Z-TARD Posted May 1, 2004 Share Posted May 1, 2004 Just picked up an LT1 out of a 93 Z28 today. One of those "Target of opportunity" purchases, more to keep someone else from getting it rather than out of actual need. Total price was $141.58, so I HAD to grab it. It's a short block, and looks to be a fairly recent rebuild as the cross hatch pattern from the cylinder hone can still be seen in the cylinders. There is no ridge at the top of the cylinder either, and strangely they measure out at exactly 4" across the bore, like a brand new engine almost. The front passenger side cylinder has some light surface rust, perhaps from a blown head gasket. The engine turns over by hand with little resistance, and no clunkity-clunk noises from broken hardware. Hopefully all I will have to do is clean up the one cylinder with a light hone, maybe re-ring the pistons and I should be able to run the engine. Not being too familiar with LT1's, I have a few questions to ask you guys (Yes, I used the search function, try typing in LT1 and see how many pages of info come up, it's in the billions): 1) Will my aftermarket aluminum heads, purchased for a pre 1987 block, work on the LT1? 2) I know that it has a provision for a front mounted distribution system, but will I be able to use a standard rear mount distributor on it instead? It appears that the distributor drive gear is still there, but driving only the oil pump on the LT1. 3)Does anyone manufacture a front mount, HEI type distributor for the LT1, so it can be run without the ECU? 4) will a cam designed to retro fit roller rockers into a pre 1987 block work in the LT1? I'm sure I will have more questions as I progress on this project. For the time being I have put my pre 87, 383 stroker motor on hold, as I may be able to use this motor to get on the road much more quickly, and without the pain of trying to adapt an older engine to the T-56 tranny. Thanks in advance for the help, Mike Quote Link to comment Share on other sites More sharing options...
Tim240z Posted May 1, 2004 Share Posted May 1, 2004 No, LT1 type heads will need to be used. You can convert the LT1 intake to run a rear mount dizzy... If you are planning to build it with older type parts, you will be better off starting with an older block...... There is nothing special about the LT1 block... Tim Quote Link to comment Share on other sites More sharing options...
Z-TARD Posted May 2, 2004 Author Share Posted May 2, 2004 Ooops. I never thought to count the water holes on this thing before purchase. What does Chevy think they are doing by re-inventing the wheel (or reverse flow cylinder head) like this! Looks like I'll be shopping for some LT1 heads on Ebay, along with the timing cover, intake manifold, water pump, and all the other stuff that doesnt interchange. I wonder what would happen if you tried to block the reverse flow passages on the block to make it run like a normal SBC cooling system (Not totally block, but divert into the block instead of the cylinder heads) Probably more trouble than its worth, and I suppose I could use the benefit of cooler cylinder heads for running higher compression too. Mike Quote Link to comment Share on other sites More sharing options...
CableSrv Posted May 2, 2004 Share Posted May 2, 2004 ztard if your looking for performance there is a shop that can reengineer old sbc style heads to work with the lt1's reverse cooling I've only heard of them doing it on canfield heads tho... which stock with 225cc runners they flow at like 302cfm at .600 lift stock castings goto http://www.lt1tech.com and you can find some info on that. in fact here is the exact post for ya http://lt1tech.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=6;t=001763 he list the shop's name and person and number to call to get it done. He also stated it was like 1900 for the conversion with heads.... not sure if they are full heads or just bare tho.. Quote Link to comment Share on other sites More sharing options...
Z-TARD Posted May 3, 2004 Author Share Posted May 3, 2004 Very cool. If it works with the Canfields, it would probably work on my Topline 220's as well. There is a small hole on these heads where the extra coolant passage is on the LT1 block, I think this hole could be enlarged enough to provide sufficient coolant flow. The only problem I see is that it is ver close to the oil drain hole at either end of the cylinder head, the corrosponding area of the LT1 block might be too built up for the coolant passage to allow oil to drain into the lifter valley through these holes. I'll have to take a closer look at that. Thanks for the link, the gears in my head are turing again Mike Quote Link to comment Share on other sites More sharing options...
