[franky 455]

I have a problem with my 74 Formula with a 455, 30thou bore and TRW Lumpy top pistons, it has around 10 3/4 compression and i have been driving it for the last 15 years, around 20 thousand miles when on the weekend the temperature started to go through the roof while parking, I have a sender in the intake and another in the head, the one in the head went to 230 deg. while the inlet read 150 deg. i thought it might be a jammed thermostat but when I tried to restart it, it locked up. I pulled the plugs and found a few cylinders full of water on both sides. I have taken the heads off and the bores look fine, the head gaskets are not blown and the results from the machine shop say the heads are not cracked. any ideas??

[steve25]

Many questions need to be asked here!

What type of head gaskets where they!

What type of heads are we talking about here, if iron heads then what casting number?

I have used the common Fel Pro 1016 gaskets even on a supercharged motor running 8 to 10 PSI of boost without issue for years!

What cylinders had water in them, two right next to each other?

Why the heck are you running water in the first place?

The gaskets may not look blown inbetween the cylinders, but I can pretty much guarantee you that the high temps are the cause of a head gasket leak, the only question I have is what made for the 230 degree temp that started this whole mess for you?

Iron 4X heads have over the years seemed to be the most prone to cracking if that's what your
running?

I don't know what your expecting for end results by running 10.75 to 1 comp on today's fuel I must admit unless your running Aluminum heads which still can put you on the edge depending on the Cam.

[franky 455]

Common Felpro gaskets, 4X heads, 5,7 and 8 cylinders, I think most people use water, the 4 X heads were crack tested and are ok, I live in Australia and we have 98 octane fuel and it runs well, please remember I have been driving with this combination for the last 15 years and it was first built in 1988.

[Scott Stoneburg]

If the heads are not leaking, that leaves me thinking either head gasket, or a crack in the block. But since its multiple cylinders i am leaning to the head gasket.

[PunchT37]

Head bolts not tight?

[steve25]

well finding water in 5 and 7 sounds like a head gasket, but if your running a dual plane Intake and you have water in number 8 then that's bad as you then have something going on with that head and or gasket also since backed up water from 5 and 7 can not get thru a duel plane Intake and over to number 8.

At this point I would yank off that head also , check the head deck and block for straightness and then find a shop that can pressure test both heads.

If they test out good and all 4 deck surfaces check out no more then .002" out across the lenght and width then I would bolt things back up with new gaskets and even before firing the motor over do a pressure test and see how things pan out.

I would use new head bolts this time around and confirm that they come out thru the head and new gasket no more then 3/4" and I would also confirm that a bolt threads into each hole by hand easily.

Also torque down each bolt in no more then 2 steps , and yank the center two down to 100 lbs, not 95 as this will compensate for the added stretch these 2 bolts see due to the added heat of the two center Exh ports at that location.

Your running just plain water gives you no boil over protection and local hot spots in each head just go over to steam and then no cooling takes place and a over heat cycle starts off and before you know it your reading 230 degree's!

In short you need to run coolant to raise the boiling point atleast somewhat, plus not running antifreeze is a great way to hang up the thermostat valve on its shaft which is what might have happened to you since there's lube .

[franky 455]

Here is some pics

[franky 455]

The heads have been crack tested and are good is all I know right now, what I noticed when unbolting the heads was I only really got that loud crack noise you get when it first releases on the head bolt on the end at No. 8 and with a straight edge across the top of the block it felt a little low in the centre. Possibilities, 1. block not flat 2. stretched head bolts (they have been used a few times) 3.Heads not flat, find out tomorrow. Question for you Steve25, can water in number 3 pot run into 5,7, and 8 through a dual plane manifold?
Cheers.

[steve25]

Franky, coolant getting into any of the cylinders that feed off of a duel plane intakes upper plenum ( cylinders 2,3,5,8) can back flow and get into any of those 4 cylinders, but the most coolant would be found in the cylinder(s) that where the source of the leak, especially once the motor was shut down hot under pressure.

In regards a duel plane intakes lower plenum cylinders 1,4,6 and 7 could show the same results from a leak.

Please note, that once you get this back together and running that once your Exh system gets up to temp your going to likely see steam coming out your tailpipes as that water that got into there boils off, so you may think you have a problem again when you don't!

[franky 455]

Ok heres the kicker, I have a crack between 1 and 3 cylinders its been there for 15 years and yes I need a new block, problem is Pontiac motors were not built in Australia so they are rare, anyway back then a block welder told me not to try and fix it and just pour Chemiweld in it which I did, this has given me many years of driving enjoyment and as I have been restoring a 66 GTO funds are low. I am not looking for a rebuild here so please lets not discuss that unless it is my last resort. Could this crack fill No.3 and then through the intake to 5,7 and 8?

[track73]

Here is an option. I have tig welded a Chevy block with Ni rod (coating removed) so I know it can be done. Then deck it and and sleeve cylinders 1 and 3.

[NeighborsComplaint]

Don't overlook the possibility of head bolts bottoming when the block has been decked and heads milled multiple times. I use hardened, flat-ground washers under the bolt heads. You can usually tell they are bottoming as they don't "creep" up to torque and just kind of top abruptly during the torqueing process. Sometimes they fool you, and you aren't really clamping the heads to seal the head gasket. They can fail right away or when you least expect it.

[franky 455]

Well its pretty much done, that's a 3 thou gap where there shouldn't be one, looks like I'll be searching for a new block and in the meen time i'm going to add Chemiweld into the radiator again which i think is an Australian product, it has kept my car going for the last 15 years. If you are local,( I'm in Sydney ) and are reading this and you have a 455 or even a 400 give me a yell.

[steve25]

I can't tell a thing from your picture!

Where is this .003" gap you speak of ?

If you can get Bars leak products over there I would try there HG-1 product.

[franky 455]

That's a feeler gauge between the sleeve and the block, so the sleeve that was installed has separated from the block. I'll look into the HG-1 from Bars.

[steve25]

So when you lay a head gasket on the deck that gap is exposed beyond the fire ring of the head gasket?

[franky 455]

Exactly, I use Felpro is there any head gaskets that go closer like Chevs do?

[blueghoast]

Fill the crack with JB Weld and then use your liquid stuff.
I've used JB Weld on block that were tortched between cylinders with
good luck and service.

GT.

[franky 455]

Do you think JB will hang in there? I think the water will push it through, anyway this is all a stop gap if it blows it doesnt matter as the block is screwed, its not the numbers matching block so it doesnt matter. I am looking at the Butler 455 stroker short block but I have to wait, we are only getting 72 cents to the US dollar at the moment and shipping isn't cheap. I'll get the heads back for next weekend and start putting it back together with chewing gum if I have to

["QUICK-SILVER"]

How thick is the sleeve? And/or how far away is the gap from the bore?

Earlier pic looked like the fire ring was really close to the bore along the bottom edge.



You would need near brain-surgeon precision, but might want to pack the crack with soft wire and do a final fill with epoxy.

IDK
Clay