Gramma's 75 Firebird: the new project
 

It's been slow around here so we decided to do a little engine work on the 1975 Firebird that my grandmother bought new from Ruckles Pontiac in Yonkers, New York back in September 1975. My grandfather traded in a 1969 Thunderbird plus cash for the Firebird and drove it off the lot. Gramma Rose drove the car for several years and then ended up giving us the car in the early 1980's when the door just got way too heavy to pull shut. (Anyone with a second gen F-body will know exactly what I mean).

We got the car with 38,000 miles and my brother drove it for a few years til it ran up 70,000 miles. At that point it just sat around and I ended up taking it and repainting the car and giving it back to my father as a gift. He proceeded to park it in the garage and throw all sorts of things on top of it and drag garden hoses across it. So I reposessed it in 2004 and brought it back to my house.

Anyway, Since my daughter helped rebuild the engine in the 72 T/A back when she was 8, I figured it was time to let my son try his hand at rebuilding the original 350.

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First thing we did was a compression test on the engine. Here's the results:

cyl 1: 125 psi
cyl 2: 120 psi
cyl 3: 125 psi
cyl 4: 115 psi
cyl 5: 115 psi
cyl 6: 120 psi
cyl 7: 115 psi
cyl 8: 125 psi

I then sprayed some oil in the low psi cylinders and retested with negligible improvement. (So that means it's the rings, not the valves - more on this later).

Since there was more than 10% variation between the highest and lowest pressures, it was time for a freshening.

I unplugged everything rather uneventfully in a day and got it out of the engine bay with the help of the wife and the kids.

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Other than a change to a 1972 cast iron four barrel intake and a camshaft/valvespring/timing chain swap in 1994, nothing has ever been done to the internals of this 350 engine.

With the boy by my side we pulled the engine apart and did some forensic examination of the parts. I'm a firm believer in actually examining what you have as you take it apart and not just throwing everything in a pile in the center of the garage. We found some interesting things.

The lifter valley was reasonably clean with a little tarnish on everything. Cam looked fine.

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The double roller timing chain was stretched quite a bit. When you set it at "0" on the timing mark and then tried to rotate the crank, you get the mark on the balancer to line up with the "4" degree mark before the distributor rotor would move. Thats a bit too much slack.

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Pulled the 6X heads and it looked like a bit of oil was burning in some of the cylinders. If you looked into the exhaust ports you could see the oil sludge seeping though the guides.

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A bit of carbon on the pistons but the bores looked beautiful - a mirror finish with no scratches anywhere.

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The bottom end showed quite a bit of tarnish on everything, the results of years of sitting with old oil, I imagine.

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Take a look at the piston and tell me what is wrong with this picture....

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Yeah, nice factory alignment of the ring gaps. All eight pistons had the gaps on every compression ring and every oil ring lined up with each other. It defies logic. Every kid learns in high school shop class that you have to stagger the ring gaps in different locations to avoid loss of compression and high oil consumption.

All I can think is this was some type of job action or purposeful sabotage by the guy at the engine assembly plant back in 1975.

No wonder the car never had any ooomph when you hit the gas.

(Original machine marks on the piston skirts look nice, though)

We removed the compression rings and checked the ring gaps:

Cyl 1: .032, .030
Cyl 2: .032, .032
Cyl 3: .030, .032
Cyl 4: .032, .035
Cyl 5: .035, .032
Cyl 6: .030. .035
Cyl 7: .028, .028
Cyl 8: .025, .030


I believe the spec is supposed to be .019 plus/minus .010.

Main bearings/journals looked beautiful:

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The rod bearings/journals looked just as nice. Oil clearance was still within spec. And yes, I stamped each rod with the numbers. They were all unnumbered when we popped the pan off.

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It still had the original asbestos rear main seal which was leaking badly along with the timing cover seal, oil pan gasket, torque converter seal, tailshaft seal, rear pinion seal.....

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Here's the empty block awaiting a trip to the shop:

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and all the parts:

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And of course the typical monkey wrench in the ointment...cracked exhaust manifold.

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If I can't find a replacement I might upgrade to the repro ram air manifolds.

Looks good, can't wait to follow this one :)

Steve, that is a nice bird :)

Maybe I'm missing something, but that's 8% difference. If it wasn't using oil, I wouldn't have rebuilt as it's only virgin once. Bore and bearings would seem to indicate that there were no issues.

As to why it was gutless, the tiny cam they put in those from the factory is the culprit I'm sure. I hope you're planning at least a mild upgrade in that area. Very cool car.

Doh!


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I was never too good with math, especially percentages.

I also needed an excuse to freshen up the engine especially with all the seals leaking from sitting so much.

And it's a good father/son project for the summer.

:-)

Cool project, and sweet car.

I noticed that too, and thought I was missing something. LOL

I've got a few manifolds down in the basement, i'll check the #s for you ...I hope you're not going to go any further than cleaning up and freshening the mechanicals on that time capsule ....

