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post #1 of 11 (permalink) Old 12-31-2015, 09:22 AM Thread Starter
 
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disapointed 428 build

Hello, newbie here,

I'm sorry for asking as I'm sure this is an old topic but your advice to other PMD lovers seems very sound.
I fell for the smooth talking schmuck who was more interested in my money and parts than building an honest motor. Prior to this motor I had a 70 TA with 370hp so I use this as comparison. The 68 428 I had built for my 68 GTO is no comparison to the 70 TA motor. Long story short the 428 will have to come out a second time for a rear main leak, the first was the crank hitting the windage tray, no excuse for either. Still makes me sick. I have tuned and timed it till the cows came home. New HEI, 2.5 Exhaust, Flowmasters
My question is will Edelbrock alum heads bring my motor to life?
Any ideas would be greatly appreciated.
Below is what was supposedly put in the motor.
The motor started out a untouched 1968 pontiac 428. first the motor was cleaned and magnifluxed, The motor was bored and honed out 030, fresh, then new std 455 pistons where used. new molly rings, recondition rods, new rod and main bearings, cut and polished 455 crankshaft, more torque with the longer stroke. Then new 60lb oil pump. new timing chain set, new cam bearings, windage tray, new gasket set, new lunati cam and hyd. lifters. 490 lift, 230 - 240 [email protected] .050. put on adjustable rocker arm locks, The heads where 6x-4, replaced exhaust valves, new comp springs, keepers, retainers new,pc seals complete valve job, resurfaced heads,91ccs. 1972 gto intake, no egr, to fit the heads.
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Last edited by oldgoat1968; 12-31-2015 at 09:27 AM. Reason: need mor info added
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post #2 of 11 (permalink) Old 12-31-2015, 10:34 AM
 
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"...Any ideas would be greatly appreciated..."


The 455 engine you describe should easily make 400hp and 500ft lbs of torque. It should be a real tire smoker.

If this is not the case, then I suspect it is either not getting enuff fuel/air mixture, or is not getting enuff fire at the correct time. And, I suppose that the cam may have been installed retarded.

What carb ? Have you checked to be sure the butterflies are opening COMPLETELY, when the accelerator pedal is mashed to the floor ? Sure the secondaries are working correctly(if vac operated) ?

Initial timing(at idle) ? Total timing and at what rpm is it reached ?

Most agree that the initial should be around 12-14 degrees, minimum. And usually the optimum total advance is somewhere about 34-36 degrees, reached at no later than 3500 rpm. Many think it should all be in by 3000rpm, and some, of course, like it even sooner. The correct timing curve can make lots of difference in power !

If the deck height is up near zero, you have about 9.73:1 static compression. So, you definitely need at least 93 octane gas, or maybe a little race gas mixed in.

Compression Ratio Calculator - Wallace Racing

Here is the Lunati cam, which is the closest I can find to the specs you gave. It looks like a decent choice for a 455. But, I'd run Rhoads lifters with it, to give it a smoother idle and more vacuum and more low end off idle torque and power. I like for my bracket engines to have a decent, fairly smooth idle, at 800rpm, in gear.

https://www.lunatipower.com/Product....d=1764&gid=280

So, does your engine feel weak at low rpm, or up near 5000rpm or both high and low ?

"...My question is will Edelbrock alum heads bring my motor to life?..."

You should not need alum heads. But, if the iron heads are not highly and efficiently ported, then alum heads will flow more fuel air mixture, therefore have the potential to make more power than unported 6x heads. One advantage of the alum heads is that you can run 10.5 CR without fear of detonation. Some run 11:1 without problems.

If you decide on alum heads, I'd recommend KRE 85cc D-ports.

Kauffman Racing Equipment

But, if you want a working heat crossover system, for cold weather driving, then the 87cc Edel D-ports are the way to go. The out of the box E-heads are said to have inferior parts. So, if you decide on them, most recommend that you buy some that have been built from bare heads, by somebody like Butler or SD Performance, with quality parts, and machine work. With bolts and shipping, these will cost near $3000, or even more, depending on level of porting.

