mjr46

what year mustang are you working on?? are you chasing low compression probs, valvetrain noises or what was the original complaint with the idle?????? and what cam tfs stage 1????

nitrous_bob

i hate to ask a dumb question BUT.......

1) the motor was warmed up b4 the test right ?
2) did you dump a little oil ineach cylinderto see if the numbers picked up ?

94StinkinLincoln

what is your ring gap?

wolverine8490

Its a 91 mutang. Yeah well it did not start as chasing low compression. It started with a miss at idle and around 3000 rpm, and a bad stumble when holding the gas steady at about 10mph. The valvetrain noises started when I first adjusted the valves. It chattered really bad, which is why I turned the rockers 1 ful turn from zero lash. The cam I beleieve is the stage one. I bought the 350hp 370lb/trq kit.

1 - I did the test when it was cold as it is hard enough to get the plugs out cold without burning myself.
2 - I did not use any oil as it is a brand new build and I would hope to god the rings and seals are good.

I have no idea. I actually had the shop build the short block for piece of mind.

wolverine8490

I agree that the compression is very low. I do not have a pushrod measuring tool. I will pretty muchtry whatever you all think will fix the issue. I am hours away from selling/scraping this stupid *** thing. I have done everything by the instructions (which trick flows instructions suck btw) on this build and it has not gotton meanywhere. Pisses me off to spend 2500 bucks on a product that does not even work right. I bought the TFS kit cause it came with everything, I should have gone with AFR like I originally wanted to do and built my own kit.

Joel5.0

Don't worry about it, those are "growing pains" when you start getting involved with this stuff..... even if you would have had decided to go with AFR's, you need to do the valve train geometry/PR length setting exercise.... there's no way around it, that is, if you want to do it the right way.

Buy/borrow the adjustable PR's and make sure you check/set that geometry ....... is it really that important you ask?..... check this article .... not having it set correctly = you loose some of the cam induced lift..... a .510" lift could be .490" when set incorrectly.

mjr46

once your sure the valvetrain is set correctly like Joel5.0 says and you have no vaccum leaks then check your tune up parts like cap,rotor and wires....it doesn't matter if you say they are new...cause many times I've put new tune up parts on that right out of the box were crap.....2 years ago after a similar project of mine on my 66 I had a bad miss on my 66 build and Iwent bought a new cap...fixed it for 10 min and prob started again.....returned cap bought another and same result.......finally I said screw this cheap *** cap from napa's econoline and grabbed a used one that was still in fairly good shape with brass terminals instead of carbon ones and wham problem is gone...still got the used cap on to this date.......not saying that is your problem just an example double check all valvetrain set up and timing and work your way out from there

wolverine8490

Cool, thanks for the help. I ended up just sleeping on it so I did not break anything. A buddy of mine who has set valve trains is comming down today. He has a push rod measuring tool. I have rebuilt a couple engine before, but those engines always had torque specs for the rocker arms, so that made it easy.

As for the cheap parts, I am going to look into that as well. As I went cheap on the rotor button, cap, and wires. They are Autozone 1 years.

vtecwho

i hate to ask this but..... when the engine is warm what affect does that have on the engine. does it allow things to seal better and result is higher compression or is it the opposite???

wolverine8490

I was just reading about that, and they said normally that with the engine warm the rings expand, giving higher compression results.