Re: measuring for pushrods with hydraulic lifters
[Re: MR_P_BODY]
#967179
04/08/11 07:23 PM
04/08/11 07:23 PM
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The engine is an LA with a bone stock bottom end...
I got the pushrods all measured up today, but ran into bigger issues...the intake valve on the heads is deep into the piston, so it looks like im going to be making a piston fly cut tool with the old heads and putting notches into the stock pistons...kinda worried though as to how thick these pistons are
First... what is the cam installed at and what is the LSA.... as to the geometry of the rockers... the push rod dosent change that... you need to raise or lower the rocker shaft to do that
the cam is a 106 LSA installed straight up on a 101 intake centerline
I wasnt referring to the geometry of the rockers. My intake valves are hitting the piston big time when I turn the motor over to check piston to valve. So much so that the valve is cutting into the piston and vice versa. I checked the exhaust valve the same way and its fine...im thinking the combination of the larger intake valve than stock (2.02 vs. 1.88) and the high lift on the cam with small 62cc chambers in the heads and the lack of valve reliefs in factory pistons is what culminated in this.
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Re: measuring for pushrods with hydraulic lifters
[Re: Stanton]
#967180
04/08/11 07:26 PM
04/08/11 07:26 PM
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1) You said you checked the geometry and its ok, right?
2) You said you don't have checker springs and you're using hydraulic lifters. So, how have you determined the intake valve "is deep" in the piston? Are you checking this with the cam installed where you want it and turning the motor over by hand with clay in the piston?
"deep" means squat ... its the actual piston to valve clearance through a normal cycle that matters.
Yes the cam is installed where I want it. Im using a lifter that I shimmed up inside so that it acts like a hydraulic lifter with about .080" of preload. The pushrod length part and rocker geometry is fine
What I meant by the valve being deep into the piston is that when I am checking with clay for piston to valve and turning the engine over, the intake valve is actually cutting into the piston
I should have been more specific...i used to the word deep instead of "cutting in" to make myself feel better in my head...I was hoping today to bolt the heads on, but its a darn good thing i checked for this...atleast im learning everything about engine building now lol
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Re: measuring for pushrods with hydraulic lifters
[Re: MR_P_BODY]
#967182
04/08/11 08:11 PM
04/08/11 08:11 PM
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the cam is a 106 LSA installed straight up on a 101 intake centerline
I wasnt referring to the geometry of the rockers. My intake valves are hitting the piston big time when I turn the motor over to check piston to valve. So much so that the valve is cutting into the piston and vice versa. I checked the exhaust valve the same way and its fine...im thinking the combination of the larger intake valve than stock (2.02 vs. 1.88) and the high lift on the cam with small 62cc chambers in the heads and the lack of valve reliefs in factory pistons is what culminated in this.
Your cam is not straight up... you have it installed 5* advanced... still shouldnt be hitting.... have you measured yet how much its crashing... why dont you give use all the specs on the cam and the pistons... also did you check the balancer when you installed the cam
the cam has 5 degrees advance ground into it which is why 101 is straight up (This is what I was told before having the cam ground). The balancer is not on the engine yet, I degreed the cam with the heads off and the balancer off using the intake centerline method and the intake/exhaust open/close method as well.
As far as piston specs go, I really don't have any on them. They are stock 91 LA pistons that came with the motor, factory dished, with no valve releifs. I would say the dish is anywhere from 5-7cc as its not very deep. The chambers on the heads are 62cc
The cam specs are for installed at 101 intake centerline Duration at .50"- 230/230 Lobe lift (at the valve with 1.6 rockers)- 577/569 Lobe seperation- 106 valve timing at .050 open close Int: 14 BTDC 36 ABDC Exh: 46 BBDC 4 ATDC
what do you think?
