Different valve covers????

Graham1728

New member
Ok still a total newbie here, I recently bought two older karts from two different sellers for my daughter and I. Both motors are yellow and both say box stock project on them. However, one of them has the 4 bolt valve cover I see all over the web. The other has a 5 bolt valve cover. The other difference is that the "OHV" is written up and down instead of side to side. I can't find another one like it on the web????

Is this just a older style or something?

Thanks, Ryan
 
Some people will put the 5 bolt greyhound heads on the BSP engines for the better flow advantage of some of those 5 bolt greyhound heads. The 02 casting # 5 bolt was a really good flowing head, the valves were sunk a little lower into the floor of the chamber, which increased flow. I have a L01 5 bolt head that is the same way but better overall casting in my opinion.
 
Some of the 5 bolt heads are a little better, but most I've seen are not AKRA legal because of the sunken valves.
 
As a past techman I would have to toss someone who put a 5 bolt head on a 4 bolt head (yellow or red style) block..do to the fact that the 5 bolt head never came on a yellow style block 5 bolt heads were on HF blocks and the side cover & block are cast different, so interchanging of these parts are not "as compared to stock part"
 
Thanks for all the info. So I guess my next question is how do I know if it is a Harbor Freight head on a box stock project motor or is it a Harbor Freight motor with a yellow side cover and Box Stock Project stickers?
 
As a past techman I would have to toss someone who put a 5 bolt head on a 4 bolt head (yellow or red style) block..do to the fact that the 5 bolt head never came on a yellow style block 5 bolt heads were on HF blocks and the side cover & block are cast different, so interchanging of these parts are not "as compared to stock part"

The rules do not say the head must match the block. 4 and 5 bolt heads are still legal as far as I know. I'm miffed as to your interpretation of the rules. maybe I missed something in the rulebook...
 
The rules do not say the head must match the block. 4 and 5 bolt heads are still legal as far as I know. I'm miffed as to your interpretation of the rules. maybe I missed something in the rulebook...

Exactly. If what he said applies, then the builders who blueprint engines by handpicking parts have building illegal engines for years, since by the time they are done with an engine, it may have parts from ducar, dupor, greyhound, bsp and other engines in it. That is no different than using a 5 bolt head on a newer block. a 6.5 clone head is a 6.5 clone head as long as it meets the specs, no matter how you cut it. If the rulemakers did not want people using different heads than what came on the block, they would have put it in the rules. A 5 bolt head can be compared to any other stock head just the same as any other head can, the valve cover or how many bolts it has is not part of tech, not in any rule set i have ever seen.
 
Thanks for all the info. So I guess my next question is how do I know if it is a Harbor Freight head on a box stock project motor or is it a Harbor Freight motor with a yellow side cover and Box Stock Project stickers?

Box Stock Project blocks have Box Stock Project engraved on the front of the block where you would normally see a serial number on other clones. As far as being able to tell which block you have other than the BSP blocks, the blue HF blocks had different ears on them where the tank mounts than the yellow ones have. As far as being able to tell on the heads, that is next to impossible since there are so many different castings that came on all different blocks, except the 5 bolt head which only came on the greyhound blocks. If we werent allowed to use different heads and blocks, or other parts from different motors, blueprinting would not be allowed, and since that is basically something that cannot be controlled in tech, it has to be allowed. Show me a tech man who can tell if an engine has been blueprinted or not, i doubt there are many, if any out there. Also, there are blue motor blocks out there with the same side covers as some of the early yellow motors, i have one of them here now.
 
Why would having the valves sunk cause an improvement in flow?

Why is it illegal to sink the valves in the head? Have you flowed a greyhound 5 bolt head compared to a yellow or red clone 4 bolt head? Or have you compared the flow rates on heads with valves sunk vs unsunk? How could it NOT cause an improvement in flow when your valves sit flush with the floor of the combustion chamber?
 
Why is it illegal to sink the valves in the head? Have you flowed a greyhound 5 bolt head compared to a yellow or red clone 4 bolt head? Or have you compared the flow rates on heads with valves sunk vs unsunk? How could it NOT cause an improvement in flow when your valves sit flush with the floor of the combustion chamber?

I did not ask why it is illegal.

No I have not flowed all of the engines you have asked about?

Please post your Data or flow numbers I would really like to ingest it.

I would assume that a valve sunk into the head compared to a valve that is not sunk into the head at the same lift, would flow less.

But your flow data will clarify my misjudgement.

I don't think a valve sitting flush with the combustion chamber floor is considered sunken.
 
From my experience, I want a intake valve NOT sunk, now the exhaust may be a little different. Un even valves seem to help flow at overlap, your results may be different than mine though.
 
I too have often wondered about the "sunken" valve rule. I prefer my "raised" unshrouded valves. On another point. The Box Stock Project engine is the engine that is used as the "compared to known stock part". All have been pummeled with the "if it doesnt say you can then you cant" phrase many many times. With that said, Is the 5 bolt head legal at all? The rules do not say you CAN use one. It is clearly not the same when compared to a known stock part. True Box Stock Project engines never came with them. It is argued by many that a clear performance advantage MAY exist with the use of a good 5 bolt head. There are several ways the rules are written to make it "illegal" but none I can find that makes it "legal". Just saying for discussion.
 
I too have often wondered about the "sunken" valve rule. I prefer my "raised" unshrouded valves. On another point. The Box Stock Project engine is the engine that is used as the "compared to known stock part". All have been pummeled with the "if it doesnt say you can then you cant" phrase many many times. With that said, Is the 5 bolt head legal at all? The rules do not say you CAN use one. It is clearly not the same when compared to a known stock part. True Box Stock Project engines never came with them. It is argued by many that a clear performance advantage MAY exist with the use of a good 5 bolt head. There are several ways the rules are written to make it "illegal" but none I can find that makes it "legal". Just saying for discussion.

I have to agree with Jeff, I have told people the 5 bolt valve cover head wasn't legal (as that's what I had been told), was I wrong? If so, I have some heads to try.
 
Just something I'll throw out for thought:

There's always discussion over engines and trying to get a speed advantage... It's "harder" to get a few tenths out of a motor than it is from the kart itself...at least for me. What I see after a money race, is the motor is taken off the kart, carried to the tech room, the kart is pulled back to the trailer... does anyone ever "tech" a kart anymore? I'm just sayin', that I believe while everyone has their eyes on the motor in the tech room, the real speed producer has just been locked away in the trailer..... JMHO.
 
Oh yes we always impound the kart and engine together, and you are right. If there are chassis rules it is important to enforce them.
 
Oh yes we always impound the kart and engine together, and you are right. If there are chassis rules it is important to enforce them.

I'm just saying it's a lot easier to get a few tenths from ratchet hubs, slip joints, recapped tires, vulcanized sidewalls…etc than it is in the motor… They'll fight over .001" in engine tech and the kart will roll back to the trailer with the only tech on tires being if whether or not they have blue or pink lettering for Pro classes or orange or green for EL classes…..YET, we hear all the time, "it's all about the tires in karting"… The engines are watched so close and measured so accurately, if I wanted to cheat, I'd be looking elsewhere besides in that area...
 
i'm just saying it's a lot easier to get a few tenths from ratchet hubs, slip joints, recapped tires, vulcanized sidewalls…etc than it is in the motor… they'll fight over .001" in engine tech and the kart will roll back to the trailer with the only tech on tires being if whether or not they have blue or pink lettering for pro classes or orange or green for el classes…..yet, we hear all the time, "it's all about the tires in karting"… the engines are watched so close and measured so accurately, if i wanted to cheat, i'd be looking elsewhere besides in that area...
so true!!
 
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