gbettner

iTrader: (2)

I was curious about my "virgin" piston rod combo test so I switched out cylinder#2 with an old stock combo I had in the garage. Sure enough I gained about .010". Now the test was very crude and not completely accurate because I used a standard piston in a 4.030 hole but I got it as stright as possible and measured directly above the pin several times. I was in the range of .027 in the hole which is pretty darn close, it was definately higher up than the other slug. I think it's safe to assume my problem lies ALMOST completely in my reconditioned rods. I'm sure the machine shop would fight me tooth and nail about that statement but facts are facts.

Since I've ordered a straight edge I think my wisest move now is checking deck for straightness. I have a really strong feeling now the deck is going to check out "good enough" for me to feel much safer using my .015 shim gasket with a good film of copper coat. Thus getting me in between a .051-.056 quench on all 8 cylinders which will have to be liveable. If deck turns out too wavy, I'll regroup from there and either deck or go with the .026 gasket Skinny likes.

skinny z

Keep in mind that when your rods were "reconditioned" it doesn't mean that the centre to centre length on each rod was corrected to exactly 5.7". A batch of rods that was mismatched will remain mismatched after resizing. This may account for some of the variance. The rods from engine to engine may have even more difference in length. It may be fair to attack your machnist.
Checking the deck for straighness is only part of what's needed for the shim gasket to work. As I understand it, the surface finish is also of importance. How much so, I can't say. Like you said, see what the straighedge has to say and go from there.
Don't get too hung up on your quench before you work out a compression ratio. I think you'll find that you'll NEED the pistons .050"+ down in order to keep the SCR in line.

skinny z

For what it's worth I put your numbers through a DCR calculator.
Bore. 4.03"
Stroke. 3.48"
Head cc. 64
Gasket thickness. .015"
Gasket bore. 4.10"
Piston to deck clearence. .039" (average)
Piston valve relief. 6 cc
270 adv in/278 adv ex. 112 LSA/106 ICL
Quench. 054"
SCR. 9.9:1
DCR. 8.17:1
That's moving towards the DCR street/pump gas limit with proper timing.

gbettner

iTrader: (2)

Man Skinny that's good stuff. I didn't see any of these posts until this morning. Your a huge help! I gotta soak this in. Maybe your suggested .026 graphite gasket would be a better optimal quench? I'll call Lunati and get a solid answer on ideal CR for cam.

Thanks for going WAYYYYY above and beyond to help me out!

skinny z

Happy to help.
One thing about a 64 cc/ flat top piston 355 is that it WILL build compression pressure to an excess if the cam selected is too short. I went that route (albeit unintentionally) and found that the above combination with a prefered quench of .040" puts the static compression well into the tens. 10.4:1 in my case. It takes a cam with adv duration values in the 280's to bleed off enough pressure so as to keep the engine out of detonation. It's a fine balance if you're going for a maximum effort.
What you have to remember is that engines respond FAR more to ignition timing than they do to compression ratio. General thinking is that a full point reduction in the SCR (e.g. from 10:1 to 9:1) will see a reduction in output in the range of 4% for an average 1 hp/c.i. engine. Timing on the other hand can kill engine efficiency by many times that amount if it's not set to it's optimum value. That is, an engine should be allowed to take all the timing it can until power levels stop increasing BEFORE the onset of detonation. If you reduce the timing to stay out of spark knock, then you're giving up a lot more than the increased compression ratio might provide.
This applies to any normally aspirated engine, FI or carbed.

gbettner

iTrader: (2)

Alright got an official optimal static compression ratio from Lunati of 9:1, the tech said 9.5:1 would be even a little better. So my target is 9:1-9.5:1.

skinny z

That would put your dynamic/running compression ratio right around the 8:1 mark. That's a reasonable value for a street engine. Should build some decent low engine speed torque.
You won't be able to hit the "magic" .040" quench though. The piston will have to be down more than 50 thousandths to keep the compression in check. I doubt very much that'll it will affect your performance to any extent.

gbettner

iTrader: (2)

I'm sorry to need "spoon fed" but according to the target CR, calculations, and your above post, now the .026 graphite gasket is the best choice again or .028? The .026 would average me average quench of .065 and the .028 would give me an average .067 quench.

