Firebird Nation banner

455 help

3K views 43 replies 5 participants last post by  455_Dave 
#1 · (Edited by Moderator)
OK so still being on the fence about keeping the car but still gonna start fixing it. The motor has a bit of a tap on the passenger side and when I changed the oil the oil in the filter looked kinda like anti sieze I had my boss take a look at the car and see what he thinks since he has built 3000+ HP motors he said it sounds like a lifter has eaten itself. Now I known its not hard to change them pull the intake and pushrods out and pull them out lube em up and slide the new ones in. But I'm worried about the camshaft lobes is a lifter was stuck or something it may have damaged the cam I was told the car was cammed but honestly don't believe that so to the previous owner lying about everything else. But it does have a vacuum tank to make pressure for the booster so it may be cammed. I can get a cam and lifters from jets for a couple hundred bucks but if I'm going to put another cam in I want it to be more agrressive. Any recommendations would be greatly appreciated or any thoughts on what should do I also have to change out the qjet or rebuild it.
 
#2 ·
For a budget, Look at the Summit 2801 or 2802. 2802 will make a healthy 455 for sure. Does sound like a lifter/cam Check the rockers too, Make sure there all tightened properly. If the heads have screw in studs, Change them to ARP 7/16" studs, like $70 or so, and get Polylocks to eliminate the bottleneck style adjusters and make it a true adjustable valve train. Of oil was bcolor you describe. Possibly wiped a cam lobe. You can not use off the shelf oil in a flat tappet engine anymore. You need to add ZDDP. Oil is not the same as it was even 5 years ago. All new engines are roller. Prev owner might have used cheap oil, not knowing, which will harm cams. If cam bad, flush block. I used Kerosene on mine, Made a oil pump prime tool from a chevy dizzy, Or can buy them there cheap too. Flushed the whole oil sys with Kero first, New filter. CHanged filter, Flushed the Kero out with cheapest junk oil I could find, THEN filled with good Oil with ZDDP and only after that, did I install NEW cam. Sounds like a lot, but it is easy. Also, putting a strong magnet on side of oil pan by drain hole will help too. Catch any leftover metal. Then pull the magnet off just before you drain oil at oil changes, And metal will go out the drain instead of around and around the block
 
#3 ·
Thanks for the quick reply I do have a priming tool from when I build my 392 for my 79 Cherokee chief so pullng the 455 apart won't be a big deal to me the car runs great just has a slight tapping noise that goes away when revving off idle I put 15w40 shell rotella in the car I've used this oil onf tons of applications and seems to be a pretty damn good oil so hopefully that will be OK for it my boss said if I'm building a performance motor I should use 20w50. If I'm gonna pull the offers I may as well put a more aggressive cam in them at least I know what the car has in it. I'll check the valve lash on all the rockers to its possible that it may not be a lifter that's its just a loose rocker or pushrod slapping around. Now I have a general ideal on how to set valve last but not 100 percent sure do I adjust it with the valve open or shut? And I know to warm the motor up first I'll have have to put a tach in the car so I can break the came in properly if I Put a new one in. I know when adjusting the valves you turn the pushrod with your fingers and tighten the rocker down til you can't turn it anymore then back it off a 1/4 turn but I've never done it before so I'm not sure. I'll have to do this with my 392 as well since I never adjusted them lol. I'm only 23 but have been working in a speed shop most of my life and trying to learn even more then I already know.
 
#8 ·
I'll check the valve lash on all the rockers to its possible that it may not be a lifter that's its just a loose rocker or pushrod slapping around. Now I have a general ideal on how to

set valve last but not 100 percent sure do I adjust it with the valve open or shut? I know when adjusting the valves you turn the pushrod with your fingers and tighten the rocker

