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MConstable
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Joined: May 04, 2004
Posts: 1822
Location: Saint Charles IL
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 Posted: Wed Dec 13, 2017 1:30 pm Post subject: 5.4 versus 5.5 rods |
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Just curious in opinions, I got talked into 5.5 rods for my 2110 engine for my Thing, I was set on 5.4's, heads are Tims stage ones.
Other than, obviously I'll check the deck height whenever time comes to build it, But is there a benefit to the little extra bit of rod length? |
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Dan Ruddock
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Joined: October 25, 2012
Posts: 3594
Location: Sarasota, in my adopted state of Florida
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| Posted: Wed Dec 13, 2017 1:40 pm Post subject: Re: 5.4 versus 5.5 rods |
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| Long rods are race engines and short rods are for street engines. Dan |
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Pruneman99
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Joined: February 22, 2012
Posts: 5013
Location: Oceanside
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| Posted: Wed Dec 13, 2017 2:01 pm Post subject: Re: 5.4 versus 5.5 rods |
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| No way you will tell a difference. More important is deck height and engine width but IDK if that matters for a Thing or not. |
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[email protected]
Samba Member
Joined: August 15, 2002
Posts: 4394
Location: Brew City
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| Posted: Wed Dec 13, 2017 2:07 pm Post subject: Re: 5.4 versus 5.5 rods |
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| MConstable wrote: |
Just curious in opinions, I got talked into 5.5 rods for my 2110 engine for my Thing, I was set on 5.4's, heads are Tims stage ones.
Other than, obviously I'll check the deck height whenever time comes to build it, But is there a benefit to the little extra bit of rod length? |
Why? I just finished a 2110 that I am about to fire up in 10min and with the 5.4" rods, I had negative .015" deck height to start with. I used .060" barrel shims and trimmed my chambers down to 53cc for 9.5 to 1 CR.
I only use the 5.5" rods on 1914's and 2165's so setting deck height isn't such a PITA.
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UK Luke 72
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Joined: September 07, 2011
Posts: 2867
Location: Little Britain
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[email protected]
Samba Member
Joined: August 15, 2002
Posts: 4394
Location: Brew City
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| Posted: Wed Dec 13, 2017 2:24 pm Post subject: Re: 5.4 versus 5.5 rods |
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| UK Luke 72 wrote: |
Seems like one of those where the only thing you need to consider is putting the piston in the right place at TDC... Whether it takes a 5.325/.4/.5/.6 for our purposes is seemingly irrelevant.
Although if you do need a 5.325 or 5.6 I would maybe question if you have the right combination of pin height/crank stroke and cylinder length. |
Exactly.
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jpaull
Samba Member
Joined: February 22, 2005
Posts: 3460
Location: Paradise, Ca
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| Posted: Wed Dec 13, 2017 2:56 pm Post subject: Re: 5.4 versus 5.5 rods |
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| Dan Ruddock wrote: |
| Long rods are race engines and short rods are for street engines. Dan |
Shorter then what? Longer then what? You have no reference point.
Rod ratio has a reference point. Cause its short or long as compared to the crank stroke.
In relation to the crank stroke, the stock 1600 uses a "longer rod" then any 5.4 or 5.6 rod in any 82-84 stroke engine.
So you can say VW chose to use a long rod in their little non race engine.
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[email protected] MPH 1/4 Mile & 8.1 @ 83.7MPH in 1/8 Mile with Mild Type 1 VW Mag Case 2234cc commuter engine in stock weight bug w/only .491 total lift(CB2292 Cam), 42x37 heads, 48idf's, Street tires, Belt on, Mufflers, Pump gas, video of the run here: https://youtu.be/M3SPqMOKAOg
Transmission by MCMScott:
Rhino case, Klinkenberg 4.12, Superdiff, 002 mainshaft with 091 first idler. Weddle 1.48 Third & 1.14 Fourth. |
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Bad bug
Samba Member
Joined: March 11, 2006
Posts: 1127
Location: Jamaica
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| Posted: Wed Dec 13, 2017 3:51 pm Post subject: Re: 5.4 versus 5.5 rods |
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| jpaull wrote: |
| Dan Ruddock wrote: |
| Long rods are race engines and short rods are for street engines. Dan |
Shorter then what? Longer then what? You have no reference point.
Rod ratio has a reference point. Cause its short or long as compared to the crank stroke.
In relation to the crank stroke, the stock 1600 uses a "longer rod" then any 5.4 or 5.6 rod in any 82-84 stroke engine.
So you can say VW chose to use a long rod in their little non race engine. |
I agree with what you are saying here. |
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Dan Ruddock
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Joined: October 25, 2012
Posts: 3594
Location: Sarasota, in my adopted state of Florida
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| Posted: Wed Dec 13, 2017 4:11 pm Post subject: Re: 5.4 versus 5.5 rods |
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| jpaull wrote: |
| Dan Ruddock wrote: |
| Long rods are race engines and short rods are for street engines. Dan |
Shorter then what? Longer then what? You have no reference point.
