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#87833 - 11/22/15 10:14 PM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
CNC-Dude #5585 Offline
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Its not so much the cam you should question, but the other components that also can contribute to inaccuracies that are involved in this process. If you don't at least check it, you won't know where it is. And if it doesn't perform as expected, you'll always wonder "what if".
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#87834 - 11/22/15 10:49 PM Re: 67 Camaro - Blown 250 [Re: CNC-Dude #5585]
TurboCamaro Offline
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Originally Posted By: CNC-Dude #5585
Its not so much the cam you should question, but the other components that also can contribute to inaccuracies that are involved in this process. If you don't at least check it, you won't know where it is. And if it doesn't perform as expected, you'll always wonder "what if".
I understand what you're saying, but I'd like to check it without buying the required tools. I've had some success with borrowing tools from the local shops. You guys think a typical auto repair shop would carry the dial and degree wheel or is it more of a machine shop set?

Ian
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#87836 - 11/23/15 06:27 AM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
gbauer Offline
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Originally Posted By: Ian67
It's all stripped now but I took a ton of pictures at the time.. I don't have the exact angle you want though. The bottom one is alright but doesn't show the oil pump.

Ian


Those pics were a HUGE help, Ian! Thanks!

I was able to get my hand in there and pull the oil pickup tube down a hair. That was just enough to stop the clanging.

Can't say thanks enough!


Onto the cam gear: If you haven't ordered one yet I found Autozone has them for dirt cheap.

http://www.autozone.com/internal-engine/...hv/4649_0_2635/

I'd recommend going into the store to order it though. Also might want to order the retainer and spacer as well. Mine showed wear so the machine shop replaced it with one from their used bin that had no wear when they pressed on the gear for me.

The new gear will make a little noise. Not much but expect it when you fire it up.


The machine shop only charged me about $30 to put it on. Good to find a nice local machine shop that does race engines. Ask the guys at the parts counter when you buy your gear set. The place around the corner from me (Gunther's if anyone is looking for a great little machine shop local to Frederick, MD) has all sorts of goodies, sells the right oils, and is generally just good to deal with. I've bought a ton of stuff from them for little money and they've saved me more than once.


Edited by gbauer (11/23/15 06:30 AM)

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#87837 - 11/23/15 07:09 AM Re: 67 Camaro - Blown 250 [Re: gbauer]
stock49 Offline

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Originally Posted By: gbauer

The machine shop only charged me about $30 to put it on.


Cam gear installation is an easy DIY job. With the magic metallurgy one doesn't even need a press.

For mine I installed the spacer and key into the key-way on the cam and stuck them in the basement deep freeze for a day. The retainer plate also spent the night in there.

In the morning I put the cam gear on the gas grill on high for 20 minutes - to preheat - 600 degrees. I have 4x4x1 square of steel that I use in the shop for various purposes. I put it under the gear to retain heat.

Next the cam and key were put in my bench vise with snout pointing straight up. The retaining plate is then installed. I placed my dead blow hammer at the ready.

I retrieved the cam and hot-block from the grill with my insulated gloves. With a propane torch I finished heating the cam gear hub by going round and round with a high flame on the inside surface for about 30 seconds.

To my surprise the cam gear literally dropped into place - no need for the dead blow . . .

Had I needed to pound the hot square of steel would have gone on top of the gear - to take the blows from the hammer.

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#87838 - 11/23/15 07:22 AM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
CNC-Dude #5585 Offline
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Originally Posted By: Ian67
Originally Posted By: CNC-Dude #5585
Its not so much the cam you should question, but the other components that also can contribute to inaccuracies that are involved in this process. If you don't at least check it, you won't know where it is. And if it doesn't perform as expected, you'll always wonder "what if".
I understand what you're saying, but I'd like to check it without buying the required tools. I've had some success with borrowing tools from the local shops. You guys think a typical auto repair shop would carry the dial and degree wheel or is it more of a machine shop set?

Ian


No, I wouldn't think a general repair shop would have these type of tools. These are more typically found in performance oriented hot rod shops and performance oriented machine shops. But, you'll just have to ask around.
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#87839 - 11/23/15 07:55 AM Re: 67 Camaro - Blown 250 [Re: stock49]
gbauer Offline
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Originally Posted By: stock49
Originally Posted By: gbauer

The machine shop only charged me about $30 to put it on.


