Steven6282

The gap is just their dyno equipment losing signal for a second. They did two pulls the second pull was a couple hp lower.

My total timing is 32 degrees at 4200 rpm.

As far as it being to lean.... maybe so I'm not going to claim to be an expert or anything. But I don't think .25 to .5 leanness is going to make that big of a difference in my hp. The engine builders didn't think it was a problem even when it was running at 14+ on the first dyno.

I might not be an expert but I can look up numbers. According to other sources I read, naturally aspirated engines perform best from 12.5 to 13.3. So for most of that dyno I'm just over the high side of that. I also found something saying that anything under 14.7 is considered rich... I don't know how true that is I was assuming that red line was lean above rich below, but it looks like that red line is actually just the middle of the optimal range at 13.

I could spend more hours trying to get it .2 to .4 richer and seeing maybe another 5 or 10 hp if I'm lucky (wouldn't count on it since I only saw 4 hp increase with a new bigger intake and .5 to .75 AFR drop). But I'm not going to bother doing anything else to it until the people who built the engine look at it.

Also just a note to 87350Iroc, I find it difficult to believe that nothing but the alternator and water pump would cause a 10% hp loss. The AC belt and power steering pump belt were both disconnected for this dyno. Everything I have read about them say they might cost 5 hp each.

InfernalVortex

iTrader: (4)

You want it to run into the rich side of things under load to prevent detonation. Detonation blows things up.





Never run things lean under load if you can help it. The dyno operators dont have to pay the bill when you blow a hole in a piston. Nor are they concerned as much with getting every last drop of power out of it as you are.

Steven6282

I'm not going off what the dyno operators think

They are the ones that told me it wasn't to bad where it was but I still got it up a little anyway before the last dyno.

If they tell me wrong and it causes damage to the pistons then they will replace them under warranty.

But again, if .5 to .75 change only made a 4 hp difference (if it even contributed to the hp difference, assuming going to a bigger intake made 0 more hp), then I don't think .2 to .4 is going to make any bigger of a difference.

Also like I said, it's just barely outside the optimal range sometimes, sometimes it's inside the optimal range. I don't think barely outside the optimal range is going to be cause detonation. But I'll see what the engine builders say when I take it to them tomorrow.

87350IROC

iTrader: (2)

Are you sure? These are the same guys that installed different smogger head castings on the same engine.

You are getting good advice here. Remember nobody here has a dog in the fight and we help people on our own time. There is no reason for anyone here to give bad advice. I would richen it up a bit if I were you.

Screamin86

iTrader: (1)

i agree with everyone else you deff need to get it a bit richer and get your all in at a lower rpm imo. i usualy like mine all in between 3000-3500 34-35deg would prob work well for that motor like stated. i know exacly what cam you are running i ran it in a 305 years ago when i had no clue what i was doing and i was trying to run all the lg4 stuff (manifolds carb intake ecm dizzy) it nnever ran right and was a slug at low speeds. i later threw on a rpm intake summit 1103 cam correct mech/vac dizzy and some longtube headers and i tell you what i would have taken that 305 up against most 350s any day. its all about parts matching and a GOOD tune.

Steven6282

As I keep saying, we'll see what happens now that they have the car, what they do. If they stand behind the engine and fix the problems then all will be fine and I'll post what the problems where and what they changed to fix it. If they don't want to stand behind the engine, or show me what is wrong outside the engine to be causing it to produce such lower than expected horsepower, then I wont be worried about the warranty or their knowledge much because I will be fighting them for a refund.

I appreciate the information everyone gives me, I just get tired of being nagged about something that has already shown to not make much of a difference. If getting the AFR number up from 14 to ~13.25ish on average didn't make more than a 4 hp difference (again assuming 0 hp gain from the new intake) then what is there to make me believe that another .2 to .4 gain is going to make any better difference?

Again I appreciate the information, but I don't need to be told repeatedly that it needs to run richer when that isn't the big ticket problem here. I'll get that fixed when I work on all the fine tuning, right now I'm looking for the big ticket item that is causing me to be missing 50 to 70 hp, not 3 or 4 hp.

