The old myth that both sides argue back and forth about having a stock ls bottom end and just bolting on a VTEC head, and getting valve to piston clearance issues. Both sides of the argument swear on their own behalf. We have to remember that there are both USDM and JDM B18B motors.

With that being said, what's the truth?

How about with ITR cams? lol

 

Uhh, I have never heard this "myth." Do you have it confused with B20 v. reliefs?

 

Anything other then stock B16 cams you will have valve/piston issues with stock LS pistons.

 

Never heard of this myth, just that its an important rule of thumb to check P2V clearances in an un-stock motor (hybrids included), especially if the valve reliefs were cast for smaller sized valves from the LS head.

 

not a myth....

 

The valve reliefs on the intake side of LS pistons are smaller than the intake valves in a vtec head. This is not an issue unless you have cams with significantly more lift that of stock. Claying the motor is really the only way to know for sure

 

yes anything bigger then gs-r cam. your intake valves with slightly tap your piston. very very light tap but enff to set off the knock senors and retard your timing ... use a dremel and open the valve relief for a vtec valves size or just swap out for some vtec piston, something i did when i was broke back in the days.. worked fine for me..

 

well my buddy ran type R cams in his stock LS vtec ran great until he threw a rod and well that ended that motor...

 

Was that because the valve kept tapping the piston, causing NO oil clearance of the rod bearing/crank, which then failed, overheated the rod, and caused it to break? Tell him ha did a good job.

 

no it ran like a champ but he did not change the rod bolts to ARP and it threw the rod at like 8,400 RPM just finishing the 1/4 mile but he had not problems...it was just he did not use the ARP rod bolts...it lasted him a year and half....

 

moral of the story " I would rather be lucky than good" Do you know the tensile strength differance between the 8mm Honda bolt and Arp 8mm bolt?

 

yeah i use arp rod bolts...in my ls vtec

 

So the differance in PSI strength is what?

 

i don't know i just know you can rev up to like 8500RPM with ARP bolts and not throw a rod...unlike with the ls rod bolts

 

So from what i'm gathering, i'll have approx. 9.6 compression ratio with the B16a head. I don't or didn't plan on spinning the motor over 7100 rpm, that is, only because it's a 1.54 rod ratio. Geez I kind of knew that going into the deal. This motor throws a lot at the cylinder walls with its rod angle the way it is. However, if you guys are going past 8K rpm with these little motors, then that's cool. So with ARP rod bolts, the most I (personal preference) would ever turn this motor is 7800 or maybe 8000 on a bad day. I'm just wondering if the stock head bolts will be fine at just over 7000 rpm's, or more like a maximum of 7500 rpm's.

However, and taking a look at things, I would more than likely be cutting it close in regards to valve to piston clearance. I do have a dremel grinder kit at my disposal. Therefore, I could do some hand machining to the valve reliefs. No prob there, but I would really like to run the ITR cams that I have just laying there. I guess it's just a matter of me getting off my lazy butt and grinding the valve reliefs.

It's difficult for me to push myself to put such cams in a motor that will only put out a maximum of about 9.6 compression ratio. Well, i'll just have to think about that part of the game just a bit more.

Lastly, I will be spraying nitrous. I'm not leaving the house without it. No way. Not in a heavy integra. Not a chance. lol

So in the end I guess I really need to consider what will happen when putting a pair of ITR cams in a motor, with 9.6 compression ratio, that will only turn just over 7000 rpm's, will actually do. It might be a lame *** motor. However, I really don't know this for sure yet. Perhaps I should set a goal to turn the motor up to a maximum of 8000 rpm's, but I am just not sure right now.

Thanks to all that replied to this thread. You have been a great help to me whether you think you haven't or not. Reply to this last post if you please since I would really appreciate it.

Thanks again!

 

Just notch the IN valve reliefs for the 33mm valves and be done with it. As ounce of prevention. Masking tape and a dremel.

 

Im gonna guess in the neighborhood of 350,000 psi tensile strength...
Am I close?

 

I think thats ARP's advertised rating, not the difference.

 

u crazy!... its a myth!


if anyone cant figure out this by themselves... well they haven't done much engine work then...

 

It's a myth.

 

i have a few like those too from nubs building engines

 

So true.