VS unmodified 1776cc redline?

There are different factors that would determine the redline on your particular engine.

Did I say that right guys? I don't want to offend anyone or make it seem like I know what I'm talking about.

Just before it goes BOOM!

Steve:

5,500 rpm

gn

Good question I have NO idea what the Max RPM is on my 2005cc CB engine either?

Depends on the cam/rocker combo, heads, carburetion and exhaust. Gordon's advice is right on if it has an Engle W110 or something similar. If it has a stock cam then maximum rev's will be 45- 4700rpm.

Steve- if you don't know the cam, do you know what it's rated at for horsepower?

Manxman (my apologies, I've forgotten your first name. I wish more people would include it in their screen names)- Being a CB built engine (and knowing what they quite often build), 5500 or 6,000rpm is probably the redline. Same question as Steve- do you know what's in it for parts? If you don't have the build sheet, at what rpm does it seem to start to run out of steam in 3rd gear? It may rev 500, or even 1,000rpm higher, but if you pay attention you'll feel the power just start to die off. And you need to do this in 3rd gear, because in 1st or 2nd it will rev to fast to be able to tell. Al

But some people on here don't have balanced engine components.

With aftermarket cam, rockers, carb(s) and lightened flywheel you'll increase the revability, but a stock crank and rods won't run for long north of the 5,500 Gordon mentioned.  

When builing bigger,  it always comes down to the weakest link and there are many.

A balanced engine runs smoother and achieves higher RPMS without going boom.  A counter-weighted crank also helps. I've also heard of rotational balancing vs static balancing. After sitting for 25 years - I'm probably going to dismantle my 1641 cc engine.  I have 8 dowel CW crank, Engle 110 cam, 12.5# 8 dowel flywheel, and dual dellortos --- so hoping it will be a reve'er. I'll put in new rings and replaces valve spring with heavy duty springs as I'm sure mine have taken a set from sitting. Might as well swap out exhaust too. Hoping I can get some expert guidance from local Mark Tucker!

What's the estimated time that an engine can sit idle, untouched, before concern about valve springs developing a "set from sitting"?

Thanks

I think key to sitting long - is turning it over frequently and backing valve adjuster screws off.  I'm sure just sitting with doing nadda it's only a year or 2.

Some people on here aren't even balanced themselves!! Just saying.

Al, it's Roger and I think 5500~ 6000 sounds right!

Sorry Roger! I should have known. And if you pay attention, you'll feel when it's reached peak power. As I said before, it will rev higher, but you'll notice it's now laboring just a little, and it may even sound a little different.

you will find if you push it at around 4600 rpm it will start to fall off, if pushing it just short shift it at around 4500 and use the low end torque of the next gear. bill

He asked what the red line should be, not the shift points - big difference.

Red line:  (still) 5,500 rpm.

Shift points for a "stock" (no mods other than barrels and pistons) 1,776:  3,500 is nice - 4,000 tops

Valve Spring "Set"

People routinely start up old cars that have been sitting for 10-20 years (or more).  You see this on TV all the time, like on "Chasing Classic Cars".  Replace the valve springs after the engine has been sitting for only 2 years?  I don't think so.  Mine sat for 4 years while I was building the car and has been fine since I got on the road.

I would be more worried about the rings rusting to the insides of the cylinders. 

All of what has been said about 'redline' on almost any engine depending upon the engine internals and balance is correct.

If you push a common 5k-5.5K rpm rev limit on most any engine long enough and hard enough "things go Boom".

My Cobra engine was purpose built starting with a new aluminum 302cu in. balanced shaved block, it was bored to 347cu in. with a balanced/counter balanced forged crank assembly, balanced PINK rods and dome pistons, roller rockers on Ford Racing aluminum mated heads. This engine was built for me by Gessford Machine out of Nebraska, known for their top of the line Ford racing engines.

The engine was thoroughly broken in on an engine dyno, then the oil was drained, refilled, valves re-adjusted, Etc., and it was again run on the dyno for peak performance, redline was rated at 8,000rpm. This before it was shipped to me sans oil. Gessfords motto is if somethings wrong with the engine build he wants it to happen in his shop not in the customers vehicle.

I have an adjustable rev limiter on the MSD box that is usually set at 6,500 rpm for street driving but when I raced I'd often turn it to 7,400 rpm. I have never hit the 8k rpm redline. The rev limiter cuts out the ignition when rpm is reached causing the engine to stumble and the engine is still running strong 15 yrs later.

If you are smart on your tach put a small painted yellow line at around 4,500 rpm then you'll know when you are approaching rev limit with a quick glance at the tach,and if you do not have a redline mark on your tach paint a small red line or mark at 5,000rpm...other wise 'things go boom'. Once you are accustomed to hearing the engine at different rpm levels you can generally tell when the engine is starting to 'scream'...time to shut down as you are approaching rev limit.

Running your engine hard to redline with every shift is not conducive to engine life and rebuilding/replacing an engine and or drivetrain components is expensive $$$$$$...unless you are sponsored by a Nascar or Series team that rebuild engines/drivetrains constantly after each outing.

