Valve Spring Seat Clearance Problem
Thread Starter
Intermediate
Joined: Dec 2005
Posts: 44
Likes: 0
From: Raleigh North Carolina
Valve Spring Seat Clearance Problem
Hi Everyone,
I'm getting close to finishing up my engine rebuild, and I'm having trouble getting my valve springs onto the heads.
Heads are Brodix: IK 180 (aluminum)
Springs are Comp Cams: 977
The valve springs that came with the heads have an Outer Diameter of 1.440"
The valve springs that Comp provided (the ONLY ones they recommend with my camshaft) have an OD of 1.460"
It seems like I have a couple options:
1. Purchase a "Valve spring seat cutter", attach it to my power drill, open up those diameters, then purchase and intall valve spring locators, and use the springs Comp provided.
2. Bring the heads to a machine shop and have them machine the valve spring bores to the proper clearance. (Does anyone know how much clearance I should leave?)
3. Find another camshaft & spring set
4. Have Brodix customize a new set of heads for me (lead time 4 weeks).
Let me know if you guys have any experience with the cutting tool that attaches to the power drill (that idea just scares me). Or any other ideas you might recommend!
Thanks!
I'm getting close to finishing up my engine rebuild, and I'm having trouble getting my valve springs onto the heads.
Heads are Brodix: IK 180 (aluminum)
Springs are Comp Cams: 977
The valve springs that came with the heads have an Outer Diameter of 1.440"
The valve springs that Comp provided (the ONLY ones they recommend with my camshaft) have an OD of 1.460"
It seems like I have a couple options:
1. Purchase a "Valve spring seat cutter", attach it to my power drill, open up those diameters, then purchase and intall valve spring locators, and use the springs Comp provided.
2. Bring the heads to a machine shop and have them machine the valve spring bores to the proper clearance. (Does anyone know how much clearance I should leave?)
3. Find another camshaft & spring set
4. Have Brodix customize a new set of heads for me (lead time 4 weeks).
Let me know if you guys have any experience with the cutting tool that attaches to the power drill (that idea just scares me). Or any other ideas you might recommend!
Thanks!
Thread Starter
Intermediate
Joined: Dec 2005
Posts: 44
Likes: 0
From: Raleigh North Carolina
Comp Cams recommended CC part number for the valve springs: 977.
The camshaft is part number: K12-702-8.
The springs that are in the heads now are the ones that Brodix supplied. I'm not sure who makes them or what part number they are.
There is a visibile difference between the Brodix springs and the Comp Cams ones in terms of overall height, and diameter of the wire itself in the spring.
The car will be used for street only. Compression is going to be about 9.8:1
The camshaft is part number: K12-702-8.
The springs that are in the heads now are the ones that Brodix supplied. I'm not sure who makes them or what part number they are.
There is a visibile difference between the Brodix springs and the Comp Cams ones in terms of overall height, and diameter of the wire itself in the spring.
The car will be used for street only. Compression is going to be about 9.8:1
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I have used the 1.550 comp cams cutter using a milling machine. It could even be done with a drill press with a stop set to ensure consistant spring pocket depth.
Any head shop could do it for you. I have never used any kind of spring cup locator. All of the heads i have bought could probably use up to 1.660 springs. I only use 1.56 or 1.55 springs. So the spring pocket hole doesn't even touch the spring.
Any head shop could do it for you. I have never used any kind of spring cup locator. All of the heads i have bought could probably use up to 1.660 springs. I only use 1.56 or 1.55 springs. So the spring pocket hole doesn't even touch the spring.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I just looked up your springs and cam choice. IMO - I would not run springs with so little seat pressure (133#)on a hot rod 236/236 .550/.550 solid roller cam. You are just asking for valve float if you start exceeding 6000 - 6500 rpm
Springs are only good the day you install them. Every day later they degrade. I can start out with 190 - 200 pound seat on my solid roller setup and at the end of the summer they only read 175#
When i first looked up CC 977 springs i just guessed that you must be installing a solid cam or maybe even an H-Roller.
