high compression setup

[Classick Century Custom]

Impressive 12.1 compression is nice. I would like to ask how your acheiving this?... What is your motor setup internals and all.


With what I am doing I hope to gain 11 or perhaps as close to 12 as I can get, this is my setup that Ben recomended.

Head gasket set
head bolts
street/strip heads
street/strip manifold set
65mm TB w coolant bypass
forged 10.5:1 pistons with rings
strip camshaft
custom length pushrods

[geldartb]

Yeah, after getting all that trouble you had sorted out it would be a waste not to see how she does now. I didn't ever read what the issue was with the noise, what was it?

beats the hell out of me what the noise was. i took it all apart one last time and was ready to throw the stock cam back in but didnt feel like going through all the crap with pulling or dropping the engine down enough to get the cam out.

so i just re-timed the chain and gears and i think i torqued the cam gear to 106ft-lbs put it all back together started it up and it was uber quiet in that area.

you dont even know how happy i was when i started it up and it was quiet.

i tried an outing at the track but it seems my ICM was junk. it would cruise around town fine but when you nailed the gas it would just sputter like crazy. once i swapped that out it ran awesome. unfortunately i never made it back to the track and without a wideband it was probably a good thing.

right now im happy with the performance and i know with a good tune it will get better. but you know there is always that itch for more.

I can't recall if the dude with the 12.5:1 compression motor had posted the cam specs or not. Ben do you recall what they were? (the guy with 3400 with 3.4 pistons). For those of us with 3500 heads we can use the MLS to bring it to the same compression yet good quench so that seems like a great combo depending on how much cam we have to run...

id be interested in the specs of the cam he ran. if its something similar to mine that would be cool. to get the quench in the green using the CR calc the thickest off the shelf size MLS gasket thickness is .036 which would net the 12.54:1 CR

[pocket-rocket]

haha no its not a bad thing. this would require me getting a bigger cam probably. ill have to us Ben's service to see which would benefit more or which would would best. the cam i have now or a bigger one.

im not against either option. ill most likely go with it one way or another but not till next year, i want to see what the car as it sits now does.

Yeah, after getting all that trouble you had sorted out it would be a waste not to see how she does now. I didn't ever read what the issue was with the noise, what was it?

[IsaacHayes]

I can't recall if the dude with the 12.5:1 compression motor had posted the cam specs or not. Ben do you recall what they were? (the guy with 3400 with 3.4 pistons). For those of us with 3500 heads we can use the MLS to bring it to the same compression yet good quench so that seems like a great combo depending on how much cam we have to run...

[geldartb]

You say that like 12.5:1 would be a bad thing. I would love to have some way of a direct bolt in way to get 12.5:1 in my car without going custom, lol. I'm glad joelbob researched the whole thing with the N* pistons and stuff. I wouldn't mind following the same path to bump up my CR.

haha no its not a bad thing. this would require me getting a bigger cam probably. ill have to us Ben's service to see which would benefit more or which would would best. the cam i have now or a bigger one.

im not against either option. ill most likely go with it one way or another but not till next year, i want to see what the car as it sits now does.

[IsaacHayes]

try looking at a truck stop for a small ceramic heater that plugs into cig ltr plug. If you have an old enuf car that has cig ltr that is. they are small and sit on the dash to help keep your w/s defogged. trucks are not well designed most of the time. and they cant put glowing element stlye units inside the cabs. once u can see, just unplug and remove so it dont fly around during your heavy throttle romp to work.

You know me too well! LOL I actually have thought of getting one of those.



Joseph, my stock 3100 thermostat has a 2nd thing on the end which closes off a path in the LIM, which does what you described I believe. I tried a 180F stat once in summer, but those that fit that are not the stock 195F lack the extra piece on the end which seals up the other passage when it's closed........

http://contentinfo.autozone.com/znetcs/product-info/en/US/cst/7267-195/image/8/

But maybe it doesn't function that way... I'd have to think about it and it's late... LOL

[pocket-rocket]

another option was the .036 headgasket which would bring the quench down in the green and acceptable on the CR calc but would drive the CR up to something like 12.5.1

You say that like 12.5:1 would be a bad thing. I would love to have some way of a direct bolt in way to get 12.5:1 in my car without going custom, lol. I'm glad joelbob researched the whole thing with the N* pistons and stuff. I wouldn't mind following the same path to bump up my CR.

[geldartb]

Running those pistons with that gasket can be done but you will have to make valve relief cuts in the pistons which on assembly you can measure and then cut. You may loose a little bit of compression but it will add reliability to the engine build.

if the compression ratio is about the same as the pic i posted above then whatever i lose to making relief cuts in the pistons wont affect it much.

ill either do the piston flycuting like we talked about earlier in the thread or get some diamond pistons made with the reliefs already there.

another option was the .036 headgasket which would bring the quench down in the green and acceptable on the CR calc but would drive the CR up to something like 12.5.1

[john52216]

Running those pistons with that gasket can be done but you will have to make valve relief cuts in the pistons which on assembly you can measure and then cut. You may loose a little bit of compression but it will add reliability to the engine build.

[geldartb]

E10
Stoich - 14.1
PE A/F - 11.8

shit... That explains alot of my tuning lackingness.... I've been tuning to the quoted 12.5 or 12.8:1 YET I can ONLY get E10 in my area...

Well that's going to help some this summer when I start tuning again.

I guess that also explains why anything below 12.8 I could FEEL a power loss and was always confused on how the low end could be that close to where it should be "happy"

same here. once i get the wideband it will be good to do the tuning.

I swear I need to put cardboard over the radiator, that or when winter comes put in a thermostat higher than 195F... My co-works 4 runner will burn your face off in like 5 mins of starting the car... Mine you can sit and rev it for 10 mins and barely get luke warm. And it's not a clogged heater core or anything like that. The car just always runs cool no matter what.

That's a design flaw addressed in the 3900 and 3500 VVT motors. The thermostat appears to be dual stage. It has a block off for water inlet to the water pump and a smaller block off over a passage that allows recirculation of coolant through the engine connected to the heater hose so that coolant directed towards heating continues to circulate through the engine when the stat is mostly closed. That's what I devised from looking at the design when drilling a few by-pass holes into the thermostat base to allow a little bit cooler engine temp and reduce overheat risk in the event of a complete thermostat failure.

[robertisaar]

keep in mind, those PE numbers are calculated, it WILL vary depending on the motor. but it's a pretty good starting point.

[3400-95-Modified]

E10
Stoich - 14.1
PE A/F - 11.8

shit... That explains alot of my tuning lackingness.... I've been tuning to the quoted 12.5 or 12.8:1 YET I can ONLY get E10 in my area...

Well that's going to help some this summer when I start tuning again.

I guess that also explains why anything below 12.8 I could FEEL a power loss and was always confused on how the low end could be that close to where it should be "happy"

[robertisaar]

reminds me of the chart i made...

http://60degreev6.com/forum/attachment.php?attachmentid=2976&d=1256176289

[sprucegagt]

Since people are talking about E10 and high compression, I hope you all know that your cruise/idle AFRs should be 14.1:1, not 14.7:1.