down til you can't turn it anymore then back it off a 1/4 turn but I've never done it before so I'm not sure.
Nope, that ain't even close.
There are several ways to do it. Here's the way I do it. If the timing cover is on, and the dist is in and close to correct timing, with a large breaker bar, ratchet, or torque wrench, turn the crank til the timing mark on the balancer lines up with the zero mark on the timing tab. This will be top dead center(TDC) on the compression stroke of either #1 or #6 cylinder. Remove the dist cap, to see which plug wire terminal the rotor is pointing to. If it's pointing to #1, then adjust both rockers on #1 cylinder. If it's pointing to #6 then adjust both rockers on #6 cylinder. After you adjust the rockers on one cylinder, rotate the crank clockwise 90 degrees. Then adjust both rockers on the next cylinder in the firing order, which is the same as a small block Chevy--18436572. You will have to rotate the crank thru 2 revolutions to go thru the entire firing order. Don't forget, the Pontiac dist rotor will turn counterclockwise--just opposite of a sbc motor.

Now, here's how to adjust each rocker. Back the lock screw almost out of the polylock nut. Run the nut down by hand til it takes the slack out of the rocker arm to pushrod junction. Then back it off slightly, so that there is some slack between the pushrod and the rocker arm. Then hold the pushrod between your thumb and index fingers, and rotate it slowly back and forth, as you slowly thighten the polylock nut with the fingers of your other hand until you feel the slightest amount of resistance to rotoating the push rod. STOP ! Continue to hold the pushrod steady with one hand, as you slowly try to raise the end of the rocker arm off the pushrod. If there is absolutly no slack or distance between the pushrod tip and the rocker arm, then back the nut off slowly until you can feel just a very small amount of slack or distance between the two. STOP ! Now, still holding the pushrod steady, tighten the nut ever so slightly in very small increments, checking for slack between the pushrod and rocker. Continue this tightening procedure til all slack between the pushrod and the rocker is gone. STOP ! THIS IS ZERO LASH !!! The pushrod will still be easy to rotate and will not be depressing the lifter plunger at all.


Now, with a box end wrench, tighten the nut exactly 1 / 4 turn. STOP ! Holding the nut in this position with a box end wrench , tighten the inner lock screw of the poly lock, tight ! Now, tighten the nut some more with the box end wrench The nut will turn a small amount as the lock screw digs into the top of the stud. STOP ! This will be between 1 / 4 and 1 / 2 turn tighter than zero lash, which is what most recommend. After you have adjusted both rockers on a cylinder, then rotate the crank 90 degrees, and adjust the rockers on the next cylinder in the firing order. Continue this until all rockers are adjusted. Again it will require two revolutions of the crank to go thru the entire firing order.

Again, this ain't the only way. But it's one way and it worked for me for many years.


http://pontiacformula.free.fr/en/allumage.php
 
#4 ·
If the heads do not have screw-in studs, I would not use a cam bigger than an 068 Pontiac duplicate. It has just barely over .400 lift, therefore will be less likely to pull out a press-in stud.

http://www.oreillyauto.com/site/c/detail/MEL0/SPC7/02244.oap?year=1965&make=Pontiac&model=Tempest&vi=1492736&ck=Search_02244_1492736_-1&pt=02244&ppt=C0146

If you do have screw-in studs, the bottle necks will work just fine with a small cam. You can buy 3 / 8" polylocks. They will work just fine on the top of the stud. I used this set-up for years in my bracket racers. The threads usually do not go all the way to the bottom of the polylock, so the bottom will go down far enuff to adjust the rocker. If not, you can use 7 / 16 hardened or grade 8 washers to take up the slack.

http://www.jegs.com/i/Proform/778/66935/10002/-1?parentProductId=827389

http://www.ebay.com/bhp/3-8-poly-locks

Now if you wanna get 7 / 16 studs, they are the same as BBC studs. If you know a BBC guy in your area, he may have some good used studs you can buy real cheap. If you act real nice, he may give you a set. Or you can buy some fairly cheap on Ebay. There are different length studs and poly locks.


http://www.ebay.com/itm/Mr-Gasket-1074-Rocker-Arm-Studs-7-16-14-Bottom-7-16-20-Top-16pk-Chevy-/200906131486

http://forums.highperformancepontiac.com/70/8495906/drivetrain-restoration/rocker-arm-adjustment-issue/

http://www.amazon.com/Proform-66936-Poly-Locks-Roller-Rocker/dp/B000CC9DHW
 
#5 · (Edited by Moderator)
what cam would you reccomend for my motor ? I know its hard to say without know every detail what I know the motor has an edelbrock performer intake manifold long tube headers full 3 inch pypes exhaust system with violator mufflers 750cfm qjet carb and I think 124cc heads cast number 51 the motor i think is a 1975 Pontiac I know its a 455 for sure but don't know what else I'd need to know motor wise to put a nice aggressive cam in it without having to rebuild the whole motor.
 
