Factory Five Racing Forum banner
1 - 20 of 44 Posts

·
FFCobra Fanatic
Joined
·
7,022 Posts
Discussion Starter · #1 ·
I will post Dyno sheet and Dyno video later.

First pull make sure everything was ok. 250RWHP.
Second full pull things were still ok. 300 RWHP.
S/C belt needed tighting small coolant leak from around inlet of radiator.
Third full pull now this is when it when BAD. 5500 RPM. 356.29RWHP and 333.01 RWTQ

At 5500RPM steam started filling up the engine bay from the front of the motor? I was videotaping so I am not sure the location it was coming from. Dez stopped the run as soon a he seen the steam cloud. Looked at the Engine bay could not see anything leaking. Coolant all over the place. Let the engine cool down, resarted it everything was ok, shut it down. Restarted it again same steam looking gas coming from drivers pipes. Dez says head gasket. Was able to drive the 10 mile ride home. Any idea how the coolant leek occured? Drove the car home with no problem, no leak? Is it possible for something to leak at full pressure and not under normal drving. I am going to perform a pressure test on the coolant system. Also going to pull the plugs.

John

[ February 21, 2007, 07:18 PM: Message edited by: Cobra 302 ]
 

·
Registered
Joined
·
1,030 Posts
John,

Holy crackers! That sucks! :(

I can't help with your question but hope you get it all worked out soon...

Dave
 

·
FFR Craftsman
Joined
·
5,834 Posts
Sounded like you had a good pull going when it decided to hemorage. Sorry to hear.

I just got home from my dyno as well today. I'm updating my post right now with the results.

Sorry to hear about the head gasket. :(
 

·
Junior Charter Member
Joined
·
382 Posts
My 302 does the same thing. Coolant comes from overflow tank because exhaust gas leaking into coolant. I did a leak down test after removing thermostat and filling goose neck to full. The number 3 cylinder was leaking air into coolant because it was bubbling from goose neck. The head gasket has a leak, when you push RPM.

Frank
 

·
Banned
Joined
·
7,701 Posts
Yes, it is possible. My car did the same, while not boosted.

The coolant system would pressurize the instant I would put my foot in it, and coolant would spew out around the fill cap and overflow can. It was the driver's side head gasket. While driving responsibly, no coolant issues whatsoever.

From what I've been reading, blowers are hell on head gaskets. Did you have new head bolts and gaskets when you put your blower on, or are the bolts/gaskets well worn?
 

·
FFCobra Fanatic
Joined
·
7,022 Posts
Discussion Starter · #6 ·
I never pulled the heads off.
This motor was from the donor.
It was rebuilt not that long ago from a local speed shop. I am pulling the plugs tonight and see what I find.

Would a coolant pressure tester find the issue, or wous this happen only under boost?

I don't want to pull the heads unless I am sure that is the proble.

John
 

·
Senior Charter Member
Joined
·
613 Posts
Sorry to hear about your misfortune. I have been following your posts as of late seeing as though I just installed a KB blower on my car. I am planning to take it to the dyno when the weather is better.

Where did you have the runs done? I don't know the name Dez, but I was planning on making the trip down to MPE racing.

I took the car out today for the second time since the install. Have only gotten on it a couple of short runs and so far so good, but I too am dreading the head gasket blowing.

Good luck.
 

·
Banned
Joined
·
7,701 Posts
Pressure tester and compression test likely won't reveal anything; it didn't in my case.

My problem was that I reused the stock head bolts when I rebuilt my donor motor. I used a very expensive Fel-Pro head gasket, too. But the stock head bolts are a one-time use. When I put the engine back together and torqued the head bolts to spec, they actually weren't tight enough, and the heads would effectively lift off the block under high-RPM (high pressure) situations, and allow pressure into the water passages, thus pressurizing the coolant system and spewing green goo everywhere.

Using a blower amplifies that problem even more, as you are only adding more pressure in the cylinders to lift the heads.

I'd suggest new head bolts and good head gaskets. No other way around it. I farted around with my coolant issue for literally months until I bit the bullet and did the teardown. Sure enough, blown head gasket.

The Fel-Pro gaskets I used are the 1011-2; they are a bit cheaper in the latest Summit catalog compared to what they used to be: $31.99 each.

If you are going to keep a blower in your car, you should probably do the right thing, and get really good head gaskets.

For what it's worth, I looked into putting a blower on my donor motor, and after talking to lots of folks on this forum and in other places, precious few of them have never replaced head gaskets. Seems the low boost blowers (5-6PSI) can sometimes keep out of trouble, but anything above than on a donor motor and it's head gasket time.

There's a local Cobra owner with a fairly high-boost blower that's changed out head gaskets upwards of a half-dozen times.

