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Mixing 1.5 and 1.7 parts for performance..

2517 Views 9 Replies 7 Participants Last post by  Greek
I know that this has been mentioned in various threads but it was not discussed fully. I have a 1.5 Sprint and i want to make some modes. Actually i am thinking of giving a good service on my engine but since i am going to spent some money i am thinking something else.

Can i mix the engine body of a 1.7 8v or 1.7 16v with the heads of a 1.5 in order to keep the mechanical tappets? I know that the 1.5 has low compression and with the use of 1.7 it will be increased without any problem but my question is this.

Is it a direct swap and the 1.5 heads will bolt right in to a 1.7 body? It is quite easy to find a 1.7 engine and i am thinking as a wasy to boost up the car ... Of course i am going to keep the carbs ( 36DRLA) or if i can find 40 IDFs although i have been told that 36DRLA = 40 IDF ....
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I'm a novus when it comes to tearing apart engines and making ones out of the bits, but what you seem to be talking about is pointless. You'd be better off just using an entire 1.7 8v engine if you have it...

Mixing and matching parts is what people do for their race cars not really their everyday road going cars!

yes but i would like to have mechanical tappets....
I don't see anything wrong with using the 8V 1.7 and adding the shim cam housings and then running shims instead of the hydraulic tappets. I don't really know what benefits this mod would have, some people claim it gives you more power, but I am skeptical as to how much or if it would be noticeable.

Things to look out for when doing this mod would be the oil galleries on the heads that feed the hydraulic cam housings and whether or not they would be made redundant by the shim housings, if so oil pressure could be lost.

If you can find a 1.7 16V then I think it would be more worth your while to just swap in the whole unit as it is, rather than mix and match parts from an 8V onto a 16V, that would be a backwards step.

For simplicity Id recommend going the 1.7 8V with some big webers, maybe a porting job while it in bits.

Just remember more horsepower = more dollars...horsepower isn't a cheap comodity.
You can`t swap 95hp engine cam housings/buckets with 105 hp engine or 1.7 engine. Have to use 1.5 105hp cam housing/buckets. Reason is to get more valve lift in 105hp engines and later 1.7 valve stems longer and buckets to go with them (also had solid cams as against split cam lobes with different valve clearance adjustment).
Unless you are serious racing there is nothing wrong with the hydraulic tappets anyway-they will allow you to rev to 7000rpm which is over what you need to rev a std boxer anyway to obtain max power.
Stay with either the 95hp (the best boxer engine) or a std 1.7.

Richard J
The engine is the 105hp not the 95 one and i was told that is a direct bolt. I know that 1.7 is better but there are few other things to consider...

-I can get better price for the 1.7lt without carbs and peripherals (full engine) that just the engine body.
- I dont want to spend a lot of money. My engine feels a bit worn and instead of rebuilding it and make mods on the engine for more power ( ex. 1.7 pistons) it would be better to just put a 1.7 ready so the capacity will be increaced to 1600. I estimate about 200$ for engine and 400$ for the work and small parts. Rebuilding the 1.5 will cost almost the same but with no power gain.
- The car is for everyday use so there is not need for radical mods . Also i like her to look as normal as it can be.
- Also i like the idea to go there where noone has ever been , at least here in Greece.........(ok a joke but i still like it to be among the few who have tried that).
As far as I know, it was made here in Uruguay for a race 33, that went very good, reved to 8000 rpm no problems. As you said, capacity was increased to 1600cc
what i really want to do is mix a 16v with a bored 1500. so you get a 1500 bore it to the right size and then put 1.7 pistons and fit 1.7 heads. in australia this would hold major benifits because the supersprinting categories are: 0-1600 and 1600-2000 etc.. but when these categories are thought through what chance does a 1.7ie sud/sprint/33 have of keeping up with a worked 2L motor'ed car? so, by building a 1600 16v you would get high HP and still be in the little baby (cute fast cars) class.
I have the same idea! but using the full 1.7 16v engine with a 1.5 crank. Gets you 1600, with no boring out and risking thin walls also advantages like oil squirters in the block etc. BTW are you in the NSW Alfa Club? We may have met.
Using 1.7 16v block is much better that 8v because is a litle bit stronger and can hold a lot of pressur. Also another good thing isthat issue with oil circulation but i dont know if you have to use other parts like oil pump , different excaust etc. 8v 1,5 and 1.7 use the same peripherals so the cost drop for that mod.
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