#6 ·
With those heads I'd look at the summit 2801 cam It's a 068 similar grind IIRC. What Don said about the rocker studs too. If there Pressed in, then I wouldnt run to agressive. Also, Rotella now has changed too. No where the Zinc as it used to. Not even sure if it's enough for flat tappet cams anymore. I would be adding additive, Or go Royal Purple HPS oil. RP Makes 3 grades, API, with some, but not enough Zinc for larger cams. Its what you will see on the shelf, As the ZInc content is mandated lower now. HPS Has a lot more Zinc, great for performance engines, And the XRS Which is a full Race oil. I run the HPS in my 455. Also, they make a great Breakin Oil, which is the only dinosaur oil they make, even though it says Synth, it's reg oil, with great amounts of zinc for helping break in the new cam and engine. I'm just gone through my breakin, Putting HPS in today.

First thing, Pull the valve covers, Check to see if you have press in or screw in studs. It's not that bad to convert to screw in, BUT, heads need to be removed and threaded. If it's screw in, Like stated, BBC studs work great. Like $43 at summit. http://www.summitracing.com/int/parts/arp-100-7101/overview/
 
#7 ·
I thought Pontiac went with screw in studs acroos the board in 1973 or so.......never hurts to check though. I think that the 1975 455 had like 7.6 to 1 compression with those 124cc heads. I think an 068 cam would really benifit from a bit more compression, so if the #51 heads are pretty tired, maybe a rebuilt set of screw in studs heads off a 1971 or later 400 would really complement the cam. At least your not talking a rebuilt, and since the top end is coming apart pretty far with the cam change, it's not that much more to swap the heads.
 
#9 ·
I don't agree with the rotate pushrod method. You will be able to rotate pushrod LONG after you start colapsing the lifters. I have always done and was taught to lift pushrod up/down. And with Polylocks, its easier, just turn the polylock by hand untill 0 play in pushrod and the polylock just gets resistance. Stover style nuts require a wrench and will not be able to feel when the nut just touches to take ut play. But you want to get just to the point where there is no play up/down in the pushrod. Then turn nut 1/2 turn and lock it down!. And done. I also turn engine over with breaker bar for every Cyl. Watch the Exh rocker open/close valve, then the intake open/close valve. Then 90* turn of crank and that cyl will be on the base circle of cam for both lifters.
 
#10 · (Edited by Moderator)
I have never put a cam in a low compression 455. But I've been reading a lot about cams lately. It seems that the steep ramp cams like the Comp Cams XE series and the Lunati VooDoo series are suppose to be designed to increase the cylinder pressure in low comp engines, thus increasing performance over a conventional type cam.

Here's a link to a site with Pontiac cam specs from several brands. Check out the CC XE series. With 124cc heads, the XE 256 or the XE 262 may be about all the cam it'll stand.

http://ronspontiacpa...ketcamspecs.htm

Lunati also has a 256 and a 262 in their VooDoo series.

All heads after mid '73 had screw-in studs. That's the good news. The bad news is that the 51's only make 7.6 compression .

A swap to some 6x or 5c heads will make a BIG difference in performance. They will make it around 9:1 comp. A 6x-4 off a 350 or W72 400 will make it a little over 9:1. If you have a machine shop mill a little off , you can get maybe 9.25 or so. Then, you can use a RA4 grind and Rhoads lifters. That'll make about 400hp and 500ft lbs of torque !


There are all sorts of possibilities. It just depends on how much you can spend on it.
 
