Drilled Crank Thoughts...
01-10-2008, 07:53 AM
#256
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I haven't built an engine in years, but it only takes one chip of steel, or one piece of crud to create a disaster like the one Stan has.
Stan, I see that the cost of the crank is an issue for you, but the question isn't whether you can afford to replace the crank , the issue is whether you can afford NOT to replace the crank. And you need to have all the rods reconditioned or at least checked out again, and then you need to clean, clean, clean. You should go over the block for straightness as well, all the usual stuff.
If you cross drill your new crank, I would consider sending it to someone else. Don't ask me why, I don't know. And even if I trust the machinist, I still plastigage the bearings.
Bottom line is that you just need to get back up on the horse. And consider picking up a solid short block that you can refresh and use as a spare. There is some peace of mind to having a whole new matched assembly with no question marks around it. Drop the sucker in,and go racing while you build your magic engine. You could probably pick up a beater cheap, and part out what you don't want to recoup your outlay.
Also consider that MK may be right about the friggin Amsoil thing.
Stan, I see that the cost of the crank is an issue for you, but the question isn't whether you can afford to replace the crank , the issue is whether you can afford NOT to replace the crank. And you need to have all the rods reconditioned or at least checked out again, and then you need to clean, clean, clean. You should go over the block for straightness as well, all the usual stuff.
If you cross drill your new crank, I would consider sending it to someone else. Don't ask me why, I don't know. And even if I trust the machinist, I still plastigage the bearings.
Bottom line is that you just need to get back up on the horse. And consider picking up a solid short block that you can refresh and use as a spare. There is some peace of mind to having a whole new matched assembly with no question marks around it. Drop the sucker in,and go racing while you build your magic engine. You could probably pick up a beater cheap, and part out what you don't want to recoup your outlay.
Also consider that MK may be right about the friggin Amsoil thing.
I use Amsoil, so MK ain't right there.
Maybe there is something is this 20 page plus thread where it says the cost of a crank is an issue to me, but I doubt it. I have two good 5L cranks here now that could be drilled. I also acquired a stroker crank over a year ago, and it makes getting a 5L crank drilled look cheap...
With regard to drilling, I have no idea who Devek had do the drilling, but clearly Taylor machine is the shop of choice now. I had a crank drilled there, but it went with some other parts I sold when I committed myself to the stroker project build.
Anyone want a good 5L crank to get drilled, please let me know. I would like to get another stroker crank to build a motor for the GT too
01-10-2008, 07:54 AM
#257
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mtcarrera posted that he broke two 4.7 motors.
In a no doubt vain attempt to get back to the topic; I assume these 2 motors did not have drilled cranks? It was not specifically stated in the post if they did or did not.
One had Amsoil which I thought solved everything?
Marton
In a no doubt vain attempt to get back to the topic; I assume these 2 motors did not have drilled cranks? It was not specifically stated in the post if they did or did not.
One had Amsoil which I thought solved everything?
Marton
01-10-2008, 08:00 AM
#258
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mtcarrera posted that he broke two 4.7 motors.
In a no doubt vain attempt to get back to the topic; I assume these 2 motors did not have drilled cranks? It was not specifically stated in the post if they did or did not.
One had Amsoil which I thought solved everything?
Marton
In a no doubt vain attempt to get back to the topic; I assume these 2 motors did not have drilled cranks? It was not specifically stated in the post if they did or did not.
One had Amsoil which I thought solved everything?
Marton
If I recall correctly, is has been speculated elsewhere that the 2/6 failure was uncommon (perhaps unheard of) on the pre 5L motors, so this could be a rarity too.
01-10-2008, 10:13 AM
#259
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Don't go to a machine shop and ask them to cross drill it, that isn't what you want.
As I recall all 928 cranks are cross drilled anyways.
What you would want is to have the "drilled like a chevy" mod which changes the internal oil flow. Taylor Machine of CA is the best known shop for doing this.
Failures are more commonly found in 5L blocks. I ran my 4.7L on the track for 2+ years without issue using the stock crank. When it was removed the rod bearings were still in good shape. So, I don't know that you need to do this with a 4.5L, but Dave did mention he had a failure with a 4.7L, so....
As I recall all 928 cranks are cross drilled anyways.
What you would want is to have the "drilled like a chevy" mod which changes the internal oil flow. Taylor Machine of CA is the best known shop for doing this.
Failures are more commonly found in 5L blocks. I ran my 4.7L on the track for 2+ years without issue using the stock crank. When it was removed the rod bearings were still in good shape. So, I don't know that you need to do this with a 4.5L, but Dave did mention he had a failure with a 4.7L, so....
01-10-2008, 11:15 AM
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01-10-2008, 11:30 AM
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01-10-2008, 11:37 AM
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Dave has had two frustrating failures. I do not know if the same engine is involved and more importantly, the same rod(s). You both have embarked on a solution costing many thousands of dollars, namely a dry sumped engine. If this is the same rod and crank being put into that setup my prediction is that it will fail in about the same period of time and rpm restrictions as the two previous failures. That would be tragic.
Kind regards,
Kevin
Kind regards,
Kevin
Of course there is also the probable advantage of extra hp from a drysump as well, so there is an additional benefit there as well.
I consider the drysump to be a likely one time expense and unfortunately when considering the ridiculous (to me) costs of the overall car build, it really isn't that much. I try not to focus too much on what I spend, as I know it just plain foolish.
01-10-2008, 12:56 PM
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HTH,
Alex
01-10-2008, 01:03 PM
#264
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I lost 2-6 bearings on a 4.5 in a short time on big Willow many years ago. The big difference in cranks was the main bearing thrust surfaces were increased in mid year 1984 so different bearings. I think all the stroker cranks Moldex or Scatt (DEvek) have been drilled like a Chevy with the main bearing (thrust bearing) grooved to provide an additional source of oil path to 2-6 . All the 95.5 mm stroker cranks use chevy rod bearings and custom "chevy" rods. Only one of Mark's early strokers 94 mm or so used a Porsche rod bearing but aftermarket rods.
01-10-2008, 01:08 PM
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Paul Anderson solved the problem last season by installing a IJ full crank scraper set-up...
01-10-2008, 01:26 PM
#266
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So that tells me one could save some coin by using an early crank then. When was the last time a track or race car spun a thrust bearing or any main bearing?
01-10-2008, 01:33 PM
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I think Kibort when they built the hybrid 5 liter for his friend's early race car used the early crank in a late block...
01-10-2008, 01:35 PM
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01-10-2008, 01:41 PM
#269
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For the record, "drilled like a Chevy" is a misnomer for what Jay at Taylor Engine does. Dennis K has recently dociumented the Taylor Engine drill patterns.
https://rennlist.com/forums/showpost...9&postcount=47
https://rennlist.com/forums/showpost...9&postcount=47
01-10-2008, 02:08 PM
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"drilled like a Chevy" is a misnomer
Why do you say that?
It is drilled "like" a Chevy. Just not 100% since your starting off with a crank that already has oil passages. It is very close and the same concept
That term is used so others don't confuse it with "cross drilling?