Macadoo

Ahh, good to know. Thanks guys. Sometimes it's hard to distinguish between real-world reality and internet hype.

Macadoo

I'm still struggling with whether or not to rebuild the short-block. I cleaned the carbon form the ring at the top of the bore and the ridge is so thin, as in barely there. And in places I don't feel one at all (although that's a small percentage of area). There is some discoloration of course but nothing that seems alarming. I realize the picture doesn't help you "see" how small the ridge really is...but we like pics, yes?

[IMG][/IMG]

I went ahead and wiped off the thin layer or carbon from the piston tops using carb cleaner. And just for good measure I turned the block upside down and sprayed the carb cleaner around each piston, to flush out anything I got up inside there. And then I oiled everything. My one mistake was that I still need to clean the head gasket surfaces so I'll probably be doing the flushing again

coppercutlass

A re ring kit I think is in the 300 ball park figure. Then you can buy a 3 stone hone just to put a nice crosshatch pattern into the cyl. Then with some shoe laces you can polish the journals with some 400 grit crocus cloth. I wouldn't worry about sending the engine out to freshen it up. If everything is in good shape and nothing is alarming I think it's something you can tackle with out sending it to the macine shop aside from maybe hot tanking and cam bearing replacement.

MDchanic

Okay, we're at Page 9 of this saga, and I had honestly forgotten how this story started, so I've reviewed it, and have pasted highlights below.

You pulled this 8.5:1 compression 350 out of a '71 Cutlass with 52,000 miles on the clock because it leaked and you felt that the 120 to 160 psi span of compressions (unchanged with addition of oil) was too wide for you.

You found an engine that was exceptionally clean inside, with a less-than-paper-thin cylinder ridge, and disintegrated cam sprocket nylon teeth, and are planning to send out the heads to have the valves ground and to install a new cam, timing set, and gaskets.

You are now wondering whether to mess with the block further, or just to let it be.
As far as I can tell, you have no intentions of racing it, and no aspirations to high power output.

67CutlassFreak keeps telling you to do a total rebuild.

From everything I can see, it looks to me like you have an excellent, well maintained, low mileage engine, with very little wear.
My personal advice would be to not mess with it further.
There is no reason to believe that there is anything wrong with the bearings or the rings; you have good oil pressure and it doesn't blow smoke.

What I would recommend is that you decide what type of head gaskets you will be installing, get their thickness (probably about 0.046"), measure the thickness of your old steel shim head gaskets (probably about 0.016"), and have the machine shop remove the difference (probably about 0.030"), or possibly a wee bit more, from your heads.
If you don't do this, your compression will drop from somewhere between 8 and 8.5 (the original spec is usually a bit optimistic compared to actual measurements) down to about 7.5 to 8, which will affect performance.

Other than that, I think you're good to go.

- Eric

Macadoo

Thanks Copper, you're advice is always enlightening. But I've made a decision.
Eric kind of hit it on the head (pun intended, lol) when he mentioned the low compression pistons. I'm going to stop with the head work and all the new parts I already have, button her back up and install back in the car. I'll pick up another motor and build it into the engine I want while enjoying what I have. You always seem to have something laying around. Maybe this Spring you'll have a short block with high compression pistons you don't need

coppercutlass

I always have stuff specially during swap meet season. I pick up all kinds of stuff that I can either use or sell. There is nothing wrong with buttoning it up . You know what you want from your engine and for your goals I thing your fine. I just thought I would toss the freshening the short block info in there.

Macadoo

Whoa, geez Eric, putting all that together was a lot of work. Thanks man. And thanks for the tip about the gasket thickness. I had read that on here some time ago but forgot about it. I have the gaskets and will take them to the shop so they can make the proper measurements.
It's true, I was getting a little overwhelmed with all the opinions but finally figured out what I want to do. I've never owned a real power-house car, Although I've driven a couple, and think it's not a bad idea to start small/medium. Once I feel how this engine runs, I'll decide if I want more. I doubt racing is in my future, other than being a bystander. I did used to work the pit for my bro-in-law though when he ran his pro-street. Those were good times. But I imagine being behind the wheel is a tad different :-)

Macadoo

And hot tanking the block vs. scrubbing it again with oven cleaner is incredibly tempting. But I don't want to throw any more money at this engine.
When is swap meet season?

MDchanic

I'd say holding the fuel pump nozzle is the thing you would most notice.

At the 14-16mpg you'll probably get in this thing, it's not the greatest feeling, but change that to 8-10mpg, and the car spends a whole lot more time in the garage.