I can probably find a calculator link somewhere like your using but I'm sneaking peeks throughout the day quickly while I'm at work. I could order gaskets today if I lock this down to a solid decision but don't want to jump the gun without an official senior forum member "blessing". lol

skinny z

I've run through a few possibilties regarding your compression ratio. What I'm finding is that with a .026" gasket and the varying differences in the piston depth, you'll end up with CR values of 9.75 to 9.85:1.
Bump that gasket up to a .028" and the CR ranges from 9.7 to 9.8:1.
Those may appear high however when applied to running compression, the values are 8.1:1 for the .026 gasket on the tightest cylinder to 7.97:1 for a .028 gasket on the cylinder with the lowest piston depth.
There are a couple of things to consider. With your fuel injection and good tuning, I see no reason why a 9.75:1 SCR/ 8:1 DCR shouldn't work. I ran similar numbers (10:1 SCR/8:1 DCR) in my carbed Vortec headed 353 and while premim fuel was a must (I run 93/94 octane) it had a proper timing curve and ran very well. Decent highway mileage too at 22+ mpg.
Before I would make a choice there a few bits of data I would need. One is the piston valve relief volume. Flat top piston volumes are in the 5 - 7 cc range. It would be helpful to have your piston spec. The other is to verify your piston depth measurements.
This all has to do with selecting a decent gasket (and an economically priced one too). You could pick a .030"+ thick gasket and stay away from the compression edge but it may not be necessary if the numbers I'm looking for are in-line with the .026" gasket.
If Lunati likes 9 - 9.5:1 for that cam then at least you're on the right track.

86LG4Bird

iTrader: (1)

gb, I've just read through the last two days of posts here, and you're getting some damn good guidance from this guy skinny z
If anything, I'd say the advice of safe CR versus cam selection is on the conservative side. And I understand why; he's found that "popular wisdom" came up short on one of his recent builds

skinny, I know you were looking for data on what compression/cams people are running and, when I'm comfortable playing around in my unheated garage again so I can get some compression numbers, I'll send you some. I'm curious myself on the last engine I slopped together: L31 all stock except for ZZ3 cam and .015" gaskets. I didn't cc anything, just measured deck clearance (.023-.026) and checked block and head decks for straightness, so actual compression numbers will be far more uselful than any calculated CR. Anyway, I'm surprised to find that it's running amazingly well on 87 octane fuel and lugs like a tractor at 1000 rpm. I've played with timing to where it feels best (don't even know what it's currently set at), and it's almost impossible to get this thing to ping. Of course, it's a good time of year and it runs cool with a 180 tstat, so it's not all conclusive at this point.

gbettner

iTrader: (2)

Got ahold of Federal Mogal tech line, they told me the 4 valve reliefs on part # H345DCP .030 piston = 5cc's total.

gbettner

iTrader: (2)

Agreed 86LG4bird, I'm learning a lot and not taking it for granted. I've got tons of help from SkinnyZ and many others on this forum. Tuned performance, Sofaking, 86LG4 bird, SkinnyZ, Anethes, just to name a few.

I know it has to get old helping newbie guys like me all the time with the same old things but I SUUUUUURREEE appreciate all you guys help.

Really getting close here to a resolution on my build. This is SWEET!

skinny z

Just to clarify, my poor results didn't come from listening to "popular wisdom" but rather from NOT checking all of the vital measurements before I swapped short blocks from under my nice new heads. Going from a piston depth of .036" to a nicely decked .014" down makes up a LOT of compression. Lesson learned. But you get the point. Don't do as I did.

I feel your pain regarding an unheated shop. That's what's kept me from proceeding with my own re-build. I've promised myself that come April, sub-zero temps or not, I'm getting back at it.
I'll gladly take on your data when you get it. I'll resurrect that thread when I have my own engine assembled and can do the "after" part of the before and after compression tests. I'm hoping to drop from 10.4:1 to less than 9.9 and cranking pressures should drop from 200-205 to around 190+/-.

skinny z

Based on that and your previouly recorded piston depth measurments you're at or around 9.74 - 9.85:1 SCR.
DCR with the cam selected, installed as per the cam card (ICL 106) will be 8 to 8.1:1.
That's with the Victor Reinz/Clevite 5746 .026" x 4.100" gasket.
Be careful here as "popular wisdom" says that's workable. My own experience says it's workable too and as I mentioned with your FI, you should be able to get a good solid tune with the right amount of timing and proper air/fuel ratios.
I would think that it would need premium fuel to run without pulling timing but that remains to be seen. Look at 86LGs build that he's just described. 87 octane and no problems (albeit in favourable conditions as in cool temps).

gbettner

iTrader: (2)

Great! Thanks a million, I'll order the head gaskets now. Not as worried about seal now either. I owe you bigtime! I'll think of some way to repay you!

gbettner

iTrader: (2)

Having a little trouble, Summit has that part number listed at 4.125 bore. Is that the same thing as the 4.10 you stated?

