Recently finished a 4.0 head swap, trying to see if the thing will run. Don't quite have timing dialed in (didn't mark distributor) but it's to the point that the car will fire up if I give it enough gas. Problem is, it seems like as soon as it starts it wants to rev to high heck and I have to shut it down. The throttle linkage assembly isn't hooked up, so I'm just working off the carb. What could cause the car to rev high even without any throttle?
UPDATE: So I tore down the engine again, reassembled, checked and rechecked plug wiring, vacuum ports, etc. Only things not hooked up are: Throttle linkage/kickdown/whatever that other cable is that goes to the passenger side of the engine compartment. Shouldn't be an issue to get it running, right?
So, the issue this time is, I cranked for a while, gave it some gas, cranked, and got a decent sized detonation out of the carb. Stopped there, waiting for my battery to charge back up, but I'm unsure what this could be now. The reason I decided to swap the head (in addition to the power gain) is because I got a loud popping out of the carb with the 258 head, which was thought to be a stuck valve. But, with the 258 head, the engine would at least run.
Any ideas? I don't wanna hurt this engine by cranking and cranking when something could be wrong.
stuck on fast idle cam, major vac leak...
Major vacuum leak or the lack of a return spring on the throttle shaft/carb.
Find TDC and give it a 1/2" advance form there for the initial start. Make sure your plug wires are in order.
Might as well just do it right, how do you set initial timing if you're installing a new distributor (since it wouldn't have been marked)? Anyone got time to walk me through that process so that I know which point on the distributor represents the #1 cylinder?
Also remembered I didn't put my EGR valve on (or block it somehow). That'd be a major vacuum leak, right?
If you just plain have NO EGR valve OR block off plate??? Yeah, I'd call taht a major vac leak, not even sure it would run at all in that configuration...
Not sure how to block it off, I suppose putting the valve on and plugging it would work (maybe?) but I'm not sure how I'm going to plug the hole for the exhaust on the bottom of the intake. Any ideas?
I cemented a pipe thread plug into one. incorrect thread but close. it works.
Quote from: doc65 on March 28, 2012, 05:03:55 PM
Yeah, I'd call taht a major vac leak, not even sure it would run at all in that configuration...
Mine did, started and instantly revved up to about 2300 rpm.
Yeah, it'll definitely run, and like ammachine390 said, rev up pretty high instantly.
EGR valve is installed, capping off the nipple should be enough, right? Then blocking off the exhaust part of it should provide a complete seal, unless I'm missing something. And every vacuum port coming off the intake should be either used or capped, correct?
Capping the nipple shouldn't even be necessary, that nipple feeds a vacume diaphragm that opens the EGR, so no vac on nipple, no open EGR...
Still haven't figured it out. Manifold vac lines are capped, carb lines are capped (except to vac advance), EGR valve is installed, capped, and exhaust portion is blocked. PCV feeds to back of carb, carb feeds to booster. Car will start if I flood it with gas, and will run if I keep feeding it too much gas. Checked my spark plug wires, all are good, even tried moving them clockwise just in case. Turning the distributor seems to have no effect on how it sounds when cranking, haven't tried turning the dizzy with the car running because it takes way too much gas to keep it running and I figure there has to be a better way.
So close, yet so far away. :help:
Have your ICM tested or replaced.
It's been converted to HEI and the emissions equipment has been removed.
Any ideas? Swapping the plug wires resulted in a loud bang much unlike how it sounded when the car was able to start. So I'm assuming that's a non-issue and I'm wired up right. I checked TDC on #1 before installing. I'm really lost here. I've never even set timing on a car, let alone set it after yanking a dizzy without marking it.
