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Engine Head needs valve job...

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Dapperz

Proven Member
35
0
Feb 23, 2016
Hot Springs, Arkansas
So I am buying an engine from a friend for a great price but it needs a valve job. I figured since I was going to have to do that I should go ahead and refresh some parts along with it. What are some recommendations on valves? I am shooting for the 400hp mark so should I upgrade to other than oem valves? Should I replace other parts?
 
Dapperz, you should be fine with stock valves - they are quite tough really. If you plan on upgrading camshafts beyond the typical 264/264 setup, or plan to rev past 7500, it would be a good insurance policy to upgrade your valve springs too. Upgrading springs as part of the rebuild will save time and money down the road, but of course it does add to the cost. I've heard bad things over the years about Brian Crower springs... for example: http://www.dsmtuners.com/threads/bc-spring-broke-in-half-and-destroyed-head.360359/
 
The reason for the rebuild is because there was low compression in one cylinder before he removed the engine. I was told that it had a bad valve and that a valve job would remedy the issue. I don't mind spending money where I need it and have already thought about upgrading cams and springs. I was just wondering whether the investment in stronger valves would be more beneficial with the power (400 hp) I'm wanting to push.
 
I'd go for upgraded springs and retainers rather than upgraded valves, personally. The valve just opens and closes all day, it doesn't really care how much power you are making as long as it's big enough to let the required air in :) At some point, oversize valves (+1mm) can help make more top-end power, but you don't need oversize valves for 400 horse @ 7500 RPM.
 
I was just wondering whether the investment in stronger valves would be more beneficial with the power (400 hp) I'm wanting to push.

Not at all.

The OEM valves are plenty strong enough to make 400hp, plus alot more.

If you are dead set on spending money on valves, I certainly would not spend the money to buy "stronger valves" without also paying the machine shop to fit +1mm valves to it, with a nice 3 or 5 angle valve job as well though. At least you would actually see some gains with that.

The OEM valves, in the standard size are more than strong enough to hit your power goal though, and you'd be much better off putting the extra money you would spend on valves towards springs/retainers and cams instead, at least they will help you reach your power goal.
 
I would run a leak down test first to confirm that it is a valve. Whatever shop you send it to would check the head and components and run a pressure test on it before any work began but it would be more cost effective to rule out rings or HG first. If you have a bent valve you will have no compression in that cylinder...not low compression.

As previously said, you do not need oversized valves for 400whp. I would recommend upgraded valve springs and camshafts though...and of course V3 HLA's...while you're in there. If this is a 2g head (no profile or mention of this yet) then mild port and polish could help as well.
 
It's a 98 GS-T, so it's a 2g. I've thought about a port and polish for sure. Any recommendations on valve springs and retainers? I know the 272 camshafts seems to be a very popular route to go and I've been looking into that.
 
It's a 98 GS-T, so it's a 2g. I've thought about a port and polish for sure. Any recommendations on valve springs and retainers? I know the 272 camshafts seems to be a very popular route to go and I've been looking into that.

Cam recommendations are going to depend on your spring choice. If you plan on running stock springs, stick with a cam that has better duration, but close to stock lift. It's also going to depend on where you are looking to make power, and what turbo you are running. There isn't going to be much of a point to running cams with a turbo that chokes above 6500.

Yes, 272's, 264's, and even a 264/272 combo are all likely to pretty good choices, but again, we will need more information about what exactly you will be running, and how you are going to be looking to make power, is top end power that you will only use at the track what you are looking for, or do you want something where the power is skewed towards the mid-range and usable in a DD?

If you plan on going with springs, the Kiggly's Beehive springs are going to be the best available, but total overkill for your power goals. It would be pretty hard to go wrong as long as you pick a good brand here though. My recommendation would probably be the Manley's, but I have heard good things about the BC springs as well.
 
I will mainly be using the car for an aggressive daily, I have another daily truck so being setup like this will be fine, and an occasional auto x and road course setup. I am researching into building the engine for being able to hold the power efficiently for a long time. I plan on changing out to at least a 16G as that turbo will def produce the power I am wanting and maybe beyond a bit. I would love for the power delivery to be in the lower mid range and a bit above. I hope this info is what you were asking.
 
