Technical 1978 124 Project

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Technical 1978 124 Project

Yes a few more passes with the hone, it looks like there's still untouched areas and then it could use a finer finish..is there much of a ridge at the top? You might be able to borrow a ridge reamer from the local auto parts store...
 
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Finally today - I got a good look at the front engine cover (yellow) and there is a sticker saying "california" which may mean that this motor had additional emissions controls on it?? In any case, here is a video of my survey before I took the radiator out. I'm wondering if anyone has any thoughts on the wiring anomalies (?) I found....


I also have a 1978 California model, and I can tell you that a lot of your "loose" wires are from smog stuff that was removed. Look under your distributor cap... someone might have installed a Pertronix ignition module, and that's the red wire running to your coil. But if that's true, it should also have a black wire going to the negative side of the coil.
 
I believe ring gap is measured with a feeler guage while in the cylinder?
Yes you can measure the ring gap like this. The ring needs to be at the respective height in the bore
The bores can go oval in the direction of thrust on the conrod. You will need a micrometer bore guage for this. There were a couple of used sets on for about £25 recently
 
I also have a 1978 California model, and I can tell you that a lot of your "loose" wires are from smog stuff that was removed. Look under your distributor cap... someone might have installed a Pertronix ignition module, and that's the red wire running to your coil. But if that's true, it should also have a black wire going to the negative side of the coil.
Very interesting. Here is the top of my distributor - thoughts?
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Ya, give that one a gold watch and retire it! Ebay might be a good place to shop for a used one from a private party...if your going to buy new eBay is not the place, new fiat parts seem marked up compared to the fiat company's we know...
 
Ya, give that one a gold watch and retire it! Ebay might be a good place to shop for a used one from a private party...if your going to buy new eBay is not the place, new fiat parts seem marked up compared to the fiat company's we know...
A guy n texas has just listed a car hes breaking maybe thats of some use to you?
 
Just checking in to see how your doing with your spider? Did you get started with your welding? There's a guy on ebay that's pretty much the biggest used parts seller, his user name is something like volvo80, he has a couple of parts cars he offers to cut parts from...you might ask if he has any good floor sections? Getting usable floor pieces might save you some time doing patch panels....just a thought! Hope all is going well!
 
Just checking in to see how your doing with your spider? Did you get started with your welding? There's a guy on ebay that's pretty much the biggest used parts seller, his user name is something like volvo80, he has a couple of parts cars he offers to cut parts from...you might ask if he has any good floor sections? Getting usable floor pieces might save you some time doing patch panels....just a thought! Hope all is going well!
Thanks, Slotman - I appreciate you checking. Have had a family medical event that has taken me out for a while. Just got back into the shop today for a bit. Was seeking to clean the rings on the pistons and when I was removing them, nearly half of them broke! I think the engine (which was reported to have been running hot) was in a very unhappy place. I'm going to make it happy, I think, and make the plunge to buy new pistons and rings and just move on with the rebuild. Eventually I get back to the body, but owing to the $$ spent on motor, I'll definitely be looking for the most economical approaches to fixing the floor pan (and anything else!).
 
Thanks, Slotman - I appreciate you checking. Have had a family medical event that has taken me out for a while. Just got back into the shop today for a bit. Was seeking to clean the rings on the pistons and when I was removing them, nearly half of them broke! I think the engine (which was reported to have been running hot) was in a very unhappy place. I'm going to make it happy, I think, and make the plunge to buy new pistons and rings and just move on with the rebuild. Eventually I get back to the body, but owing to the $$ spent on motor, I'll definitely be looking for the most economical approaches to fixing the floor pan (and anything else!).
If you buy new pistons and you have 84mm bores try ti find some lancia beta 1600, higher compression (more power) for similar price.
 
--------------------------------------------------------------------------------------------------- Was seeking to clean the rings on the pistons and when I was removing them, nearly half of them broke! I think the engine (which was reported to have been running hot) was in a very unhappy place. I'm going to make it happy, I think, and make the plunge to buy new pistons and rings and just move on with the rebuild. Eventually I get back to the body, but owing to the $$ spent on motor, I'll definitely be looking for the most economical approaches to fixing the floor pan (and anything else!).
I've been looking back over your pics of your engine as you disassembled it. I always look carefully at what I find when stripping an engine and try to figure out as best as I can what may have happened in the past to leave such 'marks' or damage. I suspect that your engine was 'worked on' and then covered not too many miles before you bought the car.

You mentioned in an early post that you suspected it might have a cracked head and it wasn't running. you found the cooling system badly choked with rusty debris (so presumably no anti-freeze had been used), missing studs on exhaust manifold (iirc), an incorrect crank pulley nut had been installed, and signs of foreign debris damage to the piston crown and corresponding area or cylinder head located within the cylinder. When I looked at your pic of No. 4 piston, I initially thought you had done an excellent job of cleaning it, but then decided that it was too clean, no blow-by type of staining on the piston skirt, no wear marks on the piston skirt and the surface finish on the piston skirt is not as smooth as on original Fiat pistons, nor do I see any of the original piston crown markings found on Fiat pistons.

