blue top head blacktop bottom?

[krashdog]

I have put this engine together and it seems to have really small clearance. the engine spins but I was wondering will the valves hit and bend?


Jayson

[krashdog]

noone has done this!?!!?

we are using stock 20v pistons and a trd headgasket ... will this work??

jayson

[yoshimitsuspeed]

I'm surprised the motor even spins.

Did you use clay or wax or something to measure clearance before final assembly? That's the only way to do it and know.
If not and if it's already back together I guess your options are to run it and see what happens or take it back apart and measure.
Did you even do calculations for compression or anything?

[ga_goosh]

yes probably if your timing isnt right. the black top is the only 4age that is an interferance motor. your compression will be set up for race fuel only if you use a trd HG. i would use a thicker HG like a 1.6mm or something simmilar. misterjerk has done this but i think he used a 16v 1.2mm hg. you might have issues if you use the stock cams. look into dynamic compression and check my piston dome volume calculations to see if you will have a usable dcr. it would be quite a waste to build a motor that didnt even spin freely or ends up breaking pistons cuz of the wrong fuel.
piston dome volumes
http://www.86garage.com/forums/viewtopic.php?f=17&t=5379
compression calculator
http://www.zealautowerks.com/advanced-compression-calculator.html
dynamic compression calculator
http://www.wallaceracing.com/dynamic-cr.php
4age stock cam specs
http://www.billzilla.org/4agstock.htm

[MisterJerk]

I did this, with .8mm hg and shaved head. and it is totally an interference engine now.. to set cam timing is a little tricky, engine cannot be at 0 until the cams are set to the timing marks, then roll the crank slowly to 0. then throw on timing belt.
you will need to do something with the 20v oil pump because the tensioner is not long enough for the 16v belt. I ran an extension on mine and it was sketchy, bought an OEM highcomp/silver top oil pump, with a new tensioner and spring(you will also need the post the spring goes to) from Cabe.

dizzy timing cannot be set to stock advance either, especially with the stock ecu/injectors/fueling.
to really take advantage of the higher compression, cams and ecu would be the next logical step.

Here's what I posted in someone elses thread.

Currently I have a big port, light p&p head, shaved 0.5mm. 0.8 trd HG, stock cams. BT Pistons,rods, & crank. ae92/ST oil pump. Response is amazing, again timing is not advanced as stock due to fueling. Though i have bcpr6 plugs in it. Runs really strong. feels alot stronger than it did when i test drove the engine as a 20v. I think i screwed up the joggles when i cleaned em up some and Im going to just do some bowl work and clean up the exhaust ports on my spare stock head, and no shave.

Previously i had a stock big port head on it. felt like a super strong hicomp. but had to retard timing, due to compression and stock fueling. After installing the p&p head, the exhaust note sounded smoother and she got alot louder.

TRD 0.8 HG under both heads

Mod List:

Stock ECU and wiring harness.
Deleted EGR, electrical idle up.
20v FPR- disconnected vacuum (idled like **** with it connected)
Timing set with jumper to 5* advance.
BT 20v block with pistons, rods & crank. ae92/st style oem oil pump(16/20 with 20v oil pump and tensioner dont work. the tensioner is too short)
toda 3.7 flywheel, stock(exedy) clutch and pp.
pacesetter header.
stock cat
RS*R exmag2

it aint much, but for what i have in her she is amazing!

[MisterJerk]

http://www.zealautowerks.com/advanced-compression-calculator.html?setup=4,m81.00,m191,m77,36.00,4.7,m30.50,m122,m0.8,m0.50,7200,1500,0

i think i plugged all the numbers in correctly.

Static Comp Ratio : 13.08:1


http://www.zealautowerks.com/advanced-compression-calculator.html?setup=4,m81.00,m191,m77,36.00,4.7,m30.50,m122,m1.2,m0.0,7200,1500,0

same thing but with stock 1.2mm hg, and no cut to the head. shows more favorable static comp ratio of 11.5:1

[ga_goosh]

http://www.zealautowerks.com/advanced-compression-calculator.html?setup=4,m81.00,m191,m77,36.00,4.7,m30.50,m122,m0.8,m0.50,7200,1500,0

i think i plugged all the numbers in correctly.

