conflicting information about 20v on 16v block

[hillclimb86]

after my last post i thought i would take the risk and go a head with the 20v haed on 16v 3 rib block but after speaking to a few people who have worked on twin cams i have new problems.
do all the oil galleries match up on 3rib block and 20v head i have put 20v head gasket on the block and looks right every thing lines up,
i have also been told quite strongly that 16v pistons will clash with the valves no questions asked. if i use 20v pistons on my block will it work or am i wasting my time or do what matty sugessted and use a small port head and put quads on any ideas
are 3 rib blocks strong enough to handle higher power there are so manny differnet opinions on there strength

thanks

[pumpkinking]

i have this engine in my car and so does my friend..

where you from? if Sydney 'll put you in contact with the right people

[hillclimb86]

im in sydney ryde area

[Dxaqta]

i have this engine in my car and so does my friend..

where you from? if Sydney 'll put you in contact with the right people[/b]

beau u have a 20v block with 16v head

me thinks if ur going to the trobule of using a 20v head u should use a 20v block as th head is the harder part in the conversion ie converting to rwd, plumbing problems, dizzy and so on

and seriously dont waste ur time with a 3 rib block there is so much better out there... that is the oldest of all the 4age blocks

[mc68]

bt if your on a budget, then its not like u cant get reliable horsepower out of them....sre 7 rib is far superior...but if your a kid with a jdm bigport, and want to put some higher lift cams in it, then it wont hurt it in anyway.

[rthy]

why cant you get reliable power out of them?

[mattysshop]

your problem is that your using a 3 rib block.. ergo 40mm bigends, and 18mm gudgeon pins.

the combo you want for a 16v bottom end conversion is the 7 rib bottom end.. 42mm big ends and 20mm gudgeon pins which are the same as 20v's so you can slap a set of 20v pistons onto a 7rib bottom end no fuss.. but you cant with a 3 rib block unless you use the 7 rib crank and rods if you get my drift..

unless you can get a 7rib bottom end and 20v pistons.. sell the 20v head and use a smallport 16v head, if you want a little bit extra out of them, use bigport cams.. difference is marginal.. but i've heard of some people getting a few hp here and there. (like 4-5hp)

[hillclimb86]

when i bought my head i got the whole engine and throttle bodies so if i use the crank and rods out of that and get oversize pistons as my 3 rib has 40 thou oversize pistons in it will that work. if that doesnt work ill sell the 20v minus the trottles and get a small port head and do similar to what you did i guess as it works pretty good a .Do you know whats wrong with the 3 rib cause i spent the money getting the 3 rib machined so i want to use it.

[mattysshop]

the block itself can't put up with as much abuse as a 7 rib block.. cut your losses.. i have said it many times.. for 20v head.. you need 20v pistons.. they have 5 fly cuts in the pistons.. are they just some casties? 1mm o/s cast pistons? you should be able to sell that block no worries.. you will need to get 40thou o/s 20v pistons if you really want to use the 3 rib block.. use the 20v block.. you are not gaining anything by using the 3 rib block.. even if it has been machined etc etc..

the oilpump in the 7 rib blocks is significantly better than the 3 rib block..

and the 7 rib block has oil squirters pointing up into the bore to spray oil under the piston.

[jjoeworks]

I don't want to confuse you at all with regards to the 7 rib vs 3 rib debate. It makes sence that the 7 rib is stronger and nobody is arguing that but it is a misconseption that the 3 rib is weak. When I was researching the type of engine I wanted for my application i wanted a high reving reliable bottom end that would be O/K for around 900RPM. I wanted the lighter 3 rib 40mm crank and lighter 18mm rods (read Bill Sherwoods modified 4AGE site) and I had a 3 rib block lying around so I used it. I went for Weisco 10.5:1 forged pistons and it has remained extremly reliable and produces reasonable horsepower. It has been regularly reved to 9000RPM with no problems at all ever. You have to ask yourself the question "When was the last time you saw a 3 rib 4AGE block fail". I don't think I have ever and i have been playing with them for a while.
If I were you I would stick with the block that is machined up already and enjoy. It all comes down to a budget and how much you have to spend. If you were going to go forced induction and high boost well that is a different story. Thats is my 2 cents worth.

[hillclimb86]

big port head going on 3 rib block in next few days and up for sale cost me 2,500. then 20v head is being polished and new cams plus few other things dont know exactly what. bottom end getting stripped and rebuilt with new pistons then, reroute water, coil packs , a haltec comp a good tune and should be done hopefully know engine troulbes for a long time tahnks for imput peoples much appreciated