MS4 clearance issues...
ptvc Hi bjamick,
Just to cure definitively this suspicion about the reasons why your valves hit your pistons heads, the most simply possible give us your Piston to Valve Clereance at the end of your camshaft installation please.
Can't imagine you don't know (because you didn't measure) if you have a 0.040 or a 0.090 of clereance on the intake side...that would not be reasonnable, I think!!!
Waiting to read from you your measurements
Christian
Just to cure definitively this suspicion about the reasons why your valves hit your pistons heads, the most simply possible give us your Piston to Valve Clereance at the end of your camshaft installation please.
Can't imagine you don't know (because you didn't measure) if you have a 0.040 or a 0.090 of clereance on the intake side...that would not be reasonnable, I think!!!
Waiting to read from you your measurements
Christian
It has zero ,nothing to do with ptvc. well it will i guess when the piston come's out of the hole so far that it hit's the damn head. i guess yeah it was a piston to head and a ptvc problem.L.O.L
ms4 Hi bjamick,
In the country of freedom I will let you responsable of your own actions....
The technical facts are that with all the dispertions in the numerous parts forming the chain of parts from cranck to valves related to the industry building process of those you can't be sure of how much are your pistons out of the hole.
The 0.007 out of the hole from the factory is an average measurement and can be from 0.004 to 0.12!!!!that I have seen.
I had camshafts from Comp cam doctored and again the regular dispersition due to machining can lead your measurements to be a little off the advertised numbers.
A degreeing of the camshaft is highly recommended to be in line with the numbers of the camshaft designer...
As a consequence of your complete processing (or lack of process) you don't know your PtV Clereance...at all.
No measurements at this level and all your comments are just guesses, and as an hypothesis I will say your intakes valves were kissing the piston's heads in cylinder one and six, and repeated hammering damaged the bearing con rod.
Just a guess....with no value, or the same value that your statements.
On the other hand, congrat for this job about modifying your engine, just take care than your passion doesn't darken the reality...
Christian
In the country of freedom I will let you responsable of your own actions....
The technical facts are that with all the dispertions in the numerous parts forming the chain of parts from cranck to valves related to the industry building process of those you can't be sure of how much are your pistons out of the hole.
The 0.007 out of the hole from the factory is an average measurement and can be from 0.004 to 0.12!!!!that I have seen.
I had camshafts from Comp cam doctored and again the regular dispersition due to machining can lead your measurements to be a little off the advertised numbers.
A degreeing of the camshaft is highly recommended to be in line with the numbers of the camshaft designer...
As a consequence of your complete processing (or lack of process) you don't know your PtV Clereance...at all.
No measurements at this level and all your comments are just guesses, and as an hypothesis I will say your intakes valves were kissing the piston's heads in cylinder one and six, and repeated hammering damaged the bearing con rod.
Just a guess....with no value, or the same value that your statements.
On the other hand, congrat for this job about modifying your engine, just take care than your passion doesn't darken the reality...
Christian
so let me get this right. you are saying the cam is ground so uneven that just 1&6 had ptvc problems.
funny is all i can say.nothing further
but i am still laughing
We just covered (meaining all of us, the kid with the car, the people on this thread, and even a sponser from TSP) that this had nothing to do with the cam. looks like a bucket of *** blew up all over some girl scouts in here! Just kidding, but I mean really....the machining and QA of most of this stuff is incredible these days, right? Ask anyone who is taking their time and technically hardcore, they are going to doctor and take good measurements, true. usually they are doing this for personal piece of mind....which is what you want.
Fortunately bjamick who was concerned by my post # 10 answered clearly to it...
Last edited by miami993c297; Dec 11, 2007 at 11:14 PM.
Please reread my post # 13, nothing written about uneven work quality on the camshaft.
Do you know the PtV Clereance on your build engine?
BTW, never stop laughing and always have fun.
Christian
well, i did have PTV clearance problems in my motor. i installed the cam, and i already has crane duals on the car, so i left them on. everything was fine, got the car tuned and found out my injectors were too small blah blah.... and raced the car several times with zero problems. then one day it started to tick, and wouldn't rev over 5k. took off the heads, and found 9 random broken valve springs. and i have 4 valves touch and leave marks in the pistons. not good, so i just put on the PRC springs that came with the kit, and threw the heads back on. 2 days later made 404whp on the dyno, and out ran another heads and cam 6 speed car... that was running 11.50's at 121.
it was my fault things happend like this, but the point is, the valve kit cuz the springs were broke.
thats my story with the MS4, and i wouldn't trade it for any other cam for stock heads and bottom end.
Charlie
it was my fault things happend like this, but the point is, the valve kit cuz the springs were broke.
thats my story with the MS4, and i wouldn't trade it for any other cam for stock heads and bottom end.
Charlie
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You might be able to pull the wool over the eyes of a lot of people here with statements like that, but please don't assume everyone here doesn't know a thing or two.
What a joke, drawing comparisons between a cam that barely fits like the ms4 vs a stock cam, when talking about ptv on an over-rev. Are you trying to make it sound like your big cam will clear like a stock cam?
You might be able to pull the wool over the eyes of a lot of people here with statements like that, but please don't assume everyone here doesn't know a thing or two.
You might be able to pull the wool over the eyes of a lot of people here with statements like that, but please don't assume everyone here doesn't know a thing or two.
that is not what he was trying to get at....
I think what he ment was an over rev could cause valve float, which if bad enough could cause piston to valve contact. i had this problem, but was because of broken vavle springs...
or maybe i'm wrong.
