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Topic Review (Newest First)
12-29-2012 04:06 PM
techinspector1 I got rid of everything except simple hand tools when I retired, so I have no Chevy pieces around here to reference, but if you take into consideration the O.D. of the bore at the chamfer top edge, it's gonna be a wider diameter than the finished bore. I don't like any part of the gasket overhanging the base metal, so would be more inclined to use a 4.100" x 0.026" #5746 gasket with a piston deck height of 0.012"-0.014". Of course, I also don't like a crevice that will be presented by using an overly large gasket bore. The mixture that lurks back in that crevice will never get lit when the plug fires and will contribute to dirty emissions if you have to test where you live.

Bottom line, measure the O.D. of the chamfer right at the block deck and use the closest diameter gasket that you can. That's just my opinion.
08-22-2012 04:11 AM
cobalt327
Quote:
Originally Posted by cobalt327 View Post
If you look up the specs on the 10105117 gasket, the bore diameter is 4.1"
BTW, the Summit catalog shows the 5746 gasket to either have, or to fit, a 4.125" bore. What I'm seeing elsewhere (including my own notes) is that it has a 4.1" bore diameter.
08-21-2012 10:53 PM
cobalt327
Quote:
Originally Posted by Silver Surfer View Post
Is there any chance that anti corrosion crap will ruin the engine oil?
No, it won't ruin the motor oil/beak in lube.

Quote:
Also I put the head gasket on there using minor torque on the bolts. It is a Victor Reinz graphite gasket and it left some minor residue on the head and block. I am wondering if I should wipe it off before reinstalling, or if the gasket is toast at this point. I can take pics if needed.

Here is the gasket I am using (says Clevite, but the package says Victor Reinz):
Clevite Engine Parts 5746 - Clevite Nitroseal Cylinder Head Gaskets - Overview - SummitRacing.com
Unless the backing has peeled away from the gasket core they should be OK to use. If you feel otherwise, obviously you can replace them.

Quote:
Which BTW look EXACTLY like the ubiquitous GMMP gaskets (although these are .028" and supposedly for 4.000" bores only). And I do happen to have two of these GMMP's in the garage, but the block is .060"...so I guess they are out of the question.
GM Performance 10105117 - Chevrolet Performance Composition Head Gaskets - Overview - SummitRacing.com
The 4" bore gasket is for a 4" nominal bore- that's to say the gasket should accept overbores up to at least 0.060". To be sure, simply measure the amount of bore that is showing w/the head gasket in place to be sure the gasket fire ring isn't overhanging the bore. Or measure the gasket bore- it should be around 4.090" to 4.1" for most 4" nominal bore gaskets.

If you look up the specs on the 10105117 gasket, the bore diameter is 4.1"- at least that's what my hand written notes say...
08-21-2012 08:40 PM
Silver Surfer Is there any chance that anti corrosion crap will ruin the engine oil? Especially during flat tappet cam break in (yes I have moly paste and ZDDPlus).

Also I put the head gasket on there using minor torque on the bolts. It is a Victor Reinz graphite gasket and it left some minor residue on the head and block. I am wondering if I should wipe it off before reinstalling, or if the gasket is toast at this point. I can take pics if needed.

Here is the gasket I am using (says Clevite, but the package says Victor Reinz):
Clevite Engine Parts 5746 - Clevite Nitroseal Cylinder Head Gaskets - Overview - SummitRacing.com

Which BTW look EXACTLY like the ubiquitous GMMP gaskets (although these are .028" and supposedly for 4.000" bores only). And I do happen to have two of these GMMP's in the garage, but the block is .060"...so I guess they are out of the question.
GM Performance 10105117 - Chevrolet Performance Composition Head Gaskets - Overview - SummitRacing.com
08-21-2012 12:33 AM
cobalt327
Quote:
Originally Posted by Silver Surfer View Post
OK taking the lifter apart was a snap! Much easier than I anticipated. When I got it apart I found a bunch of stinky yellow translucent liquid in the bottom. Pretty thin viscosity so I don't think this is oil. Is this some sort of rust inhibitor? I am guessing that is not good to have in an engine. Perhaps I need to take apart all the lifters and drain that crap out before they are installed??? I don't recall reading anything about lifter dissassembly in the included cam literature.
The fluid is just that- an anti rust measure so the lifters will store w/o problems.

