Pick the "Collective Brain" of the site :)

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sc racing
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Re: Pick the "Collective Brain" of the site :)

#16 Post by sc racing » Wed Mar 17, 2010 9:11 am

427belair wrote:Something to think about. I am far from an expert, but my nova started out by running times similar to yours. Without doing anything to the engine I managed to reduce my ets from low 10.6s to 9.90's with suspension work and seat time. Learing launch rpm, shift points ect. It seems like every race it went a couple .0x faster.
Thats the best advise right there^^^
You dont have a lot of track time Scott, some cars just run great 1st time out ( not many) most take dozens,or hundreds of passes to get full potential. If your worried about your blow by do a leak down test before pulling it apart if its really bad then move forward with your plan if not.....off to the track you go and test,test,test :mrgreen:

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sverbus
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Re: Pick the "Collective Brain" of the site :)

#17 Post by sverbus » Wed Mar 17, 2010 9:52 am

Well, originally when I started building this motor/combo I had plenty of money...then with broken axles, rearends, tranny's and drive shafts, that dwindled quickly. As I know you have all been there before. The fella that did the heads/intake has a great reputation of being able to really make heads flow better and matching each part of the head. BUT I do agree, that the use of technology and such with a flow bench would be awesome. And I may take Keith up on his services and just pay to get the heads really worked and flowed. THEN I'd have the numbers for a cam, AND then I can know that I"m getting out of the motor what I should, and then go spend some good time at the track.

Mr. Chance definitely agree's that my launch rpm for my power curve is WAY to low...but anything higher and it pushes the car. SO, disc brakes are also getting done this year. So that will make a big difference (and be great to be able to stop so much better) :) lol

Guys thanks so much for the advice and info...I AM going to Chassis dyno it when it's back together.

SC,

After beating up the pistons and cylinder walls for 4yrs on the street and track, I simply want the ease of mind looking inside the motor and making sure all is well. After we gap and check the pistons in the block and IF everything is ok, it will stay together. BUT if it's all loose, then what I mentioned in above posts will get done.
'70 Nova
434 small block
Best so far of 10.51 @ 131mph with a best so far 60' /1.46

sc racing
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Re: Pick the "Collective Brain" of the site :)

#18 Post by sc racing » Thu Mar 18, 2010 9:21 am

You cant launch at a higher rpm because you dont have a trans brake, I still dont see how it will help you if your current stall speed is higher than your launch rpm. Lets say your converter will flash to 4000 whats the difference if you hold it at 1500,1800,2500 ? Your car will still leave the line at the same rpm right . Maybe Im way off in my way of thinking but Ive seem many footbrake cars go faster with lower launch rpms.It may be part of your problem every car is different but your et/mph are pretty close its not like your going 10'70's at 135 mph so I just dont see a big gain there.
Even if your tolerances are in spec you can still have a lot of leakdown. But if its all good just re ring it and go play.Good Luck

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invegarating
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Re: Pick the "Collective Brain" of the site :)

#19 Post by invegarating » Sat Apr 03, 2010 7:55 am

Hey Scott,

It is strange that your best et and mph is exactly the same as what i got out of my 230 pro-1's but i have a vega so i am maybe a little lighter than you,but i did have some work done on mine also,but,when i had them flowed before any work was done they were 289 cfm on the intakes,i did not have a fortune to spend so when the flow numbers got to 303 i had him stop,but that should give you a ballpark figuire for your flow numbers.

Just a side note the cam that was in it was 106 lda,.640/.660,260/270@.050" with comp pro magnum 1.6's and it would stall on the transbrake to 3800 rpm,oh yea this is a street car also.

Two years ago i got a set of AFR 227 competition ported(cnc'd) heads and borrowed a circle track 950 hp alcohol carb and right off the trailer it went 9.99@127 coasting across the stripe...everything else was the same

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sverbus
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Re: Pick the "Collective Brain" of the site :)

#20 Post by sverbus » Sun Apr 04, 2010 9:42 pm

Well, got the motor out of the car this weekend finally and got it tore apart. Just as I thought, we were definitely getting blow by somewhere. Amazingly enough, the pistons are STILL only 5thousandths between them and the walls...BUT the blow by is coming from the rings, which are plain worn out. They are over 30thousandths worth of gap.... :shock:

No wonder I was getting blow-by. The heads are in great shape inside, running a bit fat but nothign I can't remedy with some tuning (it had also jsut been idling alot in and out of the trailer and garage before the tear down.)