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Re: measuring for pushrods with hydraulic lifters
[Re: mshred]
#967183
04/08/11 08:20 PM
04/08/11 08:20 PM
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the cam has 5 degrees advance ground into it which is why 101 is straight up (This is what I was told before having the cam ground). The balancer is not on the engine yet, I degreed the cam with the heads off and the balancer off using the intake centerline method and the intake/exhaust open/close method as well. As far as piston specs go, I really don't have any on them. They are stock 91 LA pistons that came with the motor, factory dished, with no valve releifs. I would say the dish is anywhere from 5-7cc as its not very deep. The chambers on the heads are 62cc The cam specs are for installed at 101 intake centerline Duration at .50"- 230/230 Lobe lift (at the valve with 1.6 rockers)- 577/569 Lobe seperation- 106 valve timing at .050 open close Int: 14 BTDC 36 ABDC Exh: 46 BBDC 4 ATDC what do you think?
Its still 5* advanced... maybe you are referring to what they wanted it installed at(101)... without the balancer on the engine how did you reference the crank... I think you have the cam in wrong... that cam and those pistons shouldnt hit
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Re: measuring for pushrods with hydraulic lifters
[Re: MR_P_BODY]
#967184
04/08/11 08:31 PM
04/08/11 08:31 PM
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the cam has 5 degrees advance ground into it which is why 101 is straight up (This is what I was told before having the cam ground). The balancer is not on the engine yet, I degreed the cam with the heads off and the balancer off using the intake centerline method and the intake/exhaust open/close method as well.
As far as piston specs go, I really don't have any on them. They are stock 91 LA pistons that came with the motor, factory dished, with no valve releifs. I would say the dish is anywhere from 5-7cc as its not very deep. The chambers on the heads are 62cc
The cam specs are for installed at 101 intake centerline Duration at .50"- 230/230 Lobe lift (at the valve with 1.6 rockers)- 577/569 Lobe seperation- 106 valve timing at .050 open close Int: 14 BTDC 36 ABDC Exh: 46 BBDC 4 ATDC
what do you think?
Its still 5* advanced... maybe you are referring to what they wanted it installed at(101)... without the balancer on the engine how did you reference the crank... I think you have the cam in wrong... that cam and those pistons shouldnt hit
so if i retard the cam then I would gain piston to valve clearance? how does that work? What effects on performance would retarding the cam have, and would retarding it 5 degrees help me gain the clearance i need?
I lined up the timing gear marks for straight up on the timing set and found top dead center with a dial indicator on #1 piston as outlined in all the instructions i have ever found i.e. hughes engines, comp cams, my mopar hotrodding book. According to all my calculations and where this cam is supposed to be installed (Straight up at 101) the timing gear and my install are correct.
Please don't take this as me being sure...I am doing all of this for my first time and am still learning. I would really rather not flycut the pistons, but im not sure what else to do...I don't want to compromise performance in an already low compression motor by retarding the cam
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Re: measuring for pushrods with hydraulic lifters
[Re: mshred]
#967185
04/08/11 08:42 PM
04/08/11 08:42 PM
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so if i retard the cam then I would gain piston to valve clearance? how does that work? What effects on performance would retarding the cam have, and would retarding it 5 degrees help me gain the clearance i need? I lined up the timing gear marks for straight up on the timing set and found top dead center with a dial indicator on #1 piston as outlined in all the instructions i have ever found i.e. hughes engines, comp cams, my mopar hotrodding book. According to all my calculations and where this cam is supposed to be installed (Straight up at 101) the timing gear and my install are correct. Please don't take this as me being sure...I am doing all of this for my first time and am still learning. I would really rather not flycut the pistons, but im not sure what else to do...I don't want to compromise performance in an already low compression motor by retarding the cam
First off you really dont know where its installed at... get a degree wheel on it... forget about the dots they can be way off... just because you lined up the dots doesnt mean its straight up... you are at 5* advanced from something... when the intake is at full lift the crank (degree wheel) will say 106*, thats straight up..... yes when you advance/retart the cam it changes the valve to piston clearance... you should get a buddy over to help you install it and show you how.... I wonder if you used the exhaust valve instead of the intake EDIT did you clay the piston just to make sure it isnt hitting the lip of the piston... just checking
Last edited by MR_P_BODY; 04/08/11 08:52 PM.
