Hi all,

Im about to rebuild the engine on my DC2 and would like to seek some opinions. Im running an LHT cooled JRSC setup at 9psi.

I bought the car stock and before I put on the JRSC, we measured the compression and it was 215psi @ all 4 cylinders.

Not long after the JRSC was put in, engine started losing power. Compression started to drop on 2 of the cylinders significantly. I thought it was piston failure due to a bad tune.

Checked the compression before taking apart the engine


After taking apart the engine, we found out that the pistons and cylinders looked fine.
The loss of compression was from the valves. My cyl head has a ghetto local port job when I bought the car and they even cut off the valve guides. That probably caused the valves to wear out.




So Ive decided to get a stock head, replace the valves, springs, retainers.

Ive come up with this list of parts for the engine rebuild. Would like to think what you guys think.

1. CP pistons at 11:1 compression (10.5-10.7 on a Type R head)
2. Manley rods
3. Supertech valves
4. Supertech valve springs/retainers
5. ARP head studs
6. Gates timing belt
7. Walboro pump

 

Ill get some pics of the pistons, rods, and valves and post them up soon.

 

my buddy ran the jrsc lht set up in a stock b18c1 i believe at 9psi and made 277hp. good luck with the build.

 

277whp!?!
Mind to share the tune?

 

Don't be so impressed by numbers alone.

Your last tune was done on an ol' skool Bosch dyno that couldn't even produce a torque reading.

 

I wouldn't go higher than 11:1 C/R. 8-10psi should good for 240-260 @ the wheels tuned. 170-190 on the torque. Make sure you get a good tuner, these things are known for detonation if timing isn't kept in check. That's what killed my C5 with the Jackson. GL on your build.

 

Im going with the CP 11:1 piston, thats supposed to get me 10.5-10.7 on the ITR head.

 

what's wrong with the stock pistons?

get the bottom end honed, proper rings and bearings

stock head, (p & p if you want, but do it right this time), stock everything else

anything aftermarket wouldn't benefit you a great margin since ur running LHT JRSC, stock spec imo would last you the longest

of course, a goood tune with s300

 

That's the inherent problem. While many of you are used to having competent tuners who offer reasonable rates for tweaking a simple setup like this, there really isn't anybody who is experienced to do so in Hong Kong.

So with that said, the forged internals will be more robust and hopefully will offer some buffer against this inexperience.

 

f'k that, all it takes is one good batch of detonation to crack a stock ringland. oe itr pistons are weak and while fine for NA apps, dangerous on boost

couldn't agree more on going forged and going for 10:6-1 compression. the extra PWC and rattle on start up is worth not worrying.

also, op, that head doesn't look that abnormal. did you do a vacuum test to see if the engine maintained 22- 23" of vacuum? it totally could be the case, but a lot of R's on boost, myself included wind up with similar compression numbers due to cracked ringlands. even a hairline fracture really increases blow by

when i tried to boost my R engine even with a good tune i had similar compression numbers after the first week.

 

I did not do a vacuum test, never heard of it. How is it done?
The problem should be from the valves cuz they were worn. Ill take some pics and post them up later. Maybe the valve seals were bad, maybe the cut valve guides contributed to the problem too, but oil was leaking through the valves. You can see the valves were all oily and dirty in the pics..

 

A Vaccum Test means 測試TURBO入氣Pipings有無漏. Vacuum leaks lead to insufficient air in the combustion process which may result in low compression on some cylinders. BTW, HK FTW!

 

We didn't put every piston that was removed under a microscope but the ringlands all looked good to the naked eye. The motor has had an odd history with the original P73-00s removed in favor of some P30s.

Don't worry about the vacuum test - you won't find it or many other standard procedures in Hong Kong. The valve seat was smashed pretty flat. Without relying on a vac. test, the basic brake kleen/gasoline test poured into the combustion chamber led to the discovery of leaks.

HK FTW for shopping and eating, but definitely FTMFL with regards to car tuning.....

