JoeinCA Posted November 28, 2009 Share Posted November 28, 2009 So, some of you may know that earlier this year my second hybridz came to life. Since day one it has been plagued with intake manifold sealing problems. I have an 88' 355 in it, so it has the silly 72 degree center bolts, which limits manifold selection quite a bit. I ended up modifying a beat up winters 302 aluminum manifold after my cheapo weiand fail. I got the thing running, drove it 476 miles, and then the intake gasket failed... again. So i replaced the gaskets, again, and drove the thing around for another week or so, and the gasket fails again, but repairs itself mysteriously in the same drive. Another couple weeks go by, and I find an errant spark plug wire (BAD alternator belt, BAD!). SO after fixing that, the engien is runnign great again, and honestly I'm tired of babying the darned thing.. I mean what is the point of putting thousands of hours into an engine swap, and never getting the full effect of the power? By full effect I mean occasionally shaming kids in thier souped up turbeaux subarus. SO... When i was done shaming said kids, I noticed that i had in fact blown out the intake gasket. again... I take the next exit and head back home, in the drive of shame mode, with a massive vacuum leak, high idle and lean pops and all. I decide to shut the ignition off to slow the engine, thereby pumping unburned fuel and air into the exhaust. The first little back fire was funny. The second backfire wasnt joking. I turned the ignition back on, and there was an EXPlOSION under the car, and it suddenly became very... vocal. I limped the car the last mile or so to my apartment, parked it, and then lost the keys for a week. (No I really lost my keys for a week, it sucked). A few days ago, after I shattered the window on the porsche 914 (by SHUTTING the door) Ive been borrowing from a friend... I looked at the exhaust on the Z to see how badly damaged things were. The exhaust tip now points slightly downwards, and the muffler went from oblong, to about as close to round as possible. I feel bad foor the people who were behind me when the thing went off. I probably owe them new sets of underwear. Pictures coming later.. of the muffler! jeez. I am so done with this engine. But i cant afford to pick up a new lsx and t56, because i'm poor, and people dont hire people who arent supposed to lift over 10 lbs and walk with a stick. I brought the TBI manifold down from northern cal, and the holley tb, and have been trying to decide whether i should buy a new carbed cast iron manifold from gm performance, or if i should buy a MegaSquirt and spend hundreds of hours tinkering with that. Or if i should just try again with gaskets from GM, and stop messing around with fel-pro and mr.gasket. JB weld would make a good gasket.. right? Maybe i should just weld a chain to the engine and pronounce it boat anchor. Unfortunately, all of my tools and able bodied friends live 500 miles away from San Diego, so even that option is lost. Oh well at least thanksgiving was good, and semi-ironic. Time to make turkey salad! Joe. Quote Link to comment Share on other sites More sharing options...
jc052685 Posted November 28, 2009 Share Posted November 28, 2009 In for the pics! Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 28, 2009 Share Posted November 28, 2009 rtv...copious amounts of rtv... Don't feel bad, the AIR pump on a 1980 Chevy Luv will pump enough air into the exhaust during a 4th to 3rd downshift at 55mph that the muffler will not only have an explosion, it will damn sure enough split the thing down the center wide open! And that was in 1982, not even two years old! Quote Link to comment Share on other sites More sharing options...
letitsnow Posted November 28, 2009 Share Posted November 28, 2009 You should NOT be having those problems! My trickflow 195's came with that bolt setup, nobody makes a good intake for it, like you said, so I slotted the holes. I've had no sealing issues to date, 4 years and countless hours of abuse. I have a feeling it's related to the gasket you're using. What size are the ports in your head? manifold? which gasket? have the heads been milled without the intake faces being corrected? Quote Link to comment Share on other sites More sharing options...
JoeinCA Posted November 28, 2009 Author Share Posted November 28, 2009 The heads were brand new, PN 10125377. GM TBI performance heads. The block was shaved, very slightly, I belive it was only one or two thousandths. (Its been so long since the rebuild, I dont even remember the cam specs any more.) I am using a winters 302 manifold, ( I know, hacking at historical peices.. yadda yadda) I have been using fel-pro gaskets for the 88' k2500, and i tried some double thickness mr.gasket ones that got me as far as Oceanside. I think I may go by the chevy dealer today and get some good composite gaskets. or the double thick composite gaskets. I'm just getting tired of messing with it, i have a bad back and it is really not fun at all to keep changing the gaskets. Joe Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 28, 2009 Share Posted November 28, 2009 have the heads been milled without the intake faces being corrected? Where have I heard that before.... Block decking of a 'coupla thou' will alter the pinch at the bottom of the valley, but if it's only 0.004" the gaskets should accomodate that. Usually you can do the pressure paper bolt down and see if everything is compressing properly and evenly. Any radical changes either calls for a thicker gasket, remachining, or lots of RTV and setup time. Quote Link to comment Share on other sites More sharing options...
JoeinCA Posted November 28, 2009 Author Share Posted November 28, 2009 Tony, Pressure paper bolt down test? Please continue to expound knowledge upon me, I am apparently suffering from an ever increasing lack of knowledge. The more I learn, the less I know. (3 years ago I was an automotive tech, and now i can get a manifold to seal!) Joe Quote Link to comment Share on other sites More sharing options...
m4xwellmurd3r Posted November 28, 2009 Share Posted November 28, 2009 Pressure paper changes color based on h ow much force is applied to it. I think what he means, is to bolt down the manifold without a gasket, but with pressure paper in between, to see if you're getting an even mating surface all around Quote Link to comment Share on other sites More sharing options...
280znoob Posted November 28, 2009 Share Posted November 28, 2009 rtv...copious amounts of rtv... quote] x2 gratuitous amounts of Rtv Quote Link to comment Share on other sites More sharing options...
MONGO510 Posted November 29, 2009 Share Posted November 29, 2009 I have never seen his "pressure Paper". Where can I find it? Mongo Quote Link to comment Share on other sites More sharing options...
JoeinCA Posted November 29, 2009 Author Share Posted November 29, 2009 Heres a couple pics. It's still on the car, because i cant afford to get it fixed this week. I'll cut it open when it gets removed... Because I like seeing how well I break things... Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 29, 2009 Share Posted November 29, 2009 Pressure paper changes color based on h ow much force is applied to it. I think what he means, is to bolt down the manifold without a gasket, but with pressure paper in between, to see if you're getting an even mating surface all around Bingo! I think it's still available from McMaster Carr---why yes it is! Commonly used in bolted flanges and machined metal to metal surfaces to check for stresses and warpage of the made-up-joint. http://www.mcmaster.com/#pressure-sensitive-film/=4phx3a They do have it in 0.020" 'low pressure' applications. I have stacked the thinner stuff before, but that gets tricky. Stick it on the there 0.020" and lightly tighten the bolts. Not crank em down, just lightly tighten so you see a little compression. It should be EVEN across the face. If not, you will see just where you have warpages leading to leaks, and more importantly how much gap you have at those points. Great for deciding if you are going to mill, double gasket, or slather RTV and "Bubbles It"... (Hint: This stuff works wonders to diagnose warped heads if you cut it to head gasket template size and bolt the thing down even lightly! Dramatically records warpages you may never think amount to anything!) Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 29, 2009 Share Posted November 29, 2009 The more I learn, the less I know. HUZZAH HUZZAH HUZZAH! A man worthy of inclusion into the ranks of Hybrid Z! That is the first step to REAL knowledge! Congratulations, there are some who refuse to see that, and they can be quite bothersome... Quote Link to comment Share on other sites More sharing options...
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