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Re: measuring for pushrods with hydraulic lifters
[Re: MR_P_BODY]
#967186
04/08/11 09:00 PM
04/08/11 09:00 PM
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Quote:
so if i retard the cam then I would gain piston to valve clearance? how does that work? What effects on performance would retarding the cam have, and would retarding it 5 degrees help me gain the clearance i need?
I lined up the timing gear marks for straight up on the timing set and found top dead center with a dial indicator on #1 piston as outlined in all the instructions i have ever found i.e. hughes engines, comp cams, my mopar hotrodding book. According to all my calculations and where this cam is supposed to be installed (Straight up at 101) the timing gear and my install are correct.
Please don't take this as me being sure...I am doing all of this for my first time and am still learning. I would really rather not flycut the pistons, but im not sure what else to do...I don't want to compromise performance in an already low compression motor by retarding the cam
First off you really dont know where its installed at... get a degree wheel on it... forget about the dots they can be way off... just because you lined up the dots doesnt mean its straight up... you are at 5* advanced from something... when the intake is at full lift the crank (degree wheel) will say 106*, thats straight up..... yes when you advance/retart the cam it changes the valve to piston clearance... you should get a buddy over to help you install it and show you how.... I wonder if you used the exhaust valve instead of the intake EDIT did you clay the piston just to make sure it isnt hitting the lip of the piston... just checking
I used a degree wheel man...i have followed the instructions to a T...and no, I measured the intake, not the exhaust valve. I know the difference between the two...I said im still learning, not that im stupid lol
Im gonna talk to Brian about this since he did my cam and heads and see what he thinks about retarding these cam specs on my motor...id much rather do that then flycut the pistons
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Re: measuring for pushrods with hydraulic lifters
[Re: mshred]
#967189
04/09/11 10:21 AM
04/09/11 10:21 AM
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Hey Mr. P., sorry if i came across like an ass last night, was just a bit flustered with the whole situation and some other stuff that has just put me in a not so good mood lately...everything you asked and stated was valid, and I appreciate you trying to help me out. I think I have this figured out now and I will post up my results as soon as I get them Going to retard the cam so that its installed straight up on and see what happens
thank you
No biggie... get some clay and see if the valve is hitting the edge of the piston
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Re: measuring for pushrods with hydraulic lifters
[Re: MR_P_BODY]
#967190
04/10/11 03:08 PM
04/10/11 03:08 PM
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well I have since done this... retarded the cam using the 4 degree key way on my Cloyes True Street roller timing set and degreed the cam as well...Cam actually retarded all the way from 101 ICL to a 108ICL, so 7 degrees, which is two degrees retarded past straight up (So much for the accuracy of the keyways). At this point I figure heck, i'll have miles of PTV clearance. I have been checking PTV with one of my hydr. lifters shimmed up to have .080" preload, and readjusted pushrod length for best geometry and maximum lift. I checked PTV with 0.036" shims to simulate an in between of the two gaskets I have available (0.028" compressed or .050" compressed). My findings were less than stellar... Even after all that retarding, the exh. PTV was .150", while int. PTV was at best .065"..however, my problem is that I am using a dial indicator on the retainer to assure im getting max lift when checking PTV, but max lift keeps changing anywhere from 549-555" on the int...im assuming this is because the needle will never be perfect on the retainer, but it is fudging up my readings on the clay- there seems to be lots of clearance within the dish, but where the dish raises up to the flat part of the piston is where its close...some of my clay readings were around .030" still! Its all over the place! My plan is to call Brian and discuss my options with him, and also to pick up a checking spring from the hardware store and try a little bit of a different method to check PTV...at this point im starting to get flustered as im not sure what else to do- i really dont want to cut the stock cast pistons just a few specs for thought...my heads are 62cc, cam is 577int/ 569" exh lift according to the cam card using Hughes 1.6 rockers, pistons are below deck about .083", dish has no valve releifs and is in the 5-7cc area, with stock bore and stroke for a 360 (4.00 x 3.58). Im learning alot through all this...im also getting large headaches lol
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Re: measuring for pushrods with hydraulic lifters
[Re: Stanton]
#967192
04/10/11 03:47 PM
04/10/11 03:47 PM
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Rocker shafts are loose or flexing causing the variance in lift. Possibly even the indiator arms are moving slightly (not uncommon).
