• Advertisement

Technical question.

Use this forum to discuss small engines, and the equipment or machinery that they power. This is the main section for any technical help posts and related questions.

Technical question.

Postby KE4AVB » Tue Jan 29, 2019 11:41 am

Does the Briggs 790562 camshaft use ramp or bump compression? I know it doesn't have a mechanical ACR on it.
User avatar
KE4AVB
Forum Pro
 
Posts: 3907
Joined: Mon Nov 04, 2013 11:23 am
Location: TorLand

Advertisement

Re: Technical question.

Postby hanz63 » Tue Jan 29, 2019 5:08 pm

You won't find the same bump that you would on a single w/ the arm. It was explained to me that any type of a compression release in these cams was more in grind- so in the timing and duration. By these standards, is it actually a compression release. Kohler's late twins reference an ACR this way. My only issue with one of these Intek twin cams has been wear.
hanz63
Guide
 
Posts: 152
Joined: Thu May 26, 2016 3:07 am

Re: Technical question.

Postby KE4AVB » Tue Jan 29, 2019 6:00 pm

Then it is what I am referring to then as ramp or bump as these are a grind profile on the cam lobes. Now all I got to figure if it is on the intake or exhaust lobes.
User avatar
KE4AVB
Forum Pro
 
Posts: 3907
Joined: Mon Nov 04, 2013 11:23 am
Location: TorLand

Re: Technical question.

Postby RoyM » Tue Jan 29, 2019 8:39 pm

Being used in an ohv twin it will be on the exhaust. What are you trying to do?
Briggs and Stratton MST
RoyM
Forum Pro
 
Posts: 466
Joined: Tue Nov 05, 2013 2:38 pm
Location: Okanagan valley British Columbia

Re: Technical question.

Postby KE4AVB » Tue Jan 29, 2019 11:38 pm

It depends on the head design of the 406777-0138-E1. I have seen it on both intake and exhaust depending engine design and OEM The IPL is a little confusing on this engine it shows the intake low but also have the exhaust valve spring low. It would be easier to know if the engine was in front of me but it is a little to far away for me to go see but with this polar vortex it sure would be nice if I could go although my friend is in the middle of a heatwave plus the 18 hrs one way on a plane would be rough on my back.

Just trying to understand why the 20 hp needs the larger 4-3/8" industrial starter but it would explain why it need the increase torque if the ACR isn't there. Just helping out an Aussie friend.
User avatar
KE4AVB
Forum Pro
 
Posts: 3907
Joined: Mon Nov 04, 2013 11:23 am
Location: TorLand

Re: Technical question.

Postby hanz63 » Wed Jan 30, 2019 5:08 pm

So he has a hard cranking condition? I assume he's compared valve lift, insured the rockers are tight, guides in place and the lash set up. He could even try .003 / .005 though I set them at 4 /6 which is probably right by the book - depending WHAT book. Personally, I rarely replace a starter on these. You'd think that they would be easier to crank than a one banger by design.
hanz63
Guide
 
Posts: 152
Joined: Thu May 26, 2016 3:07 am

Re: Technical question.

Postby KE4AVB » Wed Jan 30, 2019 5:49 pm

Nope. Governor and starter clutch assembly failure. The local shop over there was saying the governor failure was cause by the ACR self destructing. The starter failure was just a normal gear failure but he lost the circlip and spring; therefore, he was thinking just installing a new starter and was wonder if smaller starter would work. I got him to install a new starter clutch kit but he still got to open the crankcase and check the governor assy.

I was just wanting to my head straight about the camshaft since I no mechanical ACR on it. Maybe I just order one as I probably need one anyway. I do keep a couple of the 793880 in stock all the time.
User avatar
KE4AVB
Forum Pro
 
Posts: 3907
Joined: Mon Nov 04, 2013 11:23 am
Location: TorLand

Re: Technical question.

Postby hanz63 » Thu Jan 31, 2019 1:20 am

Hopefully he does his due diligence and verifies that it is an internal issue first. True, on a single- that little arm can do a lot of damage. On a twin, hopefully not a funky stem. Other than for the very occasional worn lobe, the only time I even see a cam on these is during the joy of sump gasket replacement.
hanz63
Guide
 
Posts: 152
Joined: Thu May 26, 2016 3:07 am

Re: Technical question.

Postby KE4AVB » Thu Jan 31, 2019 11:59 am

Most of the worn twin cams I find here are on valve adjustments on OHV engines. I have ad to replace several due to very little lift.

As the Aussie I just waiting to hear what he finds now.
User avatar
KE4AVB
Forum Pro
 
Posts: 3907
Joined: Mon Nov 04, 2013 11:23 am
Location: TorLand

Re: Technical question.

Postby KE4AVB » Sat Feb 02, 2019 11:13 am

Well received back images of the inside. The governor mounting stud which is pressed into the crankcase below #1 cylinder came out. Due to his date code the bad news is that it is NLA and he needs a new engine.
User avatar
KE4AVB
Forum Pro
 
Posts: 3907
Joined: Mon Nov 04, 2013 11:23 am
Location: TorLand

Next

Return to Technical Discussion Forum

Who is online

Users browsing this forum: No registered users and 8 guests

cron