Cam gear installation is an easy DIY job. With the magic metallurgy one doesn't even need a press.

For mine I installed the spacer and key into the key-way on the cam and stuck them in the basement deep freeze for a day. The retainer plate also spent the night in there.

In the morning I put the cam gear on the gas grill on high for 20 minutes - to preheat - 600 degrees. I have 4x4x1 square of steel that I use in the shop for various purposes. I put it under the gear to retain heat.

Next the cam and key were put in my bench vise with snout pointing straight up. The retaining plate is then installed. I placed my dead blow hammer at the ready.

I retrieved the cam and hot-block from the grill with my insulated gloves. With a propane torch I finished heating the cam gear hub by going round and round with a high flame on the inside surface for about 30 seconds.

To my surprise the cam gear literally dropped into place - no need for the dead blow . . .

Had I needed to pound the hot square of steel would have gone on top of the gear - to take the blows from the hammer.


Yes but my way the liability was on the machine shop. That's worth $30 to me.

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#87840 - 11/23/15 08:26 AM Re: 67 Camaro - Blown 250 [Re: CNC-Dude #5585]
stock49 Offline

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Originally Posted By: CNC-Dude #5585
Its not so much the cam you should question, but the other components that also can contribute to inaccuracies that are involved in this process. If you don't at least check it, you won't know where it is. And if it doesn't perform as expected, you'll always wonder "what if".


I haven't yet done the degree wheel on my build - I guess I will eventually. Used wheels show up on ebay all the time.

The cam-doctor card tells the story of the timing events clearly enough. My dial gauge tells the story of actual lift (which is always shy from the theoretical rocker-ratio) . . .

Have you ever tweaked a cam with offset key?
Pegasus Auto Racing - Offset Keys

I have not.

The stick is already ground - so all one can do is move the entire a profile +/- 1-5 degrees (based on the orientation of the offset) . . .

Perhaps something to consider after tweaking with lash adjustments (which is good for slight retarding on solids anyway).

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#87841 - 11/23/15 08:29 AM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
gbauer Offline
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For the novice: Why would you need to use an offset key? Don't you want the cam to open and close the valves at a set time and adjust the timing with the distributor?

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#87843 - 11/23/15 08:32 AM Re: 67 Camaro - Blown 250 [Re: gbauer]
stock49 Offline

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Originally Posted By: gbauer
For the novice: Why would you need to use an offset key? Don't you want the cam to open and close the valves at a set time and adjust the timing with the distributor?


The distributor adjusts spark timing events. An offset key moves the entire cam profile advancing/retarding valve events depending on the way the key is installed. It changes the position of the cam gear relative to the center line of the cam.

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#87844 - 11/23/15 08:40 AM Re: 67 Camaro - Blown 250 [Re: stock49]
CNC-Dude #5585 Offline
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Yes, i've used the offset keys and offset bushings in many engines where I had customers that didn't want to spring for an adjustable timing set. More times than not though, the cam timing events wont correspond accurately when you install a cam in the "straight up" orientation, because as with the "theoretical" rocker ratio, they also are assuming "perfect world" scenarios where all things are in perfect sync. Many aftermarket stock replacement timing sets for a lot of different engines are also designed to purposely retard the cam timing as much as 8 or more for emissions purposes(Fords being one of them), so its best to always verify and not assume you are close to what the cam card says.
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#87845 - 11/23/15 08:57 AM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
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I have to keep my purchases to Jegs, Summit, Ebay and Amazon as I'm in Canada on a small island with limited access to retail outlets. The Melling Gear set I posted on Summit has a Steel crank gear while the Autozone one is Cast Iron. My understanding is the Iron gear is weaker but quieter than steel. I'd consider the Autozone set but they don't ship to Canada and I don't get into the US much anymore.

I'll be installing the gear myself. I don't want to find out the Machine shop had installed the gear with a press and I had success with heating the damper a few months back. Thanks Stock49 for giving detailed instructions on the process.

I'll keep my eye open for used degree wheel and see if I can acquire the rest on the cheap. It'll more be for checking the setup at this point. Perhaps I can look into the offset key if adjustment is needed.

I left the crank and it's gear on a stand at home, does it "heat" on as well or press fit?

Ian
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#87846 - 11/23/15 09:24 AM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
stock49 Offline

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Originally Posted By: Ian67

I left the crank and it's gear on a stand at home, does it "heat" on as well or press fit?


I have drilled and tapped the crank for a retaining bolt. With longer bolt - two fender washers and a big socket (that fits over the crank snout) - you can drive the crank gear home via the longer retaining bolt. I did it by hand with 1/2" drive ratchet . . . no heat required.

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#87847 - 11/23/15 09:45 AM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
gbauer Offline
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I tapped mine on with a 1-1/4" galvanized pipe nipple and a hammer. Don't pound it on but you can do it gently and get it on just fine.

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#87852 - 11/23/15 09:51 PM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
TurboCamaro Offline
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Alright... machine shop work aside. I want to compile a list of items (tools/parts) needed to complete the build. I want to leave nothing out as I'd like to get most/all of it on one more order from Summit.

Melling Steel/Alum Crank/Cam Gears
Complete Engine Gasket Set
Turbo Oil Supply and Return Lines
Camshaft Degree Kit (Wheel, Dial w/Stand and TDC tool)
Plastigauge (to confirm various clearances)
Feeler Gauges Set (more clearance checking)
Piston Ring Compressor
High Temp VHT Engine & Header Paints
Hole Saw (oil pan drain install)

Please let me know if I'm missing anything significant for engine and turbo component install. At this point all parts on the head are stock and cam bearings will be installed by the shop. I obviously have all the basic wrenches and and whatnot used to disassemble the engine.

Ian
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#87855 - 11/24/15 07:22 AM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
CNC-Dude #5585 Offline
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I have crank hubs made for all the different engines i've built and the degree wheel bolts to the faces of these hubs. Most kits however only offer components to allow the degree wheels to bolt directly to the front of the crank, so make sure you drill and tap your crank snout if you haven't already or you wont have any way to affix the degree wheel to the engine. I also have a cam degreeing tutorial that I wrote as a tech article for several national magazines that you can use as a backup to help step you thru the process. I can email it to you if you need it.
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#87856 - 11/24/15 09:07 AM Re: 67 Camaro - Blown 250 [Re: CNC-Dude #5585]
TurboCamaro Offline
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Originally Posted By: CNC-Dude #5585
I also have a cam degreeing tutorial that I wrote as a tech article for several national magazines that you can use as a backup to help step you thru the process. I can email it to you if you need it.

That would be great. Not going to need it for a little while but feel free to send it to ian1331@gmail.com. I've got a list of machine shop services and drill/tap the crank is on it. Thanks!

Ian
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#87858 - 11/24/15 02:55 PM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
CNC-Dude #5585 Offline
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No problem! Just let me know when you are ready for it.
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#87859 - 11/24/15 03:01 PM Re: 67 Camaro - Blown 250 [Re: CNC-Dude #5585]
TurboCamaro Offline
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Originally Posted By: CNC-Dude #5585
No problem! Just let me know when you are ready for it.

Oh I'm ready now.. I can review it now to ensure I understand it all when the time comes. So feel free to send it when you get a chance. Thanks!

Ian
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#87962 - 12/04/15 03:01 AM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
TurboCamaro Offline
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Sent the original pistons back and now ordering the new ones through Tom. Machine shop suggested I go with the dished pistons and aim for 8:1 compression for lower octane. I have the meth injection system to supplement either way. In the mean time, I have a couple queries...

Here is my cam card:


Will my stock valve springs hold up to that lift? On Gbauer's recent lifter/cam thread (now I know why he wanted the pump clearance pics) I read the springs hold up to 450 then maybe 500 and then someone mentioned needing to replace them was "a myth". I'd like to use all stock parts on the head, at least for now.

I'm putting my new forged pistons on stock rods. For a goal of 300-350HP, is this dooming my build? Obviously anything can happen, but I've read people say "I've had stock rods to XXXHP for X years with no problem" and others piss on the idea of cast rods with any Turbo. Is this likely not an issue for me or is it really only a matter of time before they go?

Ian
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#87966 - 12/04/15 06:29 AM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
gbauer Offline
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Yes. You need new springs. Why risk dropping a valve on such a nice, new engine when springs are $50? That's a good meal and a beer for you and your wife.

Rods? I want to know this one as well.

