Low compression w/ 35cc domes

[Mike W]

I have been having a hard time getting my 44's tuned and was a little concerned about any damage I did during the process so I checked the compression yesturday. I mainly wanted to rule out low compression as a reason for my tuning difficulties. I have 35cc domes and I only have 170 psi in each cylinder. It is supposed to be closer to 185 if I'm not mistaken. My cylinders have stock porting so there is no reason for the compression to be that low. The fact that compression is dead even makes me think nothing is wrong there. Anyway, I pulled the head yesturday and noticed some scoring but nothing major. Anyone else run into the same issue?

 

[Matt_E]

There's nothing wrong. Your gauge is probably off.

Also, in high heat & humidity (FL?), the compression will be lower.

 

[Mike W]

Thats what I figured. The gauge I have is an el cheapo from Auto Zone.

 

[subnsxr]

I have 24cc domes on my SXR and my cheapo gage read 180 when actually it was 205.

 

[Mike W]

Mine is a $25 gauge. You get what you pay for I guess.

 

[Gainera2582]

Get this if you do not want to spend an arm and a leg for a snap-on and still have a good quality compression gauge:
http://www.sears.com/shc/s/p_10153_12605_00947089000P?vName=Tools&keyword=compresion+tester


Most accurate I have found compared to the actron and other el cheapo gauges I have used in the past.

 

[Mike W]

That is the one I intended on buying but keep forgetting every time I go to sears.

 

[Mark44]

What is your squish?

Mark44

 

[sjetrider]

What type of compression GA and are you using the long tip plug side connector and not the one for the stock head on your GA.???

I have been having a hard time getting my 44's tuned and was a little concerned about any damage I did during the process so I checked the compression yesturday. I mainly wanted to rule out low compression as a reason for my tuning difficulties. I have 35cc domes and I only have 170 psi in each cylinder. It is supposed to be closer to 185 if I'm not mistaken. My cylinders have stock porting so there is no reason for the compression to be that low. The fact that compression is dead even makes me think nothing is wrong there. Anyway, I pulled the head yesturday and noticed some scoring but nothing major. Anyone else run into the same issue?

 

[Jameski]

Im using 35cc domes as well and my compression test was 170psi also. Checked with another gauge at it read 165psi. have lifted the head and had a look and everything looks ok.

 

[Mike W]

What is your squish?

Mark44

Dont know. I never measured it. Not sure how to come to think of it.

What type of compression GA and are you using the long tip plug side connector and not the one for the stock head on your GA.???

Some off the wall brand from Auto Zone. I am using the extended adapter as well.

 

[Keith]

I have that same compression guage from craftsman. Compared it back to back with a snap-on guage. The difference between the two was only a couple of psi.

Remember you are looking for the cylinders to have the same or close to the same compression. The actual number isnt really important unless it is really different. Say you got 180 on one and 120 on the other then you probably have a problem.