Quenton Member # 1274 posted January 31, 2004 01:14 PM ------ Dan -
What rear end gears are you running, and did you advance the cam at all?
Q
TOHCan Member # 3011 posted January 31, 2004 03:29 PM ------ And what were you running before the change, and exactly how does it differ/disappoint?
Q, I went with your suggestion on the rear end gears and put in an Auburn posi with 3.55 gears. I love the gearing. The highway is no problem (TH-400) and when the engine is running well (very finicky) I'm happy with everything. I'm not sure if the cam is advanced.
When I bought the car it had been rebuilt to have low compression to run 87 pump gas...it had zero power; had 6x-8 heads. The car came with the original intake and 62 heads.
I had the engine rebuilt, bored .040, crank needed to be turned .010, and everything mic'd to produce 9.5:1 compression so that I'd have no problems running 93 octane. I put in a 068 cam and changed the ignition over to electronic (Pertronix). I got a date correct Q-jet. I had the heads done by a shop that I hadn't used before and I'm not really sure what they did to the heads; I really wish I had researched more about head work before having them done.
So with everything rebuilt I did the recommended break-in, taking it easy for 250 miles and then gradually moving up from there.
This all happened in September; it was chilly sometimes. On a cold morning if I set the choke the car started right up and when warm would run alright...except with an extremly high idle.
When warm I had to give the car 1/4-down gas pedal to get the car to start...otherwise it would just turn over and over and over. When it started up there was tons of black smoke (fuel) and whenever I revved it up there would be black smoke. Mechanics finally pointed toward Q-jet. It was rebuilt twice and was marginally better. Finally found that the top plate (horn?) of carb was bent from over-tightening bolts at some time. Engine builder machined it flat and this made the greatest difference. With this change I had the timing reset and carb adjusted and now at least I got a good slow idle out of it. Still needed to hold pedal down to start it up. Around this time he did a compression and leakdown test: all cylinders have 150 lbs. and don't leak down less than a pound or two.
Over the last couple months there has been grey smoke coming out on startup in the morning and at the end of the day after work. It's not using a lot of oil but the best the I can figure is that the heads are leaking oil down through the valves. The engine builder said he had his machine shop check out the heads when they mic'd them and they looked alright. He said that there is a chance tranny fluid is being sucked in and being burned at startup???...this sounds weird. The problem has been getting progressively worse.
I really think it's the heads. Here are the line items on the head work receipt; I gave them the correct springs for the 068 cam: 16 valve seals - $1.92 5 freeze plugs - $2.50 16 valve locks - $8 Valve job - $75 resurface - $45 magnaflux - $18 clean rocker arms - $5 Total - $143
I took the car to a guy that is closer to my house and deals with classic cars often. He thinks the problem is the heads, particularly a valve guide or two.
I'm thinking to make it worthwhile to get the heads off and take a look at them I'll go ahead and have some porting done and get a multi-angle valve job along with the other work.
I'm confident in the bottom end of the motor. I'm less confident in the heads and carb.
The smoking is a problem. The power isn't what I expected. If the engine doesn't fall on it's face when I goose it (happens most of the time) then I can get about 1.5 rotations of the tires. I thought they'd spin a little more. Once the engine does get revved up it takes off pretty well and chirps the tires when it shifts to second (I don't have any kind of shift kit).
