1964 Pontiac Grand Prix Re-rebuild 389 to a 455 HO

4000 rpm shouldn't have hurt it.

"Dragging brakes" ? That might smoke the brake shoes at 75 mph but I can't see it breaking the crank

Or is that another typeO ?

Another thing is that it may have been damaged during the antics from an earlier time, not necessarily when it broke.

 

Not with an automatic trans especially .No way to send a shock load back into the engine from the rear brakes.
Mr. 64, I believe I'd find someone trustworthy ,that knows Pontiacs well, and stick with that shop.

 

Dragging front brakes after the disc conversion. I think it was creating an over heating problem and a major strain on the engine. As far as someone that know Pontiac's around here they have all died or moved away. I'm still looking. And trying to learn so I can do it myself. Then I have no one to blame.


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If you want to really find out about Pontiacs, you should check out the Performance Years site and check out the "tech forums". You can find out anything you could possibly want about Pontiacs there.....(IMHO)!

 

Awesome thank u!!


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Got to hear the 455 fire up today. It sounds good!! Anyone suggest taking it to a dyno shot to have them tune it?


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ABSOLUTELY! Gary

 

Dragging front disc brakes would not cause a crank failure. Take that broken engine apart more and especially take a look at the crack surface. See what caused it to initiate.

On the new engine, dyno tuning can only help. Nice looking car you have to put the engine into!

 

thats a Nodule Iron ( ductile , SGI) crank and them are hard to bust , and were it broke is not a machining defect , more of a handling defect ( someone dropped it and didn't see a crack ) or someone hit it with a sharp object and caused a stress riser to form or a small grind with stone or file will do it too . I would have to see the surfaces of the broken parts to determine were the crack started , and it looks like there was some rust forming in the crack so it might have been there for a while more than likely someone didn't do the ring test to check for cracks in the counterweights or didn't mag it at all or properly ( some shops if they use a shot cleaner to clean there cranks they can peen over cracks and they do not show if the mag machine doesn't know how to set it up to look for them .

 

I had a 71 T/A with a 455 H.O. perfect engine for that big G/P lots of torque

( needed money for college )

455 H.O. heads along with the 455 S.D. heads were from the Ram Air IV family 4 round exhaust ports and
2.11 intake /1.94 exhaust
Pontiac engines will run all day at 5000 rpm the main webs in 455 blocks were built like a battle ship

 

My 72 heads are d port and I'm ok with it because my headers are d port from the 389. Picking up the car Monday! I'm stoked!!!


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Thanks stumpy unfortunately it was a costly mistake. Can you walk me through replacing the crank. I talked to the shop and they said I need new caps with the new crank and they have to be machined to fit the crank. Is that the best route to take?


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find a new machine shop that doesn't fleece people and doesn't talk out there ass ( try to find one that deals with rebuilding Pontiacs as a specialty A Pontiac IS NOT A Chevy ) . unless the cap was damaged ( cracked , burned or torn up from a spun bearing ) there is no reason to replace them , we cut some material off them and then align hone the bore to spec , the new crank should be stock OEM Dia , and you use the bearings or grind/polish the crank journals to fit , not the block, the block crank bore is one size . ( except the difference in oem 3.00 vs 3.25 dia )
you can use another used cap from another motor ( align boring will be needed to do this) .
if your going to rev the motor to 5500+ on a regular basis then we would say replace all of them with steel caps ( pro-gram engineering ) and stud the lower end , the Di ( OEM) caps and bolts are good for stock and ocassional racing
a align hone might be in order if the mains were pounded out of shape when the crank snapped ( I would have it done as a precaution , and if the use of the block is high milage or unknown before the original build ), a good machinist can put a line bar across it to see if the mains are out of alignment real quick and if it needs it or not . Pontiac blocks are real stable compaired to Chevy .
but if you do have to replace caps ( damaged cap ) , you have to line hone the assy and that has to be done by a shop that knows what they are doing as they have to pull the cap alignment pins , close up the old alignment holes in the block , set the cap and drill new alignment holes thru the new cap into the block then do the align hone procedure ( YOU have to have the alignment pins to prevent the caps from walking and fretting the block ) . also if you go from Bolts to studs on the mains you have to align hone the mains . but other than the material removement on the cap face to do the resizing no other work is required .

 

Again thank you Stumpy.
The shop subs the alignment out and they did tell me removing material and then realign hone the bore. It would be great if the shops around here had as much knowledge as you but I have found that when they hear pontiac the price goes up and I am lucky if they speak English. I hate learning by trial and air with shops it has cost me a lot of money and almost made me say screw classic cars and go for a new car with a warranty but I'm trying to hang in there! Thanks for taking the time to share your knowledge I really appreciate it! If you know any reputable place is Orange County CA it would be very helpful! I do plan on selling the 389 but I'm going to get it fixed right so I don't put bad Karma out there to bite me in the ass!