#11 · (Edited by Moderator)
Damn thanks for all the help guys its nice to know there are still help full people out there lol. Well I was going to put new valve seal in the head but with the headers that are on the car I really do not want to remove the heads. How do you tell if the stubs are pressed in or screwed in? And if they are screwed in I should be able to run a little bit more aggressive cam? Sorry if this was already stated its a lot of information to take in and just dot wanna get confused. As far as compression ratio I have no idea I'll try to get all the numbers off the block and try to get a better idea of what I have
 
#13 ·
Here's some pics showing the press in studs, an overhead of some screw-ins and a close up of a stock bottle neck screw-in, which is what your heads should have left the factory with. Then there is a close-up of two 7 / 16" BBC type studs.
 

Attachments

#12 ·
I would look to see when the intake valve closes when comparing cams. If it closes soon, right after bottom dead center, then you will be trapping a longer stroke of compression, which will help increase the dynamic (running) compression of the engine. However, this is going to hurt cylinder filling at higher RPM when it helps to let the intake hang open longer. If your building a low end only engine this may be the route to go. While the intake is off for the cam swap, you can adjust the rockers while looking right at the lifters. You can see when the pushrod cup starts to push down off the snap ring for a good zero lash point.
 
#14 ·
Ya, that low of compresion, I wouldn't go larger than a XE 262 as well. I'm running a 274 in my 455, BUT, I have WAY more compression. Smaller cam with lower comp, Like Don stated, with sooner intake closing( Mines 63 ABDC!) Will help cyl fill on a low comp engine. Won't rev past 4500-5000 prob tho. But it is what it is with that comp. Can still build a great low RPM street motor for now, Till you get some better heads.
 
#15 · (Edited by Moderator)
Dave, you should listen to these guys. Don't put a nickle into those heads. If you want any increase in performance that you'll feel, seat of the pants, use those heads for a boat anchor only. they're crap.You can cam it, and waste time on studs till your blue in the face,but in the end you'll still have a compression ratio that'll run on water. Our gas stinks, but not that bad. fight the exhaust, and change out the heads to anything else. (Almost). In the end, you'll be glad you did. Then again, if it's your 1st performance car, you may not know what you're missing.
 
#16 · (Edited by Moderator)
I have an 05 srt4 that's a little over 300 HP but love american muscle I was building plates for the frame rails that are rotted and scared at what I found its much much worse then I first thought after cutting and hammering trying to removed all the rot I have nothing left to work with even the floors are much worse then first anticipated so I'm at a stand still right now don't know what to do I do not have the resources to fix this myself and don't have the budget to pay someone I may have to figure something out or get a few quotes on the repair of the rails so Idk for sure what my plans are I'd love to fix her up but don't know right now only time will tell. Thanks guys your all very knowledgeable and I appreciate everything if I can swing the budget to get it repaired I will if not who knows
 
#17 ·
Rusted out rear frame rails are sort of common on second gen 'Birds. When the frame rails rust out bad enough to need replacing, you can bet that there is floor pan rust as well. Replacing them is not that bad, just a bit time consuming because you need to take just about everything off the back end of the car down to a bare shell. I replaced the rear frame rails on my '71 T/A years ago. You need to drill out the spot welds and remove the old rails, fix any sheetmetal in the floorpan/trunk floor area, then spot weld in the new rails only in a few places. Trial fit the rear axle and leaf springs back into the car to verify everything lines up, then remove the axle/spring assembly and weld in the rails for good, then start bolting all the parts back on the car. You can order sections of the floor pan/trunk floor if there are places that need a big chunk cut out and replaced. It helps to really enjoy working with sheetmeal and a MIG welder.
 
#18 ·
You may have already considered this, but you may come out better, finding a cheap roller with a good body / frame rails, and using that car and yours to make one good car. That would save you the work and / or expense of replacing the frame rails. I hear of guys buying old fix-r-uppers all the time for less than $1000. Hey, it's just an option. I'd like to see you get a good strong car built and see if you like it. Then, if for some reason you don't, at least you'll have a nice car that you can sell, and get most of your money back.


I'll add this. About the motor, you don't need a 400hp motor to have a fun ride. You can have a low comp 455 that will burn street tires and have plenty of low end grunt. And after all, isn't that what most guys want from a street ride ? TJ had a low comp 455 in a 4-sp '73 TA. It was her daily driver for maybe 3 years or so. It was not fast, but it was spunky and a lot of fun to drive every day.
 

