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Ok, another odd thought here after reading the last few posts. I have a friend I'm working with and his car is running rich. So the car keeps adding IAC counts and trimming fuel back at the same time. So it's actually running on more load until the AFR is right.
You might want to activate your fuel trims and then use your trims to dial in VE and MAF in idle regions. If you did need fueling adjustments your vacuum should improve when it's done
thanks darth! I appreciate you commenting and giving me ideas.
The car is basically idling hot 178/180*F with an AFR of 15.5:1 pretty steadily. This is around 700rpms at 55kpa and 21.5* base idle timing. I'm commanding 22 and it pulls .2-.5* for whatever reason. I had it idling at 14.5-14.8:1 but read that cams with more duration trick the motor 02s into thinking it's leaner than it actually is... so to run it at 15.5:1. The leaner idle isn't going to hurt anything anways. The issue I have with activating the STFT and LTFT is that when I use the 02 sensors it runs worse it did when it was a stock motor and I tried to activate them a few tunes back and it ran like poop. 02s are cheap replacements more for just plugging the holes.
Ive thrown more fuel at it, and bumped timing to 24* and it seemed to run worse at idle. I think 22* is going to be my max but may take it down to 20* which is where I had the stock cam running. Bumping the timing and fuel did nothing for the vacuum FWIW. I'm not sure why but it seems to make it run worse with more timing. I've read 20-24* base timing for mild cams. Think I have it at 20* WOT. I'm also running a custom OS in HPT using a 2bar Speed Denisty OP System do I don't have a MAF anymore and just doing it all SD. It's worked great thus far. So all my fueling comes from the main VE table and other tables like PE, boost enrichment, cranking and afterstart. I can post a log and the tune if u want to take a look.
The good old news is i free reved it to like 3k and throttle seemed great and didn't want to stall coming back or hang. But a very light blimp caused a slight stumble on the way down. Lifters are still pretty quiet from the sound but the supercharger whine makes it harder to hear lol. I was still getting over 3/4 turn preload on most (more around 7/8-1 turn with the 7.375s) and I want to be around 5/8 turn preload so I'm going to go get some 7.350 and mix and match where need be. I'm looking at some comp cam magnums 7.350 for $104 or trick flows for $99.
EDIT: I forgot to mention IAC counts. Mine are pretty steady and in the 40-50 range at warm idle at 700ish Rpms.
I also don't put the car in closed loop or even activate the STFT or LTFT as I find it runs better that way.
You've got issues going on, plain and simple. This is not normal.
Originally Posted by Darth_V8r
I bet if you measure all 16 valves you get that much variation due to stacked tolerances. Mix and match the longer and shorter ones where they need to go and your preload might actually end up BETTER!
You've got issues going on, plain and simple. This is not normal.
Wow........
agreed! But I think it has to do with the cheap 02 sensors more than anything. I'm talking like $30 for the pair new lol... made in China! The OE ones are like $100 a pop or something crazy. Just like a ACdelco IAC is $100... and a ACdelco TPS is like $50. Incredibly expensive for such a small part.
Well I made myself a adjustable pushrod from a old stocker. Took a whole 10min lol.
I set it for 7.350 gauge length and measured. here are the results vs the 7.375 BTRs.
#1 intake
BTR: 1-1 1/8 turn preload or .078-.08775"
7.350: 5/8 turn preload or .04875"
#1 exhaust
BTR: 3/4-7/8 turn preload or .0585-.06825"
7.350: 1/2 turn preload or 0.039"
so if I get an actual gauge length of 7.350 then my preloads will be right on the money or close enough to it. Anyone have any experience with the comp magnums? I hear they are dead accurate from some reviews. Also trickflow is like $100 but I heard there 7.375 was long just like the BTRs.
Well it's never easy. Got off the phone with Michael tooley from BTR. Gauge length will be longer than the pushrod length as it rests on the ball. So here's the problem. Basically all my gauge length measurements will be .018" too short. So a 7.350 has a gauge length of 7.368. Then of course you have your variances between pushrod manufacturing which was .008" from the shortest to longest in my BTR set.
So now I'm stuck if I should go too short or ok the brink of too long?
i set my adjustable to 7.368 gauge length (7.350 pushrod) and did preload on both intake and exhaust and got 3/4 turn (0.0585) on the intake and 5/8-3/4 turn (0.047-0.0585) on the exhaust.
I then set my adjustable to 7.343 gauge length (7.325 pushrod) and did preload on both intake and exhaust and got 3/8-1/2 turn (0.02925-0.039) on the intake and 3/8 turn (0.02925) on the exhaust.
So with the 7.350 I'm around 5/8-3/4 turn preload on both and barely under .060 preload. Or go with the 7.325 and go with .029-0.39 preload.
agreed! But I think it has to do with the cheap 02 sensors more than anything. I'm talking like $30 for the pair new lol... made in China! The OE ones are like $100 a pop or something crazy. Just like a ACdelco IAC is $100... and a ACdelco TPS is like $50. Incredibly expensive for such a small part.
OEM are 25 apiece on ebay, Ive bought them several times. Bosch 13111 is the ones I use.
I have a 5.3 iron block with tsp 5.3 heads with morel 5315's. I have my preload around .035 give or take a little and my motor is dead quiet. I have the btr pushrods and mine varied like yours. Since they are hydraulic you have some play.
Here is what cstraub told me a while back, heads will grow .006 to .008" when the engine is warm. This reduces preload. On an aluminum headed engine/iron block Morel wants around .045" of pre-load
I have a 5.3 iron block with tsp 5.3 heads with morel 5315's. I have my preload around .035 give or take a little and my motor is dead quiet. I have the btr pushrods and mine varied like yours. Since they are hydraulic you have some play.
Here is what cstraub told me a while back, heads will grow .006 to .008" when the engine is warm. This reduces preload. On an aluminum headed engine/iron block Morel wants around .045" of pre-load
What size pushrods did you go with?
Good to hear! I decided to go with the 7.350 BTR pushrods after speaking with Michael Tooley at BTR for a while. Seems I should be at .05-.06 preload with those and if the head grows another .006-.008 it will drop me down into the perfect range.
Michael did tell me that the morel 5315 are very "finicky" and sensitive. Preload and Oil weight are very important since they are so sensitive. Recommended that I dont change my oil weight (mix of 10w30 and 20w50) as hes had customers drop a lifter after just changing the oil viscosity.
I should have the pushrods tmrw and hopefully fire it up over the weekend.
Well got my 7.350 pushrods today. And this set was SPOT on! All 16 were very close to each other. And after measuring I installed them and they all are done. I got mostly just about 3/4 turn on all of them but ranges between 3/4-5/8 turn.
cant wait to crank this bad boy over and see how she sounds. This hopefully means I can get the car off the stands and back on the ground. Install the hood and get to driving and tuning this thing.
Pics show the 16 pushrod spread with measurements. I know they said 7.368 but all of these came under that.
04-16-2017, 10:21 PM
