Richard Sweet
Well-Known Member
George, Wrong thread reply?
Rebuilt 302 casting heads available through Rockauto
- Thread starter toolmanmike
- Start date
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No
Correct thread reply, show some things how to help keep the engine bay heat down. Headers are like multi tube radiators, radiating heat up into the engine bay adding to people's engine overheating problems. The manifolds send the excessive heat out to the back of the car.
Want your engine to be running in the 180* to 200* degree range, anything more than that and you are asking for problems. Want your radiator and cooling components to keep engine temps down into the recommended operating range.
That's pretty George. What brand of exhaust? TTI?
Yes TTI
Nice fitting package, snaking around the torsions up at the front, and the X-Pipe design to get the alternating pulses from side to side to help pull out the spent exhaust gases. Dynomax Mufflers, it had flowmasters but too much drone and ting ting ting . . had to come off.
Nice fitting package, snaking around the torsions up at the front, and the X-Pipe design to get the alternating pulses from side to side to help pull out the spent exhaust gases. Dynomax Mufflers, it had flowmasters but too much drone and ting ting ting . . had to come off.
I need exhaust on my Swinger and have a pair of 68 340 manifolds on the shelf. I like the Dynomax sound.
Richard Sweet
Well-Known Member
Received the two 2D31 Famous Brand cylinder heads yesterday from Rock Auto in Houston. They were remanufactured in Mexico. Casting #4323302 on both & they look ok.
Regarding the heat buttons, if they melt at 265*F, it would be best not to cure any VHT paint applied to them in an oven, as instructed on the cans: first at 250*F, then at 400*F, then at 600*F. It would be better to wait 7 days, then cure the painted heads on the engine, as instructed. Dupli-Color engine enamel with ceramic spray cans instructions don't specify any baking or curing, so maybe that would be a better choice.
Regarding the heat buttons, if they melt at 265*F, it would be best not to cure any VHT paint applied to them in an oven, as instructed on the cans: first at 250*F, then at 400*F, then at 600*F. It would be better to wait 7 days, then cure the painted heads on the engine, as instructed. Dupli-Color engine enamel with ceramic spray cans instructions don't specify any baking or curing, so maybe that would be a better choice.
How do they look?
Yes just use the Dupli-Color aerosol ceramic engine paint, spray it on as directed. Stands up to the engine heat just fine. Air dries and no need to cure. Available at O'Reilly's as one place to get the mopar colors.
Myself being a previous bodyman / painter, I always put down a coat of standard gray primer surfacer first on the well prepared engine prior to painting. This gives the final paint a nice base to stand up on, instead of getting sucked into the roughness of the cast iron. Stands up to engine heat excellent too. Have painted complete diesel engines like this too, not a problem.
66jim
Well-Known Member
302 heads require less timing which is their biggest advantage. Back when they first appeared where advertised as 'fast burn' similar to Chevy Vortec.
MOPAROFFICIAL
Oogliboogli
They have the same size ports as any 318 head. There is no difference between them other than the closed chamber...and that aside from raising the compression a tad will only benefit you if the piston is close enough .050-.030 from the closed side of the chamber to achieve quench effect.
I'd use them to raise the comp or incorporate quench. I have a set sitting on the shelf for probably 12 yrs. I measured the chambers at 64cc. They are stock and in great shape. 124 cc int runner.
Flow 172cfm@.450-.500
They take a lot of work to make them into a 360 head. The runners are not quite as tall so the volume is never really the same as a full ported 360 which falls around 185-190cc max. Can't really get then any bigger without then being paper thin and crack prone. The 302,675,310 when flowing 200cfm ime the int port volumes are about 132-135cc and anything flowing more than 205cfm..usually is easier with a 1.88 valve and therefore ex. 220cfm =138-140cc int port. I'll add that some of the early closed chamber 273 heads are 66-67 cc from the factory.
66jim
Well-Known Member
I would say the 302 head is more application specific. Mild 318 273 street not max effort.
That is really good info and makes perfect sense. First time I had heard that angle on the 302 heads. It just keeps getting better and better. Thanks for posting that up !
MOPAROFFICIAL
Oogliboogli
Dang George,
Check it out...any closed chamber head takes less timing than an open chamber because with an open chamber=more area=needs earlier ignition to burn it in the same amount of time . Flame travel . A to b , now shorten the distance, hence fast burn/closed chamber, When they say fast burn, that's because the chamber is smaller, more compact, A to B is shorter/less distance to the plug everything's being shoved towards as well... as the piston gets closer to the closed side of the chamber the a/f does get goosed/reanimated as I like to say less prone to pre ignition as its swished towards the ignition point. The tighter you make that quench...the faster it will burn. Makes for a really efficient motor.. if you dont beat the heads up with the piston crowns..It's great stuff, needs other pieces to be fully realized of course.
However If the piston is .080 away..they're just a compression bump is all.
I may not explain it scientifically as some engineer knot head might.. but hope you get it. Lol
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I am liking that, got the 516 closed chamber heads, now with hardened exhaust seats too on this 67 383 Factory 4 bbl engine that is sitting here.
Richard Sweet
Well-Known Member
On one of the 302 heads, the exhaust gas return ports have some sort of small plug or valve in them and I don't know what those are. The other head egr ports are just open and threaded. I will be plugging those egr ports and just wanted to know what to do with the little things in the egr ports on the one head. Any ideas?
