Which Roller Rockers Help?

[4X4HIGH]

Just wanted to get a few things put down here... cc of two different sets of 193 casting heads came up with 66 cc. I know for sure one set has not been rebuilt, so I doubt any valve jobs interfered with this...

Reassembled one of my TBI 350s (that I had just dismantled) just for these measurements:
DECK HEIGHT CLEARANCE ON PISTONS: .022
CENTER DISH ON PISTON: AT LEAST 10cc
OUTER DEPRESSION AROUND HIGHEST PART OF PISTON: AT LEAST 4cc(probably more like 5cc)

Using several different headgasket bore and thickness sizes, I COULD NOT calculate this motor to be more than 8.7:1 compression. EVEN USING A CHAMBER VOLUME OF 64cc I COULD NOT GET THE RATIO UP TO 9:1. The piston has too much relief in it. Going through several of my manuals I found mention of the '94-'95 year L05 getting bumped to 9:1 compression, with not much of a performance gain noted. All the listed ratios I have for the Vortec 5.7 say 9.4:1

There's a lot of talk here about too much compression with the 193 castings, and not a lot of talk about other equally important things that determine the static compression.

66cc combustion chamber, 10cc piston dish, .041" compressed head gasket, 4.166" gasket bore diameter (almost all SBC head gaskets), 4.030" cylinder bore diameter, .022" deck height, 3.48" stroke, with a 5.7" rod comes out to 9.106:1 compression ratio.

 

[nsxxtreme]

Reassembled one of my TBI 350s (that I had just dismantled) just for these measurements:

Damn!! thanks for going through the trouble.

I'm using flat top piston but I dont think i have to much compression. If I had to much compression I would expect the motor to ping, and that just isn't the case. Although the motor IMO does not have enough power. I don't know if I am just expecting to much.

Today while changing out my power steering hoses I noticed one of the spark plug wires was fried. So I purchased a new set of wires. I'm hoping and crossing my fingers this is where my power went. I wont know until I hook my boat up and try to make it up the highway hill that seems to just over work this motor. I so much would like to keep this truck. If I can make it up the hill at 65 I'll keep it, otherwise I'm hoping it will sell.

I purchased just a standard set of spark plug wires for now. I am missing the little thermal shields on my exhaust manifolds because they were a pain in the ass to put back on. What is a good set of spark plug wires that wont melt? I imagine those who use headers must also have the same issue.

 

[dyeager535]

You'd need to watch it while driving, with some sort of software or tool to see if your knock count is going through the roof. Not all "knock" is audible, and the knock sensor theoretically can pick up knock before you hear it, retarding timing without you knowing it. I can't recall how much it can back off, but probably as much as it needs to (up to a point) keep the knock back.

Losing one cylinder on a V8 however, reduces the amount of power output.

 

[nsxxtreme]

I dont think the burnt wire was the cause of my lack of power. I tried to make it up that hill yesterday with the boat attached and the only way I could come close to doing the speed limit is to drop it into second and floor it. It managed 55mph up the hill (4000rpms). I don't know what redline is.

I'm going to leave it on craigslist if it manages to sell someone will make me very happy. With gas prices the way they are it doesn't seem like people are wanting trucks.

I'm thinking about taking it to a local dyno just to find out how much real power this thing has.

 

[dyeager535]

If you take it to a good place, their setup will datalog while its running, and could certainly identify if there are any issues like running lean, or retarded timing.

No vehicle manufacturer states the RWHP numbers AFAIK, so with a dyno you'd have to factor in drivetrain losses to get the SAE net number for a decent comparison. Also it's known that different dyno's give different numbers, apparently sometimes due to calibration, or lack of, so even dyno numbers are not necessarily "correct". But at least they are something measurable.

When I get off my rear and tune my EFI, I'd like to get mine dynoed as well, just to see what mine is putting out. I don't think it's going to be anything special, just nice to know "concrete" numbers.

 

[nsxxtreme]

Anyone know of a dyno in the portland area that can do big trucks?

 

[scouthead]

66cc combustion chamber, 10cc piston dish, .041" compressed head gasket, 4.166" gasket bore diameter (almost all SBC head gaskets), 4.030" cylinder bore diameter, .022" deck height, 3.48" stroke, with a 5.7" rod comes out to 9.106:1 compression ratio.

