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Discussion Starter #1
All looking for your advise and thoughts. I have a build restriction that requires i use a 1.5 block and can not use twin cam heads.

I have built a first version which is pretty basic,

(1) mech heads (ported & Polished), larger 1.7 valves
(2) fast road cam
(3) mech lifters
(4) standard bottom end
(5) lightened flywheel
(6) 40 MM carbs
(7) x over manifold

I am lookin to build a version two and am wondering what people would thinkk of the following configuration

(1) 145 1.6 heads (same bore as 1.5 block.) mech cam carrier valves etc as above.
(2) 145 1.6 crank and pistons
(3) 1.5 block
(4) a little wilder cam (skimmed head to raise CR)
(5) lightened flywheel
(6) 40 MM carbs
(7) x over manifold

On inital investigations this configuration looks like it would work?, or do you think it is better to continue to work on bottom end of version one and lighten stuff to increase RPM. the goal is is strong, simple, repairable reliable and reasonable HP, for a classic race car.

look forward to your thoughts?
 

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Can the block be bored?

1.6 can be got using either the 87mm pistons of the 1.7 and the 1.5 crank or use the 84mm pistons of the 1.5 and the 1.7 crank.

What HP are you getting from your current setup?

rsfruitbat
 

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Discussion Starter #4
Can the block be bored?

1.6 can be got using either the 87mm pistons of the 1.7 and the 1.5 crank or use the 84mm pistons of the 1.5 and the 1.7 crank.

What HP are you getting from your current setup?

rsfruitbat
Not sure on the HP at moment, i do know my total dry weight is <700kg I will know once it has been on the rolling road in the next month. I am trying to setup a second engine as a spare. I dont really want to touch the block if at all possible as it is already honed and ready to go on a 84mm bore.
The primary reason i am asking is most people seem to get 1.6 from increasing the bore either through
- 1.7 block
- increasing capaicity in 1.5 block
I might be being a little stupid but i dont understnad why it would not be just as easy to use 145 parts for this mod?.

regards

alan
 

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You can use 145 parts. I dont know of a reason you cant. Alfa just copied what motorsport guys were doing. 1.6 is a common class break
I would suspect that a 145 1.6 crank may have the nose for air-con, power steering etc.
If you can get a 1.6 boxer engine then a lot of the machining etc will have been done. Did Alfa do a 1.6 8V? If they did was it chambered heads or pistons?
From what you have said you want to use older style heads. Are they chambered or flat as it will have to match what comes off the 145 engine.

rsfruitbat
 

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Discussion Starter #6
You can use 145 parts. I dont know of a reason you cant. Alfa just copied what motorsport guys were doing. 1.6 is a common class break
I would suspect that a 145 1.6 crank may have the nose for air-con, power steering etc.
If you can get a 1.6 boxer engine then a lot of the machining etc will have been done. Did Alfa do a 1.6 8V? If they did was it chambered heads or pistons?
From what you have said you want to use older style heads. Are they chambered or flat as it will have to match what comes off the 145 engine.

rsfruitbat
(1) it seems a 1.6 8v was made,
(2) it seems to have chambered heads, though as yet i have not been able to source a view of the pistons from this.
(30 the block from the 1.6 looks to be the same as the 1.5,
(4) just a longer stroke(so i guess this is actually a 1.7 crank).
(5) i had a thought that the cam carriers might be able to be moved across to the 1.6 chambered heads from the 1.5 single lobe carier ( i need to try this though?)

I am assuming a couple of bits, but i think i will crack on and try it, the only missing part at the moment is 1.6 pistons so I will start the search.

What i guess this would give a setup with 1600cc class max, no major engine work and all replaceable parts
 
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Have nothing major to add apart from they did make a 1.6 8v as I have one in the spare room! Its hydraulic tappets with injection, came out of a '95 145. It looks exactly the same as the 1.3 carb engine it will be replacing in my 33.
 

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modded 1.5 is what i'm looking into too mate..

Think i'm gonna go with a 1500 block, and 1.7 crank to get the 1.6 thing going on.

had heard that the camshaft and carriers from a 105hp engine can be transferred to other heads ( no-one has confirmed this tho), so what about the 1.6l block from the 145 with cams and carriers from a 105hp 1500?

If you gonna strip the bottom end, then i guess its worth getting the crank and stuff lightened, balanced and polished etc.. and almost certainly worth getting the block skimmed to mek sure its proper flat.

If the 145 engine uses flat heads, then earlier 95hp heads would bolt straight on right?
If they are chambered, then the later 105hp heads would bolt straight on.. Looking at the manual(s), there are a few variations in combustion chamber volume, so it may be possible that using the early flat heads on the 145 block would give a healthy increase in compression.

However, i once owned a 1.5 IE, and it seemed to be a fair bit pokier than it's stated 109hp.. :rolleyes:
 

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I,m going down the 1600 route too! 1.7 block with 1.5 crank! will give 1600cc also but shorter stroke having to block skimmed to allow for the shorter stroke! you could use the 1.5 heads with your combination but check what the compression ratio will be, because with the 1.7 crank the pistons will be flush with the block surface and the 1.5 heads have no combustion chamber to speak of! may require some machine work to the pistons to lower the compression!! :rolleyes:
 

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Discussion Starter #12
had heard that the camshaft and carriers from a 105hp engine can be transferred to other heads ( no-one has confirmed this tho), so what about the 1.6l block from the 145 with cams and carriers from a 105hp 1500?
Yes i have done this before i have not seen any issues so far, though think there might be a problem if the head is hydralic?. not tested this

If the 145 engine uses flat heads, then earlier 95hp heads would bolt straight on right?
If they are chambered, then the later 105hp heads would bolt straight on.. Looking at the manual(s), there are a few variations in combustion chamber volume, so it may be possible that using the early flat heads on the 145 block would give a healthy increase in compression.:
The 145 heads that i have seen are not flatheads so i guess it should work

I,m going down the 1600 route too! 1.7 block with 1.5 crank! will give 1600cc also but shorter stroke having to block skimmed to allow for the shorter stroke! you could use the 1.5 heads with your combination but check what the compression ratio will be, because with the 1.7 crank the pistons will be flush with the block surface and the 1.5 heads have no combustion chamber to speak of! may require some machine work to the pistons to lower the compression!! :rolleyes:
I really wish i could go this way as it looks much more like a simple setup. reg's won't let me though, i understand the princples of stroke lenght but boxer engines dont every seem to to ever reach even close to a 1to1 ratio, that was why i was wondering why no one strokes them, even a 1.6 boxer is still a very short stroke engine. porsche seem to be able to use a longer relitive stoke and still get high RPM.

I'd be keen to hear how you guys get on, i am starting this build in the next 6 weeks, so will keep all updated.
 

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You said in your spec 2 engine that you plan on skimming the heads to increase c/r, you need to skim the block to do this properly, skimming the head only brings the valves closer to the pistons and alters the shape of the combustion chamber, the c/r is determined by the piston at tdc and at its max bottom stroke, the further up the bore the better the squish
 
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