I pulled this engine apart last month and had 3 piston skirts broken off and laying the oil pan. I gave the 2.4 block to my friend and he is doing a higher effort 2.4 build with forged pistons and crank, girdle, 2150cc injectors, sheet metal intake, etc, etc. He is hoping to make 500whp, we...

Right. 4G63 head on 8valve engine. The pistons are clearance for sohc head. The valves don't have much clearance because the valve reliefs are not in the correct position with the 4G63 head.

The only pistons that will give this high of compression are the SOHC pistons from the G4CS. I think we talked over earlier (I did not look back in the thread) that the 4G64 pistons do not have the same dome to them.I can't remember now what the clearance was, but one tooth off on cam...

That's it. Still running the same boost and performance. I went to farrier school and have been working with horses a lot this last year so it has never made it to a dyno yet. I will have to dyno my rx7 so maybe when I get to that I will also be able to dyno this car. I know jacks...

I am still driving it, but only about once a week. It is still the same configuration. In the meantime we installed MS2 on my friends talon. Right now I am working on my V8 rx7. I have an MS3 to put on it so I am playing with that. My Talon needs a paint job really bad, otherwise I just...

Same for me, I swapped everything from my 4g63 so the oil gauge is in the same place it was on the 4g63.

http://www.dsmtuners.com/forums/newbie-forum/196177-timing-belt-accessories.html

Most of this has been hashed over earlier in the thread, but 4g63 pistons do not yield nearly the compression because of their dish. You can look back through the different pictures in this thread to see what I mean. I would love to have high compression wiseco or magnus pistons, but I'm a...

I am noticing that the rear has a lot of slack in it these days. I use to have a four bolt rear waiting to swap in, but I sold it. Hope this one holds on for a while. Automatic would be really fun in this car, maybe I will look that direction. I hadn't really been thinking about it but you...

I have not installed my 272 cams yet. I am liking the low end grunt with the stock cams and high compression so much that I am afraid to change cams. This car gets off the line so quick and in the boost so early that it is tons of fun on the street. I am just enjoying driving it for now, I am...

Same exact symptons on my friends car last year. Ran good, pulled hard, but idle would surge. Checked compression and had 3 good cylinders and one at 60psi. Pulled the head and found that a valve seat was burned/no longer sealing and causing the low compression. Had valve job done and put it...

My friend is building a new engine right now and I am helping him. After that I should get time to rebuild mine with the new pistons and cams. I need to order pistons and injectors.

I think the manual says to wire the coil power to come on with the fuel pump. Otherwise if the coils have power with key on, the megasquirt is just getting powered on and the coil trigger wires are unknown for the 1st split second which causes backfires. I had the backfire problem with another...

You can verify that Megasquirt is getting a signal from the CAS by opening Megatune and looking at the RPM gauge while cranking over the engine.

It wouldn't bother me to run on cast pistons, I am doing it at low boost 14psi on 12:1 compression. I would be careful with tuning and take it slow on timing and boost. Otherwise it isn't hard to change pistons when they crack up so I would go for it. I bet it will last longer than you think...

Yeah, I talked to Jack about that build before I started this one, that is what I was mentioning in the first thread that the local guy had already built this combo and claimed like 11:1 compression(it is actually closer to 12:1 with a single head gasket). BTW, I got my HKS 272 cams.

No, I never did. I'll try to keep my promise and dyno before I make any more changes.

Thought I would throw another update. Car is still running good, I'm starting to get bored with the ~300hp level. I think I want to get some lower compression forged pistons in the engine now and a new turbo with a high pressure ration so I can get up in the 30psi area at my altitude of 6000+...

I just used a felpro gasket for the turbo 4g63 and the bores were already oversized enough to fit the 2.4 block, but most people don't want to use a felpro.

Thanks for updating. I only ended up with the higher compression by using the 2.4 SOHC pistons. BTW, my engine is still running good at 14psi boost. I still love the way it drives and the off idle response it has.

I also run the v2.2 board. Use the instructions at diyautotune like mentioned to mod the board.

I replace mine every 40K. My last idler bearing was toast at 40k when I changed everything. But I use ITM components so maybe 60K is comfortable on OEM components.

Yeah, I hear ya. I haven't had a knock sensor to tune with for the last couple years.

I wish MS1 hires was that good, buts its 33so 100,33,1 for the three. I wondered because I went from MS1 to MS1 hires and still didn't control the 150pund injectors on my LS1 very well. I think MSII would do the trick though.