Also as for the heads, I asked the engine builders about it when I dropped it off today. They said that they machine and port the heads to make them higher performance than they originally were based purely on the casting numbers. I don't really know how much you can change a head when machining and porting it, just relaying what they told me.

87350IROC

iTrader: (2)

Yup, its clear you know more about tuning an engine than all of us here. Makes you wonder why you asked for help in the first place.

As stated before, you aren't missing 50-70hp. You are missing 20hp max.

A 340hp crate engine is tested with big dyno headers and oversized intakes. They are tested without any accessories, not even a water pump. So by the time you bolt on your accessories you've lost 10% power. Now your 340hp engine is really 305hp. Now you dyno'd your car on a chassis dyno. Your tires, differential, trans, all take power to turn, about another 15%. So now your 305hp engine is really 260hp. So you are "missing" 20hp max. Figure you are using inferior intake and exhaust to what the dyno uses, plus the mismatched heads, and there is your 20hp. Its a game that all engine builders play. Live and learn.

Regarding the heads, they probably shave them before installation. I HIGHLY doubt they are doing any porting or valve work for that price. They are junk heads.

I like Pablo's saying.

"but what do I know.. I don't know nutting"

Steven6282

Nope I don't know more than everyone here, I'm just basing it on the experience I've accrued directly in the past couple of weeks messing with it. You have yet to tell me how if a .75 shift in AFR can only make a 4 hp difference (once again assuming the new intake made 0 hp difference which I highly doubt), how is a .2 to .4 AFR shift going to make any better difference?

Also as I have already stated the assumption people are making of the 340 hp being on big dyno heads is incorrect. I questioned cmengines about it directly and they said the dyno numbers are based similar specced engines including similar heads exhaust and necessary accessories (meaning water pump and alternator). Now could they have been lying to me, sure. Do I think they where? Not yet. I'm an optimist and generally give people the credit of being honest until they give me reason not to.

I also can say from experience in the past few weeks that the accessories aren't costing me anywhere near the 34 hp you are suggesting. I did a dyno run the very first time with the ac belt and power steering pump connected. The result was 230 hp. Took the ac belt and power steering pump off, the result 234 hp. So being pessimistic, say each accessory is costing 4 hp, that is 16 hp, not 34 hp. That is assuming the water pump and alternator aren't costing more than twice as much hp as the power steering pump and ac, which I doubt they are especially considering that I have a low drag aluminum water pump on there.

So given those numbers and assuming 15% on the drivetrain loss (I've been told by others 10 to 12% is more likely for a manual, but again I'm being pessimistic here) that is 275hp. If they lied to me and their dyno comparisons weren't done with necessary accessories. That is still almost 40hp missing. If they told me the truth about the accessories then it's more like 55hp missing. It's all based on what they told me and even if they lied about it, it doesn't matter because that is what they told me so that is what they have to honor.

Now I'm sorry if you don't agree. I ask for help on stuff that I don't know, generally on here that results in 20 different answers and then I have to start guessing based on those answers. As I guess and learn more I start basing stuff off the actual changes I see. If my changes are unique and not the norm then maybe I'll learn that one day, but there are to many varying opinions being told to me by a lot of different people for me to be able to base on anything except what I've directly experienced.

jmd

iTrader: (4)

I was thinking the same.

Fair enough. But instead of believing CM or anyone in this thread, look at the baseline of an LT1 which is in ways, comparable to your engine. Same bore and stroke. Same basic head design. Same valvetrain design. There's nothing mysterious to it. And if you dig around, enough people have had theirs dyno tested for reference.

It's 275 or 300, stock. Now look at my above quoted post. The parts of your engine that have the potential to significantly change power aren't up to par with an LT1. So you're going to make less power. Period. Your exhaust isn't the issue. You're not missing 20hp from the intake manifold as you found out from your swap from your RPM manifold. Your heads and cam and to a lesser extent compression ratio, are not those of a 340hp engine.