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#87972 - 12/04/15 10:49 AM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
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I don't mind replacing the springs and have confirmed my .499 lift would be asking for trouble with the stock springs... Might work.. For a while.. But wasnt going to last forever.

I'm thinking of getting these springs from Summit (Howard 98214) and those blue Viton Umbrella Seals Tom has referenced in several threads. However I might get these matching Howard 93350 ones if they'll fit; fairly limited details. I've got an email into Howard Cams for more info.

Anyone able to tell if those springs will be a direct replacement for stock springs?

Ian
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#87974 - 12/04/15 05:09 PM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
Mean buzzen half dozen A.K.A. Hank Offline
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8:0 is too low compression, it will be sluggish , slow to getting boost.
Bad mileage.
I would shoot for at least 9.0 compression ratio, you have a descent size cam & if you are only shooting for 300-350 HP that will require low boost.

MBHD
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#87975 - 12/04/15 06:25 PM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
TheSilverBuick Offline
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Originally Posted By: Ian67

I'm putting my new forged pistons on stock rods. For a goal of 300-350HP, is this dooming my build? Obviously anything can happen, but I've read people say "I've had stock rods to XXXHP for X years with no problem" and others piss on the idea of cast rods with any Turbo. Is this likely not an issue for me or is it really only a matter of time before they go?


They should be forged rods, not cast. Only three things will get the rod, lots of rpm, hammering them with detonation (at a level that would probably destroy the forged pistons), and an obscene level of boost making a lot more than 350HP.

Simple math, 350HP/6 = 58HP per rod. 58x8 = 464HP for an equivalent V8. Big block Buick's have factory forged rods and many are built with stock rods making in excess of 500-550HP, usually with a heavier piston on the end of the rod. You're not even close to pushing the limits of the stock rods (changing the bolts out wouldn't hurt though...), nor a 7 main supported crankshaft.
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#87976 - 12/04/15 07:09 PM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
Mean buzzen half dozen A.K.A. Hank Offline
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Yes, the stock rods are forged.
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#87978 - 12/04/15 09:18 PM Re: 67 Camaro - Blown 250 [Re: TheSilverBuick]
TurboCamaro Offline
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Originally Posted By: TheSilverBuick
They should be forged rods, not cast.

Thanks SilverBuick and MBHD. I've read about casting and forging parts but obviously can't tell the difference by looking at them. I observed some rough edges alog what looked like the seam line of a mold and assumed they were cast. I don't have a great picture of it but...



So.. I doubt Tom has ordered my new pistons yet so the target compression isn't final, but the machine shop was fairly convincing a lower compression like 8:1 would support good milage, 87 octane, quick spooling and a mid-high power curve. They said the turbo would need to boost a bit more to get the power but it would be less prone to detonation and work well for me. I'd like to think they were taking all my components (turbo size, external wastegate, water/alc injection, cam) into consideration but I don't want bad mileage or sluggish low end performance. I'm not a fan of conflicting information. I'll have to look into this more over the weekend.

Ian
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#87982 - 12/05/15 11:13 AM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
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Those are forged. Forged have the flat smooth'ish parting line, cast is a thin ridge parting line. Below is a comparison of a cast (left) and forged (right) rods from the same type of engine.



As for compression. What I'm always told is, particularly for small engines (I count these as small..) is low compression will make them feel underpowered and lazy at low rpm, where higher compression will make a bit more HP/TQ off the line before the turbo spools, making a more even powerband/feel. I agree with your machinist on that 8.0'ish compression will be easy on your fuel bill and live happily on 87 octane "most" the time depending on boost levels. Getting up around 9.0+ compression will require premium fuel just to be sure you don't accidentally ping the engine when boost comes in, particularly at low rpm. If your turbo is sized right, boost can come in fairly early in the rpm range and low compression can be a near win-win IMO.
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#87983 - 12/05/15 12:20 PM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
Mean buzzen half dozen A.K.A. Hank Offline
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Being you are only going to run 5-7 psi of boost pressure to get your desired HP 8.0 compression is way too low, your camshaft is going to bleed down cylinder pressure, therefore you would need to up your compression ratio.
Your are not running a stock camshaft were your Cyl pressure would be higher.
If you are looking to make the most power out of your combo, you would run low compression & run higher boost levels, but since you are not going for that goal & would like some zip out of it, make better for a daily driver, better mileage you need to bump up the compression ratio.
Going to run 8.0 compression is old school way of thinking & is not good advice for engines being built today not from years ago thinking.
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#87984 - 12/05/15 12:35 PM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
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Thanks for your comments guys.. Getting a lot of mixed opinions online (and here haha). Anyone else care to add to the debate? I really wanted to stick to regular grade fuel but not loose tons off the line. Would meeting in the middle at 8.5:1 be an acceptable compromise?

