well, it looks like i'll have to take off my 2.0 heads to inspect for a bad valve seat. i need to repair the spark plug threads anyways, i've just been putting it off. any advice/tips when rebuilding air cooled heads? how many parts can i reuse, and are there anyways to tell if valves, springs or other parts are bad? should i just replace most of the stuff as long as i have the heads off? thanks!!!

As long as you have them off it is a good idea to do a complete refurbish. Might be able to get away with reusing stuff, but its not worth the risk in my opinion.

my 2.0 had a valve seat that was pounding it's way back into the head, so I had to rebuild them. Here is my suggestion, and what I did. First off, heli-coil ALL the threads for spark plugs, if they are not already done. Next, fix the cracks in the heads. I have yet to see a 2.0 head that has any miles to speak of on it without at least some hairline cracks. They can be welded up, and polished down. Then, replace any seat that looks at all suspicious. You will find that the intakes seem to pound in more often. Strange huh? I replaced all my valves, because they didn't have the nice sharp angles that I felt should be there for a quality seal. Valve guides are cheap, and don't last forever, replace all of them. The springs are probably fine, but they arne' that expensive, especially the heavy duty ones from pelican. That's what I bought. Plus, if they bust bad things happen. Of course you want new keepers too. As for the type of valves you replace them with... that is a matter of much debate. I am a firm believer in the original sodium filled exhaust valves. Some people say they are a waste of money, but in my opinion, they are worth it. Sodium filled valves have sodium injected inside the head/lower stem. WHen it heats up it sloshes around promoting cooling. There are people who strongly disagree though. So, I don't think you can screw this choice up too bad. One word of caution would be to have someone do the work with air cooled experience. Our valve stems have abnormally high amounts of clearance, because they heat up more than a watercooler, among other little differences. Good luck.

Tony

I am going headless, I refuse to replace anything I can't see... I am a cat... I bend like a reed in the wind.... no man shall pass....

I just ate, can we talk about something else... like rust..

uhoh..


m

miles you are being bad again dont make me send teri over

thanks guys! just what i was looking for. time to drop my motor i guess...

Sodium filled valves are not the answer. They cost too much and don't do their job!

I have seen more failures that cost complete engines to be destroyed from sodium filled valves than all others 3 times over.

Send your heads here
www.haminc.biz

Then its a done deal..

Let a pro who does aircooled heads do the job.

You wouldn't believe some of the fuched up head work I've seen.

Yep, but not all them know the TIV head well either....

I have found TWO people that can do them right in my lifetime!

Jake,
Who else do you trust to do 914 head work besides Len ?
Thanks,
Dominic

Jake,

I know you do this for a living, but a type 4 head isn't rocket science. There are "tricks", but if you are just doing a stock rebuild, there are many good people who can be trusted. I used a place in spokane washington call cylinder head service, and they do everyting from bug's to flat head v'8s. They did an outstanding job, and for less than rimco. Time will tell I guess, but the first 30,000 miles have gone without a hitch, as I expect the next 30k to go as well. Just make sure you use someone with some experience in this field, that's all. It's not as if he is looking to bump the size of valves, or do port work.

I agree with mark and silver 2.0.

1st, let a professional do it.

2nd, There are many people who can do a stock head, or even race heads. We have a guy locally who has been doing warranty repair for the Porsche dealership for 30 years. He's done 8 sets of heads for me with no errors yet.

Silver 2.0 I disagree 100%.

Experience with the Type IV head is a necessity to do this job correctly. The stock head had flaws right from the factory that create hurdles for any head technician to overcome. These issues if not noted and taken care of will create the same issues that have plagued this engine from the beginning of time.

The major problem with the stock head from the factory was valve seat material, and interferance fit of those seats. The stock material was a sintered composition that shrinks when its over heated. Couple that with lack of interferance fit on an aluminum head and the expansion that the head goes through and voila you have a dropped seat.

