LT1 Rebuild/Refresh
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From: Pennsylvania
LT1 Rebuild/Refresh Ok guys,
Most people on here seem very knowledgeable. I am sure this question has been asked before but, I am looking to rebuild/ refresh my engine. 150xxx plus miles on it. I want to give this car a new life. So with basically stock engine what am i better off keeping for the rebuild and what am i better off buying new? Engine has no real issues, small oil leak but i am thinking it is the water pump seal and opti seal. I want to put a cam in it. Car will not see the strip. I want a good strong motor for show and street-ability. Give me your inputs.
Thanks in advance
Chris
Most people on here seem very knowledgeable. I am sure this question has been asked before but, I am looking to rebuild/ refresh my engine. 150xxx plus miles on it. I want to give this car a new life. So with basically stock engine what am i better off keeping for the rebuild and what am i better off buying new? Engine has no real issues, small oil leak but i am thinking it is the water pump seal and opti seal. I want to put a cam in it. Car will not see the strip. I want a good strong motor for show and street-ability. Give me your inputs.
Thanks in advance
Chris
SBC crate motors are cheap and plentiful. Good assemblies are just about falling out of trees. Rebuilding vs. replacing is mostly a cost issue for most folks, but there's also the time consideration.
If you do it yourself you have to buy all the parts, strip it down, get everything off to the machine shop, pick it up, assemble, etc, etc, etc. And that's assuming everything's OK. Sometimes it runs into more money if the block is cracked, the crank is bent, etc. If everything goes well, you can get it done in a month. But things usually don't go well, so figure 2 months.
Or, you can call any one of a dozen companies and order an over the counter crate motor. You can even get a good one directly from your local GM dealership. If you want something special, contact Mike Forte at Forte's Parts to build you exactly what you want.
Cost wise, it's generally cheaper to buy an off the shelf crate motor than it is to rebuild what you have. Even including sales tax and shipping to your door step.
Time wise, you can probably do the swap in a week end if you're lucky. But I would plan 4 full days. I R&R'ed a SBC from GMC Jimmy in one day, and tuned and broke it in the next day. But I'm not usually that lucky.
If you do it yourself you have to buy all the parts, strip it down, get everything off to the machine shop, pick it up, assemble, etc, etc, etc. And that's assuming everything's OK. Sometimes it runs into more money if the block is cracked, the crank is bent, etc. If everything goes well, you can get it done in a month. But things usually don't go well, so figure 2 months.
Or, you can call any one of a dozen companies and order an over the counter crate motor. You can even get a good one directly from your local GM dealership. If you want something special, contact Mike Forte at Forte's Parts to build you exactly what you want.
Cost wise, it's generally cheaper to buy an off the shelf crate motor than it is to rebuild what you have. Even including sales tax and shipping to your door step.
Time wise, you can probably do the swap in a week end if you're lucky. But I would plan 4 full days. I R&R'ed a SBC from GMC Jimmy in one day, and tuned and broke it in the next day. But I'm not usually that lucky.
A cheap rebuild of a modern engine is often a step backwards. If you want to refresh what you have on a budget the only things I would look at replacing are rod bolts with a hone on the big ends and the bearings and rings, you will have more into that than you think. If you want to do pistons then get a 6.0" Scat rod and something like a Mahle PowerPak piston or equivalent light weight 4032 thin ring pack piston, not the $100 set the machineshop recommends.
Stock stuff is pretty good and cheap aftermarket pistons are heavier with thicker more parasitic ring package that wears the bore more.
I I had an OLD carbed SBC vehicle I would look at the cheap crate engine option, with an LT1 though the selection is much smaller and the biggest LT1 performance engine builder has been documented to be not so good despite what the magazines will tell you, and most of his customers for the first 6 months or a year till the stuff fails after not making the power a stock shortblock would have.
Stock stuff is pretty good and cheap aftermarket pistons are heavier with thicker more parasitic ring package that wears the bore more.
