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Major top end overhaul, some questions

1098 Views 11 Replies 5 Participants Last post by  josh89
This all started, innocently enough, when I noticed the typical sheared manifold bolts on my heads. This car being my daily driver, and wanting to minimize downtime, I started accumulating parts to do a straight out swap of the heads one day over a weekend.. Well, one thing led to another, and I'm now wanting to address a ton of little issues in one shot.

The goal with this particular motor is to have a the best "slightly tweaked" stock LT1 possible. Which is why, while I've tweaked the heads a bit to breathe easier, I'm not putting a cam in while I'm at it or porting the heads, etc.

The work, as it stands to be done, is as follows:

Replace heads (rebuilt spare set, cleaned, magnafluxed, beehives, 1.6 rollers)
Replace intake (polished the fins to a mirror finish on spare, cleaned out)
Replace all vacuum lines with silicone
Replace waterpump (original @ 150k miles)
Replace optispark (original @ 150k miles)

I figure, in order to avoid running back to the parts store every 20 mins, I need the following:

-complete gasket set - whatever I don't use can go on the parts shelf
-head bolts
-LT1 silicone vacuum lines
-sealant for the front/back of intake
-waterpump/optispark mounting bolts
-manifold bolts
-plugs, wires while I'm at it - Coil is already pretty new as part of another troubleshooting venture.
-New EGR valve (throwing code 32, solenoid is new, and cleaning didn't help)
-thread sealer
-oil
-coolant

-beer

So here's the questions:
- Have I thought of everything parts wise?

- For the intake, I know my current one is doing the typical oil leak at the back. Would it be beneficial to machine a small channel on the rear edge of the intake for the sealer to have more to bite on to when I put the new intake on to avoid it leaking again? Or is making sure I have adequate coverage good enough?
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How about new seals for the steam pipes that attach to the back of the heads. Do you keep helicoil sets for those stripped bolt holes you run across. Aluminum is famous for people over torque, or cross threading fasteners and bunging up the threads.
How about new seals for the steam pipes that attach to the back of the heads. Do you keep helicoil sets for those stripped bolt holes you run across. Aluminum is famous for people over torque, or cross threading fasteners and bunging up the threads.
Seals wouldn't come as part of a full gasket set? Good to know if so..

As for my heads - I should've mentioned in the post, but I drive a 94 Fleetwood. Both the heads on the car and the replacement set are iron. Would it still make sense to use helicoils?
dont forget the shop supplies. i always forget the shop supplies when im doing a 'stranded till it's fixed' job. rags, sandpaper, wire brush, various solvents, greases, rtv..

ring terminals, butt connectors, shrink tube.. you're bound to find a sketchy wire or corroded terminal while you're taking it apart. dielectric grease for every single electrical connector you take off
While cast iron is less prone to bunged up threads, it does happen and the helicoil will work on those also.

And I forgot to say, your correct, the steam pipe seals don't come in any gasket kit that I've seen.
While cast iron is less prone to bunged up threads, it does happen and the helicoil will work on those also.
Thanks, I'll look into grabbing some.

Steveo - Been there.. I'm now well stocked in that area lol
I recommend going to 0.026" head gaskets and bumping the compression while you are in there. Its one of those things that really pays off later if you ever cam it. Also, I would personally steer clear of beehives, there just have been too many failures lately. I would at least get something with a damper because if the outer spring fails, the damper can possibly keep the valve in place and not jack up the rest of the motor immediately, since these are interference engines.

I dont know if you have headers yet, but while the exhaust manifolds are already unbolted, throw on a set of used headers. 3/4 of the battle with doing headers is getting the damn exhaust manifold bolts off.

If you already have another set of heads and intake, might be worth it to do some reading, like what VIPER has been posting about, on how to port and clean up your own heads. Yea it will take about 8-12 hours, but its another one of those free-ish "while you are in there" things.

Id do the free mods while you are in there too like the throttle body bypass and the ICM cooling mod.

Dont forget to rip that opti apart and loctite EVERY SCREW. Also put a bead of RTV around the case as you put it back together.

Drill and tap out the weep hole in the new waterpump and put in a 90 degree brass fitting with a piece of tubing that will allow it to drain AROUND your opti should it ever fail. One of those things I wish I would have done while I was in there...

On your heads, its kinda simple but I would take a dremel and a little stone or cutter or a small circular file and clean up the oil drain back passages of casting flash and sharp edges.

Since all the shit on the front of the motor are already out and the manifolds, do some poly motor mounts and a poly trans mount in place of your surely sagging stockers.

Thats all I can think of right now.
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Great tips! Thanks..

I found Viper's thread (for those that stumble onto this in the future, here it is.. http://www.ls1lt1.com/forum/lt1-%7C-lt4-%7C-l99-engine-tech/55551-budget-home-porting.html )

I have the ICM cooling mod on my current heads using washers, but I'm going to try a greater spacing using tubing and longer bolts when the time comes..

TB coolant bypass is in the cards when I put it back together, but I hadn't thought of doing preventative maintenance to the new opti..

Looks like I have a ton of work to do before I do this..

Realistically though, assuming I've done all the prep work ahead of time, there's no reason I can't do this over a weekend right, barring some major unforeseen problem like shearing bolts, etc..?
As long as you get all the dremel work done ahead of time you'll be fine.
Good stuff - If beehives are prone to failure lately, what would you recommend for valve springs assuming a stock cam and 1.6 Comp Pro Mags rollers? Wouldn't mind the security of dampers if it isn't too much overkill.. I seriously don't expect to be pushing much more than an extra 20-30hp over stock.
So now that most of my questions are answered (thanks guys!), that leaves the intake rear leak prevention idea i had - would routing small grooves (1/8th inch deep or so..) in the front and rear help at all to get the sealant to really stick in there and get a stronger seal?
hey poda, Im located in toronto and am also doing the complete top-end.
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