Bad rod in a 49 8 engine

SuperDave

I have torn the engine down and found the #5 rod beat out pretty badly. Everything else looks good, mains and rods. The rod journals are 1.925 diameter. the bad one seems to be as much as .015 out of round. Metal has migrated! I would like to find a service in florida that can build up the rod throw. Also will need a newly babbited rod or get this one repoured and bored to fit.. any suggestions?

[Deleted User]

There are machines that can do that in the car. Trouble is finding someone that has one and still knows how to use it. Getting the rod done is probably the easier part ,or fining a good used one,
Roger

SuperDave

The crank will have to be spray welded and turned down. Maybe I can find a new or very good rod and have the journal turned to match.

[Deleted User]

You dont realy know untill you find someone fammiliar with them. seems to me Ive heard the crank can be turned under at least 30 with no problem. But I dont KNOW that, then its just a matter of an oversize rod on that throw,
Roger

SuperDave

Big blob of black RTV was almost completely blocking the pickup tube. note the heat and friction damage to the crank pin.

Jon B

It's not much of a consolation, but at least you know that the problem originated with that blob of RTV and wasn't a fault of bad babbit in that rod (in which case you would then have to worry about the seven remaining rods!).

Geoff

I have seen many engines ruined by over use of RTV. If you are using this stuff, just use it VERY sparingly so it does not squash out in blobs and cause such damage. I much prefer to use a good soft gasket material and just a smear of grease to help it seal better. Again, a blob of grease could do the same damage, so sparingly. I know of one instance where an Essex four motor was assembled with grease around the cam journals. this grease effectively blocked off the oil feed hole, and the bearing seized and melted. I have found grey Loctite 5699 by far the best sealant.

maasfhcenturylinknet

The least expensive way to get you back on the road is to have the journal turned where you are and send the rod to me. I can straighten the rod and pour-bore it for you to the size of the crank. It may clean up at .020 to .030 undersize. I do have a place in Ohio that welds cranks (for repairs and strokers) for me if you wanted to go that route.

Randy Maas 309-267-6158
maasfh@centurylink.net

SuperDave

Randy,
It's taken a while but I did find an old line machine shop in Orlando. They had the jigs to pour Model T Ford rods, but not Hudson... Darn...I took the crank to them and they took the time to check it out for me. Had it magnafluxed, then straightened. Center main was out of center 020". Then magnafluxed again after the straightening process.. Have you ever seen this done? Scares hell outa me!! He got it within .002'. He says if he welds the rod throw, It will warp the crank enough to have to turn the mains. I don't want to have to try and find new mains and probably have it line bored.. so we decided that he would just turn it down until it's round. Looks like it will be only .015-,020 under.. I hope... I will measure the pin diameter and send you the rod to have it poured and reamed. I was hopeing that I could find a rod and have him turn the crank to fit. Didn't work out, so we will go your way.. I'll give you a call tomorow or when I get the crank back. It's 63 miles one way to the shop and nothing but traffic lights for at least 20 miles of it!. I keep telling myself that this is a fun hobby... LOL..

Also of interest, is that the rods all has some shims in them ...except the bad one. I bet it was loose to start with. Also the book says no shims in the mains. mine has a lot of them.. I am going to be really attentive with the fitting..

maasfhcenturylinknet

Seems like it will alway bend a crank when you hammer a rod. You can live with .002 after straighting. Sometimes the crank will break with the process; apparently yours did not. We can fix your rod.

Randy

SuperDave

I drove to Orlando and got the crank back today. The shop, was really nice to deal with. Thier understanding was that i was working with a crank that was made of "unobtanium".. helped. The crank was straightened, checked for cracks by magnafluxing. The rod throw in question ended up only .020 undersize. Much to my relief! So the old rod will be in the mail to Mr. Maas to be resized..
Any hints or suggestions on improvements to the oiling system on these old 8's or help in "fitting' are welcome. ?