metalmonkey47 Posted February 14, 2014 Author Report Share Posted February 14, 2014 Just out of curiosity, what was the percentage of leak down you had? 20% is what the tester read, but it sounded like a LOT more. yeah, what happened with that leakdown test? and im just gonna say it right now... KA24 swap when the L takes a dump. SRs are for rich kids... lol SR would be a good cheapie. Black top is VVT too. I'd get it for less then what I spent on the LZ honestly. Hey, can't see the keyway with the timing cover. Don't remember myself, but if I spin the motor over can I see it from beneath? I don't recall off the top of my head how it looks down there. EDIT: Nevermind, forgot I had a video. Gonna need to pull the front cover. Quote Link to comment
Farmer Joe Posted February 14, 2014 Report Share Posted February 14, 2014 yeah, youll have to pull the cover... i guess im just biased with having the KA already.. it was so easy.. bolted in like another L-series with Redeyes mounts. Quote Link to comment
smoke Posted February 14, 2014 Report Share Posted February 14, 2014 20% is what the tester read, but it sounded like a LOT more. SR would be a good cheapie. Black top is VVT too. I'd get it for less then what I spent on the LZ honestly. Hey, can't see the keyway with the timing cover. Don't remember myself, but if I spin the motor over can I see it from beneath? I don't recall off the top of my head how it looks down there. EDIT: Nevermind, forgot I had a video. Gonna need to pull the front cover. Well, yeah, 20% is quite a bit, even if the engine was cold. Opinions vary on an acceptable percent. For some guys, anything near 10% and they will yank it apart. Contrary to what many believe, a race engine (many of them) will have an astonishing amount of blowby and still run super strong. In example, my Jeep runs 100 yards in 2.95 to 2.97 seconds at over 100 mph, IN THE SAND. Its leak down at this point is way past what a guy with a street driven engine would want to rebuild it at. But, at 9000 rpm and a bunch of boost, I am actually running a little faster than I was when it was new and had 3%. I say flog it for a while and check it again when hot, I bet it comes up. Quote Link to comment
metalmonkey47 Posted February 14, 2014 Author Report Share Posted February 14, 2014 Anyone have thrust specs on the crank? It's got a good bit of walk front to back (didn't see it for myself, but my buddy working on it mentioned he noticed it when we was inspecting the crank snout.) I'm gonna drop my mig welder off in the shop tomorrow and we're gonna weld up the crank, and grind it straight. Should be finished up by tomorrow. Well, yeah, 20% is quite a bit, even if the engine was cold. Opinions vary on an acceptable percent. For some guys, anything near 10% and they will yank it apart. Contrary to what many believe, a race engine (many of them) will have an astonishing amount of blowby and still run super strong. In example, my Jeep runs 100 yards in 2.95 to 2.97 seconds at over 100 mph, IN THE SAND. Its leak down at this point is way past what a guy with a street driven engine would want to rebuild it at. But, at 9000 rpm and a bunch of boost, I am actually running a little faster than I was when it was new and had 3%. I say flog it for a while and check it again when hot, I bet it comes up. Hmmm well put. I'm gonna beat it up for a little bit and see how it goes. I'll update my build thread and see how it goes in a few thousand more miles. The motor ran strong, so I don't see any reason why I'd need to tear it apart just yet. I figured if it was already most of the way apart, why not. But I don't think that will be an issue. yeah, youll have to pull the cover... i guess im just biased with having the KA already.. it was so easy.. bolted in like another L-series with Redeyes mounts. Well, we have them availible (the sr) at a good price, and the swap doesn't seem difficlt. I've been reading and researching for months and the hardest part is turbo plumbing, oil lines, etc. Bolts in for the most part, just have to cut the motor mounts on the frame free, and weld them back an inch or so. Quote Link to comment
smoke Posted February 14, 2014 Report Share Posted February 14, 2014 I think the end play should be around 4 to 7 tho. Funny, end play was what I thought your noise was at first. Quote Link to comment
Driftease Posted February 17, 2014 Report Share Posted February 17, 2014 Do I get any credit for the knocking sound lol. As far as leakdown who built your motor, were the pistons and rings sized properly for the application. Like smoke said purpose built race engines have relatively high ring leakage when cold due to the large ring gap required for very high demand engines (turbo, nitrous, high compression ect). If yours was not built for any of the above I would ask is the bore tapered glazed scored or just plain out of spec, was it ever measured at all (not trying to be condescending I'v been there) Quote Link to comment
