Pee's in the Vee's

[Mars]

Haha, yeah that's a pretty clever subject isn't it.

I had a catastrophic failure a few months ago with my Fiero, I didn't worry about it much as I wanted to do an engine swap into the car anyways and I was busy with the Camaro, but alas here is what I found.

Tore the valve covers off and EVERY single intake rocker arm showed signs of cracking in the pushrod cup and one of them was actually broken. At that point, I figured my piston to valve was too tight with the new cam. Not a big deal, this was a tired motor. Was a '99 3400 that had about 200+ passes in my old Cavalier Z24 when it was boosted w/ Rotrex.

So, I tore the heads off and found that both the intake and exhaust valves had been hitting the pistons.





I continued to tear the motor down..

Found the timing chain skipped.



Broke some more stuff...





Broke my timing cover (that I was supposed to re-use in my 3500.)

Umm, soo yeah, I just wanted to post that to show the durability of these motors. It's NUTS.

Didn't grenade a piston after all that, unreal. This thing had seen WAY upwards of 7000 RPM more than once, and never did anything but run.

Now I just wonder :


Was there always a Piston to Valve clearance issue ? OR did the thing just skip a tooth on the timing chain thus causing all this damage ? We will likely never know. My timing set was a cheap NAPA replacement, but it was the "larger" pre-99 style. I had it apart about 8 months prior and didn't notice huge wear on it, I figure it was about 4 years old. (200+ 12 sec passes EASILY)

I think there always was a clearance problem, and this caused heavy wear on the timing set, which then caused it to skip a tooth.

The specs on the cam were pretty solid :

Intake Lobe : #3016 - @.006 280 lift - @.050 230 lift - .578" Gross valve lift
Exhaust Lobe : #3037 - @.006 288 lift - @.050 236 lift - .573" Gross vale lift
ICL 110
LSA 112

And slightly longer pushrods were used. (they still appear to be in perfect shape)

So, I have the motor sitting out of the car, and a healthy cammed 3500 ready to go in. (as soon as I get a timing cover for it)

[trotterlg]

I think it would be very very difficult to skip the timing chain a tooth without breaking something no matter how much ware it had on it. Those valve imprints are probably just from floated valves or ones that are bouncing. Larry

[Superdave]

Welcome to the dented piston crew... lol

[Mars]

I had the good 896 Comp springs, or was it 986, whatever, you guys know the ones.

[geoffinbc]

Playdough is cheap. Use some on your next build. It could save you thousands.

[ericjon262]

Playdough is cheap. Use some on your next build. It could save you thousands.

I don't think what Mars did on the Fiero was a "build", I think it was just a motor with a cam right?

Edit: wow, your cam was wilder then the one going in my 3500! DAMN!

[Mars]

When I swapped the cam, I didn't even remove the lower intake, I flipped the engine upside down re-re'd the cam. So I didn't neeed new head gaskets, intake gaskets, ect nothing. Did it on the cheap, just did a 9$ front cover gasket.. I don't really care about the old engine as I wanted to put a 3500 in the car anyways. I desktop dynoed the difference, and it shows 30 ft/lbs right across with a few more HP vs. the old 3400 with a cam anyways. With a 4 spd. stick, it'll be nice gaining the bottom end torque.

I was thinking of turboing the car with some parts that I found the other day. Might happen..

[ericjon262]

When I swapped the cam, I didn't even remove the lower intake, I flipped the engine upside down re-re'd the cam. So I didn't neeed new head gaskets, intake gaskets, ect nothing. Did it on the cheap, just did a 9$ front cover gasket.. I don't really care about the old engine as I wanted to put a 3500 in the car anyways. I desktop dynoed the difference, and it shows 30 ft/lbs right across with a few more HP vs. the old 3400 with a cam anyways. With a 4 spd. stick, it'll be nice gaining the bottom end torque.

I was thinking of turboing the car with some parts that I found the other day. Might happen..

So much win here!

[Mars]

ya, just flip her around, spin the cam once and all the lifters are down, and voila !

[ericjon262]

what about the oil pump drive?

[Mars]

Yup, just yank it.

[ericjon262]

Yup, just yank it.

whoops, forgot about them being on the outside, I was thinking about my LT1...

[ericjon262]

4 speed in your fiero?

[Mars]

yeah. 4 spd stick. I have a 4 puc clutch with a 300% pressure plate. haha. It came out of my Z24.

[Driver_10]

I think it would be very very difficult to skip the timing chain a tooth without breaking something no matter how much ware it had on it. Those valve imprints are probably just from floated valves or ones that are bouncing. Larry

That is EXACTLY how I killed my turbo 3400 that I swapped in my Camaro. I had bent/broken push-rods and damaged rockers. There were also dents on the pistons. I floated valves after a severe miss-shift and the engine spun over 8000rpms. (I had all stock valvetrain and cam at the time)

Made a complete mess of the valvetrain. However, the rotating assembly was fine otherwise. I abandoned the 3400 altogether when I went to a 3500 and later gave the hyper pistons to John to use for another build. They hardly had any of the Moly coating rubbed off of them. They are indeed some tough motors.