Well, the ol' Procharger takes out another LT1....

This is a bone stock 50,000 mile LT1 with an 8LB Procharger. I cannot say for sure that a ring land is broke, but the engine is blowing lots of smoke out of both breathers in the valve covers. Even smokes out of these breathers at idle. In fact, we put it on the dyno a couple of days ago, and got lots of smoke pumping not only out of the breathers (breather is installed in both valve covers), but we also got lots of blue smoke out of the tail pipes too. A week ago, this motor was very tight. Seems like this problem started after a few WOT runs with the newly installed LT4 knock module.

I don't think it ever went lean. The Wideband showed the air / fuel ratio at a rich 11.7 all the way up to 5,900 rpm and 8 to 9 psi boost. Also, the MSD 6AL-BTM was set to retard timing 1 degree for every 1 psi of boost. There is no coolant in the oil.

Anyway, for my question:

I think it would be best to purchase a new 383 short block with forged 9.0 to 1 pistons and a set of good steel rods. What are my options? I looked through the Scoggin-Dickey catalog and did not see any LT1 shortblocks. Lots of BB and SB Chev engines, but no LT1s. My problem is that I don't trust any machine shops around here for a good shortblock.

It seems like the Prochargers, Vortechs, and the like have taken out a good many LT1s on this board, so I guess the various options to a new motor have been discussed here more than once before.

If I continue to run boost (really would like to increase boost to about 12 psi), I feel that there are 2 absolute requirements. These are:

1. Forged pistons that [WILL NOT] break (with proper fueling)
2. Compression of about 9.0 to 1

Aditionally, I think I would be wise to have a better connecting rod than the stockers.

And, I guess, last but not least; If I go with a new shortblock, I might as well go with a 383.

Please tell me what you think would be the best route to go at a reasonable price.

Thanks,
Ron

98 TA ... Heads, Cam, Headers car
95 TA ... Procharger
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Reasonable price? Sell the blower!

The above is half serious, at least. A 12psi 383 is an expensive proposition done right. It's a big subject, but a couple of comments. First, if you want to run 12psi on pump gas, the CR should be no more than 8.5:1. Someone tells you different, they are wrong. An adequate fuel system, as you have already indicated, is key. As far as pistons go, I recommend the JE "extreme duty" piston. It's heavy, but strong, and set up right the weight won't mean much 'cause you won't have to rev it high.

If you really want to do this cheap, just have your existing motor freshened up with a good set of pistons and keep running 8psi. Otherwise, get out that check book and and maybe talk to Bret Bauer (Bauer Racing Engines). He advertises on the board and really knows his stuff.

Rich Krause

 

The cheapest route would be to throw in some SPeed Pro Forged pistons. I believe that summit and jegs sell them in standard bore sizes (they are not listed in the catalog you have to call). I had my block bored .030 over, and the cost of the short block that route was around $1400 all said and done. Replacing just the pistons, gaskets and bearings shoud be around $500 or so less. But my idea is if your going to go thru the hassle of pulling the motor, do it right. I reused my stock crank and rods and it is living under 542 Rwhp, but i don't have a pulley and a tight belt side loading the crank either.

 

Thanks for the info

I was looking in the GP section and noticed that Bret Bauer (Bauer Racing Engines) has a GP on 383 short block sets.

Check it out:
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Stage 2 Dish Piston 383

Scat 4340 Forged Crankshaft
Howards 4340 Forged I Beam Rods
Ross Dish Pistons
Total Seal Classic Xtreme Rings
Clevite H Series Tri Metal Rod Bearings

$1910 + shipping
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This looks to be a good deal. Not really sure what all it includes, but may be very worthwhile.

Ron,

 

My builder had the exact same problem with his stock LT1. The ring lands were cracked on a few pistons. First recommendation is that if you intend to stay boosted reliably a standalone programmable ecu is an absolute MUST! He is in the process of building up a 383 w/ afr heads and a standalone. He learned his lesson using the btm.

 

Whats your goals, and why must you go for a 383 and not a 355? If the one purpose of your car is to race than sure 383. Given it cost about the same to build a 355. I think its stronger, and more reliable IMO. Forged rods, and pistons at the least. Take a look at my web page. My setup has lasted around 8k so far. Very streetable setup. No dyno numbers but its a 11second car all day long. My motor is suppose to be 8.5 to 1, but its more like 8 to 1. Budget and Super Charger in the same post LOL. It can be done but you need to do your own work.

 

It is not true that an aftermarket ECU is necessary to make a hi-po blown LT1 work. Just not so. Now that the Acceleronics low impedance injecor driver box is available, the limits have been pushed even further. And if ever tried to completely dial-in an aftermarket ECU, you wouldn't be so sanguine about recommending that route. If you need it, you need it. But if you don't, stay away.

Rich Krause

 

LJ's box is supposed to working very well for those who are using it... When it's time for my engine to be rebuilt I will be going 383 8.5:1 forged everything and 4 bolts mains... I want it done and done right the first time. If you skimp it will always come back to bite you in the ***. Good luck.

 

I am not saying that it's a must for a hi-po but having complete control of timing curve and fuel is going to be much more reliable. Not to mention that speedpro for example come integrated with a wide band 02 that you can run in closed loop under wot. As for dialing in the ecu.. if you were to go to a reputable tuner more than likely he/she will already have a basemap that closely resembles you setup and go from there. Unlike my car, there are hundreds of lt1's running an aftermarket ecu. As for the harness, unlike myself, you guys are lucky as there is a "plug and play" available. I realize that if you choose to do it yourself it can be a pain in the ***, but in the world of the internet you can usually find someone willing to part with a basemap that will get you driving around or that has a good drivability map. But as for me..I didn't have that option.. yet my car was completely drivable and boostin within 2 hours of tunning by an experienced tunner. It just takes blowing one motor to warrant the cost of an ecu. My friend has about 20G in his complete 383 procharged motor and that is the way he feels too. Granted he is looking to push 900 hp.. I don't know that I would want to find the limits of the Acceleronics the hard way. I say do it right the first time. But heck I don't know crap I drive a honda

 

>I went through http://www.cmotorsports.com/ who is also a sponsor (not to take away from the current GP going on) , and you could get a price from both , and make your money go a long(er) way .
I just have to say watch out for some of the mail-order vendors (by keeping an eye on the length of time) 60-90 days after they charge your card you should have your parts in hand no exceptions . After that it takes an arm and leg to resolve ... that's personal experiance .
good luck !