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Attempt #2 Advice request

4K views 77 replies 25 participants last post by  ddawson 
#1 ·
Alright, so after my terrible experience with installing my cam i'm almost done doing it again, This time the right way.

The cam specs from comp



I took the heads off and went to the machine shop as I added some eyebrows to my pistons from being two teeth off advanced bending my intake valves

I also took the opportunity to port the heads, I didn't go too crazy but they look really good and I followed a bunch of advice here on the forums and many other sources. I didn't remove the rocker bolt hump but did most of the work in the bowl and valve guide area

I had them surfaced and new intake valves installed with some new used 1mm larger exhaust valves from an l92/ls3 and obviously a valve job with those.

They installed my springs (pac 1519 iirc) with some new retainers and viton valve seals from brian tooley racing

I installed some new lunati street link bar lifters and cleaned the surface of the block then installed the gaskets (stock gm) and torqued the new arp head bolts down to spec after wicking the oil/coolant from the holes and spraying carb cleaner and chasing the threads.

I then replaced all the trunion bearings with new comp cams bearings and used the comp cams pushrod length checker to determine the pushrod length


I got 7.325 pushrods as that is what I determined would give me the preload on the new lunati's that I wanted iirc they are going to be .040-.045
This part I am confident about as I did the math about 20 times

I also ordered new arp cam gear bolts and loctite and torqued them down after of course re-timing the cam at #1 tdc and aligning dot to dot.

Then I installed the new pushrods and torqued the rockers down to 22 ft lbs. and spun the motor over to check for interference.

As far as I can tell there is no ptv issue and it spins over nicely( wouldn't assume with this cam there would be any at all but I'm unsure of myself at this point) (sparkplugs removed and only one cylinder has the rockers installed) I watched the intake valve to check for any abrupt movement or bending then did the same for the exhaust. All feels and looks normal. The only clicking or noise I hear the the chain slack changing back and forth from sliding over the cam lobes (which i'm pretty sure is normal.)

And this is where I am right now. I would like to hear some advice on ptv clearance with this cam. As of right now I'm more worried about the exhaust side of the engine then the intake side as I have some newly added piston reliefs on the intake side and the timing is now correct. Giving me all the clearance I would need on that side I would think.
But now that the timing is dot to dot and I have bigger exhaust valves (not much) how close do you think they are?

They do not hit as confirmed with a mirror and a light while turning it over by hand and there is no resistance besides the pressure of the spring.

But as you can see I have reason to be a little worried/cautious as doing it a third time is really gonna set me back not to mention dent my moral a good bit.

I've done everything to the best of my knowledge and by myself(with lots of research) to be sure it is done correctly and double checked triple checked and id like someone to review my build that has a bit more knowledge on stock ls2 block clearances and cam duration lift and ptv experience before I put it back together and attempt a startup.

Thanks much!
 
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#2 ·
How about using a degree wheel to verify the cam is in fact installed correctly. Then after that is done you need to MEASURE for proper PTV clearance. That is the only real way to know. Or you could take the he said she said stuff and risk it... It's your car and your money do whatever you desire. Don't forget to measure for proper pushrod length or just guess at that too.
 
#3 ·
I could do that . I did measure for proper pushrod length using a comp cams pushrod measuring tool and following a method I found on these forums as stated above.

Not looking for he said she said just looking for someone that knows measurements and clearance
 
#4 ·
Valvetrain Tech Notes #1 --- "Dot to Dot"


“I installed it dot to dot.”

This is one of the most popular comments I hear after less than ideal results are seen when a camshaft installation is completed. Just the mentioning of this sends chills down my spine.

The proper installation of a camshaft and its peripheral valvetrain is one of the most important jobs an installer must do when maximizing the performance of any engine combination. Any short cuts or miscues in this regard, and the overall success of the project, and its ultimate performance, will definitely suffer.

How can something so simple be so problematic?

Let’s start with the basic premise that everyone can have a bad day at work. Who’s to say the crankshaft keyway was machined absolutely “dead on” when the machinist set it up? I mean, even a slight error of a degree or two is no big deal considering the thousands and thousands of engines out in the world. They run, don't they? Maybe it wasn’t even a bad day but something that is machined off the mean number but still within manufacturing tolerances. What's a degree or two among friends?

Now we have the next piece of the tolerance puzzle, the timing set. There are a series of variables that can occur with this component. The relationship of the keyway to the crankshaft sprocket teeth, the location of the cam dowel hole to the cam sprocket teeth and then there’s always the possibility of “both” items being off. Why worry? Well, if each facet is off in the same direction, it is a cumulative error that will change the engine's dynamics. That's why verifying the intake centerline as it relates to top dead center is very important.

When you're installing these two pieces to the engine, who’s to say they are so perfect, there’s no reason to check them?