86LG4Bird

iTrader: (1)

As I said earlier, I didn't measure the chamber cc's, but if you believe they're 64cc, then I'm about 8.1 DCR with the ZZ3 cam. And thinking about it some more, I did have that thing running and driving it to work in October, so it saw some 80 degree days for sure.
Based on that, I'd say that calculated 8.0-8.1 is a no-brainer = plenty of margin on 92-93 octane fuel.

gbettner

iTrader: (2)

Holy smokes, I just ordered my straight edge last night from S****T ( don't know if your allowed to name venders) and it already came! That's 20 hour turnaround! More to come in a couple hours with measurements.......

gbettner

iTrader: (2)

Good news, with my new machinists straight edge I can't see any light or even get my smallest feeler gauge (0.0015) under it at any point on the deck on either bank. I criss crossed both ways, horizontal, and verticle. Deck looks to be in really good shape! Yippee!

Now I''l look some more to try finding the .026 gasket with a 4.010 bore.

skinny z

Here's a link to the gasket I've been talking about.

http://www.summitracing.com/dom/part...5746/overview/

http://www.autozone.com/autozone/par...5_207540_15296_



Despite what some of the catalogs say, it's .026" thick with a 4.100" bore.

gbettner

iTrader: (2)

Thanks again Skinnyz, I got them ordered Friday. Should have em tomorrow.

Got the rest of my shortblock assembled and the pan on. Now might try hand lapping the valves even though machine shop said they were ready to install after valve/seat work they did. After that on to install height. All the fun easy stuff!

gbettner

iTrader: (2)

[
I know a thread isn't as good without pics so I've been trying for about an hour to get some uploaded. Don't know if it will work or not.

Didn't get my head gaskets today so I'm bored and thinking of stuff to do. One thing was finding true top dead center and I realized my smaller balancer on the vortec timing cover doesn't work too good. I'll have to fing something to make an accurate timing graph so I'm not guessing with the timing light. I guess I could just advance the timing light dial and sync the flash with the zero mark or just turn the dial until it zero's up and see what the gun reads.

Anyways tried to take a couple pics of the finished shortblock and heads.

gbettner

iTrader: (2)

The best that I can tell my stock pushrods are the perfect length. See pics of pushrod length checker in place and also rub pattern of roller rocker.

Only thing that worries me now is lifter preload doesn't feel good. I opted to re-use the stock lifters, they looked fine but now I'm trying to set properly the plunger disk seems bottomed out, as soon as I hit zero lash and go for my half turn it immediately started pushing down the valve. Tried the next lifter on #1 cylinder and same thing.

Best solution for a budget? Clean? Toss and find some better ones? I know I went big up to this point but I had to really sweet talk the wife into another 100 bucks for pushrods as soon as I nail down height. I really really don't want to add 150 more bucks on.

What do you guys think about checked pushrod length and lifter issue?

EDIT>>> Just thought of an option....... since it looks like stock pushrod length will work, I could use the 100 dollar pushrod money for new lifters and use the stock pushrods. Bad idea? Will they handle the increased spring pressures and abuse?



As always, thanks

skinny z

Couple of things:
Push rod length; I've always used the adjustable pushrod where a new length can be created and run through the checking process. However, it should be pointed that where it falls on the valve tip is secondary to the actual valve train geometry. It's the relationship between the rocker arm angle relative to the valve stem that's important.
Rather than using an a tool such as the one you have that approximates the parts you'll be using (rocker arms), the adjustable pushrod when used with your rockers will give a more precise result. If you want to explore it further, can you take a few additonal pictures like the ones attached with your pushrods and rocker arms installed?
One at zero lift.
One at mid lift.
Another at full lift.
If you orient the camera as I have in my pictures, we can see the side of the rocker and the valve stem and draw our alignment from that. What you're looking for (within reason) is a 90 degree angle relative to the pivot point of the rocker and the valve stem at mid-lift.
If I had a picture of my setup at mid-lift you would see that the 90 angle (in red) is pretty close. I'll have to fine tune that. Looking at the two pictures, I can see that at fully open the angle is much greater than when the valve is closed. This tells me that the pushrod used is too long. In the past, I've always gone for the "middle of the valve tip" method. That cost me set of valve guides.
It may be that your pushrod length is correct and this is how to verify that. If the pattern on the valve tip is centred or nearly so, then that's a bonus. Conventional thinking is that the contact has to be within about .030" of the edge of the valve and as narrow as possible (across the tip from intake side to exhaust side). This geomtry can be carried over to the pushrod side as well. Now we're talking about raising or lowering the rocker stud itslef to zero in a truly correct alignment. To me, that's really slpitting hairs and an all out race-effort, (not a short cycle drag racing engine necessarily but an endurance orientated engine).
Although a little mind-bending, you may find this article informative.

