What I found on my $400 "fresh machined" #6 heads
#1
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Join Date: Dec 2006
Location: Melville, Saskatchewan
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What I found on my $400 "fresh machined" #6 heads
This guy did seem honest, I measured 2.07"/1.56" valves. I opened them up to find a cutter was used under the intake valve and the bowl was opened and the guides were machined for positive seals. I got my snap gauges and 0 to 1" micrometer, so I will measure guide clearance since I am not filling the cross overs on these heads, will work fine with my Performer intake. Here are some pics.
#2
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Another question, are new guides smooth inside? These have a pattern like a knurling was done, not smooth inside. Either way more work than I thought on these heads.
#3
That looks typical to me. Nothing to be alarmed about.
As I understand knurling, it is an oil control and helps keep the guide lubricated while still maintaining tolerance. Some consider its a short cut but other wise can provide a good service life, and its been done for a long time.
Ask your self, what did you expect for 400 bucks? I'd run em.
As I understand knurling, it is an oil control and helps keep the guide lubricated while still maintaining tolerance. Some consider its a short cut but other wise can provide a good service life, and its been done for a long time.
Ask your self, what did you expect for 400 bucks? I'd run em.
#5
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Join Date: Dec 2006
Location: Melville, Saskatchewan
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That looks typical to me. Nothing to be alarmed about.
As I understand knurling, it is an oil control and helps keep the guide lubricated while still maintaining tolerance. Some consider its a short cut but other wise can provide a good service life, and its been done for a long time.
Ask your self, what did you expect for 400 bucks? I'd run em.
As I understand knurling, it is an oil control and helps keep the guide lubricated while still maintaining tolerance. Some consider its a short cut but other wise can provide a good service life, and its been done for a long time.
Ask your self, what did you expect for 400 bucks? I'd run em.
#10
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I know but I may leave them as is, not a max effort build, I will be happy with 325 hp and 350 tq, stock 76 bottom end with a Cutlassefi custom cam. With a 2300 flash stall, 2004R, and a 3.90 posi to replace the 2.78 open should reach high 13's. The guy thought nothing was done to the bowls and the positive seals were unexpected as well.
#11
#12
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#16
I know but I may leave them as is, not a max effort build, I will be happy with 325 hp and 350 tq, stock 76 bottom end with a Cutlassefi custom cam. With a 2300 flash stall, 2004R, and a 3.90 posi to replace the 2.78 open should reach high 13's. The guy thought nothing was done to the bowls and the positive seals were unexpected as well.
Take the time and blend the seats, the heads are off.
Also, your valve to guide clearances are subject to scrutiny. It takes a talent to distinguish the actual size of the guide with a ball gauge. I personally sucked at it for a lot of years. I was always on the high side of size.
Also, iron replacement guides usually have a knurl in them to begin with. Your heads definitely have iron replacement guides, and the knurl is normal. That can mess with your clearance numbers.
At the end of the day, you should check all clearances on every guide. Why? Because you can. It's good practice.
#17
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Thanks, they do look like replacements and would make sense with $1200 originally spent on them. I measured by the same guide a few times to get what felt right. What is the minimum clearance for iron replacement guides in the center exhaust guides? I will measure some more and may do some careful blending.
#18
Thanks, they do look like replacements and would make sense with $1200 originally spent on them. I measured by the same guide a few times to get what felt right. What is the minimum clearance for iron replacement guides in the center exhaust guides? I will measure some more and may do some careful blending.
#19
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I will measure my #8 heads installed height and them measure another set of guides in the next few days. I may be off, as you said not easy to measure. I need to get the same tension on valve and snap gauge with the mic. I also need to get the snap gauge adjusted right in the guide. I have a set of Comp roller tips but they are loud in my aluminum valve covers plus I need conversion studs or tap to 3/8" and steal off my other heads.
Last edited by olds 307 and 403; December 23rd, 2016 at 10:36 AM.
#20
What do you mean by " snap Gauges" ? Are they like telescopic gauges? if so they are difficult to use until you get good with them. Maybe the shop that did the heads for you have a set of Pin gauges for small diameter holes you are trying to get a measurement from.
I've been in the Tool & Die/ machining trade for over 30 years and still have a hard time with telescopic gauges haha, and they aren't a cheap set they are Starrett.
I've been in the Tool & Die/ machining trade for over 30 years and still have a hard time with telescopic gauges haha, and they aren't a cheap set they are Starrett.
#21
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What do you mean by " snap Gauges" ? Are they like telescopic gauges? if so they are difficult to use until you get good with them. Maybe the shop that did the heads for you have a set of Pin gauges for small diameter holes you are trying to get a measurement from.
I've been in the Tool & Die/ machining trade for over 30 years and still have a hard time with telescopic gauges haha, and they aren't a cheap set they are Starrett.
I've been in the Tool & Die/ machining trade for over 30 years and still have a hard time with telescopic gauges haha, and they aren't a cheap set they are Starrett.
Last edited by olds 307 and 403; December 25th, 2016 at 07:26 AM.
#22
Do you have a depth mic? That would give you bang on measurements in the spring pockets. You could put a steel rule over the valve cover rail, use a caliper as a depth mic and measure them just subtract the steel rule from the height.
I'm learning a little bit from measuring the heads I have to duplicate, I met a guy that owns Red Line racing up here who is helping me out with these heads. I hope to get more time in the new year to continue with my experimental heads.
Sounds like your doing an awesome job with your engine, I'm learning from you all here.
Cheers
Eric
I'm learning a little bit from measuring the heads I have to duplicate, I met a guy that owns Red Line racing up here who is helping me out with these heads. I hope to get more time in the new year to continue with my experimental heads.
Sounds like your doing an awesome job with your engine, I'm learning from you all here.
Cheers
Eric
#23
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No depth mic, as long as it is close enough to not bend push rods is my goal. I will be using composite head gaskets .011" thicker than the factory shim head gaskets.
#25
Out of Line, Everytime😉
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Location: Melville, Saskatchewan
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With a 2200 stall, 200-4R, 3.73 rear, with stock small valve #7 heads I went 13.02 @ 103mph with a 73 stock 350 bottom end in a car (78 Cutlass with power windows and seats) that weighed 3450lbs with me in it. That was with a Lunati 221/230 cam. Perfect street car with all the manners you would expect. 9:1 compression.
Take the time and blend the seats, the heads are off.
Also, your valve to guide clearances are subject to scrutiny. It takes a talent to distinguish the actual size of the guide with a ball gauge. I personally sucked at it for a lot of years. I was always on the high side of size.
Also, iron replacement guides usually have a knurl in them to begin with. Your heads definitely have iron replacement guides, and the knurl is normal. That can mess with your clearance numbers.
At the end of the day, you should check all clearances on every guide. Why? Because you can. It's good practice.
Take the time and blend the seats, the heads are off.
Also, your valve to guide clearances are subject to scrutiny. It takes a talent to distinguish the actual size of the guide with a ball gauge. I personally sucked at it for a lot of years. I was always on the high side of size.
Also, iron replacement guides usually have a knurl in them to begin with. Your heads definitely have iron replacement guides, and the knurl is normal. That can mess with your clearance numbers.
At the end of the day, you should check all clearances on every guide. Why? Because you can. It's good practice.
#26
Out of Line, Everytime😉
Thread Starter
Join Date: Dec 2006
Location: Melville, Saskatchewan
Posts: 9,145
The installed height on the #8 head and #6 heads looks like just under 1.5" on both from the valve tops to the valve cover gasket surface. I should probably have the Mondollar tool to double check.
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