5K Rebuild (Won'T Start)

[Zoidburg]

Hi guys,

 

I've been piecing my 5K back together and I'm now trying to start it (you may have read my earlier posts), but I'm not having any luck. The camshaft has been replaced with a brand new Genuine Toyota one, and I've installed hydraulic rocker gear (lifters, pushrods, rocker assembly). There's also a new 32/36 Weber on it.

 

I don't think it's the cam as the timing was thoroughly checked, and the carby/ignition seems to be working (as I got it to backfire!). The odd thing is whilst turning the motor over with the key in the ignition, it seems to be turning over too fast, like it has no compression. However when turning it over by hand, the motor feels tight.

 

Anyone have any ideas?

 

I have a hunch that maybe it's a rocker gear issue, perhaps the pushrods are the wrong length or the lifters are stuffed etc. I've not used this rocker gear before, so it's possible. If the valves are being kept open somehow, that would result in a lack of compression right?

 

Please any suggestions will be helpful, I need to get this sorted!

 

Thanks.

Edited December 12, 2010 by Zoidburg

[TheNOBBLER[RL]]

If your getting backfires through the carb re set your timing making sure the dizzy is not 180deg out. I did the same thing over the weekend, very easy to do. Spun it round 180 and fired straight up.

 

If this doesn't fix it then look into something darker and more upsetting!

 

JP

[Felix]

Maybe compression test it. Also crank it over with a timing light attached.

[philbey]

Definitely compression test it. Have you checked the lifter preload and all that Jazz?

 

Check your dizzy, you only need to be a couple of teeth out and it could be no go. Just because it backfired doesn't mean it's in the right spot. I once wired my dizzy on my 911 as 1-6-5-4-3-2 instead of 1-2-3-4-5-6 and it started up and ran, it just wouldn't rev nicely!!

[Zoidburg]

Food for thought...

 

Because it turns over so damn quickly, I still think the valves are not closing properly. According to the Toyota parts line there are three different types of 5K pushrod, and two different types of lifter for the hydraulic rocker gear. I reckon I have a mismatch.

 

:hmm:

[ROLLA FOR L1FE]

Food for thought...

 

Because it turns over so damn quickly, I still think the valves are not closing properly. According to the Toyota parts line there are three different types of 5K pushrod, and two different types of lifter for the hydraulic rocker gear. I reckon I have a mismatch.

 

:hmm:

Do you have another set of rocker gear that you can try? and pushrods?

Edited December 13, 2010 by ROLLA FOR L1FE

[Zoidburg]

Unfortunately no, only got the one set.

 

The rocker assemblies are the same, so I may only need different length pushrods and the other lifters. However it should still start regardless.

 

I'm thinking maybe the dizzy is 180 degrees out. Also noticed today that the mixture screw on my carby was seated, so it would'nt have got any fuel... which can't help!

 

Will try again tomorrow :glare:

[ROLLA FOR L1FE]

Unfortunately no, only got the one set.

 

The rocker assemblies are the same, so I may only need different length pushrods and the other lifters. However it should still start regardless.

 

I'm thinking maybe the dizzy is 180 degrees out. Also noticed today that the mixture screw on my carby was seated, so it would'nt have got any fuel... which can't help!

 

Will try again tomorrow :glare:

 

you can get 2 sizes of rocker gear. one being taller then the other.

[philbey]

Like I said, did you check your lifter preload? Because this will identify problems like you mentioned. Do a compression check.

[snot35]

I've got a 5K in bits at the moment. I might be prepared to lend rocker bits so that you can work out the problem if you like? It's a D dish motor and I'm pretty sure mine are the shortest push rods (150mm?). PM and we can talk it through :)

Edited December 13, 2010 by snot35

[GJM85]

I've got a 5K in bits at the moment. I might be prepared to lend rocker bits so that you can work out the problem if you like? It's a D dish motor and I'm pretty sure mine are the shortest push rods (150mm?). PM and we can talk it through :)

 

Sounds like the gear he needs. I supplied the pushrods(156mm), lifters and rockers he's using and they came out of my shallow dished 5k. I do believe there is a 6mm difference in head height due to the different size compression chambers between the D dish head and the O dish head. This would be the resulting 6mm difference in pushrod length.

[Zoidburg]

More than likely I need the other lifters and pushrods, makes perfect sense.

 

If anyone can help with this please PM me!

[CaptainL]

the problem is easy!!!its the timing! turn your engine at the zero spot!it has a small edge

 

http://img375.imageshack.us/img375/4016/timingo.jpg

 

then ckeck the cables that is at correct place!! the correct is this!

 

http://img694.imageshack.us/img694/5346/casket.jpg

 

then check the dizzy to point at the number one at the head of the dizzy cap!!if they don't just make it to point!!!! :blush:

 

"ALL OF THESE MAKE SENSE IF U don't MESS IT UP WITH THE CAM....."

:hmm:

Do it and tell us!!!

[Zoidburg]

Thanks for the timing tips!

 

I'm going to track down the correct length pushrods, then try again. If it still does'nt work, then I'll mess with the timing. I now know for certain I have the wrong pushrods, so I'm going to start by fixing that and then take it from there.

 

I'll let you all know if the situation improves!

 

Cheers guys.

[altezzaclub]

What about all the bent valves from the 'too-long' pushrods??? :hmm:

 

Actually, you should be able to watch the valves open & close by taking off the tappet cover and turning the motor by hand. I think if you gently lever a rocker up with a screwdriver above a shut valve you will get a tappet gap, but that's from Armstrong Siddeley experience! :laff: