Hi guys ,
here is a question.I have a new std scat crank and am looking at a couple of engines, one has been rebuilt 4k miles ago.Assuming the mains are .010 under, could I lap in the crank using time saver --coase and med grit? Would be grateful for answers.
I would suggest that the bearings be scraped close to size and then lapped in with time saver. I have only used timesaver to refit the tapered brass plug in a radiator drain valve. It worked well but it seems to me that 0.010,.005 on a side might be a little much for timesaver. Others with more experience with timesaver might give you a better answer.
Some do not like timesaver some do. Need more information is the crank round? Straight? egg shape? You cant assume much when you are working to 1 thou in straight line across a block If you do not have the proper measuring tools a machine shop can do it.
Hi Paul, its a new scat crank.
If the Babbit is .010 undersized and the crank is standard, I would instal my line boring equipment and bore the bearings to the new size. With .005 of material all around there should be no problem resetting up to line bore and you will then have a like new job
I do like timesaver. Recently cut down the center main on a block the craftsman re poured the rear main cut ten thou large without redoing the middle and front main. Using timesaver fine YELLOW not green it took half an hour using a tool made from a transmission main shaft powered by a drill five seconds forward then five backward. Crank beds perfect now. A Scat crank is expensive. Take 1 to 3 plastigage and see if the clearance falls into that area. If not try 3 to 6
You might just need to remove a few shims If over that new line boring might be in order.
If at all possible I'd find someone with a line bore fixture and get the bearings cut. I too am not a big fan of Timesaver. Sure would be hard on a new crank. Just my 2 cents.
Miss understood your question John. Les has it right Time saver yellow cuts Babbitt, Time saver green cuts steel.
.010" is a lot to take out with timesaver. It can be done by scraping the bearings and then using timesaver, but will take a bunch of time and still will not be a first class job. You can not be sure of the exact alignment of the crank in the block, or the quality of the bearings. Is there a problem with the 4K mile rebuild, or are you just looking for the Scat crank upgrade? There must be someone in SoCal who can either repour and bore the bearings or possibly just bore out the ones you have. I do it here in the Sacramento area, as well as the crankcase straightening. Model T's respond well to low-tech repairs, but if you have purchased a Scat crank, you have the best available. How about the same for the bearings? Just some thoughts.
Les has the right answer. Line boring is the way to go with your new $1500 crank for the best alignment and long service afterwards.
Thanks for all the input guys. Does anyone know a shop or a fellow club member here in So Cal that can ream the bearings ?
John, I don't know if you have made up your mind yet, but I will tell you of one of my Timesaver experiences.
In 2002 I won the Montana 500. One of the drivers complained at teardown about my crankshaft. Even though I passed the inspection, I decided to change my crank just to be above reproach. The original crank was .010 under and the replacement was standard. I did just what you asked about, that is used Timesaver (first coarse then medium then fine) to hog my babbitt from .010 to STD. It didn't take too long to do. To do it, I turned it over with an electric motor. That engine is still going fine today without ever taking shims out of the mains. It subsequently went on to win three more Montana 500 runs and has tens of thousands of miles on it.
Food for thought anyway.
For a shop to do line boring, call Vic Terrell at Antique Engine in Escondido.
I would not recommend scraping or timesaver for main bearings. You are installing a very expensive crankshaft and trying to save a few dollars is "penny wise and dollar foolish" The bearings need to be line bored. First thing of importance is the fit between the timing gears. You need the front main correctly centered to achieve that fit. Secondly, all three bearings must be in perfect alignment so that you don't put a bind on the crankshaft. Thirdly, the third main must have the correct endplay for magneto clearance and also correct fit of the timing gears. I would recommend either line boring the existing bearings, or pouring new babbit and line boring. Note, you might need to pour new anyway if all three don't come up clean when you bore it.
Tom, I agree completely with you. I gave up scraping altogether when I started using timesaver. If you ever tried it you will be sold on it, as I will go so far as to say you can do no damage with it. It works especially well on worn journals and bearings as you can achieve 100% contact if you want. My 24 engine has over 50k on it after an overhaul, not rebuild and folks that have heard it run will tell you it still sounds great. Opinions may vary but the proof is in actually using it. KGB
Interesting post Tom! A friend who drives every day about ten miles each way from home used timesaver after a line bore checked with a two thou shim that would lock the crank up then with a one thou shim that would allow you to turn the crank with effort. Time saver put an even 1 1/2 thou clearance end to end on the main bearings. This was about ten years past and my friend is not easy on a vintage crank.
Can someone please clarify what "timesaver" is???? I was a molder in the Navy and poured lots of Babbitt bearings and never heard of it. Thanks
Lapping paste, powder form and mixed with oil to use, like lapping in valves.
Time saver is a powder usually mixed with oil or grease. Grease would be used on parts oil would be thrown off of. Don't know what it is called but bearing on power plants use something like timesaver and they are run day in and day out. When you look at machined parts on a full screen PC at 200 power its easy to see what timesaver does. Just my opinion!
Ditto what others have said. You need to line bore to within .002", then use Timesaver. It works as advertised. My reason for posting is, Timesaver is an extremely fine powder. Mix it only with good ventilation or outside up-wind (another "don't ask me how I know"). Otherwise, it's definitely the way to go.