Butler Performance - Edelbrock Aluminum D Port Pontiac Cylinder Heads

http://www.sdperformance.com/viewPro...productID=1823

http://www.sandovalperformance.com/#...er-heads/c1ojh

BUT, again, I say that the combo you described, properly tuned, with a GOOD Q-jet, SHOULD make somewhere near 400hp @ 5000rpm & 500ft lbs of torque @ between 3000 & 3500 rpm. If it doesn't, you need to find out why. Just swapping to alum heads alone, will not fix the problem. IMO

Here's an engine similar to yours, by a well known Pontiac engine builder.

455 Long Block

Last edited by oldskool; 12-31-2015 at 11:57 AM.
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post #3 of 11 (permalink) Old 12-31-2015, 02:48 PM
 
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To add what has already been noted by oldskool, the engine should smoke the tires.

1.) How many miles on the rebuild? Have had engines that seemed not to be too peppy when first new and then come alive once the engine got some miles on it and everything broken in.

2.) Carb size and type? Does it fully open? -look down inside with pedal to the floor. Also make sure pedal cable is adjusted correctly to fully open the carb.

3.) Did you put a vacuum gauge on the engine to see if you have a vacuum leak or if the needle fluctuates which may indicate other problems to check for?

4.) Headers or cast iron manifolds? Too small a diameter will choke the engine while too large will over scavenge.

5.) Are you using the correct harmonic balancer matched to the timing cover/pointer for your engine? You may have this mismatched which will throw off your timing if you are trying to use the factory marks. If you have the old rubber ringed factory balancer, the outer ring can slip and give a false reading of your timing. If the engine seemingly runs hot or heats up quickly, your timing may be retarded too much and this will hurt power. You may want to find Top Dead Center on your No.1 piston to verify that your timing mark on the balancer lines up with the timing cover scale.

6.) Did you degree the cam to the factory specs on your cam card?

7.) Did you make sure you have the correct length pushrods? Sometimes when heads are cut, or blocks milled, this changes the distance from the hydraulic lifter pocket to rocker arm pocket and a different length may be required. Check out this pdf here: How to Verify Valvetrain Geometry - Lunati Power

8.) After completing No. 5 above, do you have the correct preload on the hydraulic lifters? Read this: Hydraulic Lifter Adjustment This can be adjusted while the engine is running - which will get messy. Back each rocker arm off until a light clicking is heard. Then tighten until it stops, wait a a few seconds for the lifter to pump down, adjust again if clicking is heard, and wait again for the lifter to pump down. Then per your lifter suppliers spec, turn the adjusting nut (some go 1/4 turn, some 1/2 turn, some 1 turn) and while holding with a wrench, tighten down the allen screw to lock the adjusters into place.

9.) Fuel starvation, bad pump, fuel filter, kink in the line or collapsed rubber hose, collapsed sock on the fuel tank pickup tube, wrong gas cap? A fuel pressure gauge at the carb could provide info should this be a problem.

10.) Ignition problem? Even though you have a new (or rebuilt/new?) HEI, there could be a problem with it. Do you have a 12-gauge copper stranded wire that delivers 12 Volts to the terminal marked "BAT" on your cap? You don't want to use the factory 1968 ignition wire which is a resistor wire and will only give you 8 volts or so and will not provide a good strong spark. Gotta have 12 Volts. Have you verified the advance curve of the HEI?

11.) Aluminum heads will not solve the problem. Your iron head should work very well on your build.

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post #4 of 11 (permalink) Old 12-31-2015, 06:17 PM
 
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Crank hitting the wind age tray, hmmm, odd, 400-428 long windage tray is the same. A short tray out of a 455 will have a 5 embossed into it and will def have the extra clearance, if cant fiquire out what's going on with the current one.

