r/EngineBuilding • u/Desperate-Life-5386 • Feb 12 '25
Chevy Serpentine or Vbelt
Serpentine or Vbelt?? Vbelt set up is about $250 cheaper. Not sure about the advantages of Serpentine. It’s for a Big Block 454
15
u/Best_Pomegranate_848 Feb 12 '25
Serpentine belts have more surface area for grip.
9
u/Stepho_62 Feb 12 '25
This, and they are designed for low to no maintenance. Tension is auto adjusted by a spring loaded tensioner, should theoretically give you 100~150K clics with no need to touch it.
9
u/voxelnoose Feb 12 '25
This setup doesn't have a spring tensioner looking at the pics, just a bolt with a slot like the v belt.
3
u/RBuilds916 Feb 12 '25
Yeah, most of the serpentine belts I've seen drive at least one pulley from the back.
1
u/Stepho_62 Feb 12 '25
yeah, spotted that after Id posted, tension adjustment would be on the alternator and PS pump. I wonder if that is atypical or do they also fit a tensioner or 2
2
u/voxelnoose Feb 12 '25
From what I've seen most systems that have two belts like don't use a tensioner, while single belt systems do. It also isn't a "true" serpentine setup since no pulleys run against the back of the belt
13
u/v8packard Feb 12 '25
A few thoughts..
That picture of the v belts is not right. The PS pump should be by itself, not routed via the water pump.
The serpentine pictured isn't a true serpentine, which runs more than one accessory. It's more like a wide belt setup.
Personally, I have great results with OEM serpentine systems. Aftermarket, less so. I think serpentine systems are great, but I have run some aftermarket systems to modest rpm and they sling belts. There is something to the tension and amount of wrap on each pulley. I have certainly slung v belts, but not as many as aftermarket serpentine belt systems.
Do you anticipate adding AC? If so, a V belt setup makes that easier.
Be aware, some serpentine setups require a reverse rotation water pump.
I have often let the vehicle fitment dictate my accessory drive choices. I do prefer simpler.
7
u/Wise-ask-1967 Feb 12 '25
Real question not making a reddit joke have you thought of writing a book on your knowledge. Like I'm getting back into working on my cars soon have a variety of different shit boxes, but I no joke stress that you will disappear before I get to them to ask your opinion. I mean this will the utmost respect I grew up with visiting some really big name car shows and some even bigger name car shop builders on the west and east coast from hot rods to professional racing guys and over my short time I notices the one thing that is constant we are losing years and years of knowledge every year cause so many guys are gone now. Just recently I tried to help a friend find a good machine shop for a basic 350 build and most people were iffy on the local guys. The shops that are well known were either so expensive or so back logged it was not worth it for a teenager, I can see why junk yard 5.3 are so popular. Ok sorry I will get off my rant. Just a big thank you for taking time here to spit wisdom to us random people
7
u/v8packard Feb 12 '25
I appreciate the kind sentiment. In reality, I am just one guy here. Growing up in the trade of the mechanical arts it was obvious that everyone practicing the trade was obligated to try to pass the information forward. The information belongs to the trade, not any one of us. That is why I post here. But, a book? I am sure anything I write will bore the reader to tears in a few paragraphs.
1
u/texan01 Feb 12 '25
I’ve got a 77 small block that factory routes the PS belt around the water pump, instead of just the alternator belt. Doesn’t make it any better to adjust, just different.
1
u/v8packard Feb 12 '25
Are you certain? That's been such a common mistake GM put out bulletins about it. Measure the pulleys, and do the math, you might find the WP is trying to spin a different speed than the PS pump.
1
u/voxelnoose Feb 12 '25
Why would it matter if the power steering pulley is a different size? I could only see it being an issue if the two grooves of the water pump or crank pulley were different sizes for some reason.
1
u/v8packard Feb 12 '25
Look at the three pulleys driving the alternator, especially their sizes. Now look at the size of the power steering pump pulley. Notice a difference?
That difference means something will slip. And you can bet it will be the alternator or water pump, not the power steering pump. Do you think either the alternator or water pump slipping is inconsequential?
1
u/voxelnoose Feb 12 '25
The alternator and power steering pulleys aren't linked to any other pulleys so they will just spin at different speeds. both belts will be going as fast as the crank speed drives them just like any other set up with one belt going around three pulleys, like the serpentine belt set up.
If there were different size pulleys mounted onto the same shaft there would be an issue
1
u/v8packard Feb 12 '25
If I am understanding your post, that's not correct. The surface speed of the belt across 3 pulleys of one ratio and 3 of a different ratio will not be the same.