- Eric

coppercutlass

Im actually getting 10 mpg with a dp holley would be more with a vac secodnaries carb. I also do a lot of beating the crap out of my car so mpg isn't the only thing hurting your wallet. Busted parts are too.

Macadoo swap meet season is what I call winter. It's too cold to work in the garage so I buy parts and sell and trade stuff to keep my car addiction in check .

Macadoo

8-10...so, like my truck? No thanks.

Macadoo

Lol, got it.

joe_padavano

Sorry, but that is not correct. All Olds heads had induction hardened valve seats from the 1971 model year onward. This was done to comply with the then-new federal requirement to operate on low-lead (and later, no-lead) gasoline. This is also why compression ratios were dropped for the 1971 model year.

As noted, for an occasionally-driven car, it doesn't matter, and frankly, if you have the valves cut on these heads, the hardened area is pretty much cut away anyway. These are not steel inserts but simply a small induction hardened area in the casting.

Macadoo

Thanks Joe. That's exactly what I thought I had read. It must have been your post.

Macadoo

This is from last summer. A favor I did for a friend. Good thing I did, yeah?
[IMG][/IMG]

oldcutlass

Oh hell, they aren't worn out yet there is still some left.

oldstata

Lol my wife must hate swap meet season I spend more in the winter

coppercutlass

Oldstata my fiance has come to like it. Specially around christmas when money is tight it always has helped to pay bills. Right before I bought my house I needed extra money I sold a lot and I mean a lot of really good parts I had collected and we bought a nice tv and surround sound and kitchen ware with it. Even If I intend to use a part which is how I approach any part I buy if there is a need for it and I need cash it's for sale lol.

Macadoo

Lol!

67 Cutlass Freak

Eric I never said he should do a full rebuild. I just think he should go a little further so he knows exactly what he has. I have an extreme amount of respect for the guys that accomplish the most with the least amount of new parts, and money spent. Just ask Jeromy, (J-Chicago), he's an expert at this. I purchased a supposed good running used engine once, that had quite a few broken rings. Macadoo I really hope you can get this engine going again to your satisfaction on a cheap budget. I just hope you don't throw it back together and have the same compression issues. If you didn't see any evidence of a blown head gasket, or a burnt valve, I would keep looking until I found the problem. I think you may have a hard time installing the rear main seal without lifting the crank. I really don't see why you wouldn't want to remove the caps, just to check the bearings. You can torque them right back on. I do agree your engine does look pretty clean inside. Eric is right about the head gasket and compression. The other options would be decking the block or going with a thinner, Cometic brand head gasket. There is a formula I have somewhere for calculating how much you will have to remove from the intake depending on how much you shave the heads. I agree with others about the seats, don't worry about them. If you are not going to touch the short block, don't forget you can do a compression test on the engine while it's on the stand. You might want to prime the oil system for that. There's a couple venders that sell a nice priming tool for Olds, made out of an old distributor housing. The slight ridge you have on the upper cylinder bore doesn't look too bad at all. If your going to pull the pistons you might want to borrow a ridge reemer from someone. It's real easy to use. Keep plugging along and thanks for the updates.

oldstata

Yes mine too people think Iam lying on how chill mine had been threw my build. I just bought her a Buick for a 100.00 that needed a motor found one for 300.00 finished it yesterday lol only thing is I want to sell her current daily to pay for my paint job and she want me to park the truck

Hey check out the wall if shame I think those rotors will find a new home

MDchanic

Except that if you shave the 0.030" difference off of the heads, you'll be right where you started in terms of height, and won't need to change anything.
You could probably take an extra 0.020" off as well, and still not change anything, but I forget the rule of thumb number for how far you can go without worrying about intake surfaces and pushrod lengths.

I agree that it's a good idea to pull at least some, if not all, of the caps and get a look at the bearings.
If his ridge really is thinner than a sheet of paper, he should be able to get the pistons out without having to ream the ridge, so that's one less thing to go horribly wrong.

- Eric

Macadoo

Freak, no worries man. I appreciate all the input...from everyone. Just like this...

"I think you may have a hard time installing the rear main seal without lifting the crank. I really don't see why you wouldn't want to remove the caps, just to check the bearings. You can torque them right back on."

Are you saying I could pull the crank without removing the pistons? Or at least prop it up some to change that seal? I was under the impression, (maybe something a friend said 30 years ago), that one should never pull the caps without replacing the bearings.