I'm sure you know this but rings rotate while the engine is running. Believe it or not, they don't all rotate in a beautiful symphony of synchronicity. They end up where they end up. I would say it was a coincidence that they were all lined up.

I understand the rotational effect but that's just too bizarro to have the gap on every ring, on all 8 pistons within a half inch of each other. If the universe has that much synchronicity i think i should go out and buy a powerball ticket (or 8 tickets) right now. :-)

Please check, that would save a bunch of time and effort if you have something.

And yes, we are just cleaning, replacing rings, bearings and swapping in a Melling SPC-7 068 cam and reassembling. I ordered the correct 1975 blue paint yesterday from Bill Hirsch, here in Jersey yesterday. Too bad it comes only in quarts and isnt available in a spray can.

(of course, I did break off a stud on the pass manifold. Got that side, too?)

You just can't sit down & relax - can you? :noidea:

Really nice car Steve, going to be a nice little ride with the freshen-up!

You're right, I can't just sit around. :-)

It's our family heirloom. I dont know if I told you guys of this episode:

When Gramma Rose had the car she always had the strangest way of shifting the car into gear. She would be sitting behind the wheel and would take her left hand and reach all the way across her body to push the gear selector knob down on the console shifter and then use her left hand to pull the selector into drive. Her right hand stayed on the steering wheel the whole time. It was the weirdest, most unnatural action you could think of. (Any of you with an automatic in your Firebird, try it. It's just about impossible to do).

Anyway, when it was time to teach my daughter how to drive, (mind you she is named after my grandmother, her great-grandmother), she sat behind the wheel, started the car and the reached over wth her left hand and duplicated exactly, the same bizarre method of shifting that Gramma Rose used. She had never seen her great-grandmother drive the car and would not have known of this procedure.

The hair on the back of neck stood up and I swore I could hear the Twilight Zone theme playing somewhere.

I know Gramma Rose was smiling up there, too.

You might be in luck. For some reason I think these are A-body logs. I've got a driver's side 499624A, date code k124 and a passenger side 496002A, date code L034. The heat valve is in very good working order both have flanges, the one still has the head pipe attached, it was cut off at the down pipe, the crossover is still good.

Don't you just love it when that happens!

When/where do you wanna meet up? You haven't visited in a while!

Been crazy busy getting the business up and running. I think you now have an excuse to take the '72 on a road trip for ice cream and mini golf. (I have a really fun route for you to take--uses about a tank of gas lol) one way that is ;~) The logs would be no charge, almost ditched them a bunch of times, but knew there was a reason I was hanging on to them.

A tank of gas? That thing gets the worst gas mileage of any car i have!
The eight barrelled hemi with 4.10s gets better mileage than the T/A!

PM me your contact info (again) and I'll give you a call. :-)

I looked at mine. You might have to go repro.

http://www.forums.maxperformanceinc....7&d=1303404510

Must be a common flaw where they all crack. Spray it with brake-clean and see if that is a real crack or a casting line. Mine was definitely a crack.

I did spray it but with carb cleaner. Looked like a crack to me.

Thanks for checking. Yeah, it must be a common flaw.

Loaded up all the engine parts in the truck. Ready to get dropped off tomorrow. Here's a couple shots of the interior. The only things that I replaced over the years were the sagging headliner and the carpet. Everything else is as it was in 75. Including the vintage (and muddy) J.C. Whitney floormats.

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I'll double check the ones i have for cracks. pming you my cell.

Great choice on the cam and I think RA manifolds would be a perfect match if you can't find a manifold. You could always have that one repaired, pretty easy fix for anyone that can weld cast iron.

97 hits and 37 replys....I think we are in for a long ride here....

Thanks to X-bird2 (Jim) I got a good set of manifolds in my hands now.
You guys are the best!

Looking at that car, there is one thing that'd really set it off - hood tach.

Yeah, I've been thinking about that, too...but I don't have the heart to cut a hole in that hood.

Happy to have them go to a good home ...

That '75 is in great shape Steve. I'm glad to see you are preserving it.

Dang Bob...you talk with them big words real nice like.


BJ

Just dropped off the engine parts. He agreed the bores looked great...and then laughed and said "But the ridge (and the bore measurement) indicates it's time for bigger pistons." He said to blame Gramma for that: all those two mile trips to the beauty salon with the engine never fully warming up and the choke flushing all that extra gas down in the engine ends up washing the cylinder walls of oil.

So now I have to start shopping for some replacement pistons once he tells me what size we need.

Anyone have a Summit Racing coupon out there???

Spent the day cleaning the turbo 350 tranny. Since the car sat for most of its life, all the seals needed attention. I replaced the torque converter seal, the tailshaft seal and the pan gasket and filter.

Here is the rather dirty trans wheeled out the driveway after I swapped the converter and driveshaft yoke seals. The old furniture moving cart came in handy, along with some old railroad tie sections.

