cadillac 472 re/build, phase 3: doing stuff

[online170]

Re: cadillac 472 re/build, phase 2: planning and discussion

...would polishing the combustion chambers do anything performance-wise? i have a thing for polishing metals and i figure the heads might benefit from a polishing all around. i'm also eyeballing the intake to polish its runners.

First of all DO NOT POLISH THE INTAKE. The intake manifold, nor the runners in the heads. The little bumps help to atomize the fuel.


Polishing probably has benefits for high CFM high RPM applications but you'll just be hurting power.


Secondly, polishing has become one of those "hot button" items with all sorts of opinions. Do some research and you'll see what I mean.
Generally speaking;

Pro-Polishing People: Do it for keeping the combustion chambers and pistons clean to avoid detonation from glowing carbon deposits. (Notice how people did this alot in the 70s and 80s)

Con-Polishing People: Say polishing discourages a homogenious air/fuel mixture and creates hot/cold spots. They recommend sanding the piston top/combustion chamber smooth, and then hitting it with a bead blaster to give it a constant textured appearance as a Cheap alternative. The best way would be to get a coating, like the ones offered by piston companies. (Notice how all the articles for high end engine builds use coatings nowadays).


Make your own conclusions.


Heres what I did to my heads. Then I had them flowed and professionally ported. From a guy who does it for a living "anything more than 60 grit on the exhaust, and youre wasting your time. Any time polishing on the intake is wasting your time". He has done back to back flow bench comparisons to make that claim.

How they look now;

 

[G_Body_Enthusiast]

Re: cadillac 472 re/build, phase 2: planning and discussion

i looked up coated pistons and ceramics can be used all over an engine. ceramics and coatings for rods, cranks, lifters, cam bearings and much more. and i'm starting to want ALL of them. i wanted to get my exhaust manifolds coated anyway to reduce heat transfer into the engine compartment but now i can expand into other areas of the engine. i DO want the engine to last for a very long time and coatings would certainly help with that. increase efficiency and still reduce temps at the same time.

i finally got around to inspecting the spark plugs. the ground straps and electrodes look like new but the insulation is pitch black. same for around the electrode, the ground strap is brown on the end and fades to black going into the threads, the top of the electrode shows minimal carbon build up. all are autolite #66 resistor except for one being a champion #RN14YC. the electrode and insulation protruded out more on the champion.

 

[dogsht]

Re: cadillac 472 re/build, phase 2: planning and discussion

You might notice in my signature that I list working factory tach, oil pressure, & guages. (87 Olds 442 guage cluster) The tach hooked up just like it did to my 307 no modification needed. Some or all had a little switch for v6 or v8 if you get it wrong I am told its obviously off & you just switch it.

The oil pressure sending unit leaves my memory a little fuzzy but I think the Olds had three wires and the Caddy sending unit only had a two. Anyway someone said get one off a Buick 3800 series and it was a simple two option trial & error. One way the gauge will work and the other way it won't so if it doesn't register oil pressure on your gauge just swap it. The 3800 series (later Buick 3.8 V6) came in a lot of cars all through the 90s & beyond and the sending unit was used in multiple cars also. Got mine out of a salvage car & the yard didn't charge me. It worked like a charm and was always accurate. I saw details of the oil pressure sending unit switch thing on the net forever ago but have no idea where I saw it anymore.

 

[G_Body_Enthusiast]

Re: cadillac 472 re/build, phase 2: planning and discussion

i think i have the solution on the block already. the guy had some brass fittings screwed in the back where the oil pressure switch goes and i can use the 1/4"-18 1/8"-27 npt fitting to get the correct oil pressure sending unit to screw into the block. i have two such fittings so i'm blessed with a spare. so that problem is solved. the next is the coolant temp sending unit and i think i need a fitting for it also.

i cannot get the fitting off for the fuel filter inside the fuel pump. not sure if they made it non serviceable or if it's just a bear to get off because i couldnt get it to budge. the filter inside is rusty and needs replacing and i'd hate to buy a whole other fuel pump because i cant get the fitting off.

 

[Intragration]

Re: cadillac 472 re/build, phase 2: planning and discussion

Did you soak it with PB Blaster? That should help. If not, a new pump wouldn't be a bad thing, they're not that expensive.

 

[online170]

Re: cadillac 472 re/build, phase 2: planning and discussion

You got it with the coatings. The cheap way is to bead blast it. Or sand it down if its rough and then bead blast it.

When the engine fires for the first time, a very thin layor of carbon will adhere to the surface and this is your coating. If you put an acetylene torch to an aluminum piston, it will melt very quickly. Put a layer of carbon on it, and see what happens. Its surprising.

 

[G_Body_Enthusiast]

Re: cadillac 472 re/build, phase 2: planning and discussion

Did you soak it with PB Blaster? That should help. If not, a new pump wouldn't be a bad thing, they're not that expensive.

i ran out of pb blaster a week or two ago and i had already planned on buying another can of it. i just havent bought it yet.

the pump looks like new. after i cleaned it up my friend said it looks almost new. the gold iridite finish is still shiny and has complete coverage on the bottom half of the pump. i cant imagine it's frozen but then again the filter looked rusty so it may be frozen from rust. i'll probably just buy another pump, it's not worth fighting with this one.

You got it with the coatings. The cheap way is to bead blast it. Or sand it down if its rough and then bead blast it.

When the engine fires for the first time, a very thin layer of carbon will adhere to the surface and this is your coating. If you put an acetylene torch to an aluminum piston, it will melt very quickly. Put a layer of carbon on it, and see what happens. Its surprising.

i'm thinking of having the combustion chambers coated along with the piston tops (and skirts), valves and maybe all the runners in the heads. it seems like these engines run warm and cooling is something of an issue so all the coatings might help to keep the engine a little cooler but keep the combustion good and hot, a two fold benefit. i might even have the underside of the intake coated to reduce thermal transfer there. the prices dont appear cheap but not outrageously expensive either.

 

[online170]

Re: cadillac 472 re/build, phase 2: planning and discussion

http://www.hotrod.com/techarticles/engi ... ewall.html

Like this?

 

[G_Body_Enthusiast]

Re: cadillac 472 re/build, phase 2: planning and discussion

yes like that.

i need a 1/2 npt - 3/8 npt reducer bushing for the coolant sending unit and the gauge issue is no longer an issue. 4-ish bucks for a brass one from dorman. grainger has some in stainless for 20 bucks. i'll stick with brass.

i am also starting to derust some smaller parts like the timing pointer. i gave it a 24 hour bath in naval jelly and it came out looking nice. some pitting on the side that faces the timing cover but the rest is all good. now i need to finish the exhaust manifolds.

 

[online170]

Re: cadillac 472 re/build, phase 2: planning and discussion

If you like polishing stuff, open up the exit on the exhaust maniffold. You will notice its like a 2" exit. You can open it up pretty far. I just use a grinding stone and a die grinder.