84transamdude

LOL

It may or may not go away.

My itch is I want to build my own motor. My story is, my first 4,000 dollar motor detnated in this thread here.
https://www.thirdgen.org/forums/tech...hat-did-i.html

My second 3,000 dollar motor is still running but questionable to me for three reasons. 1. Not as much power as first motor even thou I have bigger heads and bigger cam. 2. It smoke's way to much for me. 3. not as loppy as my old motor. You can read obout my 2nd motor here
https://www.thirdgen.org/forums/tech...heck-help.html

My motor now is a 4 bolt main with 383 crank 10.4 compression and set of RHS heads. I have a 2 bolt main that is still standard bore and stock crank I believe. Motor had no machine work dont to it yet. 2nd motor has 220rwhp my goal is to do around 300rwhp maybe a little more and run a lower compression so I can run 87 octane. Is this possible.

Now to sratch that itch, do I use my 2 bolt and start over with the stock crank. Or do i wait till fall and take the motor out I have now and start with that.

Never built I motor but am able to tear stuff apart and put it back together.

Keegan84

iTrader: (1)

You have a 383 at 10.4:1 comp with aftermarket heads and you're only making 220rwhp? Also I did not read your current engine thread but if it is not 100% shot I vote rebuilding that one.

As far as a 2 bolt vs your 4 bolt main it doesn't really matter if you're only aiming for 300hp. It is pretty much personal preference.

84transamdude

There is a few pro and con's doing the 2 bolt vs 4 bolts

2 bolt:
pro can keep current motor in car
con will need to pay for machine work and other parts

4 bolt:
pro shouldnt have any machine work to do plus less parts to buy
con wont have a motor in my car.

If I use the 4 bolt I would like to change the pistons, and cam

InfernalVortex

iTrader: (4)

Dont worry about the number of main bolts unless you're wanting to spin it to 7000 RPMs at 500+ hp. At that point you need fancy pants splayed aftermarket main caps. 2-bolt vs 4-bolt does not matter at the levels you're talking about.

Now your compression test was good because all your pistons measured very close to each other. That means your bottom end, your crank, rods, pistons, rings, etc, are all just fine. No need to change anything about them unless there's a knock. If you really want to be thorough you can do a leakdown test, but I just don't think you've got a ring seal problem, and those are the ones that are a big deal to fix.

You complained about it smoking on startup and deceleration. That's just valve seals. There's a lot of different varieties of them, some guys dont even run them on race-built high performance motors. It shouldn't do that, but they do sometimes. For someone unfamiliar with the process of replacing them and the purpose they serve, it's hard to explain the severity of the problem. Mainly, the problem is mostly just one of appearances. It looks bad, and it sucks up oil (Depending on how bad it is) and you have to top off the oil regularly. But it doesn't really affect the performance/power or even the durability of the engine - your mechanicals can be completely healthy with bad valve seals. Sucks that you have a new engine with crappy valve seals, but in the grand scheme of things it's not a big deal beyond the fact that it's just annoying to change them.

If you want to change it, you'll need to go through a rather tedious process of removing your valve springs and valve train and see what type of valve seals you have, and then you can see what options you have for a better type of valve seals. A lot of old school guys like to use those "umbrella seals" as they call them, and they just aren't very effective. So put new valve seals on your to-do list, but as long as you keep the engine filled up with oil, it's nothing to worry about too much. If you build a new engine, not using those nice RHS heads is just silly, and that's where your oil smoke problem is coming from.

Now we are at the problem of your power output. The thing that determines power is airflow through the engine. We need to know your camshaft specs, your cylinder head part number, your intake/fuel system details, and your exhaust situation.

Ignoring exhaust just because that's chassis specific and we're talking about engines, the power potential of an engine is determined by intake manifold, cylinder heads, and camshaft. Those 3 things need to be matched with your compression ratio. Your compression ratio is 10.4, that's high enough to hit the 400-450hp range with a 383 with good heads. If you have RHS heads theres a good chance you are missing a good 100-150 wheel horsepower.

The other thing you need to check is ignition timing. You know how critical this is to NOT overdo from your first experience, but I think no matter where you set it before, it would have blown up. Your C/R was just way too high. At 10.4:1 now, you're still way too high to run regular gas. Just give up on it. Go get a commuter car for that. If you were 9.5:1 you may have been able to do it, but at 10.4:1 it's just too risky. If all the mechanical and hard parts are in place to make power, and you're not, and the compression test looks good, it's all in the spark curve and the fuel curve.

Get us your cam specs, head part number, and tell us about your fueling system so we can narrow it down.

If you build another motor you're going to be re-using a lot of what you have, as you've got some really nice parts. There's no reason you can't make what you have already work for you.

84transamdude

thanks for the post. Ill try to get that info.

Oh and I'm running 93 octane at the moment.