I've noticed some guys here on the HAMB have been talking about the 348 Chevy engine. Currently I'm rebuilding a 348 for Hotrod 29 here on the HAMB. I figured this would be a perfect time to show a total rebuild to help some guys out that maybe unsure of these engines. The pics were taken after the engine was tore down. I will post pics as I go, but right now the block and heads are at the machine shop, so it will a little bit until I get it back.
You can see that the block is mix of BB and SB. The mains look similar to the early BB's but they use a different main bearing. Rod bearings are BB so that saves some cash because the mains aren't cheap. You can see also that the deck is not at a 90 to the bores like most engines. The combustion chamber is located in the block itself, not in the head like a SB,BB design. Overall these engines are pretty basic, nothing too scary. Plans for this block is a .030 over bore and a .010 turn on the crank, which is forged.
The pistons have a unique shape to them as well. The one half matches the angle of the deck while the other side is angled for the combustion chamber. They are heavy as shit, no wonder these things have a hard time turning rpms. If you look at the head you can see there is no chamber just the valves.
Mikey, A 348 followed me home the other day, I have a 283 powered 58 Chebby that will welcome a W-motor. Thanks for doing this, I will follow along...
Larry I think I can mate two of those 2300 together in a V shape, what do you think? A heads up on these engines. When you are running a stock cast 9.5 to 1 piston, you are limited on cam choices. You will run into piston to valve problems with cams over .460 lift. Something to keep in mind.
Bolt in = GOOD ! After three years of building the model A hot rod, (still not done) bolt in sounds kinda good ! Yeah, it will be cool to stir around in a 4 speed, just like Bolander (and Toad)
I have a 348 tri power in my 28 sedan. I love it it sounds awesome and is definatly cool. Oh and and it pulls nice and hard with about 320 hp. And its not a small block. These w engines have lots of potential for power and lots of torque. There is a 348/409 site on the net www.348-409.com tons of info and conections for parts. John
I was a little concerned about valve/piston clearance with 9.5 to 1 pistons (which is what I'm using in mine) and e-mailed Curt at CH Enterprises about the issue and this is his reply: The 348 350hp cam only had a lift of just over .400 and the problem is not with lift--at full lift the piston is near the bottom of its travel--but with duration and when the valve starts to open and when it closes. The piston is closest at low lift within 10 degrees of top dead center. The more duration--and cams with a lot of duration usually have more lift and that is what confuses people--the more problems and the closer the lobe separation the more problem. A cam with 270 duration @.050 and lobe centers of 106 with 500 lift would be worse than a cam with 220 duration and 114 lobe centers with .750 lift.The 9.5 piston has no intake valve clearance at about 225 duration and 110 centers. we normally use about [email protected] on 110 which is a cam of near .500. The Isky 270 hydraulic would be about as big as you can go. The most populalr is the 262 hydraulic with .488 lift--no problems Curt
There is not a exact answer to which cam will fit. There are alot of factors like: lift, duration, lsa, which will affect this valve to piston clearance. You must also take into account things like: If the block is decked, head milled, oversize valves, and head gasket thickness. When I said that over .460 lift you may have problems, it was taking all these factors into account. You can have more lift and duration but you will have to check the clearances. By the way, Mike, I was at the machine shop on Wednesday, your block and heads were cleaned and stripped, looked like new.
I'm curious as to why you wouldn't want to flycut the pistons, Ross pistons come with the valve relief cut in them.
We are talking about what cam will fit with the stock type piston. If you would read the post, you would see that. Give it a rest, ok. I'm trying to have a post that helps people out, not argue on how to put this engine together.
I usually like to know all of the options when I put an engine together. Anyway, you've got it, I'm done. Larry T BTW, here's the last w engine I put together for a customer.
I agree with Mikey. I'm digging on this post because I just aquired a 348 that I'm sure I will break and it will be nice to know how to rebuild it witha minimal amount of wear and tear on myself and my wallet. I'm a bit tired of seeing people trying to share what they know just to have the thread turned into a pissing match as to who knows what. Feel free to start another thread about fly cutting pistons and what cam will fit what and let Motor Mikey get on with what he is trying to say. Let the rest of us decide if his information is the right fit for ourselves or not. Thanks, RASHY
yeah larry, there are alot of options when you sart spending serious money, but mikey isnt putting ross pistons, or fly cutting my pistons...you can also stroke the motor and make it 400+ cubes, but thats not what were talking about here, were talking a decent h.p. motor on a budget.
Nobodys stepping on my toes. I just wanted to keep it simple for everyone. That way maybe someone who was a little scared to try a rebuild, will have some confidence in trying to put one of these engines together. No hard feelings.
it would be cool to see this thread as a "tech" thread and added to the archives. the chance of it getting there is unlikely if it becomes a battle. we all know there is more than one way to do anything. I would like to see this one. please continue