Here We Go: My 383 Stroker Winter Project

[Tail_Gunner]

Re: Here We Go: My 383 Stroker Winter Project

I hope i dont sound demanding..i do not mean to. Here is a link for a tool http://www.summitracing.com/parts/CCA-4710/ Push rod holes arent that bad to tap....however tapping the apr bolts does take precision. As to polishing (Not Porting) the vortec heads its not hard nor a big deal. They are set up right by desgin right out of the box all one need to do is smooth out casting and polish the iron takes maybe 8 hours ahh the simple guide.... http://65corvette.nonethewiser.net/technical/diyport.pdf..The trick here is to get a fine 80 grit finish on the intake runners removing all the casting lines or imperfections...Now one the exhaust side..like glass if you can or willing or obsesvie

Building a motor can be fascinating for my self in the fact that its all the little things that count up to a big event..Heres is a very good thought.. http://webcache.googleusercontent.c...ec+heads+power+limit&cd=1&hl=en&ct=clnk&gl=us

WHAT ARE THE APPROXIMATE HP/TQ LIMITS for VORTEC HEADS? well lets look at it!
approximate potential hp is found by this formula (.257 x max air flow x cylinders=potential hp) so .257 x 239 x 8=491hp potentially now figure about 90% efficiency is about max for most street combos and we get a reasonable figure around 442hp to shoot at, lets look at some combos,

STOCK vortec heads have a relatively small port size and 1.94" int/1.5" exhaust valves

valve lift figures over about .520 in mildly modifyed /clearanced heads or .450 in stock heads do little to increase flow, they were designed for massive torque in the 1000rpm-4500rpm range, minor mods easily increase flow to about the 4700rpm range, while EXCELLENT FLOWING HEADS FOR THIER PORT SIZE they are NOT RACING HEADS heres some combos useing vortec heads
from this sitehttp://www.ryanscarpage.50megs.com/combos1.html

keep in mind that torque peaks at almost exactlt the rpm where air flow efficiency peaks


You have already done some of the mods...The 1.6 lift by product is the somewhat the same as increasing vavle size..the lift still starts @ 50 but the valve stays open longer and againg closes @ 50 getting you closer to effecincy i believe its a 7% gain....smoothing our the heads my get 5%. If all that pans out and it should thats a net of about 45 hp...Then there is parasitic loss...It never ends

:facepalm:


By the way i believe you machinst should have tapped the studs and drillled the guides...He knew you were going to a high lift cam on vortecs..Its all old stuff

 

[greg82255]

Re: Here We Go: My 383 Stroker Winter Project

You can make easy gains, maybe 10 to 20 hp in upper rpm's by doing simple things like ...
blending the bowls
contour and smoothing the guide boss
unshrouding the valves
gasket match
smoothing the short side radius

You could also kill air velocity and loose 20 or more hp down low if you don't know what you are doing.

Joe could you explain what you mean by each of those? I understand gasket matching, and I think I get smoothing the short side radius (intake and exhaust ports?), but I'm not sure what the others are. When you say smoothing the guide boss do you mean the rocker stud bosses we have been talking about, or something else?

You have already done some of the mods...The 1.6 lift by product is the somewhat the same as increasing vavle size..the lift still starts @ 50 but the valve stays open longer and againg closes @ 50 getting you closer to effecincy i believe its a 7% gain....smoothing our the heads my get 5%. If all that pans out and it should thats a net of about 45 hp...Then there is parasitic loss...It never ends

:facepalm:


By the way i believe you machinst should have tapped the studs and drillled the guides...He knew you were going to a high lift cam on vortecs..Its all old stuff

I'm not really interested in spending any more $ for someone else to port the heads. I'm going to take a good look at that DIY head porting guide now (thank you Tail Gunner) and see if I think I can do it myself. If I feel comfortable enough with it then I'll give it a shot, otherwise I'll probably leave them be for now. I'm not sure how far above 400 hp I want to be anyways - I'm already starting a fund for the new alpha drive I'll eventually need.

I think the machinist probably should have done the extra head work too (threaded studs and push rod holes)... It seems like he has either ignored some of the smaller details of this build, or doesn't think they are necessary (upgraded distributor gear, using a retro cam, brass tip fuel pump rod, now the heads, etc). So I think at this point, I have all my parts back and I don't want to bring them back and tell him he didn't do something he should have and get into an argument over it. He's been in the industry for as long as I've been alive so he's not going to listen to me tell him what needs to be done. I'll just buy the tools I need and do what I need to do - tapping holes in cast iron shouldn't be too hard, especially with that comp cams guide tool.

