1987 Monte Carlo SS Build - Aka Project Grown

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Pro86tourn

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Apr 26, 2020
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So had the car on the dyno for the first pulls... all tuning done by myself which I certainly am not a pro.

AF - 12.75 and the stumble I have yet to solve in the carb is shown on the graph.

All in all super happy this is with a crap victor. Jr baby intake and stock crappy worn engine mounts as well as crunched headers to make them fit! So a few more ponies left to be found with a few more tweaks and getting the carb right and bigger intake!
 

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64nailhead

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No AFR gauge/sensor at the dyno? Once you determine if your stumble is a lean or rich bog, then fixing it becomes simpler.

No matter with that though, nice numbers. Congrats!

Edit - forgot to mention, Fleming is correct about the garbage you were told about the PCV, but a fresh motor that you want to last for a bit needs some form of crankcase evac at high vacuum conditions IMO. Either a vac pump or PCV.
 
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Pro86tourn

Apprentice
Apr 26, 2020
90
136
33
No AFR gauge/sensor at the dyno? Once you determine if your stumble is a lean or rich bog, then fixing it becomes simpler.

No matter with that though, nice numbers. Congrats!

Edit - forgot to mention, Fleming is correct about the garbage you were told about the PCV, but a fresh motor that you want to last for a bit needs some form of crankcase evac at high vacuum conditions IMO. Either a vac pump or PCV.
Yes Dyno had AFR and the car does as well.. 12.75 WOT..

Stumble is lean spikes to like 18 on initial tip in, once on main jets its fine. Ive tried a number of different squirters, power valves no differences...

Spoke to Mighty Mouse and they advised each valve cover to the catch can with a breather is more than fine or add an additional line to the intake which I will have to figure out and do to get rid of the fumes. Right now I am getting tons of oil in the catch can as my high pressure/high volume pump pushing it through at WOT.

But hey.. just things to work on!
 
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64nailhead

Goat Herder
Dec 1, 2014
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Upstate NY
Yes Dyno had AFR and the car does as well.. 12.75 WOT..

Stumble is lean spikes to like 18 on initial tip in, once on main jets its fine. Ive tried a number of different squirters, power valves no differences...

Spoke to Mighty Mouse and they advised each valve cover to the catch can with a breather is more than fine or add an additional line to the intake which I will have to figure out and do to get rid of the fumes. Right now I am getting tons of oil in the catch can as my high pressure/high volume pump pushing it through at WOT.

But hey.. just things to work on!
More pump cam meaning needs more fuel on tip in. Whatever as to be done. Power valve should have nothing to do with it on tip in. If squirter size has no positive effect and it's still reading lean, then lean it out a little. It is extremely possible that you have it so fat that it will actually read lean on an AFR gauge - extremely common due to the excess fuel is not actually burning.

Filling catch cans is caused by one of two things, either the deflectors in the valve covers aren't deflecting the oil spray or you have a bunch of blowby due to poor cylinder seal. The oil pump has zero to do with the amount of oil in the catch can.
 
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Pro86tourn

Apprentice
Apr 26, 2020
90
136
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More pump cam meaning needs more fuel on tip in. Whatever as to be done. Power valve should have nothing to do with it on tip in. If squirter size has no positive effect and it's still reading lean, then lean it out a little. It is extremely possible that you have it so fat that it will actually read lean on an AFR gauge - extremely common due to the excess fuel is not actually burning.

Filling catch cans is caused by one of two things, either the deflectors in the valve covers aren't deflecting the oil spray or you have a bunch of blowby due to poor cylinder seal. The oil pump has zero to do with the amount of oil in the catch can.

50cc pump, Prosystems had 45/45 for squirters... I dropped to a 35 car wouldn't get out my driveway, went up to 37 and same lean stumble.. maybe slightly better if any from 45.

Yeah, certainly am getting more then I would like.. 3/4 cup of oil after 1000kms of hard beating on the car. Fresh motor shouldn't have any blowby.. maybe I switched to synthetic too soon? The first 300-500kms were on conventional oil.

Im at 35ish psi idle, 50 psi cruise, 75 psi + WOT oil pressure.

Also,.. car doesn't blow any smoke out the tail pipes.
 
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64nailhead

Goat Herder
Dec 1, 2014
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Blowby is what it is. I can't speak to NA stuff, but I know about boost.

Add oil if it needs it and empty the can as needed. My son's motor needs what it needs. Beating on it will require a can draining every couple of tanks of fuel where easy driving will go 5-10 tanks of fuel. Drag stip requires a draining after every 8 runs.

I'll end my carb advice with 'I hate carbs' lol.

Good luck :)
 
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Tony1968

Royal Smart Person
Supporting Member
Jul 1, 2018
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I don't think it's blowby. You have a stroker crank and are creating more crank case pressure than normal.
The pressurized oil mist has to go somewhere
 
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