my friend busted his timing belt, and bent some valves on piston #3. as i was replacing those bendt valves, i did not notice that the cams where in the down position(up was facing down) when i went to put the engine in time! as a result, i bent some valves on the # 3&4 cylinders. we went back and replaced those valves, but now we have no compression in either piston! i'm thinking that the valve guide might be bendt, or cracked! can anyone confirm that the problem lies on the valve stem seals, or chime in on what you think is wrong! TIA.

 

the valves that you did not replace are probably bent.....machine shop caught my bent valve i thought was straigh!

 

the funny thing, is that i did replace all 8 valves on cylinders# 3&4

 

i did take the head to a machine shop, and the guy found out that the valve's weren't seating right. so he cleaned up the valve seat, and the valve it self and tested them. they look good at the shop, but i got home there was no compression on the cylinders!

 

did you lap the valves in correctly? do a leak down to see if its the valves or something else leaking.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fulldragcrx &raquo;</TD></TR><TR><TD CLASS="quote">did you lap the valves in correctly? do a leak down to see if its the valves or something else leaking.</TD></TR></TABLE>


valve job was not done properly if you aren't getting compression!!!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fulldragcrx &raquo;</TD></TR><TR><TD CLASS="quote">did you lap the valves in correctly? do a leak down to see if its the valves or something else leaking.</TD></TR></TABLE>
how do i lap the valves? i don't have the leakdown tester! how would a leak down test show where the proble lies! thankx for the help!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by chad &raquo;</TD></TR><TR><TD CLASS="quote">
valve job was not done properly if you aren't getting compression!!!</TD></TR></TABLE>
the machine shop guy had this vacumm tester, he held it on each port. each port showed vacumm, except the exhaust ports on 3&4. he did something to the valve, and the valve seat and then those two port showed vacumm on the machine!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by chad &raquo;</TD></TR><TR><TD CLASS="quote">


valve job was not done properly if you aren't getting compression!!!</TD></TR></TABLE>
uh whoa there Mr. quick to answer guy. let me ask u if i take all the plugs out and crank my motor over will it have compression? Nope and my valves are fine. what i mean by all this is that the valves could very well be fine, odds are that they arent, but lets not jump to conclusions here.
A leak down tester can say alot. screw in a leak down tester and put the motor at TDC for #1. Pull your rad cap, if u see bubbles then you have a coolant sealing issue ( blown headgasket, cracked block or head) or crack open your TB and if you hear a loud hissing then the intake valves arent sealing and vice versa for the exahust ( listen to the tail pipe). Lapping in valves is a technique that uses valve lapping compound and a valve lap tool and is done by hand. the compound is gritty and it is put on the sealing surface of the valve and seat. the tool has a little suction cup on it and you stick the suction cup to the face of the valve with the valve in the head, work the tool and valve clock wise and counter clockwise, this creates a sanding effect that gives the valve a better seal. lastly did you do a valve adjustment???

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fulldragcrx &raquo;</TD></TR><TR><TD CLASS="quote">A leak down tester can say alot. screw in a leak down tester and put the motor at TDC for #1. Pull your rad cap, if u see bubbles then you have a coolant sealing issue ( blown headgasket, cracked block or head) or crack open your TB and if you hear a loud hissing then the intake valves arent sealing and vice versa for the exahust ( listen to the tail pipe). Lapping in valves is a technique that uses valve lapping compound and a valve lap tool and is done by hand. the compound is gritty and it is put on the sealing surface of the valve and seat. the tool has a little suction cup on it and you stick the suction cup to the face of the valve with the valve in the head, work the tool and valve clock wise and counter clockwise, this creates a sanding effect that gives the valve a better seal. lastly did you do a valve adjustment???</TD></TR></TABLE>
i did do a valve adjustment, before i bendt the valves! can i use a compressed air holding tank(the ones you can buy at pepboys), to check for the leaks you mentioned above? i have seen that valve lapping tool and the compund, at my local parts store! hey thankx for your help, i'm going to double check the valve adjustment!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fulldragcrx &raquo;</TD></TR><TR><TD CLASS="quote">
Lapping in valves is a technique that uses valve lapping compound and a valve lap tool and is done by hand. the compound is gritty and it is put on the sealing surface of the valve and seat. the tool has a little suction cup on it and you stick the suction cup to the face of the valve with the valve in the head, work the tool and valve clock wise and counter clockwise, this creates a sanding effect that gives the valve a better seal.</TD></TR></TABLE>



that's what i do to all the heads i rework. cheap yet if done correctly can make sure all the valve seats are sealing. though there may be another problem other than the valve seats. you'll have to look into some of the other things like fulldragcrx mentioned, like a leakdown test etc. valve adjustments are definantly a good idea as well, but you said you've already done that recently.

hope you figure out the problem soon!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fulldragcrx &raquo;</TD></TR><TR><TD CLASS="quote"> lastly did you do a valve adjustment???</TD></TR></TABLE>
i just finished doing a valve adjusment, and sure enough cylinders 3&4 where off by a mile! i got compression back on those two cylinders, let the engine idle for 20 minutes or so to check if everything is a ok! once i took the car on the road, it started to loose power! pushed it back to the house! i got compression, spark, and the correct timing, but the engine idles like is in three cylinders. if you hit the gas, it stalls out(like if the map sensor was bad)! i'm going to let it sit till tomorrow morning, and redo the valve adjustment! wish me luck

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by smokey2.0 &raquo;</TD></TR><TR><TD CLASS="quote">
i just finished doing a valve adjusment, and sure enough cylinders 3&4 where off by a mile! i got compression back on those two cylinders, let the engine idle for 20 minutes or so to check if everything is a ok! </TD></TR></TABLE>
see what i mean. I work on cars for a living, and i have seen people jump to conclusions and just start replaceing everything and now their car runs the same and they are out of money. its good that you listed this on HT and we able to get the car running. well i should say im glad you listend to me... but last thing, alot of people accidently reverse the connectors for the map and the tps. they have the same connectors. Make sure that you have the correct harness connector on the MAP and the correct one on the TPS. Not vice versa. good luck.

 

hey, thankx for your advice. actually, the map & the tps are in their right place. the car drove fine, but it lost power. right now it has compression in all four cylinders, the timing is correct, and there are no engine codes(i tried two ecus)! i'm just going to to one more valve adjustment, and check things over again!