Predator Engine block cracked!!!! Suggestions
Sorry folks.....thanks for all the input! I have not had much time to respond online as work has been KILLING me!
I truly appreciate the suggestions! I ended up ordering a replacement block for about 30 bucks and have almost completed the rebuild. As is often the case, I have run out of gaskets and am waiting for a new sidecover gasket.
Interestingly, the loose bolt theory struck a chord (thanks Newoldstock!). I remembered that the sidecover bolts freqently backed out (I was able to minimize this with judicious locktite).
Excited to get the motor back together (my son looks at me cross eyed because I ride the thing...and break it...continously.)
As far as bracing....I am not sure I have the skills to do that!
I truly appreciate the suggestions! I ended up ordering a replacement block for about 30 bucks and have almost completed the rebuild. As is often the case, I have run out of gaskets and am waiting for a new sidecover gasket.
Interestingly, the loose bolt theory struck a chord (thanks Newoldstock!). I remembered that the sidecover bolts freqently backed out (I was able to minimize this with judicious locktite).
Excited to get the motor back together (my son looks at me cross eyed because I ride the thing...and break it...continously.)
As far as bracing....I am not sure I have the skills to do that!
Did you buy a new block or a used block? NOS had a great suggestion with studs. If a used block, you better check the cover threads. If they show signs of wear, you might be better off with helicoils or studs on the case cover. A good hardware store should have grade 8.8 automotive studs. Put them in with permanent locktite on the block side and semi-permanent on the cover side. From my reading, kart associations recommend studs on the head, so stands to reason they won't hurt for the cover, too. As to a cover brace, OND or David Wulf might offer up a suggestion or two--along with several others who build clones.
If you have an industrial nut and bolt supplier in your area there is a real good chance he has some threaded rod you can buy that meets the 8.8 grade.
You can just cut this to fit.
Dr. Shop Teacher found some automotive studs I remember from a while back ( better idea probably cheaper _)
This next part is important:
DO NOT mix and match soft washers and hard bolts ect ect.
These are all part of a system and they will not stay tight if they are not the same grade.
I have seen hard bolts chew up soft washers and parts fall off of things ( where I work the Gopniks cannot be trained or educated they mix brass steel and stainless with every other kind of material sometimes it loose and falls off sometimes its seized and sometimes it causes corrosion problems )
I use just 8.8 grade bolts, flat washers and locks on the case, and just flats with the head bolts.
Eventually the case will loosen again too, this is something you must constantly watch OR you could just glue it up with loctite
If you happen to see this kit someplace https://images.duckduckgo.com/iu/?u=http%3A%2F%2Fmedia.midwayusa.com%2Fproductimages%2F880x660%2FPrimary%2F986%2F986916.jpg&f=1
Its some mighty fine glue in there!
I used that one time to repair a cast iron case and foolishly cleaned the holes with some loctite primer from a different kit ( it was actually CAT thread locker cleaner primer I used ).
I ended up snapping bolts in attempt to remove and repair the threads.
If it will do that to bolt then its a safe bet you can use the same process to glue in a set of case studs ( but don't ever expect to get the studs out again )
Oh ya another trick....
Take the dowel for the case and look at them...
They are hollow so I fill them with epoxy and use them that way to stiffen up the block ( reduce flex )
You could but I get nervous suggestion you fill and glue them directly in the block ( you could make a mess of it )
Next buy or make a top plate that goes where your tank was.
You could even cut up a tank in a pinch.
This helps brace things.
Under the flywheel where the lighting coils go make a brace that ties all 4 bolts together there too.
Case cover side tie all four holes together and make a plate that extends all the way to head.
tray and catch every bolt on the way to tin work for the cooling shroud.
make a plate that braces the low oil shut off inside the case ( even better if its a piece of angled aluminum that closes off the area and leaves a void where oil is not violently whipped around, this is not a windage tray its just a quiet place in the block where oil is not whipped into foam ).
Make a triangular plate that connects the ears for the fuel tank to the oil plug at the bottom of the block.
All these little braces make the block stiffer and reduce the flex( flex is what causes the bolts to loosen )
The blocks are not very strong and were not designed for this.
But you can make then stronger just buy adding some simple braces and above all good bolts tightened to 17 foot pounds.
Yes you can make a brace its easy.
Just find some 3/16 cold roll aluminum plate ( very common )
Cut drill and bolt on everywhere you see bolt holes not used on the block to tie things together.
I won't upload anything here anymore, but if your still stuck on this send me a PM and I will emmail you some pictures of easy bracing
You can just cut this to fit.
Dr. Shop Teacher found some automotive studs I remember from a while back ( better idea probably cheaper _)
This next part is important:
DO NOT mix and match soft washers and hard bolts ect ect.
These are all part of a system and they will not stay tight if they are not the same grade.
I have seen hard bolts chew up soft washers and parts fall off of things ( where I work the Gopniks cannot be trained or educated they mix brass steel and stainless with every other kind of material sometimes it loose and falls off sometimes its seized and sometimes it causes corrosion problems )
I use just 8.8 grade bolts, flat washers and locks on the case, and just flats with the head bolts.
Eventually the case will loosen again too, this is something you must constantly watch OR you could just glue it up with loctite
If you happen to see this kit someplace https://images.duckduckgo.com/iu/?u=http%3A%2F%2Fmedia.midwayusa.com%2Fproductimages%2F880x660%2FPrimary%2F986%2F986916.jpg&f=1
Its some mighty fine glue in there!
I used that one time to repair a cast iron case and foolishly cleaned the holes with some loctite primer from a different kit ( it was actually CAT thread locker cleaner primer I used ).
I ended up snapping bolts in attempt to remove and repair the threads.
If it will do that to bolt then its a safe bet you can use the same process to glue in a set of case studs ( but don't ever expect to get the studs out again )
Oh ya another trick....
Take the dowel for the case and look at them...
They are hollow so I fill them with epoxy and use them that way to stiffen up the block ( reduce flex )
You could but I get nervous suggestion you fill and glue them directly in the block ( you could make a mess of it )
Next buy or make a top plate that goes where your tank was.
You could even cut up a tank in a pinch.
This helps brace things.
Under the flywheel where the lighting coils go make a brace that ties all 4 bolts together there too.
Case cover side tie all four holes together and make a plate that extends all the way to head.
tray and catch every bolt on the way to tin work for the cooling shroud.
make a plate that braces the low oil shut off inside the case ( even better if its a piece of angled aluminum that closes off the area and leaves a void where oil is not violently whipped around, this is not a windage tray its just a quiet place in the block where oil is not whipped into foam ).
Make a triangular plate that connects the ears for the fuel tank to the oil plug at the bottom of the block.
All these little braces make the block stiffer and reduce the flex( flex is what causes the bolts to loosen )
The blocks are not very strong and were not designed for this.
But you can make then stronger just buy adding some simple braces and above all good bolts tightened to 17 foot pounds.
Yes you can make a brace its easy.
Just find some 3/16 cold roll aluminum plate ( very common )
Cut drill and bolt on everywhere you see bolt holes not used on the block to tie things together.
I won't upload anything here anymore, but if your still stuck on this send me a PM and I will emmail you some pictures of easy bracing
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