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Discussion Starter #1 (Edited)
Hallo everybody,
I took a look around in the forum but the searching engine did not allow me finding the infos I need.
The question is very simple: I'd like to install a 164 Super/155 90mm crankshaft in a 2L GTV (115 series), does it need any other modification than shorter rods or pistons? Just to be clear, I have doubts expecially about the oil pump drive/pulley end of the shaft.
If anyone has experience of this swap, or can suggest topics where I can find an answer, it would be very nice.

Many thanks in advance.

Alberto
 

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There will be no problem at the front end with oil pump gear etc. except of the fact you´ll need a different nut size for the pulley, but you have either to distance out the starter or to create a thicker spacer between block and gear box. The reason is that the 90mm crank is shorter at the rear end - flywheel will move closer to the rear end of the block.

You don´t need automatically to use shorter TS rods -depends on the pistons you want to use or compression height. It´s all about calculating and modifying.
 

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No issues when connecting the gearbox (maintaining the Nord block), only that 155 crankshaft needs to be drilled to allocate the bronze spigot bush for the primary gearbox shaft, for the rest is a direct replacement taking into account the 0.75 more of piston protrusion in the chamber, which as said could be useful to actualize the compression ratio more accordingly to modern fuels.
 

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No issues when connecting the gearbox (maintaining the Nord block),
If you put the 90mm crank into a Nord block, of course the gear box will fit. Never denied it. But flywheel will move closer to the rear block end which will cause the starter tooth gear scratching to the flywheel tooth gear. Flywheel flange distance is closer to main bearing center compared to 105/115/116 or 75/90=88.5mm crank.
 

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If you put the 90mm crank into a Nord block, of course the gear box will fit. Never denied it. But flywheel will move closer to the rear block end which will cause the starter tooth gear scratching to the flywheel tooth gear. Flywheel flange distance is closer to main bearing center compared to 105/115/116 or 75/90=88.5mm crank.
No, NORD and 155 crankshaft have EXACTLY the same dimensions (and weight), except that the crank pins are at 45 mm radius in the 155 (90mm stroke) and 44.25mm radius for the NORD (88.5mm stroke), apart the housing for thr spigot bush. I can tell you because I'm involved in a conversion project and I have parts from both engines and have compared them carefully.
 

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No, NORD and 155 crankshaft have EXACTLY the same dimensions (and weight), except that the crank pins are at 45 mm radius in the 155 (90mm stroke) and 44.25mm radius for the NORD (88.5mm stroke), apart the housing for thr spigot bush. I can tell you because I'm involved in a conversion project and I have parts from both engines and have compared them carefully.
THAT´S NOT CORRECT ! I don´t know which cranks you´ve compared; but I can tell you that I´ve built 2 engines with 155 crank and they´re definitely different ! Further differences (beside the rear distance from flange to bearing center):
- 155 crank thread for flywheel bolts is M12x1.25 and not M12x1.5 as with all other 6 hole flywheel flanges in 2000 cranks
- front thread for 36mm nut/pulley is much thicker than at 105/115/116-2 liter cranks so weight can´t be the same !

It´s quite simple: 155 block is not as long as 105 block (do compare this if you like; I know exactly how much shorter it is) is because of the transverse installation in the 155 engine bay. And so is the crank shorter too, matching the shorter block. Do compare ! I do not know exactly if the 164 crank has the same part # like the 155 block so can´t confirm that it´s the same with 164 crank/2nd series. May be your crank is one from 164/1st series - that would confirm both your and my opinion.
 

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Very late Nord cranks share the same flywheel flange thicknes with 2nd series TS.
 

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Very late Nord cranks share the same flywheel flange thicknes with 2nd series TS.
It´s not about thickness but distance. If you mean for example a Spider Series 4 as "very late", it does not have any distance differences to earlier 2000 cranks.
It´s only the 155 crank.
 

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The 155 block is 13mm shorter at the back than the NORD one, BUT while the crank seal in NORD block is housed in the 5th main bearing cap with the cigar seals at the sides, in the 155 block there is a rear cover housing the seal, do you guess what is the thickness of this cover?... yes, 13mm
 

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Discussion Starter #12
THAT´S NOT CORRECT ! I don´t know which cranks you´ve compared; but I can tell you that I´ve built 2 engines with 155 crank and they´re definitely different ! Further differences (beside the rear distance from flange to bearing center):
- 155 crank thread for flywheel bolts is M12x1.25 and not M12x1.5 as with all other 6 hole flywheel flanges in 2000 cranks
- front thread for 36mm nut/pulley is much thicker than at 105/115/116-2 liter cranks so weight can´t be the same !

