DUAL OVERHEADHEAD CONVERSION IS IT POSSIBLE

[bluedemonprelude]

TO EVERYONE

IS IT POSSIBLE TO COVERT TO A DIFFERENT HEAD THAT IS DUAL OVERHEAD AND INSTALL IT ON A 87 PRELUDE 2.0 SI? IS THERE AND EXISTING CONVERSION HEAD MADE JUST FOR THAT 0R IS THERE A HEAD THAT CAN BE BOLTED ON? PLEASE DO RESEARCH AND GIVE ME ALL THE ADVISE THAT YOU CAN. I THINK IT WOULD BE KINDA COOL TO DO THAT AND BEEF UP THE ENGINE THAT I HAVE. THANKS FOR ALL YOUR IMPUT.

STEVO

[CleanGSR]

Honda DOHC heads will not bolt up to a single cam block. You'll have to swap motors to get DOHC.

[James Matteu]

Honda DOHC heads will not bolt up to a single cam block. You'll have to swap motors to get DOHC.

A Twin Cam head from a 1987 Acura Integra (D16A1) will bolt onto a 1987 CRX Si (D15A3).

 

I have never owned a Prelude, so I dunno where the donor head would come from.

[James Matteu]

In my opinion, you are barking up the wrong tree. You need to get your powerplant from something made in the 90's.

[CleanGSR]

A Twin Cam head from a 1987 Acura Integra (D16A1) will bolt onto a 1987 CRX Si (D15A3).

 

I have never owned a Prelude, so I dunno where the donor head would come from.

 

My mistake then.....it must be one of the only motors where this is possible with honda then, cause the newer stuff won't.

[James Matteu]

This may be new to you, but your A20A has more in common with the ET engines of the early eighties and late seventies than it does with the B-series that replaced it.

 

Unfortunately, all A-series motors came in SOHC with either PGM-Fi (partial OBD-0) or CVCC.

 

There have been twin cam B-series swaps onto A-series motors, but I have yet to hear of one that would run properly.

 

There is still good news, the EZ, ES, BS, and ET engines had their hayday on the SCCA tracks all over America, and the technology should translate over to your motor easily.

 

You could go with carbs: either twin side carbs or custom intake manifold for a 4 carb setup. Send your cams off to JG Engine Dynamics to get your motor tuned to rev extremely high. Increase oil and fuel delivery and your set. Talk to some old 4-cylinder Ford Mustang guys and they would be able to help you create a turbo box for the carbs.

 

You could upgrade to OBD-1 and boost the A20A you have. Since it is an iron block, it should be easier to reinforce than it's alluminum B-series brethrin.

 

 

This may be a hard pill to swallow, but unless you are prepared to construct a custom DOHC head from a billet of alluminum, or go the few other options you have with the A-series; you might want to consider a full swap.

 

The closest I can find to swap info is how nobody seems to have tried swapping a DOHC head from a JDM 1987 Prelude 2.0Si (B20), given the motor is so hard to come by. If I had a JDM B20, I would think the motor is worth more in one piece rather than swapping the head over to a run of the mill A20A.

[CA3B20A3G]

If this is a 2nd gen Prelude, then no DOHC heads will fit onto the A18/A20 blocks. However you can get a B20A from a 3g accord/2g prelude (gold top from the prelude, gold & black top from the accord) which would bolt right in. finding manual gearboxes are a bit hard though.

You could also buy a set of Place Racing engine mounts (out of production, but are still around for sale) & drop a B-series in there, with a few other modifications it will be running

 

if it's a 3rd gen Prelude, then i would assume it has a B20A3, which you can swap the head for a B20A5 (DOHC) then you would have to convert to fuel injected

[James Matteu]

However you can get a B20A from a 3g accord/2g prelude (gold top from the prelude, gold & black top from the accord) which would bolt right in.

In the US, 3G Accords and 2G Preludes did not come with a B20A. Your right though, that motor would bolt right in. Stateside, his best bet is to upgrade to OBD-1 and drop in something newer, something B-series.

[88prelude]

In my opinion, you are barking up the wrong tree. You need to get your powerplant from something made in the 90's.

 

 

 

haha ive owned one car from the 90's ( a mitcrapbishi eclipse) and it was THE WORST CAR I HAVE EVER OWNED..im stickin with 80's cars til they all disappear

[Hatch92]

^ must have been the 1.8L SOHC Eclipse then. The 1G 4g63 Elcipse is mean, especially AWD..... ooo launchs sooo hard.

[James Matteu]

Holy dusty dead thread batman!

[BrIaN EG2]

^ must have been the 1.8L SOHC Eclipse then. The 1G 4g63 Elcipse is mean, especially AWD..... ooo launchs sooo hard.

very true, 4G's are great engines.. friend of mine had a 1G talon TSi AWD, that car was crazy quick until some stupid mom hit him in her minivan >_<

 

Holy dusty dead thread batman!

