compression

trucker3495

New member
Where can I buy a cheap timing degree wheel that fits clone? Can I use a regular 12 volt automotive timing light to check timing?
 

polartx

Member
Cheapest way to get a degree wheel is just to print one off online ( simple google search).
Then glue it to a piece of cardboard or I use a piece from a case of pop. 12 v timing light will work good.
 
The important thing about doing a compression test is not how high it is, but if it changes. You say the last test you did showed only 60 lbs., well if the next time you do it it only shows 50 lbs., you’ll know something is going bad. It’s quick and easy.
I can see the advantages of doing a leak down test, but the compression test is so fast and easy, and it can save you a lot of time. I don’t know, but I wonder, is there time to do a leak down test between heats?
So if you do the quick and easy compression test, and it’s down, you know for sure it’s the rings or the valves, so when you get home, you check with the leak down tester
Listen, if you go out in the first heat and you’re slow, you want to know why, right? A quick compression test will tell you right away if you’re down on compression, maybe not if it’s the rings or the valves, but it will tell you.
So right away, if you do a “quick” compression check, and if it’s not down at all, you know it’s not either one. Very quickly you have found you may have some other problem.

Comments, Complements, Criticisms and Questions are always welcome.
 

sCREamnClones

New member
The important thing about doing a compression test is not how high it is, but if it changes. You say the last test you did showed only 60 lbs., well if the next time you do it it only shows 50 lbs., you’ll know something is going bad. It’s quick and easy.
I can see the advantages of doing a leak down test, but the compression test is so fast and easy, and it can save you a lot of time. I don’t know, but I wonder, is there time to do a leak down test between heats?
So if you do the quick and easy compression test, and it’s down, you know for sure it’s the rings or the valves, so when you get home, you check with the leak down tester
Listen, if you go out in the first heat and you’re slow, you want to know why, right? A quick compression test will tell you right away if you’re down on compression, maybe not if it’s the rings or the valves, but it will tell you.
So right away, if you do a “quick” compression check, and if it’s not down at all, you know it’s not either one. Very quickly you have found you may have some other problem.

Comments, Complements, Criticisms and Questions are always welcome.
ou
I 'Complement' you AL! (I'm gonna take up a collection and buy you a L-D tester!) :)
 
In any engine with a compression release, a change in compression numbers from one day to the next is of little to no value. A simple change in valve lash settings will change the compression numbers. A change from 60lbs to 50lbs may mean the rings are worn or a valve is leaking or a head gasket is leaking OR that your running a few thousanths less lash and the engine is fine. Sure a compression test is fast and easy but with the compression release it offers very little useful information.
 
ou
I 'Complement' you AL! (I'm gonna take up a collection and buy you a L-D tester!) :)
Thank you for the offer. What is an L-D tester?
I have no engines, it would be a total waste of money.

Comments, Complements, Criticisms and Questions are always welcome.
 

RadialFin

New member
What if you whip off the side cover and spin it over with a starter at 1500 RPM
 

astrowrench

New member
1500 rpm would take the compression release out of the picture..Yes...Then we have other factors,such as the fuel and air mix, BIG- BANG that happens when the spark plug fires; Thus creating different cylinder pressures Leak down test is the best way; and they are easily and cheaply built.
 

DD racing

New member
when doing a leak down test what is a good
% to look for on a new engine ? i know im not realy going to get 0% is
 

astrowrench

New member
If you get better than 12% leakdown your in pretty good shape This all depends on what pressure your testing at
 

Kart43

Member
@100psi we shoot for 2% leakage at 4 we evaluate, if anything is heard at the valve regardless of guage reading I fix it. All guages are different but if I saw 12% on mine the engine came from a junk yard.
 
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