I'm understanding it starts but won't stay running unless it's given throttle. If this is correct...and you've plugged all sources of vacuum leaks...I think the distributor rotor installed in the wrong position can be ruled out. I believe you said you did a 4.0 head conversion...did you change the can or timing chain at the same time? :eagle:
Well, it won't start unless I flood it with gas, then it'll fire up strongly and I need to continue flooding the heck out of it to keep it running. Basically I need to keep the RPMs up above a certain level and she'll run, but doesn't sound great (not sure if that's cus of an issue or because I've never heard a L6 with an open header). I did do a 4.0 head swap, but no, I did not swap the cam or timing chain. In my mind the fact that it will "sort of" run rules out the dizzy.. the firing order has to be correct in order to keep the engine going, right? The only vacuum leak I have that I didn't realize before just now is my 4x4 vac line isn't hooked up. I believe that just goes to the back of the intake manifold, right? There's a couple ports sticking up back there.
I feel like that small of a leak wouldn't affect it starting, but I'm obviously no expert. I actually tore the engine back down because my theory on the water jackets was incorrect, so I'll be pulling the head again and reassembling. My carb is leaking gas a little bit under where the electric choke is, so I may need to pick up a rebuild kit for it and just go through it.
While I'm typing, I've been meaning to ask about torquing down the head. I was reading to torque the bolts down to 110 ft lbs, and I believe that's around where tougeagle had them torqued when he regasketed the car the first time with me, but I could be wrong. Anyway, I've now split apart two 5/8 sockets and broken a nice Husky torque wrench going to these specs. Further research shows some people suggesting torque as low as 85 ft lbs. Silly thing to think about now, but I thought I'd ask so when it goes back together it's correct.
According to the AMC manual the correct torque if 85 ft/lbs. :eagle:
110ft./lbs. is for the 4.0L engine, you will want to torque yours to 85ft./lbs. I torqued mine to 85 on my 4.0L swap and is still holding very well after 7k miles. You will want to make sure your water jackets are JB welded good, but I am assuming you already did that. Sounds to me like your carburetor is gunked up and your float and needle are not properly moving. What kind of carburetor are you running? You might have to re-jet it if you had to mill down the cylinder head or the engine block any. Either way, your carburetor seems to be the major culprit. As far as timing, to start off, I would put #1 cylinder at TDC Compression, then index your distributor and drop it in so that the rotor is pointing just after the post on the cap for #1 wire and so that it points somewhere around 4 o'clock, that will give you a good starting point and allow you to adjust timing once it is running better.
Updated the OP.
I used the 4.0 gasket and slotted my manifold like you described.
Anyone? I'm really stumped here. Went out and tried it again, same thing. Doesn't even sound like it wants to run while cranking, then a big pop out of the carb.
Quote from: NoCoEagle on March 31, 2012, 04:41:11 PM
Well, it won't start unless I flood it with gas, then it'll fire up strongly and I need to continue flooding the heck out of it to keep it running. Basically I need to keep the RPMs up above a certain level and she'll run, but doesn't sound great (not sure if that's cus of an issue or because I've never heard a L6 with an open header). I did do a 4.0 head swap, but no, I did not swap the cam or timing chain. In my mind the fact that it will "sort of" run rules out the dizzy.. the firing order has to be correct in order to keep the engine going, right? The only vacuum leak I have that I didn't realize before just now is my 4x4 vac line isn't hooked up. I believe that just goes to the back of the intake manifold, right? There's a couple ports sticking up back there.
I feel like that small of a leak wouldn't affect it starting, but I'm obviously no expert. I actually tore the engine back down because my theory on the water jackets was incorrect, so I'll be pulling the head again and reassembling. My carb is leaking gas a little bit under where the electric choke is, so I may need to pick up a rebuild kit for it and just go through it.
While I'm typing, I've been meaning to ask about torquing down the head. I was reading to torque the bolts down to 110 ft lbs, and I believe that's around where tougeagle had them torqued when he regasketed the car the first time with me, but I could be wrong. Anyway, I've now split apart two 5/8 sockets and broken a nice Husky torque wrench going to these specs. Further research shows some people suggesting torque as low as 85 ft lbs. Silly thing to think about now, but I thought I'd ask so when it goes back together it's correct.
