Getting my new F13 (112+4) cam after I get my old one replaced. I have a set of AFR 205's ready to bolt on. They are the standard 66cc chambers without any milling yet. I plan on a 11:1 CR. I have a few questions...

Will my PTV Clearance be ok with .030" shaved off the heads?

Should I use GM head bolts or ARP bolts or studs?

What will my pushrod length be? Or will I have to check that?

I plan on running a .045" gasket...should I run a Cometic or something else?....I have heard of these having sealing problems...what do you think?

Any other info will be appreciated on this setup.

Thanks - Josh

 

I would always measure the P/V clerance.

I LOVE ARP head studs.

Yes check your pushrod length, though I think 7.40 would be pretty close. Others will chime in here....

Going to a .45 gasket isnt going to make much difference IMHO but others may disagree...

 

Actually, tight quench is your friend. You want it as close as you can. I'd recommend a .040" Cometic gasket. Don't worry about the leaking, you'll be fine. 7.400" pushrods should be close. Glad to hear you're going to mill the AFRs .030". Compression is your friend too. With a tighter quench, you should be able to run around 11.5:1 static compression without octane issues. I love the ARP head studs, especially since I've had my heads off once already (swapped to 225s). Your P to V clearance with a .030" should be OK with a cam that small. The free drop on the 205s is better than a stock head.

 

You'll want to mill .036". You lose 1cc for every .006" on a flat mill. P to V shouldn't be a problem. I would use .045 Cometics. That pushrod length should be OK as long as you have about 1-2 turns of preload set from zero lash.

I have ARP studs and they are great!

 

Assuming .007 out of the hole with .030 mill (61cc chambers) and .040 Cometics your DCR looks like approximately 8.93 Going to a .036 mill and .045 Cometics gives you a DCR of 8.94ish.... Good luck on pump gas and be prepared to pull some timing.... I have went as high as 8.6 DCR on 93 octane. Your IATs and BARO will also affect whether you get knock or not.

Are you trying to stay away from fly-cutting???

I would like to see more discussion on DCR limits vs. octane...

Again Good Luck,

 

Well I'm kinda confused here...I called AFR today and talked to Jason (if I remember correctly). He said that they recommend the .040" gasket, then knock the mill down to a .025". I went ahead and ordered the .040" cometic gaskets and I intend to mill them .025" now. I then called Futral and talked to them and they seemed to think that the PTV would be extremely close and wouldnt give me a definate answer if I were to use the .040" gasket and mill .025". I can live with 11.0:1 CR cuz I wont be getting it dyno tuned for awhile...just laptop tuned by myself and a friend.

I dont want to flycut the pistons, I want to get this thing back together ASAP as it's a daily driver. Also, I bought a PR length checker so I plan to check that length after I get the heads bolted down. Also, I have the 72432 Lunati lifters going in with the new F13 cam...what type of preload should I set? .050? .100? Or should I call Lunati and ask them? I want to be absolute certain that everything is on order so I dont have to rip this all out again.

So basically if I want a 62cc head, I mill .024", use a .040" gasket, and based on stock pistons with .007" out of the hole, I can expect a 11.0:1 CR right?

So...Are you all sure this will work (PTV) if I mill .024 and use a .040 gasket?

 

Here is some info from Futral.... post #32

https://ls1tech.com/forums/dynamometer-results-comparisons/327005-afr205s-f13-dyno-440-420-sae.html

Sooo going with the above info and using a .040 Cometic gasket would put your intake clearance to approximately .072, too close IMO. If you really want to know you are going to have to mock-up the entire setup and test for yourself to be absolutely sure...

 

Well...I think I will get it mocked up after I mill them .024"...if it's too close, I'll flycut the pistons...I'd really rather not...but I'll do what I have to do I guess.

 

If you're even considering fly-cutting the pistons, I would go for the big mill. Get your chambers down to 59-60cc and run the .040" Cometic gasket. With a .036" mill and thin gasket, 7.400" PRs will be good.

 

i was told with mine, im having them milled down to 62cc(from 64cc now) with a cometic 40 gasket that the biggest cam i can run is the 224/228. But i want a slightly bigger one than that, maybe like a tr230 or something like that.

 

This is pretty much what I'm having done. It should be getting tuned tomorrow. I'll post the results.

 

yeah let me know, i wanna see what you put down.

 

GTO1_Ohio

You better have it ready for the 24th!!

 

I've been looking into this setup ever since the 205's came out. I also like other heads, but I've always heard this would be really tight and flycutting might be in order.

My question is: Has anyone run a F13/AFR205 combo? If so, how much milling and did you flycut the pistons?

Also, theoretically, would one make more power by going the flycutting pistons route, or by trying to squeeze the setup together without flycutting? Would this affect the "under the curve" power at all?

 

Oh no problem....I only dropped it off two weeks ago.

....really I do expect to pick it up this weekend.

 

Please let us know what you're final pushrod length will be when decided.

 

I ran a F13 with AFR205s, 62cc (.024 mill) with .045 Cometics. A good street racing TQ setup. 440/420 SAE without a FAST 90/90 setup. I measured and it was under .075 on the intake side... Too close for me the deal with so I fly-cut my pistons.

Just fly-cut and be done with it....

 

Here is the info on my pushrod length...ended up ordering a 7.325" pushrod giving me a .050" preload.

https://ls1tech.com/forums/generation-iii-internal-engine/484155-so-i-measured-pushrod-length-need-input.html