New hemi! abused hemi!

Gents I installed a hemi predator 212 this weekend - I'm totally lost ( I think ) idk.....

So my previous setup was - non hemi predator 212 - pvl flywheel - weenie pipe - top plate - fuel pump. Everything else is stock ( stock predator class ).......
I paired the engine with a 12 tooth clutch - 65 outback..... This has worked nicely for us ( won our first night out...
12/65 = 5.42 gear ratio......

Our next time out I bumped the gearing to - 13/71 = 5.46.
We ran good with this - 2nd in heat and feature..... Less bogging - engine stayed high in RPMs but never over revved....... I felt as if I was on the very edge.....


So the next weekend I ordered 11 tooth driver and 60th sprocket..... 5.45 gearing - I also went up a 1/2 in size on both rear tires....

We rained out for 4 weeks straight - Durning our down time a friend talked me into dropping on a brand new hemi....... Swears the hemi make more power.


This seems to be the point everything went wrong......

So this last Saturday - rain stayed away and we showed up with a brand new hemi.....
With the 11/60 gear installed - we went out for hotlaps..... Right away I notice the engine is floating valves at the very end of the straight away..... No mistaken - gearing was wrong......
Went into the pits and did a fast gear swap - back to what we know works ( 12/65 )....... Went back out for hotlaps and still had the issue - but not as bad......

I get back to the pits and at this point I'm thinking I have a running condition - not a gearing issue....... These are the same engines from what I understand the hemi just flows better........ At this point I'm scrambling trying to figure out the issue....... Not gonna name a name but someone at the track ( you would think ) knows what they are doing - told me to go up a gear size in the rear ( 3 tooth )....... Went out for the heat race with a 12/67 - same issue....... Engine would top at about 5200 rpms.....

We won our heat and believe it or not put some decent ground on the other drives......

Once again I'm in the pits....... This time changing plugs - coils - so on...... Again ( one of the top people tell me ) go up a gear or two more..... ( I went to a 70 in the rear )....

A main comes - it engine is worse then it has been all night..... Engine starter over revving mid straightaway... it took everything I had to keep my lead - all I could do is hold the bottom line and not swing up high on the straightaways........ It worked but I'm telling you - they wear all over me - any mistake and it would have been over..... Even tho we won...... I was cursing from the moment I took the checkered to the scale house - to my pit.....

All I could think was ( this motor is trash )...... After loading up and heading all I called a friend ( Chris cooper ) ( he is on here with us )......... After talking with him - turns out I was going the wrong way with the rear gear...... Should have been going down in size....... In my defense - I was told to go up..... However..... I'm very disappointed in how this weekend turned up - I should have known better - in fact I did know better but somehow it all got away from me......

Now that I know wear I went wrong....... One thing still bothers me.......
The 12/65 works perfect on our non hemi engine - but is not enough for our hemi engine..... Is there that much difference between the two - has anyone swapped between a non hemi and a hemi? The non hemi appears to be able to hold higher RPMs vs the hemi...... I would have thought the exact opposite....... Does my hemi engine have some kinda issue? Anyone else experience this?

also after running the engine in such a manner - should I junk it. Should I rebuild it....... I was advised to just change valve springs and it will probably be ok..... But idk I'm kinda uncomfortable running a engine that ways abused in such manor...... Thought and opinions please! Thanks all!
 
Gents I installed a hemi predator 212 this weekend - I'm totally lost ( I think ) idk.....

So my previous setup was - non hemi predator 212 - pvl flywheel - weenie pipe - top plate - fuel pump. Everything else is stock ( stock predator class ).......
I paired the engine with a 12 tooth clutch - 65 outback..... This has worked nicely for us ( won our first night out...
12/65 = 5.42 gear ratio......

Our next time out I bumped the gearing to - 13/71 = 5.46.
We ran good with this - 2nd in heat and feature..... Less bogging - engine stayed high in RPMs but never over revved....... I felt as if I was on the very edge.....


So the next weekend I ordered 11 tooth driver and 60th sprocket..... 5.45 gearing - I also went up a 1/2 in size on both rear tires....

