Head gasket issues

#21
Several people have asked you ( myself included ) how many lb. ft. did you tighten the nuts on the head. I'm guessing you don't know. I have ruined two
predator non hemi engines doing what I think you just did. Pretty stout builds, much like yours and with high compression and head studs instead of bolts my thinking was well I am going torque these to 30 lb. ft. It will hold
better, RIGHT? Well what it does is stretch and deform the block so it can't
seal. The first time it happened I had the top of the block ground flat. Cost me $100 for that. The 2nd time it happened it did it to 2 karts on the same day ( similar builds ) and this time where the gaskets blew it scorched and melted a channel on both the block and the heads, deep enough that they were junk. Only bare blocks I could find were hemi's and the cam journal sizes are different. Had too buy two new engines and swap over all my good
parts and have the new heads milled and ported. EXPENSIVE LESSON.
It was Eric Adams at O.M.B. Warehouse the Grey Goat that got me straightened out on this. Get the top of your block checked for flatness by a machine shop, and repaired if necessary. Then buy the .045" thick fiber head gasket with the fire ring ( go power sports has them in stock ) and torque the head to 20. No more. And do it incrementally and in a criss cross
pattern. The conversation about venting have NOTHING to do with your problem .
 
#22
Several people have asked you ( myself included ) how many lb. ft. did you tighten the nuts on the head. I'm guessing you don't know. I have ruined two
predator non hemi engines doing what I think you just did. Pretty stout builds, much like yours and with high compression and head studs instead of bolts my thinking was well I am going torque these to 30 lb. ft. It will hold
better, RIGHT? Well what it does is stretch and deform the block so it can't
seal. The first time it happened I had the top of the block ground flat. Cost me $100 for that. The 2nd time it happened it did it to 2 karts on the same day ( similar builds ) and this time where the gaskets blew it scorched and melted a channel on both the block and the heads, deep enough that they were junk. Only bare blocks I could find were hemi's and the cam journal sizes are different. Had too buy two new engines and swap over all my good
parts and have the new heads milled and ported. EXPENSIVE LESSON.
It was Eric Adams at O.M.B. Warehouse the Grey Goat that got me straightened out on this. Get the top of your block checked for flatness by a machine shop, and repaired if necessary. Then buy the .045" thick fiber head gasket with the fire ring ( go power sports has them in stock ) and torque the head to 20. No more. And do it incrementally and in a criss cross
pattern. The conversation about venting have NOTHING to do with your problem .
I did mention the torque on earlier threads. 20ft lbs. and thanks bro. I’ll see what I can do to help this issue
 

SAS289

Well-Known Member
#23
Several people have asked you ( myself included ) how many lb. ft. did you tighten the nuts on the head. I'm guessing you don't know. I have ruined two
predator non hemi engines doing what I think you just did. Pretty stout builds, much like yours and with high compression and head studs instead of bolts my thinking was well I am going torque these to 30 lb. ft. It will hold
better, RIGHT? Well what it does is stretch and deform the block so it can't
seal. The first time it happened I had the top of the block ground flat. Cost me $100 for that. The 2nd time it happened it did it to 2 karts on the same day ( similar builds ) and this time where the gaskets blew it scorched and melted a channel on both the block and the heads, deep enough that they were junk. Only bare blocks I could find were hemi's and the cam journal sizes are different. Had too buy two new engines and swap over all my good
parts and have the new heads milled and ported. EXPENSIVE LESSON.
It was Eric Adams at O.M.B. Warehouse the Grey Goat that got me straightened out on this. Get the top of your block checked for flatness by a machine shop, and repaired if necessary. Then buy the .045" thick fiber head gasket with the fire ring ( go power sports has them in stock ) and torque the head to 20. No more. And do it incrementally and in a criss cross
pattern. The conversation about venting have NOTHING to do with your problem .
Yeah. I would never start with a non hemi Predator 212.
 
#25
I'm in southern California and have never even seen the Hemi in the small block, 212cc. Might have something to do with the EPA in this ridiculous state. TOO MANY regulations.
 
#26
I'm in southern California and have never even seen the Hemi in the small block, 212cc. Might have something to do with the EPA in this ridiculous state. TOO MANY regulations.
I’m in Indiana. The non hemi is hard to get here. Hemis all day at harbor freight in my city haha. I have like 3 new in the box. And tbh I went with a non hemi aftermarket head bc I ordered non hemi rockers on accident and couldn’t return them. So I got a head for them. Lol.
 

SAS289

Well-Known Member
#27
Sas289: I'm green on predators, but curious why you'd stay away from non hemi?
The non hemi 212 has a unique engine block that has a larger cam journal than all others. All others being GX200 and 196 clones, Ducar, Tillotson, Wildcat, Predator Hemi and 224. The Predator 212's also have a unique crankshaft flywheel taper.

If a guy built a potent 196 with $200 plus in a cam and flywheel and wanted to upgrade to a Wildcat 223 he could use the cam and flywheel from the 196 on the Wildcat. If you started with a built non hemi 212 and wanted to upgrade to a Wildcat you would be buying a new cam and flywheel for the Wildcat.

Early this year I did a mild build on a 224. If I wanted, I could have used the flywheel, cam, Champion rockers, and billet rod from my 196. All fit the 224.

The Ducar, Tillotson, Wildcat, and 224 are a better starting point for a big power high RPM build because they have a higher strength block than the clones and Predator 212's.
 
#28
Don't feel bad or guilty about putting a built non hemi head on your hemi
engine. I'm sure you've noticed most all hopped up heads ( high compression, big valves, and ratio rockers ) are in the non hemi or wedge head configuration. Much less valve to piston clearance problems.
 

SAS289

Well-Known Member
#30
Don't feel bad or guilty about putting a built non hemi head on your hemi
engine. I'm sure you've noticed most all hopped up heads ( high compression, big valves, and ratio rockers ) are in the non hemi or wedge head configuration. Much less valve to piston clearance problems.
Yes. The straight valve head was one of the reasons I got a 224. Was easy to get appx 9.7:1 CR with a flat-top piston right at the deck and a .036" head gasket with the stock 22cc head. There's no concern about clearance. You have to be more careful with the hemi head.
 

Triley41395

Well-Known Member
#32
Make sure your not bottoming the nuts out on the threads. A friend of mine built a small block chevy and replaced the head bolts with studs. After it was finished it made it about 15 seconds on the dyno then boom blew the head gasket. Turns out the studs were about .02 thousands to long, the nuts although torqued to spec were really not tight.
 

Minimichael

Well-Known Member
#33
Following the thread, and commenters more knowledgeable than I, I'm still wondering shouldn't the compression still be a suspect here? Somebody referred to a flat-top piston being flush at TDC... Tatueric says it's got a 14cc head. So, if we assume his piston hits flush at TDC, is a 14cc head enough space to accommodate? I mean, doesn't 212 divided by 14 equal 15.14:1?
 

SAS289

Well-Known Member
#34
Following the thread, and commenters more knowledgeable than I, I'm still wondering shouldn't the compression still be a suspect here? Somebody referred to a flat-top piston being flush at TDC... Tatueric says it's got a 14cc head. So, if we assume his piston hits flush at TDC, is a 14cc head enough space to accommodate? I mean, doesn't 212 divided by 14 equal 15.14:1?
They say you want .030" clearance from the top of the piston to the head. As an example, if the piston was .020" in the hole you want a .010" head gasket to be safe from crankshaft flex. In this example if you had a 14cc head and a flat-top piston you would be around 12:1 CR on a 196.

I used an online CR calc to see what compression i should get. Was a little complicated but I eventually got the right numbers in the calc.
Engine Compression Ratio (CR) Calculator (csgnetwork.com)

CompressionChart.png
 
#35
Real head studs are threaded on both ends and are made out of quality steel. When you question about all thread, I vision basically common threaded rod. This is very poor quality steel. Good for building gates for your back yard and such. Not intended for engine building.
 

Triley41395

Well-Known Member
#36
Real head studs are threaded on both ends and are made out of quality steel. When you question about all thread, I vision basically common threaded rod. This is very poor quality steel. Good for building gates for your back yard and such. Not intended for engine building.
I agree with what you're saying about the all thread. I know what the studs look like on a car but I've never built on of these small engines so I had to ask. It's the threads on both ends that could cause a problem, or should I say the lack of threads in the middle. Most of the parts are made in China so quality control is not the best. If his block is not threaded deep enough or the studs are not threaded far enough down then the space where there are no threads might be sticking up just enough above the top of the head for the nut to bottom out, it wouldn't take much,or have to be all off them and might not be obvious.
 
#37
All the above. Plus, clean the bolt holes really good. Clean the bolts as well. I use one drop of light oil on the bolt threads.
Then creep-up to the torque spec in increments.
My bad, just read Predator. Principle still applies. Check to make sure you have sufficient threads to torque without bottoming-out, or running out of thread form.
 
#38
I have purchased 3 head stud kits. Two from Go Power Sports and one from
O.M.B. Warehouse. The ones from GPS seemed to be of better quality, or let's just say the machine work seemed better. I think they cost about $3
more than the others. In both cases they worked great. Overall stud length
as well as length of threaded ends. I'm in no way defending Chinese workmanship because some of it is horrible, but something as simple as overall length and amount of threads they seemed to have gotten it right.
On the subject of poor quality one thing I would recommend is prior to installing the studs get a tap ( size and thread pitch escape me at the moment ) oil it well and run it into the holes in the block. Clean with alcohol or break parts cleaner and blow out with air. Some of the threads at the end of the holes leave something to be desired. Could prevent the stud from going all the way in.
 
#39
On the subject of poor quality one thing I would recommend is prior to installing the studs get a tap ( size and thread pitch escape me at the moment ) oil it well and run it into the holes in the block. Clean with alcohol or break parts cleaner and blow out with air. Some of the threads at the end of the holes leave something to be desired. Could prevent the stud from going all the way in.
Aka run a "Bottom Tap" thru it and clean out the holes. Makes total sense.
 
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