Nothing is further from the truth. You'll never hear a professional engine builder say this. At least not one that knows the hows and whys of valvetrain importance. This is the type of attention to detail that separates the engine assemblers from the engine builders.

No camshaft should be just installed “dot to dot” if the installer is a professional!

Now the novice or the weekend mechanic might be able to justify doing a camshaft installation in this manner just because the tools required are not something a newbie has put the investment in. It's "almost" forgivable when this is spoken. However, when I hear his “dot to dot” comment from a shop that just charged a customer a lot of money to do the install, well, it definitely crosses the line and takes them off the referral list.

Take your time and verify everything. If you don't have the time, tools or talent to do it yourself, find a professional to do it for you. It's worth the effort!
 
#5 ·
Feel free to say I told you so when I'm back on here with bent valves.
But even if I were to degree it thats not going to help me with ptv clearance other than to tell me where and which valve is doing it. I would just be out the price of the tools to do it still needing more clearance. Or am I totally off base.
 
#8 ·
Ignoring the comments meant to apparently make me angry or something of the sort some of you are actually being helpful.

Even if I were to degree the cam what am I supposed to degree it too?

The way I see it no matter the degree idk if this cam will have ptv issues or not.
be it 4* advance built in or not

AFAIK a degree wheel will not make a cam fit unless I know which way to advance or retard it, so what am I supposed to do besides verify it is or isn't off from the specs on the cam card. As changing it won't really help me know if it's clearing or not.
 
#9 ·
Also since I can't change the timing with a stock gearset and I can't regrind the cam as that is well you know.
What good is degreeing a cam that I can't change going to do for me other than piss me off?

I wanted to know ptv clearance not how to degree a cam. which as I understand could help me fix a ptv issue but if I don't have one I don't need to do that. obviously you guys can't help me with a ptv clearance calculation so guess I need no help. :scratch:
 
#11 ·
^^ like really? stay out and help instead of being an ass. No wonder everytime i see a fellow gto owner on the road it's some dick that thinks his shit don't stink.

You guys make me want to :barf:

So your saying you do know it will have ptv problems

I don't think you fully understood what I was saying.

If the cam is in fact ground properly it will have 4 degrees advance built into it which could be verified by degreeing the cam.
That in no way helps me identify a ptv issue only that the cam is accurately timed to the crank. And that the cam is properly ground as per the cam sheet specs.

So my statement stands Idk if degreeing the cam any differently than what it is right now will cause more issue or not.

I do know that if I advance it too much (like two teeth on the cam gear) it will hit the piston on the intake side. that much is obvious So If I were to do anything after degreeing it no matter what it said i would have to retard the timing further not advance.
 
#27 ·
^^

I don't think you fully understood what I was saying.

If the cam is in fact ground properly it will have 4 degrees advance built into it which could be verified by degreeing the cam.
That in no way helps me identify a ptv issue only that the cam is accurately timed to the crank. And that the cam is properly ground as per the cam sheet specs.

So my statement stands Idk if degreeing the cam any differently than what it is right now will cause more issue or not.

I do know that if I advance it too much (like two teeth on the cam gear) it will hit the piston on the intake side. that much is obvious So If I were to do anything after degreeing it no matter what it said i would have to retard the timing further not advance.
This is why I posted that link. You seem to be having issues with how to degree a cam and check PTV. If the cam doesn't degree in, get a timing set that will let you set it. If the PTV is off, fly cut.
 
#13 ·
Ya know, I don't know jack shit about how to install a cam. But I know enough to know that I don't know what I'm doing. My solution would be to pay someone, or find a gearhead buddy to help me with it.

I sure as hell wouldn't come on the forums and ask for help, then get pissed when people give you suggestions. Get the sand out of your vagina and quit being a little bitch.
 
#18 ·
YMy solution would be to pay someone, or find a gearhead buddy to help me with it.
I tried that and that's why its f'ed up right now. I started out helping my dad restore his cars when I was 9 then I went to work for him restoring corvettes
Then I changed tires and did things like brakes and alignments at a tire shop while in highschool, I decided I wanted better so I went out looking for an education.
So I went to wyotech and took the automotive course and then took the chassis fabrication class. I can build a rearend backhalf a car or build the whole frame, I've made and installed roll bars and rebuilt transmissions engines and modified multiple vehicles of my own however i see fit. And Iv'e had several.
I then got a job at a chevrolet dealer started out changing oil then I moved into R&R of whatever was broken be it sunroofs power steering pumps or entire engines and transmissions. I decided that wasn't for me ((screwing people over))

So I started my own dealership and I repair every single car that I sell in some way be it the engine or just a window motor. I've rebuilt several cars including my gto that I got at an auction wrecked. I have all the tools and diagnostic equipment I could ever need. Shit the dealership I worked at was always borrowing my ethos for diagnosing other cars they would get in and their tech 2's couldn't read.