I guess this was in response to what I posted, and not about nsxxtreme's motor, so I need to clarify a few things:

THe pistons I just measured have at least a 10cc dish in the center. THERE IS ALSO A LARGE BEVEL ALL THE WAY AROUND THE TOP EDGE OF THE PISTON. The creates a void between the cyl. wall and the top edge of the piston, and adds volume... AT LEAST 4cc (probably more like 5-5.5cc but just playing it safe with 4cc). The piston can now be considered to have a 14-15cc dish to it for the purpose of compression calcs. Right?
I was also refering to a motor with a stock bore, NOT 4.030, so I still don't think you can get the compression up to 9:1 with any kind of reasonabley (close to stock) sized head gasket.

Also, rod length shouldn't have anything to do with you static compression right?

66cc combustion chamber, 10cc piston dish, .041" compressed head gasket, 4.166" gasket bore diameter (almost all SBC head gaskets), 4.030" cylinder bore diameter, .022" deck height, 3.48" stroke, with a 5.7" rod comes out to 9.106:1 compression ratio.

Obviously if you took a piston off a short rod and mounted it on a longer rod it woud ride higher in the bore, but pistons are made to all kinds of specs, and I would think the Deck hieght measurement and the Crank's stroke would be the major players in calculating compresion?

I came into this because I am building a motor very similar to nsxxtreme's, and posts on this thread regarding the 193 casting heads and flat tops got me worried about how my motor (that I'm building now)would relate to the stock form. I wanted to bump from 8.5:1 to around 9:1 compression, and that is exactly what has happened. All my TBI 350 motors have 193 casting heads at this time.

nsxxtreme,
I would like to know a little more about your motor when you get the chance...
Injection upgrades? Headwork? Stock intake? Stock Cam? What kind of transmission?

 

[nsxxtreme]

nsxxtreme,
I would like to know a little more about your motor when you get the chance...
Injection upgrades? Headwork? Stock intake? Stock Cam? What kind of transmission?

My cam is listed one page back. Other then that I added 1.52 roller rockers. Everything else is stock. The motor runs fine from what I can tell just lacking in the power department. I have a 700r4 transmission with 4.56 differential gears. I origonally bought this thing because my RR transmission cost more then the entire blazer. So I just wanted something mainly to perform towing duties and also have a little fun in. I may have been a little to eager. I've never owned an american made car and I have always heard they had tons of torque. So I bought one thinking towing would be an easy task. This one has left a bad taste in my mouth for american made muscle.

My V6 Toyota tacoma could pull the boat up the hill at 70mph in 3rd. (stick shift)

My last ditch effort is to throw it on a dyno and pray something strange is going on. I think its running just fine and sadly this is all its got.

 

[scouthead]

Did you run a compression test after getting it running? You mentioned your machinist said to expect 150-170 psi?

Also don't know what kind of hill, or boat you are dealing with, But I've watched other people chase this kind of towing power, and ended up with diesels...
TBI350, to Vortec454, to Duramax.
Ford360, to another ford with a IH 7.3, to a newer powerstroke.
Neither guys had complaints about their trucks until they were towing something uphill...

 

[nsxxtreme]

Did you run a compression test after getting it running? You mentioned your machinist said to expect 150-170 psi?

Also don't know what kind of hill, or boat you are dealing with, But I've watched other people chase this kind of towing power, and ended up with diesels...
TBI350, to Vortec454, to Duramax.
Ford360, to another ford with a IH 7.3, to a newer powerstroke.
Neither guys had complaints about their trucks until they were towing something uphill...

Have not run a compression check yet. Just haven't really had the time. Truck runs great will even chirp the 35" tires from a dead stop by stomping on the gas. Even does ok with the boat as long as you don't go up hill.

As for chasing towing power I would not waste my time with an American made car ever again. Seriously it just doesn't make sense, to inefficient. I could tow that boat up that hill at 100mph with my RR no problem, with only 4.4Ls. My previous V6 Tacoma struggled at 70mph but it would still do it, and the boat would push it around when stoping. Would love to sell it and get another Land Rover product but with gas prices where they are at big truck aren't in demand. And I can't stop buying stuff for it damn it LOL...Just bought a carpet kit for it.

I'm still hoping that once I get it on a dyno it will show me something is wrong. I'm just not holding my breath.

Thanks to everyone that has posted all information has been helpful. Great forum here guys.

 

[Greg72]

...I would not waste my time with an American made car ever again. Seriously it just doesn't make sense, to inefficient. I could tow that boat up that hill at 100mph with my RR no problem, with only 4.4Ls. My previous V6 Tacoma struggled at 70mph but it would still do it, and the boat would push it around when stoping. Would love to sell it and get another Land Rover product...

