I was looking at this woman's 78 olds omega. Great body, two little rust bubbles on the lower side of the passenger fender. Has an olds motor with an auto trans. On starting up the engine it was making a pop,pop,pop noise like an exhaust manifold leak. After it warmed up I drove it up and down a small road. The car felt like it was down on power and the sound had changed from a pop to a tap,tap,tap sound that increased in speed and volume with engine speed/load. It had ~25 lbs of oil pressure at 195 degrees. She wanted $2k opening price. Is it worth it? It did not sound like a rod knock, more like a tappet with a lot of play in it. I'm thinking $1500. Should I do a compression test and pull the valve covers or is it not even worth it? Let me know what you think.
the Rocker arm fulcrums are worn... this lets the rocker arms ride higher and lets them tap..i have changed 20 sets of these over the past bunch of years...you can see where if the pivot wears.. the rocker will ride higher loosening the valve adjustmenti have fine tuned the height of the fulcrums by carefully grinding the bottom off.. this requires some skill... but i have found these with grooves where the rocker arms rotate over 1/8" deep...the pivots are 3 bucks each at az... and you usually don't need to change the rocker arms.. just the pivots..start with stock length versions.. if some are still loose.. change those rocker arms only.. if still loose.. then carefully grind some material off the bases.. this select fitting is usually done on freshly assembled engines.. but don't change the lifters.. no mater what people say... its not the lifters.. its the rocker arm fulcrums allowing too much valve lash..if this is an OLDS motor.. Melling/Rocker Arm PivotPart Number: MRM-1798 Alternate Part Number: 11-25
This Omega has to be in really great shape for her to ask $2,000. Rule of thumb on a used car it takes atleast 10% of your money in repairs to fix it. Your already talking some money. A car that an older person owns does not make it a Charm by NO means....Just some advice. Been there and done that..Okay.I would go through that car with a fine tooth comb. Those old type cats are not cheap to replace. Look over the front end. You didn't mention what engine it has, or the trans. Be carefull. Good Luck....BobBob
It has some olds V8 in it, with a Carter AFB, factory air, factory intake and exhaust manifolds. Also had a column shift 3 speed auto, again, not sure what kind. It's going for at least $1500 cheaper than the next nova-type car I've seen online. There's a guy with a 77 nova, he wants $4500 and that one only has a 6 cylinder. The whole car was pretty much rust-free aside from two small bubbles on the bottom of the pass. fender. The whole front end was in great shape, no broken/missing grill, no broken/missing taillights, no rusted subframe, no rusted rear shock mounts, no rusted floorpan or trunkpan. Has bucket seats from some other car in it, the headliner is a little saggy, and it has some aftermarket steering wheel. But the dash isn't cracked, there's a trio of additional gauges under the dash, a nice radio, and a pair of Jenson 6x9's in the back. I thought it was pretty fly for $2k, especially if that engine noise does turn out to be just a few $3 pedestals.
When Bob said to check the front-end he didn't mean the grill. Check the front suspension pieces for wear, i.e.; control arm bushings, tie rod ends, idler arm, draglink, and ball joints. Anybody that has ever had a balljoint break while moving has two things, luck and one hell of a story. Replacing normal front-end wear items can get pricey ($750+/- if you do it yourself) especially if you have to pay someone else to do the work, and a front-end alignment is mandatory immediately afterward to keep it from eating tires. Pressing bushings and balljoints in can be $100 by itself at a machine shop and that's after the parts are off the car. It takes the correct spring compressor to get the coil spring back in place.To identify the Olds motor look on the block to the right of the oil fill tube. There will be string of numbers, write them down, and either a larger number or letter. Numbers are small blocks while letters are big blocks. Look at the lower front corner of the driver's side head, again there should be a number or letter. Again numbers are small block castings and letters are big block castings. Post what you find and we'll tell you what engine you have.
Okay, looking at the top of the engine just in front of the intake manifold was this "3161 GM 5.0L G"I assume that's a 307? Can anyone tell me if it's a roller block? That would be cool.Did a compression test on the engine and found each cylinder to be around 100-120 psi. With 80's cylinder heads, I think that's pretty good.Interesting note, I put all the spark plugs in after checking the compression and hooked the coil back up. I went to start the motor to try and find the source of that tapping, and after it managed to idle on its own (it needs a carb rebuild or at least a serious tuneup) it didn't make the noise. Just sat there and burbled like all good small blocks do. 35-40 psi oil pressure cold. I think maybe some foreign material attached itself to the flex plate (as there is no cover on it and it has been parked out in her yard) and was hitting the bell housing every time it came around.
The 307s had 5.0L cast into the block. The roller application started in 85 and ran through 90 when the motor stopped being produced. According to Mondello Technical Reference Manual, the 3161 casting is an 80-84 307, non-roller. The heads should have a 5A casting if they are original to that motor.