 

[John_S]

Re: Here We Go: My 383 Stroker Winter Project

Greg,

I have not drilled and taped heads for screw in studs, so can't say how easy or hard it may be. My recommendation is to practice on your old heads, or get some junkyard trashed ones.

 

[greg82255]

Re: Here We Go: My 383 Stroker Winter Project

Greg,

I have not drilled and taped heads for screw in studs, so can't say how easy or hard it may be. My recommendation is to practice on your old heads, or get some junkyard trashed ones.

I definitely think that's a good idea. I have an old 2bbl intake that I've tried to sell for 2 years without any luck, so I'll probably just drill and tap its carb studs as practice. The manifold is cast iron so it should be the same as tapping the heads.

 

[joewithaboat]

Re: Here We Go: My 383 Stroker Winter Project

This is a decent video showing tapping by hand.

http://www.youtube.com/watch?v=3isVcqtCn6E

-make sure you use lots of tapping fluid
-back off 1/2 turn for every 1 turn forward while cutting threads
-make sure to not go too far with tap. Might need a measuring device, cheap dial calipers
-seal the threads, I like the white ptfe based stuff. Every body sells it ARP, Loctite corp, permatex etc.
-torque to stud manufactures spec

I will dig thru the storage unit for my books on porting info. All of the stuff i have was pre vortec. Once again I would look for a printed reference with pictures of before and after for porting your specific head. Ive looked around on the net for good stuff and have not found any. most was an absolute joke and they do more damage than good.

 

[joewithaboat]

Re: Here We Go: My 383 Stroker Winter Project

Here is an actual back to back test of vortec style heads, OE and after market on the same short block with the same induction. Note that mildly ported OE heads gained 3 ft lbs and lost 1 hp and moved the powerband up 100 rpm. Not worth chancing getting it wrong in my opinion.

With gasket matching most folks make the mistake of simply putting the gasket up the the head and intake and making it the same size without ever checking how they actually mate up assembled on the block. Machining the deck or surfacing the head will change the relationship of the two mating surfaces. Sometimes the smarter thing is to leave the intake a little smaller than the head port entry to alleviate the possibility of a port mismatch and interrupting airflow.

 

[greg82255]

Re: Here We Go: My 383 Stroker Winter Project

Thanks for the video - he seems to tap the hole fairly easily, and it's the exact same casting as mine (906 heads). It looks like it won't be too hard but will take some time.

I read the article that Tail_Gunner posted on head porting and I really don't think that I am up to the task. I am way too afraid of screwing something up. Plus I tend to get impatient sometimes, so adding a tedious job that will take 10-12 hours and lots of precision may not be the best thing for me. Maybe I'll upgrade to AFR heads in a year or 2. I'll definitely do the intake gasket matching, and I'm pretty sure the exhaust ports are bigger than the heads anyways. I have the stock mercruiser exhaust manifolds but I can't decide if I want to sell those and upgrade to a more powerful exhaust system like CMI or IMCO powerflow or something. They all look great but I can't get myself to spend $2000 on a new exhaust.

 

[Scott Danforth]

Re: Here We Go: My 383 Stroker Winter Project

keep checking craigslist for a set of IMCO powerflows. every once in a while I look and can find them in the $1000 range new because someone bought them and never got around to installing them. nothing on there now, however there was a pair in Tulsa for $900 a few weeks ago.

I wouldnt worry about porting and polishing your heads. the 383 will put such a smile on your face when you fire it up, I doubt you would even miss the few hp's that you may or may not have gained.

 

[greg82255]

Re: Here We Go: My 383 Stroker Winter Project

I'll definitely keep checking ebay and craigslist every day and hope I stumble across the right deal.

I got to working on the motor today - the studs and tapping tool came in. Pulling these studs is not an easy task. I ended up stripping the threads on one of them after it moved up about 1/4 inch, and now I'm a little unsure how its going to come out. I haven't done any more because I need to figure out a better way to get them out. I was only using grade 5 bolts - so maybe i need grade 8. Any suggestions?

Also, I took 2 of the springs off the head today to put in test springs for when I measure the pushrods, and I noticed that there were shims under the springs. Of the 2 springs I pulled, there were 2 shims under one of them and one shim under the other. Is it normal to have a different number of shims (or any at all for that matter) with new springs? I figured the new springs would not need them..

 

[RogersJetboat454]

Re: Here We Go: My 383 Stroker Winter Project

Also, I took 2 of the springs off the head today to put in test springs for when I measure the pushrods, and I noticed that there were shims under the springs. Of the 2 springs I pulled, there were 2 shims under one of them and one shim under the other. Is it normal to have a different number of shims (or any at all for that matter) with new springs? I figured the new springs would not need them..