Type IV specialist that were dedicated to the development of these heads had to try different types of steels and fits to find the perfect mix of interferance and material. This is why they never talk about the procedures or the seats. These seats are also harder and resist being pounded out over miles, but not too hard to mar and pound a stainless valve.... Think some Chevy technician knows that?? Wrong..

Materials also go much deeper than just the valve seats! A good for instance is the valve guides. The stockers sucked, the stock replacements suck too. The most expensive ones on the market also suck and start wearing in 5,000 miles! The best guide is one thats NOT EVEN MADE FOR THIS ENGINE! and they cost 1/2 of what the expensive ones cost and won't wear! Hell they even tear up reamers they are so tough, BUT they are soft enough not to tear up the valves or gall!

The other part of experience comes from using bad judgement and suffering failures. When a mistake is made and a failure is a result one soon finds the issue and does not repeat it. This is SO VERY true with the Type IV head since all its development with strength have came from trial and error....

Unless you specifically deal with these heads you may never know just how deep you can flycut a head before you hit the areas that are known for have core shift in the castings. Not taking the care in this area might just blow a hole right through the chamber (I have done this)

also there are areas that also may be more crack prone that only show up when the head is heated and lookied at by a trained eye that has had to foot the bill on a repaired head after a crack wasn't found the first time around, when it should have been. These little thiongs make you guys have a few hassles, but they cost us food off of our tables- literally!

The last portion is tooling. Good machinist mae fixturing and cutters for everything. Having a good type IV head tech do your heads is a benefit because he knows these tools and knows their capabilities and the specific job they were made for.

The Type IV head is the most scientific head I have ever been around. This includes aircraft engines, and everything from aircooled Deutz Allis tractors to old flat head Fords, right on up to Mercedes and BMW heads. Finding someone that does all sorts of heads and having him do your type IV head work is just like stabbing yourself in the back.

Find someone dedicated to these headswith the known seat materials, a known welding technique for the castings and pay him your money.

If anyone else does the work, and it breaks, has blow by from worn guides, or fails a leakdown test in 500 miles because the valves/seats are pounded out don't come asking for help!

And the answer is YES, this does pertain to 100% stock engines just as much as performance, because stock engines run even hotter than most big engines and soak up much more of their energy just to move the car!!

Would you go to a general physician to have heart surgery???? Thats exactly the reason why no one should touch those heads other than the Type IV head specialist. and... Don't go screamin about costs! when you have to do the job 3 times before its done right its more expensive than doing it the right way the first time!

I'm hard to please, but we have not had a cylinder head related failure since 1996 and that includes street and RACE engines, and over 500 of them!

well, just got finished doing some pricing on the PP web site. valves arent cheap. i can afford to replace everything except the valves, at least at the moment. i could afford to replace a couple of the really bad valves, but not all of them. how can i tell which valve are in need of immediate replacement? rounded edges? bent ones obviously. anything else?

Replace ALL exhaust valves...Don't use Sodium filled!

ok to reuse intake valves if they don't look too bad? those sodium filled ones are 60bucks a pop anyways! don't they know that i'm a poor-ass!

The sodiums are a waste of money..

The intake valves can be reground at any machine shop for 2 bucks each and they can also recut your seats for you cheap as well.

Exhaust valves don't play- They kill engines everyday. They are silent as a mouse and snap all of a sudden and cause catastrophic wallet draining splatters!

who's a good supplier of type IV valves? i've search around a little, but all i can find is sodium filled valves on PP or performance products.

JAKE...you put a link of haminc---does not show up on the web, can you clarify what the objective price will be for a rebuild?????

Here is the link that I think Jake was referring to, but I didn't see any prices, prolly have to contact them directly.

Hoffman Automotive Machine, Inc

Anyone know a good head shop in Oregon, prolly Eugene I'm thinking. Don't really want to send my heads cross country if I don't have to.

Right on with the link to hoffman--prices are not toooo bad, but, I want to only have to do this every 200k--so I guess money well spent. Did I mention there is a price list on this site? Took some navigating, but I eventually found it..

