Fixing Up 1976 Buick Junkyard Engine

Hello everyone. I, just recently, bought a Buick engine at the local junkyard. The engine is very rusty looking, but runs smoothly. Before installing it in my car though, I would like to replace the plugs, ignition cables, distributor parts, water pump, and timing chain.
Now my questions. I know that the 1976 engine is the one with the bad heads and low compression, but there don't seem to be many parts for it on summitracing.com. Why wouldn't a earlier timing chain fit a 1976 engine? It seems like the chains on summitracing are only for older 455s. Same thing for the camshaft. For earlier Buick 455s, I see plenty of them. However, for the 1976 engine, nothing. Do the parts switch over even if summit says they don't?

(http://www.summitracing.com/parts/edl-7840/applications/make/buick?prefilter=1)

(http://www.summitracing.com/parts/cca-96-203-4/applications/make/buick?prefilter=1)

 

Try RockAuto they will have those parts, 75 and 76 are the same for sure...

 

Thank you for the link. They seem to have lots of parts. As for the timing chain, would it be safe to replace the timing chain with this one?

http://www.summitracing.com/parts/edl-7840/applications/make/buick/year/1975

 

Thanks for telling me about TAperformance. I had never had trouble with summit before, but after seeing this website, I see that everything I could need for the engine is there.

 

Well. It has been a really long while, but tomorrow, I am finally taking the engine to the shop.Everything seems to be going smoothly. The engine will be swapped into a 1985 Oldsmobile Delta 88. I do have some questions though.

I saw a cam on TA performance that I liked (http://taperformance.com/proddetail.asp?prod=TA_212-455), but the website says "9.0:1 or more CR". With the 1976 455, would this cam be out of the question? If so, which cam, if any, would be recommended for more power with the OEM heads?

 

While summit racing is a great store, be careful on their website looking for Buick specific parts, ALOT of Chevy/Pontiac/Olds along with Buick parts are all clumped together like calipers, alternators, timing chains, etc.
Some parts ARE NOT Buick specific, such as the calipers, and alternators, BUT timing chain/gears are:grin:
So you have to know what your looking for.
Take Larry's advice and check out TA Performance, they are Buick specific:TU:

 

Read #31 then go back and read the whole thread(forget about the miss problem).

http://www.v8buick.com/showthread.php?249150-My-455-backfires-when-accelerating-hard

Everybody wants a (relatively)big cam but doesn't want to back it up with the necessary parts/compression. Worse yet they don't want to rev it up to the point where it actually makes more power. They want to shift at 4800 rpm and make more power.

If you don't change the heads from the crappy '76 models to the '74 and down heads you'll have 7.5:1 compression. Change the heads and at least you'll be in the 8.5:1 area. Don't waste time on machine work for the '76 heads.

'76 heads use the TA RV12, earlier heads use the TA 112. Plenty of low end from both and they will pull to 5000 rpm. Even the smallest performance cam has 10* more duration @.050" and noticeably more lift than the factory cam on tighter lobe centers. That is why even a "small" performance cam will give a nice power boost and widen the power range compared to a factory cam.

The TA 212 cam has 25*+ over the factory cam. And people wonder why it looses bottom end without the right compression ratio and equipment to back it up. Consider the manufacturers recommendations the minimum you need to work decently.

Make sure you check the crankshaft endplay on that era 455.

 

The bottom end is all the same from 70-76 isn't it? Can you explain why you said to check the endplay only for that era?

 

I am running a Comp Cams 268H cam in my 75 455. I have the stock HEI, an Edelbrock Performer intake, and new timing chain and gears. It works great as it is. Sure, it could be better if I changed the heads and all kinds of other stuff like some may make you believe has to be done, but mine is a nice streetable engine with more than enough power for my purposes. Before you're changing all the stuff I would make sure it runs well and has good oil pressure.

 

I've seen the thrust going away on some engines and others have seen it too. I'm specifically talking about the newer engines built, as in 1976. Not every engine built but too many to be co-incidence. From my understanding Buick knew the 455 was going away after 1976 so they never bothered with updating the tooling which was wearing out toward the end of the run which caused poor machining in some blocks. If you do a quick thrust check on one of the "bad" engines you'll know in a flash it is bad.

I would agree that if you have an engine that is working fine and you don't want to pull the heads off and it is making enough power for your needs then great. My main point is don't waste machine work money on those heads. If they don't have to come off for any reason, so be it.

