Rotaryman88

Lol, ok...this is something has bothered me for some time now. Just about every new engine I've seen or heard of somebody installing you almost always have to roll start it to get it to fire up the first time(as a last resort)..but then the car starts by cranking every time after that...why the hell does that work!? It has never made sense to me..

like my rebuild will crank and start but then die and wont restart..I haven't tried pull starting it as I am in the middle of other mods prohibiting from the motor running for now...i think I'm gonna push start it next.



Just wondered what you all's theories are on the pull starting...

1Revvin7

Doesn't have enough compression to start itself maybe?

BigTurbo74

i was told that the starter doesn't crank the engine at a high enough speed to get a good spark or momentum going. compression does have something to do with it as well. once i had my car driving around for a while i now am able to start it with the key and starter. i think it just needs to break in to start going back to normal....

chase78

NO guys a good engine rebuilder will tell 19 out of 20 a rebuild engine should start normally. and that 1 out of 20 is because they forgot to plug the battery back in.

IF you have problem starting her up and you installed everything right

then its the engine. Low compression, no compression, or whatever it may be its still boils down to a bad rebuild.

All you need to fire, fuel , and compression and then everything else is to make it run a little prettier.

pengaru

A rebuild with reused housings and/or seals wil not be making very good compression initially, hence the break-in period. If a engine starts and runs fine with the help of a push start it very clearly proves that either a: the start is not cranking well enough and needs to be replaced or b: the engine simply does not have good compression yet which will improve as the break-in progresses. A engine with low compression (common with rebuilds reusing parts) will have difficulty starting at low rpm cranking but at higher rpm the poor sealing of the currently poorly mating seals becomes less of an issue due to the less time available for the air/fuel to leak past the seals.



It does not necessarily mean blown / bad / broken engine, it's basically to be expected when you reuse rotor housings and apex seals. Why do you think you run them in for xxx miles under 4000 rpm and they will generally have better compression after this run-in period.



My point is, the requirement for cranking faster than the starter can does not prove anything. The engine may still be bad, or it might be perfectly fine, it's inconclusive. Especially when after the first time you do this, the engine is perfectly capable of cranking and starting normally without a push start, the situation has already improved drastically.

BigTurbo74

thank you peng, and that is exactly the situation i'm in, at first i had to push start, but now it starts with a couple cranks of the starter.... rebuild a motor with used everything except for oil rings side seals and apex seals and see if you get the same results as i do.

Rotaryman88

Yea, i'm goin w/ peng on this one....



My theory is this..i have an Atkins motor, which i know atkins reuses a lot of housings and such, but it is supposed to have new seals, etc...



I've used them in the past and had motors crank right up...but mine may be a little weaker...so once everything is good to go, i'll just roll start it...



my thing is..mine has cranked and started, but doesnt run right unless i keep my foot on it...so i'm not sure if push starting is gonna really help much..

1Revvin7