IHI

iTrader: (1)

Learn from my brain fart please! I did this earlier this year when I still had my 305 and wanted a hotter cam, so naturally installed new vavle springs-while it was still in the car. Took my compression tester gauge apart, bought an air chuck and some couplers so I could screw the spark plug end into the head and hook the air hose to the other side to keep the vlaves from falling into the cylinders. It just would not hold the valves up even at 135psi-WTF. Everybody else said it works and it did'nt for me. Luckily there was enough tarnish on the valves to keep them high enough to grab them with needle nose vice grips to keep them from going all the way down. Jump foward 5 months, changing cam and springs in buddies newly aquired 454 bone stock 42,000 original mi. out of 78 Suburban, had another fella over doing it cause he has all the fancy tools, but forgot the air hose thing, so I broke out my trusty gadget I made and handed it him. Screwed it in, applied air, no air going into the motor-then he asks what it origianlly was then, "don't compression testers have a one way check valve in them?" DUH!!! Had to get out the valve core removal tool and it actually screws in from the cylinder side of the fitting-where the compression from the engine would go in. So from my brain fart I hope some lucky person reads this and learns a lesson.
P.S. 305 blew up the next day as a keeper found it's way into the motor and with an non-functioning temp idiot light also overheaded and locked it up-no biggy as I got the reason to build my 355. The 454 in buddies car made it's first pass down the strip and at the 1/8 mile lost power. Tore the intake off and found 1 lifter not lifting, pulled it out and 1/4" of the bottom sheared off. Lunati hydraulic cam by the way, called summit told them what happened, they want to get the cam and lifters back as Lunati had a "bad" batch of lifters-nice they let the guys buying parts know that, and told my buddy he has an open account with Summit with 10% off all the parts to have the 454 rebuilt. The oil looked like glitter, plus they're crediting him for the cam. Here we are drag racing and he's on his 3rd motor in 3 weekends just trying to finish the season, first motor lived longer than expected before valve snapped off and danced with the #7 piston turning the oil pan into a metal catch basin, the 454 you just read about, now got a bone stock 400 out of a 75 Caprice that pops and bangs after 4800rpm. Fun stuff, now if this was mud pack racing this kind of luck would be expected, not with drag racin.

AlkyIROC

Sounds like my race season's. Last year I blew up 2 big blocks by breaking the heads of valves. They punched holes in the heads and cracked cylinder walls.

This year I only floated the valves and bent 3.

IHI

iTrader: (1)

Today they're running 1/4mi. races, then Sunday switching to 1/8 mi. preping us for Nationals and that's all my buddy is wishing for os the 1/8 mile right now. He's so frickin timid after this motor changing stint, he would'nt do ANYTHING to the 400 he has in there now, I kinda understand cause it's getting old burning midnight oil everyweek. I want to drop a Big Block in mine before next season cause ALL of the street class down here will have them except me, but I've talked to a few people and they said dollar for dollar you can make a bullet proof small block that will beat the Big Blocks, dollar per dollar. I'm kinda at odds on that issue cause it's hard to beat cubic inches and, not only that they look a hellava lot better when you pop the hood.

ede

my compression tester is snap on, the hoses don't have a check valve in them, i'd guess if it does have a check valve it's in the gauge. i did buy it used so i guess there's a chance another owner took it out.

AlkyIROC

There's nothing saying you "have" to have a big block. There are 2 other local racers here. One has a first gen with a 377 and the other has a second gen with a 350. They both run close to what I run.

92RSFivePointSlow

IHI, another way I found to chanhe springs while heads are on block is to crank the motor till the piston is at TDC. The two valves wont go down since the piston will prevent that. Change your springs and turn it to the next piston in sequence. Seems alot easierthen using air to me...

johnsjj2

Before I had an air compressor, I bought a lenght of small diameter rope. Shoved it in the spark plug hole with the piston near BDC. Then rotated the engine until it wouldn't turn anymore. Worked great, but it was time consuming fishing the rope in and out of each hole.

jimmy_mac

yes time comsuming is the key there. I started using the rope method and quickly found out it could take a while. So I to grabbed the hose off my compression tester and removed the valve with my fancy chrome caps on the wheels on my bike. Moving from cylinder to cylinder with the air hose is fast.