Are the 6x-4's stock flow? Bowl hog and gasket matched with 1.77 ex valves, they should work real well. The last thing I'd do is throw a pair of 87cc round port E heads at a 433 Shortblock, leaving a lot on the table with the 87cc alum round ports.
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post #5 of 11 (permalink) Old 12-31-2015, 09:26 PM
 
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"...The last thing I'd do is throw a pair of 87cc round port E heads at a 433 Shortblock, leaving a lot on the table with the 87cc alum round ports..."


"...The motor started out a untouched 1968 pontiac 428. first the motor was cleaned and magnifluxed, The motor was bored and honed out 030, fresh, then new std 455 pistons where used. new molly rings, recondition rods, new rod and main bearings, cut and polished 455 crankshaft, more torque with the longer stroke."

According to the Wallace calculator, some 85cc KRE D-ports will give a std bore 455 just over 10:1 CR. That should be enuff to make decent power and be very pump gas friendly.

The 74cc D-ports will make about 11.25:1 CR. I'm sure that would make more power, but may be pushing it just a bit, for poor quality pump gas. I'm sure there are lots of guys who will say they have run more compression than that, for years, with no problems. So, that's all I'll say about it.

Happy New Year, ya'll !

Last edited by oldskool; 12-31-2015 at 09:50 PM.
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post #6 of 11 (permalink) Old 01-01-2016, 12:05 PM
 
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in the original post, I missed the 455 crank into the 428 block part of the build, quickly read and thought .030 428. fwiw, that's why the stock 428 long wind age tray is rubbing. it needs tweaked or shimmed up from the main caps/ or replaced with a short one with a 5 stamped into it.

Have had such "428 into a 455" shortblocks built before, was basically a way to move what used to be common as dirt '69 YH 428 blocks (and keep the 4" stroke cranks for other builds). I've always been long on good 455 cranks and such builds made a good way to put '69 and earlier Pontiac owners into a 455.

On an .030 428 block with a stock stroke 455 crank, had one built in the late 90's for local customer with 87cc stock E heads. The shortblock was professionally machined, bored, then honed with a plate. Eagle rods, common and cheap, but heavy TRW's. What amounted to the Edelbrock performer performer rpm package cam, i.e.; RAIV cam (231-240 on a 113), with Performer RPM intake, tuned 850 Holley, rhoades lifters were also used. With headers, on the engine dyno, the engine made a peak of a little over 430 hp. I know the local shop that dyno tuned the combo wasn't impressed, neither was several of the partys involved.

Having been fortunate to drive several RAIV cars, a fresh bone stock RAIV 400 is going to pull a whole lot harder from 3500-5800, than the above 430 hp 9.75-1 455, that's just the nature of both engines. If that's what the OP meant by a 370 hp 400 being more impressive, I'd totally agree, but if I was sticking the eheaded 455 in a cruiser with 2.93 or 3.08 gears (not me!) and just had to have those shiny alum heads, well I might actually think the the low end torque of the eheaded 455 was sufficient.

With the loss of heat with the alum heads, a full more 1 point of compression can be tolerated with the same fuel. I'm not sure how many of us would set pat, building a 455 and limiting its compression ratio to 8.75-1 with iron heads, but that's basically what one is doing by limiting an 87cc round port e headed 455 to 9.7-1 CR. Now take that same short block, what amounts to a std bore 455, build it with forged pistons with a D shaped dish, run the box stock 10-15 cfm better 72 cc round port E heads, raising the CR 1/2-2/3 of a point, one is going to be starting with a whole diffent animal.

In the OP's shoes, a moderate port job/ bowl hog/ gasket match should pick up head flow considerably on the 6X-4's. If funds are avail, could have more port work done and have a set of 260 cfm 6X-4's. Another alternative, and many posters here prob dont realize this, is if the 6X-4's are dated I, J or K of '77, they're of a lot more value to restorers of '78 and '79 W72 TransAms, and selling them off as freshly rebuilt stock flow heads, ought to be able to find the right buyer that will pay $600-700 or more for them. just throwing out alternatives.
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post #7 of 11 (permalink) Old 01-01-2016, 04:45 PM
 
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"...If funds are avail..."


Yeah, if funds are available, that changes EVERYTHING !!!

