NEED HELP on engine type/size, Previous owner's mods ???? Options

[Str1974]

Guys, I really need your expertise on this. I had purchased a 1974 914 1.8L a while back. The former owner advised me that the engine was not matching. Looks like a previous owner had taken a 1.7 liter case and modified it to be a 1.8L and use a Bosch L-jetronic brain as well as all the air intake/manifold designed for a stock 1.8L. It ran well before I pulled the engine for a new clutch/flywheel etc. project. I had verified that the chassis number matches a 1974 914 and the engine number matches a 1973 1.7L (EA026464).

My real problem now is that I really do not know what exactly was done to the engine to make it a 1.8L. I want to keep the L-jetronic fuel injection system, but if I do want to do a stock engine rebuild, what parts would be for a 1.7L and what would be for a 1.8L. I have researched all over about 1.7L engine mods, but they all seem to be "how to modify a 1.7/1.8 to a 2.0L. Nothing what would have been done to make a 1.7 into a 1.8. an anyone please fill me in on the Possible Mods done to my engine? I have various service records that go back to the mid 80's, but it looks like the 1.7 to 1.8 mod was done prior to that. All those records seem to only mention the car being a 1.8L. I'm afraid to replace parts , not knowing how it became a 1.8L. Please advise, thanks.

[brant]

also... the common upgrade for a 1.8 (or 1.7) when you put larger cylinders in... comes out to 1911

so not really a 1.8 technically.

you would put stock cylinders and pistons in to make it a 1.8 again
or you could keep the larger displacement as it is likely a more powerful engine

you would also want to see which heads are on yours when it is torn apart
if they are 1.7 heads then I believe they would have slightly smaller valves than a 1.8 stock motor would have.

the Air Fuel Ratio should be measured on a running engine to tell you whether your mixture is adjusted to handle a larger placement or whether you need to adjust the fuel injection system still

[Str1974]

also... the common upgrade for a 1.8 (or 1.7) when you put larger cylinders in... comes out to 1911

so not really a 1.8 technically.

you would put stock cylinders and pistons in to make it a 1.8 again
or you could keep the larger displacement as it is likely a more powerful engine

you would also want to see which heads are on yours when it is torn apart
if they are 1.7 heads then I believe they would have slightly smaller valves than a 1.8 stock motor would have.

the Air Fuel Ratio should be measured on a running engine to tell you whether your mixture is adjusted to handle a larger placement or whether you need to adjust the fuel injection system still

I keep thinking that if the fuel injection is L-Jetronic (computer brain has L-jet serial numbers), would the heads not have to be 1.8 in order for a L-jet intake manifold to work with that type of Bosch EFI?

[brant]

also... the common upgrade for a 1.8 (or 1.7) when you put larger cylinders in... comes out to 1911

so not really a 1.8 technically.

you would put stock cylinders and pistons in to make it a 1.8 again
or you could keep the larger displacement as it is likely a more powerful engine

you would also want to see which heads are on yours when it is torn apart
if they are 1.7 heads then I believe they would have slightly smaller valves than a 1.8 stock motor would have.

the Air Fuel Ratio should be measured on a running engine to tell you whether your mixture is adjusted to handle a larger placement or whether you need to adjust the fuel injection system still

I keep thinking that if the fuel injection is L-Jetronic (computer brain has L-jet serial numbers), would the heads not have to be 1.8 in order for a L-jet intake manifold to work with that type of Bosch EFI?

nope.. heads don't care about induction
you can run any head... but the 1.7 head has the smallest valves.
but you can run L-jet on a 1.7/1.8/2.0 or 2056

bigger valves help move more air.. more HP
the 2.0 heads have the best flow and best design

injection fuel flow needs to match the displacement to get to the correct AFR
so many people will measure the AFR and adjust their injection system to accommodate their need on a particular engine....