They will be fine. Just don't mix them up. There is differences in the installed height of the springs between how far the valve seats in the head, the machining for the valve spring pocket, the spring/valve retainer fit, and the springs them selves. Kinda like setting up a rear diff. Though the parts are new, there will be unavoidable variations in all the factors listed above that can be adjusted by installing the correct shims.

Read through this for your edification;
http://www.lunatipower.com/Tech/Valvetrain/ValveSpringTech.aspx

 

[joewithaboat]

Re: Here We Go: My 383 Stroker Winter Project

I'll definitely keep checking ebay and craigslist every day and hope I stumble across the right deal.

I got to working on the motor today - the studs and tapping tool came in. Pulling these studs is not an easy task. I ended up stripping the threads on one of them after it moved up about 1/4 inch, and now I'm a little unsure how its going to come out. I haven't done any more because I need to figure out a better way to get them out. I was only using grade 5 bolts - so maybe i need grade 8. Any suggestions?


Also, I took 2 of the springs off the head today to put in test springs for when I measure the pushrods, and I noticed that there were shims under the springs. Of the 2 springs I pulled, there were 2 shims under one of them and one shim under the other. Is it normal to have a different number of shims (or any at all for that matter) with new springs? I figured the new springs would not need them..

Grade eight should help, a little oil as well. Its not the end of the world, you may have to cut it off and drill it out. It happens even with the industrial type puller we used in the machine shop, which you can pull them all in like 5 min. If you still have some threads left a little heat on the head will help the cast iron expand a little and let loose. By a little i mean your not trying to turn it red or anything. You can use a propane torch or even a good heat gun. How many have you gotten out. Let us know if you need to drill it.


Shims are used to obtain proper installed height of the spring to get the proper seat pressure and compressed or open pressure.
You need to keep track of all of the springs, shims,valves etc. Number the valves with a sharpie, use a scrap piece of plywood and some nails to organize the shims and springs. Label them as well on the plywood.

Most of the time properly rebuilt heads should have the same thickness shims under all the exhaust valve springs then maybe a different thickness under all of the intake valve springs. Give us some good pictures.

 

[greg82255]

Re: Here We Go: My 383 Stroker Winter Project

I only removed 2 springs to install test springs. I didn't think I needed to remove the others if I am just removing studs and tapping holes. Would it be better to remove all the springs? It wasn't hard to do it (thanks to craftsman's $19.99 valve spring compressor), so if it's necessary I'll take the rest out.

I was able to get 3 of the rocker studs out very easily. The other 5 on this head are anywhere from 1/3 to 90% out, and all have a few threads left intact. Haven't touched the 2nd head yet. I was using grade 8 bolts this time, and used a new bolt for each stud I pulled along with some oil, and that seemed to help a lot. In case I can't get these out, any idea what a machine shop would cost to pull out the 8 studs in the other head along with the 5 I screwed up? Joe, I know you mentioned I can drill them, and I may still do that, but if it's cheap enough I may just have someone else do it.

Completely forgot to take pictures today. I'll get some up as soon as I take them tomorrow. I'm actually taking a firearms safety course tomorrow morning so I won't get to the motor until the afternoon.

 

[joewithaboat]

Re: Here We Go: My 383 Stroker Winter Project

I only removed 2 springs to install test springs. I didn't think I needed to remove the others if I am just removing studs and tapping holes. Would it be better to remove all the springs? It wasn't hard to do it (thanks to craftsman's $19.99 valve spring compressor), so if it's necessary I'll take the rest out.

I was able to get 3 of the rocker studs out very easily. The other 5 on this head are anywhere from 1/3 to 90% out, and all have a few threads left intact. Haven't touched the 2nd head yet. I was using grade 8 bolts this time, and used a new bolt for each stud I pulled along with some oil, and that seemed to help a lot. In case I can't get these out, any idea what a machine shop would cost to pull out the 8 studs in the other head along with the 5 I screwed up? Joe, I know you mentioned I can drill them, and I may still do that, but if it's cheap enough I may just have someone else do it.

Completely forgot to take pictures today. I'll get some up as soon as I take them tomorrow. I'm actually taking a firearms safety course tomorrow morning so I won't get to the motor until the afternoon.

If you completely striped the threads, the industrial puller that is made to do that would not help. So the machine shop would just be cutting them off flush and drilling them. You start with an 1/8 inch pilot, then go to 1/4 and use an easy out. The square easy outs seem to work best for that.
Try a little heat on the other head, you shouldn't be stripping them that easy.

You would be best served taking the heads apart after tapping the stud holes to make sure you get all of the shavings out.

