what should i expect?

[edakotaford]

hah... i am really dumb. i just realized that the A87 was the stock head on my L18. and i thought i had gold. hahaha. i do also have a U67, and according to the620.com the a87 has 1.25 intake ports, where as the U67 has 1.375. my senses tell me that i may have a slight power increase from better airflow, would this be logical? the u67 does have square ports though, so maybe that would hinder my hypothesis? either way, i just want to get the most out of this engine. how much would it typically cost to get my block bored .2 over? and are there any machine shops around puget sound area that do it? also about the head, what good what a port and polish do for me? i want this thing running like a champ. but i don't want to dump a billion dollors into it when i could just go KA or VG...

[datzenmike]

If the A-87 were used on an L20B with larger displacement, the smaller intake runner cross section will force air flow to speed up which will benifit cylinder filling, but only at mid range speeds. As revs climb this smaller port will be too small for the needed flow now required, and act as a choke point, hindering the breathing. The U67 is a better match with its larger ports and will breath better ar higher RPMs and produce more power for the L20B.

 

A U67 head on an L18 will lower air speed due to the smaller displacement and larger ports. Low intake velocity does not benifite cylinder filling at low speeds. The U-67 would be a good choice for upper RPM power on an L18.

 

In a perfect world the intake runner would be variable in diameter... smaller at low revs and increasing in size as the RPMs go up for good breathing.

[edakotaford]

hah, yeah, too bad there isn't vtec in L engines... that would be freaking fantastic. i guess i'm just going to have to figure what i want and need. if i'm going to race it around with the U67, and be in high rpms the whole time i'm going to face losing all gas milage and running my engine into the ground. with the A87 i'll have maybe a little power at the start, but i'll be choking my engine... a better tranny may ease my power starvation... at least for a little bit. what about boring? what do you think of that?

[datzenmike]

Didn't want to mislead you. There won't be a night and day difference. Both heads will work fine on an L18, period. The larger port U-67 would have a slight edge when revved up specially with a larger cam. The same cam in the A-87 would be slightly less so. If you plan some performance improvements in the future then the U-67 might be a better choice overall. If you are just going to drive it, either would be fine. By any chance is the A-87 a closed or P-nut chamber???

[edakotaford]

you know, i was told it was a peanut, but i haven't pulled it to know for sure. what kind of "performance mod's" are you referring to? what really is there that i can do to my engine to make it decently quick before i toss it in the car?

[datsunfish]

I ran a w58(same initial port size as the u67 but tapers in on the sides,also round port exh. with liners) open chamber on a L18 and it revved up like crazy.Killer top end power with crappy gas mileage.I now run a super small 210 head on a l18 and have super low end power with terrific gas mileage(30+)and it chokes out at about 5K.

It is fun to scream around with the whole powerband available though.I have a w58 peanut head which I believe is the only stock large port l20b peanut.It screamed on the l20b with great power range and good gas mileage.

Not wanting to dump $$$ into it means you need to make the best of what is available.You also need to know where you want to compromise.Top end,low/mid or $$$.Port out a stock l16 manifold to 1.5 and port match the head.Run a weber 32/36 carb and open the exhaust to 2" and you are golden.

[Cuts metal like mad]

for machine work... buds machine shop is highly praised. However, a ka24e is cheap and makes about 140hp stock with decent tq as well... you'd quite a bit more to get the l18 to those levels and keep the mileage and driveability. The ka is based on the L-series as well... ;)

[racerx]

I, too, have an L18 and there are 2 types of heads for this set-up (open and closed). The L series set-up is ol skool and it really depends on your finances and your capabilities to get more HP for these engines. That's why a lot of people just toss them and install a KA or SR motor. The other thing you have to remember is when you up your HP, you will have to consider suspension, brakes and fabrication which escalates in cost and time spent.

 

Again it all depends what you want to do. A stock L series engine, your lucky to get 100 HP..this is with 32/36 weber, headers, smog disconnected and so on, hi-po intake. Figure a new 32/36 is about $300, headers about $200..so that's already $500 and not sure what a hi-po intake will set you back. Now you can purchase these things used but I don't like buying carbs used or even headers (leakage)...

 

That's why I will leave mine stock besides 32/36 weber and pointless system. remember, there's always going to be someone faster and I would like to keep mine as a daily driver and easy to work on.