Bruce - A special lapping compound. The Yellow (fine) version is intended for lapping babbitt bearings. Lang's and possibly others sell it. See https://www.modeltford.com/item/TIMESAV-Y.aspx
So does this Timesaver doesn't bother the crank journals at all? What about circulating through-out the entire engine and transmission forever? I have built hundreds of different engines and this stuff make me nervous.
It dulls the shiny steel journal somewhat, but doesn't bother it. And no, it won't circulate and grind forever - it only grinds for a little while and more has to be added if the bearing isn't finished. I always clean it up afterwards, but it shouldn't be necessary to clean religiously since it looses its grinding capability when used and will follow the used oil out with the first oil change. I tend to change the oil rather quick after first start of an engine - lots of wear stuff after just one hour of running.
Myself, I never heard of 'time saver'(around here)
until I watched Mike Benders "Model T Tips". Mike
has excellent vidios on utube. I am surprised he
he doesnt get more hits.
I am in the business of rebuilding Model T motors so it is probably in my best best interest if people don't use Timesaver compound, but someone asked so I told of one of my experiences. I would think that a real-world experience should carry some weight, perhaps more than the opinion of people who haven't even used "Timesaver".
There were some perceived problems with "Timesaver" laid out above. I would like to address those.
1. The crank to cam distance would change.
The crank centerline should not change, as the material would be taken equally out of the block and main cap. So if the cam distance was correct before, it should still be after the "Timesaver" treatment. Even if most of the material was taken out of only the block or the cap, the cam to crank distance would only change a few thousandths of an inch.
2. The three mains would be out of alignment.
Assuming the crank that you are using is not bent, the three bearings are going to be in as perfect alignment as possible. When an engine is line bored it is possible for the cutter to move off line slightly for various reasons. Some folks say a reamer that reams all three bearings at once is superior to line boring for the final finish. Using "Timesaver" is effectively reaming all three mains in line.
3. The thrust may be off.
This is true, but the thrust can be adjusted if it is wrong.
Good post Tom, honesty is great!
This is a little off topic but I have wanted to try it and you might have already
A model T transmission is often worn different ways a few thou here and there on triple gears and drum gears making for loud running and a less then good possible mesh.
My intent is to assemble fresh triple gear pins and bushings on a fly wheel along with the drums.with good oil on the bushings and heavy grease where Timesaver could enter bushings.
Set the fly wheel front on the floor using Green timesaver mixed with heavy grease on the gears
Drive the transmission with a 1/2" drill using a cut down front of a drive shaft in to the driven plate.
Used this method on my vintage South Bend lathe gears its much quieter now.
The bearings are .010 under Therefore I don't think you could fit the crankshaft into the block and caps without first scraping the bearings. If you scrape, how would you control the amount being scraped without changing the alignment of things? I don't think scraping and using timesaver would be a good thing when using a new crankshaft. Why risk further damage to either or both the crankshaft and block?
Again, I am not recommending that anyone use "Timesaver" or scrape or anything else. What I am saying is that I have bedded a STD crank into .010 babbitt without scraping (as described above) and it worked fine for me. I have found no evidence in practice that "Timesaver" damages anything.
Lapping babbitt is not a new concept.
is that some product from "down under"?
When I bought a half test kit yellow Timesaver several years ago, the cans were tin and the instruction booklet looked like it was a second printing of a 1940:s first edition - it's been used with success for many years and will not imbed into the metal.
Ok, here's Erik's picture turned right:
Doesn't anyone use blue machinist dye and a bearing scrapper to fit a shaft to Babbitt bearings???
First thing, I do not pour bearings in Model Ts or As but I do re-babbit large tractors and steam engines. In most of these cases, the bearings are poured to the crankshaft. To Bruce's point, I use bluing and hand scrape the bearings to get the proper fit and try to get to about 80% full contact on the surfaces. At this point I use Timesaver and lap the bearing until they are 100%. Below are some short videos of a 5 main bearing crankcase being poured and lapped in. It also shows how easy a 280# crankshaft can turn in a properly aligned and poured crankcase. In this case, removable brass pins were used to align the shaft in the crankcase and support the crank in all 5 bearings. I would never use this system to pour a Model T or A engine. They should be poured to a mold, the babbit peened to the block and then line bored. I have used Timesaver to polish up and get a final 100% surface on old bearings but it is just a final step, it is not a cure to bad or misaligned bearings. Though Herm Kohnke hasn't made any comments on this thread, I'm with him 100% when it come to the correct method of babbiting an automotive engine block. If I were putting a new crank in one of my Ts, I'd go through the extra work/$$ and have the block re-babbited.
Is something going on with my iPad? The pic I posted appears right side up and Roger's is upside down. Did I miss something?
Eric -- Yes, something must be "going on." Your pic appears upside-down on here and Roger's is right.
That's weird. I'll check into it. Something must have happened when I resized it. Thanks for the heads up.
Eriki just locked my screen and rotated mine looked fie ubtil i whent reply then i had turn it back lol
Roger, The videos you posted are a God Send learning how to use a Gene French line bore system. Thanks so much! Paul