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Old 03-11-2009, 01:36 PM
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Can roller lifters be used with a flat tappet cam?

I am just wondering. After my latest build, I'm thinking about building a 350 roller vortec block and was wonderign if there are any special requirements for cams in roller blocks

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Old 03-11-2009, 01:50 PM
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The lobes on a flat tappet cam are ground on an angle as you're holding the cam out in front of you from left to right (looking at it from the side of the cam). One side of the lobe is taller from the centerline of the cam core to the tip of the lobe. This is what allows the lobe to turn the lifter in its lifter bore as the lifter is lifted.

Roller cam lobes are cut straight across to mate with the flat, straight across roller wheel on the roller lifter because the roller lifter doesn't turn in its bore.

So, can you use a flat tappet cam with a roller lifter? No.
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Old 03-11-2009, 01:50 PM
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Seems to me you've asked 2 questions.
1. can roller lifters be used on a flat tappet cam.....NO
2. are any special requirements for cams in roller blocks.....
Not sure, but I don't think so.
JA
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Old 03-11-2009, 01:53 PM
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A roller block with one piece seal is the only block I would consider building anymore. You can use an aftermarket roller cam with the GM roller lifters, dog bones and spider if you want. Just don't use valve lift of more than about 0.525" or a little more (measured with 1.5 rockers) or you'll pop the lifter out of its bore and things will go downhill from there.
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Old 03-11-2009, 02:53 PM
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Quote:
Originally Posted by maxpower_454
I am just wondering. After my latest build, I'm thinking about building a 350 roller vortec block and was wonderign if there are any special requirements for cams in roller blocks
1. To the first can roller lifters be used with a flat tappet cam, well yes but you'll be seriously disappointed with the result in terms of wear and power.

- In terms of wear, flat tappet cams have a side to side slope intended to rotate the FT lifter. This will cause a roller lifter to run on one edge of the roller which will fail the cam and the lifter's roller in pretty short order.

- In terms of engine power such a combination will loose huge amounts of power because of fundamental design differences between flat and roller tappet cams. A flat tappet presents a linear surface to the cam lobe, going over the top of the lobe, the lobe sweeps across this distance and is seen as duration at the valve. A roller lifter makes instant contact with the lobe, so going over the top of the lobe there is no side to side travel across the bottom of the lifter as with a flat tappet. Since this is a huge part of the duration seen at the valve, this sweep time has to be built into the shape of the lobe. This makes roller cams look more aggressive than their flat tappet counterparts even though any two of these type cams could have identical timing events at the valve.


2. To the second question, Vortec blocks and several others in the period of 1986 to end of Gen I production have the provisions for roller cams, even though the may have been built by the OEM with a flat tappet cam. But there were truck blocks built till mid 1995 that are flat tappet blocks which like all pre 1986 blocks have no provisions for a roller cam. The casting numbers are thus:

- For 350 flat tappet blocks look for casting number 10054727, 14079287, 14088548, and 14101148.

- For 350 roller tappet blocks look for casting numbers 10243880, 14011148, 14088526, and 14093638.

- A problem you could encounter is that there is a flat tappet block and a roller block that both end with the numbers 148. 14101148 is a flat tappet truck block, 14011148 is a roller provisioned block.

Bogie

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Old 03-11-2009, 03:40 PM
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Thanks! That helps a lot
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Old 03-11-2009, 09:06 PM
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i actually just grabbed an 880 engine today. Complete long block...

I stumbled across this thread when i was reading about if i wanted to keep it or not...

************ I am debating on using the heads, the whole long block or nothing at all .....

Last edited by powerrodsmike; 03-12-2009 at 09:37 AM. Reason: Classified ad. Please use the Hotrodders Classifieds for classified ads.
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Old 03-11-2009, 10:53 PM
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Hate to change the nature of this post, btu while we are on the subject of newer 1 piece blocks, a lot of buildiers in my area actually still prefer the older 2 piece blocks. I asked why and they say the material is better. I have been debating this for several months now and have not built anything as a result. I have an early block, but did want the features of a roller block. I was told I can use linkbar lifters, a cam button, and a roller cam to convert my non roller over. What are some of your opinions of the newer 1 piece blocks vs the early blocks. I have no problem doing either.. but when several engine builders tell me the early blocks are better, kind of makes you wonder.
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Old 03-11-2009, 11:27 PM
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Carlos9, I've heard the exact opposite, that the older blocks are of poorer quality metal and are more likely to suffer from core shift. I tend to believe this as Vortec heads are better than previous models, and casting quality is higher on virtually any casting industry-wide. The newer casting also accepts a 3.875"( makes a 396 cube out of a 350) stroke crank with less chance of hitting water than an earlier casting. Some older guys just don't like the thought of anything non-traditional and therefore brand them as inferior.
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Old 03-12-2009, 05:53 AM
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Quote:
Originally Posted by ericnova72
Some older guys just don't like the thought of anything non-traditional and therefore brand them as inferior.
Don't know who you've been talking to, but this "older guy" will say this:

Dollar for dollar, you cannot beat the OEM roller blocks for street performance/mild race-type apps. The blocks are lighter, but with CAD/CAM I believe that nothing significant was sacrificed in the way of strength and durability.

For myself, nickel content of the cast iron alloy just isn't a priority.
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Old 03-12-2009, 09:41 AM
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Nelson67Camino-
Your post #7 in this thread seemed to be a mix of a question about the suitability of your new found part and advertising.
If you'd like to let folks know you have something for sale, and want to test the market, use our classified ads.

The link to our guidelines are at the bottom of every page here, and the rules are clearly defined.

