improving flow for the 3FE’s top end (1 Viewer)

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I'm surprised at the need for such a low DCR. I was under the impression that most engines make the best power between 7.5-8.5 DCR.
 
I wondered if there was an grind intermediate between that and the stockish 250-S that Yspen has been wondering about, but it sounds like their other offerings are hotter than the 262*.

I already asked . I think that is why they advised the 250s grind to me , as I said my priority is torque .
This grind seems to fall in the intermediate category :
Isky Z99+E4 grind
258
INT 21-57
ex 57-21
lift 425 ( same lift as MAF RV )
40* overlap ( same overlap as MAF RV)

I feel bias towards Delta as they were the only company that answered my mails . I contacted about 5 cam grinders.
The 250s grind still has good lift @0.050 ( only two degrees less than the 262 grind) but the low overlap will make all the porting and polishing you did ineffective.
You will need more overlap than stock otherwise you wasted your time by improving airflow .
 
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The 250s grind still has good lift @0.050 ( only two degrees less than the 262 grind) but the low overlap will make all the porting and polishing you did ineffective.
You will need more overlap than stock otherwise you wasted your time by improving airflow .

Yup, high overlap shouldn't be an issue with the work I've done. I was wonder about something intermediate (like that Isky grind) with a mind to a touch less stress on the valvetrain, but considering the guy I talked so said they had hotter options beyond the 262, I don't think there is any reason for concern. I suppose the grinds aren't really specific to a particular engine though, just a profile with no hard tie to the core it is cut on. He mentioned that their KC859 was based on/developed for a British application.
 
I asked for a custom grind ( intermediate ) and they replied :

. .001 lash difference will throw those specs out the window. The feeler gauges used to measure lash are not usually calibrated.

I do not really know what that means but I gather they prefer to stick to tried and trusted grinds .( the ones already in their system ).

I will run with the 250 s grind , you run with the 262 and we can post dyno results at completion to compare powercurves ( for future reference ) ;)
 
I'm surprised at the need for such a low DCR. I was under the impression that most engines make the best power between 7.5-8.5 DCR.
That is correct. But we are trying to stay with the ability to run junk gas. Best power comes w/ higher CR and better fuel.
 
Dropped by the machine shop today to see what's up. Seems their head guy was out sick for a week and is just getting back at things. Should get a call tomorrow with details. I revised the target chamber volume to 75cc, which should give a DCR between 7.25 and 7.3 I believe.
 
That is correct. But we are trying to stay with the ability to run junk gas. Best power comes w/ higher CR and better fuel.

With all the porting and polishing I figured you were after power. I am surpirsed however that a 2f would have detonation issues with a 7.66 DCR. Polishing the combustion chambers should help some. What sort of quench does a 2f have?

Have you guys read about singh grooves (and I know I'm probably going to get flamed for this)?
 
With all the porting and polishing I figured you were after power. I am surpirsed however that a 2f would have detonation issues with a 7.66 DCR. Polishing the combustion chambers should help some. What sort of quench does a 2f have?

Have you guys read about singh grooves (and I know I'm probably going to get flamed for this)?
The porting & polishing and polished valves and balanced rotating assembly and optimized ignition curve and bumped CR and so on... is all about maximizing efficiency. An efficient engine drives better and gets better MPG. A happy side effect of improving efficiency is more power to the wheels.

Singh grooves are still unproven. sometimes they work, sometimes not. There just isn't enough data to conclsively say what the best location/shape is (seems to vary w/ chamber design). So I have not been chopping up heads randomly to test the theory.

Sorry for the hijack, this is Doc's thread....:whoops:
 
Interesting... :hmm: I'll have to have a read through some of that.
 
Well, just called the machine shop to see what's up... Was expecting a call to talk about it the day after I dropped it off, heard nothing for a week...... when I dropped by, it sounded like their head guy had been out sick for a week..... another week went by without hearing anything, didn't return my call Monday...

But, sounds like the machining is all done, they are just waiting for springs to come in (tomorrow?) and it'll be ready to go. That's a nice surprise. :)


Tracking shows the cam has made it to Delta as well :)
 
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What springs?

Not sure, I'll find out when I pick things up (the one I talked to wasn't the one who did the work). I gave them a note sheet with everything I knew and wanted. I gave them the lead that there are short SBC valves that are supposed to work.

They were balancing the crank, installing (grinding) the valves, adding required valvetrain pieces and shaving the head to give the desired cc volume.
 
Started prepping for the coatings.... blasted the rocker tips (might give them a bit more), pistons and rod bearings. Need to do the main bearings, exhaust manifolds, ends of the push rods, chambers, valve faces and maybe the lifter faces yet. 100 grit Al Oxide, clean well, flush any contamination with Acetone, air brush the coatings and bake.... fingers crossed I get good coverage and adhesion.

No comments on the reuse of "wear" items please. A proper job of the bottom end isn't in the bank account at this time, that's one of the main reasons I've decided to give these coatings a try.

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cool, it will be interesting to see how well this coating works, and to hear how the coating lasts, do you think you can pull the pistons every oil change and take some pics for us?


No but seriously, you'll have to give feedback later down the road to let us know how its working, also what will your finish sanding be? 1000 grain?

Good to see some pics!
 
It might be worth it to drop the pan and check a couple bearings after a while. As for the pistons.... they'll stay put till the engine goes kaput. :hillbilly:

The coatings go on over a surface that has been given tooth and had "the pores opened up" with 100 or 120 grit sharp media. The DFL (dry film lubricant) that will go on bearings, piston skirts etc is oil retaining, moly impregnated and is supposed to be sacraficial (i.e. it wears down on contact rather than flaking off) when applied properly.

Here's one of their vids again: YouTube - Techline Coatings on No Speed Limit
Another showing prep and application: http://www.youtube.com/watch?v=8ZoZjUn9szs&feature=player_embedded
 
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Im just watching the video on youtube, and they do use it on bottom end bearings, I thought the coating would give too much thickness and wear down, but it seems like they have it figured out.

That is almost as crazy as your hairy vomit fish story ;)
 
Looks like our rebuilds are at the same stage currently .
The machinist asked for the head gasket last week to determine the cc of the chambers and calculate compression .
My engine has been sent off for balancing yesterday . My cam is also at Delta this week . ( shipping back to South Africa may take a few weeks though ) .
 
Dry film lubricants are quite popular in high performance racing applications. Many engine builders such as Cosworth even include Dry film coatings on their engine internals from the factory- to include lubricating coatings on piston skirts, oil shedding coatings on the inside piston dome's and coatings that attract oil on things like bearings.

pretty cool to see you putting them to use in a Crusier.
 

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