Ian
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#87985 - 12/05/15 01:04 PM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
TheSilverBuick Offline
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I'm in decent agreeance with Hank given your goals, you may want a bit more compression for the relatively low boost levels you are targeting.
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#87986 - 12/05/15 02:05 PM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
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Well I'll probably call Tom on Monday and get the pistons ordered. I had originally planned to go near 10:1 but the shop convinced me to go with 8:1 for saftey so I guess I'll meet in the middle with 9:1.

Thanks for your input guys.

Ian
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#87992 - 12/05/15 09:51 PM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
Mean buzzen half dozen A.K.A. Hank Offline
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If you are dead set on running just 87 octane you can just stick with 8.0 but how much more is getting higher octane gas 10 cents 20 cents more a gallon, and how often are you going to drive the car, every day daily driver?

I would just run 91 octane and not worry about any detonation, run alcohol injection , some type of boost timing retard device.
Is an intercooler an option for you?

Not sure of all of your goals for your vehicle, just drive it on the weekends, car shows, daily driver, what gear ratio are you running, manual trans, auto, car weight etc all have to take into consideration when planning a turbo car project.

MBHD
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#87993 - 12/05/15 11:04 PM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
TurboCamaro Offline
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I was fairly dead set on running 87 octane as its obviously the cheapest and gas in Canada is ridiculous. 91 is premium and is usually 20 more a litre. Today premium is $1.33 a litre ($5.32 gal). That would make 87 about $4.52 a gallon. I feel like a cheapskate evening talking about it but an extra $1.20 a gallon for pump gas will add up. On the bright side, I found a local supplier of methanol at $5 a litre. May end up being cheaper to inject a 50/50 of that.

Long story short, I'm glad you caught my low compression idea as with your info, and several articles online I'm convinced 9:1 or even a little over is ideal for me. The alc injection, intercooler and cam shown above should be safe enough and still "easy" to tune at 9:1.

Goals: Near daily driver in city/rural/small island roads, stock gears (2.73s?), th350 with shift kit, 67 Camaro (approx 2900 lbs).

Ian
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#87995 - 12/06/15 11:46 AM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
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I thought that those nice forged pistons that Tom has will take a stock 250 to abot 9.5:1 without any decking. The pistons go up just a little higher than the 307 flat tops. But maybe these are different pistons. How does one drop the compression? Special thick head gasket?

I do not recommend 6:1, too low. :-)
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#87998 - 12/06/15 01:13 PM Re: 67 Camaro - Blown 250 [Re: mshaw230]
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Originally Posted By: mshaw230
I thought that those nice forged pistons that Tom has will take a stock 250 to abot 9.5:1 without any decking. The pistons go up just a little higher than the 307 flat tops. But maybe these are different pistons. How does one drop the compression? Special thick head gasket?

I do not recommend 6:1, too low. :-)

I agree 6:1 is waayyy to low. I was orginally planning on 8:1 but I'm pretty set on 9:1 now. The flat top ones on 12bolt.com do get you into the mid-high 9's but he has a different set now with dished tops. If you custom order he can have Ross Racing make whatever size dish you want. I originally ordered flat tops but the machine shop owner was adamant a lower compression would be safer on my .070 overbored cylinders and allow me to pump 87 octane.

The dished pistons could be made as big (deep) as you need to allow for a lower compression. After reviewing the Inline 6 power manual further, and a bunch of online resources I'm confident my block will be fine with 9:1 while allowing me to meet my performance goals. Plus, if (when?) I decide to up the power, I'll be in a better position to increase boost.

Most of you guys are pros but if anyone wants a refresher I found this page on www.xcceleration.com was very well written and gave me a basic understanding of the low vs high compression topic.

Ian
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67' Camaro - Performance 250 build - www.TurboCamaro.ca

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#88001 - 12/06/15 05:29 PM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
gbauer Offline
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Registered: 08/11/14
Posts: 810
Loc: Maryland
Thanks Ian. That link was great.