Every 200,000 miles!! What do you think this is a Nissan? Well, Jake, you are certainly "strongly" against the sodium valves, and I knew that before I posted. But believe it or not, sometimes various opinions are a good thing. You offer good advice, but sometimes I think you take yourself a little too serious.

anybody know a good source for 914 valve train parts other than pelican or performance products?

Hell yaeh man---pushing 300k on my 1.7 right now. I still spin it to 6k everyday---keeps the cobwebs out. And yes it leaks, yes it burns oil, yes it has a LOT of blowby, but it has never let me down, gets 43 MPG in supercruise mode (72 mph) and that is with dual 40's, an ancient large tube header, 009 set to 56 degress total ( did I mention it has a LOT of blowby) and a Mallory 60k sparky thingy,,,,oh----and I switched to bosch twin electrode platinums

Those plugs made a tremendous improvement in idle quality!!!! I then tried the four prong ones and it ran worse than with the autolites, back to the twins!!!

I take myself very serious, and thats really because I have had the opportunity to be trained BY these engines. I do the best at what i can and this stuff is always on my mind- constantly. The last thing I think about when I go to bed is a Type IV engine, and the first thing when I wake up is also a Type IV engine.

The heads are the least forgiving part of these engines, but ALWAYS the most overlooked and cheaped out on! when you have a head issue the killer is a silent stalker, much like a Sniper. You will never know he is present till you hear that "BANG" out back and pull to the side of the road! I take heads so seriously that sometimes spend a day of cleaning them up just before sending them out to Len just to make sure the cores are worth working with-

I have had many more opportunities than most people to be schooled by these engines and tell me what they want, and what they like and I then effectively trick them into doing it better.

This is the only way my development has been so effective! i discourage those sodium filled valves for many reasons and have not used ONE since 1995, and since we have not had a single valve related engine failure- not one. I can't say that for some of the cores that we receive, more than 25% of them are killed by those sodium filled valves. when they decide to let go, they explode and take the piston and case with them in most cases..

back to taking things seriously- This is my job and my life. The problem today is that few people give a damn and they treat their job like its just anything- no big deal....Thats why companies are moving overseas, because our workforce lacks attention to detail and always wants more friggin money to be slackers anyway!

The day don't take this seriously, I'll be laying flat on my back surrounded with flowers at my own funeral. Until then I'll guarantee you that there will not be a more dedicated soul to promote the development and usage of this engine- HELL yes I'm serious! Think I'm serious here, you should TRY to work for me!

Yeah Jake I can't imagine that you would be a laid back boss

So your saying that while I have the heads off the 2.0 I have I shouldn't just clean 'em up and slap them back on? Already know your answer to that one, just trying to stay in a budget.

I do have another question, I have been told and read that I should not replace the gaskets between the cylinders and block or the ones between the head and the cylinder. Can you tell me why?

I didn't say that you take your work too seriously, I said you take yourself too seriously. Big difference.

Not really- Because work IS my life.

Same problem with the Ferrari 308 engine.....no one uses sodium valves when rebuilding these (you think a Raby engine is expensive try pricing a Ferrari rebuild!!).

They break at the stem where it narrows down just before the valve itself. People have taken a perfectly good looking used exhaust valve out of a 308, tapped it against a hard surface and had it break in half.......

so sodium filled sucks. too bad i can't find anyone selling regular old valves for the type 4. maybe i just dont know where to look.

google 914 exhaust valves

It's not the sodium that is the problem, it's the engineering/manufacturing. There are many modern engines still utilizing this technology. It's not the sodium's fault that there is not enough meat at the stem. Maybe there is manufacuring defects, or just poor engineering to begin with involving this type four engine and the sodium valve, although not all of them fail, or will fail. Subaru still uses this for their valves, inculding their 2.5 liter 300hp sti.

European Racing if you have to order on-line...I got my stainless steel valves from them.....




I think the failures are from re-using old valves....also, the enviorment of an old air-cooled engine is different than a modern water-cooled one....

if the factory valves had been that bad from the very beginning, the motors would not have lasted as long as they have....