You mention using 30wt for break-in. What do you plan on running afterwards? Also, what brand?
70 dart 470 ci drag car build.
- Thread starter MOPARMAGA
- Start date
-
So the engine as it sits now.
12.8:1 compression
471 cubes.
4.375 bores.
3.915 stroke.
6.700 rods
Pistons are abraidable coated and they have total seal gas ported rings.
Trickflow 240, gasket matched which added .400 CSA. Heads were surfaced .080 to a 65 cc chamber (were 78).
Tunnel ram gasket matched and further ported and burr finished.
2- 850cfm blp carbs.
Camshaft is solid flat tappet 264-268 solid flat tappet, retarded 2° to center overlap triangle.
1.6 rockers and I believe the cams lift is .664-.674 on 106 icl. So a pretty small cam
I think that's all.
Last edited:
Well I was going to run vr1 because it's available locally 10-30 and we'll see because Tim thinks it's going to kill power. I don't think so but we'll see.
Yea we know. lol
I bet he's trying to get you to use Torco products.
Yes, he'd recommend that exactly but he isn't paying for it.
Nothing but VR1 for me. Besides, I already have 5 jugs of it.... lol
Yeah, the stuff works and works very well.
Yep me tooHe's out there on some.
Matts440
Well-Known Member
You have built one awesome motor there, will be fun once you get it into your car. Awesome job. I run VR1 in my setup, good stuff.
More testing in the morning.
We have power valves to change, step down to 66 jets from 68 and 64s after that.
If that doesn't lean it out we'll block the bottom emulsions.
If that doesn't work, I'll put a 350 cfm 2 bbl on it.
I'll let you guys know what happens.
Oh and thanks for following along!!!
We have power valves to change, step down to 66 jets from 68 and 64s after that.
If that doesn't lean it out we'll block the bottom emulsions.
If that doesn't work, I'll put a 350 cfm 2 bbl on it.
I'll let you guys know what happens.
Oh and thanks for following along!!!
Matts440
Well-Known Member
Thats the best thing about this place lots of available advise, help and support.
Didn't do much today but went over to Tim's for a few hours, he said it was his birthday. A couple days ago we checked my 1st oil filter for signs of bad news and none was found.
I changed my oil and turned up my oil pressure 10 psi today. Tim was up early and blocked my lower emulsions and changed the pv to 4.5 we then messed with the fuel pressure.
It didn't run right after that. I think the gauge is giving a false readings.
So we made a pull and a second and it really wasn't happy sounding so we pulled the valve covers and looked at the plugs.
The problem was number 1 plug was fairly loose. While the valve covers were off we ran it on the starter and everything looked fine but some of lash had tightened up or I didn't get it right when it was on the stand or now the chain has stretched a little and now it's lashed to where it's supposed to be.
I left and tim is working on my distributor because it's advancing way to quickly he's shooting for 24 initial and 30 all in. So we're still working on leaning out the afr.
Other good news all cylinders were at 180 psi on slow starter ( low batteries)
Loose spark plug was a 3 HP loss lol.
I changed my oil and turned up my oil pressure 10 psi today. Tim was up early and blocked my lower emulsions and changed the pv to 4.5 we then messed with the fuel pressure.
It didn't run right after that. I think the gauge is giving a false readings.
So we made a pull and a second and it really wasn't happy sounding so we pulled the valve covers and looked at the plugs.
The problem was number 1 plug was fairly loose. While the valve covers were off we ran it on the starter and everything looked fine but some of lash had tightened up or I didn't get it right when it was on the stand or now the chain has stretched a little and now it's lashed to where it's supposed to be.
I left and tim is working on my distributor because it's advancing way to quickly he's shooting for 24 initial and 30 all in. So we're still working on leaning out the afr.
Other good news all cylinders were at 180 psi on slow starter ( low batteries)
Loose spark plug was a 3 HP loss lol.
Also, I think my tiny family of wife, cats and dogs are on the upswing. 3 crap things happened back to back to back.