Attachments

#20 ·
I have all the plates made up for the frame rails but the bucket where the leaf spring sits is major issue for me I tried taking one of the bolts out and it snapped off so idk what my plans will be to fix this the floor is gone and in surprised the leaf didnt slam through the floor yet how to I do about safely reinforcing this area or will I have to cut it all out? I don't have the resources to cut it all out and buy new panels I have a few plates of steel a welder and grinder so hopefully I can make something work if I have to I'll make a whole frame out of 2x4 box steel 1/4 inch wall and tie it in to the sub frame then make mounts for the leaf spring holder kinda like making a whole back half for the car the weird part is its really only the driver side the passenger side has 1 small hole
 
#22 ·
Yep, you can see the hex part of some of the screw-in studs below the rocker arms. I can't tell for sure if those are the Pontiac nuts or the adjustable Chevy type. Maybe somebody else can make a positive ID.

Now for the Q-jet. With the motor warm and running, check to see if the choke plate is open all the way. There is a small tang designed to keep the secondary flap closed when the choke is even partially closed. With one finger mash down on the back of the secondary air valve(flap). If it won't go down at all, raise the choke flap to the vertical position, and try the sec flap again. It should go down slightly with only moderate pressure. I have had to bend the tang or the linkage to allow the flap to open.

Now, if the vacuum pulloff is working properly, it should be holding the flap closed, til the accelerator pedal is fully depressed, at which point it begins to release it's hold on the flap. The rate of release of the vac pulloff , combined with the tension of the air valve spring is what controls the speed at which the valve opens. If it opens too fast, there will be an almost instant bog situation. If it opens too slow, there will be a pronounced sluggish and sometimes erratic transition from 2 to 4 barrel operation.

Something else to check is, with the motor off, have someone depress the gas pedal fully. With a good light look down into the carb. The throttle blades should be vertical or real close to it. I've had too much carpet and stuff keeping the pedal from opening the blades fully. If the primaries are opening fully, but the secondaries are not, sometimes a slight bending of the linkage will make it better. But, be careful here. You can easily break something ! There is a modification that will fix this problem. Pontiac designed the secondaries to NOT open all the way on some of the early Birds, so they could rate the motors at a lower HP than the same motor in a GTO that year. There was a 20hp difference.
 
#24 ·
I'm not sure if this carb is original to my 455 on the side of the carb it says made for GMC so I assume it came from a 454 I'll have to get the model number from it and see. The car did come with a rebuild kit which I'm capable to rebuilding it but idk if the kit is even correct for the car do to the previous owner lying about everything else. I have my frame plates made up im just worried about the buckets for the leaf spring mounts so I'm at a stand still on that. Its bad when the plate that was previously welded there rotted away to. I used a vacuum to suck out all the mud that was caked in it
 
#25 ·
Most Q-jets that came on Chevy motors had a 90 degree inlet. Most BOP models had straight inlets. Also most Q-jets that came on Birds in the '70's, beginning with the '71 model had a BIG "smokestack" vent on top that requires a hole for it in the air cleaner base. If yours has a straight inlet, the GMC might just mean General Motors Corp. And if your air cleaner base doesn't have the vent hole, it could have come on a non Pontiac V8.

A rebuild kit must match the carb. There are LOTS of different types of Q-jets, with different types of internal gaskets. The only way to match the correct kit with the carb is to use the carb numbers stamped on it. Also some of the cheap kits came with parts that are not compatible with the ethanol in today's gas. The main items which are adversely affected are the accelerator pump cup, the needle tip and the float. The good cups are a darker blue color. The old black rubber cups won't last with ethanol in the gas.

