Overheating issues at the track. Any ideas??
03-25-2010, 12:33 AM
#77
Drifting
Patrick,
All I know is that I've blown a few gaskets under marginal boost conditions prioir to using proper head studs and head gaskets. Proof, no. But here are my 2 cents, or my cliff notes.
What modern steel head studs provide is: Better clamping force, consistent torque, more even clamping force on the head and gasket. The better strength studs allow higher head tq if necessary. They will hold your tq specs much better than was was scrivened from the best of the tool box in 1986 - 1989.
These stronger head studs allow deeper machining on both sides to clamp your head to your block. Deeper studs placement is stronger, expecially when we are asking alum to hold up. Deeper is better in this enviornment.
The steam vent allows your coolant system to consistently bleed off air. No need to wrestle with a 10MM little wrench trying to get air out of a system that shouldn't be creating steam, but our cars under excessive power can get air from many possible locations. It's always been part of the deal. We get the little 10M wrench in the tool kit for many reasons.....Allowing steam to vent into a safe place is a good thing. I never want to rotate that little bolt again on a hot engine. Enough said.
I've gone to Evens coolant, and I still have a steam vent.......just in case.
Our cars despise any air in the coolant system, so keep it vented.
George
All I know is that I've blown a few gaskets under marginal boost conditions prioir to using proper head studs and head gaskets. Proof, no. But here are my 2 cents, or my cliff notes.
What modern steel head studs provide is: Better clamping force, consistent torque, more even clamping force on the head and gasket. The better strength studs allow higher head tq if necessary. They will hold your tq specs much better than was was scrivened from the best of the tool box in 1986 - 1989.
These stronger head studs allow deeper machining on both sides to clamp your head to your block. Deeper studs placement is stronger, expecially when we are asking alum to hold up. Deeper is better in this enviornment.
The steam vent allows your coolant system to consistently bleed off air. No need to wrestle with a 10MM little wrench trying to get air out of a system that shouldn't be creating steam, but our cars under excessive power can get air from many possible locations. It's always been part of the deal. We get the little 10M wrench in the tool kit for many reasons.....Allowing steam to vent into a safe place is a good thing. I never want to rotate that little bolt again on a hot engine. Enough said.
I've gone to Evens coolant, and I still have a steam vent.......just in case.
Our cars despise any air in the coolant system, so keep it vented.
George
03-25-2010, 12:39 AM
#78
Rennlist Member
Thread Starter
Again, thanks. Good info.
03-25-2010, 12:47 AM
#79
Three Wheelin'
Good advice.
The book "Engineer to Win", by Carroll Smith, was published about the time our cars were built. He says:
"I still consider the water system deaerating swirl pot to be an absolute necessity on any racing car."
"A big one (deaerating swirl pot) can save you when a head gasket begins to weep."
"I run a lot of block pressure, usually by means of a venturi-shaped restrictor where the water exits the engine. This goes a long way toward the prevention of hot spots and attendant steam pockets in the cylinder head."
and other gems...
The book "Engineer to Win", by Carroll Smith, was published about the time our cars were built. He says:
"I still consider the water system deaerating swirl pot to be an absolute necessity on any racing car."
"A big one (deaerating swirl pot) can save you when a head gasket begins to weep."
"I run a lot of block pressure, usually by means of a venturi-shaped restrictor where the water exits the engine. This goes a long way toward the prevention of hot spots and attendant steam pockets in the cylinder head."
and other gems...
03-25-2010, 01:14 AM
#80
Drifting
03-25-2010, 01:35 AM
#81
Drifting
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that head stud stuff made no sense George LOL but tell us more about "evans " coolant ..
so the idea behind the restriction is the increased coolant pressure raises the boiling temp.
some guys report better power by means of more boost or timing when using strait Etheline glycol the higher boiling temp mens there is less boiling above the exhuast ports and a cooler head .
so the idea behind the restriction is the increased coolant pressure raises the boiling temp.
some guys report better power by means of more boost or timing when using strait Etheline glycol the higher boiling temp mens there is less boiling above the exhuast ports and a cooler head .
03-25-2010, 03:05 AM
#82
Rennlist Member
Thread Starter
Mikey, that is interesting. I've never heard of a 'deaerating swirl pot'. Especially for the coolant system.
Has anyone ever put one of these on our cars?