I I had an OLD carbed SBC vehicle I would look at the cheap crate engine option, with an LT1 though the selection is much smaller and the biggest LT1 performance engine builder has been documented to be not so good despite what the magazines will tell you, and most of his customers for the first 6 months or a year till the stuff fails after not making the power a stock shortblock would have.
.... and the biggest LT1 performance engine builder has been documented to be not so good despite what the magazines will tell you, and most of his customers for the first 6 months or a year till the stuff fails after not making the power a stock shortblock would have.
That comment wasn't to say there are no good shops, just to say that the previous poster's ideas about simply picking up the phone and calling any of a bunch of builders that would have one on a shelf was not really all that good an idea.
IMO a LOT of guys do "performance builds" when they could have gotten a lot more bang for the buck with a good refresh. Guys get hung up on getting rid of stock parts and then compromise the topend budget where power is really made.
Look what vtec and bowtienut are doing on refreshed stock shortblocks both cars have stock shortblocks with ported GM LT1 heads but are faster than most strokers even with aftermarket heads.
IMO a LOT of guys do "performance builds" when they could have gotten a lot more bang for the buck with a good refresh. Guys get hung up on getting rid of stock parts and then compromise the topend budget where power is really made.
Look what vtec and bowtienut are doing on refreshed stock shortblocks both cars have stock shortblocks with ported GM LT1 heads but are faster than most strokers even with aftermarket heads.
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From: Pennsylvania
Ok thanks guys. But my issue is not whether I should buy a crate engine. I will be keeping my block. I guess my original question should have read: if all internal major parts are ok. Am I better off keeping the stock crank rather than an aftermarket?? I want to know in a perfect world, what is better to keep stock and what the problem children are in these engines??
I would put the stock crank up against the chinese forged stuff all day long, not aware of a single case of anyone overpowering the stock crank. The Eagle cast cranks on the otherhand are so weak that halfased strokers making less power than good stock shorblock builds shatter the cast Eagle crank.
If a shop suggests you do anything more than polish and maybe rebalance a undamaged stock crank walk away and don't trust them with an oilchange. If they suggest an aftermarket cast crank, walk away, the Scat seems to be OK when the stock one is bulletproof why swap it.
If a shop suggests you do anything more than polish and maybe rebalance a undamaged stock crank walk away and don't trust them with an oilchange. If they suggest an aftermarket cast crank, walk away, the Scat seems to be OK when the stock one is bulletproof why swap it.
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If it's not burning oil or coolant then leave it alone. If you want to know how your cylinders are holding pressure then get a leak down. If you take great care in installing a cam by making sure not to dump engine gunk into the oil pan while the timing cover is off, or into the heads while changing springs then the engine will last many more miles.
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150k mi motor is getting closer to old than not so if it were my motor and wanted to do a cam swap I would just do a crank polish, have the stock rods resized and fitted with ARP fasteners and get the blocked honed with a new ring pac as capricemgr notes. if going 355 because block needs a bore get quality pistons, not cheap heavy slugs. New bearings all around and you are good to go for a cam install and send your heads out to Lloyd Elliott or AI. Either of those can also spec a cam matched for your needs.
if you are able to pull the motor yourself and send the short block to a quality machine shop to do the refresh fine or you can dissesamble it and send the parts/block in and assemble yourself. FWIW I chose to have the short block done and I put the rest of the motor togeather
if you are able to pull the motor yourself and send the short block to a quality machine shop to do the refresh fine or you can dissesamble it and send the parts/block in and assemble yourself. FWIW I chose to have the short block done and I put the rest of the motor togeather
Thread Starter
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From: Pennsylvania
Thank you everyone.
Keep it coming, This is the information is was looking for!!
I think i will definitely keep the stock crank and just polish.
Gonna disassemble myself and send it out to have it looked over and new bearings and rods. What is a good set of pistons that are close to stock weight?
Can someone give me a good parts list for my plans?
*Pistons
*Rods
*Bearings
*Cam for a mild driving with some A** behind it.
Thnks in advance
Chris
Keep it coming, This is the information is was looking for!!
I think i will definitely keep the stock crank and just polish.