My conclusion is that your engine had a problem and sustained damage resulting in a quick/cheap repair. I'm wondering if piston no.4 was replaced or possibly all new pistons were fitted (it is possible to buy single pistons and indeed single piston ring sets), you haven't said if the cylinder bores are still standard (84mm?) size or have been rebored?

It's very easy to break pistons rings when trying to remove them (they're usually cast iron so quite fragile) even when using the correct piston ring pliers.
Before removing rings, it's useful to make some measurements using simple feeler gauges to check for ring side clearance (i.e. up and down) in the piston ring grooves to get an initial indication of piston/ring wear. It's important to mark the top of each ring so that it can be refitted the correct way up (there are usually marks indicating the top surface on new rings but these can be worn away in use - the sealing edge of the compression rings is very carefully designed, some have a taper of only a few degrees - so indiscernible by eye, hence the need for 'top' markings, 2nd compression rings often have a tiny undercut that acts as an additional oil scraper, again important that it's fitted the correct way up. Many people think that the 'springiness' of the ring is what does the sealing - that's only part of the equation, gas pressure also acts behind the ring pushing it against the cyl. bore.
When examining pistons with a view to possibly re-using them, one thing often overlooked is if the top and bottom of the ring grooves are still parallel -
the top surface of the ring groove wears, usually in a tapered shape, the top ring groove can be badly affected, particularly on engines that have a choke (i.e. carb models) and do a lot of short runs in cold climates. The top piston ring can wear so that it has a hollowed-out shape, normal thickness at the outside edge but hollowed out further in, inside the piston ring groove - this is bad news, the ring is no longer being correctly supported, it flops up and down in it's groove each time the piston changes direction and also flexes, altering the angle between it's sealing face and the cyl. bore - it also can result in the ring shattering into small pieces particularly on engines that are revved hard from cold - the shattered ring results in poor compression, and the bits of broken piston ring can work their way past the top ring land (the part of the piston above the top ring groove) into the combustion chamber and get caught between the piston crown and the cylinder head resulting in strange 'pock marks' - similar to your engine damage in no. 4 cylinder...
Some of the marks on your piston remind me of the damage caused by the engine ingesting a small washer, typically a 6mm Belleville type spring washer that Fiat use in some areas. Sometimes the errant washer or the bits of broken piston ring will be ejected out the exhaust port if the engine is revved-up.... How might a washer get into a cylinder? possibly dropped down the carb choke while the air filter is off - it's important to check that nothing has accidentally entered either the intake or exhaust manifolds before refitting them to an engine.

I've stripped many older Fiat engines and have often found the top piston rings shattered into pieces. Have also found the oil control rings and their oil drainage groves/holes completely blocked by sludge/gum rendering the oil control rings unable to do their work....

As regards the current state of your engine...
It's possible you don't actually need new pistons, if they were replaced in the past.
I thought you deglazed the cyl. bores using stones with too coarse a grit. When simply deglazing a bore before fitting new rings, I prefer to use a 'ball-hone' type of tool (brush-style hone), it's a lot gentler. The flat stone type of hone is fine but I wouldn't attempt to remove the wear ridge near the top of the cylinder, concentrating the tool in this region can result in a tapered cylinder. Not a great fan of 'ridge-removal'l tools either, they remove material that locates/supports the piston at tdc.- I prefer to use 'ridge-dodger' pistons rings instead. I don't like removing material unnecessarily from a cylinder, it's easy to take 1 or 2 thou. from a cylinder when honing to remove all marks/signs of wear, result is your pistons now have 2 thou more room to rattle around in (plus piston wobble when it changes direction, altering the angle between the rings and the bore).

If it was my engine, I'd carefully check over the pistons with a view to re-using them, paying particular attention to signs of damage, their fit in their cyl. bore and possible ring groove wear. And just but new rings (preferably ridge-dodger type if available).

What happened to your engine originally?
I suspect an overheating issue. I mentioned in an earlier post about some tips as regards cyl. block preparation. I'd now recommend you remove the metal plate at the rear of the cylinder block that covers the coolant jacket (iirc, it's held on by 6 x 10mm headed bolts and will likely have to be prised off, I suspect Fiat used a gasket adhesive originally. Also remove the 4 (or 5?) core (frost) plugs in the coolant jacket and use a stiff wire with a 90* bend on the end to loosen/rake out any remaining rusty debris around the cylinders - I suspect you'll find a lot of rusty debris behind the metal cover plate and the core plugs may be almost rusted through, given the state of your engine cooling system. I note you have used a pressure washer and got a lot of rusty gunk out but that space at the rear of the coolant jacket (under the cover plate) may still be clogged up and could result in a 'hot-spot' that could cause problems in future. (many people, even professional Mechanics don't bother and think it'll be ok...).
 