 

Haha!!
Thanks for the reply with some Chinese characters. But sorry I can't really read Chinese!!!!
Am I accurate to say that my car will idle at a Wierd vacuum rate if there is a vacuum leak? If so, what numbers should I be reading on my boost gauge?

Cheers.

 

vacuum leak will show up on your boost gauge as a negative number but fluctuate.

 

Took a few pics of the valves and pistons and the cut off valve guide.

Here is the intake valve, notice how its all oily and dirty. Also, the silver part on the edge, it kinda has a concaved groove when you feel it.

 

I totally disagree with your opinion about car tuning in HK. there are ton of good tuners over there. Comparing to the tuning scene in the U.S, HK has higher barrier to open a tuning shop. Their quality can campare to Japanese. In U.S., tuners just rely on common theories instead of "real-track experience". I'm from California and that's what I think.

 

You have to experience what's in HK to really know. It's sad. There aren't many good tuners cuz there really isn't a need for one. Everything is marketing based. Ppl don't give a **** of their stuff performs. They just wan show off.
How I wish my car was stateside.

 

we can agree to disagree.

The main reason being HK has no track. It's heavily reliant on selling via hype. The popular consensus is "it's a Japanese car, obviously use Japanese parts." While there are obviously some US tuners who rely on theory, that theory can be quickly proven at the dragstrip/track...not something so easily done in HK.

I'm not saying all JDM parts are junk but there's a reason why the Japanese tuners specialize in certain realms - like handling and balance while the American tuners are known for producing power.
B-series development has all but stopped in Japan but still continues (albeit much slower now) in the states.

Even local HK tuners admit this very fact. Yeah my original opinion came on strong but you can't deny that the other significant fact is that any modifications are technically illegal in HK, so the scope of experience is diminished vs the those in the states who can more or less, freely modify as they please.

 

GL on the rebuild

 

what's the reason

all ears

 

The B is old.

The K is the new darling of the aftermarket and most parts now are being developed for the K both stateside and in other markets.

When was the last time Toda/JUN came out with a cam for the B?

I'm pretty sure Skunk2 and their pro-series would put all off the shelf JDM cams to shame nowadays.

 

Excellent opinion! but I'm saying that the HK industry has higher quality overall in either car tuning or repairing than the states do, you are getting away from my point of view. It's fact that the states have easier access for tuners to prove their so-called theories, but longer freeways, higher speed limit, and linear regulations on mods do not necessarily mean higher tuning quality. Good tuners will not be limited by geographical disadvantges.

 

shouldn't we be listening to the guy who actually lives in HK?

i'm not sure about you guys but i have no clue what the HK market is like

i really feel for beat though. my jdm itr met the same fate under boost

 

My question really is, how does a good tuner get proficient if he/she does not have access to places where they can test if the tuning they've done has made the car gone faster? Yes there are dynos here in HK, but what of them? A car that performs well on a dyno doesn't necessarily mean that performance will translate to the track or in this case in HK, the streets.

There is no question in my mind there are knowledgeable shops here but they can't help but wish there was a track here to prove their mettle. There isn't even a drag strip here. The quality you speak of I feel is how a car is prepared/painted/parts are installed. I will give you that, but beyond the actual install of components, having somebody here who knows what they're doing with the ECU is few and far between.

Why do you suppose they still fly people over from Thailand/Japan/USA to TUNE the cars here? It's because they can't do it or don't understand what's going on. And that here, is the actual limitation of a tuner due to the exact geographical location of HK.

Again, I'm speaking specifically about ECU tuning and engine tuning/assembly.

beat and I live here, he knows all about the tuning market based on his own personal experiences and he's had to go beyond the local market to seek information. Nobody even knew about the LHT aftercooler here. They weren't even aware of Hondata till a few years ago as they always felt and some STILL feel a static ECU *read N1* from Mugen or Spoon is the 'best' for their Honda.