I have a 79 with a 383 stroker that we built 11 years ago .
it was a kind of high rev engine with big solid roller cam and darts iron 64cc 215 heads (the car was l82 we built the engine on the original block)
last month i broke a piston from detonaition and now it will need a rebuild.
2 things changed with the years ...im less younger , and the original trans with final drive of 1:1 replaced by tko 600...
so now when im less younger and have a wife and over drive i will like to get a smooter engine with power that comes early with better fuel economy , i dont want a dog its still need to be strong...
my engine builder saggest to change the cam to a hydraulic roller from comp cam - 12-466-8
the specs will be
Dart iron heds64 cc 215
Comp cam 12-466 -8 and competible lifters
cr was 10.5 and we want to stay there its near the max you can get without using premium fuels here
rottating assembly stays we will replace the pistons for new ones

The ideal is to rebuild the engine on a tight budget the original engine hed only 15k miles in all most 11 years

Im asking from youre opinion is this cam will do the work?
can you advice for peoper lifters for this cam?

Thanks

 

It would help to know what rear end ratio you have in the car and what type of driving you do, mostly city or highway? I am sure some of the engine builders will chime in regarding the cam and lifters. Lastly, have you opened the engine to determine if it can be rebuilt? Good luck. Jerry

 

I was going to suggest these if your on a budget as I have had great success with mine and my comp retro roller cam but something is up with the price on these as they were only about $20 each when I bought mine 2 years ago and no they are astronomcal at over $200 for each pair? Unless thats now for a set of 8 and the description is wrong.
https://www.rockauto.com/en/parts/en...ve+lifter,5548
EDIT it looks like this is the price for a full set once I google the part number. when I bought them they were individually sold for $23 each.

 

my opinion, I think that cam is good for low/mid power.
BUT
I don’t know your current cam specs, so making some assumptions off your description, I think you are swinging too far to the milder side.

EDIT. I would also do some calculations to determine your new dynamic CR when using that smaller cam. If you are already have detonation problems, a smaller cam will make it worse.

 

i will check if the price for set and its a good products its a great price

 

More details

Im driving mostly on twisty roads/ high ways ...barly get inside towen ...once a year will get to the track...not somthing serius ..but im using the AC allot...its hot in here😃
i have tko 600 with modern tires but atill 27' diamter and 3.36 rear axle

 

Your dart 215cc heads are not a good match for the driving you do or the cam specs you presented. Are new heads an option? You built it originally to be a high reving engine with a large? cam. But now want a smaller cam?
The heads and intake flow will make it more sluggish down low and mid range. With a smaller cam you'll not get to the RPM's needed to make that head work.

 

I agree with going with a roller cam. I have 10.5 compression ratio for the same reason you mentioned. Less detonation, engine run on at shut down.

Are you going with Forged pistons or hypereutectic pistons? Just out of curiosity, was the piston that broke cast, hypereutectic or forged?

 

First off you need to determine what cam spec is your existing solid roller. Then you can make wise decisions on what to buy next. You also need to find out the true compression. Let's say that your BIG solid roller cam was 242/248 108. Toning it down would be dropping like 6 degrees and going with 112 lobe center.

If you actually have 10.5 C/R which is feasible with flat tops and some .040 gasket with 64 cc heads. You would have terrible detonation going to some horribly wimpy cam of only 218 int./224 Ex. Comp cam 12-466 -8. Iron heads will only make it worse. My advice it to go with a cam like. Xtreme Energy 236/242 Hydraulic Roller Cam K-Kit for Chevrolet Small Block - COMP Cams® Only order it as 112 and made out of billet steel with a sleeved on dizzy gear.

The rule is big flowing heads take less cam to make the same amount of horse power.

 

the true compression was 10.5
You seggest a bigger cam then what my builder offer
I dont want rough idle and to get the power very high

The cam i have now is from crower as far as i remember around 250 ...with power band between 3500 to 7000

Only after taking the engine a part we can check exactly the specs ...

You think i will have detonaition problem with the new cam?