Pup was hit by the truck, amputated leg ( she is doing great. My wife broke a rib last week and I somehow released my little kid chicken pox bs out as adult bs worse as shingles and I'm only 45 . But besides being in massive pain and same with my wife were helping each other out and are grateful.
Pup was hit by the truck, amputated leg ( she is doing great. My wife broke a rib last week and I somehow released my little kid chicken pox bs out as adult bs worse as shingles and I'm only 45 . But besides being in massive pain and same with my wife were helping each other out and are grateful.
MidnightSwinger
Well-Known Member
Im sorry to hear that man, but I’m glad you are on the upswing and staying positive.
Thanks Jared.
Do you have a stand alone o2 you can beg, borrow or steal? Place it in the side that isn't working and then swap sides with the dyno o2. O2's offen times won't read the same from side to side but should read the same on each side with a no change test. Also low rpm readings with an o2 can sometimes be inaccurate.
Do a couple of no change pulls or just partial pulls if the tune doesn't look right. This might give you either more or less confidence in the readings you're getting now. Not having confidence in the data you need to help you tune makes it tough. Especially on a "new to you" system you're still sorting out.
If you have good fuel flow data and air flow data you should have an air fuel ratio channel to compare to your o2 readings. The numbers might not be exactly the same but they should trend in the same direction ( at higher rpms).
Remember that your o2 reading even if accurate is just an average of four individual cylinders in a collector. And based on the position of the o2 it can be influenced by one cylinder more than another. Also air fuel ratio as calculated by an air flow meter and fuel flow meter is going to be an average of all 8 cylinders.
Spark plug reading, individual EGT temps or individual o2 readings can help sort things out on a individual cylinder bases.
I'm interested in how you are using the oscilloscope on the dyno. I used one years ago when doing tune-ups but haven't used one on the dyno. Are you using it durring a pull or under load?
Do a couple of no change pulls or just partial pulls if the tune doesn't look right. This might give you either more or less confidence in the readings you're getting now. Not having confidence in the data you need to help you tune makes it tough. Especially on a "new to you" system you're still sorting out.
If you have good fuel flow data and air flow data you should have an air fuel ratio channel to compare to your o2 readings. The numbers might not be exactly the same but they should trend in the same direction ( at higher rpms).
Remember that your o2 reading even if accurate is just an average of four individual cylinders in a collector. And based on the position of the o2 it can be influenced by one cylinder more than another. Also air fuel ratio as calculated by an air flow meter and fuel flow meter is going to be an average of all 8 cylinders.
Spark plug reading, individual EGT temps or individual o2 readings can help sort things out on a individual cylinder bases.
I'm interested in how you are using the oscilloscope on the dyno. I used one years ago when doing tune-ups but haven't used one on the dyno. Are you using it durring a pull or under load?
I should have remembered to post that both afrs worked the last couple pulls.
You make some points that made me think.
We have a 6inch exhaust system that lays on the ground with big semi tractor mufflers on the end.
There's so much exhaust pulse reversion coming back out of that pipe that's hooked to my collectors so there's air definitely getting backed up and the point of the 02 sensor
In my opinion the reversion at low speed can sometimes make the o2 reading unreliable. I don’t know that as fact. This can be affected by the length of pipe behind the o2 sensor too. I see lean spikes in the o2 curve at lower rpms that don't coincide with the air fuel ratio as calculated by the airflow and fuel flow meters. There could also be others reasons for that too.
All that said about how unreliable o2s can be I have found them to be very helpful (a real time saver) and for the majority of the time a reliable indicator of the air fuel ratio.
This is from Jere Stahl's (of stahl headers) website. I don’t know if the site still exist. There was lots of helpful information about dynoing on his site. I copied it into my dyno book when researchinghow to build my dyno. Here is what he had to say about dyno exhaust. For what it's worth.
I'm not saying what you're doing is wrong I'm just presenting what Jere had to say about it.
-
