L67 F-bird

[thebeewantsboost]

Re: L67 F-bird

stock the best i could run was a 10.2 1/8 which converts to a 15.91 1/4 damn. sounds hella slow. i'm scared to run now lol.

[Gutless]

Re: L67 F-bird

Bought a set of Hoosier radial slicks and the car hooks now! Best 60ft of 1.93 which is just a 1100 RPM stage to load the driveshaft and rear up and stomping on it when it goes green. Tried staging it at 2500 and higher but it would be slower the higher I staged it at even though it never spun.

Ran a best time of 14.40 at 96MPH with a 2.00 60ft. My other fast runs were 14.46 and .48. Im able to duplicate the same time back to back and for the first time Im not dissapointed with how the traction issue went so its time for more power! In order of whats happening- Billit fuel rails, headers, converter, cam, 80lb injectors, CORN!, 2.8" pulley. Shooting for low-mid 12's daily winter driven in Minnesota/North Dakota winters. Yeah im sorta nuts. I should worry about paying for my college a bit more.



Ohh, by the way, the car number was F231 :excited: Dumb luck cool!

[Gutless]

Re: L67 F-bird

So after I raced I developed lowish oil pressure. The needle on the GM gauge started staying around 30 instead of 45-60. Saw the gauge bottom out once and thought the sender was bad so I hooked up a mechanical gauge to check and it was low. Cold idle/cruise is 50 and hot idle is 5 and cruise is 20. Sent an oil sample to get tested and the aluminum levels are elevated but it's not severe which surprised me.

Now I gotta decide if I's just going to drive it this winter and wait til spring to do the bearings, rebuild it this winter, or buy a long block and run that. Decisions.....

[techsan23]

Re: L67 F-bird

Maybe just tear off the timing cover and do an oil pump?

[Gutless]

Re: L67 F-bird

Thats what Im almost leaning towards. High aluminum content leads me to believe something is messed up in the oil pump and it scoured the housing really bad. Has anybody else ever had that problem?

I know its a big issue in first generation 70's-80's 3.8's but I always thought the issue was resolved when they went to the different oil pump design.

[Pewter02Camaro]

Re: L67 F-bird

I wouldn't say it's out of the question, the kits are cheap and if you do rebuild you can inspect the front cover real good and replace if clearences are bad. Err on the side of caution.

[Gutless]

Re: L67 F-bird

Yeah, the rebuild kits are only $200 and the engine has 180K on it so it certainly couldn't hurt. Biggest problem is finding the time to do it. Im sure bearings, gaskets, and re-ringing the block would be fine.

I wasnt planning on taking the motor apart until next summer. Wanted to just take the motor out this winter and put my headers, stall and fuel rails in. Didnt want to take the motor apart twice and then put the cam and port the heads later.

Its up in the air still.

[thebeewantsboost]

Re: L67 F-bird

outta curiousity how many miles are on that motor? and was the oil pressure low before?

[Gutless]

Re: L67 F-bird

It had 170,000 when I bought it and I have 15K on it now that I think so it has 185,000. Purchased it out of a rollover. Oil pressure was great when I bought it but I noticed around late August it didnt seem as high as I thought it was but didnt think about it much until October when it never got above 30 when hot.

Its either bearings or the pump.

[Gutless]

Re: L67 F-bird

I had the week off for spring break. First day it was above 25 this week (weather sucks this year, 3ft+ of snow and 2 days in March above 32) so I pulled the engine. Lost oil 20PSI of oil press in November and have just ran it. Sent the oil in for a test and there was high aluminum content so I didnt know what to think. There was little shreads of steel and some glitter in the oil filter.

Damn thing fell right out. Took 2 1/2 hours and it was out. Spent 1/2 hour trying to get the driveshaft out. Was rusted and stuck to the rear end U joint. Once that got knocked out everything else came out pretty good. Only broke 1 bolt and it was a manifold to crossover bolt and I just got headers ordered so no worries.

Got the trans off too. Pulling heads tomorrow to see if I killed a lifter or what caused steel shavings to get in the oil.