So, I doubt I will be replacing the pistons...Gonna just order another set of good rings from JE and just go back at what I got. I AM going to be sending my heads to K-Star Performance and spend some money getting them ported professionally and I'll make a cam change. I had a few rollers getting chewed up on my Harland Sharp rockers which put some nasty ugliness on the tops of a few valves SO I gotta get a few valves and I gotta replace some rockers. I also noticed the last two years that I didnt like how much angle was getting put on my rockers to the intakes so I'm going to take this opportunity to get offset intake rockers from Harland and go from there.

Questino, what is the BEST way to measure for how much offset I need? I'm staying wtih my Dart Heads that are 23* and they have the 2.08/1.60 valves. Anyone suggest/advise a different rocker? I'd like to hear some idea's. I like Harland Sharp, have ran them on my motor's since i was 16 and this is the first set that I've seen some wear on the rockers. MIGHT be because the cam is so big and so much seat pressure.

So, gonna be busy these next couple weeks....gotta get everything cleaned and back from machine shop and back to PA to reinstall.

Scott
'70 Nova
434 small block
Best so far of 10.51 @ 131mph with a best so far 60' /1.46

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ytnova
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Re: Pick the "Collective Brain" of the site :)

#21 Post by ytnova » Mon Apr 05, 2010 9:32 am

Me personally, I will never run stud type rockers again if possible. By far, one of the best investments I have made was putting a shaft mount setup on my bbc, you just can't beat the reliability. I went with t&d, but jesel and some others are just as good. I love the fact that I never have to adjust the valves, when they are loose, something is wrong! And setting them up and getting the right pushrod length has never been easier. If you add everything up, studs, rockers, stud girdle, etc. you will find that it is not much more to go with a shaft mount system and it would probably fix all of your problems.
I am not really sure what the question is, but I am pretty sure the answer is Big Block.

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sverbus
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Re: Pick the "Collective Brain" of the site :)

#22 Post by sverbus » Mon Apr 05, 2010 10:44 am

HAD I thought this far ahead when I bought everything for the heads I would have just kicked a few hundred more in and got a set of T&D's or something..but I didn't and now I"d never get enough out of my used stuff to be able to get a shaft system..and they aren't cheap (and for good reason) so I will have to stay with my stud setup.
'70 Nova
434 small block
Best so far of 10.51 @ 131mph with a best so far 60' /1.46

sc racing
Posts: 1773
Joined: Sun Jun 11, 2006 1:45 pm
Location: Sahuartia Az

Re: Pick the "Collective Brain" of the site :)

#23 Post by sc racing » Tue Apr 06, 2010 8:58 am

You only need offset rockers if the intake stud is moved over away fron the port. Dart can tell you if your heads are offset. Check with Harland Sharp about the max spring pressures their rockers will handle, your lucky none of them came apart. If your rings are worn that bad I would think whoever did the machine work didnt hone the bores correctly for the type of ring used. I just noticed your heads only have a 2.08 valve, if you need a few new intakes and are porting the heads you might want to look into a bigger valve if the head porter knows what hes doing he should be able to figure out what size is best along with the csa,throat size, flow #s etc etc.

waterdog
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Re: Pick the "Collective Brain" of the site :)

#24 Post by waterdog » Wed Apr 07, 2010 7:56 pm

I've always used Harland Sharp rockers and never had any problems with them. My latest heads weren't agreeing with stud rockers, so I switched to T&D's and those suckers are nice. Walt
1970 Nova SS 3580lb, Shafiroff 434 na, 9.94@135.8

427belair
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Re: Pick the "Collective Brain" of the site :)

#25 Post by 427belair » Wed Apr 07, 2010 10:37 pm

Defenitly get the biggest valve in there you can since you getting head work done and you need a few new valves anyway.

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invegarating
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Re: Pick the "Collective Brain" of the site :)

#26 Post by invegarating » Sat Apr 10, 2010 9:54 am

I have offset Harland Sharps on my AFR's that have a .050" offset but on my pro-1's i had regular (no offset) pro magnum rockers,I think the valve in the pro-1's is moved .030" but you may want to check that with Dart or just check with Harland Sharp for there recommendations on that head,if you are going to stay with stud rockers the new comp. cams gold rockers are very nice,and the comp. pro magnums are as well.....in my opinion they are much better than the Harland Sharps

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