How certain are you there isnt a leak at the manifold
Fairly certain, I just installed the manifolds while the head was out of the car, proper torque sequence, look absolutely flush, good gasket, and can't see anything wrong using the carb cleaner test.
It needs to be running by May or I will be forced to scrap it, unless someone with a trailer wants to buy it. I could really use some expert help, I've done about all I know how to do.
Quote from: NoCoEagle on April 10, 2012, 02:02:53 PM
Anyone? I'm really stumped here. Went out and tried it again, same thing. Doesn't even sound like it wants to run while cranking, then a big pop out of the carb.
That sounds like timing now.
Have you put a timing light on it and confirmed spark is happening in the proper place?
Have you double checked your firing order?
I think I read that the computer is bypassed already, so that shouldn't be a concern...
I've checked plug wires, I set #1 to TDC when I dropped the dizzy in, I'll run out and check one more time where the rotor is facing at TDC and make sure everything lines up. Had this issue with my 68 Javelin and the new demon carb, ended up being a distributor issue, but I've looked and re-looked at this thing so many times now.
My stroker carb (for tink715 hence the color) looks like this.
(http://i216.photobucket.com/albums/cc55/mudkicker715/2012-04-10160824.jpg)
(http://i216.photobucket.com/albums/cc55/mudkicker715/2012-04-10160843.jpg)
i blue printed this to the gasket to be certain of no leaks. as i did with my other carbed stroker
Hope this can hel0
Should of said for the bottom side pic look at the stud for the intake. is yours similar?
Yes, mine isn't very pretty, but I did cut out a half circle from the intake to clear that stud. Sitting right on top just like yours, and the edge of the top of the intake (where the runners are) doesn't extend past the cylinder head surface.
Turns out I'm an idiot, and just got a nice reminder from 3 years ago or so. When working on the Javelin, I had installed a new Demon carb and distributor. Despite me checking over and over, and thinking my plug wires/distributor were right, I was 180 degrees out. Carb would backfire and light on fire when I tried to start the car. No fire on this carb, but same situation... and it turns out I'm 180 degrees out again. Not sure how I botched that when installing the dizzy with the engine at TDC, but whatever... hopefully this works. Will update soon.
It still won't start.. ha. What a tease. :banghead:
I have a rough idea of what I'm doing, at best. I'm 19 years old and teach myself by logging onto forums and seeing what other people are doing to fix things. I redid the wiring today, when #1 is at CTDC the rotor is pointing at the #1 plug terminal and I've wired it clockwise from there 153624. It stopped backfiring but won't start up, I wasn't able to try for too terribly long till my battery went and I had to charge it up.
I'd certainly be open to receiving help, although I'm pretty out of the way and the time issue makes it tough. I live in Drake up on Storm Mountain between Loveland and Estes Park. I know there's a few nesters down near CO Springs, not sure of any out this way.
Sorry you're having so much trouble. I wish I was in town, I would swing by.
Quote from: NoCoEagle on April 11, 2012, 02:38:38 AM
although I'm pretty out of the way and the time issue makes it tough. I live in Drake up on Storm Mountain between Loveland and Estes Park.
Man, that night I went to pick up that crank from you, I was not expecting that terrain on the way to your place. I was in company truck and thankfully it was 4wd with some aggressive tires, otherwise I would have gotten stuck in the snow when I took that wrong turn. ;D
I'm glad it was well equipped! I hope that crank was worth the trouble. Especially in the winter, that road surprises people!
The easiest way for me to get firing order right is 1-1, then going counter clockwise skiping every other terminal. 1 skip, 2 skip, 3. Then, one position counter clockwise from 1 is 4 (now going clockwise) 5, 6.
If you are TDC, give it a hefty advance and see if it starts.
Still no luck, unfortunately. I'm getting fuel, I have no idea what is incorrect.
Make sure the wires are going in the right direction! Also, can you do a compression test? If teh valves are too tight, compression will be down.