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if you want a reference for a Good Pontiac machine shop . try the "performance years.com" foum and ask there as they eat , drink, sleep , the later Ponchos and can line you up with a good shop on the west coast .and there is one shop that the pontiac guys will steer you away from in the valley , I will not mention names but the PY guys will .

The guy I would have recomended closed shop last year he was right in the Long Beach area .

I would not work with a shop that subs out work , as your paying higher prices and any conversations or work orders can get screwed up in the process and parts can get lost or damaged in transit by a careless employee , try to find a shop thats full service and has all the machines and can do it from the ground up . a good machine shop will charge the same if it was a Pontiac or a Chevy ,

 

Theres a pontiac builder in Grand Terrace. Rock and Roll engineering. Check out his web sight http://www.pontiacpower.com/

 

Take stimpy's advise......"if you want a reference for a Good Pontiac machine shop . try the "performance years.com" foum and ask there as they eat , drink, sleep , the later Ponchos and can line you up with a good shop on the west coast .and there is one shop that the pontiac guys will steer you away from in the valley , I will not mention names but the PY guys will" .

 

LOl... see word gets around ...

 

It's possible the shop has already taken material off the caps and they know they shouldn't take more.

 

Thanks guys!


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Good news is she is home and very happy with the 455. I'm not blown away yet cause I can't really get on her. I was really happy with the 389. It was a beast so I hope I'm impressed after I do the first oil change and can actually get on it. Anyone have a rev limit suggestion?
Please don't burn me at the stake for painting everything black


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52-5500 max for a short burst , unless it was balanced then its about 6K . 455's are not a high rev motor . a 55 has a lot of mass in the lower end ( the 4 bolts of the H.O. Help hold it in place , and the reason why we convert the 400 to a 455 with a crank change as its a lighter assembly ) . but the thing was built for torque not RPM . try to keep it under 4000 for the first 1000 mi. . its ok do a few sprinted take offs to get the rings to seat . but space them out with 25-30 miles between them helps cool the motor down . try to keep engine braking/ down hill coasting to a minimum so it will keep the ring grooves clean as they will suck oil till they are seated and that promotes coking .

nothing wrong with Black , my street motors were this color to confuse guys what was under the hood . and trying to find the Proper metallic blue was a PIA around here .( plus the fact I had several years with the several different blues . ) the motor in my 50 is going to be the green they used back then .

 

Check with board member Tom S on the PY board, he's in Long Beach. He's done a ton of high end Pontiac builds and will be able to point you to a good shop. I think he posts here from time to time as well, but don't know what screen name he uses here.

 

You'll love it.

 

I almost had a heart attack yesterday. I went outside after a couple days of rain and it looked like my car was still wet. I looked closer and they aren't water droplets. There are tiny bubbles in the entire paint from front to back. Out of no where I was told the paint was 6 years old when I bought it. It's been in the rain before with no issues and all the sudden solvent pop everywhere!!! I was ready to set the thing on fire! But then I thought wait I have i have insurance!! I called and filed a claim and it's going to be a 500 dollar deductible. They sent me to a shop in there network to get a quote. Mind you I hate dealing with paint after 2 horrific experience on on my 47 plymouth and the other still I progress nightmare on my 61 f100, the shop they sent me to wouldnt do a quote cause they can't pull the car up in there system. I was told by the adjuster if I don't want to use the shop they suggest, and I don't, they will cut me a check for the estimate and pay the shop I want to use directly. So I stopped by another shop that my mechanic suggested and the guy does some really nice work. He said it has to all come apart and go down to bare metal. I said I don't want to pay a dime and he said he would deal with the insurance company. So fingered crossed I'm getting a new paint job. I have never used my insurance for anything in my life I just pay the bill. It's nice to know they take car of this kind of stuff. Specially when the paint shop was talking numbers like 15k!!


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I got the typical insurance move from safeco. My bank sent me a new credit card in the mail 2 months ago out of the blue due to a security breach. I informed the insurance company of the new card and made payment in October. I told them that I wanted the new card to run automatically. For some reason it didn't run last month. I was assigned a new adjuster all of the sudden and she told me the claim was not valid because they backdated my insurance to November and I was not covered now due to not making a payment for December. I told her the situation and she basically said too bad and they cancelled my policy and would not let me renew it. Thanks Safeco. I got a quote from Hagerdy for about a quarter of what I was paying safeco.


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