If you buy new pistons and you have 84mm bores try ti find some lancia beta 1600, higher compression (more power) for similar price.
There are high-compression piston sets available in the U.S. (from the usual suspects, see below) at reasonable cost but I'd caution about going too-high in C.R. given the state of what passes for gasoline nowadays.

Screenshot_13-4-2025_221418_www.vickauto.com.jpeg




Also would caution about using so-called 'pop-up' pistons to raise compression ratio, you'd need to take some careful measurements and do the necessary calculations before opting for these pistons, plus be aware that these pistons types do not use standard Fiat size rings (it says so in the webpage)

I don't see much point in fitting new high-compression pistons to worn cylinder bores, so a re-bore and oversize pistons is then needed, resulting in increased cost (i.e cost of pistons + cost of machining work), which then introduces the possibility of 'sloppy' machining work being carried out. I've often read of people asking for suggestions re where they might find 'a good machine shop' in their area, I haven't seen many responses. I've concluded that it's the person (especially their attitude) doing the machining that determines whether the outcome is good or otherwise, not the machine shop (they're all equipped more or less equally). I've had some bad experiences...
 
There are high-compression piston sets available in the U.S. (from the usual suspects, see below) at reasonable cost but I'd caution about going too-high in C.R. given the state of what passes for gasoline nowadays.

View attachment 464966



Also would caution about using so-called 'pop-up' pistons to raise compression ratio, you'd need to take some careful measurements and do the necessary calculations before opting for these pistons, plus be aware that these pistons types do not use standard Fiat size rings (it says so in the webpage)

I don't see much point in fitting new high-compression pistons to worn cylinder bores, so a re-bore and oversize pistons is then needed, resulting in increased cost (i.e cost of pistons + cost of machining work), which then introduces the possibility of 'sloppy' machining work being carried out. I've often read of people asking for suggestions re where they might find 'a good machine shop' in their area, I haven't seen many responses. I've concluded that it's the person (especially their attitude) doing the machining that determines whether the outcome is good or otherwise, not the machine shop (they're all equipped more or less equally). I've had some bad experiences...
All very good points!
I had the bores honed by a quality engine shop
I used Lancia pistons as I knew they would fit as they are a standard part
You still need to gap the rings to the bores
This set uo gives around 9.8:1 CR
It was oart of a controlled and measured full engine rebuild and I run the car on 100 octane, usually Texaco

Generally if you replace old and worn engine oarts it needs to be a full engine rebuild to see any benefit
It also depends how much you want to spend and what you want to achieve. All the components need to be compatible and consistent with your objectives

There is no point fitting wild cams with peak power at 7500 rpm with reused valve springs, cast pistons and a non tuftrided crank (std on some models). The Lancia engines also have higher pressure oil pumps which can be modified to fit

If you want to investigate this route Guy Crofts excellent book lays out the necessary detail to get you started.

I built a reliable torquey 150ho 2lit engine using standard Fiat and Lancia oarts without spending a fortune but it did take a while to get the oarts together nearly 15 years ago!
 
@Slotman, @Twink80 and @124BC1 - thanks all for your consistent help and patience. It’s been slow, but I am taking note of all of your advice. Here are some updates:
- Cylinder honing: I got varying info on the grit to use, and settled on 220. I did NOT hone all of the top ridge away, and kept everything oiled as I went. I believe they are ready.
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- Pistons: loved reading about the possible causes for piston crown and head damage. I was gifted with the “complete” set of maintenance papers going back to the original sale docs and then consistent maintenance starting in the 90’s. I don’t think all the history is there; however I did not find any bills or documents pointing to engine rebuilds. My personal theory is that, with the second owner, she found “a guy” to work on the car. Stuff fell in the well for #4 spark plug, and went in as the spark plug came out. After MUCH deliberation and reexamination I’ve opted to buy new stock 84mm pistons with rings installed. I kinda don’t want to pull the engine again. And I’m not going for performance upgrades - I just want it to run well and reliably (F.I.A.T. Notwithstanding)
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- Cylinder head: I took your advice and took my time. Razor blade scraper, Dremel tool with various bits, cleaner sprays. Some nice music. A few cups of coffee. I believe it is ready, although my initial test of the new valves has me worried that 3 of the guides have the tiniest bit of play that might be worth addressing. I also want to use the existing stock cams as they look good, spin freely and have no play.
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- Block water jacket / freeze plugs: I will check the end of the block and remove anything there to completely clean the gunk out. The pressure washer did a super job (also on the head). The freeze plugs just had some surface rust (very mild) so I opted to treat that and paint. I will check though. Last pic for today:
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