Rod ratio has a reference point. Cause its short or long as compared to the crank stroke.
In relation to the crank stroke, the stock 1600 uses a "longer rod" then any 5.4 or 5.6 rod in any 82-84 stroke engine.
So you can say VW chose to use a long rod in their little non race engine. |
OK I will get more specific. For a 6500 rpm street engine there is no need for anything higher than 1.62 to one. The pistons and cylinders will still last longer then the valvetrain and cylinder heads and and the power band will be better suited for a street engine. VW used longer rods than it needed. The Honda D16 had a 1.52 to Ratio and the Honda engine has proven to last far longer than any VW Air cooled engine.
On a race engine which revs are much higher than the street engine having the longer rod will add more top end power and reduce friction at those rpm’s. I say focus on the problems the VW engine has and not the ones that it does not have. Plus the short rod fits the VW engine better and fits the car better in street use.
Dan |
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esde
Samba Member
Joined: October 20, 2007
Posts: 5966
Location: central rust belt
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| Posted: Wed Dec 13, 2017 4:18 pm Post subject: Re: 5.4 versus 5.5 rods |
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what's most important to you?
getting the rod ratio you think you want?
Having the engine go together easily?
Having it fit the car (and exhaust, tin, etc) ?
You could argue different combinations of parts, depending on what you are doing..
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[email protected]
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Joined: August 15, 2002
Posts: 4394
Location: Brew City
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| Posted: Wed Dec 13, 2017 4:37 pm Post subject: Re: 5.4 versus 5.5 rods |
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| Dan Ruddock wrote: |
| jpaull wrote: |
| Dan Ruddock wrote: |
| Long rods are race engines and short rods are for street engines. Dan |
Shorter then what? Longer then what? You have no reference point.
Rod ratio has a reference point. Cause its short or long as compared to the crank stroke.
In relation to the crank stroke, the stock 1600 uses a "longer rod" then any 5.4 or 5.6 rod in any 82-84 stroke engine.
So you can say VW chose to use a long rod in their little non race engine. |
OK I will get more specific. For a 6500 rpm street engine there is no need for anything higher than 1.62 to one. The pistons and cylinders will still last longer then the valvetrain and cylinder heads and and the power band will be better suited for a street engine. VW used longer rods than it needed. The Honda D16 had a 1.52 to Ratio and the Honda engine has proven to last far longer than any VW Air cooled engine.
On a race engine which revs are much higher than the street engine having the longer rod will add more top end power and reduce friction at those rpm’s. I say focus on the problems the VW engine has and not the ones that it does not have. Plus the short rod fits the VW engine better and fits the car better in street use.
Dan |
Come on......you can't compare the longevity of a completely different design watercooled engine to an aircooled engine and come to the conclusion that the rod ratio is the determining factor. There are WAY too many variables.
The short rod does not fit the 1914 or the 2165 "better" at all. All other things being equal, if you just slap it together, the deck height is over .130" To correct it, you would have to cut the barrels or to just get it done, you have to flycut the head to the low 40's. This is going to change the width. You can almost keep a stock width by using the 5.5's.
As we started talking about on another post, getting the "right" rod ratio doesn't really mean much for a street engine. A race engine is a totally different debate.
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Dan Ruddock
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Joined: October 25, 2012
Posts: 3594
Location: Sarasota, in my adopted state of Florida
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| Posted: Wed Dec 13, 2017 4:54 pm Post subject: Re: 5.4 versus 5.5 rods |
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I understand all that Roy and I agree on a street engine the ratio does not matter that much. You pick the rod that fits the best for what you are building. We agree more than you think. Just trying to dispel the gotta have long rod myth. I was a believer in my past.
Dan |
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esde
Samba Member
Joined: October 20, 2007
Posts: 5966
Location: central rust belt
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| Posted: Wed Dec 13, 2017 5:16 pm Post subject: Re: 5.4 versus 5.5 rods |
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| Dan Ruddock wrote: |
| gotta have long rod myth. |
ha!
I'll show myself out..
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modok wrote:
Bent cranks are silent but gather no moss. I mean, ah, something like that. |
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Dan Ruddock
Samba Member
Joined: October 25, 2012
Posts: 3594
Location: Sarasota, in my adopted state of Florida
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| Posted: Wed Dec 13, 2017 5:19 pm Post subject: Re: 5.4 versus 5.5 rods |
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You got me.  |
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bugguy1967
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Joined: January 16, 2008
Posts: 4341
Location: Los Angeles, CA 90016
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| Posted: Wed Dec 13, 2017 6:07 pm Post subject: Re: 5.4 versus 5.5 rods |
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Stock width is overrated, IMO. Narrower engines are "lighter and tighter"!
