Crank scrapers. Who uses them?
#1
Race Car
Thread Starter
Crank scrapers. Who uses them?
I'm thinking of installing a crank scraper on the 1988 2.5
Who's using these?
Is it worth the extra money for the teflon one?
Any problems or suggestions for install?
Thanks.
Who's using these?
Is it worth the extra money for the teflon one?
Any problems or suggestions for install?
Thanks.
#3
Rennlist Member
I think one purpose of a crank scraper is to remove oil from the rotating mass of the crankshaft and thus obtain very small increases in horsepower and/or throttle response. In the case of a 944, there would probably not be any noticeable increase, except for the placebo effect.
Now if they serve to mitigate the "egg beater" effect of the crank introducing entrained air into the oil, then based on my article at the link below, you may be helping to save a rod bearing by adding a crank scraper. Unfortunately a difficult thing to prove. I've been running without one for years with no rod bearing problems, knock on wood.
I ran into a BMW guy at a DE who swore that a crank scraper resolved all his bearing failure problems but then he as a BMW guy so go figure
https://newhillgarage.com/2013/06/25...tem-explained/
Now if they serve to mitigate the "egg beater" effect of the crank introducing entrained air into the oil, then based on my article at the link below, you may be helping to save a rod bearing by adding a crank scraper. Unfortunately a difficult thing to prove. I've been running without one for years with no rod bearing problems, knock on wood.
I ran into a BMW guy at a DE who swore that a crank scraper resolved all his bearing failure problems but then he as a BMW guy so go figure
https://newhillgarage.com/2013/06/25...tem-explained/
#4
Addict
Rennlist Member
Rennlist Member
Not sure if this is turbo only, but 88+ pans already have integrated scraper. If you have it, I think there is no point in adding another. If not than it might help.
#5
Race Car
Thread Starter
My 88 has the level sender so I guess it must have a scraper. Until viewing your photo I could not tell the difference between new & late pans, but the angle you've taken nailed it! (been looking everywhere except where I should be).
#7
Rennlist Member
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#8
Drifting
Noah,
Look up Ishihara Johnson crank scrapers on their interweb page , i have one of their metal units on my race car engine and it seems to do the job ... very tight tolerance with the crank ! From what i understand , it helps to keep the oil from " frothing " in the oil pan therefore reducing the risk of oil pump starvation ...
You should baffle your oil pan as well with the Lindsey unit if you're that concerned about the engine.
Email me if you need some pictures, i might have saved some when i did the rod bearings last season !
Look up Ishihara Johnson crank scrapers on their interweb page , i have one of their metal units on my race car engine and it seems to do the job ... very tight tolerance with the crank ! From what i understand , it helps to keep the oil from " frothing " in the oil pan therefore reducing the risk of oil pump starvation ...
You should baffle your oil pan as well with the Lindsey unit if you're that concerned about the engine.
Email me if you need some pictures, i might have saved some when i did the rod bearings last season !
#9
Rennlist Member
Thanks to Voith my memory has been jogged. I did "upgrade" to a later oil pan, as shown in his picture, for my track car. Again, I caution that it is very difficult to identify cause and effect with regard to bearing issues. All I will say is a crank scraper can't hurt.
Also for what it's worth, I do not run a pan baffle (the swinging trap door thing). And I have put this car through a long weekend of abuse at the NCCAR test track, with g loads above 1g, without incident. Your results may vary!
If you are inclined, Google the NCCAR track map and you will see that it represents a pretty robust workout to the oiling system. The only thing missing was elevation change.
https://newhillgarage.com/2016/04/29...ack-car-nccar/
Thanks
If you are referring to the Michael Mount bearing mod, as a mechanical engineer, it appeals to me. I would strongly consider that in any of my future engine builds destined for track use.
Also for what it's worth, I do not run a pan baffle (the swinging trap door thing). And I have put this car through a long weekend of abuse at the NCCAR test track, with g loads above 1g, without incident. Your results may vary!
If you are inclined, Google the NCCAR track map and you will see that it represents a pretty robust workout to the oiling system. The only thing missing was elevation change.
https://newhillgarage.com/2016/04/29...ack-car-nccar/
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GREAT WRITE UP HARVEY!
If you are referring to the Michael Mount bearing mod, as a mechanical engineer, it appeals to me. I would strongly consider that in any of my future engine builds destined for track use.
#10
Three Wheelin'
I have talked at length with some 44 engine gurus and all I can say is take a look the Lindsey article on their website about "cylinder pumping", It makes sense to me. Any good machine shop can do it. At the end of the article it makes a good point...... When is the last time you have heard of a 968 rod bearing failure?
#12
Addict
Rennlist Member
Rennlist Member
Its not coating, teflon scraper is made of steel and another thick layer of teflon.
#14
Race Car
Thread Starter
Hope not... but that;s better then steel scraper getting in your lube system.
----
So installation is: loosely bolt on, then rotate crank as you bring scraper as close as possible to crank, possibly using feeler gauged and trim as required. The gently pry between crank & block forward & rear to ensure clearance is consistently present regardless of crank "thrust".
So my thinking is there wouldn't be an advantage, except if you were running *very tight* clearances. Or maybe the advantage is cutting the material is easier with teflon?
#15
Instructor
Anyone ever install a scrapper while changing rod bearings and not while doing a full refresh?
Is there any issue removing the main bearing nuts on the crank girdle with motor in the car? That part worries me...
But it seems it's ok based on the Clarks Garage Crank Scrapper install
http://www.clarks-garage.com/shop-manual/eng-21.htm
Teflon version is the way to go as it also has a one way oil screen.
http://www.crank-scrapers.com/Porsche_944.html
Is there any issue removing the main bearing nuts on the crank girdle with motor in the car? That part worries me...
But it seems it's ok based on the Clarks Garage Crank Scrapper install
http://www.clarks-garage.com/shop-manual/eng-21.htm
Teflon version is the way to go as it also has a one way oil screen.
http://www.crank-scrapers.com/Porsche_944.html