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CarburetorsCarb discussion and questions. Upgrading your Third Gen's carburetor, swapping TBI to carburetor, or TPI to carburetor? Need LG4 or H.O. info? Post it here.
So i fixed up a lot of the wiring and its working a lot better than it was before. Terminals were loose or non existent, wire was fixed to be the correct gauge, battery terminals were upgraded. The alternator is only a 63 amp so its not great but it works. Probably going to do an oil change because it still has break in fluid in it (havent driven it much). Im still having a problem with it staring after its been warmed up though. Idk if its to do with timing being off a little bit still, not enough power to the starter, starter isnt good enough or if the starter gets hot and doesnt function as well.
There's a lot to read here.
Care to recap on where you're at?
Did you get a timing light and a vacuum gauge?
Have you addressed:
Ignition timing
Vacuum levels
Carb adjustment?
So i have a timing light and vacuum gauge, just havent had the chance to use them with all the other stuff going on. It need an oil pressure and volt gauge so i got some of those to put in. I would like to get a kit with a piston stop and the degree wheel so i can check where TDC is then do my timing, and the carb hasnt been played with but i know it needs it at least a little bit, never tuned a carb and i dont have an air fuel sensor. and its just a super weak start, slow cranking but still cranking. My plan is to finish installing the oil pressure and volt gauges then to confirm my TDC, does anyone have any kits that they would lean towards to find it? I would rather not pull the engine and tear it apart to find it so i was hoping to use a degree wheel and piston stop. After that I want to get the timing sorted then the carb assuming nothing else pops up, but i wouldn't be surprised
Determining TDC is an absolute.
Once you get there, post your timing results. As much as you can. Base timing at various RPMs. Do you have a vacuum advance and do you have any details as to the curve?
The carb settings come next.
Question: Have you ever done a compression test?
Those are important elements in the tuning process.
The compression test will give you an idea of a few details of the engine spec. If the compression is miserably low, or differs by a large percentage from cylinder to cylinder, you could probably pull the plug on the tuning and consider an engine replacement. I think the expression is "flogging a dead horse".
As for the vacuum advance, that part of the timing as well as the initial and centrifugal curve are vital. My experience has shown me that timing has more value to engine performance than the compression ratio.
Of course, the engine has to be a good state of tune and reliable enough to test consistently which appears to be what you've been doing.
I'll be watching for results.
Maybe I can contribute too.
you need to focus on checking one system(timing) from start to finish,then check your carb.you jump around far too much and you never actually follow through with any one thing.buying a timing light and vacuum Gage is great but you need to learn how to use them in the proper manner and use what readings you get to correct your current issues.
the issues you have are not extremely difficult to deal with but you need to be disciplined and do a checklist and follow it to the letter collecting data as you go.
1)if your timing is too advanced it will either hard start or not start at all.
2)you need to establish tdc and then mark it on your harmonic balancer.
3)you need to set your timing with your vacuum advance disconnected.
a couple quick questions,do you still have an electric fuel pump and pickup in your fuel tank?when switching to carb from efi it might be an excellent idea to have a carb specific fuel pickup in your tank.do you have a vacuum advance distributor or the old efi distributor? this is very important.
you need to look at one system at a time(fuel---spark---exhaust) from start to finish to trouble shoot your current issues.
It's going.
From a 3rd gen standpoint, I'm in a holding pattern. Engine has developed a misfire. Tests are showing the shortblock might be going away but I'm going to have to dig into the ignition a little further. Maybe valve springs but I'm doubting that.
In the meantime, I've been sourcing parts for a stroker but there's more on my plate than the car these days.
That said, someone explain to me why I've just picked another 3rd gen roller? A rust free 82 Coupe. Now what...?
It's going.
From a 3rd gen standpoint, I'm in a holding pattern. Engine has developed a misfire. Tests are showing the shortblock might be going away but I'm going to have to dig into the ignition a little further. Maybe valve springs but I'm doubting that.
