Is this scenario even remotely possible?
Thread Starter
Launching!
Joined: Nov 2001
Posts: 229
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From: Cedar Hill, Tx
Is this scenario even remotely possible? I have Comp R lifters, ported heads milled .005, Isky double springs (the fat ones), and 7.400 PRs and a TR230 cam.
I wanted to try and run the car to let the Rs pump up so I could check the preload again and then buy some new PRs. I only tested one cylinder but it took two turns past 0 lash to get to 22lbs on the rocker bolt. I know, it's way too much for comp Rs.
Now my car cranks but will not start. I've checked all the things I should check (spark, fuel, grounds, fuses, sensors) all that stuff is good. The car backfires through the intake and blows the rubber hose off the manifold. I'm could almost bet my life that the timing is good because I was very **** about getting it right when I slid the cam in and bolted the sprockets on. (Unless there is a way to put the cam sprocket on backwards and there is a dot on both sides, the darn thing is dot to dot.) I've done it before and had no issues. ( I know how to install a cam)
Is it even REMOTELY possible that the preload is soooo tight that it would prevent the car from starting? Some valves are hanging open?
I'm gonna loosen the rockers a tad and try to start it. Just to see if it will fire off.
I wanted to try and run the car to let the Rs pump up so I could check the preload again and then buy some new PRs. I only tested one cylinder but it took two turns past 0 lash to get to 22lbs on the rocker bolt. I know, it's way too much for comp Rs.
Now my car cranks but will not start. I've checked all the things I should check (spark, fuel, grounds, fuses, sensors) all that stuff is good. The car backfires through the intake and blows the rubber hose off the manifold. I'm could almost bet my life that the timing is good because I was very **** about getting it right when I slid the cam in and bolted the sprockets on. (Unless there is a way to put the cam sprocket on backwards and there is a dot on both sides, the darn thing is dot to dot.) I've done it before and had no issues. ( I know how to install a cam)
Is it even REMOTELY possible that the preload is soooo tight that it would prevent the car from starting? Some valves are hanging open?
I'm gonna loosen the rockers a tad and try to start it. Just to see if it will fire off.
10 Second Club
Joined: Jun 2002
Posts: 1,884
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From: H-town
it is eather that your valves are still open due to PR beeing to long or the cam is a tooth off. both will cause backfire though intake. try loosing the rockers like you said and check it again.
Thread Starter
Launching!
Joined: Nov 2001
Posts: 229
Likes: 0
From: Cedar Hill, Tx
If #1 is at TDC then it's ready to start it's intake stroke, right? If so, then #8 should be half way up on it's compression stroke? If that is also true, then both valves should be closed, right?
My guess is that your valves are hanging open and your not building any compression. Try doing a compression check on one of the cylinders to verify. If that's the case, shim your rockers up or get some adjustable rockers.
Thread Starter
Launching!
Joined: Nov 2001
Posts: 229
Likes: 0
From: Cedar Hill, Tx
I bought the shortblock used. Is there any chance that the crank sprocket isn't lined up right? I was just chewing on all possible scenarios. Maybe they took off the crank sprocket and put it back on? Is the crank keyed so that the sprocket can only be put one in the right place?
I had pushrods that were too long and the car only ran on one side of the engine since the lifter preload differed about .010 from one side to the other.
I'd check both things as stated above.
I'd check both things as stated above.
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Thread Starter
Launching!
Joined: Nov 2001
Posts: 229
Likes: 0
From: Cedar Hill, Tx
Originally Posted by JC
If #1 is at TDC then it's ready to start it's intake stroke, right? If so, then #8 should be half way up on it's compression stroke? If that is also true, then both valves should be closed, right?
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You have way too much preload. Those only need 1/4-1/2 turn. You need 7.350 pushrods, and then you need to go through each rocker arm and shim them as necessary to get in this range. Too many don't spend the time to do this and it can really make a big difference in valve train noise with correct geometry.