DattoChinook Posted June 2, 2013 Report Share Posted June 2, 2013 This thing has had a small exhaust leak (I thinks on the manifiold)... Any advice on pinpointing it and fixing it? Thanks in advance! Quote Link to comment
MicroMachinery Posted June 2, 2013 Report Share Posted June 2, 2013 If it's coming from the manifold where it attaches to the head, just replace the gasket. Same for if it's where the ex. manifold attaches to the downpipe. Quote Link to comment
DattoChinook Posted June 2, 2013 Author Report Share Posted June 2, 2013 If it's coming from the manifold where it attaches to the head, just replace the gasket. Same for if it's where the ex. manifold attaches to the downpipe. Thats what I was thinkin but I wanted to make sure... It has some other things going into the manifold ( Is it because it is an emissions engine?) and I was wondering if the leak might be coming from somewhere else other than right where the manifold meets the head? Quote Link to comment
DattoChinook Posted June 2, 2013 Author Report Share Posted June 2, 2013 I have replaced both sides of the manifold gaskets on a 4,3 gm v6 in the past. I just unbolted them and had play to slip in the new the gaskets and then rebolt them with torque wrench to specs... Is this pretty much the same process to a l20? I am the not the smartest engine guy, but can usually figure stuff out with some help from forum help/books. I want to figure this out on my own rather than ask my mechanic buddy for help who always wants to charge me some for hIs help. Quote Link to comment
laotsu Posted June 2, 2013 Report Share Posted June 2, 2013 L heads have studs that protrude you need the to pull the exhaust and intake to replace the gasket. 1 Quote Link to comment
izzo Posted June 2, 2013 Report Share Posted June 2, 2013 plus with it being a late year, the intake/exhaust are probably bolted together anyways.... Those are a pain in the dick to get under the exhaust manifold to unbolt it from the head. 1 Quote Link to comment
DattoChinook Posted June 2, 2013 Author Report Share Posted June 2, 2013 plus with it being a late year, the intake/exhaust are probably bolted together anyways.... Those are a pain in the dick to get under the exhaust manifold to unbolt it from the head.\ Damn not what i wanted to hear but thanx! Quote Link to comment
MicroMachinery Posted June 2, 2013 Report Share Posted June 2, 2013 Before you pull anything apart, you may check to make sure none of the nuts/bolts are loose. I've found some leaks that were cured simply by retightening a couple bolts/nuts that had vibrated loose over time. Don't go too tight, though. You don't want to strip threads or break any studs. 1 Quote Link to comment
DattoChinook Posted June 2, 2013 Author Report Share Posted June 2, 2013 It has been leaking slightly since I bought it in February. The guy I bought it from was a VW mechanic by trade, and he knew a very good amount about fixing cars. He bought a used 5 speed tranny off CL for this and installed it, realized it needed a needed a rebuild and reinstalled the 4 speed that it has now and came with. The fact that he didnt fix the exhaust leak himself makes me think it is something hard to diagnose and fix and somrthing even he didnt want to deal with... But what do I know? Damn not what i wanted to hear but thanx! Quote Link to comment
DattoChinook Posted June 2, 2013 Author Report Share Posted June 2, 2013 Before you pull anything apart, you may check to make sure none of the nuts/bolts are loose. I've found some leaks that were cured simply by retightening a couple bolts/nuts that had vibrated loose over time. Don't go too tight, though. You don't want to strip threads or break any studs. Sounds like I should find out the torque specs and give that a try first... Quote Link to comment
laotsu Posted June 2, 2013 Report Share Posted June 2, 2013 Nine to twelve pounds on my 210 head 1 Quote Link to comment
crackerjack69 Posted June 2, 2013 Report Share Posted June 2, 2013 Whatever J, come over and let's de-smog the mofo. Yeah, gonna be a bitch pulling the married intake/exhaust, but can be done. Bring over some beerz and gaskets for both manifolds, we can sort it out. I still say de-smog though, eliminates a lot of potential leaks, makes the motor way easier to work on for future repairs. But if you're pullin the exhaust, your pullin the intake on this one buddy. I'll help you for free no matter which way you decide to go. "Cho ass over here and let's fix it yo! Quote Link to comment
