"It just needs rings and bearings."
 

We have all heard it before, but what qualifies an engine that doesn't need a rebore with new pistons etc.
The 455 in my Bonneville was purchased from the Pontiac Dude in 2012. Ken built race engines.
It was rated at 500tq/500hp
I was not concerned about smoke on start ups.
Wiser men than me said they made it like that as the race engines are not warmed properly before being floged to death.
I found a carbie tuner that got it tuned the best he could get it.
12 years on , 28,000 miles is still hammering.
I am not flogging it ,it has not missed a beat , I have not needed to touch anything.
It's been over serviced.
It always ran rich and would foul plugs every 4000 miles when new.
Now it's fouling plugs every tank full , engine is fummey.
It still goes hard and starts first kick .
Oil pressure is high, never under 40 when hot ,180 degrees on the highway 200 in traffic.

Question is,
can this engine be freshened up on a budget and done in the home garage buy a bush mechanic ?
John L




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You are probably going to be told you need to do some homework first.

Are the plugs oil fouled or fouled from running rich?

Do Compression test before you decide rings need doing.

Did the carb guy tune it recently, or was that 12 years ago?

Is the timing still spot on? Vacuum/Mechanical advance still working properly?

Lots of small wear items that might lead to that condition, and even changes in fuel quality/mix over 12 years.

Might just need valve seals, or something way easier than a rebuild.

Rarely "needs rings, and bearings". Often needs valve Seals and valveguides.

I'm guessing its got a Holley carb on it. If so, I'd go through it first, unless the carb tuning you had done WAS a rebuild...

I would like to see some close up pics of the business ends of the spark plugs. Very possible a re-tune of the carburetor, careful evaluation of the ignition will clean up the situation. Carburetor float may be absorbing gas and making it run rich. So many possibilities. Does it smoke blue under any driving conditions? Are you ever adding oil to the crankcase? If it's not using oil, the situation is tune related. I can't imagine given the care you take of it that engine work should be needed at only 28K miles. 128K, maybe.

What ever happened to "Pontiac Dude"?
Anyone know?

I believe that that the Dude is back in business after some hard times. I can't vouch for him in this incarnation, but he did pretty well for me in 2005.

Thanks for the replies,
I will do some homework this weekend with a compression test, photos of the fouled plugs about to be changed, and I will put a timing light for reference.
Oil consumption is approximately 1 litre per 1000 miles.
The carbie is a QFT. Not sure exactly what size as my invoice states different with the documentation.
It is worth mentioning that to get the hood to close, I had to fit a drop base for air cleaner. My retired carbie guy removed the choke horn..12 years ago.
John L



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I assume QFT is a Quick Fuel Carburetor. Could you also send a pic of the carb and the intake your using. Running a 4150 based carburetor with a spread bore adapter and no choke is not optimal IMO. Making the carburetor rich enough to start and warm up decently will likely result in a too rich condition once warmed up. To start and warm-up, the engine will want 8:1 approx A/F ratio. Around 10:1 during warm up to run smoothly. About 13..5-14.5 once warmed-up. Not having a choke system means some compromises had to be made to make it driveable without that system. It's likely the plugs are being fouled every time you start and warm up the engine. Then once fully warmed, they burn off and it runs good. If you want to stay with that carb without a choke, I would try a 1 step hotter plug and use a copper style spark plug. (The cheap ones) Platinum plugs are notorious for gas fouling. This should help.

He retired and remarried. He still has the black TA

Nice to hear that.
Thanks.

I can appreciate him retiring and glad to hear that he met someone and remarried, but I wish he would still post on the board.

I've a wet day today ,so I have started some homework on PD455.
The plugs look wet and very sooty.
1 have been using up to 3 sets of plugs on rotation, NGK has always been the available brand downunder .
NGK B6S. Are what I have been using, gaped @ .45 .

I will include the build sheet .
This engine has been great and no oil leaks.
With a 3 inch exhaust, headers and 2 flowmaster mufflers it explodes into life with people standing neardy a reason to jump .
The PD455 was purchased as a ready to run drop in engine for my bonneville I was getting fixed up.
The Pontiac Dude built me a great donk as call em downunder.
I will do carbie next
JL


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Reason I mentioned the carb...Holley power valves don't last forever. The rubber diaphragm gives up, then ya got some extra fuel, ALL the time..
.