If you honestly think there is some "magic" in a Land Rover or Toyota motor that helps it tow better than a Chevy, you are beyond our help here.

The truth is you are your own worst enemy. Honestly, think about it for a second and look at the advice you've received here vs. the actions you took to resolve your "issues". You wasted money on Chinese rockers (which don't add power), refused to consider exhaust headers (which DO add power)...tinkered and threw a bunch of parts at the motor until you had something that probably makes less power than a decent running stock 350 does. You run 35" tires on a tow rig (God only knows why) but never bothered to even pull the diff covers to confirm what gears you have....maybe they're 4.56s.... nobody, including you knows for sure.

You've solicited and received advice from some of the most knowledgeable guys on this site (dyeager, Thunder & 4X4HIGH to name a few)....these guys know their sh*t and if you listened to their advice instead of arguing with them, you'd already be raging up those hills with trailer in tow.

Go buy a stock Rover or Toyota, weld the hood shut to prevent your messing with it and you'll probably be happy forever.

 

[nsxxtreme]

You wasted money on Chinese rockers (which don't add power), refused to consider exhaust headers (which DO add power)...

At least make some sense if you're going to argue. Roller rockers do not subtract power they are the same as stock except for rollers. The cam I used should not subtract power. Everything else is stock except for the flat top pistons. So saying I make less power then a stock motor because of my parts well......ya that makes some logical sense .

I dont want to run headers why is that such a big deal? Yes I know they add power, they also add under hood heat and are a pain in the a$$. It's just a personal preference I don't want to deal with. I did't "refuse to consider them" I considered and chose not to run them.

If you honestly think there is some "magic" in a Land Rover or Toyota motor that helps it tow better than a Chevy

The magic is called more HP and torque out of a smaller motor and still passes a smog test. Sure I know you can build beasty 350 motors, but they wont pass a smog test which makes the motor worthless to me.

but never bothered to even pull the diff covers to confirm what gears you have....maybe they're 4.56s.... nobody, including you knows for sure

What makes you think you need to do this? I have an rpm gauge connected as well as measured my speed with a GPS through all 4 gears. The difference between gears is so drastic that its fairly easy to tell what gears you have. I trust math don't need a visual confirmation to tell me hundreds of years of math still works.

You run 35" tires on a tow rig (God only knows why)

Because I bought that truck that way. My tacoma had 33's And the fact the 35" tires make it look good why the hell not. This things "supposed" to have tons of torque lol at least that's what all of my american car owner friends say. I come from a family of long time devoted chevy owners. The devotion never made sense to me I didn't see the value in what chevy was offering so I chose a different route. The ONE time I listened against my better judgement I end up with a TURD. But hey I'll still have fun in the thing.

You've solicited and received advice from some of the most knowledgeable guys on this site (dyeager, Thunder & 4X4HIGH to name a few)....these guys know their sh*t and if you listened to their advice instead of arguing with them, you'd already be raging up those hills with trailer in tow.

And everyones advice is appreciated. No one is really arguing anything I'm not saying anyone is wrong or right.

You can hypothetically blame it on anything and we could play the guessing game all day, the dyno will tell the truth. Then we can all argue how the roller rockers that are the same as stock are robbing my power. The only thing that I see that could possibly by an issue is the cam or TBI is not functioning correctly. I have no prior experience with this truck the motor was ripped out the day I got it so I dont know of any issues it may have had. Or could be that the motor runs great and just doesn't have anymore power. I tend to believe she's giving it al she's got and she just ain't got no more.

 

[4X4HIGH]

Got news for you, changing the compression of an engine makes other componenets not play well together. You can't expect to just throw parts in an engine and have it make more power. Typically when you raise compression ratio you also need to install a bigger cam that matches the compression ratio you'll achieve, this also means more fuel which relates to a larger TBI and injectors, which also relates to a custom chip being burned. You can make BIG power and still be smog friendly, it's all in the parts that are chosen to work together.

Gregs roller rocker comment wasn't meant to mean that they make any less power but that if you're looking for more power you should have spent money on items that are known for a power increase such as headers. Roller rockers will definately help with resistance but much higher up in the RPM range than your engine is capable of going or where your planned use is.

 

[nsxxtreme]

Got news for you, changing the compression of an engine makes other componenets not play well together. You can't expect to just throw parts in an engine and have it make more power. Typically when you raise compression ratio you also need to install a bigger cam that matches the compression ratio you'll achieve, this also means more fuel which relates to a larger TBI and injectors, which also relates to a custom chip being burned.

imo the thing still runs slightly rich can smell it. The cam was listed a page or two back slected to make power in lower RMPs.