Static Comp Ratio : 13.08:1


http://www.zealautowerks.com/advanced-compression-calculator.html?setup=4,m81.00,m191,m77,36.00,4.7,m30.50,m122,m1.2,m0.0,7200,1500,0

same thing but with stock 1.2mm hg, and no cut to the head. shows more favorable static comp ratio of 11.5:1

that is also a static compression and it does not change you need to find out when the intake valve closes on your cam and find out your actuall compression because your cam selection will change your dynamic comp and will affect what gas you will need.

[krashdog]

thank you all your info was a big help ..

I think I might have gotten into something I am not ready for...I was looking for a cheap build with street engine and was thinking cheap

A, because I had the block and pistons and rod bearings that are good.
B, because my blue top bottom took a spin and need rebuilding
C, max had a head for me
D, thought all this would go together like peas in a pod

F, I failed and am sending my bluetop bottom to the machine shop and build a engine the way I know...oem stock.

Thanks guys for all your info

jayson

[MisterJerk]

what happened to make you give up so easily?
It would be cheaper to throw in some OEM high comp pistons in the blacktop block, than rebuilding the bluetop bottom end.

or you could roll it like me...
Using a stock unmolested big port head, stock head gasket, you should be fine on the blacktop block, rods, & pistons, just change the oil pump to 16v and use all your bluetop accessories(water pump,alternator, PS) Use a 16v lower timing gear, crank pulley, waterpump, or your belts wont fit right.

[gotzoom?]

Max doesn't have a set of smallport pistons laying around?

[oldeskewltoy]

this is what you need to do to the cylinder head chambers to safely run higher compression

[krashdog]

what happened to make you give up so easily?
It would be cheaper to throw in some OEM high comp pistons in the blacktop block, than rebuilding the bluetop bottom end.

or you could roll it like me...
Using a stock unmolested big port head, stock head gasket, you should be fine on the blacktop block, rods, & pistons, just change the oil pump to 16v and use all your bluetop accessories(water pump,alternator, PS) Use a 16v lower timing gear, crank pulley, waterpump, or your belts wont fit right.

i am running a big port head...but it has been machined...would this be my problem. I dont know the history of the machining...it has milled

not trying to give up just confused on what to do and want to drive my car

jayson

[krashdog]

Max doesn't have a set of smallport pistons laying around?

he said I should buy new ones , but I have a baby on the way and dont have $$$$

jayson

[oldeskewltoy]

i am running a big port head...but it has been machined...would this be my problem. I dont know the history of the machining...it has milled

not trying to give up just confused on what to do and want to drive my car

jayson

Chambers can always be opened up (volume added) if done carefully(now what you are doing)....

[krashdog]

this is what you need to do to the cylinder head chambers to safely run higher compression

Im not sure what im looking at but..is that sunk in valve job or something?

jayson

[Rogue-AE95]

Im not sure what im looking at but..is that sunk in valve job or something?

OST-deshrouded combustion chambers Look at the sort of crescent shape directly above each valve seat in the first pic. It's been smoothed away.

Valve seats might also be 3-angle or sunken in slightly, that I'm not sure.

[oldeskewltoy]

this is what you need to do to the cylinder head chambers to safely run higher compression

Im not sure what im looking at but..is that sunk in valve job or something?

jayson

not a "sunk in valve job", As Rogue pointed out the chamber wall where the ridge was... isn't by the bottom view. That ridge in the chamber wall gets very hot, and will cause ping/pre-ignition. minimize that sharp edge, and the chamber can withstand considerably more compression.

Ridge, or sharp edges I speak about...

[krashdog]

this is what you need to do to the cylinder head chambers to safely run higher compression

Im not sure what im looking at but..is that sunk in valve job or something?

jayson

not a "sunk in valve job", As Rogue pointed out the chamber wall where the ridge was... isn't by the bottom view. That ridge in the chamber wall gets very hot, and will cause ping/pre-ignition. minimize that sharp edge, and the chamber can withstand considerably more compression.