Oldstata, I kept those rotors for a while but eventually tossed them on a local iron pile. What's the wall of shame?

oldstata

Its a thread look it over it's a wow

https://classicoldsmobile.com/forums...495#post608495

MDchanic

It's okay to pull the caps and reuse the old bearings, especially if they look great.
It's also okay to change them while you're at it.

The crank can usually be removed with the pistons in the engine, but it is not a job for the weak-hearted, or rather, reinstalling it isn't. The crank can just kind of squeak by with the pistons in, but just barely, and at the risk of scratching the journals with the rod bolts.

I have changed the rear main without removing any rod caps - you just have to loosen the main caps, and you can get the back of the crank up about a sixteenth of an inch, which is enough to squeak the old seal out and a new one in, but I don't recommend it if there are other options.

- Eric

Macadoo

I suppose if I cover the rod bolts with fuel line or something then the crank wont squeak by?
I'll see if I can get that seal out without removing the crank. If I really can't then I might be looking at a different ball game. I certainly didn't come this far to have the engine leak oil. What about, if it comes to it, removing the caps on both the crank and rods and pushing the pistons up to the top of the bores? I think it's a bad idea to hand me a ridge reamer.

pogo69

Mac i would pull the main and rod caos and check your bearings i'm involved in a teardown myself and am disapointed with what i found on some rod bearings and i need to do some measurements, but at any rate i wouldnt of found if i didnt take it apart you have come this far so it would make sense to double check bearings maybe plastigage,if doing the rods its better to use sacraficial nuts for the testing

Macadoo

Oh hey Pogo, I was wondering how yours was going. Sorry to hear you have some bad bearings.
I get what your saying but I really don't want to put any more money into this engine. I may look for something with a little more compression. However, if I get the main caps off and things look sketchy, I may have to reevaluate. And the timing isn't great. I'm heading into the final stretch of the semester so I'm a bit stressed and tight on time. I get a few days at Thanksgiving and may wait to make the decision until then. After I decompress a little, ya know?
I am curious what you mean by sacrificial nuts. I mean I think I get it but can you be more specific? Do they need to be actual rod bolt nuts?

MDchanic

It won't cost anything to pull the caps and look at the bearings, and if you're careful and behave well, it should all go together fine.

It's very reasonable to Plastigage each journal, and won't take too long.

As for the pistons, if the ridge is as you describe, I'd bet that you'll have no problem getting them past.

- Eric

Macadoo

Plastigauge it is. Specs in the manual?

MDchanic

Wellllllll... It's like this...

It seems as though the consensus in the Olds world is that these motors like about 0.003" at the mains (more if you're racing), but the manual says more like 0.0020-0.0025".

If they're anywhere around 3, you should be good, but I'd recommend talking to some of the more experienced engine builders around here, such as Mark, who sold you the cam.

- Eric

Macadoo

Thanks Eric. I'll send Mark a PM and post back here.

Professur

Some short sections of rubber tubing over the bolt threads before you flex yer muscles will keep everything safe.

Macadoo

So I was goofing around on Craigslist and found a set of these, new in the box, 8 of them, for an incredibly reasonable price. I don't suppose they would fit my 71 CS 350? It says for the W-31 "with outside air induction" but I thought I might get lucky.

http://www.summitracing.com/search/y...yword=L2320F30

If I can't use them I'll pass them along to the group. They're a good price.
They are .030 over in case I need to bore the block.

Tony72Cutlass'S'

Aren't those just flat-top pistons?

I wonder what your compression would end up being if you used a thicker head gasket, didnt mill your heads, and installed these pistons...

0.046" (new head gasket) - 0.016'' (old head gasket) is around 0.030...

From what i gather a standard bore is 4.057 so...

4.057 * 30thou is = 0.38781 cubic inches which means you'd be increasing your combustion chamber by around 6.36cc

whats the dish in 1971/1972 pistons? something around 6cc? then you'd be golden.

coppercutlass

Depending on the cam you got .,too much compression can lead to preignition . Just make sure you talk to mark about something like bumping up compression with your cam grind and make sure you can achieve a safe compression ratio with what you are gettin.

Macadoo

I read that the 71 #7 heads are supposed to have 64cc chambers but that they can be closer to 70cc. Makes it kind of hard to do the math. I don't really want more compression than maybe 9 or a little more. I'll talk to my head-guy once more people chime in here.

coppercutlass

Then maybe using a thicker .040 head gaskets. Will be the way to go and no head milling.

coppercutlass

I did some math . With the flat tops .030 , .025 in the cylinder appx. 70 cc's, and a .040 head gasket compression is in the 9.6 to 1 range.

MDchanic

Mac, how much do you want to complicate your life?

- Eric