ronnieforrester

iTrader: (3)

Do LS engines "push" coolant? Ive had turbo cars before that when the HG starts to fail under boost only, they would push coolant out and not recover/cool back down.


this is my first boosted LS application- I just got the car together and dynoed etc. Ive been driving it around and it will stay at 190 with a 185 stat in it so its ok in traffic and normal driving.

When I start hammering on it the temp will start creeping after a 2-3 WOT pulls up to 205- then a few more pulls will get met 215 and so on- if I make another pull or two the aftermarket autometer gauge which is tapped into the flat spot on top of the pump will start climbing faster and ill shut it down. ( I assume at this point its seeing steam and pegs 240-250 on the gauge since its mounted in the highest part of the water pump and there is a void where water used to be.




I don't want to spend fruitless hours chasing problems and throwing parts at it if its the head gaskets leaking under boost only.


this is the 2nd motor that did this- the first 4.8 only lived about an hour and died on the dyno (rod bearing/craigs list rip off motor) but they are both overheating about the same way.


any thing I can check for ?


as far as air pockets I took the steam tube hose(4 corner steam tubes) off when I was filling the radiator and I have let it run in the driveway for 30 minutes with the cap off to burp any air.



its got a nice new Griffin LS swap radiator in and a nice fan set up that kept my stroker Ford 408 engine at 185 consistently.

it does have a 4" thick intercooler and a tranny cooler in front of it now but no ac condenser.

Realcanuk

How much boost are you running and what head gaskets ?

Slowhawk

iTrader: (12)

If it's decent boost on those stock head bolts I would say it's lifting the heads.

ronnieforrester

iTrader: (3)

15psi - stock 01-ish long block-heads have never been off.

tjwashow

iTrader: (2)

why wouldnt you use ARP head bolts? definitely sounds like your problem

ronnieforrester

iTrader: (3)

have you not followed any of the stock 500-800HP 8 second long block threads on here ?


because the studs will exceed the cost of the engine

SuperC1

iTrader: (4)

You will need some head studs and possibly may need reduce your boost / timing a couple of degrees. Assuming that you are running pump gas, sounds like you are right on the edge of detonation.

ronnieforrester

iTrader: (3)

E85 for fuel- tuner told me my timing was conservative.


I have a friend who is coming by today who has HPT so we can log it- ill see what the timing is and if there is any knock and also cyl head temp.

SuperC1

iTrader: (4)

If you have an adjustable boost regulator you may be able to reduce your boost by a pound or two and everything may just work out fine as it sits.

skinnies

iTrader: (33)

This, when we pushed on stock gaskets/bolts we could just turn the boost down and it wouldn't push any coolant and be fine, turn it back up, would push.

I'd put good gaskets/studs in it, then again we build them to drive and be reliable. With ls9 gaskets/arp studs we haven't pushed coolant with A LOT of boost.

Also have any holes drilled in the thermotat? If not you can do that, fix to help from getting air trapped behind the thermostat.

Ryans99ls1

iTrader: (16)

Had this exact thing happen to me. put 10-11lbs to the stock headgaskets/stock head bolts and they lifted as soon as i got off the dyno. Im on E85 at 19* timing. it would blow coolant out of the resevoir and start getting pretty hot after a few pulls. Threw in ls9 headgaskets/arp head studs and everything is perfect. didnt change the boost or timing at all.

ronnieforrester

iTrader: (3)

I guess denial isnt a river in Egypt. I ordered the $69 KMJ studs and the $35 GMPP LS1 MLS gaskets- Well see how/if they work-


I just couldn't swallow $253 for head studs-

If the Chinese junk fails it will be one on many lessons learned the hard way.

67Firebird455

iTrader: (27)

There's quite a few people running a lot higher horsepower on the Chinese studs, surprisingly. I bet they'll work out great for you, and for $69, they're hard to beat!

a4ls2goat

From what I read, the eBay studs are good. Just don't tighten them over 65lbs.

denmah

iTrader: (2)

i run the kmj studs and they work great, we also have them in the sunbird, and my friend jace is using them in a 6.0 with 23lbs of boost on a 6.0 so lots of surface area there...

do the ebay studs come with a manual? or specs?
i have tightened ARP and KMJ's to 80 and never had a issue.

i would bet it was too much timing causing too much cyl pressure people who tune on e85 are like, ill just throw 8deg at this motor it wont detonate lol.

i ran 21lbs of boost in my friends pickup truck on 16deg of timing for a lonngggggggg time over 650rwhp in the truck, ran 10s, 4700lbs and it never pushed water or got hot.

so i think it might be the tune, or possibly super weak hg or bolt or something that is letting it in....

is it a stock steel gasket or paper gasket motor?

turbocamaro125

iTrader: (3)

I have had the eBay studs to 80lbs 5 times on 1 set of studs and still fine. Had a 4.8 with stock gaskets and eBay studs and 22lbs of boost and was fine. Running a 370 and gonna see how it does with eBay studs and 18-20psi with a pt91.5

ronnieforrester

iTrader: (3)

I think the older 4.8's have a composite gasket.

denmah

iTrader: (2)

the composite gasket i can see being a huge problem at 15psi

ronnieforrester

iTrader: (3)

yep- i hope that its it- i remember bending the corner of it with my thumbnail to see if it was MLS


I ordsered the Pro Comp studs from KMJ on ebay and the ls1 gaskets from summit earlier.

Realcanuk

I would splurge and go with LS9 gaskets.