Bad news, but once you get after it, it's a pretty easy task to change the head gaskets. It took me 2 hours to teardown and 2.5 hours to rebuild. Don't forget all new upper and lower intake gaskets, too.

Sorry, man. I feel for you.
 

·
FFCobra Fanatic
Joined
·
7,022 Posts
Discussion Starter · #9 ·
Dez is in front of seekonk speedway.
I know alot of guys who have used him.
I am not taking anything away from anyone else.
Another reson is that he is close to me. So I was able to drive it home.

John
 

·
FFCobra Fanatic
Joined
·
7,022 Posts
Discussion Starter · #10 ·
Thanks for the advice. It really sucked seing all that coolant/steem on the last run. I don't have a problem changing the head gaskets. It's reinstalling the valvetrain that has me uneasy. What I think I am going to do is get it appart and have Dez reinstall just the heads and valve train. I will finish the top end.

I have the receipt for the motor and the bolts were ARP, and they had new gaskets? I will buy a really nice set so I don't have to deal with this again.

Another question what what are the chances the head bolts backed off from the heating/ colling cycle? I had this probelm the the intake.

John
 

·
Moderator
Joined
·
8,269 Posts
John.

When you have the heads off check them for flatness as well as the decks of the block. Ford and TFS are often off by enough that it can cause a problem. Being slightly out of flat may be OK for a stock NA motor but not for a blower motor.

Were you watching the A/F ratio during the dyno pull? Or fuel pressure? Going lean on a blower motor under load will kill head gaskets in a real hurry.
 

·
Banned
Joined
·
7,701 Posts
Also, the lower intake could've been overtorqued, thus lifting the heads.

I wouldn't sweat reinstallation of the valve train; all you are doing is dropping in the pushrods and torqueing down the rockers; not a tough task.

For the lower intake, you have to go 'round the whole intake literally 6 or 7 times to get them torqued right.
 

·
FFCobra Fanatic
Joined
·
7,022 Posts
Discussion Starter · #13 ·
THe intake was loose. I retorqued it to spec.
Isn't there a procedure for installing the rockers? I am going to have the heads inspected before I reinstall. What is the best way to check the block? It is staying in the car.

JOhn
 

·
Charter Member
Joined
·
1,558 Posts
John,
I take it DEZ didnt do any real tuning or did he?
 

·
FFCobra Fanatic
Joined
·
7,022 Posts
Discussion Starter · #15 ·
Jim your correct we were just starting.
356 RWHP was the first full pull.
No tuning at all that was the baseline.

John
 

·
Charter Member
Joined
·
832 Posts
Hi John:

Your not alone. Dez started mine last Saturday and there developed a small leak on one Felpro head gasket. I'm having Dez replace the gasket.

Be not dismayed, you'll get it done!!

Did ya see my car down there? Black 95 Mustang w/Procharger?

Jerry
 

·
Senior Charter Member
Joined
·
610 Posts
You need O-ringed head gaskets and good head bolts to play around with more than 8 lbs of boost and a Vortech. Sorry if someone else already said this I didn't read alll posts. A donor motor with no prep work will puke out all kinds of parts with a serious blower on it. The good news is that ...once the block and heads are prepped properly....changing head gaskets will be a thing of the past. I has a stock 351 block O-ringed with TFS heads and I ran a Paxton NOVI at 25 pounds of boost....no problem.
 

·
Registered
Joined
·
450 Posts
I blew a head gasket last summer in my lightning. 351 with a vortech s-trim and about 10 # of boost. took a piston with it. I rebuilt and added Kometic head gaskets and ARP studs. Shuld cure the gasket problem. My 4.6 DOHC cobra motor came factory with the Kometic style gaskets as well. They are full metal layered gaskets. Work very well under pressure and are probably available thru summit though I get them from a local shop.

Im scheduling Dyno time now for the final tune in and to find out what its making, it sure was a change from the stock lightning setup!
 

·
Premium Member
Joined
·
7,237 Posts
Good head gaskets will hold 10# easily. No need to O-ring IMHO if you have a decent tune. I'd rather blow a head gasket than melt a piston any day (which may have happened if you had o-ringed heads)!
 

·
Senior Charter Member
Joined
·
3,085 Posts
Did you get dyno plots with AFR?

Detonation is the typical cause for popping head gaskets. 3 things to watch fuel, timing, inlet temps.

Detonation pressure far exceeds anything your blower can ever add.

I'll agree with Wade, replacing head gaskets is a good thing, considering the other options. The Cometics and other MLS gaskets require a smoother finish on the head and block deck or they like to leak oil.
 
1 - 20 of 44 Posts
Top