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Old 03-12-2009, 11:04 AM
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Quote:
Originally Posted by Carlos9
Hate to change the nature of this post, btu while we are on the subject of newer 1 piece blocks, a lot of buildiers in my area actually still prefer the older 2 piece blocks. I asked why and they say the material is better. I have been debating this for several months now and have not built anything as a result. I have an early block, but did want the features of a roller block. I was told I can use linkbar lifters, a cam button, and a roller cam to convert my non roller over. What are some of your opinions of the newer 1 piece blocks vs the early blocks. I have no problem doing either.. but when several engine builders tell me the early blocks are better, kind of makes you wonder.
Most older blocks are simple gray iron. Where additional strength was required nickel was added such as with the 4 inch bore 010 block commonly found from 302 Camaros to 350 3/4 ton trucks. Core shift was managed with thick castings.

When thin wall was introduced during the early 1970s over-boring became a problem as there wasn't as much material to start with so going an 1/8th inch was totally out and with core shift an ever present problem going to .060 could be iffy, especially with non heavy duty blocks.

Newer engines are, or have, moved to the elimination of nickel alloys for strength and instigated the use of Compacted Graphite Iron (CGI). This stuff is nearly as strong as nickel alloy iron at substantially less cost. It's tough to machine compared to gray iron or even nickel iron, but modern cutting fluids, ultra high tool speeds, and diamond tool facings have largely overcome tool life issues.

As for two piece seal blocks, they are way more temperamental to seal up than one piece blocks. But if your careful, they can be made oil tight. I think a lot of builders prefer the larger diameter bolt circle of the two piece crank from a strength stand point. But the one piece design puts a wider piece of metal on the end of the crank so it appears the smaller bolt circle will carry the same loads. There's also the issue of counter weight with racers, the one piece seal uses a counter weighted flywheel or flexplate, lots of builders prefer a balanced shaft with a neutral balanced fly/flex. So this requires an extra effort at balancing the shaft in order to simplify field changes of the flywheel or flexplate.

As for using using link bar rollers in pre OEM roller blocks while it's done a lot, it has two big problems. The first is cost, aftermarket link bar rollers are a lot more expensive than the OEM system. The second issue is setting up the clearance on the obligatory cam bumper with a roller cam in a non roller block. This is a tedious process at best and often requires a different and stronger timing case cover so it doesn't deflect when loaded by the bumper and or a different aftermarket water pump that includes a boss on the bottom that installs a bolt that is used to pre-tension the timing case cover so it, again, doesn't deflect under cam bumper loads.

Bogie
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Old 03-12-2009, 05:06 PM
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I've never heard of any issues with the latter part of your comment about non oem roller blocks. Thanks for the lenghty explaination. You left out one thing though.. and that is which block you prefer. From your explaination, it sounds like the late block is just as strong as the early.. although lighter. I don't have a problem going linkbar system, but I am unaware of any issues you mentioned with timing cover and or other parts involved.

As far as the weights or balancing goes.. you are right in that most want an internal balanced engine rather than external. I just know a lot of guys that WON'T have the late blocks. This is why I jumped in and asked. Maybe some of the challenges with machining them is the reason why..

Personally I am and have been stumped on which block to build for a while now.. and therefore, nothing has been built. I have an early block that's ready for pistons, and a late block that I still need to purchase ($150) + machine work before I can get it to the point where the other block is. I can sell my early block to a performance shop that buys them for $150 to pay for my late block, but I am still stuck with a crank/rods (that I paid $100 for) and cam bearing ($40 installed) that I will probably have to eat. I would be out a total of $220 starting over with newer block. That is:

$100 Crank and rods
$ 40 Cam bearings
$ 80 Bore and hone

Sorry to hijack this thread, but it was sort of in line with what I am doing right now. Can you further explain the issues with timing cover etc. going the retro roller route. I may be wrong, but I think I may be money ahead staying on the path I am on. Really money ahead staying flat tappet with the block I have.
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Old 03-12-2009, 05:52 PM
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What muddies the view here, is that you already have a 2-pc. rear seal block basically ready to go. Obviously, you will have to decide which you prefer to build, but I wouldn't be scared away from a 1-pc. rear seal roller block because of the weight/material. And you could always sell that block, should you want to build the roller block.

The roller blocks do have lift limits when using all-OEM parts, about .550 lift, IIRC. And the stock roller lifters are rather heavy, though this can be dealt with by using the right valve springs.

If you had no block, the choice would (for me) be easy- 1-pc. roller over 2-pc. flat tappet. All day.

The caution with cam walk applicable to the 2-pc. rear seal block retrofitted w/roller cam/lifters is negated w/the roller block- they use a retainer that holds the cam in position.
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Old 03-12-2009, 06:03 PM
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Thanks and again sorry to hijack original poster. So cam walk is what he was referring to. Does the cam button not work well? I did hear it cost more to balance the 1 piece motors. Not sure why though because you are using the same parts (pistons, rods, crank, flywheel, and dampner).

Yeah, I hear ya on the block I already have. I consider the guy I deal with to be credible.. so I jumped all over the supposedly highly desireable 010/020 cast block. There were 2 other guys that wanted it, but I told my machinist I saw it first. He had been doing block so long, I had to tell him what it was. He did remember somehing about it after the fact.

I am in a pickle.. if money weren't an object, I'd just fold and go roller block. I am not trying to race or anytihng. I just want a good strong/reliable motor for my C10 with a mild RV cam. I have a set of Edelbrock RPM heads.

The late block was not roller, but has the bosses for it. I went to wrecking yard to get spider arms, dog bones, and pushrods if I did decide to get the late block. Question. Does the same dampner that work with roller cam.
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