Richard
Richard
Drill them out clean with 3/16 bit and plug them with small allen plug from the hardware store. I tap the thread holes with a thread tap of the proper size. Believe it is 1/4" x 20 course thread if memory serves me correctly.
Richard Sweet
Well-Known Member
Well, duh, I guess my eyes are getting weak. They are the Allen plugs that I need. I just had to stick the right size Allen wrench in and turn 'em. So I just have to buy 4 more now. They all had what looks like soft, white Teflon paste on them, which sounds like just what they need.
Richard
Richard
Just ordered mine. Will I need to take them in and have them inspected, or are these ready to go?
Richard Sweet
Well-Known Member
I'd say give them a good look-over, clean them up and mask and paint them. If you cc the chambers, that will be good information for your engine build. If you want to see the valves and seats or the tightness of the valve stems in the guides, then you'll have to take them apart. Consult your mechanic.
When you remove your old heads, take photos of the piston at TDC and measure the distance it is down from the top of the block. Note if there any valve reliefs cut in the piston. If you have already chosen new pistons, etc., then, either way, you'll be able to calculate compression and select a cam to suit your needs.
At least that's what I plan on doing.
Did Rock Auto say how many are available now?
When you remove your old heads, take photos of the piston at TDC and measure the distance it is down from the top of the block. Note if there any valve reliefs cut in the piston. If you have already chosen new pistons, etc., then, either way, you'll be able to calculate compression and select a cam to suit your needs.
At least that's what I plan on doing.
Did Rock Auto say how many are available now?
I believe there was one pair left when I bought mine last night.
Thanks for the info, I'm currently rebuilding my 318 and haven't yet begun to put it back together. I have the bare block back from the machine shop, new pistons, crankshaft, etc. I've gotten some cam suggestions here on FABO, but do you still recommend finding my deck clearance before selecting a cam?
Thanks for the info, I'm currently rebuilding my 318 and haven't yet begun to put it back together. I have the bare block back from the machine shop, new pistons, crankshaft, etc. I've gotten some cam suggestions here on FABO, but do you still recommend finding my deck clearance before selecting a cam?
Your "piston in the hole" measurement, the bore size, head gasket diameter and compressed thickness and the chamber cc will give you your static compression ratio. That is very important information to know for the cam company guys to pick out the right cam.
nm9stheham
Well-Known Member
It is not a bad idea to check it, but honestly, for a mild rebuild like your 318, it is easy enough to compute it and it will be within a few thousandths + or -. You just add half the stroke to the standard rod length to the compression height of the piston and subtract all that from the standard deck height.
Strke/2 = 3.31"/2 = 1.655"
Rod length = 6.123"
CH for the 814's is 1.755" out of the FME catalog
1.655+6.123+1.755 = 9.533"
Standard LA deck height is 9.600" So:
9.600-9.533 = .067" down in the hole
The SCR and any DCR numbers I gave you over in your long thread are all based in this number, plus a number of other well-known dimensions. Yes, it can vary + or - a few thousandths but that amounts to + or - .05 in compression ratio....so it's not going to be ANY issue to run with that .067"-in-the-hole number for a basic engine like this 318.
FYI, you can feel a difference in your butt with a .25 change in CR; the engine will be noticeably different with .5 change, and it will be a different engine with a full point change in CR. So you can see why not to fret over .05 to.1 point differences; this is not a top fueler engine! LOL When you get to that 360 build, then it may be time to be a bit more precise.
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nm9stheham
Well-Known Member
Boy, that is a hard call to make. Thye ought to be rebuilds, but it's hard to say where they were rebuilt and so hard to say what can be good/bad/indifferent about them. Let's just hope any seats are set in better than the last set! I can see going either way here: run with them and keep your fingers crossed or have then checked over..
BTW as for cam selection, do you want to run with the valve springs that will come on these heads? Which are very likely just simple stockers. This seems like a project to build just a solid, reliable basic engine with part off of the shelf.
Thanks for the numbers! I’m gonna fold them up and put em in my pocket for safe keeping.
It’s a tough call regarding cams, part of me wants to be conservative and stick with the simple (and reliable) build originally planned, but the devil on my shoulder wants to add just a little here and a little there.
nm9stheham
Well-Known Member
It is a classic issue for 318's: the low CR limits you on cam for daily driving. If you over cam it is sluggish at low RPM's. If you are drag racing, you put in a high stall speed TC, rev it past the low RPM's before launch, and don't look back. Not the same for street driving.
And your temptation is another classic.....we've all been there! I put a biiig cam in one of my race engine for a rally car.... revved up to 7700 and past 8k RPM at WOT but dead below 3700 RPM...I mean DEAD. Not good for that type of racing application where you need a flexible engine. Similarly, I honestly think if you put in a smaller cam you will be happier.
Going up in cam lift without going up as much in duration is the better way to go. But then you run into faster cam ramp speeds and needing stiffer valve springs and so forth. So starting with low CR puts you in a corner in a number of ways.
I am going to post another cam or 2 over in your other thread that are 'in-between' what you had as of yesterday....keep the lift up, the duration down, and not be so fast on the ramps so you can use easier springs.
BTW, those CR numbers I think were based in using the standard Felpro kit 'Permatorque' head gaskets PN 8553PT. Those are a bit on the thick side. You will boost your SCR and DCR by about 0.4 points by going to Mr Gasket 1121G's at just over half the thickness. Make sure your head surfaces are good and flat if you use those, and re-torque them after the initial heat cycles. (Which I do for any head gasket...)
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