how to measure timing numbers

[Rick Sowell]

I know this has been discussed probably many times but I can't find it in a search, how do I go about measuring my motors timing, in paticular the exhaust timing. I have all the degree wheels and dial indicators and calipers to measure with, so what are the best methods for doing this. Thanks in advance.

 

[mark voorhies]

There are a few ways to measure timings, but to keep it simple is to have the Engine Program from Marty Davis.

Then you only have to have some basic measuring tools to get your timings.

http://engine-analysis-software.com/

 

[Rick Sowell]

well I guess this must be a top secret topic, and I will have to spend $100 on software that I don't need to get the information I need.

 

[BB Mods's]

If you don't want the best engine building software they make, then go grab your degree wheel and do it the old fashioned way, Just make sure to check your numbers 8~10 times b4 you start cutting, Marty's way is the best and only way to measure/change your engine timing.

 

[Terry Keeley]

 

[Jerry Wyss]

sorry about the screwed up pic, but it shows a makeshift part

 

[Daniel's Racing]

You will be so much better off with a good old degree wheel. Those engine programs require you to input a lot of info and measurements some of which are not at all easy to take. Then there is still so much room for error. Degree wheel simple as watching the piston and noting the degrees on wheel and some addition and subtraction and it is very accurate.

For exhaust duration you dont even have to find top dead center. Mount the wheel anywhere and note the degree that the piston clears the roof of the port he way down and keep turning in the same direction till it comes back up and is just closing, the degrees the wheel turned is your exhaust duration.

Daniel

 

[camaroboy383]

rick,,, set up your degree wheel so when the engine is at tdc the pointer points to 0.. rotate in normal operation direction and record the degree the port opens and closes at...thats why its some what different from person to person and thats why its important to check a bunch of times,,end plays will mess with you more times than not... it will give you a idea of where you are at...

alden

 

[mark voorhies]

If you don't want the best engine building software they make, then go grab your degree wheel and do it the old fashioned way, Just make sure to check your numbers 8~10 times b4 you start cutting, Marty's way is the best and only way to measure/change your engine timing.

Also comp. ratio is major important, hard to get that right without playin with numbers on a program.

 

[Norm Doerr]

I cannot comprehend how a degree wheel would be a reliable method to measure an engine. It is one way to do it, and more economical but NOT the best way. We have literally measured, cut, cleaned and reassembled as many as 10 engines on a single Saturday with the EAP and the information is solid enough to share with other EAP users There are to many variables using a degree wheel, including the wheel itself. Not to mention what you use as a cursor, slop in the rod, bearings, wrist pin, how you hold your tongue, you name it. Anytime you measure off the crank you have to deal with a larger margin of error. Next thing will be how to use a dremel tool to make perfect cuts on a sleeve... If a degree wheel is all you have and or prefer to use that is fine, a lot of modelers still go that route; but please don't downplay a tried and proven superior tool. Ask any of the accomplished engine builders, what they use. Two out of three are useing the EAP, and I can bet anyone using a degree wheel has a purpose built tool NOT one designed to build four stroke car engines.

Norm Doerr

 

[Geraghty]

well I guess this must be a top secret topic, and I will have to spend $100 on software that I don't need to get the information I need.

http://www.mh-aerotools.de/airfoils/hdi_enginetiming.htm

 

[Rick Sowell]

Thanks Rod and everyone else, this will help me to find and modify my motors timing numbers. Rick