George, still don't know. I suspect the H/G but won't know until a day or two more. A matter of fitting in with other cars.
Adam, makes sense to use some fluid with a higher boiling point doesn't it? My assumption is that this stuff is what is available today?
Has anyone ever put one of these on our cars?
George, still don't know. I suspect the H/G but won't know until a day or two more. A matter of fitting in with other cars.
Adam, makes sense to use some fluid with a higher boiling point doesn't it? My assumption is that this stuff is what is available today?
03-25-2010, 03:50 AM
#83
Drifting
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yeh its pretty hard to buy down the street ask Sean to get in 20's from his oil wholesaler . yeh one of fizgeralds cars has that swirl pot .in that acticl i was supposed to send you ..i think the stem vent kit is the best thing for getting the air out as its at the highest piont of the engine
another good idea a saw was a header tank up by the windscreen about 4" higher than the original tank .
hey its not just the poor flow the gunk in the rad would have insulated the coolant from the aluminum so even small volume moving through was not cooled properly
another good idea a saw was a header tank up by the windscreen about 4" higher than the original tank .
hey its not just the poor flow the gunk in the rad would have insulated the coolant from the aluminum so even small volume moving through was not cooled properly
03-26-2010, 08:38 PM
#84
Drifting
update time.
We removed the head yesterday to find the culprit. another Cometic head gasket. the sealing rings around the bores had worn through allowing combustion gases into the cooling system.
I would say its because of 2 reasons, Patrick has run quite high boost in the past on this engine, 1.5bar+. and the bores are most likely moving slightly which may cause the metal headgasket to break through the sealing ring. the good news is that the car is still drivable back to the workshop, if it were a standard headgasket we would have needed a tow truck.
We removed the standard head studs late yesterday, although 2 were quite stuck and needed to be soaked in rostoff overnight. Raceware studs are going in as you can see in the pictures. now we will see if the raceware studs can prevent this failure, or at least let the MLS last a little longer
We removed the head yesterday to find the culprit. another Cometic head gasket. the sealing rings around the bores had worn through allowing combustion gases into the cooling system.
I would say its because of 2 reasons, Patrick has run quite high boost in the past on this engine, 1.5bar+. and the bores are most likely moving slightly which may cause the metal headgasket to break through the sealing ring. the good news is that the car is still drivable back to the workshop, if it were a standard headgasket we would have needed a tow truck.
We removed the standard head studs late yesterday, although 2 were quite stuck and needed to be soaked in rostoff overnight. Raceware studs are going in as you can see in the pictures. now we will see if the raceware studs can prevent this failure, or at least let the MLS last a little longer
03-26-2010, 10:30 PM
#85
Drifting
I had the same issue with my Cometic gasket on my 3.0 motor. Granted, we found some tuning issues. Detonation at number four. The TEC was leaning out on that cylinder. I didn't know you could tune each cylinder and injector....lesson learned.
We decided to use the factory wide fire gasket. Other folks have had issues with the cometic on our cars, and we decided to go with what worked just fine before. We will also get the tuning perfect. I actually had a tiny bit of scoring on #4 and honed all cylinders and replaced the pistons with some lighter units. We also found that the fuel pump wasn't getting a full 14v, more like 10v, so we made a new run from the battery to the pump and tossed the factory wiring. We were thinking under full boost and 500whp, the pump may have helped with the lean issue at #4. Something to measure at the pump under boost, or just lay out new wiring.
At close inspection, did you see detonation issues? Something else to consider, now that all the H20 is out of the system, is Evans coolant. I'm now using this for the first time in a Porsche. http://www.evanscooling.com/
This waterless coolant makes sense, and my Diesel truck runs much cooler under boost hauling my stuff.
Glad it's just a gasket issue. Good luck Patrick. Thanks Jet951 for the update.
We decided to use the factory wide fire gasket. Other folks have had issues with the cometic on our cars, and we decided to go with what worked just fine before. We will also get the tuning perfect. I actually had a tiny bit of scoring on #4 and honed all cylinders and replaced the pistons with some lighter units. We also found that the fuel pump wasn't getting a full 14v, more like 10v, so we made a new run from the battery to the pump and tossed the factory wiring. We were thinking under full boost and 500whp, the pump may have helped with the lean issue at #4. Something to measure at the pump under boost, or just lay out new wiring.