Z-TARD Posted May 3, 2004 Author Share Posted May 3, 2004 Ok, after another look, it appears that this is very doable. It will require the enlargement of the coolant passage holes on either end of the head, along with milling a channel for the oil drain hole to rout it to the lifter valley. Maybe some mild grinding on the block near the front coolant passage to aid oil drainback as well. I'm sure someone will tell me why this can't be done, but I'm just retarded enough that it would be like adding fuel to the fire Mike Quote Link to comment Share on other sites More sharing options...
CableSrv Posted May 3, 2004 Share Posted May 3, 2004 from what I gather from the post was they welded alot of it closed and remachined the correct openings and port matched them to the lt1 block. not sure about just enlarging tho as that might be bad especially for you gasket. Quote Link to comment Share on other sites More sharing options...
Z-TARD Posted May 3, 2004 Author Share Posted May 3, 2004 I just re read it again, don't want to go buck wild on my $1000 heads with a dremel until I'm sure . None of the posts said anything about welding at all, although if welding is involved I can do that too. Aluminum isn't hard if you have a good TIG machine. I only read references about the guy named Walden programing his CNC mill to convert the heads to LT1 reverse flow. I've spent the last hour or so with all my lights turned off, shining a flashlight inside my Topline heads so I can get a better idea of exactly how much room is available in the coolant passage at either end of the head. There IS enough room to make a decent sized opening there, although I wont start cutting on them until I have a gasket to index from. Don't want to shoot all the coolant into the oil pan and have Yoo-Hoo come jetting out of my valve covers . The oil drain passage will have to be re-routed either diagonally so it dumps directly onto the lifters of the end cylinders, or straight inwards into the lifter vally, with a corrosponding passage ground into the block directly above the main coolant port that feeds into the head. A CNC mill isn't required for this kind of work at all, they probably use that just for the sake of making all their heads look uniform. A dremel should be sufficient for enlarging the coolant passages, as long as I take care not to let it jitter around and scratch up the deck surface. A pnuematic grinder with a rotary file will work for the block, while I'm at it I'll enlarge and smooth out the oil drainback holes in the lifter vally as well. I'm going to have the block hot tanked and honed, and put in new cam, rod, and main bearings, add a set of new rings and it should be ready to run. Anyone know of a timing chain cover that doesnt have the hole for the optispark in it? thanks again for the link CableSrv. Mike Quote Link to comment Share on other sites More sharing options...
Z-TARD Posted May 4, 2004 Author Share Posted May 4, 2004 Too bad there's no emoticon of a guy ingesting his own foot After several more test fittings and inspections, I noticed that the reverse flow coolant port overlaps the oil drain hole on the head by a fair margin. Welding and machining would be required after all I have the capability to perform these oporations, but I'm not 100% sure I could pull it off without destroying my cylinder heads. I dont really feel like munching my quadrillion dollar heads for use on a $140 junkyard block. Better to just get a pair of LT1 heads off ebay for $300. I'll probably save the LT1 for some later project, maybe something force fed Mike Quote Link to comment Share on other sites More sharing options...
Tim240z Posted May 4, 2004 Share Posted May 4, 2004 Or sell it to me!! Quote Link to comment Share on other sites More sharing options...
80LS1T Posted May 4, 2004 Share Posted May 4, 2004 Tim, what are you up to now? Guy Quote Link to comment Share on other sites More sharing options...
Tim240z Posted May 4, 2004 Share Posted May 4, 2004 Tim' date=' what are you up to now? Guy[/quote'] All kinds of wierd stuff!! Quote Link to comment Share on other sites More sharing options...
CableSrv Posted May 4, 2004 Share Posted May 4, 2004 tim you already got a lt1.... what do you plan to do ? twin lt1's ? one for rear and one for front ? "thinks about that concept for a second.... MY GOD THAT WOULD RULE!!" awd twin turbo twin lt1!!! 240Z!!!! :rockon: :rockon: Quote Link to comment Share on other sites More sharing options...
Z-TARD Posted May 4, 2004 Author Share Posted May 4, 2004 I know, you're going to run it as a conjoined twin with your other LT1, making either a V16 or a W16 I guess I don't really need it now. I accomplished my mission of rescueing it from the junkyard, where it surely would have found it's way into a less worthy donor vehicle than a Z. Email or PM me if you wanna work out a deal for it. Mike Quote Link to comment Share on other sites More sharing options...
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