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Discussion Starter · #1 ·
Hello,
have today had to accept the head gasket(s) on my 1995 24v 3.0 164 are blown. Been a few months of various coolant leaks at variety of pipes, which now understand was due to over-pressurisation due to headgasket leak. Can smell fuel in the expansion tank.
My plan is to spend a month prepping to ensure have all the parts/tools to hand.
Questions are:
1) do I have to drop the engine to get the rear head clear of the bodyshell or can I use a hoist to tilt it forwards?
2) Can I remove the cams/housing as complete units without having to split them?
3) Understand can reuse the studs - anyone know any different?
4) Please remind of retorquing order and process.
5) Do the heads need to be skimmed?
6) Any suggestions for brand of gaskets? Ajusa is readily available? Any thoughts compared to offerings from Alfa?
7) A mechanic thought he could hear bottom end slap but am hoping that was just piston slap. Any thoughts?

Determined not to scrap the car and a plus is I will now be able to put in new knock sensors. yay.....

Thanks in advance.
 

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If I was faced with this task, I'd drop the entire engine and cradle out. Drill some holes through the cradle into the frame so that you can use some pins to properly relocate it when you reinstall.

You can get to everything, easily, if you drop the cradle.
 

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Discussion Starter · #4 ·
Thank you both. I don't have facility to remove the engine so lowering seems only viable route. Noticed the subframe has some locating tabs at the front - does it all need to be moved back a bit to free the tabs before it can be lowered?
Did you skim the heads? The block?
 

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I've lowered the rear to do a steering rack. I've not taken it all the way down.

You'll only skim the head if it's not flat or there is corrosion. When you take the heads off, make sure not to rotate the crank, and it's best to put hold downs on the wet cylinders. You don't skim the block. It'll become immediately apparent why when you take off the heads.
 

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Discussion Starter · #6 ·
I've lowered the rear to do a steering rack. I've not taken it all the way down.

You'll only skim the head if it's not flat or there is corrosion. When you take the heads off, make sure not to rotate the crank, and it's best to put hold downs on the wet cylinders. You don't skim the block. It'll become immediately apparent why when you take off the heads.
Many thanks. The rear seems to lower fine, though lowering the front to cant the engine forwards seems trickier because of the tabs.
 

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Tabs? Photo please.
I like the concept of lowering the back of the sub frame to get to the steering rack...another thread for that one.

Yes, I have read in any number of places where you have a real beach of a time getting the rear head off the studs if you don't cant the engine.

While you have the heads off...be sure you check the knock sensors. Mine were broken and fell apart when I took them out. Now is a great time to install them. Jason at Alfissimo has some in stock.

Do you have the head gasket set? Hopefully, it will come with the two Orings for the water tube between the heads.

Number the connectors with a paint pen to the coils so you don't mix them up as I did.

Do you need to get to the starter? It will be right there with full access.

Put a rag or something into the hole on top of the transmission bell housing. Nuts, bolts, and sockets have a way of conveniently falling into that hole, necessitating the removal of the transmission to get that stuff out.
 

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Richard,

I have done this with engine in situ on both 12V and 24V. I believe I just had to lower the subframe a bit in the front, might have needed to lift the engine a bit by removing the rear motor mount bolt. Standing on top of the engine to lift the head is pretty uncivilized work so I would not argue that removing the engine is more appropriate. I have always removed the engine from the top with a hoist (except on Q4), leaving compressor in the car. Removing the whole subframe is more work, IMO. I guess the choice is somewhat informed by the tools at your disposal.

highly unlikely you’ll need to skim the heads. They won’t look all that pretty, and you can clean them up a bit if you wish. I'd leave the critical surfaces alone.

Torquing the heads specifies 25Nm + 240 degrees. It is a ton of torque. I use a 30” bar and an old school gauge (see my post on the 3.2 Q4 build). I remember finding it very difficult to do this in the car. Having a second pair of hands to hold the gauge might be the trick. I did in 80 degree increments this time. Oil the threads. Torque sequence is in the shop manual in the engine torque section .

1690102


1690103


Pretty sure you do have to remove the cam sprockets to access one of the bolts that secures the engine mount bracket, which in turn restricts access to the front cam bearing cap on the rear head.

