Hello guys, I took my cutlass supreme in to the shop (one that was recommended by a member of this group) it was blowing blue smoke when you started it up and when you hard accelerate. Plus the number 5 cylinder kept fouling out. I checked compression all were 175psi. The previous owner put a cam in it. Also the motor leaked oil all over the place. The shop does a leakdown test and some other test. Determines it would be best to do a complete overhaul on it. I agreed. I have only had this car a couple of months. It will be my wife's daily driver during the summer months. So I'm not looking to build a race car. So I agree to. .030 over pistons and all new what it takes to have the motor tight not burning oil and leaking oil. This shop does all of their own machine work so no sending out to another shop. Also the shop is pulling and re installing the Motor. I was given an estimate of around 3500.00. Basically drop car off pick up drive away all brand new overhauled motor. My hands never get dirty. My question is, a buddy of mine says that is way to high. Is he right? Or is he out of the loop?

 

It depends on the extent of the rebuild, what their labor rate is . I have 3500 into my 355 in the engine alone but it's on the edge between street and strip. I think if the shop will do a stock style rebuild for 3500 it's a good deal but you have to find out what you are getting and make sure they tell you and explain to you what needs to get done and why along with visuals of it. For all you know they are just going to fix the oil issue and re gasket they whole engine and call it a day.

 

I haven't been to the shop to check progress. I was told. Pistons, rings, valve guides,bearings, turn the crank if needed, rear seal, timing chain, all other seals and Gaskets. I'm sure I missed a few things.

 

$3500 is VERY cheap for that much work, especially removing and installing the engine. One BIG problem is that the new pistons and head gasket are going to DRASTICALLY lower the compression and the power. Depending on the mileage, you might consider a good valve job instead.

 

X2 on what captjim said.

If the compression is that high and even it is likely a high compression 4 barrel motor that is not terribly worn. A rebuild without the same high compression pistons combined with the thicker head gaskets is really going to change (lessen) the sound and performance. Could the oil rings be clogged or bad? Yes but the problem is more likely in the heads with those compression numbers, specifically valve seals and guides.

FWIW, consider fixing the oil leaks and having a thorough valve job done, while leaving the high compression bottom end alone.

 

I didn't end-up going this route and don't know about this company. Maybe some others on this site have had experience with them, (Tuff Dawg).

http://www.ebay.com/itm/OLDSMOBILE-3...9d126d&vxp=mtr

 

Yes, you have good compression for a 10.25:1 engine there.

If they put in current aftermarket components, as they would be expected to for a mere $3,500 (yes, that is a CHEAP rebuild), your CR will probably drop to between 7.5:1 and 8:1.
If you have a cam in the engine, the engine will suddenly run like crap because the cam will need more compression than that to work properly.

Overall, I would say that a). Yes, it is a good price, and your friend who says it's expensive is nuts, but b). You are getting what you are paying for, which is a cheapo rebuild that will make you unhappy.

I agree with the others that with those compression numbers and symptoms, the problem is more likely the heads than the pistons / rings, so all you probably need is a valve job for much less than $3,500.

What were the results of the leakdown test?

- Eric

 

I agree that the bottom end is probably fine. I'd do my own diagnostics on the engine. A small puff of smoke on startup is nothing to be worried about. Your compression seems good.

 

Make sure you ask for the Speed Pro 6cc dish forged pistons, part number L2321F30. It will give you mid 9 to 1 compression, much better than 7.5 to 1 cheap cast pistons give with their 24cc dish. I believe you need a minimum .004" piston to wall clearance with the Speed Pro forged pistons.

 

3500 thats not a bad price for a complete rebuild,but like others have said unless you know what type of pistons will be used it will not be the same engine.With that being said it needs to be disassembled and cylinders-pistons measured and evaluated to determine the repair required.Most likely cylinder heads will need complete valve job and hardened exhaust seats.

 

Hardened exhaust valve seats have been proven unnecessary for regular driving, but if they've got it apart, they "Might as Well."

- Eric

 

Since the compression is good, consider leaving the heads on to retain the thinner head gaskets, replacing the valve seals, valve springs (they are not expensive), drive it and perform several 1K oil and filter changes with a high detergent oil e.g., diesel rated version and see how it reacts. Some quality fuel/intake cleaner or a ring freeing additive may also help.

Blue smoke on start up is classic valve seals and the smoke on hard acceleration may just be in the exhaust area from the leaking valve seals or an intake seal when the camshaft was replaced.

 

Ok now you guys have me all worried.. I felt confident. Here were the exact symptoms. When cold and start woth choke the engine smoked pretty good on the drivers side bank. It was a mosquito sprayer when you jumped into the accelerator. Like I said I checked the compression myself. I took it into the shop the guy said on the leak down test the number 5 cylinder which was the same one that was fouling out must have a broken or cracked ring. Which was causing the oil burning problem. I thought to myself before I took it in that all it would need is a valve job. Since the compression readings were so good. I also told him I wasn't looking to build a race car I at least wanted it back to where it is. So I assume it will have at least those compressions when it is done.. I will call Monday and get more details.. Now I won't sleep the rest of the weekend.

