'95 Buick Roadmaster Estate 'Wagon on a Whim' - $2015 Aristocrat Edition

Thanks for the lesson on LT1 heads. I knew nothing about these motors before we picked up our Camaro.

Our cam is the Comp 503 which is .503/.510 lift with 1.5 ratio rockers, so its a little more mild than yours. We got a great deal on the cam and a new timing set on Craigslist, which is why we chose it.

You're springs look to be superior to the ones we went with. We bought TFS-16314-16 springs from Summit. They're REALLY CHEAP and were a 'drop in' to our motor with the stock valves and didn't require any machining or shims: http://www.summitracing.com/parts/TFS-16314-16

So far we're happy with them, but we haven't started to beat on the car yet. They support up to .550 lift and have a much higher spring rate than the stock springs, so if we find a deal on 1.6 ratio rockers they should* still work for us. I'm not sure if we're going to upgrade the rockers or not. We're still deciding how to spend the rest of our budget.

I'm learning a lot from following your build, keep up the good work! Its cool to see someone else doing an LT1 car for the Challenge.

I like having someone else out there facing the same challenges. Looking forward to the race! I just hope to shed enough weight to keep up with you guys.

In build news, I started porting the cracked head for practice. I have one cylinder complete. There are some nasty casting marks in the bowl just above the valve seats, both intake and exhaust. Smoothing those out is said to have a very noticeable effect. The finger test approves this method! So much smoother now. I am also rounding off the sharp machining marks on the valve guide bosses and gasket-matching the manifold ports.

I stopped after one cylinder because science.

I want to see if I'm actually making an improvement. Purely A-B comparison, so don't expect any real CFM numbers. Much, much more to come.

Did you make a ghetto flow bench? I am sooooo jealous, ive always wanted to try my hand at porting some heads and ive been lookong for a way to rig something like this up

Well berkeley. Here we go:

I tried torquing my new threaded rocker studs in to the recommended 50 ft-lbs. Most of them went in fine, but 5 of them made a nice "TINK" sound well before spec torque, opening up a crack on the rocker boss A quick search reveals this is a common problem when modifying Vortec heads (almost the same casting to my iron LT1's). So I sanded the crack clean with my new porting equipment and filled it in with the ol' TIG welder. I torqued a stud back in and heard the same TINK which is my weld cracking. I figure the weld is too brittle to handle that much stress. This time I torque the stud in lightly, TIG'ed it back up more generously, then torqued it up to about 35 ft-lbs. No "TINK" this time.

So I think I'm in the clear. Worst case is the rocker boss cracks again, the stud rips out, the rocker falls off the pushrod, and that valve just stops opening. No catastrophic damage and I'll be forced to find a set of aluminum heads like jmk015 is using.

Here's on of the cracked bosses

Here's my E36 M3ty weld repaired heads with all the studs in (for now)

Looks like the threaded stud is bottoming out incorrectly. It should fit, the flat of the hex to the flat of the boss, looks like the threaded stud has a large radius, need to counter bore or counter sink the boss to match. Don't torque until the stud fits flat. The picture shows a gap on some of the others.....

You're right, the bottom face of the hex is not flat on the bosses. Perhaps the stud is acting like a wedge, forcing the hole open. I'll try a countersink and re-torque tonight, probably double check all the welds and go over them again.

This is a great project, would be a real shame to have the motor fail over a minor fit-up error.

True grass-roots, taking something not wanted and making something great out of it!!

Sounds like you need to grind off the ends of the studs being screwed in. The wedging of the rocker boss is exactly what is happening from the stud hitting the bottom and you trying to tighten it more. This will cause a wedging effect from the threads tightening down and pushing the boss out of shape until it breaks. But you already have figured this out first hand.

I've been there done that with some lighting fixtures we were installing. Not fun at all trying to fix that.

So the countersink didn't work, which means the stud was bottoming out. Weird, because I know for certain the exhaust stud holes go into the coolant jacket, while the intake holes go into the intake port. Maybe the hole geometry changes that far down. Instead of grinding 16 hardened steel studs, I threw some washers on that I had lying around.

Now all studs are confidently torqued to 50 ft-lbs and waterproofed, this time with NO audible/visible cracks! My welds seem to hold up now that the prime loading in the stud boss is compressive rather than tensile hoop stress. My day job has taught me that cast materials REALLY don't like tension.

Little better weld:

Chamfer + washer = all the torques

2 thumbs up for this nifty little stud extractor/tap guide tool. Threads tapped in relatively straight.

In other news, GhettoFlo 1.0™ bench just got more sophisticated. I figured out how to precisely open the valves to specific values using the original rockers and a conveniently sized piece of wood. Now I'm just waiting on an actual not-measuring-tape dial indicator to arrive before taking baseline measurements tonight. This weekend should be full of porting!

Will the washers do anything to the rocker geometry? For some reason I think they might.

In reply to Dusterbd13:

They shouldn't. The washers just change the effective height of the stud. The rocker installed height is set during lash adjustment with a nut.

Now, if my tap job was botched and I had the rockers at different angles, that would definitely affect valvetrain dynamics. Hence the tap guide block.

Last night some friends took apart the engine while I fiddled around with GhettoFlo 1.0. I am having trouble sealing the deck consistently, but I have some ideas to make it work.

So here's the bottom end.

