78 4BBL 3.8 turbo charged 6

[turboLUVtruck]

I have a carburated/turbo 78 3.8L V6. I am very new to turbo's and had to remove the whole assembly to remove the intake and the heads. It had been sitting for years and leaked(or just condensated) in the cylinders and would not even turn. I am wondering, if I take a picture of the turbo assembly can someone help me identify the different parts. i am sure i'll have to replace some parts??!! I've been reading up on it and have learned a lot but need some help. Any help would be greatly appreciated. Maybe I'll just post some pics and see if someone can label the parts??!!

 

[slow305]

I used to own a 78 and had to do a head gasket swap. It was not funnest of my ventures. :frown: Try out this website:http://home.flash.net/~rjgeorge/ It helped me out a lot with identifying pieces and engine specific parts. If you can't find what your looking for, send me the pics and I'll see if I can help you out.

utaker7734@hotmail.com

 

[turboLUVtruck]

long winded response but i need a lot of help!!!

Thanks for the response. I've been to the site sent me, I actually found it last night and did a lot of reading on the turbo/carb/intake. I found some good stuff like vacuum line routing, intake etc... The problem I have is that the persont that owned the truck/engine before me had a lot of things capped off, removed or just not plugged in. There is no EGR anything on it, the waste gate hose wasnt plugged into anything, there was a clear tube that was plugged into something next to the compressor mount(it broke when I took unbolted it while removing the intake). It went up through the firewall into the cab of the truck(maybe for a boost gauge). There are some other things/hoses etc... that I'm not sure what they are for or where they plug into, or where they should be routed to. Some of the stuff thats not there I'm not sure if I even need(listed below). Some of it I can figure out but I would really appreciate your/anyones help. I work nights so I'll try and take some pictures in the morning and send them to you probably in bit map format so I can point to stuff and label stuff. I do plan to buy a Chilton or Haynes manual but I have found in the past that they are sometime not so usefull!?

Thanks again for any help you can give. :biggrin:

AIR Check valve (dont think it has one)
EGR manifold and valve (doesnt have one)
PCV valve(doesnt have one)
PEVR (power enrichment valve regulator)(doesnt have one)
Knock sensor (accelerometer) (doesnt have one)
Plenum coolant feed port
Plenum coolant return port
Thermal vacuum switch (dont think it has one)

 

[slow305]

Is sounds like whoever owned that engine before you really screwed things up. The coolant feed port can just be blocked or capped off (or possibly ice water ran though it?). You don't really NEED the knock sensor as long as you run 91+ octane at stock boost levels. By the way, is the "computer," I believe it's called a VSCS( ) still with the car? It should have wires running from the non-existant knock sensor to it and also from the distributor into it. If this piece is missing the knock sensor is useless anyway. Of course the PCV is important and will let dirt and grime fall into the intake manifold if it is missing. It's located on top of the manifold, kind of underneath the plenum. The PEVR is important so that detonation does not occur at higher RPM's or under acceleration. The EGR can just be blocked off by welding. What condition is your carb in? Is it the stock Q-jet? Keep writing with details. I have to work today, but I'll check on those pics as soon as I get off.

By the way, I used to own an older Chilton's, and it had most information in it about the older carburated turbo cars, but when I bought one recently, they seem to have removed all knowledge of such occurances. Good luck!

 

[turboLUVtruck]

long winded again.so many questions!

Yes, theres a lot of things screwey in this truck, including some of the wiring.So, I can just cap off all of the plenum coolant lines?That would mean cap'em at the intake manifold and at the carb base inlet and outlet right?I'll do without knock sensor.No it doesn't have the computer!Found the PCV valve port, there is just a hose running from the grommet to the connection at the carb.I'll get a PCV valve and install it. Found the PEVR port in the manifold(it's plugged).I cant find the PEVR at my local Checker auto store. Any suggestions where to get one?Or is it called something else?Also, by looking at the vacuum line drawings, if I install the PEVR w/o EGR where do I put the other hose?There are 2 that should come out of it, 1 from the carb into the valve, the other out through several other things(egr, check valve, thermac etc...)I dont have any of that stuff.I think I figured out where the wastegate hose goes. Looks like to the back of the carb from looking at the drawings at the before black site.The carb looks to be Ok(just visual/mechanically).It says Q-Jet ET on the side. How do I tell if it's stock or not?I found a casting number on the intake manifold that apparently means that it's an '80 aluminum intake. Yet, when I go to checker the only intake man. gasket that matches is from a '78. It has square intake/exhaust ports???!?! The one for the '80 has round ports?! I have so many more things to tell/show/ask you. I really need to take pics but the wife went out of town and took the digital cam with her. I'll borrow one from work and take pics tomorrow morning. I appreciate all your feedback. It must be difficult trying to answer/put up with so many newbie questions!? :redface: But I really appreciate it. I really want to get as many things right as I can and I appreciate the help!!! I'll send pics ASAP so some of these questions might be clearer. Going to bed now. Worked 13hrs, plus up at home now for 3more and I have to be in early. my email is jm_jesch@yahoo.com

 

[usetaboost]

THe only thing I can tell you is go to b4black site. There is great information on this site. I wish I would have not been so scared of my sport coupe when I had it I would have done more than just straightpipe and drop in k&n filter. THese motors are fun for daily driver's just make sure you got a good fuelpump and have the carb tuned correctly. Be patient. THe first time you hear that turbo spool will be great. It was when I got mine fixed.

