Jeff@TotalPerformanceEng

iTrader: (6)

No its not accessable with the blower on.

I definately dont think 7.4's are the right length. With the .074 head gasket, it would be to short.
I've got the head almost off, so I will be able to do an accurate measurement.
I'm also sending the heads off to AFR for further inspection and rebuild. I should know more by the end of next week.

When you check the PR's with the motor torn apart, is it necessary to re-torque the heads? Or can you just set the heads on with the head gasket and make your measurements from there??

vettenuts

iTrader: (4)

I would put the head on with the old gasket if its an MLS gasket, and then torque to say 20 lb-ft for the measurement. Beyond that is bolt stretch and not a factor. Also, since the pushrods come in increments of 0.050" or 0.025" if you are near 7.400" a few thousanths won't make a difference.

99Fbody99

Man, how does this wind up in the Advance section.

a few items off the top of my head.

First item being that all push-rods although marked 7.XXX are not actually that length. Depending on the manufacturer it may be the "Actual over all length" or "Effective overall length". The difference is one will be shorter to the tune of .016"-.024" than the same length called out from another mfg.

Second item is its required to use a thread (intake) sealer. It has become common to use read thread locker on these fasteners. This may also account for a high breakaway torque on top of the usual issues with a bimetallic joints.

Regardless of how "tight" they were or were not it DOES NOT EFFECT the geometry of the valvetrain.

Next one up is you must have the motor assembled to the final specs to check anything. Before you tear it down simply make sure the cam is on base circle and rotate the fastener till there is no up and down motion (will move from side to side) of the rocker arm. Mark with a paint pen top and then rotate while counting the full turns on the marked heads. Typical target is 1.5 full turns till its seated. This will result in a preload roughly .060" and 2 turn will new .080".

The small changes in pushrod length that still allows for proper function (yes there is a range) will actually have minimal impact on the sweep path on the valve tip with the stock rocker arm/ pedastal combination.

If you use the search feature in the proper forum section you will find this information readily available.

Dave

On a side note, I have done enough 225s installs with 7.450" pushrods with stock GM MLS head gaskets that makes me think that with a gasket .024" thicker that it is very possible that 7.500" would be in the working range. Also, Trick-Flows are certainly one brand that is shorter than a brand labeled based on Overall length.

Spend 10 minutes and check for the answer and solution.

Jeff@TotalPerformanceEng

iTrader: (6)

Thanks for the valueable (yet sarcastic) info.

Since I have the motor apart, I will be verifying the PR length AND posting the info.
If the PR lengths are actually 7.50 I will be elated. I am willing to bet the farm its incorrect, but I am hoping its actually right.

As for the sealer on the intake side of the rockers. I am very aware of that. (believe it or not, I use the search function quite often) In this case, it looks like red RTV was used (looks like it at least). Not saying thats bad, I'm just mentioning it.
Also, I know 100% how to check the stud torque measurements.

I think your getting a few things mixed up. I didnt say the torquing of the rockers threw off the geometry. Theres 2 things going on with these heads. 1) PR length looks too long (as indicated in the wipe pattern.) 2) The lifter preload was out of this world. This looks to have been bottoming out the lifter and causing the loud knocking sounds. (At least thats my assumption at this point.)

"IF" the PR's were too long, and the preload to high, should I replace my lifters?? Even if they dont show any severe signs of damage?

Is there ANYTHING else I should be looking for?

One more thing.. Exactly "What" section do you reccomend for technical questions?? Its not like you guys are talking about splitting Atoms in this section.. I mean Jesus, I had questions about valvetrain issues, not how to tie my fuking shoes.. J/K

vettenuts

iTrader: (4)

With all the effort to get at the lifters, I personally would replace them as a precaution. Skoggins is getting in some of the Caddy lifters next week according to thier post on CF, you might want to get a set.

DrkPhx

iTrader: (15)

The picture of the valve tip looks exactly like the picture AFR posted in their thread about the valve tip recall. I think this may be your problem, or at least the root cause. I would contact AFR for confirmation.

Here's the thread with pics:
https://ls1tech.com/forums/generation-iii-internal-engine/611867-afr-s-resolution-valve-tip-issue.html

The 7.50 pushrod length is not that far off considering you are using a .074 compressed thickness head gasket. I used the pushrod length calculator in the sticky in the Internal Engine section and came up with 7.45 but that does not take in consideration a smaller base circle that is usually found on aftermarket cams. Here's a link to the sticky, scroll down to post #5 and download the calculator and save it.

https://ls1tech.com/forums/generation-iii-internal-engine/327734-cam-guide.html

FWIW - I would never use a allen wrench for that application, buy a set of allen head sockets so you can use the correct ratchet and/or torque wrench.

stevieturbo

I cant comment on a lot of this...

But. Just because you torque a bolt up to xx lbft....doesnt mean its that easy or hard to loosen it again !!!!
And yes, often if you tightened to say 30lbft, then tried to go to 40lbft, chances are the wrench wouldnt move any further. It is a pretty small step up.

Or maybe I just use a crappy torque wrench ( quite possible )

AS for the PR length. So you have un-milled heads, and stock rockers, stock block etc.

I cant see why, given you have a gasket some 0.025" thicker than stock, and a camshaft with a smaller base circle ( how much of a lift difference is there between your cam, and a stock one ?? ), why some people say you wouldnt need longer pushrods ? Everything there says you should need longer ones.

Thicker head gasket and cam with smaller base circle, will both require longer PR's

As for the noise.....would lifters that are bottomed out be noisy ?

I know my engine rattles a little, but the piston skirts are pretty small, so I just put it down to piston slap. Doesnt concern me.

