45 replies to this topic

[hotwheels]

I just got my new motor installed and ready for 1st start..i get it started and cylinder 1 and 2 arnt firing and they Are getting spark and gas, , so its running on 3 and 4 cylinders, besides that im more worried about the knock im hearing wen it is started coming from the back side of the block under the exhaust manifold on cylinder 3 and 4 side..??(could it be a lifter or cam wearing in?? idk??) all my valve clearance are set to spec as i was told by the company i bought it from (valve rocker 0.016 spec on 1.5 minisport roller rockers, on 1275 A+ bored 40+. and im 85 % positive that the timing is dead on or atleast off a little bit, i have it at 12 degrees BTDC right now. i thought mayb it was 180 degrees off. so i tried it the other way to still nothing.

 

CARBS- im running used twin su hs4

compression test - 160 psi in all cylinders!!!

please gimme ur input!

 

heres a link of pics on my current project and the link of the motor i purchased

 

https://www.facebook...49597956&type=3 PICS

 

http://cgi.ebay.co.u...E:X:RTQ:GB:1123 ENGINE

 

 

i do have a clip of the sound 

 

 

thanks Derek

Edited by hotwheels, 01 September 2013 - 02:28 PM.

[sledgehammer]

I would check tappets 

 

then check compression

 

my first guess is head gasket

 

but it does sound more metallic 

 

are you getting oil to the head ?

[hotwheels]

thanks for the reply

 

my engine does not have the 2 tappet covers, its a solid block back there..that makes it tough cause not i cant see the lifters hmmm

my compression on all the cylinders were 160 psi on the dot.

 

i had it started with the valve cover off the other day and there is oil being pumped up to the head, i will do this again to see if there actually being pumped through all the holes.

 

and there is little signs of metal shavings i found on  the inside of the valve cover!?!?!

[Stevie W]

Hi,

1.5 ratio roller rockers can and do foul the rocker cover as I've found out!
Look at the rear inner face of your rocker box and the same on the rockers and see if there has been contact, especially the 2 outer rockers.
I had to take my Dremel to the rear face of the rocker box to gain clearance (tall alloy finned type rocker box, same as yours).
If your engine is only running on 2 cylinders, double check that fuel is getting to, and out of the carb connected to your non-firing cylinders.

Hope this helps,

Cheers, Steve.

Edited by Stevie W, 01 September 2013 - 06:38 PM.

[sledgehammer]

+1 on the rockers touching - can be made worse if the head has been skimmed , and no shims under rocker posts

 

to test whip rocker cover off - if still noisy - should be easier to find problem

 

also possible - but less noise - a push rod bent

 

with the compression's being good - as above with carb or air leak on 1&2 - or pipe off / split

 

check dash-pot pistons move freely - esp if stored for a while - they can stick messing up fueling

 

what engine vent are you running - just the timing cover ?

Edited by sledgehammer, 01 September 2013 - 07:36 PM.

[hotwheels]

Stewie W i have checked under my valve cover and there is no noticable wear marks to b found also still make noise when engine is running with valve cover off ;/ 

 

also cylinder 1 and 2 is firing now but kinda soflty if that makes sense, like it doesnt fire as good as 3 and 4 does.. hmmm

 

Sledgehammer i will check tomorrow for a bent push rod and also my twin carbs are used and hard to tune especially since the chokes keeps getting stuck open.. and are not in sync with each other

 

i think i want to ditch the twin hs4's to get just 1 su Hif6 1 3/4 carb, do you think the 1300 engine would run fine on just that???

 

also i made a make shift engine vent from my old engines back tappet vent cover, just a little bit of cutting and welding. i will install it tomorrow and have a picture of it.. also do i put a filter on the tip of the vent or do i run a hose somewhere?? mayb to the carb?? not really sure how that workss

 

but anyways thanks for the replys guys!! 

IM GETTING CLOSER!!!

[hotwheels]

also on my twin carbs, one carb has way more suction/ intake air flow than the other one, like a ton more and thats the one thats on cylinder 1 and 2 side!! but my intake manifold is wide oped to both carbs and both inlets to the engine so its all sharing?? i would think

[jaydee]

Twins need balancing, lots of infos about doing this on the web.

http://www.minimania...ype_Carburetors

 

Your engine is running way too rich, you'll bore wash it by running it this way. Correct it asap.

 

Also remove the rocker cover and run the engine a few secs without the cover, you'll easily see if the knocking is the rockers hitting on the cover.

[Cooperman]

Sounds like carb mis-match/balance is one problem and, possibly, the high-lift rockers are hitting the rocker cover as problem no.2.

Set static timing for initial start-up to 6 to 8 degrees BTDC, 12 degs is far too much advance and can cause 'pinking'. Once started adjust the ignition a bit to give optimum running. Balance the carbs accurately with a carb balancer or, if you don't have a balancer, a length of rubber hose in your ear and to each carb mouth until it 'sucks' with an identical hiss at 1200 rpm.

[hotwheels]

Sledgehammer i snapped a pic of my vent breather, where exactly do i connect the hose too?? carb?

 

Jaydee i was rained out today but hopefully tomorrow it will b dry and i can start it without the cover to verify the knocking, 

and yes my carbs are deff offf, i order that unisyn tool carb balancer today, and that will help me alot!!

 

Cooperman i will set my static timing back to 6-8 degrees BTDC tomorrow

 

thanks for your help guys!!

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Edited by hotwheels, 04 September 2013 - 12:49 AM.

[sledgehammer]

Sledgehammer i snapped a pic of my vent breather, where exactly do i connect the hose too?? carb? -

 

get someone on here to confirm this before connecting up vents - as I am unsure 

 

looking at the vid - you have two pipes blanked off , on the carb 

 

these go to a tee - then on to the vent you show in the pic (when fitted)

 

a pic here http://www.theminifo...in-hif38-carbs/

 

thanks to beaubrad

 

I don't know whether you should sync the carbs first thou 

Edited by sledgehammer, 04 September 2013 - 04:17 PM.

[hotwheels]

yes i really need to sync them but there kinda crappy but when that unisyn tool comes in ill give it a whirl!!!
and if that fails mayb 1 single HIF6

heres 2 vids with it runinng without the cover

[hotwheels]

also the pushrods are not bent

[Da11yn]

if you use a couple of foot of hose pipe with one end to the ear and move the other around the engine bay you should be able to pin point the knocking noise more accurately.

 

hard to tell from the a video but other options for knocking noises could be blowing exhaust manifold or fan hitting timing cover breather.

[sledgehammer]

 or fan hitting timing cover breather.

I'm sure it isn't - but in the first vid - look at the fan ?

 

when I first see it - I thought the fan was in time with the knock / strobing almost

 

does anyone else see that ?

 

may be an idea to slacken off the fan belt to eliminate it ?