Well, I have the 8.6:1 JE pistons. I did the test right after driving her for a bit. Here are the results: 160 160 152 165. Is my head gasket fucked or what??? I did this so I could figure out if the head gasket is the culprit behind all my overheating problems. What are my numbers supposed to be at??? I never did a test after the rebuild , so these are my first numbers. Thanks guys.....(keeping fingers crossed!)

Do you see bubbles in your coolant? It doesn't have to mix with oil to be a blown HG. I'd do a leakdown if you're not sure what your numbers are supposed to be.

Shit is all apart. Typical...

you have to remember that you are running lower compression pistons so your compression will be lower...175-185 is pretty normal/good with stock pistons so I would say you are probably ok since you are running lower compression pistons. Just for the info...my/my dad's 69 vette runs 360 compression and takes 96 octane gas

2003 Acura RSX Type-S
15.042 @ 93.06
Devon
Creator of one of the longest and most controversial posts in 2gnt history...
http://forums.2gnt.com/dcboard.php?az=show_topic&forum=38&topic_id=112462&mesg_id=112462&page=

i'd say those numbers are a little low, unless they are when the engine was cold. but he siad that he did it right after a run. Mine where about 180 across the board (+ - 1 or 2). Hope its just your headgasket dude

http://home.bendcable.com/optimuspeterson <<<<HRC Stage 2 and Star Instructions
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2006 Scion tC

I think those may be somewhat low, but all the numbers are pretty close, I wouldnt think that a blown HG is the culprit. As far as stock compression, if any of your cylinders are like that when warm you have a problem. My compression was 220-220-225-220 and that was with a leaky tester.

Toney
'97 RS 5 Speed (totaled)
15.4606@88.42 Mph
96 Toyota Celica GT
88 Toyota Supra NA-T (w/ sports package)
Got Boost?? Hell yeah I-6 turbo powah baby!

Yeah, my engine was right up to normal temp when I did the test. I have VERY minimal blow-by(barely any), and I don't puff any smoke....only when my car first goes into boost, it shoots out a black puff of smoke, then fine all the way to redline. The only problem I've been having lately has been the overheating....because my car is spewing out antifreeze when I boost it hard in 3rd and 4th gear. Looks like it may not turn out to be the radiator after all

Anybody else?? Need some more help here..

'00 Harley-Davidson F150
'88 Mustang GT
'93 Mustang LX 5.0
'00 Focus (beater)

TTT...anyone else??

'00 Harley-Davidson F150
'88 Mustang GT
'93 Mustang LX 5.0
'00 Focus (beater)

ANYONE???

'00 Harley-Davidson F150
'88 Mustang GT
'93 Mustang LX 5.0
'00 Focus (beater)

Well I'm no expert at compression tests but I wouldn't go searching for a blown H/G just yet. I believe that if it's 15% lower in 2 cylenders is when you have to search for that. When you rebuilt the motor did you use the MLS HG. I could be really wrong here but if your HG was leaking enough to make you overheat I think you would deff. see some oil in coolant or vice versa. What about heater cores lower radiator hoses have you checked all of these things? I havn't checked that stuff on mine but my overheating seems to be caused by the A/C being on. Any ideas on where I should look into?

I edited to the wiki!

My car overheated this past weekend and it was due to a blown upper radiator hose. Im sure you have checked your hoses by now, but the only way I could tell that that was what it was with the hose on the car was when steam was shooting out the crack since it was really small. I also had coolant all over my engine bay, hell when I opened my hood some even got on my fender and bumper.

Toney
'97 RS 5 Speed (totaled)
15.4606@88.42 Mph
96 Toyota Celica GT
88 Toyota Supra NA-T (w/ sports package)
Got Boost?? Hell yeah I-6 turbo powah baby!

We mustn’t forget altitude plays a roll in your compression numbers. I have no clue why your car is over heating so I am not much help to you there. But I have 140 dead on all 4 cylinders w/ the same compression pistons as you. I drove up to ~10,000 feet awhile back and did a quick one cylinder compression test I got a whopping 120. On that same cylinder at my house ~5800ft I have 140. There are a lot of things that will make your compression differ. Not every car is going to have the same compression even if it has the same motor. Carbon buildup can cause your numbers to spike up a bit in a cylinder. Your head could have been resurfaced causing your compression to be higher. Headgaskets could be different size, etc, etc, etc.

The absolute best way to check your compression is to do a leak down. I would say if you have anything less than 10% leak you have no problems. Anything more and you many need to do some tarring apart and investigating.

Just my .02
Brian

my stock comp w/9.6:1 comp was ~170 cross the board... i wudn't worry at all w/your setup... uncross your fingaz already

03 srt-4 13.130@112.47mph (n2o, stock turbo, 10/2003)
now: 20g, portfueler, bpu+++ (track/dyno times tbd...)

i farted on your wiki

dang 170 sean! well here are my number stock engine: 145 130 130 140 haha if you number are around mine you better start worrying. I get mega lag. haha my friends 86 has more low end than me and they have no lowend. I did a compression test on my friend stock GST and he got 185 accross the cylinders if that helps. That's perfect compression for a GST. Chachi got nearly 215 across all cylinders in his stock RS.

http://www.hadesomega.info -car specz and movies 95 Eclipse RS | 76' 280Z | 89' MR2 | 99 Neon | 91 Zephyr
Who sez FF can't drift?

Thanks a bunch guys, just what I wanted to hear. Leakdown test is definitly in order next, just want to make sure my headgasket isn't the culprit. The reason my car is overheating, is because I piss out a lot of antifreeze as soon as I boost the car hard. Once I piss it out, then it overheats because I'm low on fluid. I've replace both hoses, the radiator cap, thermostat, and flushed the radiator out and nothing, it's only gotten worse the past week

If you drive the car with no boost does it still overheat?

Greg

'19 Genesis G70 3.3t AWD
'88 Chrysler Conquest TSI

It's fine if you just cruise off boost...as soon as you boost...it gets hot..mostly in 3rd and 4th gear..

'00 Harley-Davidson F150
'88 Mustang GT
'93 Mustang LX 5.0
'00 Focus (beater)

Well there has to be a reason that it's coming out. Does it come out through the overflow tank? Do you already know why it's spewing out? Is it just because it boils over? Is there anyway to check a heater core?

I edited to the wiki!

If I just cruise around off boost(or even say 5psi), then the car will not overheat. But when I boost it hard(spikes to 15psi, drops to 12psi), it overheats mostly in third or fourth gear like DSBLK93GT said. As far as where the antifreeze is coming from, it's overflowing out of my overflow tank dump tube.....I really am starting to suspect the headgasket. Mainly because it will only overheat if I boost it hard in the taller gears....what do you think Greg??

Here's what mine did.

Moderate boost driving to work. 15 miles freeway and surface streets. Overheated right after I got off the freeway. I looked at the gauge on minute and it was fine, 20 seconds later it was pegged.

Put in 1 liter of water and drove it home. NO boost. Never overheated and coolant was still full when I checked it later.

My headgasket was blown. The low cylinder compression was caused by the piston/cylinder wall damage caused by the plug coming apart (the plug also took out the hg). The excess cylinder pressure (read boost) pushed past the HG and into the water jacket. This pressure pushed the coolant out the path of least resistance - the radiator cap. Once the overflow bottle was full, the coolant just hit the ground.

Based on MY experiences of the last 2 weeks, I would change the headgasket (if it was my car). I can't guarantee that's the problem, but I'd put money on it. Go somwhere that has a leakdown tester and a BIG compressor, open the radiator cap, and put a couple hundred pounds of air in the cylinder. If the coolant starts bubbling, you know what you have to do....

Here's a pic of my HG with the "damage" circled. It doesn't take much. There were no physical defects other that being a little warped. The head had all the damage on it.

Greg

'19 Genesis G70 3.3t AWD
'88 Chrysler Conquest TSI

Well my overheating seems to be different from yours guys. Do you have any advice for me? My comp #'s are 205 / 205 / 210 / 210. and I only overheat when the A/C is on at highway speeds (60 or more). It never boils over out the overflow it just starts running real real hot. I've already replaced the thermostat 160 degree from howell. Got a cooling system flush. and I use water wetter. What should I look into?

I edited to the wiki!

Front mount IC? If so, you may not be getting enough air through the radiator at speed. Lots of the 4g63 guys have problems with this.

Greg

'19 Genesis G70 3.3t AWD
'88 Chrysler Conquest TSI

radiator and a/c fan coming on when they suppose to come on?

yep front mount. the fans come on when they are supposed to. So how can I fix it?

I edited to the wiki!

Try and get some more air to the radiator. Scoop, vent, something. Do a search on DSMTalk on overheating and see what those guys have done.

Greg

'19 Genesis G70 3.3t AWD
'88 Chrysler Conquest TSI