The attached super car sounds - makes me want to blow any possible kid's inheritance on a McLaren!  Nothing like the 12k whine of a F1 engine and the smell of Castrol!

https://www.youtube.com/watch?v=F7IvbIM0fZA

I like the racer trick of canting the tach so the redline (or shift point) is at 12 O'clock. Saves paint.

Wandering the paddock at vintage races I noticed a lot of tachs turned so the 12 o'clock position was in the 3-4000 rpm range. "What gives," I asked one MG racer after helping push his car up on his trailer.

He told me he marks the LOWEST part of the torque curve--downshifts when the needle gets close--because the tach is way too bouncy up high.

I suppose it's true. Just as likely, though, is he's also got a rev limiter installed to cut spark above 6500 or whatever...

Gordon, thanks for actually answering my question. 

Valve spring set and the possibility of ring rust on an engine that sits for a long time, either in or out of the car sitting on an engine stand can easily be solved by occasionally turning the engine over by hand using the crank bolt...if stored with oil while on the stand...simple really no matter the compression ratio, just pull the plugs and turn over about a dozen times, when done reinstall the plugs...

An engine builder told me this years ago...just turn it over by hand at least once a month.

It took me five years to build/finish the '48 Anglia project and the brand new engine that came with the project was pulled from the car and set on an engine stand for almost 4yrs before bring reinstalled. We turned the engine over a few times on the stand, drained the oil, refilled and changed the filter then installed the engine getting it hooked up...when we turned it over it coughed and sputtered a few times then took off idling, while warming up we were getting a just a wee bit of blue smoke along with a little black and some white coming out of the open headers(damn that was loud in a small shop!). Once it came up to temp all the smoking from the engine went away. 

So, how are we defining "redline"?

If it's the ability of the engine to not fly apart right now, then I'll buy that the redline of a non-balanced 1776 with a non-counterweighted crank, stock rods and cast pistons would be about 5500 RPM.

If it's the ability to hold together for a long time, bouncing off that redline every shift... I'd bet it's a bit lower.

That's my opinion. Your mileage may vary.

Isn't the object of the game to have an idea of the redline, but to stay away from it for long term benefit... I have been in a car that put the piston through the block not a nice experience   Ray

That is the idea, if you cant the tach with redline at the top or a little to the right with a bright yellow line about 500rpm below known or assumed redline, known as the 'caution' line and don't go over it you are good to go.

I've blown an engine before by over revving...just out of HS I got into a street race one Sat night with a new Dodge Dart 440 GTS with my '57 Chevy, Corvette engine 327, dual 4bbls and 4spd. Came off the line way above redline of 5,500 and kept my foot in it pulling away from the Dodge, power shifted to 2nd, foot still in it and 'Kaboom' horrendous noise in the engine bay. I put a rod right through the block...there was nearly a block long oil spill up to the car...definitely not a good sound or good night for me. The guy in the Dodge got the last laugh...

I consider the redline of an engine the rpm at which the horsepower "peaks" on the dyno graph, and is a function of the parts choices- camshaft duration and lift, carburetor(s), valve and porting sizes, and exhaust type and tubing size. Everything should be chosen with the intended powerband in mind. Revving higher does not make any more power! This is the rpm you shift at "occasionally" and is different than the shift points you would normally use. Most engines will rev past their redline (500-1,000rpm), but generally all that does is wear out (or even break) parts prematurely.

As Stan alluded to, it is possible to build an engine with a higher redline than the rest of the parts (crankshaft, pistons, valve springs, possibly rods, and even pushrods) will support, is poor planning and reduced engine life will result. People in the industry will tell you that is one way to build what is referred to as a "poor combo". This is why, Steve, I asked for more details in my first post; no one can give a halfway accurate assessment of what you have without more info.

VW's recommended shift point markings for each gear (at 3500rpm) on factory speedometers of all their type 1 engine'd cars ensured that the "recovery rpm" in the next gear was high enough to be capable of powering the car in almost all conditions without overheating the engine. As Gordon already mentioned, 3500-4,000rpm is a good rule of thumb. How much you play with the power you have above that is up to you. Al

Ray- Yeah, that's messy! 

ALB, thanks for the reply.  Like I stated in  my original post, My VS has a 1776 unmodified type 1.  This is the normal engine as was sold by Kirk at VS. I assume it is a type 1 with stock internals and the normal big bore kit  (90.5) and dual Kadrons.   All I was tying to get was info on the recommended redline from any owner who has access to that info.  That never meant that the car was driven to redline or shifted at redline.  My car pulls nicely to about 4200 rpm when pushed.  I shift normally at 30-3700 rpm depending on the driving conditions.  Seems like the original threat took a detour to other places.  I'm fully aware that modified engines will produce radically different dynamics. Your info was very helpful, thanks.

My understanding exactly. Want to know the redline? Put her on a dyno. Peak HP="redline" for every practical purpose unless the engine was build by drunk monkeys. 