Gonna disassemble myself and send it out to have it looked over and new bearings and rods. What is a good set of pistons that are close to stock weight?
Can someone give me a good parts list for my plans?
*Pistons
*Rods
*Bearings
*Cam for a mild driving with some A** behind it.
Thnks in advance
Chris
If you are hell bent on doing this you can actually reuse the entire stock rotating assembly including pistons if the cylinders are measured and are only in need of a hone. It'll save a bunch of money as well, and if staying N/A, will last you at least another 150K.
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bubee
before you buy any pistons have your block cleaned, measured by a machine shop first. if you have a running motor you most likely only need a new set of rings for your stock pistons as the block may only need a hone. Just get your rods resized with arp fasteners. Clevite bearings.
you will get a wide range of opinions on a off the shelf cam. if you are not having heads ported than LE 211/219, Crane 227, Comp 502, Comp XFI 466 all work decent with stock heads. A custom grind typically yields more performance results IF you are doing ported heads
first think big picture on what your finished build results are and get the right work done and parts for that goal.
If just doing a engine refresh with bearings & rings and stock heads, stay on the small side for cam but absolutely get new valve springs which will be noted on your cam card.
you will need a pcm tune for the new cam
before you buy any pistons have your block cleaned, measured by a machine shop first. if you have a running motor you most likely only need a new set of rings for your stock pistons as the block may only need a hone. Just get your rods resized with arp fasteners. Clevite bearings.
you will get a wide range of opinions on a off the shelf cam. if you are not having heads ported than LE 211/219, Crane 227, Comp 502, Comp XFI 466 all work decent with stock heads. A custom grind typically yields more performance results IF you are doing ported heads
first think big picture on what your finished build results are and get the right work done and parts for that goal.
If just doing a engine refresh with bearings & rings and stock heads, stay on the small side for cam but absolutely get new valve springs which will be noted on your cam card.
you will need a pcm tune for the new cam
Never buy cheap parts, they're too expensive.
The crank will probably need to be cut, polished, and balanced. The rods will need to be resized. And you'll probably need new pistons. Talk to the machine shop and see what all that will cost. You'll probably find it's cheaper to buy a new rotating assembly.
Stock and GMPP are actually pretty good stuff. They lasted 150K miles in your car, what more can you ask for?
Unless you're racing on a regular basis. Then a lot of the small stuff should be replaced with tougher stuff.
Thank you everyone.
Keep it coming, This is the information is was looking for!!
I think i will definitely keep the stock crank and just polish.
Gonna disassemble myself and send it out to have it looked over and new bearings and rods. What is a good set of pistons that are close to stock weight?
Can someone give me a good parts list for my plans?
*Pistons
*Rods
*Bearings
*Cam for a mild driving with some A** behind it.
Thnks in advance
Chris
Keep it coming, This is the information is was looking for!!
I think i will definitely keep the stock crank and just polish.
Gonna disassemble myself and send it out to have it looked over and new bearings and rods. What is a good set of pistons that are close to stock weight?
Can someone give me a good parts list for my plans?
*Pistons
*Rods
*Bearings
*Cam for a mild driving with some A** behind it.
Thnks in advance
Chris
A good set of stock replacement rods from GM will easily last another 100K miles of hard use.
I always use Clevite bearings.
Buy this kind of stuff as a kit. You'll get everything you need, and all the parts will match. Usually a little bit cheaper than buying them one at a time, too.
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From: Raleigh, NC
If it's healthy and makes good oil pressure, there's no reason to rebuild it. The oil pressure should be fairly obvious, a leakdown test will tell you what sort of shape the cylinders are in. I'd just do a cam swap and fix all of the oil leaks while you're in there. Take your time and exercise care in doing the work (don't nick the bearings sliding the cam in or let trash/gunk contaminate anything) and it will be fine. Make sure to do quality springs and a set of non-self aligning 1.6 rockers with guideplates. The stock lifters can be re-used.