Also, .080 is too much preload on the lifter, it should only be something like .010 to .025 (I believe). Personally, if it were me, I'd be setting things up with ZERO preload and allowing that as a safety buffer when things finally go together.
You have a head gasket in there, right? What's your calculated compression right now? What will it be if you increase the head gasket thickness to gain PV clearance? If that's even an option!!
I will check the tightness of the rockers. They are tight when i put them on, but i will double check them.
I set the lifters to .080" preload as thats what Hughes Engines said when I called and talked to Kevin. Im using Hydraulic roller lifters, not flat tappet, so thats where the difference is. He told me I won't gain anything going lower than that, all that I will get is more noise. Im also doing all these checks with zero lash
I don't have a head gasket in when I am checking this. I have been using .036" shims since I kinda didnt want to use up a set of gaskets, but i think im just going to bite the bullet and use a set...however, at this point im also not sure which set i will use- I have a set of the mopar .028" thin gaskets to get compression up (this is a bone stock bottom end so i could use all the CR boost I can get) and the felpro 8553 permatorques which are around .050" compressed from what others have said
calculating with the my current head combo, bore, stroke, 0.083 deck clearance, 5-7cc dish on the pistons, and .028" head gasket thickness, im looking at about 9.1:1 CR....Id really rather not go to the thicker gasket since I will be around 8.8:1, but I will if I have to
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Re: measuring for pushrods with hydraulic lifters
[Re: mshred]
#967193
04/10/11 03:54 PM
04/10/11 03:54 PM
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Use your thin head gasket but just snug it to about 40-50 LBS that way you can still use them... try not to retard the cam, with your low comp and late valve closing it would make it a MUTT
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Re: measuring for pushrods with hydraulic lifters
[Re: MR_P_BODY]
#967194
04/10/11 03:57 PM
04/10/11 03:57 PM
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Use your thin head gasket but just snug it to about 40-50 LBS that way you can still use them... try not to retard the cam, with your low comp and late valve closing it would make it a MUTT
But Mr. P, I was getting insane valve to piston smack before. Still think I should try with the gasket and installing the cam back at 101 (where the 5 degrees advance were ground in). If i try it here again and im still getting PTV contact, what is the issue and what is the fix?
I was worried about retarding the cam so much as well in terms of the effects on performance like you mentioned, but figured it was my only option
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Re: measuring for pushrods with hydraulic lifters
[Re: Stanton]
#967195
04/10/11 05:29 PM
04/10/11 05:29 PM
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Im also doing all these checks with zero lash
I should hope so! Tell me how you would preload a lifter .080 and then put in lash ?!?!?!
I gotta believe that anything you read regarding checking PV clearance told you to mock things up as you would run it ... INCLUDING HEAD GASKETS. Get 'em in there, you've been wasting your time without them.
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Re: measuring for pushrods with hydraulic lifters
[Re: Stanton]
#967196
04/10/11 08:18 PM
04/10/11 08:18 PM
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Quote:
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Im also doing all these checks with zero lash
I should hope so! Tell me how you would preload a lifter .080 and then put in lash ?!?!?!
I gotta believe that anything you read regarding checking PV clearance told you to mock things up as you would run it ... INCLUDING HEAD GASKETS. Get 'em in there, you've been wasting your time without them.
your probably right, and yes, I will be checking with the gaskets next time I get at it.
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