DIY Valve Reliefs? :)

[caffeine]

Got the top end back together




... just kidding

New valve reliefs visible






Started it up and it runs nice and smooth. However overheating issue remains. It's like the coolant isn't being pumped through the engine at all. Heater core lines will heat up fairly quickly but the hoses going to the rad are still ice cold when the engine is at operating temp. Replaced the T-stat with no change.

My first thought is a bad water pump but I replaced it only 20,000 kms ago or so. Or a really persistent air lock?? I'm gonna try flushing it a little with a garden hose attachment to see if that makes a difference; if not is there anything specifically I should check before replacing the water pump? Pulley still spins fine.

[1988GTU]

You might have some rtv or gasket debris gunking up a passage. Try reverse flowing the system with that t stat out and garden hose hooked up.

[caffeine]

What's strange is that this issue didn't start till after the car had driven a few hundred km. I agree though it could be something blocking a passageway.

[1988GTU]

When you say the rad hoses are ice cold, are they soft or hard (building pressure) ?

Do you have a pressure tester? Try pumping the system up to 16-17 psi and feel the hoses for firmness.

[caffeine]

They are hard, like there is pressure. There's a 20psi cap on the rad and 15 psi cap on the surge tank. Both rad cap and surge tank are holding pressure

[1988GTU]

The reverse flowing of water is what I'd try right now.

[Superdave]

I always had problems getting these engines to burp, I'd suggest the garden hose as well.


Can't really see in the pictures but do you still have the bleeder on the top of the coolant tower on the timing cover? That one is really handy.

[caffeine]

Yes the bleeder is still there and I use it while filling.

[3400-95-Modified]

I've never had an issue burping these engines... and I have the bleeder on the coolant tube leaving the thermostat and one on the tower... there used to be a hose/pipe that went from where the bleeder is near the thermostat over to the overflow tank but I just melted that nipple off and put a second bleeder there. Cleaned up the front of my motor more.

Before


After


Also got an older style tree and used the heater core line that wraps around the back of the motor vs in front of the valve cover.

[carbon]

Where does that older tree come from? I need that for my 3500 swap.

[caffeine]

Ditto that older tree looks perfect for a Fiero. For mine I just cut the stock tree right after a weld bead to shorten it. But I like that other style because it actually points the tube away from the valve cover and gives more room for the hose.

[3400-95-Modified]

I think it came off a 3400 van application...

[caffeine]

Ok so finally the overheating problem is fixed. I'm not sure what fixed it but it isn't overheating anymore at least.

First I did a compression test which checked out fine. Then I removed the thermostat, put the housing back on, put a garden hose attachment on a heater core line, popped the rad cap off and ran water through the system for a while. Also ran it out the surge tank as well. So it basically got completely flushed. Next I started it and ran it till it warmed up (without the t-stat) and it heated up till the fan came on and then cooled back down.

After that I put the t-stat back in, filled it with some coolant this time and reconnected the heater core lines normally. I ran it to operating temp again and the rad fan came on and it didn't start overheating. So that's a relief.

However it's still not quite where it used to be. It's doing this odd thing at idle where the temp will rise past halfway on the gauge and pretty much stay there. However if I rev the engine to 3k or so the temp plummets instantly to about 1/4 gauge. I do not think this behaviour is normal but I'm happy it's not overheating and I'm thinking it could just be some leftover air pockets needing to be purged (and as the WP spins faster it moves them through the system).

In any case, the next step for the car is an alignment and then I will finally put plates on it and begin really working on the tune.

Did a fastback swap to it/painted it, poly bushed the front and rear control arms, and built DIY coilovers on the rear. All I can say is WOW the poly control arm bushings made a HUGE improvement in handling even without an alignment. Car feels WAY more connected to the road now.

[Blacktree]

Wow I love that idle! Do you have the cam specs?

[caffeine]

DIY Valve Reliefs?

Intake 230 .578"
Exhaust 236 .573" lift
Lcl 110
Lsa 112