SLP Firebird GT : Build Thread

[CFreed11]

Re: SLP Firebird GT : Build Thread

Made some progress today. I've kind of reached a point where I can't go any farther until I get ahold of a few tools/parts. I need a dial caliper to check my pushrod length, and I need 1 intake plenum bolt. The Upper Intake Manifold on the FWD 3800 has one less short bolt than the RWD 3800, so I've got to find just one bolt to fit.

Didn't take many pics as I didn't want to get my phone any dirtier than it already is, and I just didn't think of taking pics half the time either.

New RollerMaster double roller timing chain and custom Comp Cams camshaft installed:



Engine nearly complete, just a few things left to finish up:





I won't be putting the oil pan on until I get the engine off the stand as I'd like to replace the rear main seal. The engine has 57k miles and there's no sign of the current rear main leaking, but I know it's a common problem and would just like the peace of mind knowing that a brand new seal is installed.

Also, don't mind the old FWD oil filter adapter in the pics. It's just there to keep the valve/spring in and to keep track of the 4 bolts that hold it there.

[techsan23]

Re: SLP Firebird GT : Build Thread

Looks really good so far. Are you using a milled oil pump cover? I realize you had'nt finished bolting up the timing chain in the pic, but you did pop the cam sensor back in the timing chain sprocket, right? Just thought I'd ask. I'm anxious to see the pink and purple against all of that black. It really ought to pop.

[CFreed11]

Re: SLP Firebird GT : Build Thread

I bolted the cam sprocket up and was looking at my old timing set parts, trying to remember if I needed the chain tensioner or not when I saw the magnet on the old sprocket. It was kind of a pain getting it on there with the sprocket already bolted on, but I managed to get it in there. I had to rotate the crank so that the correct hole for the magnet was at the top where the balance shaft gears used to be and work it down behind it and through the hole. It was a pain, but I did get it in there.

Today, I also sorted through a 5gal. bucket full of old metric nuts and bolts at my dads and managed to find a bolt that will work for the upper intake, so that's all bolted and torqued down now. I just hid the mismatched bolt on the backside of the intake.

And I'm still working on the color scheme. Now I'm stuck whether I want to continue with the colors planned, or just stick with black and bare metal. The stripes on the car are silver, so the bare metal would flow with the overall car. But I think the color I had in mind would look good, yet not be too much of a contrast to the rest of the car. We'll see how I feel this week, next weekend the top end gets closed up.

I also picked up all the supplies needed to mount the ICM and coils to the firewall and build custom plug wires again. If I have time, I may try to hide the rest of the wires in the engine bay too.

[CFreed11]

Re: SLP Firebird GT : Build Thread

Oh, and yes, I'm using a milled oil pump cover.

[htmabe]

Re: SLP Firebird GT : Build Thread

When you put the double roller chain on in place of the stock one do you lose the internal balancer which helps with knock retard?

[CFreed11]

Re: SLP Firebird GT : Build Thread

The balance shaft? Yes. You have the option of either disabling it by removing the the drive gears for it and leaving the shaft static in the engine. Or you can remove it completely and plug the hole in the back of the block that feeds oil. I just disabled it and left it in there.

[Docta]

Re: SLP Firebird GT : Build Thread

Yup. Same thing is done to mine. Didn't really have a good way to plug the hole, So I left it. Hasn't done any harm.

[htmabe]

Re: SLP Firebird GT : Build Thread

Imho I'm not sure the advantage of a double roller is worth it. The balancer is of such a small diameter that the loss of rotating mass only equates to about 1 horsepower the equivalent of an aluminum driveshaft. The bigger the rotating mass the more it stores. Horsepower achieved from the reduction of rotating mass only makes it available now rather than an 1/8 mile down the track.The balancer was one of the most innovative design ideas of all time upon the introduction of the 3.8 two. An out of balance motor loses about 15 horsepower which only goes up expedientially with rpm,s . I'm thinking if you want to go after rotating mass hp change the flywheel to aluminum because of it's large diameter it equates to about 15 hp and balance the motor. Not trying to p anyone off just never hear anyone on here talk about it is all.

[CFreed11]

Re: SLP Firebird GT : Build Thread

I didn't lose the balance shaft in an attempt to gain horsepower. From my research, the double roller is almost necessary when trying to achieve the power levels that I'm aiming for. I say "almost" because there are a few out there that have managed big numbers with a single roller, but to me, the safe thing to do was to go with a double roller.