You shopped for price and trusted their number and you bought based upon that number. Now you're willing to "figure it out" with an intake manifold but not heads and cam (which is understandable due to cost and complexity) which simply isn't going to put you at that number as it's mis-matched parts at this point.

I'd more heavily research whether those heads are really a matched pair (I don't care to research parts I'll never use)

You paid a fair price for the engine that it is. Now you're going to get hemmed and hawed by them about the power varying depending on the vehicle in which it's installed and blah blah blah. They'll wear you down, then you'll start planning heads and cam and you'll be where you want to be. Simple as that.

InfernalVortex

iTrader: (4)

I agree.... for the price, even with mismatched heads, it really isnt bad at all.

Swap the heads and cam for something better and you'll be really happy with it after that.

Steven6282

I may end up doing that if I don't get anywhere with the engine builders. I just have to figure out what I can swap to. If I swapped the heads and cam, would I be able to use all my current rotating assembly stuff (pistons, rods, rockers, valve springs)? What is involved in going to a roller cam instead of the flat tappet that I have now? Can I put vortec heads on there (I know I'd have to change my intake if I did that but it seems most people think the vortec heads are good heads)?

Really I think it's to soon to ask those questions until I see what the engine builders say / do, but I guess it doesn't hurt to start figuring it out just in case.

InfernalVortex

iTrader: (4)

Vortecs are great, but they're not as good of a deal as you might think. you'll have to work around their valve lift limitations and get a special intake for them. You already just bought a Performer RPM that will not work with vortec heads, so I'd probably rule them out.

But if you're starting from scratch, Vortecs are great. They're by far the best factory head available.

I would consider getting some Jegs brand aluminum heads. They're made by ProFiler and are amazing castings. Will vastly outperform Vortecs. If you cant afford that, I would go with some 083 or 113(ZZ4 and Vette L98) heads. They have the same ports and airflow characteristics, but the 113's are aluminum. They're not great, but they're servicable if you're on a budget.

As far as flat tappet to roller cams go, you'll have to tell us whether or not it's a roller block. You had the intake off... ignoring the colors, did the shape of the casting look like this:



Or like this:



Note the machined flat areas in the first picture over the lifter bores and the 3 posts with tapped holes in them in the center.

If the first picture is accurate, then it will cost you probably $500 or so including a cam. If the second, it will be $700-$1000 including a cam.

Steven6282

Hrm, I can go one better than simply telling you which one it looked like:



I took pictures while I had everything apart

So I think it looks most like the first picture. You said that would probably cost me $500 including a cam, but $500 for what?

Can you link the heads you are talking about on jegs?

vwdave

I donno if its mentioned, but have you checked your valvesprings? I got a bad set from a AC Delco crate engine.

InfernalVortex

iTrader: (4)

http://www.jegs.com/i/JEGS+Performan...14022/10002/-1

Do a search on your own to confirm as much as possible before you plunk down money, but word on the street is that those are the Pro-Filer heads. Look up pro-filer on here and you'll see a lot about them, all of it good.

You definitely have what was once a roller block. Im amazed they didnt give you a roller cam, but whatever. This is great news for you.

You will need to buy a spider and dogbones and a cam retainer. You can source that from a junkyard if you like, or you can buy new.

Spider and Dogbones:
http://www.jegs.com/i/Edelbrock/350/97386/10002/-1

Then you need a cam retainer. Im not sure which of these you need, though.
http://www.jegs.com/i/GM+Performance...68501/10002/-1
http://www.jegs.com/i/GM+Performance...88128/10002/-1

And then you need a set of OE style roller lifters.
http://www.jegs.com/i/GM+Performance...99225/10002/-1

And then you need a camshaft....
http://www.jegs.com/i/GM+Performance...02586/10002/-1
http://www.jegs.com/i/Comp+Cams/249/08-422-8/10002/-1

And then it's just a matter of setting up your valvetrain. The LT4 hotcam will be the most forgiving as far as affordable, cheap springs. You may even be able to use what you get with those jegs heads, but maybe not. Roller cams are superior in every way, but they do require more heavy duty components. Try to stick with the springs the manufacturers recommend. For the hotcam you need a pretty normal figure of 100 lbs on the seat and 300 lbs open... the jegs heads have springs taht are pretty close to that, I think, actually. The Comp roller is much more aggressive, you may need 120-130lbs seat pressure or so, so a little stiffer spring is required for those.

