815 coupe restoration

[Kevinlincs]

My 1.8 heads are looking like needing work, I feel the valve guides are outside specification but awaiting a small bore gauge to measure them before ordering a set of guides are they aren't as cheap as modern stuff!
Occurred to me that I had 2 pairs of spare heads that came with the car so maybe they would be a better proposition to use as the 1800 heads also have a fair amount of pitting but that should be able to be skimmed out, something I'd do anyway.
But on digging out the spare heads it was obvious they must be from the 2litre cars, way bigger valves and marginally bigger combustion chamber diameter. So no good.......or are they?
Has anyone used these heads on 1800 bottom ends?
Is it even possible?
I've not checked the pistons to see if they are pocketed on the 2000 cars to allow clearance for the bigger valves, obviously there is a slight difference in head face where the gasket fire ring will sit but only 88mm to 89mm so that shouldn't be an issue.
Valve lift would be the same as I'd still use the original cams.

Has anyone tried it?
Would it work?
Just the spare heads look way better, guides feel good but not yet measured...
Should flow much better and therefore produce slightly better power, intake throats for example are approximately 5mm larger than on the 1800..

[lancianut666]

Question is how do they get the 2 litres... bore bigger or stroke longer? from the pics it looks like a bigger bore so the next question is could you swap the barrels like a beetle to ger 2 litres?
Clarkey

[Kevinlincs]

They used a 80mm vs 74mm stroke as well as increasing the bore by 1mm to 89mm.
I don't have any 2L barrels and pistons but my 1.8s are in great condition so I will stick wih those.
In all probability I will most likely stick with stock heads, simpler all round.
Just looking at the much larger (appx 5mm) valves and throats it looked like the 2L heads would flow better.
Never going to be built as a speed machine in any case and stock is always my go to for keeping it simple, guess I have to much time on my hands thinking silly thoughts 

[Kevinlincs]

I asked a well trusted and knowledgable guy if he knew of anyone that had used 2000 heads on the 1800 engine and he knew of two seperate cases where the heads had been used with great success, it seems a swap to use the much better condition and functional 2000 heads is my best way forward as these spare heads are in much better condition all round.

[lancianut666]

I reckon some extra torque would be in order always very useful...a trip to a rolling road when the car is up and running might prove useful as well.
Clarkey

[Kevinlincs]

Built a crude but effective frame tonight so I can build the engine up on my engine stand.
Not as simple as a normal in lne engine as the crankcase is in two halves, the workshop manual shows a stand bolted to one side casing which I've replicated, so should be able to follow the rebuild process in the same way.

[Kevinlincs]

Nice little tool arrived this week to allow me to measure accurately the valve guides for wear, only really assessed wear before by wiggling side to side then sending to the machine shop if they felt loose.
Now I can measure them accurately to closer than 0.01mm with a micrometer and the small bore gauge set.
Upshot is that the valve stem to guide clearance is within spec. Maximum wear is set at 0.12mm on the exhaust side and they are between 0.04mm to 0.06mm so well within, inlet side similarly at around half wear limit which is slightly finer tolerance wise.
I've set the heads down in the parts washer to soak now so will clean and send for skimming this week hopefully.

[Kevinlincs]

Well, a change of plan is in place yet again!
The heads were left in soak overnight to free up the congealed old coolant in the waterways but it was still pretty solid with old gunk, an hour or so of scraping and flushing got it somewhere near to clear but as the space above the combustion chamber is also hollowed out it was tricky to get it all out so a further soak and a blast with the pressure washer would hopefully do the trick.  Leaving anything in there would eventually cause issues as it would no doubt flow around the cooling system and block somewhere critical.
There was also the realisation that the pitting on the head face was much worse now it had been cleaned out, way more than any refacing would clean out as some pockets of corrosion were 3.5mm deep!
Time to think again.

On looking again at the 2000 heads I have it was obvious they were in much better condition and would only require a precautionary skim to ensure it being level rather than to try and get rid of any corrosion. The waterways were dusty but free of any coolant residue, just a bit of powdering from the alloy. A quick clean in the parts washer and later pressure wash would be more than enough.
Time to strip the valves out and make sure the guides and valves are within spec, which they are!

Another deciding factor came as a great but very welcome surprise, the inlet valves have an oil seal whereas the 1800 heads have no stem seals on either valves, this bonus will help greatly with blue smoke out of the exhaust.
Theory being that oil is sucked down the valve guide of the inlet valve when on the intake stroke, having a stem seal will stop that.

As can be seen below, the 2000 heads are in vastly better condition.

[Kevinlincs]

The other bonus is I will effectively have a big valve head conversion which should pep it up a little and let it breathe easier.
The below pictures are of the inlet valves from the 1800 and 2000 to show just how much bigger they are on the 2000, approximately 5mm bigger just looking with a tape measure.
You'll also notice a massive difference in carbon build up on the stem, another strong confirmation of the advantages of having stem seals.
I'll pressure wash the heads tomorrow at work and call the machinist who is very good and local to me so there's every hope of them getting a quick skim and back to me in time for Christmas.
As the engine gasket set won't have the valve stem seals being a 1.8 kit I had a look through my stash of unused new gaskets from various tasks and I found a new set in a bag, probably from the integrale or even Alfa twin spark engine but handily they are a perfect fit, on the guide and the right size for the valve.
The other issue I wondered about was with the bigger valves would the 2000 have pockets in the pistons to allow them to open. Amongst the spares we're a set of pistons! Very handy to have them to hand, no pockets in the crown so it confirms what I have been told, they will go on the 1.8 without issue.

So that's decided,  it will have a big valve head conversion!