I hope someone can shed some light on a few questions.I had a 283 bottom end machined for rebuilding and the machine shop also rebuilt a set of 350 ( Cast no-3947041 / 64 cc Heads ) for me .I built the engine with new pistons rings and bearings.The engine then sat for about 5 years before firing as the hot rods taken a few years to build.Does anyone know the correct plugs for these heads as Ive been running the engine with NGK-BP5FS plugs ( The car is not licenced yet so the engine has only had the cam run in an then fired and run for a while on several occations when moving it)
The plugs are running a bit rich but every time I've removed the plugs there's been oil around the threads of the plug and a bit above.I've done a compression test and all cylinders have been between 153 psi & 158 psi I could be wrong but I'm wondering if the Guides were not reconditioned when rebuilt and oil is being let into the bores.Can anyone please shed some light on the problem.
Nick
2006-12-30 00:39:07 · 9 answers · asked by fitzy 1 in Cars & Transportation ➔ Car Makes ➔ Chevrolet
Engine is originally a 283
( Manufactured between 1959 to 1962 which can be bored to 4 inch )
The engine has been bored to 4 inch and has a 3 inch stroke which makes it a 302 CID
2006-12-30 20:27:48 · update #1
It may be that it's not broke in yet & is still leaking some oil past the rings.
2006-12-30 01:08:46 · answer #1 · answered by Anonymous · 0⤊ 0⤋
Assuming you have correct jets, First, the holly... make it gone. (a little secret here, an old quadrajet,mid-to-late 60's can be made to flow up to 750c.f.m. simply be changing both the front,AND rear jets, later models did not have replaceable rear jets) Second, a 650 is too much for your poor 283(I love 283;s, done many of them), a 500, maybe even a 600, with a little extra porting, and slightly more than 'mild' cam, but not a 650. A good set of headers will help scavenging the waste output mix, do not forget a crossover pipe here. Back in the day, it was common to use larger exhaust pipes(progressively), but the progressive use of smaller pipes is growing in popularity( the belIEf is that this speeds up the exhaust flow due to more restriction, ie: same amount of exhaust- smaller pipe= exhaust has to travel faster, I am not sure of this myself, being old-school). Kinda got off the beaten path there for a moment, sorry. You may want to recheck your heads, I assume you had them magna-fluxed, if not your valve seats/valves may have issues. hope this helps, and I am not clouding the issue for you. OH, you may want to recheck your valve seals also.
2016-03-29 00:49:06 · answer #2 · answered by Anonymous · 0⤊ 0⤋
283 - 3.875 bore X 3.00 stroke
283 - bored .060 = 292 CID
302 - 4.000 bore X 3.00 stroke
307 - 3.875 bore X 3.25 stroke
327 - 4.000 bore X 3.25 stroke
350 - 4.000 bore X 3.48 stroke
For you to have 302 cid with a 283 crank you need a 327 small journal block.
The DZ302's were large journal steel cranks and made their power at 7000 rpm.
Your guides may have been ignored or may have been knurled.Usually guilds will make the motor puff blue smoke just on start up , then quit. I would not worry yet . Run it for 500 miles and see if its still a problem.
2006-12-30 11:19:55 · answer #3 · answered by 1diputs 4 · 1⤊ 0⤋
I had a 70' monte carlo with a 300 hp. 350ci. in it many years ago.I believe it had the "394" heads on it from the factory. Anyway the correct spark plugs for it are AC R44S gapped at .035in. with the stock "point type "ignition system. With electronic ignition go to .045in. Seems to me that a 30 over 283 comes out to a 289ci.
2006-12-30 02:33:23 · answer #4 · answered by racer123 5 · 1⤊ 0⤋
It doesn't sound like there is a problem, but the only way to know is to run it for at least an hour or two to make sure its all worn in, and then see if you continue to have the oil problem, then worry about it, but for now i would say not to worry about it
2006-12-31 04:11:37 · answer #5 · answered by andrew b 2 · 0⤊ 0⤋
You need to use high quality push on style seals like GM used on late generation 2 small-block. these work very well. I have had good luck installing this seal on both in and ex and leaving the O-ring seal off at the top of valve stem.only thing, you might have to machine the guide to accept this seal.
2006-12-30 02:39:58 · answer #6 · answered by deltech 4 · 0⤊ 0⤋
Is your engine a 302?? ..... this is how chevy did it, they took a 283 block and put in a 327 crank. This gave the engine 302 displacement. Now if you have a 327 crank in there then you have a 302. As for the plugs I would go with Camaro plugs, and not NGK, NGK are the worst plugs made, get anything else..... NGK number would be......Spark Plug UR4IX NGK........here is a bosch number....Spark Plug HR9BPX
2006-12-30 02:28:42 · answer #7 · answered by Anonymous · 1⤊ 3⤋
you need to put some miles on, depending on the ring you used they might not be fully seated,thats alot of compression check with your local race shop on that head and piston combo,should be a short reach plug though, heat range will vary with the timing and carb, you got alot af stuff going on at once
2006-12-30 00:53:45 · answer #8 · answered by vincent c 4 · 1⤊ 0⤋
To arrive at your displacement you will need to know the bore and the stroke of the engine...then enter those figures into this formula.....bore X bore X stroke X number of cylinders X .7854 = cubic inches.
2006-12-30 08:24:22 · answer #9 · answered by Anonymous · 0⤊ 1⤋