^^ LMAO

[Hatch92]

i want a 1g or a 2g next, i prefer 2g 7-bolt FTW

[BrIaN EG2]

i like the 2bGen talon TSi or eclispse GSX AWD, they are mad sexy

 

plus theyre light too

[88prelude]

^ must have been the 1.8L SOHC Eclipse then. The 1G 4g63 Elcipse is mean, especially AWD..... ooo launchs sooo hard.

 

 

i had the 1st gen 2.0 DOHC non turbo and i put oveer 2g's onto the motor and all it did was break down every week thats why im stickin to honda forever lol

[Hatch92]

see that was the problem it was a non-boosted 6-bolt.

[lastresort576]

the 7-bolts are more prone to crank walk than the 6-bolts...then again they both walk.

[Hatch92]

^ negative thats why the 96+ 4G63 was made a 7bolt. it was to help with stength leading to less crankwalk. however get on any DSM website and it's a common debate which is better. i have seen more 6-bolts crank walk than 7-bolts.

[88prelude]

what is the difference between 6 and 7 bolt and what is crank walk?

[Kastigir]

^ negative thats why the 96+ 4G63 was made a 7bolt. it was to help with stength leading to less crankwalk. however get on any DSM website and it's a common debate which is better. i have seen more 6-bolts crank walk than 7-bolts.

Incorrect. The 7 bolts walk more because many of the crankshafts were machined out of spec. Instead of fixing this glaring oversight, Mitsubishi used them as-is. Some of them are fine with their bearings, and others move to much causing excessive wear and eventually...crankwalk. There should've been a TSB, and then a recall but Mitsubishi denies any wrongdoing. 90-94 have virtually zero crankwalk. 95&96 have the most cases of crankwalk, because that's when the bad run of cranks were made. In 97-99, Mitsubishi realized their error, and fixed it. They have less walk than the 95/96, but more than the 90-94s.

[Kastigir]

what is the difference between 6 and 7 bolt and what is crank walk?

The number of bolts holding the flywheel to the crank. Crank walk is when the crank has excessive movement inside the crankcase. This is caused by cranks machined out of spec, and not fitting correctly in their journal bearings. When the play becomes too much, the crank moves or "walks". Many things can happen, most notably is the crank moves enough, so the crank begins hitting the CPS trigger plate. There are color codes somewhere on the crank, that you can give to Mitsubishi so they can supply you with the correct journal bearings. Like I said, Mitsubishi is aware of the problem, yet they still...to this day, deny any wrongdoing.

[alex37211]

haha ive owned one car from the 90's ( a mitcrapbishi eclipse) and it was THE WORST CAR I HAVE EVER OWNED..im stickin with 80's cars til they all disappear

 

 

well there's your problem! Mitsubishi sucks. Try a 92-00 civic or 94-01 integra the next time you consider a "90's car".

[Hatch92]

Incorrect. The 7 bolts walk more because many of the crankshafts were machined out of spec. Instead of fixing this glaring oversight, Mitsubishi used them as-is. Some of them are fine with their bearings, and others move to much causing excessive wear and eventually...crankwalk. There should've been a TSB, and then a recall but Mitsubishi denies any wrongdoing. 90-94 have virtually zero crankwalk. 95&96 have the most cases of crankwalk, because that's when the bad run of cranks were made. In 97-99, Mitsubishi realized their error, and fixed it. They have less walk than the 95/96, but more than the 90-94s.

 

only problem with that is the alot of people rely more on the 7-bolt than the 6-bolt. as for the 96-99 having more crank walk than 90-94's i don't know about that. i have personally rebuilt more 1g 4g63's that 2g's. Most of the time the 2gs were beat on more than the 1g's and had no signs of walk at all. Like i said if you get on any DSM forum this is a common argument so lets just end it here and move it to the crank walk thread, because i know this is gonna continue.

[Kastigir]

only problem with that is the alot of people rely more on the 7-bolt than the 6-bolt. as for the 96-99 having more crank walk than 90-94's i don't know about that. i have personally rebuilt more 1g 4g63's that 2g's. Most of the time the 2gs were beat on more than the 1g's and had no signs of walk at all. Like i said if you get on any DSM forum this is a common argument so lets just end it here and move it to the crank walk thread, because i know this is gonna continue.

No it won't, because you're wrong. I own one. I've read about them. I've been to many a DSM forum, and they back up what I said.

[lastresort576]

yea i was basing my reasoning off of what ive been told/read. alot of the car scene in my area is eclipse's and srt4's. i also looked into it a lil bit, thought about getting one. and i believe there was another reason as well for the 7's having more walk.

 

a local 2g ('97)thats tits. from what the guy said to the best of his knowledge from the forums, its 1 of 7 converted gsx-spyders with a 6-bolt. If you want i can copy the build list here as well, since the sites link is protected.

This engine pic is actually kinda dirty compared to how he keeps it. There isnt a spot on it, no lie!