Some of you may have seen this drama unfold on my build thread
http://www.motownmuscle.com/forums/showthread.php?166854-78-caballero/page7
I have a 4-bolt 350 with 30 over pistons and I suspect may have been decked while they were at it (didnt think to measure it when it was appart)
The car was running and driving when I pulled the engine.
I didnt trust the last owner and the engine looked like doo-doo so the scope of work was basically just gasket replacement, check torques, clean and re-paint. I didnt even bother taking any of the caps off as the engine ran great with no noise, so I backed all the main and rod cap bolts back by a quarter turn and re-torqued them.
The only issue I found on the engine was some one left a manual transmission pilot bushing in the end of the crank shaft and the torque converter wasnt able to sit properly bending the flex plate a bit.
I put every thing back together, cleaned and painted all happy, put it back in the car and it wouldnt crank over with the plugs in it, plugs removed it would turn over.
1) I suspected electrical issues so I eventually got a set of jumper cables attached them to my running daily driver, attached the positive to the cylinoid lug, and the negitive directly to the starter casing.... No improvement
2) I suspected the starter mesh wasnt right so I shimmed it, less noise... No improvement
3) I suspected the starter went bad (as the cylinoid terminals felt loose) so I swapped it for a new duralast cheap and chearfull stock starter... No improvement
I pulled engine popped it up on an engine stand (with flex plate and starter still attached), put a torque wrench on the under drive pully and with plugs out it required 45ft lbs to turn it over.
4) I rolled the engine over, removed the oil pan, pulled the oil pump off, checked that all the caps were on correctly, loosened up every main and rod cap; turned engine over using the torque wrench and still got 45ft lbs.
5) I rolled the engine over again removed harmonic ballancer, distributer and pushrods (to rule out vavle interfearences); again with spark plugs removed it took a little less than 45 ft lbs to turn it over but nothing too significant
6) Conserned the flex plate being bent created inconsistant mesh with starter I replaced the flex plate, shimmed starter, tightened rockers back down (on compression stroke tighetned the rockers down till I no longer felt a clicking when pulling pushrod up and down, then an additional 1/4 turn) pulled timing cover off and re-set timing marks streight up (last owner had it retarted by a tooth) and re installed plugs... No improvement
It dosent feel like a mechanical stop. When turning it over by hand when one of the pistons comes up on compression it gets tight (as you would expect) but you dont feel a positive lock or click just an increase in resistance. When the engine stops if you sit for a few seconds and bump the starter again it will make it past that compression stroke and stop on the next.
7) Pulled all the plugs again and got a pressure gauge on one of the cylinders. Engine turned over 4-5 times then stopped again after the pressure reached a max of 170ish psi.
I have avoided it to this point but im affraid I have no choice but to pull the heads again. The only possibilitys in my mind at this point are there being alot of crap still in the cylinders from when I was cleaning the deck (I tried my best to keep this down to a minimum but you never know), If the engine was decked and I put standard thickness gaskets on it perhaps the compression is too high, or I am totally miss reading the feel and the valves are actually hitting the pistons (unlikely as it was still acting that way with the valve train loose).
Any ideas on what may be the cause of this? any thing I should look for when I take the heads off?
My game plan is to pull the heads, pull the pistons, clean the bores, inspect the caps and bearings, re-assemble with assembily lube, check piston to deck clearence, check valve to piston clearence with stock gaskets..
If all that looks good Im going to get the plastigauge stuff and check bearing tollerence (very unlikely as it wasnt an issue before)
http://www.motownmuscle.com/forums/showthread.php?166854-78-caballero/page7
I have a 4-bolt 350 with 30 over pistons and I suspect may have been decked while they were at it (didnt think to measure it when it was appart)
The car was running and driving when I pulled the engine.
I didnt trust the last owner and the engine looked like doo-doo so the scope of work was basically just gasket replacement, check torques, clean and re-paint. I didnt even bother taking any of the caps off as the engine ran great with no noise, so I backed all the main and rod cap bolts back by a quarter turn and re-torqued them.
The only issue I found on the engine was some one left a manual transmission pilot bushing in the end of the crank shaft and the torque converter wasnt able to sit properly bending the flex plate a bit.
I put every thing back together, cleaned and painted all happy, put it back in the car and it wouldnt crank over with the plugs in it, plugs removed it would turn over.
1) I suspected electrical issues so I eventually got a set of jumper cables attached them to my running daily driver, attached the positive to the cylinoid lug, and the negitive directly to the starter casing.... No improvement
2) I suspected the starter mesh wasnt right so I shimmed it, less noise... No improvement
3) I suspected the starter went bad (as the cylinoid terminals felt loose) so I swapped it for a new duralast cheap and chearfull stock starter... No improvement
I pulled engine popped it up on an engine stand (with flex plate and starter still attached), put a torque wrench on the under drive pully and with plugs out it required 45ft lbs to turn it over.
4) I rolled the engine over, removed the oil pan, pulled the oil pump off, checked that all the caps were on correctly, loosened up every main and rod cap; turned engine over using the torque wrench and still got 45ft lbs.
5) I rolled the engine over again removed harmonic ballancer, distributer and pushrods (to rule out vavle interfearences); again with spark plugs removed it took a little less than 45 ft lbs to turn it over but nothing too significant
6) Conserned the flex plate being bent created inconsistant mesh with starter I replaced the flex plate, shimmed starter, tightened rockers back down (on compression stroke tighetned the rockers down till I no longer felt a clicking when pulling pushrod up and down, then an additional 1/4 turn) pulled timing cover off and re-set timing marks streight up (last owner had it retarted by a tooth) and re installed plugs... No improvement
It dosent feel like a mechanical stop. When turning it over by hand when one of the pistons comes up on compression it gets tight (as you would expect) but you dont feel a positive lock or click just an increase in resistance. When the engine stops if you sit for a few seconds and bump the starter again it will make it past that compression stroke and stop on the next.
7) Pulled all the plugs again and got a pressure gauge on one of the cylinders. Engine turned over 4-5 times then stopped again after the pressure reached a max of 170ish psi.
I have avoided it to this point but im affraid I have no choice but to pull the heads again. The only possibilitys in my mind at this point are there being alot of crap still in the cylinders from when I was cleaning the deck (I tried my best to keep this down to a minimum but you never know), If the engine was decked and I put standard thickness gaskets on it perhaps the compression is too high, or I am totally miss reading the feel and the valves are actually hitting the pistons (unlikely as it was still acting that way with the valve train loose).
Any ideas on what may be the cause of this? any thing I should look for when I take the heads off?
My game plan is to pull the heads, pull the pistons, clean the bores, inspect the caps and bearings, re-assemble with assembily lube, check piston to deck clearence, check valve to piston clearence with stock gaskets..
If all that looks good Im going to get the plastigauge stuff and check bearing tollerence (very unlikely as it wasnt an issue before)
