1. What is the difference between a roller block and a non-roller block?

2. If I don't build my 383 using a roller block, do I just need to change the lifters and that's it?

If so, what kind of lifters should I get?

Thanks!

I hope it's that simple.

 

A roller block has a casting in the lifter valley so you can bolt a "spider" into place. This means you can use normal factory roller lifts, with the spider. ie. a roller cam goes into the engine cheap.

If you use a non roller block you need to use "retrofit" roller lifters. These ones are connected to each other (rather than using a spider) to keep them from rotating. These cost a crapload more than factory lifters. ie $400 or so.

Other then that, it's just that simple.

 

Thanks! I appreciate the response.

 

I had a question regarding that as well. Can you run flat tappet lifters and cam in a roller block?

thanks!

M.

 

why would you want to? Sell the flat tappet and step up to 1980's technology.

 

That doesn't answer the question.

http://www.theturboforums.com/smf/in...?topic=61219.0

This novel of a forum post (103 pages) is the chronicle of a guy taking a stock bottom end truck motor and putting the twin turbos and the bottle to it to see how much power it'd make before he killed it. It refused to die, (probably due to the fact it never went over 6k and he's a really experienced tuner) and before he removed it, he ran a traction limited 9.37 at 150 mph. It was over 700hp and 700 lb ft with torque converter probs when it was on the dyno. On paper, to make his car run 150mph 1/4 was over 900HP.

Anyways it's inspired to see what this thing'll run. It's a stock l05 out of a '89 suburban and I had intended to replace it top to bottom with a 383 anyways so I really don't want to put a lot of $$$ into it. I'll be throwing money at the fuel system instead. It'll never see over 5500 rpm and I can't find a cheap roller cam so I thought hell, do I NEED one?

M.

 

Yes you can defeat the added value of a roller block and waste it, by downgrading to the inferior system. GM themselves did it in their lowest-performance engines built from those blocks, specifically the majority of the TBI trucks, where the advantages and superiority of the roller system (unlike in our applications) was of no particular importance to them.

Why ANYONE interested in building a "better" motor would want to shoot themselves in the foot that way, is however, a complete mystery to me.

Yet another excellent example of how just because a thing is possible, does not automatically translate to it being a good idea.

 

But what does twin turboing a junkyard engine have to do with the possibility of using a flat tappet cam in a roller block? It'll work, but it's not a great idea. Now how did we get on the topic of twin turbos and what HP a block can handle?!?

 

Sorry about the unintentional threadjack.

sofa, call off your dogs

I don't want to "build" this motor AT ALL. I want to throw a cheap cam in it, fresh springs on the the valvetrain, put mpfi on it behind some junkyard turbos and see what will happen. This will be my first boosted application and there's a lot of things I could do wrong that will turn ANY motor into slag. Spending $200 less on an engine I may scatter all over the road because of a tuning error does seem like a pretty good idea to me. I'll spend money on the things that will get transferred to an eventual 383 build, which WILL get a roller cam.

This engine will not be running huge lift or duration, will not be revving over 5500 RPM and may not last a year. Short of a slight mechanical friction difference, I don't see what other benefit I would gain other than the weightloss of the dollars from my wallet. Am I missing something here?

thanks for your answers everyone!

M.

 

Ok, I was lost there. Whole new poster now eh?
Ok, I didn't realize you were going to be "building" an engine with twin turbos. I thought you only wanted to know about the cam idea. Which yea, you can use a flat tappet. But if you have a running roller motor, complete with roller cam, a replacement roller cam is about $250. A flat tappet, with lifters and pushrods comes quite close to that price. You have to swap ALL the parts out, vs just the cam itself. So for the $50 difference i'd stick with roller. But if it's just a roller block with nothing in it, then sure, go with a cheapie flat tappet.
Then again, if you "blow" your motor, typically the cam is still usable. So you may as well only spring for a cam once and re-use it (roller).

 

Putting a flat tappet cam in a roller block is like hiring a hooker to do your taxes....your just wasting everyones time. Less friction alone is worth the cost. Let me get this straight you are goin to spend all the money on turbos (ALOT of $$$$ for quality) and then cheap out with a flat tappet what you dont want at least another 20hp? If theres one thing Ive learned over my misadventures is when you try to do somthing the cheap dumb way then you will end up doing it the good way in the end and spend even more $.

 

And don't forget, you'll get beat a bunch in the meantime, by all the people who already did it right.

 

That's CLASSIC! That's a keeper right there.

 

The embarrassing thing about all of this is my original one sentence question was theoretical as I'm not even sure I have a roller block anyways. It's an L05 truck motor so it may well already be flat tappet. Is there a way to identify via casting numbers or external cues?

