A very happy new year to you all. I need to take off the heads on my 455. It needs new exhaust manifold gaskets and a good clean up, replace the valve stem seals etc. The engine is still in place. (unfortunately, the bolt heads on the manifolds are so corroded I can't do the job without taking the cylinder heads off) Are there any top tips or minor modificatons worth doing while I've got it in bits ? More importantly, are there any 'DO NOT DO THAT, WHATEVER YOU DO?' tips, any help is much appreciated. Cheers for now. Dave.
Check the valve guides for wear, mill the heads flat on the deck and exhaust manifold side, and GOOD LUCK with getting those exhaust manifold bolts out!:ball:
Sometimes in the past I was lucky getting rusted bolts out that the head is rusted smaller by hammering a metric impact socket onto the bolt head. If the threads are siezed in the heads, that's a little tougher. Sometimes if you carefully hammer on the head of the bolt using a large punch it will help free them up first without heating them. Don't hit them too hard though. This method has worked well for me once or twice.
Buick didn't use valve seals on the exhaust valve, just the intake. And my understanding is that the intake seals are just tiny rubber "O" rings on the valve stem. If you are burning oil I'd look hard at the valve guides.
I.m not burning oil at the moment, thankfully,but I fugured that I've got them in the gasket kit, the heads are coming off, so why not fit 'em ? Thanx guys. PS what's a nailhead ????
Nailhead refers to the early v-8 buick engines built 1966 and before. They are called that because the heads on the exhaust valves are small and resemble nails. These started out at 322 ci and later became 364, then after that became 401, and in '63 it was bored larger and became 425 ci. The 425 came from the factory with dual 4 barrels on some models.:Brow: That is what lives under my hood.:grin:
Thanx for that brief but informative piece of data, they say ya learn something new every day and I guess that's my gem for the 23 of Jan. Cheers, Dave
Good news, I managed to get the manifolds off today. The only casualty were 3 sheared bolts, not bad considering they've probably never been off in 31 years!!!!! I've drilled em out and re-tapped the holes. I found the drivers side manifold has a small crack in it, anybody had any success in welding them ? I've got a good arc welding rig and acces to cast welding rods, worth a try I reckon. Everything else inside is looking good, just a clean up and re-assemble and 'Elwood' will be breathing again. Wrap up warm out there, we've just heard it's heading our way in the coming week. Can't wait!
Hey Dave, While you have the heads off and the budget allows, why not just throw some stainless stage 1 valves and some mild port work into them. As stated in an earlier post get the exhaust flanges machined smooth to ensure a good seal. Also do the same to the exhaust manifold escpecially if you weld on them.:TU:
welding manafold (s) Dave, Since you are in England. I think your best option is to weld on it Just do it correctly or you will have to take it off again. Basically you will need to heat it up before you can weld on it. Had one of my heads welded by a very good mechine shop here and it has held up great.