The last major difference is pushrods. That's something you'll have to figure out on your own. Should cost between $75-$125 for something reasonable, but what you have will not work.

And by my math, that sits you right on at $500. Understand that if you had a flat tappet block, it would likely cost you $300-$500 more to do the conversion, so that's why I say it's great news that you have a roller block.

Ugh, I've forgotten, you will need a new timing set too. Roller cams have the timing gear bolts much closer together. You dont need anything super fancy, just get a quality set. Should be less than $100 for one. If on a budget, I would probably get this, it's more than likely factory stock on most roller cam F-bodies and vettes etc.

http://www.summitracing.com/parts/NAL-12371043/

I tend to trust OEM parts for stuff like this. If they factory was willing to warranty it, I'm happy to run it. If you wanted to go for a double roller timing set a lot of people would support that notion, but I wouldn't mind a new GM single roller chain. Plus sometimes with a double roller you have to grind away for clearance on the block. not worth it in a healthy running engine to risk the metal shards. If you want something REALLY stout and single roller, this will do great and not break the bank, but the GM chain is fine:

http://www.summitracing.com/parts/CLO-9-3157/

And you dont really need the whole kit, but if you're curious, here you go:

http://www.jegs.com/i/GM%20Performan...0002/-1?CT=999

It's not a bad deal considering you get the nice rockers in the package, but it doesnt include pushrods or lifters, and you'll very likely already have rocker arms and retainers, etc, etc.

And remember the LT4 hotcam's specs assume 1.6 rockers, so if you use 1.5 rockers, it will be slightly more tame. .500/.500 lift and maybe slightly shorter duration numbers, but it's still a medium sized cam. Good for a quick streetcar. I'd suggest, in general, staying with stock ratio rockers. higher ratios complicate the valvetrain geometry.


And it may seem like a lot to take in, but it'd be a VERY worthwhile endeavor. If you dont want to blow $1000 on heads, just get some 083 TPI heads in decent shape, or find some reconditioned ones. Should cut $500 off of it. A hotcam and TPI heads with your RPM intake should get you to about 300hp. Should be a blast to drive and still get decent gas mileage and drivability, etc.

Steven6282

Ehh, I don't understand half of what you just said lol, which is why I paid someone for this engine I didn't want the headache of trying to figure it all out on the engine for this car Also It looks like it would end up costing me 2/3rds what the entire engine has already cost me (looking at ~1600 going with the jegs heads you linked) just to get it to what the engine is supposed to already be? Meaning I'd have 4k invested in just the engine itself, and if I spent 4k on a crate engine then I'd have something a lot more powerful (supposedly). Also, both of those cams you listed look like they have a lot closer duration than mine does now. Wouldn't that cause me to loose my nice lopey idle sound? That is one of the things I really want to keep regardless to what I do. I like for the car to sound like an old school 60s / 70s muscle car.

I'll just wait to see what the engine builders say, and if they try to say they aren't going to do anything to fix the engine being lower hp than it should, I'll use these numbers (possibly the cheaper heads) as reasons they need to refund me half of what I paid for the engine, because that is almost how much it will cost me to get it up to where they said it should be.

Thanks for the advice and links, if I end up doing this in the future I'll try to make more sense out of what all you just said haha But honestly, if I were going to do this, I might as well spend a little more to get another block, get it machined, and completely start from scratch.

InfernalVortex

iTrader: (4)

Power costs money. If you built it yourself you wouldn't come out that much farther ahead to be honest. If you get the aluminum heads I listed you'll probably be closer to 350-400hp. If you get some regular TPI heads, you'll be right around 300, and you'll be at around $1000 invested.

