compression tester

[James McDowell]

I"m going to do a compression test on the 51 8n this weekend to see if it needs a head gasket. I read in the 50 tips that you can use a brass elbow to make it easier to get the compression tester in there. Does anyone know what size elbow I should ask for at the plumbing supply? I appreciate the help.

 

[JMOR]

There isn't a commercial pipe thread that matches the spark plug. Someone may sell a right angle adapter, but I wouldn't know, nor where to find it if they did. I made mine quicker than I could have went anywhere to a store as shown.

 

[Dell (WA)]

James.......amazingly enuff, yer N-sparkies are 14mm, thats right METRIC. Plumbing ain't metric. And yer right, them rubber cone compression gauges don't turn a corner very well. I have a rubber-hoze screw-in compression gauge that turns the corner and fits under the gastank. Most engine sparkie holes are a "straight shot" and don't need right-angles adapters. ......Dell

 

[MR in MN]

Make life easy on yourself and buy one of these.

 

[Hobo,NC]

I been doing it the hard way for 35 years,,, I look for water in the spark plug hole

You have a 1/1000 chance that a compression test will find a leaking head gasket

Even if you do see a cylinder down on compression that does not indicate a head gasket problem

Checking for a coolant leak is probably the least understood process I have seen here,,, does sell a lot of head gaskets,,, does make the backyard Bob think he's do'n good

 

[Bruce (VA)]

You will have a hard time getting an elbow to fit the plug hole because they are 14mm straight thread. My compression gauge came with two adapters. One is 14mm straight thread which fits the N & the other is, I think, 18mm. You screw the correct adapter in the head & the hose goes into the adapter. But, to make it easier, I took the 14mm adapter to the plumbing counter in the hardware store & found a brass elbow that fit the adapter on one side & the hose on the other. Now, I just screw the 14mm adapter into the head w/ the elbow already on it then screw the hose into the elbow. But, if you can find an elbow w/ 14mm straight threads on one side, you save a step.
50 Tips

 

[JMOR]

(quoted from post at 07:40:43 03/24/09)
I been doing it the hard way for 35 years,,, I look for water in the spark plug hole

You have a 1/1000 chance that a compression test will find a leaking head gasket

Even if you do see a cylinder down on compression that does not indicate a head gasket problem

Checking for a coolant leak is probably the least understood process I have seen here,,, does sell a lot of head gaskets,,, does make the backyard Bob think he's do'n good

I have thought for a long time that there are reports of a very high incidence of head gasket replacements. Hobo, is there a major weakness in the N or do you figure many are shot in the dark unnecessary replacements?

 

[Hobo,NC]

(quoted from post at 15:47:01 03/24/09)

(quoted from post at 07:40:43 03/24/09)
I been doing it the hard way for 35 years,,, I look for water in the spark plug hole

You have a 1/1000 chance that a compression test will find a leaking head gasket

Even if you do see a cylinder down on compression that does not indicate a head gasket problem

Checking for a coolant leak is probably the least understood process I have seen here,,, does sell a lot of head gaskets,,, does make the backyard Bob think he's do'n good

I have thought for a long time that there are reports of a very high incidence of head gasket replacements. Hobo, is there a major weakness in the N or do you figure many are shot in the dark unnecessary replacements?

The poor head gasket,,, it gets the blame for every engine problem,,, must B a miracle fix cuzz its always to blame and always the recommended fix,,, I would not throw another dollar at it but if you gotta mite as well put 2 of'em on it,,, if ones good then 2's gotta B better

Its a miracle cure with no battle plan,,, these boys would stave to death working on commission

Most need to think before thay react :lol:

I think I will sell off my N's ,,, I don't need a tractor that eats head gaskets :twisted:

 

[James McDowell]

I"m not sure what you mean about water in the sparkplug hole. Should I look for moisture when I pull the plug out or will it accumulate in the depression in the head around where that sparkplug screws in? Thanks for the advice.

 

[Greg_Ky]

I would do a leak down test, at least it will tell you where the problem is: rings, valves, head gasket.

 

[James McDowell]

I"m not familiar with that. What exactly is a leak-down test?

 

[Greg_Ky]

James follow the link for a quick explanation. you can also use the hose from a compression tester and just hook it up to an air hose and listen for leakage.
Leak down test.

 

[Anonymous-0]

JMOR,
I saw the picture of your homemade adaptor for
a compression guage. I plan on making my own
but tell me what is an anti-fouler that you used
on one end??

 

[jon]

I plan on making my own but tell me what is an anti-fouler that you used on one end??

They're used to screw your plug in & then screw it in your plug hole for oil burning engines. Raises the plug away from the oil I guess. Just ask any parts guy for Anti-Foulers". They'll know whatcha mean.

 

[JMOR]

(quoted from post at 19:41:59 03/26/09)

I plan on making my own but tell me what is an anti-fouler that you used on one end??

They're used to screw your plug in & then screw it in your plug hole for oil burning engines. Raises the plug away from the oil I guess. Just ask any parts guy for Anti-Foulers". They'll know whatcha mean.

That's right. Lengthens the heat transfer path and makes the plug run hotter than 9 kinds of Hades! Also, it only has a small hole in it and does shield the electrodes, but I think running nearly red hot is the biggie.
Another temporary band-aid.