Thread: Engine driving me nuts!

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Hi everyone. I have a Chevy van/sleeper project that is driving me absolutely nuts. I have hit that issue that I hope someone had solved.
I have an 86 Chevy van G20, conversion. I have gutted the interior, modified the suspension, front and rear. I had a stock engine that I modified with a .196/.204 cam, It has been bored .030 over, planed, the heads were replaced with 64cc., emissions heads. I have an Edelbrock performer manifold, intake and exhaust port matched with an Edelbrock 1400 EGR carb. All the emissions have been restored on the vehicle.
At about 8000 miles, the engine started missing. I changed the plugs, wires, module. I replaced the distributor. I have the engine timed at factory 4bdc. I have retuned the carburator. The plugs came out on the right facing forward, back, black, three back, white, two back white, one, black.
It has pronounced hesitation from a start and I had to set the idle to 750 to miss the hesitation. Oil pressure is 68lbs on start up, with 48lbs at normal running temperature, 28lbs at idle at 750, 22lbs at 550.
On the Edlebrock I am 1 1/2 turns out from closed and tweaking 1/8th turn at a time.
It has dual pipes with crossover. It sounds smooth from the outside, and powerful. Inside you can feel a shudder, and it feels like it has less power. Fuel mileage is about 18 around town. I do not know highway.
Hoses are new and tight, no vaccum leaks. I am lost. Can anybody help?

Originally posted by docone31
Hi everyone. I have a Chevy van/sleeper project that is driving me absolutely nuts. I have hit that issue that I hope someone had solved.
I have an 86 Chevy van G20, conversion. I have gutted the interior, modified the suspension, front and rear. I had a stock engine that I modified with a .196/.204 cam, It has been bored .030 over, planed, the heads were replaced with 64cc., emissions heads. I have an Edelbrock performer manifold, intake and exhaust port matched with an Edelbrock 1400 EGR carb. All the emissions have been restored on the vehicle.
At about 8000 miles, the engine started missing. I changed the plugs, wires, module. I replaced the distributor. I have the engine timed at factory 4bdc. I have retuned the carburator. The plugs came out on the right facing forward, back, black, three back, white, two back white, one, black.
It has pronounced hesitation from a start and I had to set the idle to 750 to miss the hesitation. Oil pressure is 68lbs on start up, with 48lbs at normal running temperature, 28lbs at idle at 750, 22lbs at 550.
On the Edlebrock I am 1 1/2 turns out from closed and tweaking 1/8th turn at a time.
It has dual pipes with crossover. It sounds smooth from the outside, and powerful. Inside you can feel a shudder, and it feels like it has less power. Fuel mileage is about 18 around town. I do not know highway.
Hoses are new and tight, no vaccum leaks. I am lost. Can anybody help?

Don't sound like to me you have a miss. 18 mpg around town, idling at 750, It sounds smooth from the outside, and powerful. you need to put a vac gauge on the motor and get a reading. Sounds like to me you have a vibration, not a miss. let me know on the vac.

Check your EGR valve, and if it's a automatic the hose to and the vacuum modulator its self.

I am also wondering if one of the emissions controls is askew. When I got the van it had an LT 1 full race engine. It was miserable. The van is a grocery getter and shop van and general enjoy the drive machine. Changing the distributor solved the no spark on occasion issue, at least for now. It does go through approximately 1/2qt of oil every 3 thousand miles. Oil colour is light tan at 3 thousand.
I might check the carb mounting bolts, manifold bolts for leakage. I will recheck the hoses. When we first got the van, all the emissions were unbolted and gone. I had to replace everything. We have no emissions test in this state but I still feel it is the right thing to do. An awful lot of the devices I had to get from a boneyard. The engine is not really broken in yet. At 500 miles we left Los Angeles and came back to Floriduh. We drove tender and the engine did not consume more than 1/2 qt. of oil. That cam has amazing low end power and we never have had it over 2500 rpm. We also rebuilt the rear and went from 3.23 to 2.73. I figuired with gas prices what it is going to be we could benefit from being tall.

I have replaced a lot of parts in the transmission. The vaccum modulator. I never thought of looking at the tranny. The egr valve. It did happen suddenly once we got back to Floriduh. An hose could have slipped there.
Thanks, gives me a place to look. When I adjust the carb idle mixture screw it seems to make no difference. The idle is a little high to compensate for the hesitation. I might back down on the idle once I find the source of the shudder. I know so little about emissions. Thanks

That is around town. I also had the crank stroked. The engine that I had rebuilt had had 305 , 54cc heads put on it. I had heard the 305 heads increased the compression. It doesn't make sense someone would do that to a van. We went back to 64cc heads.
I am also wondering if roller lifters would help with fuel economy. If not, if it ain't broke leave it alone.
I also cannot get it to ping, even with low octane fuel. Could that be connected to the shudder.
I know how difficult it is to diagnose from a distance, especially on a forum. I appreciate the feedback. When I have light, I am going to check the vaccum line to the modulator, the EGR lines, and I am going to look for a leak in the advance vaccum line.
Man made it, man can fix it. I will persevere!