• Hones are visible but faint on most cylinders.
• Cylinder 5 has scuffing.
• All bearings look good. Very light wear for 250k miles.
• Crankshaft surfaces are beautiful.
• Piston 5 has skirt scuffing and slight steam cleaning.
• Connecting rod 5 is a banana...

It seems the cracked head (remember way back?) did more damage than I thought. The crack was between 3 and 5, but all the water attacked Cyl 5. Stupid Newtonian fluids, not compressing well! I'm surprised how strong it ran like this. I was autocrossing the day before pulling the engine...

So I need a new conrod and piston, but I can't find stock replacement rods anywhere. I guess it's craigslist and eBay...

Aaaaah just chuck it up in a vise and bend it back with a pair of Channelocks.

It always amazes me that the force is enough to damage the rod and not the crank or the bearing journal's etc...

Double shear vs column loading.

Wow... that's a bummer!!! I bet you can get a cheap rod from an LT1 at your local pull a part yard.

Even better, Stand_D had a stock set lying around from a past Challenge car, so I traded him for a sway bar I picked up at the yard that I won't end up using.

In other news, all bearings are well within spec tolerance but I'll replace them anyway. I have a big Rockauto order coming soon with gaskets, bearings, rings, timing set, and a few misc bits.

Looking forward to seeing how this family cruiser goes after all this work!

Got the crank out, blocked degreased, and bores honed. I used a Flex hone or "dingleberry" as they call it. Put the cordless drill on the slow setting, sprayed everything with WD40, and spent about 30 seconds on each bore. #5 took a little longer due to the scuffing from the hydrolock issues, but they all look better than before. Followed it up with a hot water/dish soap cleaning and coated with more WD40 for corrosion protection.

We had another team work night on Saturday. The fittings for the ABS pump bypass are partially done. All of the exhaust is removed...yes, all 4 mufflers plus 2 cats and a few lead "ballasts" for vibration damping I assume. Tons of weight savings opportunity in exhaust. We also removed the front bumper support, which easily weighs over 50 lbs, and the rear seats. I need to get a scale so I can measure all the weight we're dropping.

I am also 50% done porting the heads. I gave up on the GhettoFlo bench for now. I was able to achieve consistent, repeatable measurements thanks to a head bolt pattern template base plate, but the precision is too low to measure any discernible difference due to my porting. Which means I probably suck at porting or I need a stronger vacuum and more precise manometer.

If you want to do some porting, there are a few threads on thr fbody sites were lloyd elliot mentions were the gains are in self ported heads. IIRC it the floor, short side of the turn, and the valve guide.

Definitely worth a read if you want to try some home porting

In reply to Opti:

Thanks, I think I've read through some of those threads. The valve guides are indeed machined really sharp as you can see from the 3rd pic. They are much smoother now, almost tear-drop shaped. The bowl has a hard sharp edge less about 1/2" from the valve seal. You can really feel the difference with a finger. That ridge alone is supposed to be worth a few CFM. This is kinda fun.

So i found some cliff noted someone made of what lloyd elliot said about lt1 heads. I had it backwards. Work on the roof and leave the short side alone.

Porting Instructions

INTAKE: · Narrow the intake guide boss, · widen pushrod pinch, · make bowl larger, · raise the roof as much as possible, · straighten thewall between the intake ports and if you have little or no porting experience · do not touch the shortside at all. There is CFM to be gained if done correct but there is more to lose if not done correct. If you really know what to do to the shortside you are probably not reading this post anyway.

EXHAUST: · Narrow the guide on the exhaust, · widen the port above the shortside and you can · enlarge the header flange slightly but make sure not to get it as large as the gasket. Theer is also a small bump on the shortside of most LT1s and if you can · remove the bump with out lowering the floor and make sure the port goes strait up from the seat before the gradual turn. Just remove the bump only. If you can not remove the bump with out lowering the fkloor than leave it alone.

Do these things and get the best valve job that you can afford. The LT1 heads are so choked up that almost any porting will show some performance gain. If you are after XXX amount of HP or CFM you might not get it on your first set, If you jut wanna do them to do them or will be happy with 10-20 HP (depending on your skillz) increase than you can probably get that. There is more HP in the heads if done correctly but as I mentioned, If you are reading this (and learning things) you will probably not see the 35-60 HP (depending on mods) gain that is possible with other heads.

Porting is all done. I narrowed all guide bosses, smoothed and widened the bowls, widened the pushrod pinches a bit, and gasket-matched the intake ports to the manifold. I swear my porting looks better in person than in these crappy pictures. Also lapped the valves and started installing the new valves springs. I had some friends help on Saturday to get the crankshaft, pistons, and rods installed with all new bearings and rings.

It's all coming together!

After many troubles with POS parts store spring compressors, I finally got the valvesprings installed. Since my springs are dual and electro-polished, the overhead screw-type wouldn't grip the coil and keep sliding off, shooting my retainers everywhere. The giant C-clamp compressor was actually BENDING under load, thanks to parts-store loaner tool quality these days. The valve clamp was becoming misaligned with the valve under pressure... I nope'd right outta there. I do NOT want a valvespring stuck in my stomach.

So I made my own crow-bar type compressor from a piece of a bed frame that came with my garage. Worked like a charm. Just clamp the head down to the table, tighten the rocker nut, and push that spring down with much better sense of security.

Nice, inventive solution!

by the way, your build here has got me looking for one of these now. Very Cool