So I think I'm more than qualified to put a cam in a simple ls engine


If you don't want the possibility of this happening again take the advise of others that have more knowledge than you do, its not a knock on your ability just advise to help you do a better job without the extra money and time spent doing it again. I can understand making the mistake once, hey we've all done that, but twice would be stupid. Heed their advice, a little extra money spent now on the tools to do it correctly well give you the opportunity to gain some much needed knowledge on your valvetrain. Hope you get it sorted out to your satisfaction. Do it the right way.

Kevin
Again the first time it wasn't my fault My buddy dropped the chain and didn't say anything, I hardly think thats my fault. Besides I should have pulled the heads and replaced the lifters the first time after looking at them this time around they were due up.

So basically you're the type of guy that complains that his roof is leaking all the while building your house on a sink hole? Have you heard of rearranging the deck chairs on the titanic analogy?

Listen Mr. Thinskin - the FIRST thing you do is to verify the fking cam is in the proper phasing to the reciprocating assembly. Otherwise known as degreeing the camshaft.

THEN you check the piston to valve clearance.

Now - if you don't know why this must be done first, you should sell the damned car and take up another hobby.

:banghead:

/going back to Yellowbullet to calm down
Even ed is being unnecessarily negative and accusing me of being stupid.
I've built houses and roofed them several times.

I have thinskin because you guys have a tendancy to make unnecesarilly stupid comments just trolling.
Obviously not buying anything from you or recommending you if you have an attitude like that. I can't imagine how you would have handled it if it was your cam and your heads I was installing...

And for the last comment you really are not helping anything saying that as I really have no way of changing my career at this point since I fix and repair cars on a daily basis.

Otherwise thanks for the first post you made it was actually helpful.

OP you wanted advice, you got it from EDC. If you already screwed it up once I would think you would want to listen to an expert the second go around. Do it right the first...ermmm second time.
Again I didn't screw it up the first time... So here I am trying to do it right simply asking why it would be necessary to degree something I cannot change with the stock timing set that I don't plan on removing.

So anyone else have something negative to say you might as well get it out now so I can ask questions
 
#14 ·
Alright, so after my terrible experience with installing my cam i'm almost done doing it again, This time the right way.

Thanks much!
If you don't want the possibility of this happening again take the advise of others that have more knowledge than you do, its not a knock on your ability just advise to help you do a better job without the extra money and time spent doing it again. I can understand making the mistake once, hey we've all done that, but twice would be stupid. Heed their advice, a little extra money spent now on the tools to do it correctly well give you the opportunity to gain some much needed knowledge on your valvetrain. Hope you get it sorted out to your satisfaction. Do it the right way.

Kevin
 
#15 ·
So basically you're the type of guy that complains that his roof is leaking all the while building your house on a sink hole? Have you heard of rearranging the deck chairs on the titanic analogy?

Listen Mr. Thinskin - the FIRST thing you do is to verify the fking cam is in the proper phasing to the reciprocating assembly. Otherwise known as degreeing the camshaft.

THEN you check the piston to valve clearance.

Now - if you don't know why this must be done first, you should sell the damned car and take up another hobby.

:banghead:

/going back to Yellowbullet to calm down
 
#24 ·
#25 ·
There is nothing in that link that's not been said on this thread.

I really don't understand the comments made in this thread.

And still none of the questions I've asked have been answered

Only negative thrashes against anything I say.
 
#31 ·
But how will you know. You'e not going to get anyone reputable to tell you absolutely that the PTV is ok.

Measure it and see, then you'll know. Line it up dot to dot if you want, then check it.
 
#33 ·
The link I gave you is full of info. Using checker springs and dial indicator is how I do it. Kinda tricky swapping the spring leaving the head on tho.
 
#34 ·
Ya i know theres really no good way to do it at this point.
When I installed the springs the first time I just shoved a bit of spark plug wire I had around in there to hold the valve up and spun the motor till it stopped and that worked quite well.

I guess I will do that and install a checker spring to keep the lifter from bleeding down so fast. which is the issue i'm having just spinning it over by hand. it bleeds off quick and i can see the valve suck back in.

Although if im thinking correctly the point of contact would be within the first bit of down and up travel depending on the valve im working with.
 
#35 ·
There are adapters that go in the spark plug hole that allows you to hook an air compressor up and pressurize the cylinder.
 
#36 ·
Ya I know I can use my compression tester and remove the valve but I don't trust air as all it takes is for me to bump into it opening it for a split second and then it drops... the valve that is

And with air pressure the piston only really likes being at the bottom of its stroke potentially ruining the idea of not removing the head
 
#38 ·
I'm out , good luck.
 
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