Interesting cam problem
- Thread starter A2000RICH
- Start date
ITSAV6
It's my Granny's car!
- Joined
- Nov 13, 2001
X2 or maybe a link bar issue? It's probably something really crazy being Richard posted it like this, wants us to use lotsa gray matter
- Joined
- May 28, 2001
Lifter bores off location?
imjoesnuffy
I just break stuff!
- Joined
- Sep 13, 2005
larrym
West Coast Newfy
- Joined
- Jul 17, 2007
Would they not all be shifted in the same direction?
- Joined
- May 26, 2001
I would send the cam back to the manufacturer.
In the early days of ductile roller cams we had a couple from Comp which had the lobes offset enough the lifter would contact the adjacent lobe?
We just removed a "new" cam [not Comp] that was ground 50 degrees off center, and you can imagine how bad the GN performed.
In the early days of ductile roller cams we had a couple from Comp which had the lobes offset enough the lifter would contact the adjacent lobe?
We just removed a "new" cam [not Comp] that was ground 50 degrees off center, and you can imagine how bad the GN performed.
haywire4130
Active Member
- Joined
- Sep 11, 2010
Could it be thats a flat tappet cam used with roller lifters? Its my understanding flat tappets are ground slightly crooked to make the lifters spin in the bores?
I decided to post these pics today since i figured that after 4 cams in the last couple months with a serious problem i could not expect that i could be the only person that might experience this. I have been building quite a few engines lately and out of the last several engines that have had cast roller cams this problem has plagued 4 of them. This problem has not surfaced on flat tappet cams or billet roller cams that i have put in any engines. These cams have come from different dealers and all of them have been Comp. When the first one surfaced i immediately thought it must be the block. I checked the block ( i have original blueprints of the 109 block to go by) and found the lifter bores to be within a few thousands. First time i had the problem i was setting lifter preload with rocker arm adjustments and noticed that the valve actuation was erratic. After checking I saw that some of the lifters were being actuated by adjacent lobes. The shoulders of the roller lifters were actually riding up on the adjacent lobes and damaging the lifters. I figured that perhaps the cam or block thrust surface might be out of spec. Checking this out revealed that was not the case since some of the lifters needed to be moved forward and some needed to be moved rearward to get "fixed". In each case Comp gladly replaced the cams with another unit that just barely had enough clearance to make me comfortable. They did not seem to care what the problem really was or that it had really caused me a tremendous waste of time.
Yes it is true that the lifter spacing on the 109 block is erratic and slightly different for some of the lifter pairs. The pair spacing of exhaust/intake lifters on the 109 varies from 1.515 on cylinder 2 to a maximum of 1.620 on cylinder 3. While that is a big difference at least all the blocks i have measured are the same to a few thousands. I cannot understand how a company can make a cam that is this far out of wack and not be concerned. The lobes on these cams vary in width from a low of .535 to a high of .590 while the rollers that contact them are only .375. The sides of the lobes are raw "as cast" meanwhile the billet cams have lobes that are precision ground to a few thousands of .485 and have no apparent problems.
I put layout dye on the lifters and let them contact the lobes on this cam so i could show everyone what to look out for. Building an engine with this problem is a recipe for disaster. Other than waiting for replacements that may or may not be usable the only option i have come up with so far is to put the cams in a lathe fitted with a tool post grinder and precision grind the sides of the lobes down to a reasonable width in the range of some of the better billet cams.
Most problematic are #1 exhaust lifter hitting #2 exhaust lobe, #5 intake lifter hitting #6 intake lobe and #5 exhaust lifter hitting #6 exhaust lobe
I hope this info can be of use to anyone contemplating an engine build.
- Joined
- May 26, 2001
We encountered this issue on the first Comp cast roller installation and did not find the problem until the engine was started and a clicking sound was present.
A lot of time was spent to determine the cause like checking push rods, rockers and finally pulled the intake to see the interference with the adjacent lobe.
Comp sent a replace cam after much discussion and find it disturbing to see this problem years later?
On a performance build we prefer to use a billet cam which is more reliable and durable, but worth the added expense.
A lot of time was spent to determine the cause like checking push rods, rockers and finally pulled the intake to see the interference with the adjacent lobe.
Comp sent a replace cam after much discussion and find it disturbing to see this problem years later?
On a performance build we prefer to use a billet cam which is more reliable and durable, but worth the added expense.
- Joined
- May 28, 2001
Richard, how far back in time does this issue go?
No response is another case of the little guy gets ignored.
I'd bet my bottom dollar, had this happened w/ the SBC, LS applications, it would have been "cured' immediately...
Thanks for your headsup!
the first of these occurred sometime around last april/may all of this has been very recent
There was a thread about this issue a few years ago with pictures showing the lifters hitting the adjacent lobes. I remember the person building the motor caught this issue before slapping on the intake.
After reading said thread one reader decided to inspect his new build before starting and also had the same problem.
It’s amazing that comp hasn’t corrected this problem after all these years. They could care less that the debris can cause thousands of dollars in damage with pistons turbos and such.
D
After reading said thread one reader decided to inspect his new build before starting and also had the same problem.
It’s amazing that comp hasn’t corrected this problem after all these years. They could care less that the debris can cause thousands of dollars in damage with pistons turbos and such.
D
there are currently 3 major players in the "cast " cam manufacture.
Engine Power Components (EPC) of Muskegon, MI., and Waver Bartel Cam Company, of Grand Haven, MI.
and Camshaft Machine Company (CMC) located in Jackson, Michigan.
crane purchased CMC, but later sold it to federal mogul.
all are USA companies, and supply 99.9% of cast OEM cams,
as well as all cores to everyone who grinds their own cam.
so its likely on of those 3 , has an error in their casting design.
Engine Power Components (EPC) of Muskegon, MI., and Waver Bartel Cam Company, of Grand Haven, MI.
and Camshaft Machine Company (CMC) located in Jackson, Michigan.
crane purchased CMC, but later sold it to federal mogul.
all are USA companies, and supply 99.9% of cast OEM cams,
as well as all cores to everyone who grinds their own cam.
so its likely on of those 3 , has an error in their casting design.
- Joined
- May 26, 2001
Last edited:
