stroked340
Well-Known Member
Your absolutely right my 416 was basically built with parts right from Summit except for the heads
416" small block cam
- Thread starter ncDemon
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Your absolutely right my 416 was basically built with parts right from Summit except for the heads
moper
Well-Known Member
There's "need to", and "should". While one doesn't "need to" bush the block in some cases, there are reasons to do so that make it worth while. You drop in your lifters. I'll build an engine...lol.
ncDemon - the solid flat tappet is lighter, doesn't compress, and can make more power overall and less peaky power curves than a hydraulic flat or roller for a lot less $$. Unless there's a reason to avoid checking valve lash twice a year it's foolish not to run solids. A modern flat tappet will need less spring, and make more power than a hydraulic roller, without the $500 plus in initial cost. But you have to be good enough to safely break it in, and you have to be saavy enough to buy the right oil for your application - even as the oils change over time.
Solid rollers are the ticket to big power - but again - at your builder's discretion - there should be more to it than "dropping in" the cam and lifters.
Will do! I'm not going to argue that bushing the bores isn't better than a drop in because yes, there are benefits to it and I understand the reasons to do it. I was just stating to the OP that he doesn't HAVE to bush the bores with today's lifters. That's all.
I was in no way disparaging using off the shelf components. As an infrequent engine builder I tend to use exactly that- nothing custom made, ground etc. I was referring more to using an engine recipe- i.e. Joe Bob used these components and made X hp- if I do the same I will make the same hp. We all know that is not necessarily true.
While everyone has been very helpful I'm still frustrated by this whole thing. Navigating the decision tree on this issue is very complex.
Moper- Are we talking about running oil additive for the life of the engine with the solid flat tappet? I'm really starting to lean this direction- and you have made some excellent points supporting it as well. I really don't want to truck the block back to the machine shop and bush the lifter bores. For a street car is there a good reason to do this rather than just doing the oiling mods on the block to restrict oil to the lifter bores?
Edit to add: does anyone have specific cam/lifter/rocker recommendations for a solid flat tappet?
While everyone has been very helpful I'm still frustrated by this whole thing. Navigating the decision tree on this issue is very complex.
Moper- Are we talking about running oil additive for the life of the engine with the solid flat tappet? I'm really starting to lean this direction- and you have made some excellent points supporting it as well. I really don't want to truck the block back to the machine shop and bush the lifter bores. For a street car is there a good reason to do this rather than just doing the oiling mods on the block to restrict oil to the lifter bores?
Edit to add: does anyone have specific cam/lifter/rocker recommendations for a solid flat tappet?
moper
Well-Known Member
I'm not a fan of additives - I mean run the oil you need. One of the things my old instructor used to say is the best case when oils are combined is the lowest level of protection of the weakest portion and I still just don't feel additives are the answer. These are specialty cars and don't rack up the miles like they used to. Most guys will have no trouble dropping $70 on race fuel for a track day, but for some reason balk at spending $70 for oil three times a season. Brad Penn, Joe Gibbs, full synthetics, whatever you need is fine. The break in is critical - and the break in includes the very first fire up and any turning over before that firing. You just can't do it like we used to when you run an aggressive, modern flat tappet.
As for bushing the bores I do it for several reasons:
Oil control - Not just controling the leakage at max lift in those blocks that have the spot facing and height issue, which is what the full body lifters do, but also controlling all lifter leakage in any scenario including in the case of valvetrain failure where the lifter can kick out of the bore, dumping all oil pressure to the lower end. You cannot shut it down fast enough to prevent the lower end from getting destroyed if you lose something on the right side of the engine at speed. Tubing can also do that for less money, but tubing doesn't do anything else for you which leads me to...
Lifter position correction - The factory couldn't get the decks, main bores, or cylinder bores mahined in the right spots. What makes anyone think the lifter bores are any better? The angle they're drilled on and the position in relation to the lobe can be off - a lot. If you've read about Hughes having issues when they first started out it wasn't the cams, but the fact that the cams depended too much on the factory angles being "just right" between the lobe and lifter face and they're not. I tend to use .875 lifter profiles for my custom cams with very aggressive rates of lift for that reason. Bushing using a modern CNC mill can address that very effectively. This will help valvetrain stability which translates into more power, and more usable rpm. It also means longer lifter life between rebuilds which can be an issue for street cars with bigger spring pressures. Tubing doesn't help that. Drop in lifters don't help that.
Bushing costs $500 during the block machining. A roller cam small block will have a budget of $10K give or take, more for a big horsepower stroker with some real heads from a competent shop. Are the benefits worth 5% or less of the total budget? Only you and your builder can say. I can make the same power as any hydraulic roller tappet engine with flat tappets. Anyone that says they're worth any power over a solid flat tappet is full of crap. The ONLY good things about them is you can run the cheapest oil and really ignore having the engine's first start go right. I built an engine running stand to be able to properly manage that part but I understand that others don't have that sort of stuff. It's all relative to an individual's situation.
As for bushing the bores I do it for several reasons:
Oil control - Not just controling the leakage at max lift in those blocks that have the spot facing and height issue, which is what the full body lifters do, but also controlling all lifter leakage in any scenario including in the case of valvetrain failure where the lifter can kick out of the bore, dumping all oil pressure to the lower end. You cannot shut it down fast enough to prevent the lower end from getting destroyed if you lose something on the right side of the engine at speed. Tubing can also do that for less money, but tubing doesn't do anything else for you which leads me to...
Lifter position correction - The factory couldn't get the decks, main bores, or cylinder bores mahined in the right spots. What makes anyone think the lifter bores are any better? The angle they're drilled on and the position in relation to the lobe can be off - a lot. If you've read about Hughes having issues when they first started out it wasn't the cams, but the fact that the cams depended too much on the factory angles being "just right" between the lobe and lifter face and they're not. I tend to use .875 lifter profiles for my custom cams with very aggressive rates of lift for that reason. Bushing using a modern CNC mill can address that very effectively. This will help valvetrain stability which translates into more power, and more usable rpm. It also means longer lifter life between rebuilds which can be an issue for street cars with bigger spring pressures. Tubing doesn't help that. Drop in lifters don't help that.
Bushing costs $500 during the block machining. A roller cam small block will have a budget of $10K give or take, more for a big horsepower stroker with some real heads from a competent shop. Are the benefits worth 5% or less of the total budget? Only you and your builder can say. I can make the same power as any hydraulic roller tappet engine with flat tappets. Anyone that says they're worth any power over a solid flat tappet is full of crap. The ONLY good things about them is you can run the cheapest oil and really ignore having the engine's first start go right. I built an engine running stand to be able to properly manage that part but I understand that others don't have that sort of stuff. It's all relative to an individual's situation.
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