Final Straw

Alright, first what is up guys, I know it is coming about being a fair weather 73 guy. Most of you know the whole deal with the car, and I finally got the exhaust put on it and sure enough got it home and the put the vacuum gage on it and it was bouncing bad. I pulled the specs of the cam, will place below, as you know my wife got me this car back in 2005 while I was deployed. I spent countless hours while on R&R to take care of one thing after the next on it.

The motor is brand new, I mean I did not short change anything, and had a 30 year mastertech build it, so I did the best I could to take error out of it. This cam was the only thing that I had put in hopes to increase power, but brothers I am at the end of my rope. I don’t know if I needed to change the height on my pushrods, or maybe, hell I have no idea. I did not set the timing yet, I have triple checked my firing order, but each time it add a sound. Brothers, I just spent over 800 to have my exhaust put on, to trailer it home, and hear this, I only had 50, yes fifty miles on it in the eight years I have owned it.

Sometimes you have to cut your loses and move on so if you know anyone looking for one, that is serious, we might be able to work something out. Yeah I know some are going to get on here and bash me for flacking out or whatever, and sure go ahead, but at the end of the day if you cannot get a return on investment you have to slow down and think about it.

Don’t get me wrong I love the car, my wife surprised me when I got back. I have dumped end money taking it down to the frame and back up, but when you think about driving it off a bridge, you might want to let someone else enjoy it more.

Cam int .280,/ valve int .485 /advdur 284*timdur int 208*/ open -3*BTC close int 31*/over lap 62*/ center 107*

Maybe I am the jack@ss and bought a bigger cam and yes I failed to mention to the Mastertech the size, well because he is my Dad and I didn’t want him to swap it out for a RV cam, I mean it only came out with a factory 177 HP, that is not fair to her.

IF anyone knows of a fix

OK, what engine?

I'll assume 351C 2V.

If so, those cam specs aren't insane and shouldn't cause much of a problem.

Is the gauge bouncing only at idle?

Does it run on all 8 jugs and smooth out with RPM?

Any backfiring or "chuffing" out of the carb or exhaust?

You mentioned timing... that'll cause poor idling if not correct.

I'd look first for a slipped intake gasket, or bad carb base gasket.

If all is well, then I'd look into a flat cam lobe or bent pushrod/incorrectly seating valve.

Bottom end malfunction is unlikely.

Gotta isolate the "objection" first. Shouldn't be tough to diagnose. Take your time... do ONE test at a time.

Have you pulled the valve covers to check everything out yet? could just need the rockers adjusted if stud mount or shimmed/different pushrods maybe if pedestal mount rockers. I would pull the valve covers and take a look, good luck.

I am not sure if the carb or my big HEI dis, I know I know, is causing a issue, the gauge continues to bounce I started with 10-15 and kept pushing backwards to around 5-7. I can hear that rocker starting to get louder so I will be taking it off in the am.

It was back firing prior to exhaust but no issues with that as of now, I feel dumb but it is dumbing what looks like oil out of the exhaust just more black residue than I would picture normal looking like. Also sorry it is a 351C 2v.

All eight are running but as it idles sounds like it is lacking either fuel/ air. Carb is the only thing not brand new, so I might need to get it swapped/ rebuilt to know for sure.

I set the timing to 8 with a concern of going 10. Thank you very much

There isn't enough information in the post to come to conclusions.

A bouncing vacuum gauge is going to point to valves not sealing all the way, on paper. But, other things can cause a similar bounce such as being too lean or rich at idle.

Now you mentioned black coming out the tail pipes.

A couple of things, are you losing oil ?

Have you pulled the plugs? What do they look like?

Did you try a compression check? A leak down test?

It could point to issues with the valve stems, or the valve stem seals or pistion rings.

I had a situation with Teflon seals being massively defective. It contaminated my plugs, lost a lot of oil and caused ignition misfire problems.

I had to swap to viton seals to solve part of the problem.

Now you mentioned a hei ignition. Are you running spiral core wires?

Spiral core wires can almost simulate retarded ignition, the can cause tons of issues.

On the plugs, are you running a hot enough heat range? The problem is you might now be able to tell if the plugs are contaminated.

Adjusting the valves might be on the table. Do you have solid lifter, hydraulic lifter, flat tapper, rollar rocker?

There could be adjustment issues with the carb also.

You can have a situation where you have 4-5 simultaneous issues that are adding together driving you insane. I had an issue like that.

I had valve stem oil leaks, killing my ignition, ignition wires causing problems, a lean condition, an exhaust issue, a spark gap and heat range problem, vacuum advance tuning problems, and some other stuff I don't even remember at this point, it all added up and took me 4 years to figure out one piece at a time.

If your rods are a pinch too long that can lead to the valves not fully sealing on the compression stroke.

I would start with setting initial timing to what the cam specs recommend, usually around 10 degrees and leave it don't touch it, then start looking at other problem areas. If your having lean misfire or ping detonation problems don't touch the timing right away.

Again need more information to start to lead you In the right direction.

Another example on my car, fresh rebuilt engine, less then 1000 miles I'm noticing I'm down 1 quart of oil each week, start ups I would have a huge cloud of black smoke. From day 1 it never ran right. Plugs always fouled , low vac 8hg,

At first I tuned the hell out of the carb and managed to get the vac up to 12-13

Still major problems, ditched 8mm bs wires which advanced engine timing, finially I locked down my floating initial timing issue. Plugs still fouled and massive engine detonation. Figured out problem I with valves adjustment and Teflon seals falling apart , contacted engine builder and got Into a year long fight with the jerk.

He finally fixed it, engine vac up to 14-15hg. More tuning by me, plugs white for first time. Exhaust problem found, which uncovered even more massive lean ping detonation issue... More tuning hg up to 17hg. Finally I was able to fine tune,,,, 4 years later it was insanity.

I am not sure if the carb or my big HEI dis, I know I know, is causing a issue, the gauge continues to bounce I started with 10-15 and kept pushing backwards to around 5-7. I can hear that rocker starting to get louder so I will be taking it off in the am.

It was back firing prior to exhaust but no issues with that as of now, I feel dumb but it is dumbing what looks like oil out of the exhaust just more black residue than I would picture normal looking like. Also sorry it is a 351C 2v.

All eight are running but as it idles sounds like it is lacking either fuel/ air. Carb is the only thing not brand new, so I might need to get it swapped/ rebuilt to know for sure.

I set the timing to 8 with a concern of going 10. Thank you very much

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We all get that feeling from time to time.

Ask most of us if we do what we do for a return on investment and the answer is no.

You obviously have the passion. You have climbed Everest with the car and you're 50 feet from the summit and you throw your hands up and say "I've had enough" guys.

This is how we all see your situation.

What does dad say about all these niggling teething problems?

I would've thought that he could figure these out fairly easily given his experience.

Sounds to me like it is running too rich for sure

rings have to seat and with only 50 miles on the motor, they may need a proper run in. I agree, get some help setting the valvetrain and timing to base specs and run it for a few hours then worry about vacuum and Carburetor tuning

If you have shaved or surfaced the heads? An equally sized spacer needs to be placed under the rocker pedestal to make up the difference and permit valve closure. Just something to think about.

well I found out what it was and posted the pictures on the, I am scared to put a cam in her" , I wasted three lobes on that cam