There's no need to drain it from all the lifters though. As soon as the oil system is primed before start up, the fluid will be swept away.
08-20-2012 07:15 PM
Silver Surfer OK taking the lifter apart was a snap! Much easier than I anticipated. When I got it apart I found a bunch of stinky yellow translucent liquid in the bottom. Pretty thin viscosity so I don't think this is oil. Is this some sort of rust inhibitor? I am guessing that is not good to have in an engine. Perhaps I need to take apart all the lifters and drain that crap out before they are installed??? I don't recall reading anything about lifter dissassembly in the included cam literature.
08-20-2012 05:16 PM
cobalt327
Quote:
Originally Posted by Silver Surfer View Post
...there are so many people that say twist the pushrod until there is resistence while tightening the nut, or wiggle jiggle pushrods until they stop moving. I guess this is more of an issue with OEM stamped steel rockers and the ball and socket trunnion and/or OEM nut. Perhaps there just isn't enough tactile feedback that the system us now at 0 lash.
Jiggling the p-rod up and down as the clearance is removed allows you to hear and feel when zero lash is reached. Most guys find this easiest. This is mentioned at #4, here.

Quote:
What don't you like about this swipe mark I posted? I looked and it doesn't appear that I can't dissassemble these lifters easily. I think most lifters have a normal snap ring, but these Comp Cams lifters have some sort of bent wire retainer. I am not sure I can get them apart with my tools/skills without damaging them. I will do some research and see what I can come up with.
The witness mark you show actually looks good. What I meant was getting the witness mark while holding down on the valve side of the rocker while cycling the engine seems like a bit of a hassle to get right.

It's because you are at minus 0.200" from the stock length of 7.8" that I'd like to see the measurement verified. If not for that, I'd say the witness mark was OK. I've not used the rockers you're using- it could be they're responsible for the difference.

The lifters will disassemble easily. Compress the p-rod cup w/a pushrod. While the cup pushed down away from the snap ring, pop the snap ring out using a small screw driver or pick. A disassembled lifter can be seen here. You can use wheel bearing grease to fill the chamber- the grease won't ooze out under the pressure of a checking spring.

Quote:
I have a solid lifter, but the pushrod cup is quite a bit lower than where the plunger sits on a hydraulic lifter.
That's a problem- I'd recommend you use a hydraulic lifter made solid.

Quote:
Do you mean use a stamped rocker? I do have the old self aligning rockers from the Vortec laying around.
Sure. The tip will not give you as sharp of a swipe mark as the roller tip, but it should be enough to give you a good idea of any large-ish change in the swipe's position on the valve tip.

Quote:
I wasn't meaning to swap all 16 lifters permanently. I meant just use a solid lifter for checking geometry (I have a new one laying around). More on that in the next post.
My mistake- I misunderstood you.
08-20-2012 01:33 PM
Silver Surfer I created my own adjustable pushrod. From an old OEM pushrod, I cut out 1.75" from of the middle leaving two 3" end sections. Next I got a 6" piece of 3/16" all thread and use two nuts to adjust the overall length.

Are you saying use the solid lifter to measure then factor the delta in pushrod height when converting to a hydraulic lifter? I do have a 6" digital caliper capable (supposedly) of .001" measurements.
08-20-2012 12:54 PM
PatM Do you have an adjustable push rod and the tools necessary to measure the height difference between the working surfaces of the two lifter types? If you do, I believe the rest would be pretty straight forward.

Pat
08-20-2012 10:24 AM
Silver Surfer Thanks for the reply! Good info!

Quote:
Originally Posted by cobalt327 View Post
Are yiou using self aligning rockers?
yes

Quote:
Originally Posted by cobalt327 View Post
Just so we're on the same page, "zero lash" is when the clearance between the cam lobe, lifter plunger, push rod, rocker arm, and valve tip is removed. The lifter plunger must not be compressed until it bottoms out- only remove the clearance w/o any compression of the plunger. The ONLY compression of the plunger allowed is the 1/2 turn you're adding after reaching the zero lash point. If the plunger is bottomed out THEN 1/2 turn more preload is added, the valve will now be held off the seat and the engine will not be able to make any compression, so will not start.
Thanks for clarifying. I guess I got confused because there are so many people that say twist the pushrod until there is resistence while tightening the nut, or wiggle jiggle pushrods until they stop moving. I guess this is more of an issue with OEM stamped steel rockers and the ball and socket trunnion and/or OEM nut. Perhaps there just isn't enough tactile feedback that the system us now at 0 lash.