It might not sound quite as lopey, but it will make a LOT more power. Modern cam technology, even for flat tappet cams, allows so much lift for a given duration that a cam that sounds like what all the muscle cars sound like today because people put giant cams in them, wont be very drivable. It wont be a very nice street car. If you want to go bigger on the cam, feel free to do it, but it will cost you a wee bit more money in valve springs and a little more money for a name brand roller cam. If you must go bigger, the Comp XR276 is pretty mean.

The specs you listed on your cam are "270/224 .440" A bit vague, but Im going to assume you got a 224/224, 270/270 (Advertised duration), with .440 lift cam. That's kind of weird and Im not sure I beleive all of those numbers. .440 lift is absolutely tiny. Most cams in that range are in the 210/210 duration range, not in the mid 220s. I cant find anything like that on any of the big websites, so maybe the specs are wrong misleading, typo'd, whatever. Advertised duration is measured different from manufacturer to manufacturer, so perhaps the advertised duration is a bit more than 270. 224/224 will give a mildly lopey sound, but at .440 lift you're not really getting much out of it. If you put a bigger cam in as it stands the heads woudlnt support it anyway. It's a pretty well-matched setup actually, it's just not particularly fast.

Anyway,

Your cam:
224/224@.050, 270/270 adv .440/.440 lift

LT4 hotcam
218/228@.050 279/287 .500/.500 lift (w stock 1.5 rockers)
https://www.youtube.com/watch?v=Lmlqo0I8vT0

XR270
218/224 270/276 .495/.502
https://www.youtube.com/watch?v=ZFSXNYRL6as

XR276
224/230 276/282 .510/.510
sound clip: https://www.youtube.com/watch?v=ZjzPtVme_T0

They're all in about the same ballpark as far as how thei dle will sound, with the xr270 probably being the most tame. Notice how much higher the lift numbers are, though.

I hope that works out for you because I'd be pretty ticked off too. But unfortunately Im sure they will figure out some kind of reason to weasel out of it.Good luck, though.

But I will reiterate... you are a good cam and a good set of heads away from a truly stout motor. Depending on what heads you get, and what cam you get, you could be anywhere between 275-400hp. for $1000-$2000. It's still a 350 and you've already got a good intake. I would, however, avoid a cam that has an advertised powerband past around 5500 or so, just because I dontk now what kind of bottom end parts they used in that engine. It may not really be meant to spin to 6000 RPMs. The XR276 (224/230) is about as big as you'll want to go. The ONLY advantage you'd have in building a new shortblock is you could use some nice ARP rod bolts, and they may already be in there. A good shortblock is a good shortblock. There are small things like how far below the deck the pistons are that can affect things, but for the most part if it's fresh it's a good foundation.

Steven6282

I think mine sounds probably most similar to the XR270, but idling about 300 RPM slower.

http://www.youtube.com/watch?v=g3Vjr...ature=youtu.be

I dunno really, all 3 of those youtube videos sound like their idling faster than mine so not really sure if that is just not as much lope sound or that they are actually idling faster.

87350IROC

iTrader: (2)

I'm confused. I thought you were after more horsepower? Your cam has REALLY low lift regardless of what it sounds like. In fact, you have achieved that 60's sound complete with 60's low horse power as well. That cam you have is designed to make the lopey idle, not horsepower.

Steven6282

I'm after the horsepower this engine was supposed to put out with the advertised lopey idle when I bought it

I'm not trying to make some hp monster, 300 rwhp was my original goal but just under it would be fine.

I'd give up 100 hp if I had to, in order to maintain a 60s muscle car lope though

I know that it should not be necessary to give that lope up though, I have heard 500 hp cars making the same sound.

jmd

iTrader: (4)

In short,
"to convert your engine to roller cam, which the block is totally capable of, you need these parts"
Or you can scab them from a used engine including that 97 LT1.
I actually have the spider, dogbones, lifters and cam retainer plate all new in case you decide to go that way.

91phoenix

iTrader: (5)

It has been two weeks plus, what has the engine builder said? Are they going to do something for you?