[Gutless]

Re: L67 F-bird

So the mystery is solved to a point. Turns out the timing chain tensioner came apart and kinda caused some havok. Half of the tensioner was still there so the timing chain was tight but im sure it bounced around at higher rpms. The oil pump sucked parts of the tensioner through it and chewed up the front cover and pump pretty good. Bad news is the crank is out of round .013 on the front main but the rest of it looks great. Bearings really werent bad, they are wore for a 190K mile motor but not bad, they are pitted though. Must have ran more antifreeze through it than I thought at one point. There was white foam on the valvecovers and quite a bit in the pan. Im not sure if a head gastket was seeping or what but there has been antifreeze through the bearings for sure.

Good news is the valvetrain looks great and the cylinder bores have no wear at all. Rings and some cleaning on the pistons would make it brand new. Pretty clean too, guess thats what running alky gets ya. Was hoping that it killed a roller lifter since I planned on replacing the cam anyways. Not sure if im going to cheap out and re run the stock lifters on the new cam, run the stock cam, or buy lifters too. Wasnt planning on gettings a new crank and front cover so it kinda ruined the budget since ive still gotta buy injectors, fuel system parts, rering and bearing kit, cam, blah blah..... Just blew quite a bit for headers and new tires for the car too so it depends on how deep into the build I want to get.



Pile of parts. Should have cleaned the work bench before I took the motor apart but ohh well...

[ssms5411]

Re: L67 F-bird

So the mystery is solved to a point. Turns out the timing chain tensioner came apart and kinda caused some havok. Half of the tensioner was still there so the timing chain was tight but im sure it bounced around at higher rpms. The oil pump sucked parts of the tensioner through it and chewed up the front cover and pump pretty good. Bad news is the crank is out of round .013 on the front main but the rest of it looks great. Bearings really werent bad, they are wore for a 190K mile motor but not bad, they are pitted though. Must have ran more antifreeze through it than I thought at one point. There was white foam on the valvecovers and quite a bit in the pan. Im not sure if a head gastket was seeping or what but there has been antifreeze through the bearings for sure.

Good news is the valvetrain looks great and the cylinder bores have no wear at all. Rings and some cleaning on the pistons would make it brand new. Pretty clean too, guess thats what running alky gets ya. Was hoping that it killed a roller lifter since I planned on replacing the cam anyways. Not sure if im going to cheap out and re run the stock lifters on the new cam, run the stock cam, or buy lifters too. Wasnt planning on gettings a new crank and front cover so it kinda ruined the budget since ive still gotta buy injectors, fuel system parts, rering and bearing kit, cam, blah blah..... Just blew quite a bit for headers and new tires for the car too so it depends on how deep into the build I want to get.



Pile of parts. Should have cleaned the work bench before I took the motor apart but ohh well...

Its good you found it out before the motor blew.

[Gutless]

Re: L67 F-bird

Im mostly glad I found out what caused the low oil pressure. I dont think it would have blown. Pretty sure the oil pressure would have just dropped enough when it got hot this summer and probably spun a bearing or started knocking.

[Gutless]

Re: L67 F-bird

Some updates-

Heads were cracked between the intake and exhaust seats and the exhaust seats were pounded out so I had the machine shop put in new inserts. Honed the block and turned the crank down since I got a replacement that wasnt much better than what I had in the beginning but at least it was usable.

Got 60lb injectors, ordered a S1x cam, got ls6 valvesprings, building some custom aluminum fuel rails, got a LS airlid setup and stuff, 1 piece driveshaft, pacesetters, and a few little things.

Still need to order my rings, gaskets, and bearings. (3800 rebuild kits are stupid expensive compared to everything else, can do an entire 455 Olds for $200 but its $320 for a 3800???) Summit had it cheaper by $100 than EVERYWHERE else but it was on backorder for over a month and said screw it, going through somewhere else. Also need to get my Vette fuel press regulator/filter, fuel system parts, Wideband, and whatever little hoses and clamps I need but its getting closer.

Done with the semester on Thursday so I will actually have time to throw the fireturd back together.

Had a 3400 stall LS1 PTC converter I got not doing any research but since 3800's are 60degree motors everything is different so im stuck with that. If anybody wants it its yours for $450. Has a few thousand miles on it only. So now im stuck with the stock verter. No big deal but would have made it run low 12's probably.

[WarShrike]

Re: L67 F-bird

3800s are 90° motors, just FYI.

The earlier cylinder heads had a propensity for cracking between the valve lands.