Charlie
I don't think it really should be referred to as "over rev" but rather loss of valve control. You can rev to extreme RPM's with the correct components, but when you lose control of the valve events you run into problems. I agree with some of the above, a lot of guys don't check PTV, don't check rocker wipe, don't measure spring installed height or use valve spring shims for adjustment of valve spring values, etc. etc. etc. Many bolt on the parts and go, which is fine since there are a lot of guys here who are on budgets and having fun with their cars, but there are inherent risks in this approach and as the cam profiles and components become more extreme (big cam vs. small cam for example) the risks go up. There are minimum recommended values for PTV for a hydraulic valve train, and from the above post by TSP it sounds like this particular cam is under those values ("We see an average of .060" PTV clearance on the intake with MS4 cams.") . So again, more risk. There is a way to mitigate the risk, flycut the pistons to the minimum recommended values of PTV. If you don't measure you don't know.
The other thing that is discussed a lot in this thread are piston out of the hole values and a host of static measurements. We are talking dynamics here and no one is accounting for rod stretch, thermal block/head movement, lifter pump-up, etc. On the flip side, rocker bending and pushrod flex lower the actual valve lift so these events will counteract the rod stretch, etc. to some degree. The minimum recommended values try and include a safety factor that includes these phenomena.
The other thing that is discussed a lot in this thread are piston out of the hole values and a host of static measurements. We are talking dynamics here and no one is accounting for rod stretch, thermal block/head movement, lifter pump-up, etc. On the flip side, rocker bending and pushrod flex lower the actual valve lift so these events will counteract the rod stretch, etc. to some degree. The minimum recommended values try and include a safety factor that includes these phenomena.
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From: BFE
I don't think it really should be referred to as "over rev" but rather loss of valve control. You can rev to extreme RPM's with the correct components, but when you lose control of the valve events you run into problems. I agree with some of the above, a lot of guys don't check PTV, don't check rocker wipe, don't measure spring installed height or use valve spring shims for adjustment of valve spring values, etc. etc. etc. Many bolt on the parts and go, which is fine since there are a lot of guys here who are on budgets and having fun with their cars, but there are inherent risks in this approach and as the cam profiles and components become more extreme (big cam vs. small cam for example) the risks go up. There are minimum recommended values for PTV for a hydraulic valve train, and from the above post by TSP it sounds like this particular cam is under those values ("We see an average of .060" PTV clearance on the intake with MS4 cams.") . So again, more risk. There is a way to mitigate the risk, flycut the pistons to the minimum recommended values of PTV. If you don't measure you don't know.
The other thing that is discussed a lot in this thread are piston out of the hole values and a host of static measurements. We are talking dynamics here and no one is accounting for rod stretch, thermal block/head movement, lifter pump-up, etc. On the flip side, rocker bending and pushrod flex lower the actual valve lift so these events will counteract the rod stretch, etc. to some degree. The minimum recommended values try and include a safety factor that includes these phenomena.
The other thing that is discussed a lot in this thread are piston out of the hole values and a host of static measurements. We are talking dynamics here and no one is accounting for rod stretch, thermal block/head movement, lifter pump-up, etc. On the flip side, rocker bending and pushrod flex lower the actual valve lift so these events will counteract the rod stretch, etc. to some degree. The minimum recommended values try and include a safety factor that includes these phenomena.
The poeple who actualy understand the logistics and dynamics of a motor would never fall for "yes it will clear" and actually go through the plathera of measurements and blueprinting procedures to do it right.
I applaude vendors (whether sponsors or not) for at least giving a fair warning to their clients by advising "it is recomended to check PTVC with XXX cam"
I also find it misleading just to confirm that XXX cam WILL clear with safe margins by just "installing it right (dot-to-dot)". IMO in their fear of maximising revenue, they completely give false info (funny our government does the same LOL).
I believe it is the right of every consumer to know the truth (in writing) and make his/her/it's decision.
I have cam doctors for 4 different MS4 and 3 different TREX all on same specs but none are exactly alike. Point being, no two motors are alike, no two cams are alike (unless ground on same machine on same day by same tech with same calibration <and still they may variate>)
I've seen as much as 2* variation on specs (acceptable margin as per Comp Cam policies) and a those durations and VEs, that could be disastrous.
No one here is bashing any vendor or cam, merely we are trying to educate our fellow Techers that there is the right way and the sloppy way to do things.
->Cam should be doctored
->Cam should be degreed
->Valvetrain should be compatible with cam spec requirements.
->PTVC should be measured
->Preload should be measured
->Geometry sould be correct
Last edited by PREDATOR-Z; Dec 12, 2007 at 12:02 PM.
What a joke, drawing comparisons between a cam that barely fits like the ms4 vs a stock cam, when talking about ptv on an over-rev. Are you trying to make it sound like your big cam will clear like a stock cam?
You might be able to pull the wool over the eyes of a lot of people here with statements like that, but please don't assume everyone here doesn't know a thing or two.
You might be able to pull the wool over the eyes of a lot of people here with statements like that, but please don't assume everyone here doesn't know a thing or two.
We never try to hide anything from customers. We always expect customers to confirm our numbers all the time. The MS4 cam has been out for almost 2 years now. If there was a problem with the camshaft or we were lying about our numbers, clearances, ect., I think we would have seen it with the 1,000+ other cams we have running in customer's cars...
Last edited by Jon@Texas-Speed; Dec 12, 2007 at 11:54 AM.
