few questions after cam install! need some help
#1
few questions after cam install! need some help
Ok guys I have a 97 corvette
Just installed the Brian Tooley Racing stage 2 NA cam
specs are 227/234 .614"/.576" 113+2
My valvetrain is super noisy and and my power flatlines at 5500 RPM when I expected this cam to make power up to 6000
Nothing else was changed.. I still have stock heads, intake and lifters.
Im previously had a texas speed 228R and used 7.400 pushrods with no issues. (.588 lift)
BTR recommended that I went with 7.400 on this cam as well so I did and It sounds like im driving around a herd of sewing machines.. Im aware that any cam will be noisier than stock but Ive had other cammed cars and this is excessive
Ive read about guys going with a 7.425 pushrod just to quiet things up and so im concerned that Since my intake lobe has so much more lift, I feel like thats what causing the noise
Is it a bad idea to run a different length pushrod on the intake valves vs the exhaust?
If I switch to a 7.425, is that a big enough difference that I would blow out my lifters or run into clearance issues?
I currently dont really have a way to measusre to get my dead on pushrod length.
What would you guys do in my situation??
Hopefully some vendors will chime in as well!
Just installed the Brian Tooley Racing stage 2 NA cam
specs are 227/234 .614"/.576" 113+2
My valvetrain is super noisy and and my power flatlines at 5500 RPM when I expected this cam to make power up to 6000
Nothing else was changed.. I still have stock heads, intake and lifters.
Im previously had a texas speed 228R and used 7.400 pushrods with no issues. (.588 lift)
BTR recommended that I went with 7.400 on this cam as well so I did and It sounds like im driving around a herd of sewing machines.. Im aware that any cam will be noisier than stock but Ive had other cammed cars and this is excessive
Ive read about guys going with a 7.425 pushrod just to quiet things up and so im concerned that Since my intake lobe has so much more lift, I feel like thats what causing the noise
Is it a bad idea to run a different length pushrod on the intake valves vs the exhaust?
If I switch to a 7.425, is that a big enough difference that I would blow out my lifters or run into clearance issues?
I currently dont really have a way to measusre to get my dead on pushrod length.
What would you guys do in my situation??
Hopefully some vendors will chime in as well!
#5
TECH Apprentice
#7
TECH Apprentice
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#10
TECH Resident
iTrader: (1)
This surprises me, that the base circle is different. I'v been working on Fords for the last couple of decades. The base circle is always the same for a hydraulic roller, regardless of the cam profile. Of course, .688 lift on a SBF is pretty rare.
So, is this a common practice? Will the base circle vary from cam to cam, depending on profile? When I replace the cam should I measure base circles?
So, is this a common practice? Will the base circle vary from cam to cam, depending on profile? When I replace the cam should I measure base circles?
#11
TECH Apprentice
LS1 cam have a 2.165 main cam bearings. If we make a .320 lobe lift and leave the top of the lobe .005 below the bearing we need to make the base circle 1.515 if we make a .360 lobe lift and have the tip of the lobe .005 below the bearing we need to make the base circle 1.435. On some OHC you can make the base circle the same size even with a higher lift.
This surprises me, that the base circle is different. I'v been working on Fords for the last couple of decades. The base circle is always the same for a hydraulic roller, regardless of the cam profile. Of course, .688 lift on a SBF is pretty rare.
So, is this a common practice? Will the base circle vary from cam to cam, depending on profile? When I replace the cam should I measure base circles?
So, is this a common practice? Will the base circle vary from cam to cam, depending on profile? When I replace the cam should I measure base circles?
#13
TECH Resident
iTrader: (1)
LS1 cam have a 2.165 main cam bearings. If we make a .320 lobe lift and leave the top of the lobe .005 below the bearing we need to make the base circle 1.515 if we make a .360 lobe lift and have the tip of the lobe .005 below the bearing we need to make the base circle 1.435. On some OHC you can make the base circle the same size even with a higher lift.
#15
LS1 cam have a 2.165 main cam bearings. If we make a .320 lobe lift and leave the top of the lobe .005 below the bearing we need to make the base circle 1.515 if we make a .360 lobe lift and have the tip of the lobe .005 below the bearing we need to make the base circle 1.435. On some OHC you can make the base circle the same size even with a higher lift.
1. Select a core with a 1.475 base and cut it down to 1.435 for intake only? (2 different base sizes)
2. Select a core with 1.435 and cut the .340 lobe on the smaller base? (1 base size)
3. Find a core with an intake and exhaust near what you need?
Last edited by Goody_Seven; 03-31-2014 at 08:34 PM.
#16
TECH Apprentice
So, I realize this is a Comp cam and not yours, but in a situation like this, say you have a .360/.340 lobes and need the 1.435 core for your intake lobe. When you select the core do you:
1. Select a core with a 1.475 base and cut it down to 1.435 for intake only? (2 different base sizes)
2. Select a core with 1.435 and cut the .340 lobe on the smaller base? (1 base size)
3. Find a core with an intake and exhaust near what you need?
1. Select a core with a 1.475 base and cut it down to 1.435 for intake only? (2 different base sizes)
2. Select a core with 1.435 and cut the .340 lobe on the smaller base? (1 base size)
3. Find a core with an intake and exhaust near what you need?
#17
12 Second Club
iTrader: (4)
Call up a vendor and get a pushrod lenth tool. I think I got the trickflow one from summit for $12. Vendors have the comp tool for around $20 and go to harbor freight and get a 8" digital calipers for around $30. No more guessing for under $60. I used to guess to and $300 worth of pushrods later I found out all 3 set were to long. Wasted money .
#18
TECH Fanatic
iTrader: (11)
My TSP 228R with .588" lift had a smaller base than stock. Had to run 7.425". You really have to measure, all else is a guess given Kip's is more of a hypothesis than a guess. :-)
The OHC motors do not have this smaller base circle restriction given that the cam does not slide in through the bearing to be installed. If you look at some of the aftermarket LSx blocks you will see that they have larger cam bearings allowing crazy solid roller lifts.
The OHC motors do not have this smaller base circle restriction given that the cam does not slide in through the bearing to be installed. If you look at some of the aftermarket LSx blocks you will see that they have larger cam bearings allowing crazy solid roller lifts.
#19
I ran a 7.400 with my 228 also and it was kinda noisy but not anything like this..
Kip should I leave the 7.400 on the exhaust and run 7.425 on intake?
or 7.425 on both
Kip should I leave the 7.400 on the exhaust and run 7.425 on intake?
or 7.425 on both
#20
TECH Veteran
iTrader: (14)
like everyone else said man just measure. it will take all the guess work out. in reality a 7.425 will probably be good if the heads and deck are uncut but why take the chance. I would order the 7.425's and the checker tool. then you can measure and if it works then great if not then simply return them and get the correct length