http://www.circletrack.com/techartic...y/viewall.html

Lifters; Can you actually see the plunger being depressed as you apply pre-load? (Is the intake manifold on?). I went through a set of well used retro-rollers and was able to push the plunger down by hand (using a pushrod) on some. Like you, when adjustingh pre-load, I could not achieve any resistance when rolling the pushrod between my fingers. Installing these resulted in lifter noise that could not be eliminated. That's not a good thing. If you're in the same boat, then yes, in all likelihood your lifters are toast.

gbettner

iTrader: (2)

I'll do 3 posts with 2 pics each.....

These first 2 are 0 lash/ no lift

gbettner

iTrader: (2)

[quote=gbettner;5733390]I'll do 3 posts with 2 pics each.....

second 2 pics are exactly 50% lift

gbettner

iTrader: (2)

Last 2 pics are full lift. Hopefully pics are usable for your requested research needs.

Thanks for the insane amount of help to a complete stranger!

gbettner

iTrader: (2)

Also, even though the lifter wasn't behaving earlier, I noticed the dial indicator bleeding off when I started getting alot of spring pressure on it. Now the plunger feels "spring loaded" and has the normal lash buffer zone like it should. Guess I just needed to keep some spring pressure on it for a minimal amount of time to get it "cooshed out". ( I don't think that's a word but it sounds right to me). It now seems normal to me. I guess by looking at all of them again the plungers aren't stuck all the way down like I thought. They were actually stuck/stubborn all the way up if that makes sense.

skinny z

I'm trying to see what others are up against as I'm working through this myself. A couple of the folks that have replied here have gone through troubles stemming from running a valve train that was thought to be setup properly but ultimately proved not to be.
I'd like to mark up your pictures but they're a little on the small side. Would you e-mail them to me?
PM sent.

skinny z

This is what I see.







At this point I'm not taking into account the contact point on the valve stem. Just the angular relationship between the lines drawn on the pictures. An equal amount of arc before and after midpoint is the target. That doesn't seem to be the case. I'm hoping others will offer up their experiences.
Question: Are you running this test on your hydraulic lifter?

gbettner

iTrader: (2)

Yes but the lifter plunger was bottomed out, I cycled the crank several times making sure I didn't have any varied dial indicator readings before official test was performed.

So your saying you don't think it's proper geometry? The checking tool I used is supposed to confirm perfect geometry by contacting both valve stem and pushrod. If it lacks contact to either, that measurement is what determines how much shorter or longer pushrod you need. You may already know that but wanted to make sure you know the only thing I'm going off of. Well that and the rub pattern on the valve stem.

Maybe we'll get some additional senior member "forum whales" to clear it up lol.

gbettner

iTrader: (2)

OK I see what you mean now, I clicked on the image and just noticed the thin red lines. That's pretty slick!

Test should be pretty accurate though, I measured max lift and cut it exactly in half for mid lift. I'll try to print them off at work tomorrow and see if I can get a protractor for readings.

skinny z

If your lifter was collapsed then the results of the reading are inaccurate.
What we're seeing here is what would happen if you ran a pushrod that was shorter by the amount of the plunger travel.
You have a few options to eliminate this:
1). Use a checking spring instead of the actual valve spring. (There's one visible in the picture of my valvetrain) I picked up a handful from the local hardware store.
2). Use a solid roller lifter in place of your hydraulic. It's very important that the solid has the same dimensions (as in pushrod cup height) as your hydraulic.
3). Use an OEM roller lifter that's been disassembled and rigged with a series of flat washers that take up the slack. This more or less makes a solid lifter and the dimensions are the same as your original.
Then you can run the test again. You'll notice a difference.

gbettner

iTrader: (2)

I didn't think of it that way! I'll rig up a lifter with washers tonight and re-test. Sorry for the trouble and thanks for pointing that out. Sorry I wasted your time with a bad test . I'll dive in on the "re-test" tonight.

Thanks again!

skinny z

Looking at your pictures that I've marked up, it can be seen that at zero lift, the angle drawn with the red lines is small (much less than 90°) , mid lift hasn't reached 90° yet and fully open is barely past a right angle. That tells me the pushrod is too short. When you say the lifter plunger was collapsed, then the pictures reflect that.
It may be that when you run the test again, either with a proper lifter or with checking springs, you'll find that the geometry is coming in-line and will compare with the results you got with your checking tool.

Since you'll run the test again, set up the camera so that the rocker trunion is centred in the picture and we can get a good look from the side. It's helps in the analysis if all the pictures are more or less the same.