Just a progress report. Today, being off from our shop, I got into the engine. Armed with information from the forum I checked the EGR, vaccum leaks around the hose ends, loose things in general.
Then I went to the timing. I set the timing to 4bdc as per specs., however I did cam the engine. When the cam was installed, it was installed at 0 degrees. I could have gone 3 degrees or five degrees either way but I chose 0 degrees.
I loosened the distributor and went by ear. I always used to tune by ear, timing, and carburator balance. The first time I timed the engine I did it by a light. This time I went by ear. I am probably up to 6 degrees bdc and it purrs. There is just a tad of hesitation coming off a light with a light pedal, but the shuddering feel is gone as is the major hesitation. Once I had the timing dialed in by ear, the Edelbrock became tuneable.
According to Edelbrock, the start point is three turns off bottom. According to Summit, the start point is 1 1/2 turns off bottom. It will run 3 turns off bottom but it can be tuned 1 1/2 turns off bottom. It is right now, 1.75 turns off bottom and the tune performs as per the owners manual.
So far, so good. I checked the EGR, and it is new and functioning. I checked the PVC and it is new and functioning. I checked all the hose connections and they are new, some a little long and I trimmed them down.
It feels like I wanted it to. Running around town today, the gas guage did not move so I already have better fuel mileage. We probably did not put over 50 miles on it but it would have moved before. Going to the taller rear gets better mileage but it presents other issues. Once it gets going and it is sprite off the line with little pressure, it really wants to run.
so far, so good. Thanks for the pointers, they helped me with all the overall settings, and timing. I should have done it by ear from the first place.
Would roller rockers do anything besides lighten my wallet?

Viking and streets, this guy is good. Somebody need to get him on the payroll. why didn't one of us think of bumping the timing up 2 degrease and cutting off some vac. line, that was to long. I really fill like a stupid ass for not thinking of that.
LIKE I SAID, WONT NOTHING WRONG WITH THE TRUCK NO WAY!

I want to thank you guys. If it hadn't been for the posts, I wouldn't have done the thinking I did. I mean that. I built the engine in Los Angeles, we came back to Floriduh and got stuck in Charley, Floyd ,Ivan, and one other one I have forgotten the name of. We sold our house in Punta Gorda just before Hurricane Charley, went to my wife's mother's house to help her, blew the engine, rebuilt the engine, came back to Floriduh to purchase another home. Every home we had a deposit on got plowed under by a different hurricane the day before the closing!
We put a deposit on an house in Tampa and Ivan hit. The house survived! We have opened a business, got a fixerupper, and are just in shock at the chaos we endured.
You guys really helped me out. My ability to think was impared. Your help jogged me into remembering the cam. Edelbrock had a tech who never changed a spark plug working with me, we do not know any mechanics here yet, I was lost. I appreciate the help.
My van is my project van. It is a 3/4 ton extended frame, conversion van. I am a jeweler, I do not want to be hassled by people who want what I do without paying for it. We load our shop into our van every night and set up the shop the next day. No one suspects that van for anything but an hangout for freeze dried hippies.
I have modified the suspension. Teflon in the leafs of the springs, full torsion bar suspension, with lateral torque deflection. The steering has been modified. Driveshaft balanced, rear is a 2.73 posi. Th350 with shift package. 255/70-15 Coopers all around, with vintage wagonwheel wheels I found in Los Angeles. I plan on installing custom toolboxes behind the rear wheels, a pull out jewelery repair station that pulls out from the rear door, complete with jewelers bench and torches. 12V-117V inverter from dual 60amp batteries to power my Foredom handpiece. Through the side door, a complete casting setup for custom casting.
My wife has named it the Blue Barge, but, it hauled inside it, four tons to los Angeles, and four tons back, our complete household and two Bengal Cats who do not like to drive.
It will light the rear tires, both of them from a standing start through three gears in the tranny, and make it to work and back.
I like this forum. I think I will be a regular.
Thanks guys.

Originally posted by docone31
I want to thank you guys. If it hadn't been for the posts, I wouldn't have done the thinking I did. I mean that. I built the engine in Los Angeles, we came back to Floriduh and got stuck in Charley, Floyd ,Ivan, and one other one I have forgotten the name of. We sold our house in Punta Gorda just before Hurricane Charley, went to my wife's mother's house to help her, blew the engine, rebuilt the engine, came back to Floriduh to purchase another home. Every home we had a deposit on got plowed under by a different hurricane the day before the closing!
We put a deposit on an house in Tampa and Ivan hit. The house survived! We have opened a business, got a fixerupper, and are just in shock at the chaos we endured.
You guys really helped me out. My ability to think was impared. Your help jogged me into remembering the cam. Edelbrock had a tech who never changed a spark plug working with me, we do not know any mechanics here yet, I was lost. I appreciate the help.
My van is my project van. It is a 3/4 ton extended frame, conversion van. I am a jeweler, I do not want to be hassled by people who want what I do without paying for it. We load our shop into our van every night and set up the shop the next day. No one suspects that van for anything but an hangout for freeze dried hippies.
I have modified the suspension. Teflon in the leafs of the springs, full torsion bar suspension, with lateral torque deflection. The steering has been modified. Driveshaft balanced, rear is a 2.73 posi. Th350 with shift package. 255/70-15 Coopers all around, with vintage wagonwheel wheels I found in Los Angeles. I plan on installing custom toolboxes behind the rear wheels, a pull out jewelery repair station that pulls out from the rear door, complete with jewelers bench and torches. 12V-117V inverter from dual 60amp batteries to power my Foredom handpiece. Through the side door, a complete casting setup for custom casting.
My wife has named it the Blue Barge, but, it hauled inside it, four tons to los Angeles, and four tons back, our complete household and two Bengal Cats who do not like to drive.
It will light the rear tires, both of them from a standing start through three gears in the tranny, and make it to work and back.
I like this forum. I think I will be a regular.
Thanks guys.

hey docone31, youer making me fill bad now. dont let nothing i say run you off the forum.