We rained out for 4 weeks straight - Durning our down time a friend talked me into dropping on a brand new hemi....... Swears the hemi make more power.


This seems to be the point everything went wrong......

So this last Saturday - rain stayed away and we showed up with a brand new hemi.....
With the 11/60 gear installed - we went out for hotlaps..... Right away I notice the engine is floating valves at the very end of the straight away..... No mistaken - gearing was wrong......
Went into the pits and did a fast gear swap - back to what we know works ( 12/65 )....... Went back out for hotlaps and still had the issue - but not as bad......

I get back to the pits and at this point I'm thinking I have a running condition - not a gearing issue....... These are the same engines from what I understand the hemi just flows better........ At this point I'm scrambling trying to figure out the issue....... Not gonna name a name but someone at the track ( you would think ) knows what they are doing - told me to go up a gear size in the rear ( 3 tooth )....... Went out for the heat race with a 12/67 - same issue....... Engine would top at about 5200 rpms.....

We won our heat and believe it or not put some decent ground on the other drives......

Once again I'm in the pits....... This time changing plugs - coils - so on...... Again ( one of the top people tell me ) go up a gear or two more..... ( I went to a 70 in the rear )....

A main comes - it engine is worse then it has been all night..... Engine starter over revving mid straightaway... it took everything I had to keep my lead - all I could do is hold the bottom line and not swing up high on the straightaways........ It worked but I'm telling you - they wear all over me - any mistake and it would have been over..... Even tho we won...... I was cursing from the moment I took the checkered to the scale house - to my pit.....

All I could think was ( this motor is trash )...... After loading up and heading all I called a friend ( Chris cooper ) ( he is on here with us )......... After talking with him - turns out I was going the wrong way with the rear gear...... Should have been going down in size....... In my defense - I was told to go up..... However..... I'm very disappointed in how this weekend turned up - I should have known better - in fact I did know better but somehow it all got away from me......

Now that I know wear I went wrong....... One thing still bothers me.......
The 12/65 works perfect on our non hemi engine - but is not enough for our hemi engine..... Is there that much difference between the two - has anyone swapped between a non hemi and a hemi? The non hemi appears to be able to hold higher RPMs vs the hemi...... I would have thought the exact opposite....... Does my hemi engine have some kinda issue? Anyone else experience this?

also after running the engine in such a manner - should I junk it. Should I rebuild it....... I was advised to just change valve springs and it will probably be ok..... But idk I'm kinda uncomfortable running a engine that ways abused in such manor...... Thought and opinions please! Thanks all!
Step one. Think for yourself. You knew it was floating valves and listened to someone else and went the opposite way on gear.

Step two. Springs are cheap, change them and go back with the gear you knew worked on the non hemi. If it floats take a tooth or two off the back. Its possible you beat up the valve job but i would give it another night

Step three. Now that you have proven the motor is fine now you play with the "ratio is a ratio"
 
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flattop1

Dawg 89
Its a terminology thing .
High or low .
Up , higher or taller could be a 5.00 vs 5.46
 
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Step o

Step one. Think for yourself. You knew it was floating valves and listened to someone else and went the opposite way on gear.

Step two. Springs are cheap, change them and go back with the gear you knew worked on the non hemi. If it floats take a tooth or two off the back. Its possible you beat up the valve job but i would give it another night

Step three. Now that you have proven the motor is fine now you play with the "ratio is a ratio"
It's not a thinking for myself issue.... I got enough sats to reflect I'm pretty good at that..... It's a terminology issues for the most part mixed in with a lil bit of being new.....

When I was dealing with the situation - I didn't really know what was going on...... Especially when I went to the same gearing the non hemi had........ That's what threw me off - I couldn't believe there was that much difference between the hemi and non hemi.... Im originally from big car racing..... Sprint car ...... When we speak ( add gearing ) we typically are looking for more straightaway speed...... I guess it's a terminology issue...... When I was increasing the rear gear size - I thought I was adding more gear for the straightaway......

My original concern was not so much setup help.....
My concern was ( how much abuse is to much for these engines ) did I fatigue the crank or rod ? Do I need to junk it...... I'll take your advice and just change springs.

