I own a 87 camaro w/ a 2.8L engine. I recently had head gasket problems. I replaced the head gaskets, re-assembled the top half and fired it up...or I tried to anyway.

SYMPTOMS:
-Very very hard to start but, will start if given enough patience.
-When running It lacks serious power in gear but, idles fine.
-Hear I very slight vacuum leak from somewhere but, I cannot pinpoint it.

ACTIONS TAKEN:
-Compression test comes to 125 p.s.i. in all 6 cylinders
(seems normal. been that way since day one)
-Checked timing
(Timing is on mark)
-Disassembled front of engine to check timing marks.
(marks are aligned)
-When I was replacing the head gasket I inspected the valve seats and heads as well as top of cylinders.
(No cracks or warped valves and comp. test readings confirm with uniformity)
-pulled vacuum test.
(read 5 and slowly dropped to 0. When accelerated the reading rises. When rpm's are maintained, reading begins to fall to 0 again.)

MY ASSESSMENT:
Now I may be wrong here in assuming this and that is why I am asking for other opinions but, I think that according to the vacuum reading I may have a choked up muffler. Someone call me on this if I'm wrong but, if you have a choked muffler you will still get exhaust flow from it but, it won't be good flow. And I think it may be possible that If I was blowing oil-mixed coolant out of my tailpipe due to a bad head gasket, Couldn't it goo something up like my catalytic converter or my muffler? I would like to get another opinion on this before I go hacking up my exhaust system.

Thanx in advance

 

it's possible the cat got tosted. They don't stand up to oil and stuff.

I would definetly go after that vaccum leak. It may be worse then you think. The two combined could be making things worse.

 

to be honest it sounds like the vac. leak is coming from the back of the intake under the plenums. Those "pro's" at fel-pro put RTV in the gasket set for the front and rear intake seals. Maybe that's what you're supposed to use though because I had to scrape off the old RTV that was there. Anyway, I thought I put a pretty swollen beed of RTV on there to seal it. Maybe I caught an air pocket. won't stay running long enough for my to find it. But, it definately does not sound like a hose leak. Not a very high pitched hiss. Sounds more like the hiss of your vacuum cleaner when it's on carpet. I think I will chop off the cat to see if it changes anything. In the meantime I would appreciate anymore help you guys/girls can give. I will keep you all posted.

Thanx

 

Yep, that's why Fel Pro is the best. Gaskets don't hold up well in those spots; they're not machined perfectly; RTV can take up the gaps. I use ultra-copper RTV for the china walls. Read about it here: https://www.thirdgen.org/techbb2/sho...hreadid=169330

 

You're right. Gm was kinda shoddy with machining the 2.8 and 3.1. Seems to me they paid more attention to the 3.8. stronger castings and everything on that block. You can tell when you drive these engines, which one had more TLC, and it wasn't the 2.8 or 3.1. And yes Permatex Copper works for everything. lol. Can withstand 700 F. Great for exhaust.

 

just checking to see if I got my sig the way I want it. Didn't want to corrupt someone elses post. (still learning how to really use this site.)

 

ultra-copper RTV rocks. I use it on everything. Of course you gotta use it right and not go nuts. I also like a product called seal all. In a yellow nd red tube n package. It is great as it is gas proof.

Matt

 

I don't know what kind of compression these V6's run anymore...but 125 seems awfully low to me. I'd think that more around 150-160 would be normal.

 

that's what I've been hearing but, I brought it to school when I first got this engine (rebuilt) and I'm pretty sure it tested 125p.s.i. But, what would cause a low reading in all cylinders like that? Is that another sign of an exhaust obstruction?

 

if all your cylinders were reading that low compression, and they were all pretty close to the same numbers i doubt u have a problem.... although, i've heard that they're normally around the 160 mark, maybe 150 on older motors. W/ my new engine it was tested at 170 i believe in all cylinders. If you're compression is dropping , there are ways to see where it'coming from, you have to listen to the motor while the air's compressed. Listen to the oil dipstick area, if you hear air comingthrough the dipstick tube then your rings are worn and the engine is losing compression through the rings which is letting air to the oil pan and you'll hear it throug the oil stick. Way two is to listen from your intake, if you can hear air coming through the intake, then some intake valve isn't seating properly and causing the loss of air through the intake , and despite how difficult it'd be, the last would be through the exhaust, but i doubt that we'd be able to hear the ehaust with as much piping and baffeling we have through ours, (works great on the airplanes though) , if you hear something through the pipes then it's coming from your exhaust valve not seating properly.

 

I did my compression test a lonnng time ago, around 2000 I guess... I think that was around the timing chain change, so it would've been 180,000 miles. Anyway, I was between 140-160 psi on 5 cylinders, and the #1 came out at 125. (That's the cylinder that killed the spark plug due to detonation, the rings probably took a good hit.) I don't think an exhaust restriction would cause a low compression test; you're measuring the compression in the cylinder before it even reaches the exhaust.

Have you tried unhooking the cat? Or even disconnecting the I-pipe from the back of the cat (might need a lot of liquid wrench to do that)?

 

Thanx for your help but, all you had to do is tell me to pull a cylinder leak-down test. LOL.
I'm gonna go chop my cat off right now...I'll post it later and tell you if anything has changed.

 

to use such small words isn't fun, much better to draw it out good luck with it.

 

maybe leaking intake manifold, could be a clogged exhaust...maybe fuel pressure

 

Okay here's the latest...I didn't chop the cat because there was an ample amount of exhaust flow way too much flow for there to be a clog. I pulled another vacuum using a new gauge and I am pulling about 15 in. and it is steady with no fluctuations or or decline at all. I found the vac. leak. it is down in the intake area. most likely on the fuel rail. I will not be tearing it apart to find out though because I decided to change the oil again because i noticed it was still a little milky so I double checked my antifreeze to make sure it wasn't still leaking. It's not. after changing the oil the motor has developed what sounds like a wristpin knock. It's really loud and is not leaving any shavings in the new oil. I drove it 10 miles around town today and it stayed consistent, did not die, but, did start to overheat. Yet, still no shavings. This one is done guys. thanx for all your help. This motor was rebuilt by RECON, 18,000 ago. I will not invest anymore money into this car. let someone else take it for parts or a beater or something. My RS needs my full undivided attention right now and I have no more time, money or patience for this car. Check the classifieds. The silver bullet will be there.

P.S. Recon has decided to back out of the extended warranty I bought and paid for. Only 15 mos. ago. It was supposed to cover things such as this mishap for an additional 15 mos after the first 15 mos. but, they first tried the excuse that a head gasket can go bad at anytime and that falls under workmanship which is only covered for the first 15 days. I remind you that this hread gasket was warped not cracked and the only time I have seen a headgasket warp was when someone didn't torque it down in the right sequence. Next they told me to take it to a shop and have it assessed. (they wouldn't let me do it myself) Because the mechanic started disassembly without "approval" they weaseled out of the warranty. Regardless af what happened to me, I would advise that noone buy from RECON. Bottom line is that they built an engine that only lasted 18k miles. Poor quality in my opinion.