Ct-525

**poppy** · 07-10-2011, 01:57 PM

I need help! I have a CT-525 with about 1 season on it. Never ran over 7500 RPM, never been hot and always had good oil preasure. My problem started when I blew a motor last week, took the bottom end out. Number four pistion was completely gone. And I think that is what started it all. I put a new CT-525 in and 15 laps later number 4 pistion is gone and not much left of the bottom end. Was turning about 7300 RPM and no warning signs, did not start to knock or miss just Kaboom. Anyone have any ideas on what could cause this? MSD box? Need help.

**poppy** · 07-10-2011, 05:23 PM

No Ideas? Need help.

**MasterSbilt_Racer** · 07-10-2011, 05:51 PM

I guess I would look at ignition problem first. Could be fuel delivery if that is the first cylinder to lean out on those engines? I have no idea about that.

**wishiwasfast** · 07-11-2011, 07:17 PM

I would lean more towards valve float, causing a valve to hit and fracture then shatter the piston. I'm pretty sure those engines redline at about 6800. I think its just coincedence it was the same piston in both engines. If you're allowed to change valve springs the Comp #918 spring would be a good replacement, the PAC racing equivalent spring even better.

**poppy** · 07-11-2011, 07:45 PM

where do you get those springs?

**wishiwasfast** · 07-11-2011, 11:32 PM

Any local parts house or your local machine shop should be able to get them, or you could get them directly from the manufacturer. Comps full p/n is #26918, the number for the PAC spring is PAC-1218. The Comps run about $180, the PACs about $210 for a full set. Both are a direct replacement for the stock spring.

If you decide to buy springs, please support your local machine shop or private-owned parts house and not go the big-box store route.

**Egoracing** · 07-12-2011, 07:17 AM

I did not think you were legel if you changed out the springs.

**poppy** · 07-12-2011, 09:52 AM

Ego I think you are right. Also I am being told that if you run a MAP sensor with a timing chip suppled by GM that if the MAP sensor goes bad it can throw the timing all over the place. Anybody have any experience with this?

**wishiwasfast** · 07-12-2011, 12:51 PM

Isn't it OK to change out the springs on the 602 & 604 crate motors? I've never messed with the crates so I'm just asking........

**poppy** · 07-12-2011, 01:20 PM

Not at our tracks. I know guys were doing it with look a like springs. the 604/602 the springs were the weak link in those motors, I mean weak.

**sj valley dave** · 07-12-2011, 03:29 PM

If you can change out springs, it would be the GM part only...No aftermarket stuff...

**sj valley dave** · 07-12-2011, 03:38 PM

If you can change out springs, it would be the GM part only...No aftermarket stuff...

**dynoman14** · 05-03-2012, 02:07 AM

Are you running fuel injection or Carbureted?
Have you had you CPU's Fuel map checked if injected?

Just a guess but since you killed 2 engines in the same car I am guessing it was fuel related, like burning a piston and then dropping a valve and then kicking rods out the side. Pretty common with Ill tuned CT525's.

I spent about 4 weeks getting 2 dirt cars sorted out over the winter. Customer went from 604's to CT525's, new from the engine builder and tuner these engines would have have blown up their first race. The fuel curve was totally off, ignition curve was fully advance at 1500rpms @ 40*, many of the help provisions for extra fuel when over heating and lean knock conditions were bypassed. The person who set them up on the engine dyno must have been an Import Car tuner and bozo at best.

It took about a week just to get the CPU to run right with the engine and then another week to even get close to 525HP. Week 3 and 4 were spent testing headers, fuel, different fuel maps and changing ignition systems and coil paks around. Injectors sucked so I had to go thru them and make then decent. After that it was good news, one car had 576RWHP and the other one had 582RWHP. Still not as much as my 621RWHP out of my Katech ASA LS-1 but it was a good start.

Anyone want to buy a killer LS-1 with dyno time only???

**dynoman14** · 05-05-2012, 07:30 PM

Livin truth,

Wow, such a nice comment from such a knowledgeable person. I guess if you weren't such a know it all you might have caught wind of this project.

I never said what the plans were for the project now did I???

If you were halfway intelligent like a couple other folks on here you could have e-mailed me to find out why was it that I had 2 CT-525's with FI in the first place???

Could it be because I tested the original LS-1's with Gary St.Amant when they first came out in ASA thru GM, Katech and Lingenfelter; when my shop was 5 miles from Lanier and I was working there and we practiced there about 3 days a week during the winter.

Or maybe it is because I am the only guy in the country that knows those systems like the back of my hand because I purchased about 25 of those engines from GM when they $hitcanned the program. I guess they knew where to come looking when they wanted to do some testing for the future.

Whatever it is I know the check cashed for $26,000 for 2 weeks of testing plus parts.

I am pretty sure the cars will be running as flat side pavement late models this year for test purposes as they were nice and clean and had pavement Hoosiers on them. In Michigan and WI, they have classes that allow dirt cars on pavement, and when I was at Lanier they were going to do the same thing but never had a great turn-out. I think they ran 3-4 times and only 4-5 cars showed up.

Also your information is way off on hydraulic lifters but what else could I expect, to know this you would have to be able to read the GM Performance Parts Bulletins listing lifters for racing Corvettes, Camaros and Cadillacs. How do those guys turn 8500??? Or am I lying about that too???

Oh wait, I bet you are not on the list to get those GM Bulletins. Oops.

Anyway, if things go well you might see some injected LS-1's in Super Racing next year...

http://www.gmperformanceparts.com/Ra...ll_martens.jsp

**Egoracing** · 05-05-2012, 08:24 PM

Dunk, why would you ask a question then argue about how much you know when there is not 1 FI 525 crate engine in existance? Quit trying to impress people whit what you think you know and then talking in circles when they find all the flaws in your stories. Same old dyno, I had my parts on the top 3 cars a that race when in reality there were none then you tried to say you were talking about a totally different race.