Chassis dyno for engine break in, Is it a good idea? Options

[nine14cats]

If all goes well The Beast™ will be back in my garage by October 28th. Randal and I can then finish all of the little things and she will be ready to go.

As the motor is newly rebuilt with ZERO hours on it, I was thinking about the best way to break in the motor. Our engine builder has given us a sequence that he uses. Our first thought was to take it to the track and use the first 2 sessions to break it in. However, there is a risk that if we run into issues we will be far from home and have to deal with the inconvenience of coming home in the middle of the day.

I have a chassis dyno that is close to me and gets $135 / hour to set up your car. The unit is programmable for the load on the car. I'm thinking this may be a much easier way to break the motor in. The dyno is located in a business park, so the owner says that 20 minute pulls are no problem. Two pulls and we should be good to go. I could then bring the car home, change the oil, and be ready for some fun!

Anyone ever done this? Engine dyno's break in motors all time, so I don't see a downside.

Any comments / experiences would be appreciated.

Thanks,

Bill P.

[Dave_Darling]

Sounds good to me! Make sure to have all of your tools and such with you, to make sure nothing goes wrong. (And remember, if it does, it'll be the one thing that you left the correct tool at home to deal with!)

Keep an eye on the gauges; with less air flowing over the car and more friction in the motor you may have a heat issue.

I say do the 20-minute cam break-in at home, then head over to the dyno shop!

--DD

[Joe Ricard]

Probably a better way of doing things as you can monitor all the gauges including A/F ratio by way of the dyno.

[john rogers]

Wayne Baker's rule of thumb is "an hour on the dyno is worth four hours at the track". He is right.

[Twystd1]

OK, Here is my opinion. Based on what I know and what the professional engine builders that I know handle this situation.

There is no safer way to break in an engine if the engine is already in the car.

Especially if you have good data logging and an EGT and o2 rig.

I have spent 3 nights this week dynoing cars.

2 nights at Pro Street. (Ricers on Hondata)

And 1 night with Stewart VanDyne and John Edwards at Lance Nists dyno shop. (Redline, Electromotive)

Almost ALL of their engines are dynoed before they race em. Either on a engine dyno or in the car on rollers.

I can't think of a better way to do this. It is a controlled environment that you can also see and hear what is going on.

And once the cam is broken in. You get to set it up right.
PEDAL TO THE METAL tuning.

Fun stuff.

DO IT.

Clayton

[nine14cats]

How do you plumb in for an A/F ratio gauge? Do you need to drill in another bung in the header for the sensor?

I don't trust someone's "canned" fuel mixtures. I want hard data through the entire rev range. I need to call Mat Lowrance on Monday and see if he approves of a dyno to break in for his motors. I can't see how he would disagree, but I also know that engine builders and fabricators in general are more of the artist mentality, not engineers. So he may object. I guess I'll cross that bridge when I get there. All I know is that I want data.

Last thing we need is to have an engine meltdown at redline because the motor was lean. Seems pretty sensible if I'm paying for dyno time.

So how does an engine or chassis dyno take the A/F ratio?

Bill P.

[Twystd1]

A wide band o2 sensor (Lamda) and EGT are your friends in this circumstance.

A fuel metering/measurement system will allow to you look at your BSFCs and help target your tune.

And yes you need a bung for the o2. An extractor exhaust like a Type 1 or Type 4 is too long put a o2 at the end of the pipe and expect critically accurate data in real time. (I.E. smog machine setup)

And no you don't necessarily need a bung for an EGT. You can simply drill a hole in your exhaust and clamp it in place with a stainless hose clamp.
(4 inches or so from your exhaust port is best, if possible)

Next question is... How the hell do I fill four 3/16s holes I just drilled in my totally bitchin and expensive ceramic coated headers???????????

Just thread it for a 3/16s allen "set screw" and safety wire it in by drilling the set screw and tossing a wire through it and wrap it around your pipe.

That allows you to install an EGT sensor whenever you want to.

If ChrisNprider will post up the set of headers I sold him. You can see that exact setup. Works bitchin and is fast to plug up. Or remove screws to use on a dyno.

This assumes the dyno you are using has solid data logging and has an EGT probe you can use.

And head temp. And oil temp...etc...etc...

Does this take time and money? YUP

Is this one of the best ways to set up an engine? YUP

Realtime data logging is the only way I know of to really know what the engine is doing.

Note: Your engine will take as much as timing and fuel as IT wants.
If you listen to the engine and watch the data, interesting things happen.
YOUR ENGINE WILL TELL YOU WHAT IT WANTS.
Then it's your job to deliver the goods to your engine.

This is a most interesting symbiosis.
IMHO: Thats in part why Jake, or Stewart Van Dyne or Darrin Morgan and many others are so good at their craft.
They understand this relationship and exploit it to the fullest.

No two engines are the same. Each one wants a different tune to maximize potential. And an experienced technician can really help you on this.