If you've run synthetic oil and changed it regularly for most or all of the car's life then the inside of the motor is likely in pretty good shape. I've seen many LT motors with well over 100k opened up and if they've had good oil they usually look almost new inside.
If it's necessary to rebuild, then stick with the stock crank and rods and add a set of ARP bolts and Clevite bearings. If the stock pistons can be re-used they're good too, just re-ring them and get a hone. If not then make sure you buy a quality lightweight replacement, as mentioned.
Oh, one other thing. If you decide to mess with the heads, make sure you send them to one of the 2 or 3 reputable porters people will mention on here. People (amateurs and pros alike) often ruin LT1 heads when they try to go about doing a port or "clean up" job on them and don't know what they're doing. Don't let your local machine shop try to tell you how these heads "should be done", 95% of them will be applying old-school SBC porting techniques that do not work well with these heads. Go with a KNOWN quantity in the LT world who has garnered documented results.
If you've run synthetic oil and changed it regularly for most or all of the car's life then the inside of the motor is likely in pretty good shape. I've seen many LT motors with well over 100k opened up and if they've had good oil they usually look almost new inside.
If it's necessary to rebuild, then stick with the stock crank and rods and add a set of ARP bolts and Clevite bearings. If the stock pistons can be re-used they're good too, just re-ring them and get a hone. If not then make sure you buy a quality lightweight replacement, as mentioned.
Oh, one other thing. If you decide to mess with the heads, make sure you send them to one of the 2 or 3 reputable porters people will mention on here. People (amateurs and pros alike) often ruin LT1 heads when they try to go about doing a port or "clean up" job on them and don't know what they're doing. Don't let your local machine shop try to tell you how these heads "should be done", 95% of them will be applying old-school SBC porting techniques that do not work well with these heads. Go with a KNOWN quantity in the LT world who has garnered documented results.
To give you an idea I just picked up my short block from a machine shop local in Tampa and it cost 1400 bucks to have my 100k short block refreshed. Everything checked & cleaned, new rings, We reused the stock rods, pistons, & crank, new bearings & felpro gasket set.
.boB I suspect your experience is with older engines, the LT1 with it's much cleaner injection than earlier motors and thin rings on light pistons generally will NOT need a bore or crank cut at 150K miles. The injection keeps the oil cleaner and the rings put less wear on the bore.
I have leak down tested a 227K mile LT1 at under 5% leakdown and 185-190psi cranking compression from a 10:1 iron head LT1.
I have leak down tested a 227K mile LT1 at under 5% leakdown and 185-190psi cranking compression from a 10:1 iron head LT1.
I'm in the same boat I just brought a 97 SS with 133xxx on it and I have a shortblock from another car that had started showing low oil pressure so I stopped driving it and built an all forged 383 to replace it. Anyway I have been contemplating buying a set of Scat Pro Comp 6" 4340 forged rods with 7/16 capscrews and some forged Probe SRS or SRP pistons with all new rings and bearings along with a cam and my LE3 heads then putting it in my SS. But price what it cost to resize the rods and add the ARP bolts vs buying the Scat rods which cost about $350 then as mentioned buy lw forged pistons and keep the stock crank unless it's FUBRed then have the rotating assembly balanced.
Mine ate the camshaft and I tore it apart to clean out the shrapnel. I replaced the bearings, rings and a few lifters. My block was worn but not enough to worry about. Took care of the ridge at the top of the cylinders, cleaned up the cylinders with a ball hone, put it back together. The only hitch was on my block I had to buy three sets of main bearings to get the fit right. 001 under, .001 over and standard. Needed the .001 under set just for the rear main, couldn't find just the rear main bearing so I bought another complete set. I looked into a HP crate engine but couldn't find anything that sounded right for what I wanted. My big error was picking the wrong shop to freshen the heads. Found the master head rebuilder in this area. Has a Serdi seat machine with laser spoting and yada yada yada. He did the heads and I picked them up. I could see light through the ports so I took them back and he did them again. Still could see light, so he did them again. By that time the valves were sunk in the heads and I just gave up and put them on. They are junk and I need to come up with a different set.
Al
Al