Fresh power valves would be a good maintenance item as mentioned. While you have the carb opened up, please note the power valve vacuum opening numbers and the jet sizes installed front and rear. The power valve numbers are hard to read and are on the metal part of the valve. If you see a number like 45, that means the power valve opens at 4.5" of manifold vacuum. If it says 65, that means the valve opens at 6.5" of vacuum and would deliver extra fuel sooner. If it's leaking as mentioned, the engine is seeing that extra fuel all the time. As far as the spark plugs go, a B5 spark plug would be one step hotter than your current spark plug. NGK numbers are opposite of some other brands for heat range. Higher numbers are colder plugs. Can get confusing.

Thanks Mike for the detailed response.

I will remove the carbie and see what I can find .
Can someone recommend a good YouTube tutorial relating to carbie.
Photo of a QFT card that was in my paperwork,

I am an avid reader of this forum and live in hope maybe someone has a reconditioned quadrant that will simply bolt on.
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Thanks for the pictures. That's a nice looking engine. It looks like the intake manifold was made for a square bore carburetor as I don't see any adapter. It appears to be a double pumper 750 CFM carburetor. That is a nice piece and the jetting doesn't seem way out of line for your engine. There are a number of people on this forum who are much more qualified to comment on the specifics of that carb. or any 4150 style carb. than me. But nothing looks outrageous. In my opinion, not trying to be too critical, that carb is not the ideal piece for what you are doing with your car/engine. A big, heavy car, automatic transmission, low numeric gear ratio would run cleaner and probably have better throttle response and overall performance with a Quadrajet carburetor. The small primaries and a working choke system would start and warm-up cleaner, idle smoother and get noticeable better fuel mileage under light throttle and cruise. The Quadrajet with it's very sophisticated primary side metering just can't be matched by a Holley style jet/power valve only metering system IMO. Full throttle, you still have 750 CFM capability when called for. The design is just perfect for a street car, though not as attractive as a shiny dual bowl Holley. Your Quick Fuel carb without a choke and with mechanical secondaries would be excellent for a light car, stick shift and lots of rear end ratio. It is basically a competition carburetor slightly de-tuned for street use.

If you stay with that carburetor, replacing all the rubber parts and gaskets, should help it run better. If your compression tests come out good I would consider changing the intake manifold to a spread bore design with a really good Quadrajet before even thinking about overhauling the engine. I bet you could make that all happen without spending much $$ at all. Once your happy with the new induction system you can probably sell the intake and Holley to cover all the costs! Won't look quite as sexy, but will run great.

Agree,
A Quadrajet or Cater Thermoquad (Carter) would be much better.
Ask Cliff to chime in on this.
Don't know if he still builds Qjets.
https://cliffshighperformance.com/

Or Carbking
https://thecarburetorshop.com/

I did a 'ring and bearing' rebuild of a SBC 383 5 years ago. The rings were worn out due to over-rich conditions from the PO. Not a lot of miles on the engine....195 psi in every hole but 35% leakdown in every cylinder. The bores were fine but glazed and the pistons, cam, lifters, and timing chain were like new. The bearings were also fine, but I replaced them anyway. Had the block surface-honed with a guide plate by a machinist, the rods checked, the assembly balance-checked, and the heads freshened up, all for $700. I did the assembly and measuring afterwards and it was spot on. The original 389 in my '66 GTO is about to undergo the same process, IF, and I mean IF, the bores are still in spec. It runs great, but burns oil, mainly past the valve guides on de-cel. But at 58 years old and 114k miles, may need an overbore, etc. Measurements of the internals and cylinders is critical.

Thanks for the replys,
I did a compression test with my $25 kit today.
There are some differences in psi.

I am warming to the idea of replacing the existing QFT.

I will look for qjet carbie second hand .
I need to do some research.
I might advertise for a carbie in parts wanted.

Also the height of the high-rise intake makes it a hassle with hood fitment. Air filter not getting good air ,the lid for air cleaner is very perforated with not much filtration. The hood sits on top of the lid.

It was asking me to cut a hole in the hood. That was never going to happen.

Thoughts on compression numbers,
I'm hoping not to rebuild. The new carbie set up is a cheaper option .
John L.

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