The Stovebolt Site Forums The Shop Area Engine Shop New engine rebuild tips for 235 (1959 3100)

Hello guys, I dropped my 235mfrom my 1959 3100 off at the engine shop for a full rebuild of the long block. He has been in business for 40 years. Is there anything special that i should know to prompt him or query regarding tips or tricks regarding this engine while there is still time. It has the 848 heads so I believe the oiling issue is exempt. So if there's anything you feel I should know, please advise and I'll let him know. Thanks in advance.

Make certain to take him a copy of the GM specs and don't let him deviate from those. Especially: piston to cylinder clearance. Take him the pistons marked 1 through 6 and have him match each piston to each cylinder so there won't be any questions. Check ring gap also. I've seen some rebuilt engines that were bored & honed so loosely and poorly they were going to run like they had 20~30,000 miles on them the first moment they started. Get the camshaft checked and reground by a specialist if needed (Schneider Cams in San Diego for example). Get new valve lifters...solid lifters. The rear crankshaft sealing surface is really important to making sure you don't have a leak there. Have him install a Speedi-Sleeve back there if needed. Use the rubber rear main seal. When the crankshaft is re-ground make sure the GM specs are met...try for .001" crank journal to bearing clearance. On the camshaft gear, try also for .001" clearance between the thrust plate and camshaft. Get the top of the block and head checked for flatness and re-surfaced if needed. He should know all of this but some machinists may not think of everything. If you're having the head re-done, use bronze valve guide inserts and check the old valves carefully. If the head or block must be resurfaced very much be sure to recess the valves in their seats, too.

There is a way to machine the back of the engine block to take a full circle lip seal that works much better than the 2 piece seal. Most auto machine shops have the equipment to do that job, if they know how to set things up. I'd be glad to consult with your machinist if he would want to discuss the procedure. The seal I use is a National #417210- - - -3 7/8" inside diameter and 4 3/4" OD. There are usually several available on Ebay at pretty reasonable prices. Good luck!
Jerry

3100Apache ...

As the owner/publisher/editor/chief bottle washer of this web site (when Peggy isn't online ... ), let me put the full endorsement of Stovebolt.com behind Hotrod Lincoln's offer. Do not hesitate to take him up on his offer, or any other he might makes. FWIW, I currently run a 261 engine in my truck that he personally rebuilt (teaching a bunch of us in the process). And he currently has the rotating components of my '27 171 engine for some very sophisticated upgrades.

Jon G has my full endorsement, as well. Two great, knowledgeable guys!

Some others of equal authority will no doubt add to this as well.

Thanks for checking in and asking questions -- it's what we're here for. We've already learned the hard way so we can flatten your learning curve and help you learn the easy way!


John

Thank you very much gentleman. I will speak to the rebuilder. Appreciate the info

IIf you recess the seats, slightly relieve the head surface around each seat down to the new seat depth.
This unmasks the seat so that flow begins immediately the valve cracks open. It can be machined at a 15° angle for the intakes and 30° for the exhaust.