Running 10 psi on my paxton.
I dont know if its the compression being too high or what. I will drive the car for a couple blocks then nail the gas and pop, coolant out of the radiator.
Im stumped.
The heads were just shaved for flatness. I checked the block with a square and a feeling gauge.
any ideas from the crowd?
What gaskets are you using? I like standard Felpros. I use them in nitrous and turbo apps. Are you sure it isn't just a bad rad cap as well? Dirt and crap on them can cause a spattering overflow that can look like blown gaskets.
First thing, check your tune! Maybe take it to the dyno without the charger and with the charger. I was told to put a light coat of oil on the head gasket by an old school racer. He said that if you coat the gasket with a little oil, it will get hot and suck down to the block and head creating a super tight seal. I don't do this becasue I use the flepro 1010 gasket for my car..chevy. The 1010's say they need to be put on dry, otherwise I would have tried it.
Brian I have run 14psi all day long and never lifted a head. Like in the earlier topics detonation will get you each time. You need to keep your timing under 20 total till you hook up your A/F meter. If your heads have been milled are you sure the intake is covering the water ports completely and your not blowing the intake gasket or lifting the heads with the intake bolts.
It has to be detonation then.
I have my timing set at 10 with the spout out. THen I plug the spout back in.
I pull out around 1-2 degree's of timing with every pound of boost with my BTM.
Before I upped my boost from 8psi to 10-12 psi I was running 9 on my a/f meter at the richest. I dont know what difference the extra psi would cause.
I really hate to take my car to someone and pay 400 bucks just to get a crappy tune and more blown head gaskets. If a tune is what I need, then thats what I'll have to do, I will just have to wait until next year it seems.
I tried using the felpro's with the metal fire ring and i also tried the nice graphite ford gaskets.
I replaced my radiator cap twice now. The last time I went and got a motorsport radiator cap.
Time for some guesswork.
1) make sure your # 6 & 7 plug wires are well separated, these two are within 45 degrees in the 5.0/351W firing order, if they are touching anywhere the spark can and (Murphy's Law) will jump across the wires for an instant +45 degrees ignition advance. Gapping down the plugs more than you think is necessary can help with this.
2) Check the voltage at your fuel pump, make sure you are getting the juice there needed for the pump to flow at rated capacity. (you do have enough pump right?)
3) It sounds like you know what you are doing with the head bolts & gaskets, but you might be missing something obvious. What brand bolts are you using? What lube or sealer, on which bolts? What kind of torque wrench, was it calibrated recently? Are you retorquing? Before or after intake install? Beofre or after warmup run?
There's a million different little details like this that can go wrong when subjecting an engine to high boost, hard to guess what it could be.
HTH
Chris
All help is appreciated.Originally Posted by fanglemeister
1. I gapped my plugs from the stock gap down to .32. I need to check and see what plug I have. They are NGK's that came on the car, I havent checked the model number.
2. I have a 255 in tank pump running 36lb injectors with a 6:1 fmu.
3. I am using arp head studs. I chased all the bolt holes with a tap. THe bottom water jacket studs i used silicone on the bottom and rear gear oil on the tops. On the top head studs I used rear gear oil on the tops and bottoms of the stud. I am using a snap-on torque wrench. Its accurate. The last time I did my head gaskets I let the car run without the supercharger for 1 hour. I shut it off, let it cool down over night and re torque the bolts the next day over 24 hours later. I am using 85 ft/lbs.
I torque the heads without the lower intake when I first put them on. After the warm up, the heads get retorque with the lower intake attached to them.
Let me know if I left out anything. I cant figure this out on my own it seems.
The old lube up your head gaskets trick. Isn't that about like checking for headlamp fluid. I maticulously make sure my head and deck surface is clean with brake cleaner before installing any gasket.
Any of the tricks for lubing up head gaskets or spraying on any sealer to them is for a cold start up. That is when the head gaskets have the hardest time from keeping coolant from seeping. That stuff has nothing to do with sealing the combustion chamber or being resistant to blowing a head gasket.
Chris
9.05@152 with a T-Trim on BFG Drag Radials
NMCA SR6381
You could also be having the famous BTM is not worth CRAP problem. You can use a hand vacuum/pressure pump and while having the car running and using a timing light watch and see if the timing retards when you start pumping pressure with the hand pump on the BTM and then recalibrate the BTM to match. If the BTM is not working 26 total degrees and 8-10psi you could be asking for trouble. The main thing is get it back together and keep the belt off the supercharger and make sure it is not something that is not supercharger related. Do you use sealant around the water ports on the intake gasket? What did your last gaskets look like. Do you have a digital camera to take pictures and did you keep the old gaskets to compare with these when you take them off.
We calibrated the BTM per the instructions on the corral using a timing light so i think im cool there.
I have a thin layer of silicone on both sides of the lower intake gaskets around the water jackets.
When my last head gaskets blew, the fire rings were in perfect shape. The gasket blew in three cylinders. In every cylinder it blew in the same spot. At the top of the cylinder towards the lowering intake, the gasket material was ate away, it looked like a tree in a way. it started with a 1 mm gap by the fire ring and branched out from there towards the top of the head. The last time it blew coolant into the lifter valley.
After i blew it up this time i still have not taken it apart yet. today i did a compression test and pretty much confirmed cylinder number 7 blew the headgasket. it always blows in that cylinder it seems. but the heads are straight and i triple checked that cylinder for flatness last time just to be sure.
i do have a digital camera and will take pictures of the gaskets as i remove them tomorrow. i did not save my old gaskets.
Here is a head gasket post off the oldsmobile board I normally read
Quote Mr. Olds
"They are available in .027 .030 .036 .040 .045 . also many bore sizes from 4.400 down as small as you need.
These are the multi layer steel that are being used by most turbo engine builders and such well known names as Warren Johnson. They are also reuseable and this price is only about 15.00 more than Felpro 1155's. "
Quote TQ
"Just an additional note on Cometic gaskets....I have used these extensively in Ford small block engines (10 head bolts also), and have had tremendous success with them. On an aluminum block/aluminum head engine with no reciever grooves or o-rings, they have held up to 42-44 psi boost pressures for 150 runs (so far!) with no failures. I have heard rumors that these gaskets may be reusable, but I probably wouldn't try it myself (I may be way off base on this point). Another big hooray about these gaskets is that they don't leak water at all and require no sealer of any kind when installing them. Truly the "cat's meow"!!
Travis"
Quote Mr. Olds
"TQ
They are reusable as Warren Johnson did 7 cylinder head changes in one day on the Dyno with the same gaskets every time . As long as the Viton coating is good and between the cylinders is at least .015 thicker than the compressed thickness they are good to go.
TERRY"
These gaskets have come well recommended to us at the board. Can't use them with orings or reciever grooves. Hold up to some good boost. Pricey, but you may check out and see if they have an application for you.
Brian
Brian, have you ever verified TDC on your balancer with a piston stop? Maybe 10* is 20*, or 30* or ect....worthing checking out.
89 Coupe with parts stacked inside of it and about 30#'s of dust on it with no end in sight. :weird:
Although I am collecting parts for a 12.5:1 393 :D
Its not 100% verified but its very close.
We checked tdc many times in relation to the crank. just not with a piston stop.
A better head gasket is not the solution in this case, instead of replacing head gaskets Brian would be replacing pistons or a cracked head. I have seen people with 25psi on a 5.0 block and never seen one lift a head yet with ARP Head Studs so to me a good tune and cheap gaskets saves a lot of money. My $10 gaskets are like a Blow-Off valve made for heads, I will no when I pushed to hard because the head gasket is going to go first. My .02 opinion., Give or Take .01
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