Quote:
Originally Posted by cobalt327 View Post
You may have read that the plunger should be midway between zero lash and fully compressed, or in the older factory manuals as much as 1-1/2 to 2 turns may have been recommended.

The basic idea is for the lifter plunger to be compressed enough that the lifter will compensate for changes in the valve train due to small amounts of wear and to changes in clearances due to temperature. This gives a fairly wide range of adjustment. But it has been found that under most circumstances, using 1/4 to 1/2 turn of preload works well.

Because motor oil isn't compressible, as soon as there's pressure applied to the lifter's pushrod seat, the lifter is basically solid. There is clearance that will allow the lifter to "bleed down" over time, but in the brief period of time that the lifter is cycling, the amount of movement can be dismissed as far as setting the geometry goes.
I think this really clears it up. The plunger should only be compressed by the amount of preload (1/2 to full turn) at any given time during operation.

Quote:
Originally Posted by cobalt327 View Post
I don't see how you're getting a good swipe mark using the method you've described. But in any event you need to use a solid lifter. You can use one like you are using and stack small washers into the center until it's a solid or you can use a solid lifter- as long as the seat (where the push rod sits) is the same height as the hydraulic lifters you're using.
What don't you like about this swipe mark I posted? I looked and it doesn't appear that I can't dissassemble these lifters easily. I think most lifters have a normal snap ring, but these Comp Cams lifters have some sort of bent wire retainer. I am not sure I can get them apart with my tools/skills without damaging them. I will do some research and see what I can come up with.

Quote:
Originally Posted by cobalt327 View Post
I would suggest you get or make a solid lifter, install the head gasket w/the bolts tightened to 40 ft/lb, and recheck the measurements to see if they vary from what you saw earlier.
I have a solid lifter, but the pushrod cup is quite a bit lower than where the plunger sits on a hydraulic lifter.

Quote:
Originally Posted by cobalt327 View Post
I'd be curious to see what the results would be using a different rocker. If you have a different rocker arm you can use- even a stocker- give it a try to see what it gives you.
Do you mean use a stamped rocker? I do have the old self aligning rockers from the Vortec laying around.
08-20-2012 10:19 AM
Silver Surfer
Quote:
Originally Posted by cobalt327 View Post
I wouldn't swap out to a solid cam and lifters unless you were going to use a more radical cam than the one you've chosen. It's also not a good idea to use the wrong type lifter on a cam (solid on a hydraulic for example), if that's what you were considering doing.
I wasn't meaning to swap all 16 lifters permanently. I meant just use a solid lifter for checking geometry (I have a new one laying around). More on that in the next post.
08-20-2012 06:36 AM
cobalt327
Quote:
Originally Posted by Silver Surfer View Post
Also, should I ditch the hydraulic lifters for this and use solid lifters so I do not have to worry about the plunger?
I wouldn't swap out to a solid cam and lifters unless you were going to use a more radical cam than the one you've chosen. It's also not a good idea to use the wrong type lifter on a cam (solid on a hydraulic for example), if that's what you were considering doing.
08-20-2012 06:14 AM
cobalt327
Quote:
Originally Posted by Silver Surfer View Post
I am mocking up the valve train to measure for correct pushrod length and I need some clarification from the pro's. I have read up a lot of valve train geometry lately and pretty much given up on the idea of setting up for midlift (smallest wipe area). Given my hardware I just do not think I can make it work, so I am just going for the center wipe.

First, here is my hardware:
  • SBC350, decked .020"
  • L31 Vortec heads, milled (.010" ?), OEM pressed in studs
  • Howard's Cams full roller rockers
  • Comp Camps XE274H (230/236 @.050", .490")
  • .026" Compressed thickness head gasket (although I am NOT using it in the mock up phase
Use the head gasket while doing the push rod measuring. The gasket won't be hurt; you don't need to torque the heads down to full specs, 40 ft/lbs is enough.

Are yiou using self aligning rockers?

Quote:
When I tighten the polylock it is very clear when it bottoms out/zero lash is achieved. Is it from this point that I should go another 1/2 to full turn?
Just so we're on the same page, "zero lash" is when the clearance between the cam lobe, lifter plunger, push rod, rocker arm, and valve tip is removed. The lifter plunger must not be compressed until it bottoms out- only remove the clearance w/o any compression of the plunger. The ONLY compression of the plunger allowed is the 1/2 turn you're adding after reaching the zero lash point. If the plunger is bottomed out THEN 1/2 turn more preload is added, the valve will now be held off the seat and the engine will not be able to make any compression, so will not start.