If you don't get any additional hits here, I'd like to post yours and my images in a new thread and solicit comments that way. I find that after a thread like this has gone on for a few pages, that new contributors aren't as likely.

gbettner

iTrader: (2)

I spend forever dismantling lifter, removed spring and put in washers to the point it was about right (just a smidge of a gap under snap ring, close as I could get it).

Of the 4 new pics here are full lift and mid lift

gbettner

iTrader: (2)

Now here is zero lift and new valve tip wear pattern from roller.

Thanks again Skinny

gbettner

iTrader: (2)

If you don't get any additional hits here, I'd like to post yours and my images in a new thread and solicit comments that way. I find that after a thread like this has gone on for a few pages, that new contributors aren't as likely.[/quote]

By all means, no problem with you going with a new thread!

I tried better pics with trunion centered but it was hard holding cell phone in the same spot all 3 times.

InfernalVortex

iTrader: (4)

So Im having a hard time figuring out this rocker geometry voodoo.

You basically just want a 90 degree angle between the pushrod axis and the rocker arm (pushrod pocket across to the roller tip) at mid lift? That means a dial indicator at least, right?

Im not quite sure I understand how you can do this if you have hydraulic lifters. Do you need checking springs?

skinny z

Infernal raises a valid point about looking for mid lift. Looking at the marked up pictures, a more precise set of measurements may make a difference in whether it's a go or no go situation. Does your home-made solid lifter have the plunger right to the top?
Looks close both by the angles and the contact patch. The contact is perhaps a little wider than it should be. That's something that gets sorted out when you nail down exactly the right length but you have to consider if that's absolutely necessary. I suppose if I was getting ready for the 24 hour race at Daytona, I'd be concerned but otherwise I'd have to really think about it. I did lose a set of valve guides and until I do my own "post mortem" and set up what I had a do an analysis like on yours I won't be able to say how much makes a difference.

skinny z

The 90 degree angle is relative to the valve stem and the centre of the trunion. In more advanced setups I've read that the pushrod angles are also pursued.
A couple of options are checking springs or a home made solid lifter made from a stripped down hydraulic roller packed with washers. It's important that the distance from the centre of the lifter roller to the pushrod cup is the same.

gbettner

iTrader: (2)

Just for assurance I took a pic of home made solid lifter plunger position ( top), the way I had washers installed inside, and a pic of the sequence of shims I used layed out on the towel.

gbettner

iTrader: (2)

Also, as crazy as it may sound, I may try dismantling and cleaning each lifter to restore to good "un gummed" condition to save 100 bucks.

InfernalVortex

iTrader: (4)

The trunion is just an axis. It has no reference orientation? Do you mean at mid lift that the top of the valve stem would line up with hte center of the trunion if you had a straight edge across the top of it? How do you even measure that?

skinny z

https://www.thirdgen.org/forums/tech...y-looking.html

gbettner

iTrader: (2)

Holy smokes this is not easy. spent a few hours last night and got 4 lifters completely dismantled, cleaned, lubed, and reassembled. My hands hurt and still have 12 more to go. Think I'll get an adjustable pushrod ordered while I spend the weekend rebuilding lifters.

skinny z

The adjustable pushrod makes the setup much easier. I use this Comp piece:

http://www.summitracing.com/int/part...02-1/overview/

It has a scale on it and the results and as easy as reading the scale to determine what length pushrod fits your application.
I'm thinking you're very close if not good to go at this point. With the smaller lift cam and the 1.52 ratio rockers, the amount of leverage you're applying to the valve tip is reduced when compared to something more aggressive. As a result the stresses on the valve tip (and consequently the valve guide ) of being less than 100% perfect isn't as great as it might be otherwise.
Still for 20 bucks (and Summit's incredibly quick turnaround shipping times) it's a cheap investment and lessens the amount of work it takes to run the tests. This will leave you more time to clean your lifters.

gbettner

iTrader: (2)

Thanks man! Ordered and on the way!

gbettner

iTrader: (2)

Pushrod geometry pics all done and Edge converter showed up today. She's a bute!

nate85ta85

How long TYPICALLY is the life of vortec heads? I can pick up a set with 100,000 miles on them for $100 bucks. There is nothing currently wrong with them and I can get machine work at a reasonable price. I'm just wondering if they will last, or if its more of a money pit situation. I currently have some of the worst flowing heads GM ever produced so anything should be a step up.

Putting them in a 355 with a mild cam... .470 lift flat tappet...
I will only put about 5000 miles on it a year at most...

Let me know what you guys think. Thanks