Awilson, will I really lose 20 hp if I'm never revving it past 5500? I thought most of the friction based losses were due to RPM. How did you come up with that number?

Sonix thanks for the reply... If it is a roller block I will definitely consider doing a roller cam, but as the future 383 will be built with a real set of heads and likely a 6500 rpm redline, it'll flow way better and need more cam anyways. A Summit brand cam and lifter set is 89 bucks and the guy in the link I posted pulled something like 600 hp out of one of those pieces of crap. I will buck up for decent injectors, a bombproof ignition and a fuel pump that'd drain a swimming pool in 15 minutes and all of those items are transferable to a bucks up engine.

And, once again, THIS IS NOT AN ENGINE BUILD. It's a disposable engine. It's an otherwise stock 350 Chevy truck engine. I know it's a piece of crap. It'll get head gaskets, a cam, a better oil pump and valvesprings and not much else. I'll be buying junkyard turbos or maybe even really gamble and order a crappy ebay kit. I know it ain't "right" but it'll be cheap and I won't cry too hard if something goes wrong.

See, my initial plan was to build a 383 with forged crank and pistons and h-beam rods and then I started thinking of how bad it'd hurt while learning how to tune a turbocharged engine to accidentally turn it into shrapnel. Plus I'm friggin' broke-*** poor. I'd be saving for three years to build the 383 I want. I figure I can put a pair of crap turbos on the car for about the same cost as just the blingy Eagle bottom end kit I was drooling over at Summit.

I sincerely suggest reading the link I posted, despite its length. It's a great example of thinking outside the box and although I don't think I'll be able to make mine run as hard as the one he built, I'd like to try the same formula. He ran a 9.35 at 150 mph on a rebuilt, cast piston, cast crank, .040 over 350 with a sleeve in one cylinder and a 150k miles on it. Hell, he got it into the nines with a set of heads with 1.74 intake valves! If my results are a fraction what his were I'll not bitch about it. It'll be a learning experience and I think I'll have some fun along the way.

Thanks!

M.

 

Friction happens everywhere in the RPM range and a roller will provide less friction throughout the entire range. Friction=bad and less friction=more Hp as far as the number from an average of who Ive talked to and in my own experience Ive found a roller cam over a flat tappet is worth right around 20hp I built a couple 355s in the last few years and the last one was a retrofit roller and the profile on the cam was almost exactly the same as the one before it and the rest of the motor was 99% the same and I ended up with like 18.5 more hp about everywhere in the RPM range other than very low revs. Ive talked with alot of people about roller cams and from what Ive heard 20hp is average. But the hp isnt the biggest advantage the durability is. How many sbcs have you pulled the cam out of and seen a flat lobe?? Ive seen more than I can count. A roller eliminates that for the most part until it has mileage so high somthing else breaks. I understand money issues but its not that much more and if you want a mule to experiment turbos on you might as well have a durable mule. If you flatten a lobe breaking the cam in (ive seen it happen) do you really want to pull all of the turbo plumbing and what not off so you can yank the motor to replace the cam? I wouldnt lol. Spend a little now...save alot later.

 

The reliability issue is a good point. I've heard it's more likely to flatten exhaust lobes on a turbo due to the higher cylinder pressures generated.

I still don't really know if it's a roller block or not though... know any way short of popping the intake off to tell?

Thanks!

Mark

 

get the numbers on the block and pull up one of the millions of websites that have chevy casting #s listed and it may tell you.

 

finally crawled under there and determined what block I have, but it's apparently a really general casting.

From mortec-

14093638...350...87-95...2 or 4...Roller or flat tappet cam, one-piece rear seal

Bugger. Anyone have any slick ideas to determine roller block status?


thanks,

M.

 

Well, I popped a valve cover off and shot a coupla pics of the tops of the lifters through the heads...







I'm pretty sure those are flat tappet, correct? The pictures I found online of a hydraulic roller setup seem to show a retainer that'd sit on top of the lifter bores.

thanks for your patience all.

M.

 

Yes, those pics would lead me to believe that it is a flat tappet cam (doesn't look like it has dog bones). I think you can also determine by pushrod length. You're only one nut away from yankin one and measuring.

More on roller cams. What most don't think about when discussing roller cams, is the added HP numbers they get not only from less friction, but also from the (typically) more aggressive lobe (ramp). B/c there is much less friction the cam designer/engineer can open and close the valve at a much faster rate than a conventional flat tappet w/o having to worry as much about longevity.
----------
wow, sorry, this thread is kinda old.

 

that block is a roller block however it is presently equiped with a flat tappet cam... as most of the truck blocks are... notice the milled surface around the lifter bores... that is done to support the dogbones