At close inspection, did you see detonation issues? Something else to consider, now that all the H20 is out of the system, is Evans coolant. I'm now using this for the first time in a Porsche. http://www.evanscooling.com/
This waterless coolant makes sense, and my Diesel truck runs much cooler under boost hauling my stuff.
Glad it's just a gasket issue. Good luck Patrick. Thanks Jet951 for the update.
03-26-2010, 10:42 PM
#86
Drifting
First you have to define ‘failure’. Are you thinking that breaking is failing…or is non elastic deformation (yeilding) a failure? How about excessive stretch…or is it any stretch at all.
The ‘worth’ of the ARP or raceware studs is that they can be reused indefinitely. The factory studs are not technically reusable since they are a stretch fastener – but in reality they are fine for several reuses.
The ‘worth’ of the ARP or raceware studs is that they can be reused indefinitely. The factory studs are not technically reusable since they are a stretch fastener – but in reality they are fine for several reuses.
ARP, Raceware, etc. studs can't be stretched, therefore you can tq them to a greater PSI without damaging their strength to a reasonable limit. Isn't this correct?
Once you surpass a stock head stud's tq rating they are stretched beyong any rebound right? Therefore toast, right?
Thanks Chris.
03-26-2010, 10:46 PM
#87
Drifting
update time.
We removed the head yesterday to find the culprit. another Cometic head gasket. the sealing rings around the bores had worn through allowing combustion gases into the cooling system.
I would say its because of 2 reasons, Patrick has run quite high boost in the past on this engine, 1.5bar+. and the bores are most likely moving slightly which may cause the metal headgasket to break through the sealing ring. the good news is that the car is still drivable back to the workshop, if it were a standard headgasket we would have needed a tow truck.
We removed the standard head studs late yesterday, although 2 were quite stuck and needed to be soaked in rostoff overnight. Raceware studs are going in as you can see in the pictures. now we will see if the raceware studs can prevent this failure, or at least let the MLS last a little longer
We removed the head yesterday to find the culprit. another Cometic head gasket. the sealing rings around the bores had worn through allowing combustion gases into the cooling system.
I would say its because of 2 reasons, Patrick has run quite high boost in the past on this engine, 1.5bar+. and the bores are most likely moving slightly which may cause the metal headgasket to break through the sealing ring. the good news is that the car is still drivable back to the workshop, if it were a standard headgasket we would have needed a tow truck.
We removed the standard head studs late yesterday, although 2 were quite stuck and needed to be soaked in rostoff overnight. Raceware studs are going in as you can see in the pictures. now we will see if the raceware studs can prevent this failure, or at least let the MLS last a little longer
I'm amazed that you didn't see your expansion tank didn't blow water out like an open steam vent, or did you? Something else to look closely at now is your radiator leaking. The exhaust pressure does some crazy things to your coolant system. They experienced pressures not intended.
Pressure test your radiator prior to using it again.
03-26-2010, 10:50 PM
#88
Drifting
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well Chris just recently said in my other dead M14 stud thread is you can do a standard stud up until it strip's out the block and the block ...
you may see a tiny bit of stretch but Never failure from standard studs .
you may see a tiny bit of stretch but Never failure from standard studs .
03-26-2010, 10:58 PM
#89
Drifting
I'm not talking about breaking. Factory head studs have a TQ spec to allow you to stretch the metal a tiny bit so it acts like a shock or rubber band. You TQ it to the manufacturer specs and it stretches to allow some give. Once stretched beyond the specs, they are no longer holding their intended tq specs, hence failure.
03-26-2010, 11:03 PM
#90
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Some more interesting facts…
A small block Chevy race engine has about 50psi of coolant pressure in the block – less in the head. This is what helps reduce localized boiling. You need restrictors to do this.
You can run the Evans coolant with the radiator cap off…I tried it and it works.
There have been quite a few different Cometic designs. They are always making improvements…some of the earlier gaskets really needed improving!
George – you need to be running full sequential to really tune the fuel by cylinder.
A small block Chevy race engine has about 50psi of coolant pressure in the block – less in the head. This is what helps reduce localized boiling. You need restrictors to do this.
You can run the Evans coolant with the radiator cap off…I tried it and it works.
There have been quite a few different Cometic designs. They are always making improvements…some of the earlier gaskets really needed improving!
George – you need to be running full sequential to really tune the fuel by cylinder.