Ridge, or sharp edges I speak about...

ok now I understand

jayson

[allencr]

ok now I understand jayson

I only understand that the higher compression will require higher octane fuel, that it is no longer a non-interference engine but will need nothing else unless aftermarket cams are used and that the tensioner isn't useful unless modified for length or changed out for an earlier type.

[MisterJerk]

not only will you need to run 91 or 93 octane, timing will have to be retarded a few degrees from stock. I would recommend running a stage colder than stock plugs, NGK bcpr6es11 is what I run.
also, mine ran real rough at idle, so i disconnected the FPR vacuum line and plugged it. it will run full fuel pressure at idle.

what I need and should have got at the very beginning, Adjustable fuel pressure regulator and guage, and a wideband AF/R.

Does anyone know if you can use a wideband sensor with the stock ecu? which wire would i connect to the stock wiring, so i dont need multiple O2 sensors(ridiculous).

[yoshimitsuspeed]

not only will you need to run 91 or 93 octane, timing will have to be retarded a few degrees from stock. I would recommend running a stage colder than stock plugs, NGK bcpr6es11 is what I run.
also, mine ran real rough at idle, so i disconnected the FPR vacuum line and plugged it. it will run full fuel pressure at idle.

what I need and should have got at the very beginning, Adjustable fuel pressure regulator and guage, and a wideband AF/R.

Does anyone know if you can use a wideband sensor with the stock ecu? which wire would i connect to the stock wiring, so i dont need multiple O2 sensors(ridiculous).

You need a wideband with a narrowband output. The LC1 has two outputs and they are programmable so you can run one to the gauge and set the other one up to emulate a narrowband sensor and route it to your ECU or you can set it up as 0-5v and run it to aftermarket engine management or datalogger or whatever you want. A number of other widebands have similar features and some even more but I don't know much about them. I am running the LC1 emulating my NB on my car and it works pretty well. Sometimes it won't listen to the signal till I tap the gas once after startup. This causes a sweep that tells the ECU to listen to the signal. There are settings to adjust this in the LC1 so it may just be that I need to fiddle with it more but it's never been a problem for me. I just start it up, blip the throttle and it settles down to stoich right after that.
I can't see any reason why you would need to run more fuel pressure due to increased compression. I am running my 11:1 BT on my GZE ECU and it does just fine.

[krashdog]

not a "sunk in valve job", As Rogue pointed out the chamber wall where the ridge was... isn't by the bottom view. That ridge in the chamber wall gets very hot, and will cause ping/pre-ignition. minimize that sharp edge, and the chamber can withstand considerably more compression.

Ridge, or sharp edges I speak about...
[/quote]



ok now I understand

jayson[/quote]



so its like not having a 3 angle valve job its having a regular valve job with no sharp edges on the seat right?

and using higher octane gas for the lower compression makes sense...funny I just farted thinking about gas..lol

but also I would have to run a stand alone ecu for ?? higher combustion and for timing??

again thank you for everyone's input on this matter
jayson

[oldeskewltoy]

so its like not having a 3 angle valve job its having a regular valve job with no sharp edges on the seat right?

and using higher octane gas for the lower compression makes sense...funny I just farted thinking about gas..lol

but also I would have to run a stand alone ecu for ?? higher combustion and for timing??

again thank you for everyone's input on this matter
jayson

The sharp edges have nothing to do with the seats. The sharp edges in this chat are in the combustion chamber walls. They were put there when Toyota's machining equipment machined out the head originally.

The photo I used to try and explain WHAT those ridges were/are, has other work done to it... For purposes of this chat... all you are looking at are the area in the chamber itself. The valve seats also need work, both blending into the bowl walls, as well as a proper multi-angle valve job.

blending valve seats into port walls


NOTE the machining marks are in both photos: the 2 panel above, and the 3 angle below both show the original machining marks

multi-angle valve job

[MisterJerk]

I can't see any reason why you would need to run more fuel pressure due to increased compression. I am running my 11:1 BT on my GZE ECU and it does just fine.

I'm assuming you are using the gze 365cc injectors? or the BT 295cc(side feed, with ITBS)?

hmm..