Fiat 1438cc TC - Condition of Block & Head surface
Posted: May 2nd, 2017, 9:47 pm
Hi,
I have recently purchased a Fiat 124 AC Sport Coupe from 1967. The car will get a introduction in the Readers Cars section in due time.
The question is somewhat long as I feel the circumstances are important to the problem.
However, the quick version:
- Is the block surface likely to seal with the shown corrosion around the water jackets (see pictures)
- What could be the origin of metal build up on the cylinder head in the quench area (see pictures)
- Is the head likely going to seal, provided it is straight and the ridges are taken off, considering the shown corrosion around the water jackets (pictures)
Now for the long version:
Upon purchase the engine ran fine and continued to do so for the first 300km of the
journey home. After that it started to develop severe overheating issues. Due to the lack
of other symptoms (No blue or white smoke, no appareant oil-consumption, no water consumption when not boiling over)
I nursed the car the remainder of the way home. Upon inspection at home
cylinder 1 showed zero compression on the tester -> The head had to come off anyway.
There is no clearly/visibly broken part (Headgasket, Valve, Piston-Rings) that could be responsible
for the lack of compression. However there are a few places where there is corrosion.
As the head has to go to the machine shop anyway to check straightness (I do not own a long enough straight edge),
I decided to have it cleaned and will rebuild it to prevent future oilleaks or other problems.
Technical Specifications:
- Fiat 1438cc Twin Cam engine, 1967, ~120'000 km
- Uneven Bore spacing (1&2, 3&4 ~7mm, 2&3 ~10mm)
- Engine is stock
- Valve lash as measured (In/Ex) [mm]: 1: 0.35/0.4, 2: 0.35/0.35, 3: 0.35/0.4, 4: 0.35/0.4
Condition:
Block:
- Original crosshatching at top of the bore, no deep scoring
- Corrosion around some water ways, ~2mm deep & ~5mm into the gasket surface (see pictures)
- Rust under the intake between 2&3 -> likely some coolant got out at some point (see pictures)
=> I would like to leave the block in the car and not rebuild it. Do you think the
water jackets are a problem with sealing?
Head Gasket:
- No obvious damage
- Was only doweled at 2 diagonal points (Is this problematic?)
- Slight signs of coolant around corroded water jackets.
Head:
- Cylinder 1 has more carbon build up in the quench area then the rest
- 2 metal ridges/buildups just inside the firing ring of the gasket on cylinder 1 (see pictures)
- Corrosion around some water jackets (see pictures)
- Carbon build up in chambers, both intake and exhaust and the spark plug (I suspect running to rich)
- Very slight pitting near cylinder 1 intake valve/head gasket, possibly from water entering the chamber.
- Valve seats had carbon build up as well
-> My conclusion would be that the head either warped or wasn't seated right from the beginning (ridges), leading
to leakage around cylinder 1.
=> Apart from refacing if necessary (at least taking of the ridges) do you see another problem with sealing?
Are the water jackets too far corroded to be sealed properly? For the valves is simply re-lapping them enough?
Thank you for your help,
Nils Wenzler
I have recently purchased a Fiat 124 AC Sport Coupe from 1967. The car will get a introduction in the Readers Cars section in due time.
The question is somewhat long as I feel the circumstances are important to the problem.
However, the quick version:
- Is the block surface likely to seal with the shown corrosion around the water jackets (see pictures)
- What could be the origin of metal build up on the cylinder head in the quench area (see pictures)
- Is the head likely going to seal, provided it is straight and the ridges are taken off, considering the shown corrosion around the water jackets (pictures)
Now for the long version:
Upon purchase the engine ran fine and continued to do so for the first 300km of the
journey home. After that it started to develop severe overheating issues. Due to the lack
of other symptoms (No blue or white smoke, no appareant oil-consumption, no water consumption when not boiling over)
I nursed the car the remainder of the way home. Upon inspection at home
cylinder 1 showed zero compression on the tester -> The head had to come off anyway.
There is no clearly/visibly broken part (Headgasket, Valve, Piston-Rings) that could be responsible
for the lack of compression. However there are a few places where there is corrosion.
As the head has to go to the machine shop anyway to check straightness (I do not own a long enough straight edge),
I decided to have it cleaned and will rebuild it to prevent future oilleaks or other problems.
Technical Specifications:
- Fiat 1438cc Twin Cam engine, 1967, ~120'000 km
- Uneven Bore spacing (1&2, 3&4 ~7mm, 2&3 ~10mm)
- Engine is stock
- Valve lash as measured (In/Ex) [mm]: 1: 0.35/0.4, 2: 0.35/0.35, 3: 0.35/0.4, 4: 0.35/0.4
Condition:
Block:
- Original crosshatching at top of the bore, no deep scoring
- Corrosion around some water ways, ~2mm deep & ~5mm into the gasket surface (see pictures)
- Rust under the intake between 2&3 -> likely some coolant got out at some point (see pictures)
=> I would like to leave the block in the car and not rebuild it. Do you think the
water jackets are a problem with sealing?
Head Gasket:
- No obvious damage
- Was only doweled at 2 diagonal points (Is this problematic?)
- Slight signs of coolant around corroded water jackets.
Head:
- Cylinder 1 has more carbon build up in the quench area then the rest
- 2 metal ridges/buildups just inside the firing ring of the gasket on cylinder 1 (see pictures)
- Corrosion around some water jackets (see pictures)
- Carbon build up in chambers, both intake and exhaust and the spark plug (I suspect running to rich)
- Very slight pitting near cylinder 1 intake valve/head gasket, possibly from water entering the chamber.
- Valve seats had carbon build up as well
-> My conclusion would be that the head either warped or wasn't seated right from the beginning (ridges), leading
to leakage around cylinder 1.
=> Apart from refacing if necessary (at least taking of the ridges) do you see another problem with sealing?
Are the water jackets too far corroded to be sealed properly? For the valves is simply re-lapping them enough?
Thank you for your help,
Nils Wenzler