wot crank will fit with 90.5 b&ps( not stroker)
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i've got a 74mm crank with 90.5's which gives 1955, lovely.
Minimal minimal clearancing, but you will have to alter some of your parts.
If you dont want to alter anything use your stock crank, or if you plan to rev it a bit higher, a counterweighted stock crank would be advisable- £179 for a welded or £210 for a forged CB item (speedshop). Even the slightly longer stoke makes a nice difference to the drive
Minimal minimal clearancing, but you will have to alter some of your parts.
If you dont want to alter anything use your stock crank, or if you plan to rev it a bit higher, a counterweighted stock crank would be advisable- £179 for a welded or £210 for a forged CB item (speedshop). Even the slightly longer stoke makes a nice difference to the drive
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20,431 Posts
I have the same as doobyscoo and can confirm that it runs real nice, and I think it is a great combo as the bore/stroke ratio is kept somewhere standard and the engine does not get wildly over square as just increasing bore. As the $ is in the toilet at the moment this is the time to get a new crank. The $ WILL increase in 6 months.
I think when you say 'do not want a stroker' I guess you mean you do not want a large increase in crank throw, because as everyone else has pointed out, a crank throw greater than 69 is a stroker crank. It is generally accepted that a 74mm crank will go in without any or very minimal clearancing or change to pistons rods etc.
76mm might also be possible, but as each case is ifferent you might nee dto get working. After that you will need case work and different rods and probably pistons to keep angular acceleration and clearance at the BDC.
I think when you say 'do not want a stroker' I guess you mean you do not want a large increase in crank throw, because as everyone else has pointed out, a crank throw greater than 69 is a stroker crank. It is generally accepted that a 74mm crank will go in without any or very minimal clearancing or change to pistons rods etc.
76mm might also be possible, but as each case is ifferent you might nee dto get working. After that you will need case work and different rods and probably pistons to keep angular acceleration and clearance at the BDC.
...
yeah cheers the last bloke on here was helpful
i know that its a stroker if you increase the crank but i meant that i want to keep the 5.5 rods and not go for the longer stroke b&ps..
not change the deck height...
so am i thinkin that i can put a 74 crank with 5.5 rods and use the standard 90.5 b&ps..
where do i have to take the case lining out to clear the crank??
just the top of it???
cheers steve
yeah cheers the last bloke on here was helpful
i know that its a stroker if you increase the crank but i meant that i want to keep the 5.5 rods and not go for the longer stroke b&ps..
not change the deck height...
so am i thinkin that i can put a 74 crank with 5.5 rods and use the standard 90.5 b&ps..
where do i have to take the case lining out to clear the crank??
just the top of it???
cheers steve
yep you dont need stroker pistons with that crank, and you can keep the same rods. it may alter your deck height a bit?
as for clearancing, its a case of get the crank and turn it to see if and where it catches then give it a tickle with a die grinder
as for clearancing, its a case of get the crank and turn it to see if and where it catches then give it a tickle with a die grinder
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475 Posts
Just a query, are 5.5" Rods standard or is 5.4"? This is the length yeah?
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14,947 Posts
74mm crank is a good choice for a easy win on displacement gain (pm me if you need one ) stock rod length is 5.398 IIRC not 5.5 but either way as metric says it makes for a nice combo, suits the flat4 well and makes good power without the need to go BIG!!
SENSIBLE UPGRADE
James
) stock rod length is 5.398 IIRC not 5.5 but either way as metric says it makes for a nice combo, suits the flat4 well and makes good power without the need to go BIG!!SENSIBLE UPGRADE
James
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14,947 Posts
Stock rods are fine or if you want to upgrade the Scat I beams are a good choice, come ready balanced with uprated bolts etc too.
cheers james
cheers james
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4,687 Posts
hey, i have a 1955cc - thats a 76mm crank with 90.5 none stroker style pistons... iv used cb unitec rods which are stock length... 5.4
you guys with a 74mm crank and 90.5 pistons have a 1905cc not 1955cc.
i love my engine, it used 2 be running on 40 dells with 8.8:1 cr and it was pretty quick.. ran 16.3 down the strip with 36mm dells and tiny venturis - this stopped it revving over 5k. i changed to 40 dells and bigger vents and i could rev way higher which i needed as i had a bigger cam (web110 - engle 120ish) and scat D port heads with 40x37.5 valves... this woke the engine up a load, i reckon id hav been mid to low 15s easy.... it made just over 100bhp with 40 dells and small vents and again, stopped makin power much over 5k... thats when i put the bigger vents in, but i didnt get it dynod again.
iv now added efi and turbo, and will get it dynod soon...
my 1955cc is a load nicer to drive than my 1776cc was
do it
mabbo
you guys with a 74mm crank and 90.5 pistons have a 1905cc not 1955cc.
i love my engine, it used 2 be running on 40 dells with 8.8:1 cr and it was pretty quick.. ran 16.3 down the strip with 36mm dells and tiny venturis - this stopped it revving over 5k. i changed to 40 dells and bigger vents and i could rev way higher which i needed as i had a bigger cam (web110 - engle 120ish) and scat D port heads with 40x37.5 valves... this woke the engine up a load, i reckon id hav been mid to low 15s easy.... it made just over 100bhp with 40 dells and small vents and again, stopped makin power much over 5k... thats when i put the bigger vents in, but i didnt get it dynod again.
iv now added efi and turbo, and will get it dynod soon...
my 1955cc is a load nicer to drive than my 1776cc was
do it
mabbo
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20,431 Posts
My 1955 gave 110bhp at the crank on first couple of runs It gives 78bhp at the wheels on the RaceShack dyno after a 1000 miles
Very modest mods - 110 cam, 8.5 CR, matched inlets, fully balanced, 40 x 35.5.
But a torque curve that climbs almost vertically up to about 700 ish rpm and then is flat through out. Power curve is not at all peaky.
Exactly what I was aiming for.
Very modest mods - 110 cam, 8.5 CR, matched inlets, fully balanced, 40 x 35.5.
But a torque curve that climbs almost vertically up to about 700 ish rpm and then is flat through out. Power curve is not at all peaky.
Exactly what I was aiming for.
Confused: You mean you have a 1905 or a 1955 :incheek: :crazy: :tick: ??!Mabbo said:hey, i have a 1955cc ....
you guys with a 74mm crank and 90.5 pistons have a 1905cc not 1955cc....
my 1955cc is a load nicer to drive than my 1776cc was
Guessin with your turbo you'll be way over 150bhp judging by what metric thumbs reports?
Matt :hangloose
PS - just re-read the fact that you have a 76mm crank...apologies...long day at work
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4,687 Posts
iv got 1955cc
its turboed now but i broke the box... gay!!
still tuning it and learning megasquirt - its clever all this efi stuff
i'm hoping for closer towards 200bhp when its set up properly, but id be more than happy with 150+...
this is my bug - wouldnt expect 150+bhp would ya... hahah
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mabbo
its turboed now but i broke the box... gay!!
still tuning it and learning megasquirt - its clever all this efi stuff
i'm hoping for closer towards 200bhp when its set up properly, but id be more than happy with 150+...
this is my bug - wouldnt expect 150+bhp would ya... hahah
mabbo
Would putting a 74mm crank in a tuned 1600 be a waste of time?
would you suggest getting the parts to make a 1776 on a stock crank and then fit a 74mm instead as it sound like you all have/had 1776 motors before fitting the new crank to make 1905cc?
cheeers
would you suggest getting the parts to make a 1776 on a stock crank and then fit a 74mm instead as it sound like you all have/had 1776 motors before fitting the new crank to make 1905cc?
cheeers
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