More split head six questions

[Guest Paul Manuel]

I am building my first split head engine ( 1928/29 186 ) and have been crusing these forums for information. Questions like, how much slack is acceptable in a timing chain? Is a new chain available? What is the proper grade bolt to replace head bolts? Whats the deal with the oil pump, the center section seams to crack around the bolt area on the outside thank goodness, what is acceptable clearance inside the housing around the gears? Is there repair parts for the distributor ( cam lobes )? How available are Marvel Model A carbs and parts?

[Guest]

I have overhauled my engine twice. At 120,000 and at 499,000 miles. The slack in my timing chain had not changed between jobs (3/16"). My gears were badly scored with lots of end play but still gave 15lbs at an idle and 40lbs at 55mph. I put in new gears and dressed the body down to .020" end play. Are you sure you need new lobes??? My points didn't open the same amount all the time and I discovered that I had to put a bushing in the housing, because the shaft was wobbling. There is a set of gears on ebay now.1926 1927 1928 1929 1930 Pontiac 6 1930 Oakland 8 Oil Pump Gear Set NORS # 271790688247

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[Guest Paul Manuel]

Thanks Tinindian for the information. I wish I only had 3/16" play, my chain is so loose it can slap the oil spray nozzle. I was able to find a new one at CPR. With a complete overhaul new pistons, new babbit, new valves and guides etc. I will go ahead and put a new chain. I doubt if I will ever put the miles you do but I want it as good as I can get it to start with. The lobes on my distributor are wiped out. Mine is in a 1928 GMC and the carb rock guard I have for it is the one I showed the other fellow in his post. Maybe that's the difference, Pontiac vrs. GMC, I don't know and info is hard to come by. Thanks again for sharring your knowledge and advice.

[Guest]

If it is the split head engine it is the same. If you go to ebay and check out 1929 Pontiac you will find a guy called choppshopp. Contact him he has been selling a lot of Pontiac parts over the years. Any Pontiac distributor 26-31 or 32 6 cyl should work.