I would find out if those brodix spring were recommended for a SR cam. And I would also investigate getting 1.55 springs with closed pressures more like 175# minimum.
What size motor is this anyway.
Springs are only good the day you install them. Every day later they degrade. I can start out with 190 - 200 pound seat on my solid roller setup and at the end of the summer they only read 175#
When i first looked up CC 977 springs i just guessed that you must be installing a solid cam or maybe even an H-Roller.
I would find out if those brodix spring were recommended for a SR cam. And I would also investigate getting 1.55 springs with closed pressures more like 175# minimum.
What size motor is this anyway.
Advanced
Joined: Feb 2007
Posts: 90
Likes: 0
The camshaft is part number: K12-702-8.
You have another problem that might come back to get you later. You should not be using a cast cam blank for a mechanical roller. They barely work on hydraulic rollers, really not good choice for mechanicals.
Springs are another seperate area to deal with.
Who is guiding you with the parts you have?
Harry P. Hunter
You have another problem that might come back to get you later. You should not be using a cast cam blank for a mechanical roller. They barely work on hydraulic rollers, really not good choice for mechanicals.
Springs are another seperate area to deal with.
Who is guiding you with the parts you have?
Harry P. Hunter
Thread Starter
Intermediate
Joined: Dec 2005
Posts: 44
Likes: 0
From: Raleigh North Carolina
The motor is a 350.
I am not planning on using the Brodix springs for anything other than paperweights.
The Comp Cams springs (P/N 977) that I have were recommended by them for my Solid Roller Camshaft.
Where can I find out what thier initial seat pressure is?
I am not planning on using the Brodix springs for anything other than paperweights.
The Comp Cams springs (P/N 977) that I have were recommended by them for my Solid Roller Camshaft.
Where can I find out what thier initial seat pressure is?
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I don't know the total flow of your heads or if your going to use a single plane intake. But that cam would not have a problem reving a little 350 to 7500+ rpm. I used something simular in the billet steel 236/242 and it would hit my 7500 rev limiter periodically
http://www.compcams.com/technical/Ca...07/296-306.pdf
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Burning Brakes
Joined: Feb 2005
Posts: 894
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Heads Up Here Guys
The camshaft is part number: K12-702-8.
You have another problem that might come back to get you later. You should not be using a cast cam blank for a mechanical roller. They barely work on hydraulic rollers, really not good choice for mechanicals.
Springs are another seperate area to deal with.
Who is guiding you with the parts you have?
Harry P. Hunter
You have another problem that might come back to get you later. You should not be using a cast cam blank for a mechanical roller. They barely work on hydraulic rollers, really not good choice for mechanicals.
Springs are another seperate area to deal with.
Who is guiding you with the parts you have?
Harry P. Hunter
Harry is 100% correct about using a cast cam blank on a solid roller unit, it is asking for trouble with a failure of both the lobes AND the roller lifters.
You should NEVER use a -8 blank for that platform. It WILL NOT hang out for too long.
ALL roller units built here now get a -9 blank with cast distributor drive gear. You've been warned (twice)!!!!
Thanks, Gary in N.Y.
P.S. You can get the identical cam from Comp but on a steel blank. Distributor gear choice is also important here, as well as the fuel pump pushrod if you're using one.
Thread Starter
Intermediate
Joined: Dec 2005
Posts: 44
Likes: 0
From: Raleigh North Carolina
Thanks for the warning about the cast cam blank. I purchased the Cam, roller lifters, and valve springs from Comp as a kit. So I'm surprised that they would sell that kit if its considered unreliable. I'm going to give them a call and see what they'll charge for swapping the camshaft I have with one with a steel blank.
As for the fuel pump pushrod and the dist. gear, I've purchased some that are specified for use on the roller cam.
Thanks guys!
As for the fuel pump pushrod and the dist. gear, I've purchased some that are specified for use on the roller cam.
Thanks guys!