I think something may be wrong in the statements about injector resolution in hires vs MSII. The Hires code says in the readme it provides about 2.5 times the resolution from MSI for injector control. The MSII upgrade page says it provide 100 times the resolution from MS1. Just a minor...

The car is still running good. Still waiting on my friend to get his car back from paint. I've put around 3k miles on it now and I love the low end performance for daily driving.

I had to remove my clutch assembly twice because I welded it the first time, the second time I just put all new parts in.

Yes!

Yeah, its amazing in this day and age to think back then that kind of public killing of animals was happening. I would say this guy is a good example of why a 48volt car system would be safer, or disconnecting the battery before working on it ROFL Sorry, but we do like to laugh at other...

I think you got that backwards, but it doesn't really matter. I thought Edison used AC currect to fry animals to show how unsafe Tesla's AC power was. DC, he thought, was nice and safe for everyday use. I have been shocked by a DC welder, its possible. I agree with the other guy that the...

I did use the standard felpro gasket, it has the larger bore diameter. It is not really a question of how far the valves travel, it really depends on the cams duration and ramps. When the cam starts to open the intake valve and how fast it opens, that is the critical spot that you will hit the...

Theoretically the high end is 13:1, but I think i am seeing more like 12-12.5:1. It starts to depend on a lot of factors like HG thickness, piston to deck clearance, milling, etc. I am not hitting the piston with the valve even though the reliefs are not there, but it is running close.

Yeah, but the pistons are determined by the head. They don't put 2 valve relief pistons with a 4 valve head and you want the 2 relief pistons for the high compression.This is the piston you want for this higher compression, notice its for an 8 valve engine and basically a flat top:

I just went up to the search and entered "8 valve 4g64", looks like they came in trucks and vans, probably other stuff as well.

From the thread in the newbie area it came to my attention to point out that you need an 8 valve 2.4 block with the 4g63 head to arrive at this compression. The G4CS I used was 8 valve. If you use a 4G64 then it needs to be 8 valve, so truck, van , etc.That will give you this piston which...

I don't know what you have then. good luckEDIT It just occurred to me, you need pistons from a 8v SOHC. So an 8 valve 4G64 would work if there was such a thing.

You have BC 280 cams according to your profile, that will make a difference on cranking PSI compression measurements. You also list wiseco pistons, what CR are they?

If they made a 4G64 that was 8 valve SOHC it would yield the same results.

Unless there are other engine blocks stamped with G4CS and my 1990 Talon TSI came with a different head than a 4G63, I am positive that is what I have, but anyone is welcome to visually inspect and verify. I don't have a problem with that. The pistons are the G4CS SOHC types. The compression...

I had to shim the pivot ball and replace the clutch pedal/bushings to get my clutch to work properly.

I set my dual boost switch for 14psi last night and tried it out. 14 pounds feels really good, pulls better than 18psi did with the old 2.0. That gives me 9psi on the low setting for typical driving and 14psi when the need arises.

Anyone thinking about running this same combo should read the following link and remember that I am running dedicated E85 at high altitude.KB Performance Pistons-Bench Racing

I talked to my friend about getting both cars on the dyno after his paint job, he also wants to do this. Hopefully in a month we will have results. I checked compression again at his house his and it showed 220psi on all four with his gauge at 6000 feet. Did not get any video, sorry, but I...

This is a megasquirt car so no airflow numbers I'm afraid. I had no plan to take it to the track since overall it is a slow daily driver, but I would like to get it on the local dyno and compare to my friends talon who has the indentical setup to my old 2.0 setup. We should be able to compare...

I am at 500 miles on the setup now. The new CFDF clutch should be broken in well. When the car ran on pump gas with 2.0 I would get 27mpg. When I switched the 2.0 to e85 I had to increase fuel by 34% which put my mileage at 18mpg. With the 2.4 engine now I am getting 22mpg. I am only down...

I'll try to shoot some video this weekend, just need a second person to get some good driving footage.

I drive it 60 miles a day to work. So far so good. I can get going from a dead stop so much quicker now without having to rev the engine. Just take off like a typical non turbo car and then boost hits quickly as well. As this point I am a little worried about how long it will last, but I am...

I have that knock sensor for my megasquirt rx7, but I read a few threads that it did not work well for people.

Did you order the parts from futurelec like their site recommends? I ordered some parts from there and it wasn't very long before my credit card started get fraudulent charges from the same area. Had to cancel it and swore off ordering directly from asia anymore.

Megasquirt, so no knock sensor. Supposedly you can use a knock sensor with it but I never heard of anyone having success with that. Scary huh? It is almost unheard of for people with DSMs to not use a knock sensor to tune with, but it is what it is.