need help with engine i built

jj7ski · Joined: 08 Jul 2009 Posts: 37

ok i just put together an engine to run in my spartan stock a few weeks ago. i bought a used stock 350. miles are unknown. i put a pretty big cam in it.its from speedway motors and specified its for modifieds. its a solid lifter cam. the specs are valve lift 534int and 522 exh. a working rpm range of 3500-7500. the part # is915-14101 if you want to look it up for more info. i have world products SR heads with 2.02 1.60 valves. dual coil valve springs with 1.52 comp cam roller tip rockers. have a holley dual plain contender intake and a holley 600 carb. running headers. i have an accel distributor with a supercoil, i removed the vacuum advance and put the weakest springs on for the mechanical advance curve. accel superstock wires and accel plugs. first of all the lower end is stock and since ive gotten it running its obviously pretty worn. i have blow by from the piston rings. i thought no big deal tho. i got it all timed up and sounded good with the open headers. i was excited to run it and see what it would do... well the damn thing has no bottom end power. as i pass 3000 rpm it gets a little better. after some tinkering i have a little more lower end power but not much. and not very good power thru the power band. i need help tuning this thing!!! if its possible that is .... and advise is much appreciated!! thanks josh

governor72 · Joined: 26 Jul 2006 Posts: 213 Location: Charlotte

Did you put the new cam and lifters in? If yes did you use any type of breakin oil or additive, plus what oil did you use if not breakin oil? Did you let it set and idle when you first started it?

Can I assume you know the correct way to lash the valves?

The first thing I would do now is ck the compression, once you have that data post it here.

Gov

jj7ski · Joined: 08 Jul 2009 Posts: 37

yes i installed the cam and lifters.i used valvoline maxlife oil. but i used lucas assembly lube on the cam and all the lifters. i used almost the whole thing of lube. this is the first engine ive installed a cam in. i dont know how to adjust or check valve lash. but when i adjusted the valves, i adjusted each valve one at a time. i adjusted them to the point where there was very little movement to the rockers with my fingers. i must have turned the engine by hand 200 times haha! i know it wasnt ideal but based on my knowledge thats how i did it. i dont have a compression tester but last night i was double checking the timing so i was finding tdc and removed #1 spark plug and plugged the hole with my thumb. when doing so i was waiting to feel the compression to push my thumb out. well that never happend. i have very little to no compression. ive heard it should be nearly impossible to keep the hole plugged when doing this. well that wasnt the case. so the bottom end is junk. so i think i have to wait until next season while i have this block machined and rebuilt or look for a new block. thanks for your interest in helping. i hope to see the track soon.

flying14 · Joined: 29 Aug 2009 Posts: 113

that may not totally be the case, if a valve is hanging open then you won't feel any compression because the air will just escape. i would find someone who can help you lash the valves first before i consider the bottom end junk. Also ditch the max life oil, instead get VR1 and run in it, probably 20w-50 or 50W. but first things first i would definately have someone lash the valves if you don't know how, or look up the procedure off the internet and try it yourself again, the cam should have a valve lash spec that you need to set it at.

jj7ski · Joined: 08 Jul 2009 Posts: 37

well the valves and springs are all brand new. could that still be a possibility?

MaddMike · Joined: 12 May 2008 Posts: 64

the engine will never run right if you don't lash the valves properly...and aside from that, it could result in a catastrophic failure.

If you are just setting them with a perceptible amount of play...then likely you are setting them way tighter than they should be which is making your cam way bigger than it actually is...which will kill bottom end.

Also..if that is the case, you may have an amount of valve overlap that is preventing it from building any compression while cranking.

And lastly- As the Governor was getting to...break-in procedure is critical on flat-tappet camshafts. You may have damaged the camshaft... When you re-check the valves and lash them properly, make a note of any that were looser than the others.... If that one gets loose again quicker than the others, there's a problem.

Where are you located? Someone might volunteer to help.

Mike

jj7ski · Joined: 08 Jul 2009 Posts: 37

well it wouldnt run very well at the begining so i wasnt able to let it just sit and idle. hell it barely runs by itself below 1500 rpms. im definitely getting some feeler guages and resetting the valves. i hope i didnt ruin the cam. i live on the south side of lansing. near the corner of washington and northrup. someone volunteering to help would be great!

jj7ski · Joined: 08 Jul 2009 Posts: 37

also i need a set of 3/8 poly locks. i bought a set of 7/16 not knowing they were the wrong size. if anyone has some i would like to trade

MaddMike · Joined: 12 May 2008 Posts: 64

Well the fact that it wouldn't idle is a good thing. NEw cam breakin requires a lot of varying RPMS to splash oil on the cam, and idling is bad.

On the poly locks- Does your budget allow you to upgrade to 7/16 studs and rocker arms? This would be a worthwhile investment.

Mike

jj7ski · Joined: 08 Jul 2009 Posts: 37

No the budget is pretty tight. It would be much more comfortable to only have to buy the poly locks. Especially when I already bought them just the wrong size. If I could I'd like to trade them but if not then ill keep them for the off season. I just hope I didn't ruin the cam in the process. Well I will be readjusting the valves this weekend. I'm going to be at the track either next friday oer the one after.