Blew up top end I think (1987 GN)

E

ericmccann

Member
Joined
Jun 6, 2008
I think I just blew up my motor. 79,000 original mile GN motor is now something of an uncertainty. During a race with a 1970 Chevelle from a gas station "hey, wanna race" guy, I whooped his ass immediately. Through the RPM range, I popped something and oil was spewing everywhere. Oil is all over the top of the motor and I thought I saw burning oil smoke from the exhaust. Got home - quickly (30 seconds or less), and noticed that the engine was missing (allthough I noticed this at the end of the race too). I then immediately shut it down. No knocks or anything that would indicate a bottom-end failure.

Lots of air is pushing through the oil fill spout (drivers side). The breather on the passenger side is soaked with oil as is the oil fill breather.

The fact that a lot of air is pushing through the oil fill spout means that I may have lost a valve guide and seal, but, I'm also noticing oil now in the intake tube off of the intercooler. Not a lot, just a little tiny bit of a slight oil film.

Still, I heard something on the top end pop. I'm moderately familiar with these motors, but not like you guys. Any thoughts as to what this may be? I'm not leaking coolant anywhere. Just oil everywhere on the top of the motor and the cylinder that's shooting air through the oil fill tube.

I live in Germantown, WI and REALLY need some good advice here. I just got this car literally a week ago and was afraid to let it run hard. Now I think I know why. What I need is some good, solid advice. I also need to find a GOOD machine shop and head parts source. I'm thinking that I need all new valves, guides and seals on the drivers side head. The oil spray on both sides is alarming though. Seems as the problem is mostly if not all on the drivers side head.

Should I have both heads re-worked? I can have the top end torn apart and ready for drop-off by tomorrow evening.

I'm afraid to tell my wife that I just blew up the motor - which is exactly what I just did.

ANY thoughts, suggestions and/or advice is VERY welcomed!

Thanks!

Eric McCann
Germantown, WI
eric.mccann@sbcglobal.net
414-708-1014 (Cell)
 
Dont freak out, ive blew my head gaskest more times than i care to remember. I dont know the condition of your car, but sounds like thats what you did. Anyway, pull both heads, have them checked, and worked besure to tell them you want new VALVE GUIDES!!! not just new valve seats, and if at all possible get new valves if those are old. 2nd, if you are not doing the work yourself, besure to buy the parts yourself, and take them to the ones doing the work, because they will pull none turbo parts in your car, so get gaskest, valves, and guides to take with you. 3rd, replace all your head bolts with ARP replacement bolts, or studs if you chose to do the studs. Look at our vendors list on main page, and find a vendor to get your parts. If oil and water is not mixing, you may be in good shape. If it is, and you shut it down soon as it happen, you may still be ok. Always run HIGH octain in thes car if your going to push them hard! fullthrottlespeed.com is a good vendor, and Gbodyparts.com for the price.
 
That would certainly account for the air coming through the oil filler tube. Thinking about it, this could be. The motor was nice and solid before this event so... I'll trear apart the top end and inspect.

I *felt* it go, and I know what that feels like based on my 1979 Buick Regal Sport Coupe (Turbo) go as well.

I'm just glad that I represented the GN in my town accordingly. I won hands-down, but at a huge cost.

I guess BOTH head gaskets are in order.

The BIG question is which head gaskets should I get?

Thanks!!!!

Eric
 
My car is actually a really nice example of a 1987 GN. Oil and water is not mixing. Just oil seeping through every outside orafice possible and misfire on a certain cylinder (or two). I think it's just one cylinder.

Who is a good quality parts resource here? Remember, I'm a complete noobie and am seriously asking for your best judgement on parts vendors. I love this car. It's everything I've ever wanted in a car. I just want to heal it.

Thanks everyone.

Best,

Eric McCann
Germantown, WI
 
Everyone has their own preference on headgaskets. For me the stock GM gaskets have never let me down.

For a good vendor, I've always had excellent service from Full Throttle.
 
Eric, don't put your cell online. Metacrawlers will pick this up and add it to a database, and you're going to be flooded with calls from people hawking extended warranties, snake oil, and everything else.

Sounds like head gaskets to me. Get in there and take a look at what's going on. I just went through this, as well. I had lots of sugg's for the stock GM gaskets and also the Felpro 9441's. I went with the felpro's so I don't have an opinion on these yet.

Nice job representin the peeps! :cool:
 
Look on the main page of this site, and go to vendors, they have all you need, i find that jegs.com has the best price on the new bolts. I would replace both sides. Also i like the stock head gaskets, for one the cometic ones leak on a friend of mines car, they say there bullet proof, but ive got great service out of the stock ones, and they seal the first time.
 