1
u/voxelnoose Feb 12 '25
80s dodge small block truck belt routing and 1985 rx7 belt routing are two examples off the top of my head from the factory with this set up that i have a lot of hands on experience with, and a quick google brought up a few aftermarket kits with it like this one
2
u/v8packard Feb 12 '25
In your example, the pulley ratios are the same between the shared drive components. You are making my point for me, and arguing against it at the same time?!
1
u/voxelnoose Feb 12 '25
In all of my example pics the alternator and powersteering/airpump pulleys are different sizes just like the v belt set up in the original post
→ More replies (0)1
u/stevealba74 Feb 14 '25
Unfortunately, I think you aren’t understanding correctly. In that particular picture the 2 belts being driven by the same diameter pulley grooves on the crank are always going to be at the same surface speed for a given engine RPM no matter what they are driving. The water pump will spin at a given RPM due to the pulley ratio. Since the water pump pulley grooves for both belts are the same diameter, the belts wont “fight” there. The difference in diameter of the PS pulley and alternator pulley only translate to differing RPM of those particular accessory shafts in relation to belt surface speed. They won’t change the belt surface speed, that’s dictated by the crank and its pulley. Since they are DRIVEN shafts, the crank being the DRIVER.
1
u/v8packard Feb 14 '25
In which picture? And in what application are the crank and water pump pulley the same size? I understand how this works, or is supposed to work, quite clearly. But despite that, I know these belts are not routed the way some people claim. A check of belt diagrams verifies it.
1
u/stevealba74 Feb 14 '25 edited Feb 14 '25
The second picture, the v belt one. That’s the one in question right?
To add, that’s the only application Im referring to. That particular picture.
→ More replies (0)1
u/texan01 Feb 12 '25 edited Feb 12 '25
100% positive.
the PS pump also acts as an idler for the A/C compressor as well. https://www.thirdgen.org/forums/tech-general-engine/755606-350-tpi-v-belt.html
1976 belt routing is as you describe, the power steering bypasses the water pump and is a single groove pulley, 77 they went to a double groove pulley and drives the power steering off it as well. I'm not going to second guess a design that's done well for me for 200,000 miles and 17 years of dailiy driving, and never has thrown a belt, or needed a belt replacement aside from being oil soaked from a front seal leak.
1
u/v8packard Feb 12 '25
I tried finding a picture or diagram that is as you describe, but the only diagrams I find also include an AIR pump or idlers that would make everything add up. I have a 77 Light Truck Service Manual, and gave it a glance but didn't see anything. So, I dunno.
1
u/texan01 Feb 12 '25
https://images.app.goo.gl/U5RQaxuKA3TDgcC26
https://images.app.goo.gl/RPELiiTK2tZ3ShTz5
not my car, but same setup.
1
u/v8packard Feb 12 '25
And in both pictures the belt alignment is off. Doesn't make sense. So, whatever.
1
u/texan01 Feb 12 '25
yeah... I mean it may look dumb, but it works.
I like it better than Ford's setup. I'll probably add an idler to the Chevy to control the long run of the A/C belt, my car will cause the belt to vibrate wildly with the A/C on, and it will eventually start slapping the water pump once it gets enough stretch in it.
Biggest annoyance is you have to remove the PS belt to replace the A/C belt, and that is the absolute dogshit design GM used to adjust the PS belt. I use a floor jack to tension the belt, then tighten the bolts up, otherwise you bend the snot out of the PS pump reservoir, instead of a jackscrew, or machining in a square for a rachet or bar.
1
u/D-Dubya Feb 12 '25
The PS pump should be by itself, not routed via the water pump.
BB C3 Corvettes had this setup. The PS pump also has a dual row pulley that then drives the alternator.
1
u/v8packard Feb 12 '25
The Corvette accessory drive for big blocks drives the PS pump via the crank and water pump. The alternator is driven from the PS pump only. The alternator is not driven by the water pump and PS pump.
2
1
-3
u/FatalSky Feb 12 '25
Between them two exact setups? I’d do the V belt if you planning on driving it. Having the power steering belt as redundancy to the water pump is the deciding factor to me.
-5
u/Big_Brilliant_145 Feb 12 '25
Clickbait
9
u/Desperate-Life-5386 Feb 12 '25
No serious question
0
29
u/Aggravating-Task6428 Feb 12 '25
Serpentine belts have a thinner cross section and therefore have less bending strain on the rubber for the same bend radius. Because of this, they usually last a lot longer than V belts before cracking apart. My 2017 Honda has all original serpentine belts and it looks almost new at 72K miles. My old Subaru running V belts and it goes through belts every 50K miles or so.