In the meantime, I've been sourcing parts for a stroker but there's more on my plate than the car these days.
That said, someone explain to me why I've just picked another 3rd gen roller? A rust free 82 Coupe. Now what...?
a turbo 6 would be cool especially in a stealthy/sleeper package,or maybe the venerable ls/t56 that runs like a new car and looks like a 36 yr old third gen(but overdone).something unique would definitely be cool,or a big cube turbo 4 ?something that people say,why didn't i think of that.another thing that would be tricky but fun and controversial would be a newish hemi or coyote build in a camaro after all look at all the ls powered fox bodies.
Last edited by 1986BANDIT; 06-24-2018 at 04:47 PM.
Reason: spelling
Thoughts going forward are a refresh on the 355 (.040" over !) and nitrous. That would be an interesting track/street car.
One chassis or the other will undoubtedly get an LS conversion. I have a 5.3 litre from one of my Tahoes ready and waiting.
It's only been a couple of days. Sometimes these things take a little time. Hell, I haven't been to the track now for two seasons so some of my racing threads have withered up and blown away. As my racing buddy would say, "It's always something!".
Hey guys, sorry haven't been able to touch the car, family grad parties and open houses. My brother needs some help tearing down an inline 6 jeep engine so im gonna dk that tommorow and maybe tuesday then ill be back at it
So we took apart the engine and we also had to take out the transfer case for my brothers truck and i might have to put that back in before working on my car because his truck is a daily driver. So i bought a dial indicator with a magnetic base so i could measure the top of the piston to find the top dead center. So i was wondering when i take the head off should i drain the oil and coolant or should i not even do it this way and just get a piston stop and degree wheel? Also i added a picture of the cylinder from the jeep engine for humor
So, ive started pulling the head off and right now, its not looking great. The rockers are starting to get eaten up, studs are coming out when i loosen the nuts on them, and quite a bit more. The head isn't off yet but its close. Im thinking of pulling the engine and doing a full tear down and rebuild. The oil smelled like it had gas in it too.
if you are finding serious issues like this its probably a good idea to pull it out and either rebuild it or find a GOOD,RUNNING 305/350 and that shouldn't be terribly hard
I would like to rebuild it but i dont know if i can because of lack of knowledge, expence and time. I mean i would love to be able to rebuild and i probably cant afford a decent new engine. I dont really know what to do. I mean all of the rockers seems to be being eaten away, a few worse than others, studs are literally just coming out with the nuts, one of the valves on the cylinder head that i pulled is white and looks like it has heat marks on it, i didnt get a chance to check the lifters but i hope they're ok, when i pulled the head there was a bunch of coolant in the cylinder but that might have been because it wasnt all drained, the oil smelled like gas and thats just what i can think of right now.
it seems like you have a "mystery" engine built by someone who would fail as a laborer in a pillow factory and it definitely was never assembled right from the beginning.
i dont know ? are these supposed to be self aligning rockers? are the pushrods loose(large hole in the head) ,the right length(very important)or small hole in the head to
"guide the rocker".it seems like the guy before you didn't understand zero lash plus half to 3/4turn on all rockers.you might want to look at the cam and lifter faces to see
if they have catastrophic wear(really bad and noticeable wear)definitely assess what is going on.you might also want to keep everything in the order you remove it
(it may be too late for that but its worth the effort if everything turns out to be o,k)
if the rockers were over-tightened and the cam not properly broken in it
could be a total mess inside that engine and its hard to tell without seeing it.
hopefully skinny z or others will chime in and give their guidance as well.
Last edited by 1986BANDIT; 07-29-2018 at 02:39 PM.
I'm thinking of pulling the engine and doing a full tear down...
That doesn't sound like a bad idea.
But at the very least, get the heads off.
Drain the oil and have close look for metal particles.
You can address quite a bit once you're at that point. If it's in decent shape mechanically, that is, the cylinders/piston tops look OK you may get away with some careful reassembly.
