Here's a pic of an original steel shim head gasket. Note that the gasket blocks off those holes you mentioned. Besides, only 3 of those holes have corresponding holes in the head. The Fel Pro gasket has the same hole layout...so you will be fine!:TU:
what happens if you did not apply sealer to the headgaskets? i thought that was just to hold it in place... i'm using the felpro's come to think of it i've never used any sort of sealent even at the dealer level.. never had any problem
:error: I count 7. Which ones are blocked off/not used in the head? The questions remains- why would we intentionaly want to block off ANY water passage holes? Erik
No error. 'cmh nailhead' asked about 7 specific holes that are blocked by the new head gasket....my answer was that only 3 (of those 7) have corresponding holes in the head. There are of course, other holes that water DO flow thru.:grin: I would guess that the 7 blocked holes were not designed to have coolant flow thru them, but are there to remove the casting sand from internal passages during manufacture.
Walt Thanks a bunch for the help and the picture! It just seemed odd that all those passages were blocked off but it sounds like that's the way Buick set it up. By the way, my 66 GS is astro blue also. Take care. Rob
Walt- I didn't mean your post was incorrect. Blanking water passages off with a gasket still seems wrong to me too. (Inquiring minds just can't live with the explanation - "just because") ok... so I will bite: Hypoteticaly, What would the effect be of opening those 3 passages that do have a corresponding passage to the head? 1. More flow= cooler engine temperatures :TU: or 2. More flow= could also mean hotter temps (less dwell time). Just as the same effect with the 3/5 vane water pumps have with or without A/C. or 3. Less flow = flow is diverted rather than complete circulation through the entire head. (That's why I asked which ones- I added numbers to the picture) There have been a lot of discussions around here on the boards about overheating problems... and no, I'm not going to do "holey head gasket" testing on the dyno. The dyno has it's own water pump/circulation/heat exchanger system, so testing there would not be a good test. The best testing would be using the vehicle's water pump and cooling system. Oh and thanks fo posting the pic! Erik
I just checked my original 44 year old head gaskets compared with the HG's in my gasket kit from TA performance... I agree.. they ARE the same.. I am contemplating doing the "holey gasket" test on my car when I finally put it back together... Though, I didn't have a temp gage before, and am going to go with a dual-row double-pass griffin aluminum radiator when it's back together... so there won't be much "before and after" proof. wes
LOL! ...that's going to cost us extra, huh?:grin: According to the Buick service manual, coolant enters the front of the block, and leaves at the front of each head. I would guess that extra coolant holes in the middle of the block/head would reduce coolant flow to the rear cylinders. That 401 I pictured did have holes rusted thru the steel head gasket. So in effect it did have the extra coolant holes! The car didn't have any obvious cooling problems. I've had my 425 together since 1979 and haven't had any problems with the FelPro head gaskets. Head and block surfaces weren't machined and no sealants were used.:TU:
Let me jump in here, back in the ''good old days'' ????? we would use the good old permatex aviation gasket sealer, whitch we called ''tobbaccer spit'' because that is what it looks like. It worked good, could be thinned with lac. thinner, and is still on the mkt. It never completely hardens, so the head can be removed later easily. You just brush it on both sides and then put it together. [it is real hard to put it on after you put it together] he he. If we had a engine that was popping head gaskets and used the thin steel gaskets, we would spray both sides with alluminum spray paint and then put it together with the paint still wet. If you use this method the head will be difficult to remove later. i have seen a lot of gasket ''poppers'' cured this way. The best way to prevent problems whin using the steel shim gaskets is to use the ''old'' proceedure for installing them. Clean the head and block, coat the new gasket with sealer, torque. Upon start up, let the engine warm up for at least 20 min. , shut it down and retorque. Then after about 500 mi. of use retorque. This used to be standard proceedure and we very seldom had a blown head gasket later.
My 1/2 full can of Permatex 'Aviation' sealer is 40 years old-still acts/looks/smells the same as when new. I don't use it much anymore, and never did use it for headgaskets. It's good stuff, but other products are out there now, too. I don't use sealers for head gaskets, but make sure all is very clean and I have a certain flat file that I like to use for prep. Jake-you are dealing with alot of alum heads and iron blocks these days where expansion/contraction rates are different. This puts the head gasket into a different sealing situation than our iron/iron nails see. Things clear as mud yet?
Jake, GM says if it is a steel shim style gasket, use of a spray type Permatex is recommended. (brush type sealer would be OK) If they are coated gaskets, absolutely no additional sealer should be used, especially on dissimilar metal engines. That all being said, the gaskets on a Nailhead should seal up nicely if everything is clean and flat. You can bench test the block's coolant system with a pressure tester and some plugs, if it holds about 15 to 17 PSI, your head gaskets should be sealed ok. You can also bench test the oiling system too, using a drill and a modified distributor shaft and housing. Dan Lapham has also fired up Nailheads on an engine stand to check them out before installing them, makes any rework much easier than after it has been installed! Just some ideas! Tim:Comp:
thanks tim. i'll have to have snap on fix my coolant tester. as for starting it on the stand... don't think i'll chance that thing falling over.... the dyna was heavy enough to pick back up after a wheel on the stand fell off.... that'll be the last time i borrow a stand. btw i moved again now i'm at denny heckers toyota.... i just never satisfied... :grin: toyotas arn't much different than gm's:laugh:
Jake, With the dynaflow, you would have to bolt the engine and transmission together to start it anyway, ring gear is on the torque converter!ou: Dan uses a stand and then lifts the engine with a cherry picker, works out pretty good. I'm sure that Toyota's break often enough to keep you busy! They are finding out what GM knew for a long time, when you build millions of cars every year, something will break! LOL!! Tim
