It's been 20,000 miles. Time for new headgaskets...

kenshi

Registered User
Man, I can't believe this. I just changed the headgaskets 20,000 miles ago and what does my car start doing? Why, overheating and blowing steam out of the exhaust, of course. I just about wanted to cry when I saw that. I think it was originally running hot because of the radiator but the headgaskets took all they could. My bike is my only other running vehicle right now, which is what I usually take anyway, but I have to have the car to go do my laundry and buy groceries. I tell you, it's a family trait to have bad luck with cars.

I'm trying to look at it from a positive point of view though. I've been wanting ported heads and roller rockers for a while now. It looks like now I have a good enough excuse to get them. Anybody have a good deal on some ported heads? Anybody feel like coming up and helping a brother out? I hope to have 325 to 350 bhp with heads, rockers, underdrive pulleys, and the two mods I already have. Does that sound about right? I certainly dread all the work I'm going to have to put into it though, especially in the middle of summer. Oh, I'm going to get Arp studs too so hopefully this won't happen again. I thought I'd post all this here and see if you guys had any suggestions.
 
The ARP Head studs for sure. If your interested in getting a tune, I would consider an injector upgrade instead of the roller rockers. I debated about them too, but decided against - they didn't seem like they were really worth the money.

What mods do you have done now? Depending on what mods you already have done, or do while changing HG's, it will be difficult to see 325-350, unless your talking crank HP. Then it might be possible?

I dyno'ed at the end of April on a very fresh motor making 266 RWHP. Here's a brief list of my engine mod:
Intake, 76mm MAF, 70mm TB, home ported 94 blower, 5% OD pulley, 5% OD JS pulley, UD's, double IC, 50# injectors, mild cam, mild port job on heads, stock valves, block bored .020., and slight port job on exhaust manifolds.

I'm pretty sure I'm making more HP now, but not sure how much more. Good luck with it - and like you said - it's a great excuse to do a few mods while your in there :D

-Melon
 
What other symptoms of a blown HG do you have? Loosing coolant? mixing with oil? Low compression on a cylinder? Just wondering what symptoms other than steam and overheating you have.
 
I am losing coolant yes. I assumed it was the headgaskets since it's blowing out the exhaust. I think the only other thing it could possibly be would be the intake manifold gaskets, but I don't think those just go all of a sudden. Last time I checked, a few weeks ago, there was no coolant in the oil, but that's before I noticed steam coming out of the exhaust. The gasket could be blown between a water jacket and a cylinder though, so that it doesn't get in the oil anyway.

My current mods are an ESM ported supercharger and a partial exhaust system (replaced cats with downtubes and got a decent resonator). I estimate my power (at the crank) to be around 260. It's not based on any hard evidence, but the 94's got 20 hp with a better blower and a larger pulley. I figured 50 sounds about right for a much better blower with the 89-93 pulley and a freer (more free) exhaust. I like the roller rockers not only for the extra power but also I'll get slightly better gas mileage and the engine will have slightly less strain on it. Plus I can go with a higher ratio and it'll be like having a cam when I don't. I'm considering getting a cam too though. How much better would a cam be than just getting higher ratio rockers?

I'm not trying to build a stupid-fast car. I have the sportbike for when I want to go stupid fast. I just want to put some more joy in my ride without killing reliability. (Really, I can't imagine this car getting any less reliable, but I've almost replaced everything, so I hope that'll change soon.) I prefer engine mods to blower mods too, because I figure they're better for reliability since they lower the boost instead of raise it. Plus I can just start out with the major mods and if I'm not satisfied, I can go to the bolt-ons later. (I've heard many people say they did it the other way, and wish they hadn't.)

I forgot to mention that I'll probably need injectors and a maf after these mods to keep from pegging them out, but I don't know anyone in the area that does dynotuning. This is really going to be expensive the more I think about it. I'm diving into the deep end head first.
 
Roller rockers are not worth the money spent on them. I've got a set on my SC and you really don't see any benefit unless you are going to consistantly go to 6000+ rpm.

Take a look at my member's page. I installed heads and picked up an estimated 20 rwhp and 18 rwtq. That's without a cam. By changing the ratio on the rockers, you're not going to see that much of a gain. In fact, it's been dyno tested going from the stock rocker arms to 1.8 RR and there was absolutely 0 rwhp gain. With all my mods I'm sitting at about 265 rwhp. That's right about where you want to be of 325-350 bhp (I'm at 331 bhp figuring 20% drivetrain loss for an auto...which mine is). And it's not too far off for a 5-speed.

It might be tough to reach that 350 bhp that you want, but it's possible. You will definately need a tune, regardless of whether you want it or not. Otherwise, you'll probably end up replacing the HG again...
 
ARP studs were mentioned-do you have a part # on these? Looks like I lost the HG lottery on the highway this morning on an 89 I just bought last night.
Crapped out radiator cap doesn't keep the coolant in very well.

Nick
 
Use the Chevy 2.8L studs - they are cheaper than the Super Coupe ones and are the same thing. ARP-233-4003 is the part number. Summit lists two for the Chevy 2.8L, but I don't think the other one is the one I used. Perhaps someone can verify this? I don't have any paperwork handy to check the P/N when I ordered.

-Melon
 
007_SuperCoupe said:
Roller rockers are not worth the money spent on them. I've got a set on my SC and you really don't see any benefit unless you are going to consistantly go to 6000+ rpm.

Alright. I guess I'll forego the rockers and get a cam instead. I always thought roller rockers were good for 10 hp at least, but if not, I don't want to waste the money.

Take a look at my member's page. I installed heads and picked up an estimated 20 rwhp and 18 rwtq. That's without a cam.

Not bad. I'm quite curious how much a cam would change those numbers. I figured with all those mods you have, you'd have gained more than you have. Maybe my expectations were a bit high.

walter89 said:
did you happen to reuse the orignal headbolts that were on the engine when you redid the headgaskets?

Negative. I bought new ones from Autozone. This time, I'll buy the good ones.
 
kenshi said:
Not bad. I'm quite curious how much a cam would change those numbers. I figured with all those mods you have, you'd have gained more than you have. Maybe my expectations were a bit high.

Yes, I'm limited right now by my cam and supercharger. I'm only getting about 13.8 lbs of boost (peak) and the stock cam just isn't taking advantage of the heads I have on the car. I'm in the process of a larger project that will bump my numbers up even more than a cam alone would do at this point. But you are correct in simply taking it at face value...it seems the mods would suggest more power...but I haven't got that bump stick in there yet to take full advantage of the rest of the stuff... :) I think that with a cam I would have seen a 60+ rwhp gain. My limiting factor would still be the supercharger...I've got to make 17-18 lbs of boost to get the power where I want it. That'll happen soon enough though...

If you are interested in heads, send me a PM, I can fill you in on some heads that are incredible...and hopefully they'll be hitting the market soon...otherwise, it's just ones'es and twos'es...
 
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