P700 Camshaft replacement help

[HondaTech]

Thanks for that.

Actually most cars are OHC and don't have lifters at all, if you want to be technical about it

 

[Chuckt14]

Your on overlap, spin it 360 degrees and line the "T "mark up again. The line will be at the bottom then and it will be at TDC.

When your putting the machine back together, you can just put the new camshaft in with the line at the bottom and it will be fine. The engine doesn't care what "tdc" position the crank is in as long as the timing marks line up.

Say I put it back together same way as in pic, would that be alright?
Also say I adjusted the valves in this same position, would that be alright or no

 

[HondaTech]

Say I put it back together same way as in pic, would that be alright?
Also say I adjusted the valves in this same position, would that be alright or no

It's going to be very difficult to assemble everything, since the cam will be trying to hold the valves opened.

The 700 engine has the rockers in the head cover and the entire top end has to be torqued down with the head cover installed. You would be pushing the valves open while installing the head cover and may damaged the cylinder studs or valve train.

Not only that but since the valves are open, the valve clearance will appear very tight and adjusting them in that position will make them very loose and noisy since they should've been adjusted when closed on the base circle.

Just leave the crank on the "T" mark and install the camshaft in the proper orientation with the line on the bottom, then adjust the valves with everything torqued properly.

 

[Chuckt14]

It's going to be very difficult to assemble everything, since the cam will be trying to hold the valves opened.

The 700 engine has the rockers in the head cover and the entire top end has to be torqued down with the head cover installed. You would be pushing the valves open while installing the head cover and may damaged the cylinder studs or valve train.

Not only that but since the valves are open, the valve clearance will appear very tight and adjusting them in that position will make them very loose and noisy since they should've been adjusted when closed on the base circle.

Just leave the crank on the "T" mark and install the camshaft in the proper orientation with the line on the bottom, then adjust the valves with everything torqued properly.

How do you know overlap vs tdc

 

[Chuckt14]

It's going to be very difficult to assemble everything, since the cam will be trying to hold the valves opened.

The 700 engine has the rockers in the head cover and the entire top end has to be torqued down with the head cover installed. You would be pushing the valves open while installing the head cover and may damaged the cylinder studs or valve train.

Not only that but since the valves are open, the valve clearance will appear very tight and adjusting them in that position will make them very loose and noisy since they should've been adjusted when closed on the base circle.

Just leave the crank on the "T" mark and install the camshaft in the proper orientation with the line on the bottom, then adjust the valves with everything torqued properly.

Also torque spec is 48 ft lbs on the 4 nuts on top the valve cover?

 

[HondaTech]

How do you know overlap vs tdc

On overlap the rocker arms will be tight and not move

On TDC compression the rocker arms will be loose and allow for valve clearance inspection.

If the crank is on the "T" mark, it doesn't care whether the cam is on overlap or TDC. You can't put a single cylinder engine 180degrees out of time. Setting the cam on TDC will time it and allow for engine assembly and valve clearance inspection.

I'm not sure what the torque is on the stud nuts

 

[Muggster71]

check your other topic on this - post #8, an ingenious owner flushed his engine with gas, diesel, etc…… - didn’t split cases

Yeah, i saw that and did a little research and decided against it. One thing I’ve wondered is….wtf is the oil filter for if the screens get clogged up?

 

[Chuckt14]

On overlap the rocker arms will be tight and not move

On TDC compression the rocker arms will be loose and allow for valve clearance inspection.

If the crank is on the "T" mark, it doesn't care whether the cam is on overlap or TDC. You can't put a single cylinder engine 180degrees out of time. Setting the cam on TDC will time it and allow for engine assembly and valve clearance inspection.

I'm not sure what the torque is on the stud nuts

Got it figured it out, runs great now thanks for your help

 

[Remington]

Got it figured it out, runs great now thanks for your help

Glad we could help. Thays whats so good about this site.

Now dont forget to do an Intro thread and post up pics of your rig of before or after your issue

 

[Muggster71]

Picked up a 700-4 recently
Had the flat cam lobe symptoms, set engine to tdc, pulled apart and found the camshaft like this.
is camshaft 180° off?
I know the larger line should be parallel with the casing

View attachment 408028

Hello, was wondering which parts you replaced? Just cam and followers?

 

[Muggster71]

Thanks for the feedback, Chuck.