[ssms5411]

Re: SLP Firebird GT : Build Thread

I didn't lose the balance shaft in an attempt to gain horsepower. From my research, the double roller is almost necessary when trying to achieve the power levels that I'm aiming for. I say "almost" because there are a few out there that have managed big numbers with a single roller, but to me, the safe thing to do was to go with a double roller.

I kept my stock GM single chain and will swap over a Rollingmaster single when I do my cam swap in the future. If I start breaking the single chains I'll swap to a double only because their are some people with 130lb to 150lb valve springs that haven't broken any single chains. I've had the Comp 130lb springs for about 3 years now with no problems but it doesn't get driven but once a month. I do have a double roller chain on standby though.

[htmabe]

Re: SLP Firebird GT : Build Thread

Right on. Can't argue with safe. I've blown 7 motors and it's ALWAYS traced back to the valve train, always. With that being said it then traces further back to a valve spring. All 7 blew above 7000rpm but never had a problem with a timing chain. Never even thought too much about the thing to be quite honest. Motor number 8 has been in the car for 2 years now which is twice as long as all the others. The difference being I check and maintain the valve springs. Speedway sells a tool where you can check spring tension in the car. I also have the other tool that bench checks em. Rule of thumb is record what the tension is when brand new then after break in you lose about 10% but they should stay there at their "broke in state". If any go to 15% of new replace em all. Just something to think about if your gonna be running in the 7000 rpm range. I'd even say 6000 for that matter. 6000 is when you feel the power loss and valve float. 7000 really lets you know things are getting a little out of control. Also learned when it comes to valve springs you get what you pay for so not a good place to try n save a buck or two. Good luck on your build and I enjoy reading about your progress. Kinda makes me feel a little more the norm vs. extreme to know others are tearing into their motors trying to squeeze that last hp out of it. If I can help out I'll be sure to chime in what I've learned from the school of hard knocks. They don't call it the ticking time bomb for nothing.

[htmabe]

Re: SLP Firebird GT : Build Thread

Just a note, those heavy 150lb springs consume hp .Again it's back to that safety factor on valve float / overlap . I use what's recommended x 10% figuring after break in I'm where I should be. Couple that with high quality springs and a maintenance schedule. So far that's worked for 2 years counting . This season just started 2 weeks ago and she s running strong. I'm not out buying groceries I'm trying to go as fast as I can. I'm not gonna give up any hp to anyone .

[CFreed11]

Re: SLP Firebird GT : Build Thread

Thanks for the tips and perspective. I'm always open to other people's opinions and point of views. And I appreciate all the help I can get. This engine won't be raced very often, maybe a trip to the strip once or twice a year to see what the car can do. I do plan on taking it to some open track days at a local road course though. Straight lines aren't really my cup of tea, but I love powering through some corners.

I did check my pushrod lengths Sunday night against the stock 7.050" rods and a set of 6.950" rods that I already had from before, and it looks like I'm right on the edge of 6.950" or 7.000". The 6.950's are JUST inside of the center of the valve stem, the 7.050's were on the outside edge of it. I think I should be alright running the 6.950's since they are so close.

[ssms5411]

Re: SLP Firebird GT : Build Thread

I was reading a article on ZZP's site about pushrods, they say stock is 7.02 and that the reason Comp lists them at 7.05 is because of where they measure them at different points. I'm surprised they are shorter since your using stock .062 headgaskets. I think I'll measure mine when I tear into it.

[CFreed11]

Re: SLP Firebird GT : Build Thread

I did a quick search when trying to figure out what stock size was. The first link that came up (I believe it was 3800pro iirc) said they were just shy of 7.050, which is Comp cams stock replacement. So that 7.020 sounds right then.

The heads have been milled .020" so that's probably why I came up with 6.950-7.000 to be the correct length for me. I don't know if that math correlates from one to the other exactly like that, but if you subtract that .020 that the heads have been milled from the the stock 7.020 pushrods, you come up with 7.000. From when I checked my pushrod lengths, a 7.000 would likely put me at the exact same spot on the outside of the center of the valve stem as the 6.950 gives me on the inside of the center. If you were to measure the valve stem from 1-10 with 1 being the inside most part of the valve stem and 5 is center, the 6.950's put me right in the 4-5 range where the stockers put me in the 7-8 range. I probably just made that sound way more complicated than it really is...lol