I will mainly be using the car for an aggressive daily, I have another daily truck so being setup like this will be fine, and an occasional auto x and road course setup. I am researching into building the engine for being able to hold the power efficiently for a long time. I plan on changing out to at least a 16G as that turbo will def produce the power I am wanting and maybe beyond a bit. I would love for the power delivery to be in the lower mid range and a bit above. I hope this info is what you were asking.


Yes, that is what I was asking.


A few things we need to cover first though:


1. A good condition stock 4g63 will handle 400 hp reliably on a good tune, you don't need a built motor to hit this goal.


2. A 16g almost assuredly is not going to net you 400hp.


If you are looking for low-mid range power, it's important to note that cams will typically have the opposite effect. Going with 272 cams will surely cost you some low-mid power loss. With that said, I currently have the BC 272's, although when they came, they were actually a 268/272 combo, I definitely lost some mid-range, but gained a ton up ton, and after a few days, I didn't even notice the admittedly small mid-range decrease anymore.


If you are set on hitting 400hp, and you want to do it with a bolt on turbo, I'd suggest the 68hta as an alternative to the 16g, FP even still has them on sale.


I believe I logged ~41 lbs/min on my Evo 3 last year, that's approaching the end of its efficiency, you're not really going to be able to push a 16g much beyond that, and I was nowhere near 400hp.


I'm not saying that it can't be done, it has, I'm just saying that it's not really the most cost and/or time effective way to reach your goal.


I'll be honest a 400hp DSM is probably considerably faster than you expect. Last year, mine went 12.7@108, and like I said, it was nowhere near 400hp. If you really want a fun, but fast street car that you can do some racing in from time to time, I'd consider revisiting that power goal, and perhaps setting something closer to 325-350 as the goal. An Evo 16g @ 30psi is fun as hell on the street.


I have a feeling that if you build a 400hp FWD DSM, you're going to realize that it is way more than what you originally intended.
 
Yes, that is what I was asking.

I'll be honest a 400hp DSM is probably considerably faster than you expect. Last year, mine went 12.7@108, and like I said, it was nowhere near 400hp. If you really want a fun, but fast street car that you can do some racing in from time to time, I'd consider revisiting that power goal, and perhaps setting something closer to 325-350 as the goal. An Evo 16g @ 30psi is fun as hell on the street.

I have a feeling that if you build a 400hp FWD DSM, you're going to realize that it is way more than what you originally intended.

Totally agree here. The difference between a stock 2G and even a 300 whp 2G is pretty huge. Last time I dyno'd my car (6.5 years ago) it made 376 whp and 349 torque, and my fastest trap speed was 119. I couldn't get a good launch out of it, but if the car hit 119 then I probably could have run an 11.99 ET with a good launch. I blew the engine shortly after that, trying to squeeze another 24 whp power out of it. While the stock engine CAN handle 400 horse, any fuel delivery glitches or tuning mistakes can have catastrophic consequences when they occur at such high power levels.

I would also suggest setting a 325-350 horsepower goal and make gradual, slow steady progress toward it by making informed decisions. It is cheaper and requires less time for research and labor to hit that goal. It'll be more enjoyable to drive on the street, easier (and safer!) to tune, and won't be pushing the limits of any stock hardware.
 
Ok, so if you guys are suggesting a drop in HP goal what all would I need to do to efficiently and "reliably" reach and maintain that goal? I want my engine to be as efficient as possible whether that be through quality parts, porting & polishing, etc.. I'm open to any and all suggestions. I'm currently delving into suspension as well as I literally havve to replace all coils and brakes on the car.
 
Ok, so if you guys are suggesting a drop in HP goal what all would I need to do to efficiently and "reliably" reach and maintain that goal? I want my engine to be as efficient as possible whether that be through quality parts, porting & polishing, etc.. I'm open to any and all suggestions. I'm currently delving into suspension as well as I literally havve to replace all coils and brakes on the car.