Gregs roller rocker comment wasn't meant to mean that they make any less power but that if you're looking for more power you should have spent money on items that are known for a power increase such as headers.

So lets agree to drop the discussion about the roller rockers since they have a nill affect at reducing power. So in the discussion lets assume other then money they are nill. The $150 some odd dollars I spent means nothing to me, I spend more then that on gas. And headers are also out because I don't want them. So now lets concentrate on "other" things that can make power. For example you might try "X" heads will flow better and work better and you dont need to change much. Or the cam you used won't work well with the compression your at. Those are useful comments that move the discussion forward.

Not trying to be an a$$ here but bickering over roller rockers that have a nill effect results in no progress.

Dyno will tell me a lot, I'm not one that likes to play the guessing game much. Sure guesses lead to possibilities but I like data before then making a decission, must be my engineering background I guess, pain in the a$$ sometime

 

[4X4HIGH]

Dyno will tell me a lot, I'm not one that likes to play the guessing game much. Sure guesses lead to possibilities but I like data before then making a decission, must be my engineering background I guess, pain in the a$$ sometime

With that being said, tell me what the deck height of your engine is, CC's of the heads you currently have on the rig, what is the actual bore diameter (4.030")? and from there i can have a better idea of if you have mismatched components. There is no way to tell actual compression ratio without all of that info (actually need a little more info like compressed head gasket thickness and also what CC's the piston valve reliefs are). Also are you still running the factory TBI unit and do you have an aftermarket chip?

 

[pseudomike]

I used these, affordable, and they clear the CB valve covers. They also have a 1.5 ratio version if thats what you need. No problems thus far.

http://paceperformance.com/index.asp?PageAction=VIEWPROD&ProdID=25862

 

[nsxxtreme]

With that being said, tell me what the deck height of your engine is, CC's of the heads you currently have on the rig, what is the actual bore diameter (4.030")? and from there i can have a better idea of if you have mismatched components. There is no way to tell actual compression ratio without all of that info (actually need a little more info like compressed head gasket thickness and also what CC's the piston valve reliefs are). Also are you still running the factory TBI unit and do you have an aftermarket chip?

Some of the info I don't know whish I did. Motor was bored .040 over used a stock felpro head gasket. Heads have never been milled. heads are 193s so 64cc? No head work done other then valve seats reground and seals replaced. Running the factory TBI with factory chip. Looked into a chip but I wanted dyno results before I paid someone to program me a chip without ever seeing the truck.

 

[4X4HIGH]

Some of the info I don't know whish I did. Motor was bored .040 over used a stock felpro head gasket. Heads have never been milled. heads are 193s so 64cc? No head work done other then valve seats reground and seals replaced. Running the factory TBI with factory chip. Looked into a chip but I wanted dyno results before I paid someone to program me a chip without ever seeing the truck.

Well, now you're back to the unknown. Heads can vary by as much as 4 or 5 CC's which is a big difference when trying to figure out compression ratio. Also without knowing the deck height once again there is no way to know "for sure" what your compression ratio is. I've seen deck height vary by as much as .015" and even front to back by as much as .025" and bank to bank by as much as .020". GM wasn't known for making the blocks very square from the factory. Unfortunately unless you're willing to pull the heads and actually measure your deck height on at least the four corners so we can come up with an average everything you do is just a guessing game.

I did some quick math and this engine is somewhere between 9.5-9.7:1 compression ratio with your given info. This is too much compression with an iron head for pump gas in a 6000 rig.

 

[nsxxtreme]

Well, now you're back to the unknown. Heads can vary by as much as 4 or 5 CC's which is a big difference when trying to figure out compression ratio. Also without knowing the deck height once again there is no way to know "for sure" what your compression ratio is. I've seen deck height vary by as much as .015" and even front to back by as much as .025" and bank to bank by as much as .020". GM wasn't known for making the blocks very square from the factory. Unfortunately unless you're willing to pull the heads and actually measure your deck height on at least the four corners so we can come up with an average everything you do is just a guessing game.

If the dyno tells me something strange I might just do that. But at that point I think I would start looking into getting a different set of heads.

 

[4X4HIGH]

The dyno isn't going to tell you anything about the inside of your engine. You will be able to find out if it's in fact running too rich or too lean and that's controlled by TBI sizing, injector sizing, and dwell time of the injector which means CHIP. You will also be able to see the timing curve but once again this is controlled by the CHIP.