Pete79L82

With all the engines that are built here on the forum, I see only a handfull of guys that have them dynoed before they put them into the car. I am curious why so many people don't have them dynoed first?

Most quality engine shops have dynos. When we dyno a motor every thing is checked over and the motor starts up immediately. The cam is broken in properly. You are able to insect the oil filter. You are able to find the correct timing and jetting. You find out that the motor makes the power it should and that the combination works together. When you are done you know that everything works, there are no noises or vibrations or oil leaks.


There are quality performance engine shops throughout the country so finding one close to you shouldn't be a problem.

I would think taking advantage of services like this would save a lot af agrivation later on.

ORVette

I have a crate motor, I just had to trust GM. I do have a couple questions though. I am going up to Beaverton tommorrow to see if I can get a chance on the free portable chassis dyno day, and I don't know what to expect. I don't think they are going to be giving tuning time, just free pulls, so I've got everything set up the best I can going in as far as timing and carb adjustments. I want to know if there will be any expectations I need to meet as far as equipment or anything. I have a TH400-does the machine make the pull in 3rd gear? If anyone could explain what takes place at a dyno session, I'd sure appreciate it. Thanks!

467-Ratman

Pete79, I completely aggree with you on that one! When I built my engine we made a test stand for it and ran it for about 45 minutes each time, to check for leaks or anything strange. I asked about taking it to be put on a dyno and the guys said that its really hard on the engine and not to do it. I think that was bad advice. I am now going to a shop here in Michigan that has a chasis dyno, we are going to see just how many ponies are under the hood!

redvetracr

Pete,
It`s a very long (and sad) story but I dynoed my motor, I drove 180 miles to a guy who dynoes motors and does head work NOT an engine builder, I wanted a NON biased opinion. A total waste of time and $550 (which includes race gas and diesel for my dually). I have changed EVERYTHING (except for the epoxy dam in the intake he built to fix a cool running cylinder) back to the way it was before the dyno day and finished third (out of about 50 cars) at the July vintage race at Road America/Elkhart lk. WI. Water temp at 160 (I don`t think so) and stagger jetting my square jetted TOE carb (changed that also) and the Moroso "pull toy" used to find a weak spring well it said mine were 210 but the next day the Rimac (sp??) tester read 250 lbs. he said the moroso tool is "dead on". He also uses a 20 year old method of setting valves, every 90 degrees (starting at TDC) you set #1 (both I&E) then turn 90 and set #8 and so on through the firing order. I use the intake goes down and starts back up to set the exhaust and exhaust just opens to set the intake method. Obviously I won`t be taking that trip EVER again. ...redvetracr

MotorHead

They wanted $750 to dyno mine, if it was included in the price of the rebuild or a couple of a hundred bucks I would do it but I think the price is the major reason why many don't do it and the fact an engine dynometer is very expensive piece of equipment and not engine reuilders have them although I agree they should :D

Fevre

Pete

What are your thoughts on chassis dynos? It seems to me those would be better than just dyno it on a stand because then you have all the other factors included like exhuast, trans and fuel delivery plus what ever else might affect it in the equation.

Wayne

$750 sounds :crazy: steep for that, better off getting a chassis dyno for less than half.

MotorHead

The dyno was expensive but this was an expensive shop in the first place, but they do good work and stand behind it blah blah blah. Anyway the price is basically labour setup, timkering and so on 100 bucks and hour for an builder with 30 + years experience and you get the idea.

Chassis dyno is less 1/10th price at 50 bucks, no brainer which one people are going to pick. Also alot of people worry about revving the motor out when you just spent 5 grand onit but if the motor is built right you break the cam in and let er rip and it should fine. :D

JRD77VET

First, a little common sense. :yesnod:

Before you put you car on the dyno, make sure the oil is fresh and full. Coolant at proper ratio and topped off. Check your tranny fluid and rear fluid also. Look over radiator hoses too.

Basic overview
You will put your car on the dyno. They will strap it down. You will start the car and go thru the gears until you are in DRIVE for a auto or 4th ( 1:1 ratio) for a manual.

At his command or signal, you will then give full throttle and take it up YOUR redline. Let off the gas and DO NOT HIT THE BRAKES !!!! Let it coast down and push in the clutch / put it in neutral. The dyno has it's own brakes.