In truth. Guys like Jake and others have more pertinent data specific to your question than I.

I am a pretty solid back yard mechanic at best. Not a pro. (Far from it)

I suggest you wait for Jake and others to get back from their weekend and get some more data from the guys that do this for a living.

More useless data: You and I can't hear pinging on a dyno very well. Unless it's pretty loud.
Problem is. By the time your hear it. It has been going on long before it became audible.
Thats why the instrumentation of the engine is so important.
It helps keep you in the safe zone.

And gives you an idea on how far you can enter the danger zone.

I hope I have confused you even more than my previous post..... (IMG:style_emoticons/default/chair.gif)

Cheers,
Clayton

[byndbad914]

I just chassis dynoed today for mostly grins, but I wanted to see my A/F now at altitude as I have changed jetting a lot since moving to a mile high. The chassis dyno will have an O2 sensor that they can attach to the end of your exhaust as Clayton mentioned. I sorta disagree tho' that they aren't very accurate... I have found them to be rather accurate and we have pretty short exhaust systems too. Cat converters throw them way off, but headers and a race muffler will be pretty accurate IMO.

I also agree with dyno as a break-in so you can tune it and keep an eye on the A/F and so forth. I personally prefer engine dynos and really don't like chassis dynos as if you have an issue/oil leak at a seal/etc it is much easier to handle before the engine is in. That said, if the chassis dyno seems to be your more convenient option, it should be fine. The load on all the drivetrain parts is more extreme than any front straight pull you will ever make tho' and that is what makes them rough on stuff.

I have to download the vid my friend shot and do some editing to shorten, will post on youtube and let you guys know so you can hear how long it takes my ripper of an engine to climb from 3000-6500rpm (I have a stumble I haven't figured out yet since moving to CO at 6500rpm - engine is good for 8K no problem..)

http://www.youtube.com/watch?v=A5Viav1NKhQ

[Brett W]

I would build some det cans and attach them to the heads. They will tell you when the engine is detonating.

You really need to be able to watch individual cylinder EGTS and O2 readings, but if you can't do that a least having a sensor in each collector will give a more accurate reading while tuning individual cylinder trims.

Using a dyno is indeed the best way to fly. You can concentrate on the engine and nothing else. Just make sure you are using a brake dyno instead of an inertia dyno.

[MattR]

unless you can apply load on the dyno, i wouldnt rely on it for break in.

to seat the rings, you use the cylinder pressure to push out the rings during the non combusting 3 cycles of the engine so they seat properly with the crosshatch on the cylinder. every time i've used an engine dyno to break in a motor, you use lots of load under low rpm to seat the rings. it usually takes 15 minutes on the motors i do after the engine is warm and then its time for full flogging. and in the first few minutes, we never went above 3-4k rpm (on a race motor) to prevent a crosshatch from snagging on a ring. this is with an aluminum liner, 2 ring iron ring, and low cross hatch (for low drag on 30 hour motors). I cant pass this off as advice for every motor, but i think a chassis dyno would be a waste.

[Brett W]

Dyno Dynamics, Mustang, Rototest, etc all offer brake chassis dynos. This will allow you to properly load the engine at all load points. It will be fine breaking in a car on such a dyno. A Dynojet and many Superflows are inertia Dynos. They will not allow for engine loading. They only measure acceleration.

[nine14cats]

Dyno Dynamics, Mustang, Rototest, etc all offer brake chassis dynos. This will allow you to properly load the engine at all load points. It will be fine breaking in a car on such a dyno. A Dynojet and many Superflows are inertia Dynos. They will not allow for engine loading. They only measure acceleration.

The one closest to me is a Dynapack 4000. Supposed to be programmable for load.

Bill P.

[MattR]

Cool. The only experience i have with chassis dynos is for peak power runs (to tape on your window for car shows). Good to know!

[Twystd1]

Cool. The only experience i have with chassis dynos is for peak power runs (to tape on your window for car shows).

Thats some funny shit Matt.... And spot on for many guys that just need bragging rights. I watched that exact circumstance last week getting ready for Pomona.
Funny stuff.......

Yet in the hands of a pro... A chassis dyno is a very cost effective tuning aid.


I have been spending a lot of time at chassis dyno shops as of late.
I have been learning a lot.
And in the hands of a pro... They are great tuning aids.

Yo, I hang out at another coffee house... Gimme a call.

Bring another cute chick..... The last one you brought rocked.....

Clayton

[MattR]

clayton, where's the new hangout spot? brian told me he was thinking about buying the old one, but i see a new aloha grill there... so i guess it didnt work.

[Twystd1]

Mattster...

Gimme a call..
WE hang out at the Gypsy Den in CM... Great looking poontang strolls through too..!!!!!

They even have real food...??? Who woulda thunk..?????

LaterZzzzz.

Claytonovich East of KRACKATOA