If the lifters look good and they still have a convex contact surface (easy to check), chances are the cam is good too.
The rest of reassembly isn't that complicated nor does it have to be expensive. Attention to detail is the key.
The damage to the rockers could be the result of poor valve train geometry. Mixed and mismatched components will get alignment out of whack and some measuring is required to get things back to where they should be. That could mean the valve guides have been wiped out. That easy (and cheap) to check too.
You've got to get it apart first.
If you have flat tappet lifters, they MUST be kept in order if there is any chance of reusing them.
Make a holder from a piece of 18" long 2x4 and a 1" spade wood drill bit. Mirror what the lifter valley looks like.
Last edited by NoEmissions84TA; 06-30-2018 at 08:26 PM.
The rocker studs will come out if you don’t loosen the Allen set screw in the middle of the poly locks. Are the rockers hitting the valve springs or is it galling at the pushrod end?
Hey guys. Sorry for going silent for a while. Went on vacation for a week then started working again so I haven't had much time to do anything with the car. I've been trying to make a list of things to buy since i pulled the head off. Right now I need head gaskets, header gaskets, intake manifold gaskets, rocker arms, possibly push rods (idk what rocker arms to get and how the ratios work), head studs/bolts, and possibly some other things but i cant remember or don't know right now. I was thinking about pulling the engine but I dont know if I will have time because my brothers truck needs a new cab (found basketball size holes in the floors and the cab corners are pretty much gone) and he needs all the help he can get so I think he is going to buy a new cab. Once again thanks to everyone for helping me out with this project, its been a pain because none of this really should have happened but I guess its what you get for buying a car you know nothing about for a few grand. If anyone has recommendations for the parts above let me know. Im thinking ARP bolts (dont know which set to buy though), comp cam rocker arms and push rods if i need them (also dont know which ones to get, i guess the scorpion ones that were on there were pretty beefy and for racing but those are expensive), and felpro gaskets. Thanks guys
BTW thats what the rocker arms look like on the bottom, Also there are all those weird wear marks on the valve springs, is that something I should be worried about?
I see a stock retainer, a valve that hasn't been spinning like it should, and ... TRASHED DESTROYED WASTED rocker arms. Looks like the studs musta been screw-in type with a hex, but the head casting boss hadn't been cut down to a consistent offset from the decks like they're supposed to be, that ends up usually about .375" or so below stock, so the hex sat way up high ALL UP INTO that schitt and ate the bottom of the rockers up. You can't "take 300 thou off" or whatever, doesn't work that way, gotta cut the random factory casting height down to some relatively specific height above the deck.
Sorry, I'm not going to wade all the way back through 3 pages of posts to get the details if there are any, but that's what this photo shows.
Your stock head bolts are fine. (assuming they're not trashed in some way or other... they're not inherently inadequate, or not re-useable, or one-time-use-only, or anything like that... I've built no telling how many 400, 500 HP SBCs over the years with used stock head bolts without EVEN ONE head-bolt-related failure) I sure as hell wouldn't buy $$$ARP$$$ to put into ,,, that. I'd go to the JY and tear down acoupla blown-up shrapnels before I'd waste that kind of $$$$$.
I think that once the rocker stud installation problems are solved, the rockers will be fine, for maybe 20k miles or so at least. Being aluminum they're destined for a very short life on the street, not going to run into the hundreds of thousands of miles regardless, but within reason, they should "work" "fine" for a little while anyway.Once you get the basic interference problem taken care of, then file off the burrs and all that, they'll be good as new, as long as you don't expect too much.
What cam is in this? What castings are the heads? Those 2 questions, plus an HONEST assessment of your goals for the ultimate outcome of this project, will tell you whether what you have is even internally compatible at all, or what. Or, whether there's some critical parts that need to go in the trash and start over; or whether you should work up what you have. You might be surprised at how quick working over stock heads to get them to "performance" standards costs these days, and at what point it becomes economically more sensible to throw em out and start over with new better something else.