 

[joewithaboat]

Re: Here We Go: My 383 Stroker Winter Project

As far as what it will cost if a shop does it ? It is one of the most common things done to a small block chevy, It can be done in 1 hour by anyone who does it regularly. I'm sure rates vary drastically from shop to shop. I would find out where all the dirt track racers go in your area. That is where the best rates will be. They should also be very familiar with those heads.
Good luck.

 

[greg82255]

Re: Here We Go: My 383 Stroker Winter Project

If you completely striped the threads, the industrial puller that is made to do that would not help. So the machine shop would just be cutting them off flush and drilling them. You start with an 1/8 inch pilot, then go to 1/4 and use an easy out. The square easy outs seem to work best for that.
Try a little heat on the other head, you shouldn't be stripping them that easy.

You would be best served taking the heads apart after tapping the stud holes to make sure you get all of the shavings out.

I'll try some heat and grade 8 nuts on the other head and see where I get. It definitely looks like Ill have to drill some of the studs on the first one. Just to be sure - To do that, I cut the stud flush with the boss, drill a 1/8 pilot hole, then widen it with a 1/4" bit and use an easy out? The easy outs I have are for removing bolts with stripped threads - will it work the same way for the pressed in studs?

 

[Alwhite00]

Re: Here We Go: My 383 Stroker Winter Project

Good looking project, I'm glad you are using all the advice that is given to you - People in numbers is great. I didn't read EVERY post but I have not seen any talk about the distributer gear, That will need to be bronze on that roller cam.

Keep the pics comming.

LK

 

[joewithaboat]

Re: Here We Go: My 383 Stroker Winter Project

I'll try some heat and grade 8 nuts on the other head and see where I get. It definitely looks like Ill have to drill some of the studs on the first one. Just to be sure - To do that, I cut the stud flush with the boss, drill a 1/8 pilot hole, then widen it with a 1/4" bit and use an easy out? The easy outs I have are for removing bolts with stripped threads - will it work the same way for the pressed in studs?

Yes, cut it flush or as near flush as possible without messing up the end of the cast iron stud boss. One of those zip wheel cutting discs would work. Depending on what you are cutting it with you could hit it with a file to give you a nice flat spot to hit it once or twice with a center punch. Then drill a 1/8 hole, then 1/4, then use those easy outs. Yes the ones for bolts will work. I have had stubborn ones that were very rusty in the water jacket, which might be your problem, that i had to continue to drill even closer to the final size and just use a pick and pry the remains out after drilling almost all of it out. You just don't want to damage the hole so much that it wont take the new threads.

http://www.sears.com/shc/s/p_10153_12605_SPM210108952P?prdNo=20&blockNo=45&blockType=G45

http://www.sears.com/shc/s/p_10153_12605_SP101A9692S5876473706P?prdNo=18

http://www.sears.com/shc/s/p_10153_12605_SPM5824556303P?prdNo=22&blockNo=22&blockType=G22

These will work together and not break the bank, name brand will be better for the air powered grinder. Sears, Home Depot, Harbor Freight all have that stuff. You can also use a sawzall... might want to slide a large washer down over the stud to protect the cast iron if doing this way. Just some ideas.

Also If they are almost out and you haven't cut them yet.... Do you have a slide hammer? You could rig up a set up to attach the slide hammer to the studs.

Good luck, have fun don't rush things you haven't done before.

 

[greg82255]

Re: Here We Go: My 383 Stroker Winter Project

I think I screwed up pretty bad today. Hopefully this head is still usable... I got 6 of the studs out, 4 using some threads that were still intact, and 2 by drilling and extracting. The last 2, however, are being incredibly stubborn. I managed to break a 1/4" drill bit in the one on the left, and after I got the bit out I started to hammer in the extractor (obviously way too hard). The stud started to move down farther into the boss. Now the extractor tool is stuck in the stud and they are both about 1/2" down into the boss. The other stud in the picture has a different extractor tool stuck in it (I know it's hard to see, but trust me it's there). I was getting angry so I decided to put everything down and come inside. Any idea what to do now? Is this head still usable?

 

[joewithaboat]

Re: Here We Go: My 383 Stroker Winter Project

Yea, take it easy! You are hitting things too hard! Be careful you will break through to the water jacket below.
The one on the end is a drill bit?
The one that is flush has an extractor broke off in it?

PM SENT

 

[Alwhite00]

Re: Here We Go: My 383 Stroker Winter Project

An screw extractor is for just that, Extracting screws (bolts) What were you trying to accomplish with the extractor? I never use them anymore because every time I tried to use one it ended up breaking off and now you have hardened steel to deal with, They should outlaw the damn things.

Now it's time to pony up and take them to your friendly machine shop and see if they can help you. When they get done laughing at you for trying to do it yourself hopefully they say no bid deal.

Good luck.

LK