 

[Muggster71]

Ok, so I replaced camshaft, the intake lobe were pretty worn out, exhaust not so much. I put new buckets and gaskets also. Put the molybdenum grease stuff on cams but forgot to put oil on new camshaft bearings. Does anyone think that will be an issue? Or will they get plenty when I start it up? Also, would it be a good idea to fill tub up with oil that camshaft is in? I also realized that I had been running 10w40 instead of 10w30. Would that cause any of these cam issues? Thanks for any advice. At this point I just have the head reassembled but not torqued down so it wouldn’t be a big deal if I needed to take it apart, I don’t think anyway. Would that mess up the gaskets?

 

[DRZRon1]

Ok, so I replaced camshaft, the intake lobe were pretty worn out, exhaust not so much. I put new buckets and gaskets also. Put the molybdenum grease stuff on cams but forgot to put oil on new camshaft bearings. Does anyone think that will be an issue? Or will they get plenty when I start it up? Also, would it be a good idea to fill tub up with oil that camshaft is in? I also realized that I had been running 10w40 instead of 10w30. Would that cause any of these cam issues? Thanks for any advice. At this point I just have the head reassembled but not torqued down so it wouldn’t be a big deal if I needed to take it apart, I don’t think anyway. Would that mess up the gaskets?

iMO, I’d want lube on new or used bearings - it takes a couple of seconds to build oil pressure

not sure about gaskets but I’d never re-use for the time it takes to pull apart and replace

Oil viscosity - who cares 30/40 - it’s fine

 

[Muggster71]

iMO, I’d want lube on new or used bearings - it takes a couple of seconds to build oil pressure

not sure about gaskets but I’d never re-use for the time it takes to pull apart and replace

Oil viscosity - who cares 30/40 - it’s fine

Well, I just put new gaskets on it but haven’t torqued the cap nuts yet or started it yet so I’m thinking the gaskets would be ok? Some reason why you don’t think so? It was a hundred plus dollars for those things.

 

[Muggster71]

Ok, so I got it all put back together and it’s running great, lots of pep, top speed of 40 instead of 20. Thanks to everyone that helped me👍

 

[Muggster71]

Here is a couple of pics. The intake cam was worn pretty badly, the lifter bucket was in pretty rough shape also. I don’t think improper hardening is the problem here because the exhaust cam was in relatively good shape. Seems like if it was a hardening issue, both cams would be equally worn. I am assuming the lifter buckets are hardened to an equal degree also so it seems to me that excuse is bunk.

 

[DG Rider]

Here is a couple of pics. The intake cam was worn pretty badly, the lifter bucket was in pretty rough shape also. I don’t think improper hardening is the problem here because the exhaust cam was in relatively good shape. Seems like if it was a hardening issue, both cams would be equally worn. I am assuming the lifter buckets are hardened to an equal degree also so it seems to me that excuse is bunk.

View attachment 409457 View attachment 409458 View attachment 409459 View attachment 409460 View attachment 409461

There's been lots of speculation as to why, but nothing definitive. Seems to affect machines that idle a lot the most. @HondaTech is there any oil feed to this area except splash from the top end? I wonder if prolonged idling just doesn't provide enough oil?

 

[Muggster71]

There's been lots of speculation as to why, but nothing definitive. Seems to affect machines that idle a lot the most. @HondaTech is there any oil feed to this area except splash from the top end? I wonder if prolonged idling just doesn't provide enough oil?

When I took the head off, the tray that the cam sits in was full of oil, fwiw. I filled it back up during reassembly. Mine has a little over 570 hours/2000miles on it. I start and stop the engine usually 4 times a day, minimum. It doesn’t normally sit and idle so….who knows?

 

[DG Rider]

...so….who knows?

Honda. But they won't say.

 

[Muggster71]

Honda. But they won't say.

https://hondasxs.com/attachments/img_3232-jpeg.409460/

It occurred to me that maybe the cams are not the issue and it’s actually the cam followers? The followers would be dry every time you started the machine, especially on cold starts, being that their faces are pointed downward, letting the oil drain from the surface. There is a lot I still don’t know and am merely speculating. Maybe putting the machine in gear and rocking it a bit before a cold start would lube everything up a bit before you started it being that the cam shaft sits in a little tub of oil. The thing that puzzles me the most is, why is it the intake cam lobe that goes first?