Did a compression check tonight. The spec is 218psi. Cylinder 1 & 2 checked out perfect at 218psi, 3 was at 215, and 4 was at 205. Added a little oil to cyl 4 and it went back up to spec, so I think I have a small ring problem on cylinder 4. Any thoughts?
__________________
Never run out of real estate, traction & ideas at the same time.
2007 Tacoma 2wd 4cyl 5spd reg cab
1998 Accent L - #13 FSP SCCA Solo2 in 2005, SOLD
2001 Accent GS - RIP
Compression will vary slightly, even with new engines. Cyls 1-3 are within spec according to my book. Cyl 4 might have a leak somewhere. The pressure should not vary more than 5-7 pounds. The first place (and easiest) I would check is the head gasket. It might have a small leak. The second would be valve seals and the third would be rings.
I would yank the head (under warranty?) and visually inspect the head gasket. If it is that; which is likely, I'd have the head machined and checked for leaks by magna fluxing it.
The main issue with our engines is the aluminum head. It can warp and crack very easily. Keeping the cooling system in perfect condition is required for it to last. These heads do have a tendency to pop head gaskets easily.
I also called a friend who runs the school district vehicle shop on the subject as well. I have him the numbers and he told me it "could" be a bad valve. Further conversation with him on my suggestions would be exactly what I said above.
According to what i've read, and what HMA says, the car is within spec. :ermm: Also, i've read that if the compression comes back up when you add a little oil into the cylinder, its a ring problem. Why? The oil goes down and makes the rings seal. If the car checks out fine, then it cant be the head gasket nor the valves as the oil wouldnt get that high.
But yeah, the HMA standard is 14psi between cylinders, and a minimum of 203psi. So no warranty workfor me, though i'm gonna ask monday when I go in to bitch about something else.
__________________
Never run out of real estate, traction & ideas at the same time.
2007 Tacoma 2wd 4cyl 5spd reg cab
1998 Accent L - #13 FSP SCCA Solo2 in 2005, SOLD
2001 Accent GS - RIP
Originally posted by skierd
[body]
According to what i've read, and what HMA says, the car is within spec. :ermm: Also, i've read that if the compression comes back up when you add a little oil into the cylinder, its a ring problem. Why? The oil goes down and makes the rings seal. If the car checks out fine, then it cant be the head gasket nor the valves as the oil wouldnt get that high.
But yeah, the HMA standard is 14psi between cylinders, and a minimum of 203psi. So no warranty workfor me, though i'm gonna ask monday when I go in to bitch about something else.
[/body]
However, the 203 low pressure is low enough to cause problems when the other 3 are 215-218; performance wise.
John, my friend with the school district garage said to check the valve seals and valves, even though it could be within the 10% factor. On a high performance engine, a variance of 7 pounds makes a big difference in the durability of the engine. Leakage is an issue big time. Another experienced (50 year with ase cert.) mechanic I know also said that it may be within spec, but on a high revving engine, that low cylindar can blow very easily.
Personnally, I wouldn't let my engine vary 7 pounds between cylindars. If you have a turbo or supercharger, having the cylindar pressure equal to one another is essential because the engine could blow a valve or ring set (plus head gaskets and/or cracking a head).
On my next service call, I'm going to have an aux trans cooler installed and ask about a second radiator fan (my car has 1 fan now). I am thinking of adding the second fan as insurance for overheating issues if I decide to beef up the stock engine. I could go ahead and yank the engine/trans and stuff a 2 liter Elantra GT motor and trans in the car if I wanted to.
i dont think it can be the valve seats or the gasket. dave said he added oil and after that compression went up.......that has so be the ring since oil helps seal space around the rings only
it cant really get up to the valve or gasket(at least not eough to make a differnce in compression)
Originally posted by skierd
[body]
According to what i've read, and what HMA says, the car is within spec. :ermm: Also, i've read that if the compression comes back up when you add a little oil into the cylinder, its a ring problem. Why? The oil goes down and makes the rings seal. If the car checks out fine, then it cant be the head gasket nor the valves as the oil wouldnt get that high.
But yeah, the HMA standard is 14psi between cylinders, and a minimum of 203psi. So no warranty workfor me, though i'm gonna ask monday when I go in to bitch about something else.
[/body]
However, the 203 low pressure is low enough to cause problems when the other 3 are 215-218; performance wise.
John, my friend with the school district garage said to check the valve seals and valves, even though it could be within the 10% factor. On a high performance engine, a variance of 7 pounds makes a big difference in the durability of the engine. Leakage is an issue big time. Another experienced (50 year with ase cert.) mechanic I know also said that it may be within spec, but on a high revving engine, that low cylindar can blow very easily.
Personnally, I wouldn't let my engine vary 7 pounds between cylindars. If you have a turbo or supercharger, having the cylindar pressure equal to one another is essential because the engine could blow a valve or ring set (plus head gaskets and/or cracking a head).
On my next service call, I'm going to have an aux trans cooler installed and ask about a second radiator fan (my car has 1 fan now). I am thinking of adding the second fan as insurance for overheating issues if I decide to beef up the stock engine. I could go ahead and yank the engine/trans and stuff a 2 liter Elantra GT motor and trans in the car if I wanted to.
[/body]
this is true
but guess what
Its a hyundai engine not a high revving perfromance engine.
and its within hyundai spec....so it wont be warranty replaced, no matter what some other ASE cert tech says.
Thou it may fuck up a HIGH boost turbo motor or VERY Higher revving n/a motor.
the alpha only goes to 6500 not very high at all. so I am sure the difference wont cause any problems.
__________________
*My Hyundai sense is tingling!*
"Awwww! Gawd damn! My "H" is gone, Whats the point of owning a Hyundai if ya cant show it off?
Kore Crew #4
Jezz, 218 psi?? My Turbo Sunbird runs at 160 psi!! And this is within factory spec!
218 psi just sounds high to me. But I am used to old school domestic motors and I suppose it is within factory spec so............
__________________
old car; 2002 Accent GS 5 speed
custom 3" cold air intake
custom 2" cat back exhaust
Dynomax Super Turbo muffler
10 mpg on the race track
53,105 miles as of 06-29-03
90 hp and 95 ft lbs at the wheels
New car; 2003 Dodge SRT-4
13.6 @ 104 mph, not stock!!
Originally posted by 91cavgt
[body]
Jezz, 218 psi?? My Turbo Sunbird runs at 160 psi!! And this is within factory spec!
218 psi just sounds high to me. But I am used to old school domestic motors and I suppose it is within factory spec so............
[/body]
you are also comparing a n/a motor with 10:1 compression to a turbo motor, which probably has 8:1 or 7:1 compression.
__________________
*My Hyundai sense is tingling!*
"Awwww! Gawd damn! My "H" is gone, Whats the point of owning a Hyundai if ya cant show it off?
Kore Crew #4
AutoForums.com is the premier network of enthusiast-owned
enthusiast-operated automotive communities.
We operate more than 100 automotive forums where our users consult peers for shopping information and advice, and share
experiences and opinions as a community.
Compression check...
Linear Mode