He can go with light pistons, H-beam rods, 80cc KRE High Port heads, thin Cometic gaskets, a good roller cam valve train, either a Northwind or Victor intake, a good street tuned 1050 Dominator type carb, Dougs headers, a well built HD TH400 with a JW Super Bell front section & correct Continental converter, HD driveshaft & rear end, racing gas, etc, etc, etc.

It's easy to build a low 10sec street car, nowadays. All it takes is the proper amount of "funds". 400hp & 500ft lbs of torque is enuff for some, but not near enuff for others. Less compression and cam will "leave some on the table" compared to more compression & cam. Stock unported heads will "leave some on the table" compared to PROPERLY ported and built heads. And, a mild or moderate build, will "leave some on the table", compared to a max power, street/strip build. So, it all boils down to what you want and how much you can spend. IMO
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post #8 of 11 (permalink) Old 01-01-2016, 06:15 PM
 
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I think the topic is going off center with the possible engine combinations that were not asked for. The original statement was: "The 68 428 I had built for my 68 GTO is no comparison to the 70 TA motor."

The Question was: My question is will Edelbrock alum heads bring my motor to life?

We then got a list of things done to the engine. The combo should work well as is, but something is amiss. Building a "new" engine and asking what parts to use to get mega HP didn't seem to be asked? Maybe I missed it.

I think solving for the diminished HP would be the first step before pulling the engine to fix the leaking rear seal. IF this proved to still leave the poor guy with a dud of an engine, then it would be time for engine pulling AND a tear down of the said engine to determine if Mr. smooth talking schmuck did not deliver the goods as promised. If he did or did not, at that point it should be determined as to what route to take to bring back the missing HP or add some.

Our aim and advice should be helping to diagnose and sort out the already built engine first and not depress the guy or frustrate him more into thinking he needs another engine rebuild or more parts to get it to run respectable.

Just sayin'
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Thank you all for your input. It looks like I have much research many more things to try before spending big bucks. Great info.
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post #10 of 11 (permalink) Old 01-01-2016, 07:06 PM
 
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Originally Posted by PontiacJim View Post
I think the topic is going off center with the possible engine combinations that were not asked for. The original statement was: "The 68 428 I had built for my 68 GTO is no comparison to the 70 TA motor."

The Question was: My question is will Edelbrock alum heads bring my motor to life?

We then got a list of things done to the engine. The combo should work well as is, but something is amiss. Building a "new" engine and asking what parts to use to get mega HP didn't seem to be asked? Maybe I missed it.

I think solving for the diminished HP would be the first step before pulling the engine to fix the leaking rear seal. IF this proved to still leave the poor guy with a dud of an engine, then it would be time for engine pulling AND a tear down of the said engine to determine if Mr. smooth talking schmuck did not deliver the goods as promised. If he did or did not, at that point it should be determined as to what route to take to bring back the missing HP or add some.

Our aim and advice should be helping to diagnose and sort out the already built engine first and not depress the guy or frustrate him more into thinking he needs another engine rebuild or more parts to get it to run respectable. Just saying'
No intention to depress or frustrate. 6X-4's are very good Dport heads, I threw out substantive factual info on the build of a stock head flow 87cc eheaded 455 as the OP asked, total waste of funds, IMHO, the OP has a good basis for a strong street engine build, and I agree more needs to done to sort it out.

As far as far as my earlier comment of as funds are avail, it doesn't cost that much to have a pair of Dports bowl hogged and one can do a good gasket match theirself. Further port work, into the 250-260 cfm range for typically another $400-500. Have no idea of who that's local to the OP could do further competant port work on the 6X-4's.

Some people on this board seem to think that one has to ship their cast iron heads all the way across the country and pay one of a handful of "boutique builders" a small fortune to perform such work. The fact is there are a bunch of racers, street/strip guys, and engine builders across the country that can do high quality port work. Same deal with very good quality machine work, there are litterally multiple dozens of high quality engine builders across the country that can build a very strong Pontiac engine.
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