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Posted By Discussion Topic: loose valve guides -- page: 1 2     parrish 08-08-2011 @ 8:18 PM reply profile send p.m. Member Posts: 349 Joined: Oct 2009 The valves in my 37 flathead allowed so much wiggle that I investigated and was able to remove the valves REAL fast by just pulling the horseshoe clip out and "boing"...out the top popped the entire valve assembly! Question: does this indicate that the bores have been honed or did the guides actually wear down that much? 37RAGTOPMAN 08-09-2011 @ 5:38 AM reply profile send p.m. Senior Posts: 1958 Joined: Oct 2009 I would try a new guide in the bore, and see if it is sloppy also,[or measure the ones removed and compare to a new ones ] if tight you can replace them.I have not heard of the bore wearing, the guide do not move normally,so I am assuming the guides are replacements made not correctly.lets hope so,,, check into it and let us know, hope this helps 37RAGTOPMAN flatheadfan 08-14-2011 @ 5:15 AM reply profile send p.m. Member Posts: 450 Joined: Oct 2009 Parrish- I wouldn't be surprised if the bores have been honed over the years. If you are worried about leakage around the guides one thing you can do is use later model one-piece valves with solid guides AND have a provision for an oil seal. The seal itself is like an O-ring which fits into a grove in the guide. This seals off an potential leakage. Unfortunately, it also makes valve assemblies more challenging to remove after the engine has some miles on it. Tom Tom supereal 08-14-2011 @ 10:06 AM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 We also machine an extra seal groove on the one piece guides, as some bores are either loose or damaged. It is likely that someone did hone the bores after having a hard time getting the guides out so they could just drop them in at reassembly. parrish 08-17-2011 @ 7:47 AM reply profile send p.m. Member Posts: 349 Joined: Oct 2009 thanks...I ordered a solid valve guide from Kyle over at C&G as a test and will give it a try shortly. I also ordered the seals which are packaged in a set of 8, so I assume the exhaust guides get too hot to use a seal? parrish 08-17-2011 @ 8:00 AM reply profile send p.m. Member Posts: 349 Joined: Oct 2009 After re-reading the replies, I'm questioning if the new solid guides money would be well spent. The mushroom valves would need to be replaced with the straight stem as well. With the kind of looseness I found on the split guides, wouldn't there be severe oil blow by? (This engine has not been fired up in a long time and is still in the discovery phase) supereal 08-17-2011 @ 8:33 AM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 We use solid guides and stainless valves and, of course, adjustable lifters. We assume that, since a real rebuild isn't cheap, using the best components is required. One piece guides were used on the last of the flatheads because of better stem sealing and longer life. You can still grind the stems for clearance, but adjustable lifters allow resetting if any valves develop clatter later. We also install new valve seats to allow better valve sealing. Many old engines have insufficient seats. They not only leak, they allow valve burning because there is limited heat transfer to the block as the valve head closes. There are no shortcuts to a quality rebuild. parrish 08-20-2011 @ 7:39 AM reply profile send p.m. Member Posts: 349 Joined: Oct 2009 I received the test one piece valve guide and seal from C&G and it is a VERY tight fit in the bore...and this is after the old 2 piece literally popped out of the bore! Was the old 2 piece THAT worn? Or are the one piece guides different? The valve guide is so tight that trying to get the o-ring type seal on at the same time is going to be problematic... TomO 08-20-2011 @ 7:59 AM reply profile send p.m. Senior Posts: 7252 Joined: Oct 2009 The one piece guides have the same outside diameter as the split guides. The guide should not move in the bore, so if the split guide was the correct diameter, there would be no wear on the outer diameter. Your guides must have been undersized. Use a micrometer to measure the guides and the bores. I don't have the exact dimensions, but more than .002 would be too loose IMHO. The easiest solution is to order new split guides, have the valves and seats ground and re-install the valves. Because the loose guides allowed the valve assembly to wobble, you need to ensure that the valves and seats will match up with the new guides. If you want better oil control, go with the straight valves and 1 piece guides. Have the machinist check the valve stems and guide for correct clearance. If there is not enough clearance you will have problems with sticky valves. Tom supereal 08-20-2011 @ 8:38 AM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 To get the one piece guides into the bore, first be sure the bore is absolutely clean and free of carbon deposits. Lubricate the exterior of the guide and the seal. We use Vaseline for that purpose. Don't enlarge the bores. The tighter the guides fit, the better.

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