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I then used a spray bottle full of Purple Stuff degreaser and some wooden sticks and vinyl/brass brushes to clean all the oil, tar, mud and sand that was encrusted on the sides. Took several "lather, rinse, repeat" iterations to get it comepletely clean. I stayed away from steel wire brushes as they tend to scratch the aluminum.

Sure is handy having the cherry picker to hang the thing on.

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After hoisting the tranny up I was able to pull the pan and replace the filter. The pan looked great, no metal in there. I guess someone back in the 70's replaced the filter as there was some gasket goo on the pan gasket. The underside of the pan was pefect, flat, and scratch free, further evidence that the tranny had never been out of the car. (They usually get dragged across the floor when removed.) I was careful to not place it on the ground, in order to further preserve the pan's finish.

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Here is the VIN stamp location on the turbo 350. Happily, this one matches the car and the engine.

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All done and headed back into the garage. Last thing left to do is the filler tube O-ring which doesn't arrive til tomorrow.

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Looks good Steve. Wish I had the time and room to do a lot of that stuff!

Cleaning time. Used a spray bottle of the purple stuff degreaser and cleaned the engine compartment. Thirty six years of oil and dirt everywhere. Got most of it washed away with the garden hose.

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Notice where the exhaust head pipes are sitting? Gee, what do you think the odds are that when I went to remove the brake master cylinder, that the flare nut wrench would slip out of my hand and fly through the air and land right in the driver's side head pipe...and then slide a foot or two down the pipe...laughing at me the whole way. Nothing but net.

I had to find a flexible wire and fasten a magnet to the end and fish it down the pipe. It was like a carnival game from Hell. I finally won the game and got my wrench back after about an hour of fishing.

I pulled the front steering linkage and the steering box, just to clean the encrusted gunk off. The steering box was natural cast finish with an aluminum cover and a pink paint daub on the spline where the steering shaft mounts up.

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Dodged a bullet here! Check out the steering box bolt in the center. I used PB Blaster to loosen the bolt but it still took an impact gun to get them loosened. I would loosen, then tighten, then loosen repeatedly, to rock them free. Looks like the center bolt came out just in time. I was surprised it didn't break after seeing how much was rusted away.

The steering linkage was gunk covered and took a lot of brushing and degreaser to get it clean. You can see the original green paint mark on the driver's side, inner tie rod. (Just like my 72 T/A had). The weird black plastic ball thingy that looks like a toilet bowl float is actually the plastic cover (two piece) that goes over the steering box rag joint and the lower six inches of the steering column shaft. I think this was some kind of safety item to prevent debris, rocks and stuff from jamming the steering if it got caught between the rag joint and the subframe.

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I pulled the brake booster out to clean it up. It had quite a bit of surface rust on it. Soaking it, face down in the safestrustremover.com stuff. Working very well taking the rustiness away.

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You can see the light blue inspection mark on the "Delco Moraine" stamp in the 2:00 position on the face.

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And on the top was a light blue mark that ran across from the front side to the back side at the 12:00 position, as well as an orange daub right at the top.

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Here's the engine compartment at the moment. I ended up using a little daub of diesel fuel on a rag to clean the firewall and the inner fenders. It worked out very nicely. The dry areas you see on the driver's side of the firewall and alongside the A/C box are the sloppily-applied, factory body schutz undercoating, which I am leaving in place.

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And, yes that is a rag covering that cursed open exhaust down pipe. :rolleyes:

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Some of the cleaned up parts at the moment: the steering box, wiper motor, the steering shaft, the 7042264 1972 400 carb (matches the intake I have on the car), and an extra brand new master cylinder that I had sitting around waiting to go on something.

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My parts order from Summit Racing should arrive tomorrow so I can bring the pistons, cam bearings and block assembly hardware over to the machine shop. I ended up getting the entire rebuild kit, which includes .030 pistons, rings, cam, main, and rod bearings in one package. (The crank polished up nicely so I can stick with standard size main and rod bearings.) Since I already had bought a new Melling oil pump and a Felpro gasket kit, they were able to deduct those items from the kit and save me about 80 bucks.

Got the engine parts from Summit this morning. For some crazy reason they sent me 6 pistons from one warehouse and 2 from another. I brought them to the machinist and he didn't have a good feeling about them since they looked markedly different: an old version and a new version of the same part number. He weighed them and the weight difference was off the scale, literally.

I called Summit and they agreed that was not right - you never mix and match pistons from different sets, let alone different years of manufacture. All I can assume is that it must have been the computerized inventory system selecting the locations from which to ship. They issued a call tag for the 6+2 pistons and they are drop shipping me a new, matched set directly from Sealed Power.

On a positive note, they do have excellent customer service people, who realized the problem and took care of it immediately.

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The original block was bored .030 and is ready for the cam bearings, galley plugs, freeze plugs, etc.

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The original 6X heads are in process at the moment. Original valves were in nice shape, so we are reusing them. The heads will be resurfaced after the valve job is finished.

Gee, maybe I'll get up to an actual 8.5 compression ratio with the head shaving. I don't know if today's gas can handle all that power!

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