adurso19@yahoo.com

Had a shop check the head (with the hardened valve seats) on my 1960 Vette 283 which was blowing white smoke right after rebuild. No. 1 and 7 valve seats are leaking.I can either try Bars leaks to seal it or use the 400 small block heads from the engine I pulled out to put the 283 in. Did some research on bars leaks and one guy said it stopped the leak but he had to replace his radiator, water pump, and heater core and then drain the cooling system to get that "junk" out of his engine. Anybody have good luck with this stuff? Also wonder if the 400's valves will hit the top of the cylinders on the smaller bore of the 283. I know there's a lot of what ifs here. Any advice would be appreciated.

wmf62

I would be pleasantly surprised if Bars Leak would seal against cylinder pressures, but then, if coolant is getting into the cylinder, then it might...

there are also block sealer 'chemicals" you can get....

https://www.bobistheoilguy.com/forum...92&type=thread

Bill

Jeffs82c3

I used it once and I will never use it again... I agree with most of what that guy wrote... Maybe if I was out in the middle of nowhere, I might use it to get home, then flush it out... Good luck..

Boyan

Don't use Bars. Find a very good head machine shop. They can pull the seat, and epoxy it back in with no issues as long as the leak is not huge. They should be able to tell you right away by looking at the seat with head off.

I had this done after I stupidly put in hardened seats.....

Kerrmudgeon

And they may be able to machine down the 400 valves you need to the 283 size to save some money.
Don't be putting that crap in your cooling system.....you'll be sorry. When you fix the head and put in a new sandwich heal gasket your leaking problem should be cured anyway.

427Hotrod

If they've cut the heads so far that there's cracks around the seat....I'd be worried about one falling out.

I'd be looking for new heads.

The 400 heads are going to have some big chambers on them and will kill compression on a 283. They probably have 1.94" valves...so should clear alright....but I'd double check radial clearance on the valve pockets in the pistons.

New heads are what it needs though.

Sealing cracks in combustion chambers with sealers is a last ditch effort to get you home. They work Ok on other areas...but I wouldn't expect it to live in a chamber.

The GM sealant tabs DO work very well though. Same stuff GM puts in the coolant of all new cars and what they used to fix the warranty issue with LS heads seeping coolant from porosity

JIM

R66

First, I hope you had both heads checked??? If so, you only need one head.
I am not a believer in GOO (Bars Leak or other magic epoxies). I have used JB Weld in some coolant leaks with success, but not in the combustion chamber nor heads. GOO deteriorates with heat, cast iron does not. GOO will stick to any metal and plug up the passages as well as the leaks.

A good shop can remove the seats, weld the cast up and thin the seat to reinstall it, but it would cost more than getting a new used head and having it cleaned up. Unless the shop will guarantee the installation of hardened seats - NO WAY. As I said before, I'll send you a set of boat anchors of the cost of shipping.

Never tried the GM sealant tabs, but GM will do a lot of shady things to save the profit margins.

I vote for new heads without hardened seats. You can save your new valves and springs.

Just $.02.

phil2302

I would change the heads. Yes, both of them
How long before the other head has problems ?
$2-300 bucks for good cores and then get them done right.
Example
http://www.ebay.com/itm/CHEVY-283-EN...xYfPOK&vxp=mtr

MikeM

If you look around, you should be able to find replacement 283 heads for your engine, priced by so much a pound. They are not exactly rare or in demand. Just don't mention "Corvette".

The 400 valves will clear the cylinders but the combustion chambers are way too large. You might wind up with about 7.5-1 compression ratio.

adurso19@yahoo.com

Many thanks to all. You cleared up my confusion on what to do. I have so much time and money into the rebuild the only right way to go is a good pair of replacement heads. Thanks again.

GTOguy

Good choice. 427Hotrod said it like it is. You don't want to drop a seat and grenade the motor. BTDT........not fun.