 

Piston choice is vitally important.
Your original 10.25:1 pistons had a dish of about 5cc, if I recall.
The low-compression motor that year (9:1) had a dish of about 14cc.
The next year they had to drop compression further, and went to a 24cc dish, which led to about an 8:1 compression ratio.

The "standard" pistons available through the usual auto parts suppliers (instead of restoration and hot-rod suppliers) are all 24cc.

In addition, the original compression gasket is about 0.016" thick, while the standard replacements are about 0.047" thick, a difference that will take about 0.5:1 of your compression away, even if all else is left the same.
If you need to pull the heads, and you want to keep the original compression, you need to have the heads milled to remove the difference in thickness, or use an expensive hot-rod gasket, like a Cometic, but even those only go as thin as about 0.023", if I recall.
Some people have trouble running pump gas, and are happy to drop the CR half a point, but that is a different story.
In your case, you say you've got a cam, so if the cam is properly suited to your current engine, it probably will not be if you end up with 24cc pistons and thick head gaskets.

While it is possible that you have a cracked oil ring, your compression is obviously good, and, frankly, it may be possible to replace the damaged oil ring assembly and leave the nicely broken-in compression rings alone.

- Eric

 

To add to the above, they also have a P/H of 1.595. On my 355, the pistons sat .053 in the hole.....

 

UPDATE:I called the shop, they were aware of the larger dish piston versus the shallower dish pistons. They had already ordered the higher compression poston. I said well that is good I didn't want it running worse then when I brought it in. They said, that definitely wasnt going to happen. I feel better now.. :-D when I get it back and Im happy with it. I will give a shout out to the shop. I definitely won't be slamming them though. I don't believe in Internet bashing a business.. Once again guys thanks a lot. It turns out I had nothing to worry about.

 

Excellent!!

Sorry if we sounded alarmist, but we regularly hear horror stories here.

Sounds like you're getting a good deal for the price so far.

- Eric

 

Hmmm, me thinks 3,500 is a little too high for an engine rebuild. I yanked the motor out of mine, threw it into the back of my truck, and took it to North Topeka. When the shop had a chance to break it open, they called and said that the two rear pistons were eaten up, the crank was shot, (they think that the dumb*** that put the motor back in didn't get the crank to torque converter/flywheel lined back up properly, thus, causing the crank to have extra pressure applied to it), and it was about to seize up. When I told them to go ahead and rebuild it, they put in a new crank, two new pistons, and put in the CompCam and new lifters for a grand total of....*drum roll*.....1900.00. Not sure of the final number, but I know it was under 2,000. Runs like a brand new car now.

 

That's apples to oranges it sounds like yours was just repaired. Parts alone on a rebuild for the shortblock with new pistons and cam are in the 1000 ball park. Then 700-1000 for machining on the block. That's shortblock alone !

 

Then add some for a valve job and the labor to remove and install + incidentals. I think $3500 is cheap.

 

3500 is what I spent on my 355 and that was with a swap meet shortblock that went bust because it needed a balance and a block. So it was the same as if I started with new pistons and a fresh block

 

Don't forget the price of a full gasket set, as well as main and rod bearings, and the labor in disassembling, cleaning, hot tanking, pressing pistons on/off rods, and reassembling.

- Eric

 

That's. Where I saved money as I cleaned my own block at my dad's shop and assembled the engine my self. I belive engine asembly runs in the 800 range and my parts est. Was based on my exprience that covered all the gaskets etc.

 

Then the maw's kick in and new carb new hei dist. , headers, wires, water pump, converter for the new kick *** cam etc etc. It snowballs.

 

The previous owner already added HEI, eldebrock performer RPM imtake, eldebrock 1806 AVS carb, and headers, so those MAW are already taken care of. The headers though are pretty rusty and leak. So I think I MAW while the shop has it out put some new ceramic headers on.

 

Jmo those 1806's suck. I had one and just junk. I had tried it after I had had a 1405. The 1405 box stock fed my engine well into the low 13's at 103 mph in the 1/4 I would sell it and get a 1405 50 cfm less than the 1806 but much easier to tune . Rebuilt units from edebrock are much cheaper than new and just as good.

 

I agree when I bought the car the carb was way out of whack. Previous owner said he jist gave up. I took it to an old school carb shop they got it close but I still wasn't completely happy with it. I'm seriously thinking of going to one of the TBI Efi conversion systems.

 

The AVS carb is a decent carb cause you can adjust the vacuum secondary's.

 

I know once the motor has been rebuilt. The carb os going to have to be re adjusted again. I'm already cringing at the thought.

 

I used a 1405 BOX stock all I adjusted was the idle and it worked very well in my 9 to 1 combo and my 10 to 1 flat top combo both 350's.