Ls1 PR Length - don't be a JEFF
 

PSA - My name is Jeff.... I built my 1st LS1 for my project car... i have experience with roller sm block fords.... so no need for the Ls1 engine manual? right?
Fast-forward 3 yrs later.... my LS1 H/C/I build just never ran right.... poor idle which was variable.... sometimes hanging high.. sometimes stalling...... terrible throttle response..... weak mid range.... all top end..... terrible valve train noise...... 3 tuners could not manage to figure it out..... it ran OK..... but I was never happy with it......

I was about to pull the LS1 in favor of a bigger ci mill...... or add a bigger cam...... or diff h/c/i setup.

Then one day (last week) I saw a thread about measuring PR length..... so I pulled the rr's.... and measured and they were too short.
In JEFF's defense the TFS genx kit came with everything necessay (incl pr's)...... but I recall using different head gaskets which were probably thicker......

All above drivability issues resolved..... and holy cow the mid and top end are back!

So don't be a JEFF....... read your Ls1 engine builders specs... follow instructions...... and make some power.

PSA Over.

Wow that's awesome, two guys in one week checking PR length and getting everything figured out. Nice work glad to hear its running so much better.

I wonder how many people blamed the tuners..........

My guess is probably 98-99% of them.

I think the problem we run into IMO is not all tuners are mechanics, and we are hoping the tuner can resolve all the cars issues with a laptop.

Running the lifters closer to a solid makes makes more power but it is harder on the lifters. It's finding the sweet spot that a particular lifter likes to operate. To little and it will tick indicating poor oil lubrication, power loss and a short lifter life while too much causes more stress to the hydraulic lifter. One good reason why adjustable rocker arms are a plus to a valvetrain setup.

Jeff would have been OK if he had stayed "within the lines", BUT he then said he used thicker HG's! Threw everything off.....
Just change ONE THING, and you need to measure. He should have anyway just to be sure, but stray from the proven assures it.

Completely agree with this.

Engine
 

I always knew something was not quite right.

you guys know the sound a healthy engine makes at idle and part and wot… the cam and exhaust sing.

w the wrong pr this thing was anemic and lazy… idle was weird… no distinct rumble…

I bet the tuners were scratching their heads on this car

ill bring this in to check the tune very soon


its a totally different car now… I was actually thinking of punting and selling this and getting a c.5 z06


dont be a JEFF :)

Excited to see where the car is at now! Keep us posted, glad you got it figured out!

I'm always impressed with anyone who posts up about a problem like this that they fixed...especially with a list of symptoms. It sucks you had to live with it for three years. I'm glad you got it figured out. I agree with LilJayV10, tons of tuners get thrown under the bus over stuff like this...

Tune
 

If I had a tuning business I would ask customers about this very thing

one did in a round about way-/. Who build this engine? I said me. They said sign this paper saying we are not resp if it fails.

Y’all should make this a sticky, so many mess up on the pushrods. Glad you figured out your issue Jeff.

Poster child
 

Agreed on making Jeff the poster child.. and a sticky.

this simple step cost me years of troubleshooting retunes and self doubt.

don’t be a jEFF!

Not to highjack your thread, but on my 1st engine build (chevy 350):
-broke in solid lifter cam with the regular valve springs
-broke off a rocker arm stud everyday until I upgraded to better ones
-sprung an oil leak from the balancer seal because I reused the old balancer and didnt clean it up at all

I ended up selling the car (1969 camaro) for 7k, new owner told me I had wiped off two lobes on the rear of the cam
He had a new engine put in the car then wrecked it a month later

Major credit to the OP for sharing all the details of the issue and solution. Excellent candidate for a sticky IMHO.

A++