Hitting the brakes on the dyno will damage it and the owner may beat you severely for damaging his $40K machine :eek:

While on the dyno, keep an eye on your gauges,ie.. oil pressure and temperature.

:thumbs: Have fun

:seeya Jeff

ORVette

Thanks Jeff. Will I need to disconnect my kickdown to prevent downshifting when I nail it? :cheers:

JRD77VET

I'm not sure :confused: Ask the guy if you should. I've only been around manual trans cars on the dyno.

I help with SCCA Touring 1 Corvette C5's. You can only run manual trans in the class. I do know that with a '02 Z06 in race trim ( no mufflers, 7500 redline . stock motor with race gas) 4 th gear at 7500 rpm equates to 165mph in 4th gear :D on the dyno.

:seeya Jeff

{edit} added "on the dyno"


[Modified by JRD77VET, 10:12 PM 8/16/2003]

ddecart

$750? That's more than I spent on the rebuild of my engine. Granted it was a refresh and not a major overhaul, but still. That's STEEP compared to the $50 for 3 dyno pulls on a chassis dyno.

MotorHead

$750 might be high but let's take a look at what they do and how long it will take.
Any engine builder/tuner that has a dyno has to be charging 76-100 bucks an hour for the shop/dyno and their time.

The engine is rebuilt and now it has to be prepped to put on the dyno that means adding all the parts that are nessessary for it to run, carb, fuel line, water hoses and the different sensors/gauges needed. All this takes time, 1-2 hours and it not even running yet. 1/2 hour for cam break in then let it cool down, now you make some dyno pulls and then they look at the data to see if the motor is running properly and if not make adjustments to carb, plugs etc.
Afer they have to take it off the dyno.

As you can see it takes time and time is money so $750 is not out of the ballpark

ddecart

I suppose the fairness of that price depends on what you're getting for the $750. If they're doing some fine tuning to get more power out, then that's one thing. If they're just hooking it up to see how it's set up, that's another. I'd consider paying a good bit to have someone spend some time with my car and squeeze some good power out of it.

Pete79L82

I was more reffering to dyno time to break the motor in and make sure every thing is working properly. We charge $275.00 to mount the motor up, break in the cam, reset the valves and make a couple of pull to set timing and carb. Nothing fancy, just make sure the motor makes the power it should and everything is working properly. If you want to continue on from there then it becomes time and materials. But it give the owner peice of mind that everything is right when you put it in the car.
I see so many times that someone puts in a new motor and fight to get it to even start and I cringe at what it is doing to the new cam and bearings when he has to keep cranking on it to get fuel or to get it to quit popping back through the carb. Or you put it in the car and it doesn't make the power you think it should. Now is it something in the car or something in the motor? Dynoing first takes all those questions out of the way.

I had a 383 on Thursday that a customer built himself. Warmed it up and checked everything over and made a pull at 502 HP. Did some tuning on it and 2 hours later I had it up to 528 HP. The customer felt it was the best $275.00 he ever spent.


A chassis dyno is fine and a great tool. The problem is that once the motor is in the car it is much harder to work on and make changes. It is much easier to make a cam change or cam timing change on an engine dyno than in the car.


Pete

Matt Gruber

Pete makes a good point about a novice with the distributor in wrong trying to break in the cam when it won't start and flames come out of the carb! :lol:
But is THAT guy going to pay $275?
And how does anyone get the engine to the shop?
I put the block in my 67 galaxie to take to the machine shop, but i don't want the entire engine in the trunk.
Most guys here that are after the last 20 HP get a G-tech. Costs less and is way more fun. Some fast cars jerk fuel in 1st to the rear cyl., that will not show up on the dyno.

mrvette

I don't know why particularly, but every engine I have ever had built, i'ts just the short block, all nice and pretty, and usually, but not allways, someone else does the head work, because I"m grinding and polishing the casting while the short block is being built....heads at the head shop, and then the combo get in at more or less one time....I usually put the SB in the car then do the heads....dunno why, just used to it that way...makes bellhousings/etc much easier....I know it's clumsey to torque head bolts, but that's only an hour's work...BFD.....lately the super PIA is the TPI systems, never did get away from that setup, but what with the way it's done, there is a reason for the madness....lazyness!!!!

GENE :eek: :eek: :lolg: