Over reving: valve train damage?

[HondaBoy]

ok, well as my car doesnt have a rev limiter i have accidentally over revved the engine and it started acting up as it did before when it was revved too high. what it did was dump fuel from the carb's primary venturi and wouldnt idle for shit due to this. tried adjusting it, didnt help at all. drove it on the freeway doing about 80-90 mph on a streatch, drove it sort of hard, and that freed up the problem. any of y'all that know valve trains, maybe the valve spring lifed and settled abnormally? i'm going to have to check the clearance of the valves when the engine has sat over night i guess, but i was thinking the spring because it cleared up after what i like to call and "italian tune up". doesnt seem to have low compression, but i havent had a chance or the tool to check that either. any ideas will be of some help.

[AccordEpicenter]

I got an idea: Dont overrev your motor

[HondaBoy]

problem is i already did, a few times, not on purpose but because the tranny didnt shift when it was supposed to. but yeah, 8 grand sounds wicked. 1st gear to 60. not good, but an experience. probably shouldnt do that until i get stiffer springs and new parts.

[ghettogeddy]

I got an idea: Dont overrev your motor
:Owned:

[AccordEpicenter]

keep doing that and youll either lose a rod or rod bearing or start smashing valves. I dont even go that high on a BUILT bottom end and BUILT head

[AccordB20A]

mine kinda cant go that high cause of revlimiter but i know what its like when ur auto box doesnt shift my other accord did it till it got the revlimiter and i was like ayeeeeeee. sounds like u have a carb vehicle. i know one thing about accord carbs ..they allways fuck out. maybe at that rpm an intake valve wasnt fully shut when it was sposed to be and it backfired out the carby and fucked sumthing in the carb i dunno.. my 2 cents

[HondaBoy]

well the carb is in fine condition, i just rebuilt it and thats not really the problem. i've ruled that out because i thought that was the problem last time and rebuilt another carb and installed it. as far as the vacuum its pulling, 21 inches. again, i think its something in the valve train. wheather it be a burnt valve, stuck valve, worn rocker or f'ed up spring. well i guess until i do a compression test and check valve clearnaces, i really wont know. but keep the ideas comming so i can check other things. and really, i didnt want to over rev it. it just kind of happened.

[MessyHonda]

i got an idea.......get a 5 speed.....then you dont have to worry about your tranny shifting under load.

[88Accord-DX]

Compression test are good. If you have an air compressor & leak down gauge, that'll tell you if your valve is (burned, spring broken, etc.) Just make sure the cylinder your testing is on TDC.

[ChaseR]

I go to 8grand everyday in My motor...

[A18A]

^cool avatar

[MessyHonda]

I go to 8grand everyday in My motor...



your car was made for that kind of abuse. :bandance:

[diegoaccord]

I go to 8grand everyday in My motor...

Ive gone to 10K a few times. :Owned:

[ChaseR]

Ive gone to 10K a few times. :Owned:

When I Skunk2 my Head, I should be good for 10k!

[2oodoor]

I go to 8grand everyday in My motor...
FYI everybody , this is not an A20

If you had valve springs popping out of thier perch you have big problems!!!lmao

It comes a time when you start to notice the speedometer is not moving as far over as the tachometer like it was before 5K rpm, it might be a good idea to shift if you want to go faster.

My guess for the rough running problem is the secondary throttle shaft got stuck a little and was open some at idle.

[MessyHonda]

It comes a time when you start to notice the speedometer is not moving as far over as the tachometer like it was before 5K rpm, it might be a good idea to shift if you want to go faster.



he has an auto :violin:

[HondaBoy]

hey, so my motor doesnt stop pulling at 5000 rpm or at the red line. either way, i wasnt trying to get it up that high. like i said, it happened without me really thinking about it as the tranny usually shifts by itself and i was looking in my rear view mirror. ok so besides that, could that much venturi vacuum from such a high rpm pop or dislodge an O ring? its started to clear up quite a bit and isnt dumping fuel. when i had replaced the O ring on the primary venturi, it quit doing it this crap last time. also, i was wondering if added ethanol would deteriorate my carb's O ring quickly? just a though, but i dunno if the fuel i use is made with more than before the staitions switched to the new brand of gasoline.

[AccordEpicenter]

dunno but you need a rev limiter before you blow it, set it at 7200rpm max

[HondaBoy]

yeah, that'd probably be good. with my header and exhaust it has been able to keep power much past the red line. i was going to buy an MSD ignition box someone was trying to sell me but i'd rather buy one new. they arent that expensive but right now i dont have the money to blow on that kind of part. and i'm wanting to install a performance cam and do some head work. so yeah, would be a great idea to get a box with a rev limiter.

[russiankid]

Can't you just watch the rpms and before 7000 just let off the gas a bit and it will shift?

[HondaBoy]

yeah that usually works, but i was looking at a car in my rear view and lost track of what the motor was doing. not trying to burn up my engine, so i wont be doing that again.

[AccordEpicenter]

i believe you can get just the msd rev limiter itself instead of the whole box... but i could be wrong

[russiankid]

yeah that usually works, but i was looking at a car in my rear view and lost track of what the motor was doing. not trying to burn up my engine, so i wont be doing that again.
5-speed rules.

[AccordB20A]

lol i did the same thing in a 5 speed with my a20a2..trying to pass some idiot that wasnt letting me pass i ended up in 2nd gear doing 100km/h with like 7500rpms for quite some time before i realised i shd change to 3rd

[MessyHonda]

yeah, that'd probably be good. with my header and exhaust it has been able to keep power much past the red line. i was going to buy an MSD ignition box someone was trying to sell me but i'd rather buy one new. they arent that expensive but right now i dont have the money to blow on that kind of part. and i'm wanting to install a performance cam and do some head work. so yeah, would be a great idea to get a box with a rev limiter.



yeah i was thinking of getting a MSD box also. they are nice....i would get it brand new since they are around 150-180 new. and they have the built in rev limiter that you can tune depending on what chip you install on it.

[2oodoor]

could that much venturi vacuum from such a high rpm pop or dislodge an O ring? its started to clear up quite a bit and isnt dumping fuel. when i had replaced the O ring on the primary venturi, it quit doing it this crap last time. also, i was wondering if added ethanol would deteriorate my carb's O ring quickly? just a though, but i dunno if the fuel i use is made with more than before the staitions switched to the new brand of gasoline.
I don't see that happening on a regular basis, but you may be on to something with the ethanol additives. There are supposed to be limitations to how much can be added to regular unleaded fuel. Sometimes this kind of stuff is added to let water mix with gas, alcohol based additives.
I would not run like E85 in anything but an E85 flex fuel car.
Some rubbers do not react well to Ethanol.

[ChaseR]

when you start to notice the speedometer is not moving as far over as the tachometer like it was before 5K rpm, it might be a good idea to shift if you want to go faster.
.

Well yeah, but my car doesnt even start moving until 5000rpm

[2oodoor]

Well yeah, but my car doesnt even start moving until 5000rpm
it's all good!

[88accordSF]

ok, well as my car doesnt have a rev limiter i have accidentally over revved the engine and it started acting up as it did before when it was revved too high. what it did was dump fuel from the carb's primary venturi and wouldnt idle for shit due to this. tried adjusting it, didnt help at all. drove it on the freeway doing about 80-90 mph on a streatch, drove it sort of hard, and that freed up the problem. any of y'all that know valve trains, maybe the valve spring lifed and settled abnormally? i'm going to have to check the clearance of the valves when the engine has sat over night i guess, but i was thinking the spring because it cleared up after what i like to call and "italian tune up". doesnt seem to have low compression, but i havent had a chance or the tool to check that either. any ideas will be of some help.

yes. over revving the motor can seriously damage your valvetrain. honda only designed the tolerances of that valvetrain to handle a certain amount of load, which is why red line area is just that... red line area (not a great place to be all the time). exceeding red line is an even harsher situation for damage on your motor.

spring cracks are often visible with close inspection and a flashlight, looking all the way around each spring coil... a small mirror can help you see the undersides of each coil, just beam the flashlight right onto the mirror and you'll be able to spot potential spring damage. just unbolt the valvecover and check it out thoroughly, take pictures if needed...

an italian tune up won't fix valvetrain problems. that kind of approach only generally works on transverse, flat mounted chevy-similar motors, where the rocker arms do not get lateral tension to stay in place... like the big bore motors i'm building now :)

http://img522.imageshack.us/img522/8066/110tz7.th.jpg (http://img522.imageshack.us/my.php?image=110tz7.jpg)
http://img522.imageshack.us/img522/6808/140ke8.th.jpg (http://img522.imageshack.us/my.php?image=140ke8.jpg)


doesnt seem to have low compression, but i havent had a chance or the tool to check that either

it would help if that were a definite conclusion! can't really guess on this one. if you live in a bay area, i would be glad to help you out if you need to drive by my garage




it happened without me really thinking about it as the tranny usually shifts by itself and i was looking in my rear view mirror.

that could be a problem :)

you may have not been thinking about it, as i often do myself on a regular daily basis, but it was your foot was the object pressing the pedal to the floor...

looking in your rear view mirror at wide-open-throttle (WOT) is another problem in and of itself looking straight ahead often helps in this situation :p

as a person with 3 scheduled court dates, i know this problem very well...

[HondaBoy]

^ corvair? i just got through working on one. haha. but yeah, watching the car behind you not be able to keep up is mesmerizing i guess. oh yeah, 1st gear goes way past 60 mph lol. but yeah, thats asking to shatter some gears and whatnot. i've seen that before on a chevy 3 speed auto. i live in south texas by the way. by your pix, doesnt look like you live near here.

[88accordSF]

^ corvair?

yep. got three Vair motors: two daily-driver complete ready to go and run (pictured above), and another 2 bore-out builds in process.

anyways, about the valvetrain damage... i just received a new A20a1 head from J&C Cylinder Head (located on the East Coast). it looks absolutely top quality in terms of a head build, and i only paid $279 total, which included shipping, a full graphite head gasket & extra rubber gaskets and seals for the motor top end, and also NO CORE RETURN NECESSARY. thats a sweet deal for us gearheads. i get to throw on a new head, and keep the old one to build up another a20a motor in the garage, while i drive the current motor for another 50k-100k miles... J&C does a full three-angle-grind, tear-down inspection, the whole 9 yards.

they advertise a lot of different Honda heads on ebay.