My home inspection of Speedmaster heads

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If anyone is interested, there is a decent article on porting the chamber in the March 2020 Car Craft magazine I just received. They are working on an aluminum LS head but same theory applies to Mopar heads. They go through un-shrouding the intake and exhaust valves on the chamber side and give the before and after flow numbers for just this mod. Went through it briefly but it looks like they get 10-17cfm on both the intake and exhaust between .200-.400" lift. The exhaust gives a little improvement above .400 but intake looks to be done. I think PBR is getting ready or has already done this to his heads. Article has good step by step instructions and pictures that just about anyone should be able to follow. Should be on the news stands soon I would think.
 
If you pulled two heads out of the boxes and one had the cleaned up plug hole the other not you’d wonder why the other wasn’t and would want it done. To say meh..... or I want the unfinished....that’s a waste time...of no importance.... is pure poppy ****! There’s one you don’t hear often!:rofl:
 
PRH said:
These RPM heads, and the copies have been around for quite a while now.
Tons of them have been on the dyno.
I don’t ever recall hearing of anyone having to run the timing at 40* to get the most power when using these heads.

I have to chuckle.......a few exposed threads around the plug has people in a tizzy.
But that big fat low flow valve job is a non-issue.
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I've seen it. Many times. Had a customer with a 572 at MATS and he called and said I keep adding timing and I keep going faster.

I said keep an eye on the plugs and as long as they are happy, you're ok.

After he went a few rounds and red lit, he called and said he was at 42 total. I'm thinking damn, is his timing light junk or something.

So I had him snap me a picture of the plug. He needed a 3/4 reach plug and had a 3/8 reach plug in there.

It ran, just took much more timing.

When he put the correct plugs in there, it went back to 34-36 total.

I've seen that many, many times.
 
gzig5 said:
If anyone is interested, there is a decent article on porting the chamber in the March 2020 Car Craft magazine I just received. They are working on an aluminum LS head but same theory applies to Mopar heads. They go through un-shrouding the intake and exhaust valves on the chamber side and give the before and after flow numbers for just this mod. Went through it briefly but it looks like they get 10-17cfm on both the intake and exhaust between .200-.400" lift. The exhaust gives a little improvement above .400 but intake looks to be done. I think PBR is getting ready or has already done this to his heads. Article has good step by step instructions and pictures that just about anyone should be able to follow. Should be on the news stands soon I would think.
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You won't be getting that magazine much longer. You'll be getting Hot Rod instead.
 
So, if you wanted to have a better valve job done on these heads, would the machine shop have to put in all new valve seats, or could you cut a 3 or 5 angle valve job using the existing seats and then also re-use the existing valves?
 
rednesss said:
So, if you wanted to have a better valve job done on these heads, would the machine shop have to put in all new valve seats, or could you cut a 3 or 5 angle valve job using the existing seats and then also re-use the existing valves?
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They should be able to tune up what is there. The 45° seat could be narrowed a bit and a couple angles below and above it to improve things. Then blend into the bowl to smooth things out.

seats2.jpg
 
rednesss said:
So, if you wanted to have a better valve job done on these heads, would the machine shop have to put in all new valve seats, or could you cut a 3 or 5 angle valve job using the existing seats and then also re-use the existing valves?
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A shop with a Serdi (or other brand of seat cutter) could do the same with radiuses. Those machines cut the seats using carbide inserts instead of grindstones.

serdi2.jpg
 
12many said:
In my defense all I posted was some pics of how the holes are finished on both these heads, and stated that to me it is an attention to detail thing. I wonder why TF does what they do? On first glance it all looks pretty, and for what you pay, they look pretty, with attention to detail that caters to anal guys like me:lol:
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Ok so please clarify this pic is how they came out of the box or after you modified then.
bdc5e005-d79c-4174-b696-c4371fee707d-jpeg.jpg
 
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12many said:
In my defense all I posted was some pics of how the holes are finished on both these heads, and stated that to me it is an attention to detail thing. I wonder why TF does what they do? On first glance it all looks pretty, and for what you pay, they look pretty, with attention to detail that caters to anal guys like me:lol:
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Me too!
 
Ok thanks
I need to edit my post previously were i implied that pic i posted was TF.:BangHead:

Ok post 560 in now edit with proper info.:D
 
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I’ve heard of flame propagation, anyone care to expound on that regarding the two examples of plug situation being discussed? Above my pay grade but Im familiar with the term via the internet!
 
I'm not the one to explain this
But i will try.
When the spark plug fires it takes a moment before the flame is big enough to expand and push the piston down.
we advance the timing until we get the best part of the flame/heat/expansion just after tdc.

YR is implying that the short spark plug caused the fuel expansion to slow causing the extra timing, required, for for optimal burn at the right time.
Please correct me if i didn't get that right............
 
Cudafever said:
I'm not the one to explain this
But i will try.
When the spark plug fires it takes a moment before the flame is big enough to expand and push the piston down.
we advance the timing until we get the best part of the flame/heat/expansion just after tdc.

YR is implying that the short spark plug caused the fuel expansion to slow causing the extra timing, required, for for optimal burn at the right time.
Please correct me if i didn't get that right............
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That's essentially it. The further you move the plug away from the center of the chamber, the more timing required. Look at a hemi. Has virtually zero quench yet runs on 30-32 degrees total. That's spark plug location.

When the plug is up the hole like that, you are essentially retarding the timing. The tests validating this are on the web, published by guys like Dr. Jacobs, who developed the Jacobs ignition systems and many others.

You could also call Champion, NGK, Autolite and ask them. Just going from a standard tip plug to an extended tip (if you can fit the extended tip in there) can be a 1-2 degree reduction in total timing.

Running the plug that far up the hole could easily be 4-6 more total ignition, unless some other factor is involved, like so many guys who love to run a plug that is 2 ranges too hot.
 
yellow rose said:
That's essentially it. The further you move the plug away from the center of the chamber, the more timing required. Look at a hemi. Has virtually zero quench yet runs on 30-32 degrees total. That's spark plug location.

When the plug is up the hole like that, you are essentially retarding the timing. The tests validating this are on the web, published by guys like Dr. Jacobs, who developed the Jacobs ignition systems and many others.

You could also call Champion, NGK, Autolite and ask them. Just going from a standard tip plug to an extended tip (if you can fit the extended tip in there) can be a 1-2 degree reduction in total timing.

Running the plug that far up the hole could easily be 4-6 more total ignition, unless some other factor is involved, like so many guys who love to run a plug that is 2 ranges too hot.
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So using a plug, if it existed, and of correct heat range that was longer to orient ideally would be the best option. Next would be to machine the bore so the standard length plug oriented ideally. Short of that maybe do some mild unshrouding and radiusing like being discussed is my take
 
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12many said:
So using a plug, if it existed, and of correct heat range that was longer to orient ideally would be the best option. Next would be to machine the bore so the standard length plug oriented ideally. Short of that maybe do some mild unshrouding and radiusing like being discussed is my take
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You can get longer plugs, but not in 14 X 1.25 thread that I know of. There may be some weird plug out there. Guess I could look and see.

With everything getting smaller, you are seeing 12 and even 10 mm stuff in automotive applications. Used to only see that stuff in motorcycle stuff and the like.

I'm not sure why they can't get the plug depth correct. It ain't that hard. Obviously, you'd want to lower the plug on the head of you can, but like I said, that may open up some other issues.

The best option is what everyone is doing...unshroud the plug and forget about the little bit of compression loss.
 
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