Michel The next step is to use a cylinder leakdown tester to see where the air is going in cylinder #3. Paul
Ok...1st thanks to all of you guys for your help. The car is parked outside as I type. It's heading east to spend the winter with my Dad and my brother. The carrier should be here in the next hour. Hopefully spending time with other members of my family will give my car a different outlook on things and increase it's appreciation for all the attention and caring it receives. Seriously, I will be off the board for a while. Other priorities, I will give you guys an update when appropriate. It's all good. My Dad and brother are both tech's...but they ain't touching my car without me around, guess I will have to do a couple of side trips over the winter. I will ask my bro to at least do the leakdown test when it car reaches it's destination.
I'd bet you a dollar it has more to do with valvetrain stability. Those fast Xtreme and XFI profiles are great for AUC, but wreak havoc on stability, longevity and quietness. As has been proven by dyno testing by JW, fast is not always better, specially if it won't follow the profile like it's supposed to.
I say leave the car alone till you get it into your new home garage... It runs now, just leave it as is till the move is over...
Ok, I have resurfaced!!!! Here is the scoop, I quit my big guns Corporate job in December. Cashed out of the city. Moved back to my home town of Bathurst NB. Bought a house on an acre with waterfront within walking distance to Dad's house and am the owner operator of my own business. In short, business, family and new lifestyle all exceeding expectations. Life is good. The Buick is back in the garage. Received following parts last week: 50232 crower cam, lifters, adjustable push rods, full gask kit, adj oil pressure regulator, shim kit for oil pump, a set of adjustable push rods and will be putting my old oil pump cover back on due to the poor quality of the replacement unit (side gear clearance issues.. ) We have the tool for the leak down test and will tackle that tomorrow. Hopefully we can move to the next step. My question, when I have #1 at TDC which other pistons will be in the same position? I remember someone posting this info some time ago but cannot find that post. Also like to know how other pistons will align with TDC. I know there is a sequence to save time...clear enough??
Welcome back to the Buick world. First things first because the wait is killing me now that you brought this one back up. When you get the cam you have in now out PLEASE, PLEASE post any numbers you find on it(usually on the end) so we can see if we can figure out what cam it is to know where you are going. That Crower cam seems like a good all around performance cam for the 300. Should work well with your setup. Hopefully the cam you have in was too big and then this cam will really perk up the low end torque. The way you described your idle it just may be. Pistons match up by firing order except one is moving toward TDC and the other is moving away from TDC. If the 300 has the same order as a 455 then it is 18436572. In that case 1&6, 8&5, 4&7, 3&2. Your best bet when doing leakdown or adjusting valves is just follow firing order because even if both pistons are at TDC the cam lobes are not at the same spot because one is getting ready to work the intake and the other is getting ready to work the exhaust. I marked my damper at 90, 180, and 270 because a piston is at TDC at all those positions. Makes it easier doing leakdown. I don't know if anybody mentioned it earlier but lift means almost nothing to the way a cam idles or its' cylinder pressure(generally speaking). Valve closing points, duration and lobe centers, which changes overlap, make the biggest difference.
Lk down test on all cylinders. #3 had 78% lkage (same cyl that had low compression), was blowing past rings. Removed piston. All looks good, only thing we find out of spec is ring gap at 27 thou. vs 10 thou per spec. That enough to cause issue? If further doubts all we can do is have the cyl bore checked to make sure it is not out of round.We will swap out cam tomorrow. Need to order rings. Oh well!
Ive run over .040" ring gap on large nitrous motors and they leaked down at less thna 2 percent when new So no.That ring gap isnt an issue
Well boys...not good news. Block needs to come out. Cam bearings are shot....valve seats poorly grinded and not seating properly, who knows what else we will find. The number on the cam we removed was CH926EX0. The guy who built this engine is Ceasar Desilva, he owns a shop called Mississauga Engines in the west end of Toronto.STAY AWAY!