datzenmike Posted February 17, 2014 Report Share Posted February 17, 2014 20% is what the tester read, but it sounded like a LOT more. . Was the sound at the exhaust (tail pipe) or the intake (carb) as this would mean the leak is a valve not necessarily the rings. 1 Quote Link to comment
smoke Posted February 17, 2014 Report Share Posted February 17, 2014 That is a really good question. It's too bad you are not closer, we could hook it up to mine and see where it's hissing. Quote Link to comment
metalmonkey47 Posted February 20, 2014 Author Report Share Posted February 20, 2014 Do I get any credit for the knocking sound lol. As far as leakdown who built your motor, were the pistons and rings sized properly for the application. Like smoke said purpose built race engines have relatively high ring leakage when cold due to the large ring gap required for very high demand engines (turbo, nitrous, high compression ect). If yours was not built for any of the above I would ask is the bore tapered glazed scored or just plain out of spec, was it ever measured at all (not trying to be condescending I'v been there) The motor was built by a buddy, but not for stock specs. It was built to run a shit ton of boost, hence the BBC rod bolts, ARP head & main studs, etc. It's also got forged mahle pistons (something Mitsubishi) with fully floating wrist pins, and moly rings. Maybe the leak down is normal for this motor, I suppose it's something I can live with. I just hate thinking I'm running lower the normal compression. as of right now, i still don't even have the truck back. Kind of nerve racking. Was the sound at the exhaust (tail pipe) or the intake (carb) as this would mean the leak is a valve not necessarily the rings. CYL 1 had a slight leak at the intake valve fully shut, but ever so slight... (hissing in the intake) The heads gonna come off when I get another DD and I'm gonna gut the head and lap the valves. Quote Link to comment
smoke Posted February 20, 2014 Report Share Posted February 20, 2014 If it was set up to run a bunch of boost originally, then yeah, your compression will be a little low (or at least should be). But, I get what you're saying, all that it should have. Quote Link to comment
Driftease Posted February 20, 2014 Report Share Posted February 20, 2014 I use a big ring gap for turbo that seals up more as the engine heats up otherwise you will have nice broken ring lands when they get hot under boost. If you plan on running a turbo then you need to be aware of your valve face margin (the valves contact area to the seat) I like to run .5 mm on intake and .75 on exhaust on my ka e the extra on the ex is for heat disapation and helps reduce detonation. 1 Quote Link to comment
smoke Posted February 20, 2014 Report Share Posted February 20, 2014 And make sure your spare has 31.7 pounds in it. Quote Link to comment
datzenmike Posted February 20, 2014 Report Share Posted February 20, 2014 Need more info on the pistons. Were they forged? Forged will run way more piston to wall clearance than hyper-eutectic ones. The aluminum expands from the heat and clearances close up. If your motor was good and hot when the compression was done then disregard this. Quote Link to comment
Laecaon Posted February 21, 2014 Report Share Posted February 21, 2014 mahle forged pistons for the Mitsu 4G63 motor... Quote Link to comment
metalmonkey47 Posted February 21, 2014 Author Report Share Posted February 21, 2014 Awesome guys! SO my compression may be right on point then, I suppose I'll need to re-test it once I've got it running, up to temp again. Thanks Jacob, those are the ones. I figured it was 4G63 but I wasn't 100%. Didn't want to say for sure until I found my info I had written down. It's these pistons to be exact: http://www.horsepowerfreaks.com/partdetails/Mahle/engine/pistons/PowerPak_Mitsubishi_4G63_89-92/7127 Quote Link to comment
Laecaon Posted February 21, 2014 Report Share Posted February 21, 2014 Yea, I was looking at running 4g63 pistons in my L18, with long rods. Quote Link to comment
smoke Posted February 21, 2014 Report Share Posted February 21, 2014 Yeah, you're probably just fine and, sometimes when I am doing a leakdown and hear a little hissing from the intake or exhaust, I can just tap the valve spring of the offending cylinder with a rubber mallet and have it stop. Quote Link to comment
Driftease Posted February 21, 2014 Report Share Posted February 21, 2014 true^^^^^ old carbon and shit will get caught and hold it open a hair Quote Link to comment
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