DattoChinook Posted June 2, 2013 Author Report Share Posted June 2, 2013 This thing has had a small exhaust leak (I thinks on the manifiold)... Any advice on pinpointing it and fixing it? Thanks in advance! I think this engine would sound so beautiful WITHOUT this leak!!!!! Quote Link to comment
laotsu Posted June 2, 2013 Report Share Posted June 2, 2013 You could buy farmers header... Quote Link to comment
crackerjack69 Posted June 2, 2013 Report Share Posted June 2, 2013 He don ned no farkin heder mang, needs to desmog that shit and git legit. 1 Quote Link to comment
DattoChinook Posted June 2, 2013 Author Report Share Posted June 2, 2013 He don ned no farkin heder mang, needs to desmog that shit and git legit. I down!! Quote Link to comment
DattoChinook Posted June 2, 2013 Author Report Share Posted June 2, 2013 Whatever J, come over and let's de-smog the mofo. Yeah, gonna be a bitch pulling the married intake/exhaust, but can be done. Bring over some beerz and gaskets for both manifolds, we can sort it out. I still say de-smog though, eliminates a lot of potential leaks, makes the motor way easier to work on for future repairs. But if you're pullin the exhaust, your pullin the intake on this one buddy. I'll help you for free no matter which way you decide to go. "Cho ass over here and let's fix it yo! I got beerz, a u joint for ya goon and and gaskets and tools and a few bux I could throw ya if you want to help me out buddy. It would be so appreciated! 1 Quote Link to comment
DattoChinook Posted June 2, 2013 Author Report Share Posted June 2, 2013 I got beerz, a u joint for ya goon and and gaskets and tools if you want to help me out buddy. It would be so appreciated! I gotts to pass deq in November so need to be able to get by that if I desmog though.... Quote Link to comment
DattoChinook Posted June 2, 2013 Author Report Share Posted June 2, 2013 I got beerz, a u joint for ya goon and and gaskets and tools and a few bux I could throw ya if you want to help me out buddy. It would be so appreciated! ill try not to get so drunk and STUPID at your house like last time hahaha! But it was cool to be able to pass out shit faced drunk all comfortable in the full size bed in the back of the Datsun!!! love sleepin drunk in my Datsun! 1 Quote Link to comment
datzenmike Posted June 2, 2013 Report Share Posted June 2, 2013 The '78 has a separate intake and exhaust. It's the '75-'77 that has the co-joined intake/exhaust that are bolted together. You could start a cold motor and quickly feel around where the down pipe to the muffler bolts to the manifold. The pipes will be cold enough to touch with your hands. You may be able to feel the exhaust puffing out. It you find it there, it's likely the thin down pipe has rotted away and needs replacing. A muffler shop is equipped for doing this and can bend you up a new pipe. If you don't find it there, wait and try again another time and feel up on and around the exhaust manifold. Possibly it's cracked in which case you'll have to find one from someone with a spare or from a wrecking yard. 1 Quote Link to comment
DanielC Posted June 2, 2013 Report Share Posted June 2, 2013 you can take a hose, hold one end up to your ear, and hold the other end to close to where you think the leak is, and pinpoint it. 1 Quote Link to comment
MikeRL411 Posted June 2, 2013 Report Share Posted June 2, 2013 And if you smoke, exhale around the exhaust assembly. Quote Link to comment
Guest_kamakazi620 Posted June 2, 2013 Report Share Posted June 2, 2013 Use a spray bottle with water in it spray around potential leak areas if the spray is disrupted there's your leak... 1 Quote Link to comment
darrel Posted June 2, 2013 Report Share Posted June 2, 2013 If the smog stuff is on it and hasn't been molested, keep it on. It will be much better in the long run to maintain what is there then it will be to replace it all when it's not there. There is a how to about rebuilding the stock carb. I was glad all the smog stuff was still in my 620 when I bought it, it passes smog with flying colors and since it's not a hot rod, I don't care how fast or slow I go. I would much rather trouble shoot a car/truck that hasn't been molested than one that has. Quote Link to comment
crackerjack69 Posted June 2, 2013 Report Share Posted June 2, 2013 De-smogging a 620 makes it far easier to work on, and eliminates tons of failure points. Quote Link to comment
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