It can be really hard to break the taper on the cam sprockets. I would use a 3/8” extension and tap from behind. Heat might help, but I worry. I would research strategies a bit more here on the bb.

Get new o-rings for the black pipe. I measured them and bought them on o-rings.com but safer to source through an Alfa parts specialist.

I have a generic cam sprocket tool that works fine. You’ll need one. https://www.amazon.com/Performance-Tool-W89208-Pulley-Maximas/. Totally Alfa is a great resource for tools, but I did find the cam sprocket tool did not work for me. Many of their items are catered towards 916 24V engines, and there are just enough differences such that the tools differ.

I’ve never had an issue with keeping the crank in place and have always just used the reference mark on the block for TDC.

Obviously new cam seals, oil pump seal, plug well seals, valve cover gaskets. I would consider a water pump unless you know the history of yours well. I have always been happy to have removed mine. In one case I had block damage from corrosion due to coolant left in too long, so much that the gasket surface was compromised, leading to perpetual slow gasket leaks. On another case the impeller was rusted badly. I would at least remove it, inspect, and feel the seal (should offer some resistance). Inspect cam belt idler bearings as well. ideally there is still some preload. Certainly no wobble. These are parts not worth ordering until you assess the condition of yours, IMO.

I use simple green and toothbrushes to clean things up, and evaporust to remove oxidation from fasteners. 12 hrs and they look like new. Don’t use for the painted silver fasteners such as those used on the valve covers.

it would be a good time to replace the fuel lines if you have not already. Oetiker 153 clamps and 7.5mm fuel line.

other questions not yet addressed: I've never heard of the studs having issues on 24V blocks. Should be fine. No preference in head gasket brands. Order from an Alfa parts specialist - it can be the wild Wild West out there.

If you pull the engine you could remove the oil pan and inspect the bottom end. You're getting deep in here now, but if you suspect an issue, that's a surefire way to know. This is how I ended up rebuilding my motor. Check your axial play in the crank while you're in there :), 0.080mm - 0.265mm.

My sincere recommendation is to take your time and not plan on out & back in in a weekend. Obviously it can be done. I tend to make mistakes when in a rush, and I always find more that should get attention while I’m in there.

Cheers,

Karl
 

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Discussion Starter · #9 ·
Thank you everyone and brilliant details, Karl. Really appreciated.
Defo not going to rush this - allowing myself a month if needs be. Planning to change the injectors for the 4 port variety in the process.
Have a pair of new Bosch knock sensors to go in and a new black pipe, along with new seals for it.
Will check the crank axial play too - any tools for this?
Any views on Ajusa head gaskets?
 

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Discussion Starter · #10 ·
How to lower the subframe at the front? It looks like has tabs interlocking with the bodyshell. Unless am mistaken - which is always possible.
 

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How to lower the subframe at the front? It looks like has tabs interlocking with the bodyshell. Unless am mistaken - which is always possible.
Not that I am aware of. Maybe the threaded plates into which you are threading look captive? Just support the subframe mid-span with a jack (I would spread load slightly with some lumber). Unbolt fasteners on both sides, loosen rear fasteners maybe 1/2”, and lower subframe. Need to remove upper motor mount bolt of course.
Careful not to put load on the radiator subframe appendage. That thing is not meant to take any loads and is just held on by a few M6 fasteners.

cheers,

Karl
 

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I had a customer with a 24v who had a t-belt idler lock up and shred the belt. Bent 22 valves before it stopped. I removed the heads with the engine in, a motor / trans. mount or two unbolted, tilting the engine with a floor jack. No problem. It can be done. Cam sprocket can be removed by a judicious strike with a plastic mallet from its rear. Before removing the belt, find TDC on cylinder #1 (a dial indicator in the spark plug hole is best), and then lock the cams in place. The way I do it is I cut a .002" feeler gauge into small pieces, remove a cam cap, insert cut shim. snug cap back into place. This will keep the cam in the exact position. This is important because there are no marks and the cam pulley is mounted on a taper and is not woodruff keyed in position. Just remember to remove the shims!
 

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Discussion Starter · #13 ·
Thanks, Karl. Yes, had a look at it again today and the plate is what I had thought needed to be removed - glad it doesn't and great to know.
Thanks too, Andy. Am aiming not to remove the cam sprockets if can - have heard too many horror stories of them coming loose later, which would be catastrophic.
All the best.
 
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