It´s quite simple: 155 block is not as long as 105 block (do compare this if you like; I know exactly how much shorter it is) is because of the transverse installation in the 155 engine bay. And so is the crank shorter too, matching the shorter block. Do compare ! I do not know exactly if the 164 crank has the same part # like the 155 block so can´t confirm that it´s the same with 164 crank/2nd series. May be your crank is one from 164/1st series - that would confirm both your and my opinion.
very useful data, thanks. I've read somewhere (Kartalamakis' book?) that the 164 block is 6 mm shorter than normal Nord and TS blocks. Did you remember if this measurement is correct? Assuming that the rear Nord block seal works correctly with 155 crank, would you suggest to install a plate between crank and flyweel?

p.s. the 155 has the same code of the 164 Super (2nd series) one; but, of course, 1st and 2nd series 164 have not the same crank.
 

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Discussion Starter #13 (Edited)
The 155 block is 13mm shorter at the back than the NORD one, BUT while the crank seal in NORD block is housed in the 5th main bearing cap with the cigar seals at the sides, in the 155 block there is a rear cover housing the seal, do you guess what is the thickness of this cover?... yes, 13mm
very interesting, but 75 and 1st series 164 have the same stroke but not the same crank. Couldn't it be a clue about having different cases lenght? And from pictures I see that the rear oil seals (that from your measurements shold be on the same distance from the rear bearing) work on an outer part of the crank flange in 155.
 

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The 155 block is 13mm shorter at the back than the NORD one, BUT while the crank seal in NORD block is housed in the 5th main bearing cap with the cigar seals at the sides, in the 155 block there is a rear cover housing the seal, do you guess what is the thickness of this cover?... yes, 13mm
I think you mean something different I do. Do measure the contact surface of the crank where you bolt on the flywheel related to the contact surface at the rear of the block which means the distance you get when you install the gear box. As the gear box stays 105, the block stays 105 but you use a 155 crank which is shorter at the rear end the flywheel will move closer to the rear of the block. And it really does ! This needs mods either in distancing out the starter or using a thicker distance plate between block and gear box. So I suppose there may be differences in 164 type cranks between series 1 & 2 compared to the 155 crank.
If you have flywheel bolt threads sized M12x1.25 you have the latest 155 type crank which IS SHORTER.
 

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Assuming that the rear Nord block seal works correctly with 155 crank, would you suggest to install a plate between crank and flyweel?
Seal works because the flange is wide enough; I would rather distance out the starter. It´s something about 2mm.
 

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Some of the differences in the crankshafts noted in this thread may be detail changes introduced across all of the production engines.

I have a 1993? Motronic [Nord, 80*] crank in front of me and it has 12 x 1.25 flywheel bolt threads. The nose has a larger diameter thread [I think 26 x 1.25] but the sprocket and pulley sections are the same [and weigh the same] as 101-105. Also the seal diameter of the crank is different, 84 rather than 82mm.

And on the other end of the bench is a very late 1600 crank. It also has 12 x 1.25 flywheel bolt threads, and it has an 84mm seal diameter, and it has the 26mm crank nose thread. [Both cranks have tapped oil way plugs].

The two Alfa "75" Twin Spark engines sitting here have 12x1.5 flywheel bolts and 82mm seal diameters.

So the question is: when did all these changes occur?

--Carter
 

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I have a 1993? Motronic [Nord, 80*] crank in front of me and it has 12 x 1.25 flywheel bolt threads. The nose has a larger diameter thread [I think 26 x 1.25] but the sprocket and pulley sections are the same [and weigh the same] as 101-105. Also the seal diameter of the crank is different, 84 rather than 82mm.

And on the other end of the bench is a very late 1600 crank. It also has 12 x 1.25 flywheel bolt threads, and it has an 84mm seal diameter, and it has the 26mm crank nose thread. [Both cranks have tapped oil way plugs].
That´s very correct for the very, very late NORD engines; most of them are still running in these cars so there are not a lot of single engines on the market with these late details. So far I could track the donor cars some engines I´ve built were coming from, the changes for late 115 series started matching launch of Series 4 Spider. May be a little bit earlier with late Series 3, too.
 

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Discussion Starter #19

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Some of the differences in the crankshafts noted in this thread may be detail changes introduced across all of the production engines.

I have a 1993? Motronic [Nord, 80*] crank in front of me and it has 12 x 1.25 flywheel bolt threads. The nose has a larger diameter thread [I think 26 x 1.25] but the sprocket and pulley sections are the same [and weigh the same] as 101-105. Also the seal diameter of the crank is different, 84 rather than 82mm.

And on the other end of the bench is a very late 1600 crank. It also has 12 x 1.25 flywheel bolt threads, and it has an 84mm seal diameter, and it has the 26mm crank nose thread. [Both cranks have tapped oil way plugs].

The two Alfa "75" Twin Spark engines sitting here have 12x1.5 flywheel bolts and 82mm seal diameters.

So the question is: when did all these changes occur?

--Carter
All the information should be available from eper; FIAT ePER :: The FIAT Forum
 
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