Last edited by sofakingdom; 07-26-2018 at 07:16 PM.
Comp cam 280H and camel hump heads, casting number 37824641. And the studs have nothing on the top like an allen or torx to put them in, idk how tight they have to be or if they need thread locker put they are loose enough to be taken out by hand. I have no idea how to cut down the head or do that consistently. And im going to just get new rockers id rather not run the engine like that. Im not trying to build this car to be a drag car or crazy street machine. Yeah id like a little bit of performance but im not going to drop a few grand into aluminum or cnc ported heads and all that, I just want to be able to drive it at this point to be completely honest.
It would take a machine shop to cut the heads. They would cut the bosses off to some point, such that they are all the same distance above the deck, and of course perpendicular to the stud hole.
So if the studs don't have the hex, then the rockers are hitting the stud boss itself. Not good. Problem with just getting new rockers is, there's no guarantee that any other rockers wouldn't do the same thing. If they're hitting the heads, then there's some other problem of some sort, somewhere. I'm not at all sure that replacing them would actually solve anything. And I really don't think that the damage they've suffered so far, is serious or anything close to it, anyway.
With 461s you're going to have a real issue with accessories as I'm sure you already know. If it was me, I'd replace those, rather than the rockers. But that's just me.
The studs for the rockers should have the allen in them im saying the studs for the head dont, those are loose enought to be taken out by hand. The accessories arent a big deal, all im running is an alternator and power steering and i already have those set up. Not sure on the pushrods right now ill have to check when i get home. I havent looked closely at the retainers again i can look when i get home.
Push rods are between 7.75 and 7.8125, the rocker arm studs have allens in them not head studs though. Also added a better picture of the valve springs
Ok, so my brother works at a place that has cnc mills and everything and he said that he has tools that can machine down the surface. How far should it be machined down? Or should i get new heads? And i can get new retainers. I would have never noticed that they were bad
just google search "modifying sbc gen 1 heads for screw in studs" you will find all the info,or call an automotive machine shop and ask them some hypothetical questions.
it would be easier to get what you have working rather than spending a pile of money UN-necessarily in my mind.write down were you are at and try to fix one thing at a time
in an organized manner,dont jump all over or you will have a mess on your hands in no time and another "basket case project for sale" ask me how i know,lolol
Lol sounds good. I mean i dont mind buying new parts but yeah i would rather stay away from it if i can. I mean yeah i could reuse the rockers but they're pretty trashed. Ill probably need new pushrods if im machining that surface and gaskets and what not.
Lol sounds good. I mean i dont mind buying new parts but yeah i would rather stay away from it if i can. I mean yeah i could reuse the rockers but they're pretty trashed. Ill probably need new pushrods if im machining that surface and gaskets and what not.
Or should i get new heads? And i can get new retainers.
That is probably the best idea.
Maybe someone with a nostalgic side will take the 461's. You can probably find some used Vortecs cheap. I sold a fully modified set with upgraded springs (Comp 26918), screw-in studs w/ guide plates and enlarged pushrod holes for under 500 bucks so the deals are out there. Just ensure that they aren't cracked. Buying them used may leave something in the budget for the required intake manifold.
It's difficult to say from the pictures, but if the rockers bodies are the only thing damaged, they may be salvageable. Your brothers machine shop should be able to clean them up easily enough provided the roller tips, pushrod cups and fulcrum aren't mangled.
I might be able to go to some local junkyards too and pull some heads but idk if thats the best idea. I dont know much about this stuff so i dont want to get some garbage heads not knowing
The only good junkyard heads are 96-2000 350 Vortec heads and they require a different intake manifold. Although they will support 400hp in stock form and are the best iron heads chevy made stock.
Yeah, Ill just have to do some more research and see whats the best option. Im just hoping I wont have to blow my whole budget on new heads
Like I said all junkyard heads are worthless except vortec and if you get any junkyard heads you willneed to get them checked for cracks and have new springs retainers and keepers installed.
06-21-2018, 09:42 AM