Some dyno guys used to rev out until the valves floated, just so you'd know that number too. I don't see that so much anymore. 

The best shift point is where the engine drops right on or just under peak torque. So if your 1776 dyno's out with 98 hp at 5200 rpm and 116 ft-lbs at 3000 rpm, then redline is 5200 and the shift point in any gear is whatever lands you on or just below 3000, assuming hustling along smartly is your goal.

In this example that'd be about 5100 in 1st, 5000 in second and 4200 in 3rd.

For mileage you gotta short shift...but not too much.

No worries, Steve. As usual, we "wandered" a little during the discussion! It happens here a lot. But then, some of the best info comes out when we're "off topic"...

The reason I was a little vague in the beginning is that "unmodified" can mean a couple of different things- stock (from VW, which it's not totally, as it has dual carbs and a different exhaust) or not touched since you've got hold of it. That's why I asked what you knew about the camshaft, as it (more than anything) will give an idea of what kind of power the engine has.

Thread drift. Had a roomate years ago with a '69 lime green 911.  He had problems always fouling the plugs.  Porsche mechanic said he was lugging the engine by shifting at 2-2500 rpm and that he occasionally need to rev it up to red line and shift above 3k.  Engine sounded much better at higher revs anyhow.  

My early mentor, Al Alden, who built killer Porsche racing engines and eventually ended up with a Porsche dealership, once told me that he had gone over to Germany for an 8-week training program at the Porsche factory, back in the late 1950's.  He recounted how the technicians driving 356's around the factory area (after finishing build) seldom seemed to let the revs drop below 3,500 and usually closer to 4 grand.  Not just bringing it up to that RPM for shifts, but cruising around the factory campus and holding 3,500+ for a while.  That, with the full support of production management AND the engine designers.

These engines WILL soot up and run lousy if you only run them below 2,500 and especially below 2 grand.  That's why I always recommend cruising around town in third at 2,500-3K and then shift at 3K+  Do so, and you'll have a happier engine.  

Again (and I feel like a heel for it), I'm going to swim upstream a bit on the "redline" thing.

For me at least, the engine's "redline" has nothing to do with the power peak. Ideally, IMHO, there will be at least 1000 RPM of headroom after the power peak before "redline". On the other end of the spectrum, I don't think of "redline" as being the point of assured destruction- the idea that if you ever miss a shift and zing up 100 RPM past "redline" that you'll need to tear the bottom end apart.

I've got dual valve-springs, H connecting rods, ARP bolts, forged pistons, counterweighted forged crank, and the entire bottom end has been balanced. I should be good somewhere past 7000 RPM. The power peak of my combination is about 5500 RPM. There will be occasional times I shift at 6500 or so. However, if I spin past 7000 on a missed shift or something-- I'll mutter at myself, but I won't tear the engine apart. The combination of parts is good for that, and I'm comfortable trusting it on rare occasion, but I wouldn't want to shift there every time I took the car out.

I've got my "redline" marked at 6500 RPM. It's the last point where I can be reasonably assured the engine will hold together if operated occasionally, but not regularly.

Shortly after I bought my IM I replaced the stock 1600 with a 1776.  It had a counter-weighted crank, stock heads (with single springs), 40mm Webers, and a very mild cam.

The engine would rev to 5500 rpm, but power-wise she was done by 5000 rpm.

At around 5500 the valves began to float and the engine stopped producing anything except noise.

Stan pretty much says what I was taught:

The "Redline" on any engine, properly constructed, is the maximum, safe, operating engine speed.  With the engine that I built, I suppose that I could set a "redline" at 6,000 rpm or so, but the reproduction "VDO" Tach I have starts the "Red Zone" at about 5,500 or so and I figured that was as good a Redline as any.  

Would I shift at 4K rpm?  Sure.

Would I drive at 4,000 or a little over?  Sure....And I have for a few hours at a stretch from time to time.  Now that I have a 3:88 rear end, I can do the same road speed at around 3,400 engine rpm and that's better and I'm happier.  These are tough little engines and they can take a lot of sustained RPM's but they don't equate rapid, often acceleration (think Drag Racing) to engine longevity unless they've been modified a lot.  Stock engines just like to run.....and run....and run.

BTW:  My tach's "Red Zone" is a two-step affair, with a thinner red line starting at 5,500 rpm, and a much thicker red line starting at 6,000 rpm.  Just FYI.

Come to think of it I also did put a connecting rod through the block on a 1974 VW beetle 1600cc engine at 70mph .. I had to have it towed 200 miles home, with all my stuff in it after finishing my spring term at uni.  No fun, at all when your a cash strapped student.... that was the last aircooled VW I had for a while after. 

My engine is balance and blueprinted. I've been told I'm good to 7500. Never going there though, I don't want to pound the case out like that.

Power peak is 6000, torque peak is around 3000(can't remember exact rpm). My limiter is set for 6250, used to be 6500. Nothing to gain up there.

I usually shift at 3500 to 4000 unless I'm really on it, then it goes up to 6K or so.

I'd keep it under 5K on a stocker, nothing to be gained beyond that.