MConstable, I'm a fan of the 5.325" rod and 82 stroke combination. You'll have to likely trim your barrels a bit, but your pushrods will be lighter and stiffer, your studs will flex less, making your entire valvetrain more stable than a longer setup. If you can swing it, buy some pistons with higher pins too.
Another positive is your carbs will be easier to work on. |
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fivelugshortaxle
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Joined: May 13, 2011
Posts: 4254
Location: Aumsville, Oregon
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| Posted: Wed Dec 13, 2017 6:08 pm Post subject: Re: 5.4 versus 5.5 rods |
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Unless you're worried about semantics, 5.4 rods are good with 82 cranks....5.5 with 78.....5.5 or longer with 84 or bigger cranks.
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2332 with lots of goodies....
Rotating assembly balanced by Brothers VW
4340 84mm crank
AA 94mm p&c' s
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Magnum straight cuts
Steve Long XR310 on a 106
CB 1.4 rockers
CB Magnaspark 2 distributor
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Dan Ruddock
Samba Member
Joined: October 25, 2012
Posts: 3594
Location: Sarasota, in my adopted state of Florida
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| Posted: Wed Dec 13, 2017 6:43 pm Post subject: Re: 5.4 versus 5.5 rods |
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| I am working on a 84 mm with Porsche 5.352” rods right now. Will have a 1.62 ratio. I will have to clearance the underside of the piston for backside of the rod to piston clearance. This set up is old school and was very popular in the 80s and 70s. I guess I’m getting old school. Some of the new school ideas are better and some are worse. Dan |
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DeathBySnuSnu
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Joined: August 25, 2012
Posts: 1183
Location: MS
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| Posted: Wed Dec 13, 2017 6:57 pm Post subject: Re: 5.4 versus 5.5 rods |
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You would have to make a large difference in rod/stroke ratio to tell a difference in a street motor. That would take a lot more than a .1 change in length.
My preference?
As long as it is over 1.6 to 1 It is golden.
I have increased rod length in other motors to get them UP to 1.6
The vw has a really long rod to begin with around 2 to 1.
KB used to stay around the 2 to 1 for their nitro motors. |
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fivelugshortaxle
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Joined: May 13, 2011
Posts: 4254
Location: Aumsville, Oregon
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| Posted: Wed Dec 13, 2017 7:16 pm Post subject: Re: 5.4 versus 5.5 rods |
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| Dan Ruddock wrote: |
| I am working on a 84 mm with Porsche 5.352” rods right now. Will have a 1.62 ratio. I will have to clearance the underside of the piston for backside of the rod to piston clearance. This set up is old school and was very popular in the 80s and 70s. I guess I’m getting old school. Some of the new school ideas are better and some are worse. Dan |
Mark Hebert built his like this. Torque
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Good things come to those who wait.
2332 with lots of goodies....
Rotating assembly balanced by Brothers VW
4340 84mm crank
AA 94mm p&c' s
Total seal 2nd ring, rest are Grants
5.5 h beams
Magnum straight cuts
Steve Long XR310 on a 106
CB 1.4 rockers
CB Magnaspark 2 distributor
NGK D7ea plugs
A1 lowdown 1 3/4 with single muffler
Dellorto 48's with 40 venturies
Kennedy Stage 2 with Daiken disc |
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mark tucker
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Joined: April 08, 2009
Posts: 23937
Location: SHALIMAR ,FLORIDA
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| Posted: Wed Dec 13, 2017 11:35 pm Post subject: Re: 5.4 versus 5.5 rods |
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| Dan Ruddock wrote: |
| Long rods are race engines and short rods are for street engines. Dan |
thats so funny....so....why did chrysler use a 6.125 rod in thier 273, 318,340,360 and more?my 340 has less stroke than one of my vw motors...and about the same as my 2332.. so...was it so we could race all those mopars to the track and at the track and back from the track? and like a 6.7 or is it 7.2?...rod in some of thier big blocks....I think my 241 cid v8 motor had 6.125...or possiably longer...could that have something to do with those motor lasting so long???and the short rod Chevy's&fords needing boring over size ...with half the mille's ??hmm now I wonder about that new nissan with the variable stroke&cr that has the piston &rid almost perfectly inline all the time when it;s running witch cuts massiave amounts of fricksion.... yes long rods work, yes longer rods are good. yes they have less cylinder wall fricksion, yes shorts rods are more prone to breaking...yes short rods are harder on cylinder walls and pistons...yes you did good getting the longer rods. no I doubt you can feal it with a butt dyno. yes it may move the torque band up or 50 rpm. yes it should also lower oil temps. no you dont need to over think it. yes I paid a lot of extra $$ for 1/2" longer rods in one of my personal v8's.yes I even bought a set about .200 longer than those.....shit I sure could of saves a lot of $$ on parts if i knew the way to go was so simple and short....lived |
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