ys1civicsi

So like the title states, I have been rebuilding my 91 civic si and it had finally come to the point to start it/drive and it let me down.

I drove it to the shop for inspection, and it overheated along the way under load. Yet while initially idleing it in my garage to check everything it was fine, so this is why I decided to go ahead and take it on its first road trip/start breaking in the motor.

Setup:

91 civic si

Ls/vtec bored to 81.5 mm

Eagle rods/wiseco pistons 8.6:1

Balanced bottom end stock micropolished crank

GSR head 3 angle valve job, slight P/P

Stock P30 head gasket

ARP headstuds

Garrett T3/60-1

SLS mini ram manifold to a custom 2.5-3" DP

EG half rad w/ slim fan.

JG edelbrock manifold.

wastegate spring is out so no boost is built, running Stock basemap for break in (stock injector ECU etc)

Now, the car idles fine, yet once on the road it has absolutely no power and it overheats. Timing marks are on, and it starts right up.

It consumes no coolant, yet when it idles to warm up, I leave the cap off and a stream of small bubbles continues to run through.

I also removed the thermostat and it still overheats.

I shut it off before it cooks, so I do not fuc* it u more, but Iknow work must be done.

Any insight before I go any further would be great.

Headgasket?

Radiator

Help me out guys

Need mor info/pictures please ask

I am here for your help

nowtype

Have you checked to make sure your fan is turning on? Is it blowing/pushing the right way? I'd check to make sure the fan polarity is right.

crxcel

or a air pocket..not sure if you can have one with no thermostat, but mine did it to me with a thermostat. Same symptoms as yours.

boostedteggy718

i say check if ur fan is working or wire it directly to see if it does same thing again

ys1civicsi

The fan is def. Working, now weather the polarity is right or wrong I haven't checked. I have the fan on the back of the radiator so I would want it to pull in that situation correct? No thoughts on a head gasket. Everything is brand new, I'm stumped. No power and overheating....

kyden

i doubt it is the fan. if it was it would overheat at idle.

i would do a leakdown test.

ys1civicsi

this was my next guess, but I have to go out and purchase the unit first.

nowtype

Change the polarity on the fan and see what happens. It's a really easy fix and I still have a feeling it is your issue. It takes a long time for a car to get up to temp just idling. The fact it didn't overheat idling in your garage doesn't mean much to me. Especially if the fan is moving any air from the radiator.

Change the polarity, see what happens, work from there. Remember not to beat on your car at all and monitor things with a wideband. What kind of tune does the actual car have? I suggest you monitor things closely so you don't end up really upset if your car explodes...

TheShodan

iTrader: (14)

I would check coolant. Make sure all the air bubbles are out with the car running and the cap off before a full leakdown test. Go for the "low tech" approach first.

ironcheftony

might be iffy on the headgasket i would have ran an 82mm to be safe, i believe oem gaskets can be used up to 81.5

ys1civicsi

Oem is fine for 81.5mm. I'll get on the fan tonight, and like said above the car is on a stock tune. I talked to Jeff Evans and he said ok/ be fine. Stock p30 ecu, stock objectors, obd-1. The waste gate spring is also removed which will not allow me to create boost, but also enables a huge exhaust leak.l, which may be my loss of power. I also have my wideband installed, so yes I am monitoring that at all times.

Ammadien

Is the wastegate dump to atmosphere? or back into the exhaust?

Nate

95dxsir2

is the head gasket on right?
i learned the hard way of drinking whiskey and working on my car which will never happen again.

ys1civicsi

The dump is to atmosphere, throws some heat, but nothing. Substsntial. I'm going to check the timing ageing. I read if its off it can cause it to overheated but still run. I'm almost 100% positive that the headgasket is on correct.

nowtype

Your wastegate is open 100% of the time. It will result in your engine sucking in nothing but exhaust fumes. This could be a major issue. Go get some flexible exhaust tubing from the local parts store and a wastegate flange and make up a dump tube.

ys1civicsi

It already has a dump as it exits nearly under the car. It may be s slight issue, but I do not think it is completely the problem. I have not had time to actually look ay the car yet, but tomorrow is looking good. Please of there id any more insight on the timing issue please throw me your insight. I am also going to remove the front bumper to see if it is air flow issues. Thanks again guys

Ammadien

I dunno, could there be an issue(at least with the loss of power) with running an open dump on stock ecu/injectors?

It would be similar to running with open headers and no tune eh? Or so I'd think.

Nate

ys1civicsi

This also crossed my mind for the loss of power, as it seems to be roughly 3 cylinders pushing the turbo and one is leaking out the wastegate. Just my thoughts. I'm going to put the spring back in and see if my power 'ones back, and stay out of boost.

turbohatch96y7

iTrader: (15)

I doubt ur waste gate has anything to do with ur problem at all. I would check ur radiator and water pump make sure everything is moving it sounds like ur radiator isn't working efficiently. Unless there both brand new

ys1civicsi

Pump is new, the rad is a stock dual core half rad. That isn't to old

092eg6

if ur depressed u can go to a doctor and ask for depression pills!!

EKlscoupe_98

aren't you suppose to use a ls head gasket and not a b16 (p30) for ls/vtec

Hybrid96EK

Yes. But I don't think using the Vtec head gasket will cause any issues.

littlewagon

Post pics of the setup. Could be something simple that was overlooked.

mikej94civex

idk if i read correctly but u said the wg spring is out...wouldn't that mean the turbo would just spool n spool and keep spoolin since theres no control? thus causing crazy hot wg exhaust to fill the engine bay and also seein how it's overheatin under load is it possible ur buildin boost?