72 olds 455 problems

[deerchooper]

well things are bad. the morot has a small miss. chenged the plugs again for a fresh set from the first fire up. i did a compression test and here is what i found.

1 140 2 132
3 125 4 130
5 132 6 118
7 135 8 132

this really sucks right now.

i got a lead for another motor w/tranny for 500 and he will ganentee it.

should i buy a reman, rebuild?

what to do what to do?

i just want to drive and have fun watching rubber necks all day

 

[Hemi8me]

Rebiuld bigger!!!!

 

[42chevy]

I am looking for a 455 also and one for $500 that he will garauntee, I would buy it. You may need to rebuild your heads. Have you tried compression check after squirting oil in the cylinders? That would tell if it is rings or valves.

 

[donsrods]

I agree with 42Chevy, I wouldn't give up yet. Do the oil routine and take another compression test. If it comes up, it's rings, if it doesn't change you just need to do a valve job.

Don

 

[zzrodder]

Since #3 and especially #6 are the weak ones, how did the plugs look from those cylinders ? Like 42Chev and Don said, you may get lucky with only valve problems - if your engine had been sitting for some time, the valves and seats could have corroded so if the oil test helps you may only need to give them a good lapping in. Fingers crossed....

 

[deerchooper]

i will check with oil when i get home.

i was wondering, i have a couple rockers making noise. do you think maybe there worn to the point that that they arent alowing enough lift to build compression. since i typed that i think that wouldnt matter because you do crank it over a couple times till it stops building pressure.

 

[deerchooper]

the plugs looked all right on them cylinders. some plugs looked rich.

the motor sat inside with no carb. i just wonder if there is something inside both intake runners that might be cloggin them.

 

[deerchooper]

ok, i had the numbers off from yesterday and there were.

1, 125 2, 130
3, 132 4, 135
5, 140 6, 118
7, 132 8, 132

this is with 1 side all plugs removed, carb at idle posistion.

today all plugs removed, carb wide open posistion.

dry,

1, 155 2, 150
3, 150 4, 145
5, 147 6, 143
7, 150 8, 144

with a teaspoon of oil in cylinders
1, 162 2, 152
3, 160 4, 155
5, 163 6, 155
7, 165 8, 150

so what do i got now?

i noticed when its cold the motor at idle sounds good. then as it warms up i start getting ther lifter/ rocker chatter. kinda like the lifters cant keep pumped up or the rockers are worn pretty good.

any input?

 

[donsrods]

What kind of oil pressure do you have? Your new compression numbers aren't all that bad. I would change the oil, put a can of 5 minute flush in the crankcase, and run it for a little bit, then drain the oil and put new oil and filter on it. Could be that there is some buildup in the engine, restricting oil flow.

Normally I don't like the quick flush stuff, but in this case you might be tearing it down anyway, so one last try won't hurt. A can of Marvel Mystery Oil in the last batch of clean oil might be a good idea too.

Don

 

[zzrodder]

Don has some good suggestions, there may be some crud blocking oil flow to the lifters. Orrr - you could have some bad lobes on the cam , worn or bent pushrods, bad springs etc. Are Olds rockers non-adjustable ? Don't remember, tho they would have to be worn pretty bad to be noisy - or if they are mounted on a pedestal like Caddys, they could be worn also......

 

[deerchooper]

i have 25lbs cold and warm at idle, 40ish while crusing. the olds rockers are non adjustable.

 

[deerchooper]

ok, i replaced the points set up with one of them conversion kits. the miss seamed to leave and i got more power now, but its still not the neck snapping detroit muscle i hear of.

i took it for a little ride and it ran better. i still have the lifter chatter but im trying to solve 1 thing at a time. when i was heading back home about 35 mph i droped it into second and hammered it. it started to go up in rpm then fell on its face like the carb is dumping to much fuel. i also beleave the fancy old school air cleaner is choking out the motor. i should have taken it off for another test but it is late and i got to get up early in the mornin for work.

tomorrow is a new day, hope to get some more things ironed out with this motor. my buddy is stoping over later and maybe we can get to the bottom of this.

its a quadurjet carb. not really sure what its off of but i beleave this is the carb i had on my 396 back in the day.

also, i still feal the carb is rich. when i pop off a vac line that goes to my tranny the motor idles up about 100 to 200 rpm. so im allowing the motor to lean out a little from its rich state. right?

does anything ring a bell with the above systoms to you guys?

 

[zzrodder]

It's normal for the idle to go up with a vacuum line off, like you said , it leans it out. You may have the idle screws out of whack, normally you would start off with them 1 1/2 turns out and go from there. Lotsa guys swear by the old Q-Jets and when working right they can give decent mileage and performance plus they have that cool howl when you stomp it.
Very common on them to have the accellerator pump go bad, especially if it's been on the shelf awhile. Symptoms are just what you decribed, tromp on it and you get a massive bog. Buy a carb kit - they come with a bunch of parts that confuse the average person (me) but just take the top off and change the gasket and install the new accelerator plunger and you'll be amazed at the difference. Oh, and before you take it apart, get a can of carb cleaner and blast off the crud so it doesn't get in the carb.

 

[deerchooper]

well we came to the conclusion that the cam is shot, rocker stands are shot. i going to look at the motor down the road and talk to the guy. i want to get a feel for him and if he will write me a reciept for the garentee of the motor. if he will i will fork over the cash and put it in tomorrow night to try it out. if all goes good ill be done, if not it will go back to him the next day and i wil buy a reman engine.