 

they were hypereutectic

 

static compression is different than dynamic compression. You need to do some math with cam specs to determine the new DCR with a smaller cam.
as mentioned before, if you are having detonation problems with a bigger cam, going smaller with make it worse. Until the rpm’s get high, a large cam bleeds off cylinder pressure from overlap. Smaller cam, smaller overlap, will have smaller bleedoff therefore higher cylinder pressure

 

Ok i understand now the idea...
The corrent engine didnot had detonaition problem in normal operaition temps...only on very hot days when i got it around 225f it could knock..
the damege heppend when i floored it on high gear in a long climb hill ...i didnt hear it knocks until the damege heppend.
we can lower the CR if needed or i can use higher octan fuel its just much more expensive here

 

You may want to consider forged. But there are people much more knowledgeable about this than me.

 

there are dynamic CR calculators available. Ideal to stay in the 8-8.5:1 range for pump gas. If you do go with a much smaller cam, and you find your DCR too high, easiest(cheapest) way to adjust is a different thickness head gasket. This does affect your quench, but hopefully there’s enough wiggle room where you can find a happy medium with quench and DCR.

as for piston type, I’ve used cast/hyper/forged.
I like hyper for street motors. Good material, strong, but as you found out, has very little tolerance for detonation. Nothing wrong with using hyper again. Plus changing piston type would result in rebalancing the rotating assembly.

I would just carefully review all factors before making a purchase to make sure it’ll work out right. Piston volume, quench, head gasket thickness, new DCR, new CR.

 

With 10.5 just plan on using 93 octane with a cam of 236/242. If your previous cam was 250 @ .050 lift that is a big change and my 383 with the 236 cam had a relatively good 900 rpm idle.

I would not use hyper pistons in any performance build. I had hyper piston failure many years ago and I will never buy them again. You need to address 225 F degrees. It's not good no matter what kind of motor you have.

What country do you live in?

 

Im from Israel...in the summer its can get pretty hot here...
225F its the top it can get with Ac on
Normal working temp are 190~210F

in my situaition it will be a problem to change pistons ,there is no place that can balance a rotating assembly here...

 

My 1979. L-82 came with 3 core thick radiator, a big mechanical fan, and big electric fan that came on with the AC. It had the ability to freeze me in the car when it was new on a typical 44 degree C. day. As time went on and HP went up so did engine temp. I got rid of the mechanical fan and brass radiator in favor of twin Spal brand fans and went to a 1000 hp aluminum radiator. I made the chin spoiler larger to keep air out from under the car.

 

its seems we have the same car ...my car was 79 L82 4spd
i have it from 2009 i replaced the radiator with 4 row aluminum one with duel spals. in summer days thay its was running hot with the AC on 210-220 and 225 for short periods...
i replaced the spals with a big vent from mercedes its now working much cooler but still can get hot on trafic in summer and ac on
i hope with the new engine with much smaller cam its will work less hot

 

I also would install forged pistons made from 4032 material vs 2618. They can be run tighter for better oil control and less noise..yet be a LOT stronger than hyper anything. As GKULL said, I would never run hypers in anything I was going to use hard. We don't have the luxury of infinite tuning like new cars with them...so can't compare. Need to build a good shortblock to handle the HP and the heat and possible detonation which is likely to happen again.

As far as balance, just order pistons that weigh the same as yours. You can juggle it some with heavier/lighter pins also. Ck the specs on them....or just balance them to same weight with a gram scale as what you pull out. No need to re-balance whole engine.

For what you're describing, a 9.5 or so compression ratio with a smaller cam will be best. The big heads will still let it rev out to wherever you want it to go.

I agree when you get in the 10.5+ range..93 octane is needed.

The big heads don't scare me at all....cam'd properly they'll be fine, but being iron make the tune and temp control more important. Shoot for a tight quench area.

If cking valves every year or two isn't a problem, you can stay solid roller and have less worry. Or send your current cam back to MFG and have it reground to a different spec for $150 or so. Very common to do.

On the cam selection...I just want to point out that "overlap" has NO impact on cylinder pressure. It's the most mis-quoted thing on the net concerning cams. It's been said so many times people believe it. Just take a moment and think about where overlap occurs....it's when both valves are open. There is NO compression happening during overlap. The misconception happens because cams with a lot of overlap typically have larger duration numbers which cause the intake to close later. THAT's the key for cylinder pressure. But I can easily have a cam with a lot of overlap but an early closing intake and still have a ton of cylinder pressure. Or one with little overlap and a late closing intake. Lobe design is the key. Now, yes..overlap can impact cylinder filling etc etc...but that's way down the line of the typical discussion and will get into intake and exhaust tract waves etc.

JIM