There are several places online that sell the individual pieces and kits. O'reilly's may sell kits with the good parts. Not sure.

http://quadrajetparts.com/rochester-quadrajet-parts-quadrajet-accelerator-pumps-c-128_22.html

http://www.carburetion.com/Quads/R4accpump.asp
 

Attachments

#26 ·
Oh OK then mine is a Pontiac qjet it has the stack on top for the air cleaner and is a straight inlet. I watched a video awhile back on these carbs and the inlet unscrews from the carb is there a filter in there? I can't remember but in pretty sure I seen a filter in it in the video I watched. When I put the pedal to the floor it kinda back fires and carries on and have no power but normal driving is fine it just acts up if I floor it. Which honestly I think if the motor ran the way it should I think the rear leaf springs would have been pushed through the floor by now lol.
 
#30 · (Edited by Moderator)
I watched a video awhile back on these carbs and the inlet unscrews from the carb is there a filter in there? I can't remember but in pretty sure I seen a filter in it in the video I watched.
Yes, they come with a filter, which can easily get clogged ! Screw the inlet fitting out. Pull out the filter, spring and anything else inside, and throw it all in the trash. Clean it out as good as you can. Any trash left inside can get under the needle and keep it from sealing on it's seat. This will cause a severe flooding problem. Then put some good sealer on the threads of the fitting and screw it back in carefully, making sure to get it started correctly in the housing threads. These threads are real soft and very easily stripped.


You'll then have to use an inline fuel filter like a NAPA 3033 or a Wix 33033. Any NAPA store should have some in stock. I would use a WIDE worm gear hose clamp instead of the clamps that come with the filters. This will clamp the hose tighter, without cutting the hose like a narrow clamp can do. Some of the clamps with 1 / 2" wide bands will work great.

http://www.fleetfilt...ters/33033.html

http://www.ebay.com/itm/PER-206-USA-Hose-Clamp-Worm-Gear-Stainless-Steel-Fits-10-AN-Line-Hose-Size-6-/261304841022?_trksid=p2054897.l4275
 

Attachments

#28 · (Edited by Moderator)
OK, now most of the later Q-jets had a choke system which, when the choke was closed, would block the rear Throttle blades (butterlies) from opening. So, when this rear throttle block is in the block position, even if the gas pedal is depressed fully, the rear throttle blades will not open. This block mechanism is easily adjusted or eliminated by either bending or removing the small rod or pin which is in the rear throttle shaft.

(There may be several types of lockout systems.
All are designed to prevent the rear barrels from opening when the motor is cold enuff for the choke to be closed or even partially closed.)

You'll be able to see this clearly in the pics below. If the choke stays partially closed for some reason, the rear barrels can not function. On the HPP page there is a pic of the secondary lock out mechanism with the choke removed to get a good view of it. It's at the bottom left hand side of the page. Pic #6 on the Hemmings page shows the same pic. Pic #9 on the next link shows the lockout lever again.

http://www.highperfo...jet_carburetor/

http://www.hemmings...._feature20.html

http://www.underhood...arburetors.aspx
 

Attachments

#29 ·
You hear that sound??? That's the sound of my mind getting blown lol. Well I tightened up the rocker that was real loose and it still knocks so it may need new lifters so gonna look into it more and get the motor fixed the frame is still my major problem I'll probably pay someone to fix the frame I don't have the resources in gonna pull the motor apart and started fixing it
 
#31 ·
[I'll pull that filter and get rid of it now I have a questions about the linkage on the side that keeps the secondaries locked closed the little arm seekers screwed up I have not run the car with my super ghetto fix will doing this hurt anything? Or will it constantly open up the secondaries like this. That little arm that's tied just kinda flaps around.

 
#33 ·
I'm lookin at the pic but not exactly following your post. I see an E-Z tie around a metal tube. Is this supposed to keep the lockout from engaging the throttle shaft pin ? Also check the operation of the front vac pulloff that controls the sec air flap. Make sure it pulls the linkage rod in, to hold the flap closed as soon as the engine is cranked. If it does not suck it in, either no vac is getting to the pulloff or the vac diaphram is bad, and the pulloff must be replaced.

With the motor off, try to push the air flap down with one finger. It's spring should hold the flap shut , but you should be able to easily push the flap down with one finger. If the flap is really hard to push down, and obviously has too much spring pressure holding it closed, then you need to loosen the spring tension til the flap is easy to push down but still has plenty of tension to keep the flap closed when you let go of it.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top