D.O.A engine ... 350 tbi motor fixup/buildup

[sweetk30]

found all the info needed on lt1 swap to tbi motor on thirdgen

link : http://www.thirdgen.org/techboard/tbi/262466-lt1-cam-digest-ultimate.html

looks like we are good to go. even stock tbi springs will work.

talked to scott ( 4x4high ) and we just need to figure out the springs in the am to see if newer z28 springs for roller use or old school z28 flat tap springs.

 

[bigblock72]

The only possible snafu you may run into is the camshaft retainer. Some of the TBI blocks weren't tapped for the bolts for the retainer. Not a huge deal to drill and tap if necessary, just make sure you install the retainer before you bolt on the cam gear. Looks like your timing chain kit comes with everything you need (including the camshaft retainer and bolts) and should work fine.

Your valvesprings should be fine for the low engine speed you'll see. TBI heads are done by 4500 or so which doesn't put much stress on springs, just make sure they're set up properly to get the seat pressure you need otherwise you will run into valve float issues. With that being said better valve springs are cheap insurance in case of an accidental over-rev and just general long term reliability as Scott pointed out.

Make sure your rocker arm geometry is in the ball park, sometimes mixing and matching valvetrain parts can cause problems. Seems like every engine I build is a little different and I end up having custom pushrods made to make the rockers happy.

 

[4X4HIGH]

I've already talked with him and found out that the only thing that needs to be done is the dowel pin needs to be cut shorter to use that cam.

I was correct though, that cam drives the water pump on the LT1 engine so the timing set (cam gear to be exact) is different.

 

[bigblock72]

Yes the timing set is different between an LT1 (part# 12370835) and a regular GEN 1 small block (part# 12371043).

According to the GM Performance catalog the dowel needs to be pushed in to .300" from the LT1 dimension of .620". Sounds like you can just take a small hammer and gently tap the dowel to the correct dimension. I've never done this personally so take it for what it's worth.

 

[sweetk30]

update on the valve springs. called the place and thay said safe for the newer z28 roller cam use.

big reason for checking was scott (4x4high) said if old style z28 springs thay would be wrong pressures and break / wear out to fast from the faster working roller cam movement.

so now all is figured out the motor will start going together. keep checking back for more info.

 

[BGKYK5]

keep checking back for more info.

Yessir, gladly.

 

[sweetk30]

got the motor together few weeks ago. no major problems at all. parts whent in like a glove fit. i also installed new valve seals when swaping the springs.

today cleaned up the outside of the motor and taped it off and sprayed semi gloss black paint on it. then bolted up my extra serp belt setup so its less i have to swap from the other motor for reinstall.

will get pics sunday and post up. pics up now !!!

 

[sweetk30]

more pics

 

[sweetk30]

custom modifyed stock throttle bracket to work on carb intake and give me 100% full throttle.

 

[BGKYK5]

Where'd you get the TBI adapter?

 

[sweetk30]

Where'd you get the TBI adapter?

ebay.

and it can be used for front mount or back. and can also run tbi unit backwards.

and thanks eagle mark. i did make sure it was sealed with good gaskets and any un used holes were pluged good.

 

[eagle mark]

Quote:
Originally Posted by BGKYK5
Where'd you get the TBI adapter?

ebay.

When you install in permanently use sealer on both sides of gasket and make it permanent. These are notorious for vacuum leaks.

 

[4X4HIGH]

Quote:
Originally Posted by BGKYK5
Where'd you get the TBI adapter?

ebay.

When you install in permanently use sealer on both sides of gasket and make it permanent. These are notorious for vacuum leaks.

Unless you know someone who makes them on a CNC.

 

[scouthead]

Lookin good. When's it gonna fire?


Those headers going on a truck with an automatic? My cheapo Pacesetters look identical to those, but don't think they will clear my slave on the sm465...

 

[sweetk30]

well back from the DEEP dead pile just over 10.5 years of storage

friend was looking for a good short block and i still have this so i stripped all the good stuff and checked the #1 main and rod bearings and thats were stuff went down hill fast . i never heard this run and told was driving plow truck in the vehicle it was pulled from . i noticed it was a reman engine from the reman tags well it must of been neglected bad a bit as the copper was showing on the bearings bottom halfs .

so i guess if someone wants a .040 over 350 block to start with then there good to go . but she needs more work than he was going to want to put in to it . so long story short dont trust anything unless you know its history and hear it run . only thing i am out is time and few gaskets . as i got the motor in a swap for few hr's labor time deal .

i think some parts will now make there way in to a i know good running 350 or the roller rockers swap on to my new L31 vortec in the budget beater build not sure yet .

 

[1-ton]

One thing I noticed on this old thread is that if this engine has the stock TBI swirl port heads you cannot use the roller rocker arms you bought for it, unless you installed push rod guide plates with screw in rocker studs (old TBI heads are not worth that kind of money in machine shop work). Those old TBI heads require self aligning rocker arms. Self aligning roller rocker arms do exist.

 

[sweetk30]

Them ones i got are self aligning note the part no. and pics with the guides on the rollers .

 

[1-ton]

Them ones i got are self aligning note the part no. and pics with the guides on the rollers .

OOPS! did not look at the picture close enough. I remember doing a search for some self aligning roller rockers, and the only company I could find that made any was Scorpion. I did not know that COMP cams made some too.

 

[brut4s]

Update?

 

[sweetk30]

look up to post #35 and that was its end fate . its sitting here on a engine stand waiting for a new home be it junk yard or a person wanting a rebuild project . @brut4s