 

[slow305]

Hey, it's all good man. I just love talking about these older, crappier engines because their so funny. Anyway, your best bet would be to try to find someone on the forum or maybe e-bay that had an intake manifold for sale and buy the whole thing. If that doesn't work, you might be able to get away with just plugging everything up and getting your carb tuned right.

The easiest way to tell the 78-79 intake maifolds from the 80-83 intakes is the knock sensor location. In 78, it was located right in the front (by the water pump) directly in the center. In 80, it was relocated to the block by the driver side exhaust manifold. I'm unclear about the exact location because I owned a 78. But the absence of the knock sensor provision should be a dead giveaway.

The 80 and above are superior quality because of the flow design and their aluminum construction. I believe the wastgate is suppose to hook up the the front part of the turbo where the 3 bolt flange meets the intake. There should be a nipple there for hook up.

The Q-jet carburator is engine specific to turbo buicks and T/A's. It has a special vacum secondary tuned just so it comes on when boost does. My old regal had a Holley someone had put on it sometime in it's life. The problem with that was the mechanical secondaries would come on as soon as I punched the throttle, so it would dump too much fuel and would bog down. It was bad at crusing speed, but REALLY bad from a stop. It would almost die if I floored it. The thing I suggest doing, which I never did, is to buy a air/fuel ratio gauge and O2 bung and sensor to get it in the ballpark. Or maybe EGT sensor. It's going to be tough to get it to run consistantly with the power enrichment valve missing. Mine ran much better on warm day's (around 60-80 degrees), with high barometric pressure (sunny also), but in Texas, those days are hard to come by.

Anyway, after that ramble, I say get it running, try to trouble-shoot from there, and maybe convert you carb into a throttle body and install injectors in the stock manifold for sneaky-ness. Just kidding

 

[turboLUVtruck]

thanks

usetaboost, thanks for the input. The before black site is where I've been getting just about all of my information so far. It's a great site. The only problem I'm having is that there really aren't any pictures of exactly what I have. What I have is an engine that has a whole bunch of stuff missing from the intake, things plugged on the carb etc... Plus it's being mated with a 1975 Chevy LUV truck. So not everything is going to match. I just have to try and figure out the best way deal with what I have. What to reomove/add and what to just deal with. I was hoping It'd just turn over, I'd be able to tune the carb play with the wastegate(boost), add a few higher tech parts etc... After the engine repairs, I need to replace the rear end(still stock), brakes etc... Should be a long, but hopefully fun learning process! Keep checking back for me, maybe I'll have some more questions you could help me with. Do you know where I can get a PEVER valve?!?!? This site ROCKS! I cant believe I'm getting so many responses. I didnt expect anything!

Later

 

[turboLUVtruck]

turbo pics

slow305, can i still send you some pics of my turbo/carb/intake etc... to see if you can help with some stuff? i.e where wastegate goes, where plenum coolant ports are/should be capped, where PEVR hoses go and a few more? Do you know where I can get PEVR?

I'll probably just keep the '80 intake and do what I can to get it running and like you said tune it from there. I just want to do/get as many of things that you all think I really need to make it run as best as possible! Which is why you guys are great.

I'll look back later for a response. I guess maybe I'll just send pics with a few questions!

Later

 

[slow305]

Yeah, go ahead and send the pics to my email account.

 

[usetaboost]

Well all I can tell you to do about vacuum hoses and valves and all that crap is good luck. The best thing to do would be to try to find pics of cars that are for sale with the same setup. Usually if it's a clean vehicle they will have nice detailed pics to go a long with it so you can see how things are supposed to be. Take into account there are a few check valves you may need also. Dig around either on b4blacks site or gnttype.org can't remember which one but has a very nice detailed hose diagram with all the check valves and that stupid valve in the intake where the hoses hook onto. THat thing always breaks. Oreilly's has them for the olds350 rocket, they might have them for the trs too. I epoxyed mine back together!

 

[usetaboost]

pevr

I forgot I had a 79 (I think) 3.8 out there with the intake still on it. It has that vacuum hose valve still on it. FInd out if yours has 2 or 3 ports on it. Now thinking about it my 82 might still have the valve on it too. I don't plan on using this stuff so if you need a driver's side exaust manifold or valve covers or anything like that, let me know. I have two motors that are pretty much complete down to the flywheel. I am using the 82 for my 87 we4 for something to "get by" with. If you need anything just send me a pm. I'll let you have it dirt cheap because I don't want the stuff sitting around too long. GOod luck with your project. Should be fun when it gets done!