However I would never go near a 268H in a 7.5:1 compression engine. There is no way that engine is happiest with that camshaft. If you were to do a DCR check on that camshaft in that engine it would probably make you cry with the low cylinder pressure. The good news is you probably can run 87 octane. I'd run the Comp 252 which has 206* of duration @.050" on intake and exhaust or maybe the TA RV12 which is 205*I/215* @.050". Both offer noticeably more lift than the factory cam and around 10* more duration than the factory for a nice power gain while keeping the low end torque especially when compared to the 268 and they will still run out to 5000 rpm as I've said previously.

Here's a tip for anybody that wants to listen: Run a 1" 4-hole spacer under the carb to pick up low end torque. 2" if you have the hood clearance.

 

I don't really give a crap about a number, I care about the seat of my pants feel, and how it works and runs. I have tons of low-end torque and my truck works great just how it is. I highly doubt it would be more responsive with that much less cam. To each their own.

Where are you getting 7.5:1? I had read that the 75-76's were higher, I thought.

 

75-76 had bigger chambered heads, 78cc volume, which lowered compression. 67-74 big block heads all were 71cc or under, with 70 being being 66cc for Stage 1 and 69cc for std 455. All 67-69 heads were 69cc.

Here's a handy chart: http://gasalley.thetumbleweeds.net/tech_archive/buick/heads.htm

 

The '75/'76 455's were rated at 7.5 to 1 comp. Actual compression may be lower.
'75/'76 455's were rated at 205 hp and 345 tq, pretty pathetic for a 455, but that's on par with other big blocks of the mid 70's, yep, the big block was going bye bye

 

If it was my motor, at minimum I would put a set of earlier heads on it if everything checks out good.

 

Hello everyone. Sorry for the late response. I was out of town. Based on most responses, I see I should not get a biggish cam for my low compression engine in order to have a broader power range.

So, would I be ok with the TA112?

If not, I guess I will wait until my budget allows for new heads. Right now though, with the engine out of the car, what would you recommend I replace in the engine before putting it in the car? And what would increase performance a bit?

Do you know if the edelbrock performer would be a direct bolt on with the 76 heads?

 

If you determine the TA 112 suits your needs, I have a brand new one for sale, if interested.

 

The 112 cam is 210*I/215*E @.050" which means it has 5* more intake duration than the RV12(205/215) but it is still noticeably smaller than the 212(218/230) so if you get a decent deal then go for it. Remember you will need some new lifters to go with it. Make sure you lube it up well and break it in right at startup. I'd say there is a good chance that the cam is mild enough to get away with the stock valve springs up to about 5000 rpm. Worst case an upgrade to the valvesprings can be made later.

As far as the engine goes there's not much to do if the heads aren't coming off. I would definitely drop the oil pan to make sure there is no junk in it. You have to do it carefully. If you can set it up on an engine stand or lift it off the ground however you can. Do not rotate it around so the oil pan is up. If you do that the possible junk in the pan will drop right into the crank area. Drop the pan while the engine is right side up and then you can flip the engine upside down. Check for suspicious stuff in the pan.

About the only performance thing you can do to the engine is block off the heat crossover in the middle of the heads. If you plan on cold weather driving drill about a 1/4" hole in just one of the four plugs. If you don't care about how it runs until it warms up and for the coolest intake don't drill any hole.

Run a 1" 4-hole spacer under the carb. I recommend this to anybody that doesn't have at least a 12 second car. I ran the 4-hole on my Edelbrock B4B right down to the low 12's in my heavy car where it ran at least as good as the open spacer. After that it becomes a toss up but you don't have to worry about that for now.

The Edelbrock intake will bolt right up to your engine. If you don't have a Performer yet shoot for the B4B. Depending on how the wind is blowing it may be worth a smidge of performance over the Performer but not worth worrying about if you already have the Performer.

Of course get the carb set up right and also the ignition timing. See Larry's thread for setting up the timing.

Remember everything adds up, even the little stuff.

 

I agree with the others-mild cam with more lift, better (earlier) heads if they have to come off. I once had a GS with a 'Hemi Killer' 241-241 in it; it had no low end torque and only started to pull above 3500 or so. Even with nearly 10:1 compression and headers it was wrong for a stockish build and 2.93 gears. A smaller cam got me my torque and driveability back and no loss of E.T..
Patrick