Hey, thanks for the suggestions. I already ordered the Cometic gaskets though and ARP head bolts for this little project. I should be on the road in relatively short order.

I've never ordered anything from Jegs before - since, well they never had anything I needed with my pre-GN italian car hobby. Now that I'm into the GN, jegs is probably a good resource. Thanks!

I blew up the Felcro head gaskets on my '79 turbo regal. Lasted about 10,000 miles, then boom. I agree that everyone likes their own brand of parts, etc. This time, I'm going to try the Cometic's.

Best,

Eric
 
ericmccann said:
Um, forgive my stupidity, but I have no idea what that means.
Click to expand...
"Caddy Pills" are crushed up walnut shells GM sells for some of their Aluminum headed engines to stop leaks due to casting holes in the Aluminum...works good for sealing all small gaps.
 
How fast is your car? My belief is that unless you're into the 10's there's no need to bother with cometics. The majority of headgaskets that pop at lower power levels then that (and maybe in that range to) are from a tuning/driving error. If that's the case and you put a "bulletproof" headgasket in there then next time you'll be building a motor because the headgasket will hold so the next link (read: bottom end) will give.

EDIT:I Noticed you said you were new to these cars. Do you have any type of scan tool or a way to monitor knock? If not you need to not push the car at all. If you do have a scantool or knock gauge were you picking up detonation when you blew it?
 
Never seen a blown headgasket push oil out the motor unless it blew into the vally. Other causes may be rings or a hole in a piston.

Pull the plugs. They have a story to tell. ;)
 
Be careful with the Cometics. They wont blow like a regular head gasket, and you lose that saftey net... Id rather replace head gaskets...instead of bent rods. Just a thought.
 
Yes, I'm new to this motor and no I have no scan tool, other than scanning codes on the service engine light. Sounds like it would be a good idea to get something. Knock gauge, nope. The engine is basically bone stock, with the exception of a cone type air filter. It's not a race car, nor will it become one. I love these cars in stock form and that's how I want to keep it, if possible.

After reading all of your posts, I have cancelled the order for the Cometic head gaskets and will opt for OEM instead. That seems to be the right call at this point. So, with that, which OEM type gasket should I get? I'm leery of the Fel-pro gaskets because I blew one of those on my 1979 turbo regal. Should I just get what NAPA or other chain store has?

Also, since both breathers are soaking wet with oil, I suspect that I blew out both head gaskets, which would really suck.

I'll pull the plugs. I just installed them 2 days ago so I presume they will look pretty good yet, unless something catastrophic happened. The plugs that I pulled were obviously in the engine for quite some time and looked mostly 'normal-ish'. Looks like the motor had been running a little lean at some point.

Other than this, I really like the car a lot.

Thanks all. I'll keep you updated as to my progress. More Head Gasket suggestions are welcomed.

Best,

Eric
 
Just do a compression test. Even if you only blew one cylinder into the lifter valley it would pressurize the entire crank case. Good call on not going with the cometics. As for scan tools see if you can pick up a scanmaster. If you can only have one scan tool they're great because you can use them all the time and they're simple to install/operate. As for head gaskets I would go with a felpro 9441. I've used a few and never had problems. Other than that probably go with an OEM type. One other recommendation is that if you're going to do both, (and I would not if you don't need to. If you only blew one then inspect the other to see if it's pushing out at all. If it is, replace it. If you think it's good then leave it) then upgrade to ARP bolts. You'd already have to spend money on bolts since the TTY style are not reusable so it wouldn't be a big price difference and it would give you a little upgrade in clamping force. Plus they're reusable. HTH. james
 
Thanks James. I did keep the order in place for the ARP bolts so I'm good there, thankfully. :) It's good to know that the ARP bolts are re-useable.

You're right about the compression test. That will tell me a lot, AND I'll get a chance to look at the plugs at the same time. I have not torn anything apart yet. The head gasket that is for sure blown is on the drivers side - which is actually kind of nice since there is a lot more room to work over on that side. I'm going to tear it down tonight (weather permitting) and see what it all looks like. Should be interesting.

I'll look for the Fel-pro gasket set.

Before I start tearing this thing apart, are there any gotcha's I should know about during disassembly? I want to unbolt the least amount of stuff as possible. Can I pull the head without >removing< the exhaust header? I know I have to unbolt the header, but does it have to be physically removed in order to get the head on/off?

Thanks all for your kind and well thought advice. You guys all ROCK!

Best,

Eric McCann
 
I had this same thing happen to me last year(my #3 cylinder blew out the fire ring into the valley, same symptoms as you are talking about). I was told to go with the OEM gaskets, I pay very close attention to knock, you have to get at least a Scanmaster to monitor knock and O2 count. OEM gaskets can take a lot of boost if the car is not detonating.
 
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