This is really a question that has been answered a billion times before, you'd be better off searching and reading all the other threads that exist on the subject.

The short answer though is that the important things to making power reliably:

1. Maintenance - You want to know the engine is in good condition and without any issues.
2. ECMLink - You're going to need a way to adjust all of these changes you will be making, and to see what is going on.
3. Fuel Delivery - You want to make sure that you can deliver the amount of fuel for the air you will be moving.
4. Air - You want to know that the engine can breath in and get rid of as much air as it needs to at any given time.

Beyond that, everything is going to be choices that you will have to make based on your own setup, based on the research that you do.
 
Preface: When I was a teenager my old biker-dad once told me: "Chrome don't get ya home." These are words to live by.
You have a daily driver truck which helps out a ton, but in general: If your DSM is your primary means of going to work, school, family, and social functions, then focus on the things that keep the car roadworthy before ANY other modifications are done. Sounds like you are on the right track there, with getting your suspension R&R'd.

Once your DSM is fully reliable as a stock vehicle, and you have some $$ burning a hole in your pocket, then:
This is only an approximation (not a suggestion)... but if I was to start over with a fresh stock FWD 2G and wanted a reliable ~300-350 whp build that is fun and comfortable to drive, my shopping list might include (but not be limited to):

  • Rebuilt head with stock valves, upgraded springs & retainers.
  • A mild camshaft upgrade, like 264/264.
  • ARP head studs (the cheaper ones, not L19s).
  • Cometic viton-coated head gasket.
  • Turbo:
    • ~300 horse: Big T28 turbocharger (genuine, not the $300 eBay junk). These are still available for a limited time from ExtremePSI.com and right now are on sale. Forced Performance can still upgrade a T25 to a Big T28 if your turbine housing isn't cracked, but the T28 is permanently discontinued by the manufacturer. Last I checked, FP's price to upgrade a T25 is more than a whole new on-sale unit from Extreme PSI.
      • Genuine T28 rebuild kit (just in case you need it in the future, if you can find one they are cheap - call Forced Performance and see if they'll sell you one).
    • ~350 horse: Evo3 16g (genuine, not eBay).
  • An E85 compatible drop-in fuel pump, and "fuel pump rewire" mod.
  • Adjustable fuel pressure regulator
  • ~880cc/min fuel injectors
  • ECMLink v2
  • Evo8 MAF (MD336399) or the cheaper-but-similar 3.8L MAF (MD336482) and Injen (or similar) intake pipe. The 399/482 MAF sensors are round, not oval like a DSM MAF, but are easily adaptable.
  • 1G blowoff valve and 2G adapter.
  • Tokico Illumina 5-way adjustable shocks, stock springs.
  • Transmission:
    • If 5-speed, then ACT 2100 "Street" clutch kit (but use an OEM throwout bearing).
      • A limited slip front diff of some kind. There are a few "cheaper" options for LSD, while the better options are quite expensive.
    • If automatic, then a custom EPROM re-flash and IPT upgrades as budget allows.
As you can see, the more you start modding the more other mods you have to do to keep the overall system happy and balanced. Things get really expensive really quickly. Take your time, be realistic, and do your best to understand how all the different components work together and react to changes.
 
Last edited:
Dapperz, you should be fine with stock valves - they are quite tough really. If you plan on upgrading camshafts beyond the typical 264/264 setup, or plan to rev past 7500, it would be a good insurance policy to upgrade your valve springs too. Upgrading springs as part of the rebuild will save time and money down the road, but of course it does add to the cost. I've heard bad things over the years about Brian Crower springs... for example: http://www.dsmtuners.com/threads/bc-spring-broke-in-half-and-destroyed-head.360359/

This is Dustin from BC and i just stumbled across the post. That thread from Kelvin - something did happen to his head and it was unclear what broke the valve spring but we replaced everything for him and have been working with him for years since then. His entire engine is BC. Anyway if there is anything i can do to change your opinion of us please don't hesitate to contact me direct at 619-749-9018 ext 101 or email me at [email protected]. PAC RACING in michigan makes all of the BC springs
If you had any issue with us let me know how to fix it.
 
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