So from what I'm getting from everyone and everything is a stock engine can run 87 octane at 6 psi safely. How much more pressure can be run if mid grade is used? Premium?

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#88026 - 12/08/15 12:22 PM Re: 67 Camaro - Blown 250 [Re: gbauer]
TurboCamaro Offline
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Registered: 08/10/10
Posts: 168
Loc: The Island, BC - Canada
Originally Posted By: gbauer
So from what I'm getting from everyone and everything is a stock engine can run 87 octane at 6 psi safely. How much more pressure can be run if mid grade is used? Premium?

I don't know much about that but I've read Snowman's turbo build thread half a dozen times and their is a lot of tidbits on what he was able to achieve with stock parts. Even though I've learned tons from his thread a lot of it was a lesson on how to take risks and pay for it later. I'd bet if the stars aligned you could go higher than 6# but it would increase the likelihood of detonation and inevitable part damage. The way I understand it, with a carbeurator setup and no timing retard device the tuning has to be spot on to achieve efficient power while avoiding knock. The higher end parts will take a lot more abuse before failing, which I may need to get the tuning right. Plus, with different torque levels, gaskets, weak cylinder walls and all kids of unknown precurser issues, one engine might hold up to 10# while the next is shot at 4#.

I'm kinda talking out of my ass just to give you my no-actual-experince opinion.

Ian
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67' Camaro - Performance 250 build - www.TurboCamaro.ca

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#88027 - 12/08/15 12:43 PM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
gbauer Offline
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Registered: 08/11/14
Posts: 810
Loc: Maryland
Sounds like trial and error are involved...

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#88028 - 12/08/15 01:22 PM Re: 67 Camaro - Blown 250 [Re: gbauer]
TurboCamaro Offline
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Registered: 08/10/10
Posts: 168
Loc: The Island, BC - Canada
Originally Posted By: gbauer
Sounds like trial and error are involved...

For tuning I think so. As for the stock engine capability, I think it's probably impossible to say what amount of boost they can handle. If they were all brand new from the factory you might be able to get consistent reports from people but no 2 are alike now, making it impossible to know.

As for tuning, The Holly 600 I have is going to be a guessing game for me. I've got it all rebuilt but it didn't come setup stock. Stock or not, I don't know the best initial setup for this oversized carb.

Right now it has a 65/75 jets, 6.5 Power valve and 31/32 squirters. I never provided pics of the rebuilt carb...





If anyone has any thoughts on a good starting point for carb jets/squirters for my 250 (intercooled cold air intake but no turbo) please share. I'll add the turbo and devils own kit once the engine runs "stock".

Ian

p.s. new pistons ordered with a 12CC dish targeting 9:1 CR
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67' Camaro - Performance 250 build - www.TurboCamaro.ca

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#88029 - 12/08/15 01:41 PM Re: 67 Camaro - Blown 250 [Re: TurboCamaro]
gbauer Offline
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Registered: 08/11/14
Posts: 810
Loc: Maryland
I'm pretty sure those jets are going to be way too big.

Stock should be:

Primary main jets 69, Secondary main jets 71, Power valve 6.5, Primary Nozzle 25, Secondary Nozzle 32

http://www.allcarbs.com/tech.php?art=21

Power valve should work though. The squirters are probably about right.

All that aside that's a really big carb. A 450 CFM is probably more of what you need. I'm only running a 390 though I feel like I'm on the light side.


Edited by gbauer (12/08/15 01:42 PM)

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#88030 - 12/08/15 01:51 PM Re: 67 Camaro - Blown 250 [Re: gbauer]
TurboCamaro Offline
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Registered: 08/10/10
Posts: 168
Loc: The Island, BC - Canada
Originally Posted By: gbauer
All that aside that's a really big carb. A 450 CFM is probably more of what you need. I'm only running a 390 though I feel like I'm on the light side.

I knew the carb wasn't purchased setup as stock but I also knew the stock setup wasn't going to work for a 250 with, or without a turbo. It's a big carb but the mechanical secondaries will allow decent control over my turbo power curve. The way I look at it, it's like having two 2 barrel 300cfm carbs... One for normal driving and the other to kick in when I mash the pedal, aka "Turbo Time".

Ian
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