I'll have to start with a lower gearing and work my way up ... The gearing for the non hemi won't work.
 
Its a terminology thing .
High or low .
Up , higher or taller coulb be a 5.00 vs 5.46
Agree! That's what we wear all talking about in the shop.... It all depends on how your talking about it.
I kept saying add more gear ( for the straightaway ) so he told me add more teeth in the rear....
 
Agree! That's what we wear all talking about in the shop.... It all depends on how your talking about it.
I kept saying add more gear ( for the straightaway ) so he told me add more teeth in the rear....
Gotcha i didn't catch that from your post.

Unless you got a turd or your other one was the exception you really shouldn't see that much difference between the two.

Is gary allowing guys to shim the springs? The hemi stock springs i believe are heavier than the a/m 10.8 springs
 

GClary

Member
Engine should be fine , the rod can take it ok . Go the other way on the gearing . I wouldn't change the springs , at least not until you get it back out on the track and see how it does . I have seen in some posts that the springs seem to get better over time , then fall off rapidly .
 

josheezpapa

Member
My guess is that the valves were a bit loose.. the engines come out of the box running good enough for power quipment or sometbing..
I'd re check lash, throw a 64 on the axle and try again.
Also remember.. same track, driver, engine and all may need a bit different gear from night to night... maybe even within the same night...
Different surface, different air density, even fuel quality can matter
 
My guess is that the valves were a bit loose.. the engines come out of the box running good enough for power quipment or sometbing..
I'd re check lash, throw a 64 on the axle and try again.
Also remember.. same track, driver, engine and all may need a bit different gear from night to night... maybe even within the same night...
Different surface, different air density, even fuel quality can matter
I'll try adjusting valves and replacing springs.......
The 12/65 on the non hemi was perfect...... It's what I was recommended by one of the locals who is known for winning....... It has worked well but ( in my opinion ) bogged a lil much coming off the corner..... But again it's proven to be a winner....... With the 12/65 - at the end of the straightaway there was still more rpm to go......wasn't close to floating valves.........

With this hemi..... It floats - and does it bad...... Even with the 12/65 - right as you get to the turn.......

To me it was so bad..... It almost felt as if I had a rev limiter on..... 5200 RPMs and that was it......
They wear clearly two different engines that night.

I'll give your advice a try and see what happens!
 
Gotcha i didn't catch that from your post.

Unless you got a turd or your other one was the exception you really shouldn't see that much difference between the two.

Is gary allowing guys to shim the springs? The hemi stock springs i believe are heavier than the a/m 10.8 springs
Gary said we can change the springs to 10.8 clone springs....... It's my understanding - because stock predetor springs are hard to find..... So he allows the clone springs to make things a lil easier.

I wouldn't have ever thought there would be that much difference between the two..... It's was night and day.... One literally bogs coming off the corner and sounds great at the end of the straightaway....... The other sounds great getting outta the turn but is trash at the end of straightaway.....

Even Gary was wondering if maybe something is internally wrong.....
 
We even started thinking maybe the governor is still engaging somehow but there is no way that is possible - it's disconnected on the outside and internally.
 
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OVALTECH1

Premium User
The hemi has way more valvetrain mass and will float out sooner than the non. The springs will be fine just drop your rear gear down 3-4 teeth. How big of a track do you race on? I can’t even fathom a predator of an 12 driver. Also does your hemi predator have the pipe and other mods done to it as your non hemi ?
 
The hemi has way more valvetrain mass and will float out sooner than the non. The springs will be fine just drop your rear gear down 3-4 teeth. How big of a track do you race on? I can’t even fathom a predator of an 12 driver. Also does your hemi predator have the pipe and other mods done to it as your non hemi ?
Place is smaller than small. Its about the size of most small indoor tracks.
 
The hemi has way more valvetrain mass and will float out sooner than the non. The springs will be fine just drop your rear gear down 3-4 teeth. How big of a track do you race on? I can’t even fathom a predator of an 12 driver. Also does your hemi predator have the pipe and other mods done to it as your non hemi ?
I believe the word is 1/10th mile..... I could be wrong but that's what I was told.

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