408 stroker with weird compression
Thread Starter
Staging Lane
Joined: Dec 2015
Posts: 71
Likes: 2
From: Roy, Utah
408 stroker with weird compression I could use some advice. I had my local machine shop shot peen, hot tank, x-ray, bore .030, line hone, deck and square a LQ4 block. Everything measured out great. I purchased a Wiesco/K1 408 setup. I had them file fit the rings and hone the block to Wiesco's specs for street strip boost. I asked for .021 top ring and .023 second ring. They assembled to short block. I installed new LS9 head gaskets with ARP studs. I installed Tick Performance LS2 stage 2 blower camshaft. I also put new LS7 lifters, cut to length Tick push-rods, trunion upgrades, BTR .660 springs and platinum retainers. I hand lapped the valves in and the machine shop decked the surface and checked vacuum on the valves. They said they are all in spec and would work fine until I put new heads on. I trust the machine shop, but things happen. I started the engine and let it get to temp and shut it off. Doing this a few times in the garage. I finally got the tune to idle and started to tune using EFI Live. I was very easy on the car for the last 300 miles. I made sure I deacceled alot to pull a vacuum on the rings. I feel I broke the engine in well. Nothing over 3500 for awhile. I let it get to full temp before harder pulls.
I ran a compression test and I get very weird numbers. I get 155 on most cylinders but 3 yielded 190. What is going on? I would guess the rings have seated by now right? 150 seems low but if they all read that I would be fine with it. I live at 5000 ft elevation so compression tests usually read lower than at sea level.
I ran a compression test and I get very weird numbers. I get 155 on most cylinders but 3 yielded 190. What is going on? I would guess the rings have seated by now right? 150 seems low but if they all read that I would be fine with it. I live at 5000 ft elevation so compression tests usually read lower than at sea level.