For info, Im on stock LS6 block, un-milled Edelbrock heads, 1.7YT's and 7.40 trickflow pushrods, and stock GM MLS gasket at circa 0.050"
My cam has 0.581/0.591 lift....
Not sure how the base circle of that compares to a stock cam.

If your cam has 0.100" smaller base circle, than it stands to reaosn you will need a 0.100" longer PR to make up that difference, all other things being equal.

Jeff@TotalPerformanceEng

iTrader: (6)

So if you cant tell by the wipe pattern on the valve tip (pics above), you cant check by judging the turns to zero lash, and you cant tell by checking the torque of the studs, how do "YOU" check your lifter preload??
And I dont mean when installing them. I mean when they are already installed. Do you just not check or something??

The MAX reccomended torque is 22lbft on the studs. It was 24lbft higher than that.

And YES, a lifter being bottomed out will "Cause" valvetrain noise. It may not be the source, but it will definately cause it.

Yes, I have unmilled heads, stock rockers, stock block, stock lifters, and a mild cam 230/234 114 (I was never told the lift)

stevieturbo

Well, yes, your pre-load if its that many turns, is way too much ( assuming tightening on the base of the cam lobe )

And yes, the wipe pattern is crap.

I'll admit, mine isnt as measured as it could be. I made up a rough pushrod checker from an old stock pushrod, and used that to check with.

99Fbody99

You cant!

Again, you need to use the method I posted above when its fully assembled using the bolt turns till seat. Of coarse you can use a dial indicator and magnetic stand etc to come up with the same answer .

Also, the valve tip sweep area with the non adjustable stock rockers will not change with pushrod lengths as long as they are within the lifters range.

You have everything in front of you. Spend 10 minutes to come up with the FACTS.

Dave

Jeff@TotalPerformanceEng

iTrader: (6)

Really.....

So your saying the sweep area on the valve tip DOES NOT change if you have too long OR short of pushrods with a non adjustable rocker....

Seriously.. I know how to use the search feature. I'm not 4. But remember, the threads would NOT be there to search if people didnt ask questions.

I get your point about it. If your soo bothered about this thread then just dont reply..


Thanks for all your help guys. I've found what I'm looking for. I appreciate it.

Jeff

Phil99vette

iTrader: (11)

To get back on track, I still think that the problem lies or associated with the lifter cups. Its the ONLY part in the engine that could be able to produce a similar sound.

99Fbody99

I find it entertaining to read your responses to people trying to help you.

But, to answer you question the sweep will not change on the valve tip if the pushrods are within the operating range of the lifter. It does not matter if ts .025" or .150" preload on the lifter, the sweep is nearly identical with no change because the valve lift is EXACTLY THE SAME and the rocker is in a fixed position!
Second, if they were truly to long they would bottom out inside the lifter and HANG THE VALVES OPEN. Yes, this would be discovered long ago as they will pop and back when this condition exists.

Dave

Jeff@TotalPerformanceEng

iTrader: (6)

I GREATLY appreciate your advice. I just take offense to the sarcastic response. Rather than answering the question, you have to give me your "Role your eyes" one liners..

BUT, Thank you kindly for the info.

Phil, In regards to the lifter cups. What would cause these issues? Could they be the cups that had a slight angle to them? Would that cause the issues?

I will be pulling the heads tonight. I cant seem to get of wok long enough to actually pull them. I'll take a couple of pictures while their in te block and post them for you. Hopefully you can give me a little insight on the issues.

Thanks Bud,
Jeff

vettenuts

iTrader: (4)

With a non-adjustable rocker, the wipe pattern is fixed by the height of the fulcrum which in turn is fixed due to the bolt being tight. Changing pushrod length will alter the lifter preload, but will not affect the wipe pattern on the valve stem because it is fixed by the fulcrum. On a fully adjustable rocker such as the Cranes that I run, the pushrod length will determine both wipe and lifter preload.

Best best on re-assembly once your heads come back is to not buy any pushrods until things are back together again. Then use an adjustable pushrod to measure your pushrod length and from that length add the lifter preload.

Also, when you pull the lifters, look under the lifter trays and find out if you have any with a "10" on them, there were some issues with the "10" lifter trays. Since they were cheap, I replaced all mine and sure enough when I got it apart I had a "10".

Jeff@TotalPerformanceEng

iTrader: (6)

Thats great info to know..

2c5s

iTrader: (11)

LMFAO

HUNTER02SS

iTrader: (24)

I'm curious now. On my new motor with Dart haed's i installed the stock pushrod's and marked the top of the valve stem and with the stock rocker's on I turned the engine over by hand and it showed the wipe pattern over to one side and then when I got a longer pushrod it wiped the valve in the center where it is supposed to be.?? I do not understand how different pushrod lenght's don't change the wear pattern on the valve tip.It changed my wear pattern?
I read how to check pushrod lenght on this Forum!

HUNTER02SS

iTrader: (24)

So a shorter pushrod will push the rocker arm down only so far and then you change to a longer pushrod and it will push the rocker arm down the same distance on the valve tips within the operating range of the lifter.That do's not sound right to me.I am not a valvetrain expert by no mean's but when you add length to a pushrod it is going to push the rocker arm down futher into the valve.I thought that is why they made them in different lenght's.If not we could all just use the stock lenght pushrod's?IMOA!

stevieturbo

I think the key item here is You could install pushrods that may appear to work, but they could still fall outside the recommended tolerance specs of the lifter.

But if there is a mad head/valve/rocker geometry in the first place, altering pushrod length will nver cure that.

Unless its also in conjunction with lifting or raising the rocker platform itself as required.