Quote:
Where does the plunger on a hydraulic lifter normally operate at in a running engine (as in what height)? Doesn't it normally stay at the very top of the lifter, and when it is bumped by the cam it goes down a few thousands of an inch?
The basic idea is for the lifter plunger to be compressed enough that the lifter will compensate for changes in the valve train due to small amounts of wear and to changes in clearances due to temperature. This gives a fairly wide range of adjustment. But it has been found that under most circumstances, using 1/4 to 1/2 turn of preload works well (unless the manufacturer's instructions say otherwise). You may have read that the plunger should be midway between zero lash and fully compressed, or in the older factory manuals as much as 1-1/2 to 2 turns may have been recommended. The problem w/using that much preload is the lifter can "pump up" under some circumstances, causing a loss of performance and possible damage.

Because motor oil isn't compressible, as soon as there's pressure applied to the lifter's pushrod seat, the lifter is basically solid. There is clearance that will allow the lifter to "bleed down" over time, but in the brief period of time that the lifter is cycling, the tiny amount of movement can be dismissed as far as setting the geometry goes.

Quote:
Maybe I should consider lash caps? Are those OK to run in a street engine?
Lash caps can be used, but they're usually not needed when using a street-type cam/valve train. You can simulate the use of lash caps by carefully positioning a feeler gauge between the rocker's roller and the valve tip to see what changes this makes.

Quote:
In this pic you see the where I am at with the 7.600" pushrod. The lightweight valve checking springs I got are pretty stiff. They are pushing the plunger on the hydraulic lifter down, so when I get to peak lift I use my hand to push the rocker down the rest of the way. I stop when the plunger reaches the top of the lifter. Is this OK?
I don't see how you're getting a good swipe mark using the method you've described. But in any event you need to use a solid lifter. You can use one like you are using and stack small washers into the center until it's a solid or you can use a solid lifter- as long as the seat (where the push rod sits) is the same height as the hydraulic lifters you're using.

Quote:
Right now I am getting a good centered roller wipe path with my adjustable pushrod set to 7.600". This "seems" short. When I tighten the polylock it is almost bottomed out on the stud shoulder. Is this normal/OK?
I would suggest you get or make a solid lifter, install the head gasket w/the bolts tightened to 40 ft/lb, and recheck the measurements to see if they vary from what you saw earlier.

I'd be curious to see what the results would be using a different rocker. If you have a different rocker arm you can use- even a stocker- give it a try to see what it gives you.
08-19-2012 10:19 PM
Silver Surfer Also, should I ditch the hydraulic lifters for this and use solid lifters so I do not have to worry about the plunger?
08-19-2012 07:25 PM
Silver Surfer
First time: valve train geometry/mock up questions

I am mocking up the valve train to measure for correct pushrod length and I need some clarification from the pro's. I have read up a lot of valve train geometry lately and pretty much given up on the idea of setting up for midlift (smallest wipe area). Given my hardware I just do not think I can make it work, so I am just going for the center wipe.

First, here is my hardware:
  • SBC350, decked .020"
  • L31 Vortec heads, milled (.010" ?), OEM pressed in studs
  • Howard's Cams full roller rockers
  • Comp Camps XE274H (230/236 @.050", .490")
  • .026" Compressed thickness head gasket (although I am NOT using it in the mock up phase

When I tighten the polylock it is very clear when it bottoms out/zero lash is achieved. Is it from this point that I should go another 1/2 to full turn?

Where does the plunger on a hydraulic lifter normally operate at in a running engine (as in what height)? Doesn't it normally stay at the very top of the lifter, and when it is bumped by the cam it goes down a few thousands of an inch?

Right now I am getting a good centered roller wipe path with my adjustable pushrod set to 7.600". This "seems" short. When I tighten the polylock it is almost bottomed out on the stud shoulder. Is this normal/OK? Maybe I should consider lash caps? Are those OK to run in a street engine?

In this pic you see the where I am at with the 7.600" pushrod. The lightweight valve checking springs I got are pretty stiff. They are pushing the plunger on the hydraulic lifter down, so when I get to peak lift I use my hand to push the rocker down the rest of the way. I stop when the plunger reaches the top of the lifter. Is this OK?

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