddly I find it easier and quicker then the proper method - SO LONG AS THE CAMS WERE ORIGINALLY IN GOOD ALIGNMENT. If the chain was replaced, head shaved, and/or different thickness head gasket it will be different and you must use the veneer approach.

My biggest issue with the veneer approach is the opportunity to drop something down into the bowels of the motor. This may be my own private hell but I try to avoid it.

BTW, when it comes time to set the valve to tappet clearance (lash), it's way easier to do with the head on a bench...
 

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A quick tip on cam timing the first way Rich wrote.

If you know cam timing is going to change. When you undo the small veneer bolt. Remove it and put it in from the backside. When you go to rotate the cams you can easily remove the bolt rotate the cam and then find the new hole it needs to go in. You can then tighten the big nut. Then rotate the engine around until the veneer bolt is up top. Take it out and put it in from the front.

By doing it this way you don't take the chance of loosing your cam timing when you have to rotate the engine.

Also stuff lots of rags underneath the cam sprocket before removing the bolt. Makes it easier to find when you drop it.
 
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