SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: coors909 on October 21, 2015, 05:24:10 PM
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I'm going to be pulling my engine and was wondering my bottom end is still in good condition and I have good compression. I need to get a spark plug hole fixed and want to redo my heads. Would it be a bad idea to do head studs and valves and roller rockers and a new cam. I'm already going to buy a bigger carb.
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Sounds like the perfect time and a great idea to me... O0
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Sounds like the perfect time and a great idea to me... O0
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Cool thank you. It helps never done this before.
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A good 5-angle or even a 3-angle valve job would wake those heads up. Can't stress enough the importance of a good valve job.
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A good 5-angle or even a 3-angle valve job would wake those heads up. Can't stress enough the importance of a good valve job.
Which one is better? I'm not sure what it is
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A 5-angle has two additional angles in addition to the common angle of a 3-angle. One 15-degree angle into the combustion chamber and a 75-degree angle into the port. The common three angles are 45-degrees for the seat, this is the surface that the valve head contacts. A 30-degree angle from the seat towards the combustion chamber and a 60-degree angle from the seat towards the port. All angles are measured perpendicular to the valve stem.
With a 2.19 valve, flow at lifts less than .547, the valve seat is the greatest restriction. Anything that can be done to improve this low-lift flow will increase performance. At lifts above this point, the port shape and cross-section area influence flow more than the valve seat.
To take full advantage of this, the valves also need to have a 30-degree back cut and the combustion chamber edge of the valve should be "clipped".
I would contact Bostick, he will do you right.
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A 5-angle has two additional angles in addition to the common angle of a 3-angle. One 15-degree angle into the combustion chamber and a 30-degree angle into the port. The common three angles are 45-degrees for the seat, this is the surface that the valve head contacts. A 30-degree angle from the seat towards the combustion chamber and a 60-degree angle from the seat towards the port. All angles are measured perpendicular to the valve stem.
With a 2.19 valve, flow at lifts less than .547, the valve seat is the greatest restriction. Anything that can be done to improve this low-lift flow will increase performance. At lifts above this point, the port shape and cross-section area influence flow more than the valve seat.
To take full advantage of this, the valves also need to have a 30-degree back cut and the combustion chamber edge of the valve should be "clipped".
I would contact Bostick, he will do you right.
Ok that sounds cool I really want to see what it looks like now when it's done. Where is bostick located? I have a guy that is good but the more the better.
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Ok that sounds cool I really want to see what it looks like now when it's done. Where is bostick located? I have a guy that is good but the more the better.
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. Bostick is in Sante
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I wanted to make a correction. It is 75-degrees from the 60-degree cut into the port from the valve seat.
Check out http://garage.grumpysperformance.com/index.php?threads/multi-angle-valve-job-related.3143/
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I wanted to make a correction. It is 75-degrees from the 60-degree cut into the port from the valve seat.
Check out http://garage.grumpysperformance.com/index.php?threads/multi-angle-valve-job-related.3143/
Thank you. It makes a bit more sense now
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What are some good valve springs to use? Also rocker arms or anything for the heads. I need to figure out of if a 1000 cfm carb is a good idea Holley carb.
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I'm going to be pulling my engine and was wondering my bottom end is still in good condition and I have good compression. I need to get a spark plug hole fixed and want to redo my heads. Would it be a bad idea to do head studs and valves and roller rockers and a new cam. I'm already going to buy a bigger carb.
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It's important that the springs match the camshaft requirements and that they are properly set up and clearanced to eliminate the potential for guide contact and coil bind.
If you are already having the heads worked, it is a perfect time to have them dialed in for the cam that you choose.
Sometimes the guide tips need to be cut down, there are also times that the spring pockets need to be opened up and machined for proper spring fitment.
Seat pressure can also be adjusted.
A good shop should be able to calculate all of this information out for you.
You will also want to have the guides fit the valve a little on the loose side. Most machine shops tend to run the guide to stem clearances too tight, this causes the hot valve to get grabbed by the cold guide and they stick, the piston comes up and whacks the snot out of the valve.
If you are using bronze guides (most often coupled with stainless valves) they need to be opened up even further.
But yes, now is the time.
GT
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What exactly is your application? Race, cruiser, or hot rod?
What heads, what compression, how big of a cam? What fuel do you want to run? Forced induction, nitrous, or naturally aspirated?
What are your realistic performance goals and budget?
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I'm leaving the bottom end alone this winter just going to do the heads and a new cam and some new headers through the transom ones. I'm rebuilding the pump also. Not sure on budget kind of just spending what ever I have to spend month by month.
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What heads? Any idea of compression?
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What heads? Any idea of compression?
Not sure about what heads it has. Compression ratio not sure. I really just want to put a good cam in it something that makes it sound good and give it more power
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After reading through this thread, all I can say is, in my opinion, you’re not going about this correctly with the engine. First, you have to have a plan as to what do you want out of the engine when it’s done. Right now there are too many unanswered questions, get with someone who really knows what they are doing, stick with their professional advice and have a decent budget, do it once and do it right. I would not advise leaving the bottom end as is and just throwing a cam and some head work at it. At minimum, the entire engine should be disassembled to inspect everything and see what quality and condition are the parts you have to work with then make the correct decisions and go from there…..Good luck.
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After reading through this thread, all I can say is, in my opinion, you’re not going about this correctly with the engine. First, you have to have a plan as to what do you want out of the engine when it’s done. Right now there are too many unanswered questions, get with someone who really knows what they are doing, stick with their professional advice and have a decent budget, do it once and do it right. I would not advise leaving the bottom end as is and just throwing a cam and some head work at it. At minimum, the entire engine should be disassembled to inspect everything and see what quality and condition are the parts you have to work with then make the correct decisions and go from there…..Good luck.
Sounds like a good idea. That was the original plan. I might just do headers and 10 quart oil pan. Also the pump.
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