2.25 Mystery

[utahseries]

This one is a head scratcher for everyone. A freshly rebuilt 2.25 that pushes air out of the carb instead of sucking it in? The fuel is nicely atomized though, it just is coming out of the carb instead of into the cylinders :D Any ideas?

[stomper]

I'm way out of my league here, and so I should probably just wait and listen to what others suggest. But it almost sounds like the valves are 180 degrees out of sync. So the intake valves are open when they should be closed. I don't even know if is possible for that to occur though.:confused:

[mongoswede]

I'm way out of my league here, and so I should probably just wait and listen to what others suggest. But it almost sounds like the valves are 180 degrees out of sync. So the intake valves are open when they should be closed. I don't even know if is possible for that to occur though.:confused:


This is very possible to occur and could quite possibly be the issue especially if its a freshly reassembled engine. The reason being that the cam has been installed on TDCE (Top Dead Center Exhaust) instead of TDCF (Top Dead Center Firing). Easy enough to do...or I should say that the cam is probably OK but the timing chain is out of sync by 180 degrees. Luckily these are not interference engines (where valves hit pistons when things are misaligned).

[artpeck]

Not having messed with this part of my series engine I had the same issue long ago on a porsche and it was the timing chain which was off by a half rotation or 180 degrees. Logic would say this is just about the only way this could happen. You can also see of the exhaust is sucking in as that would be the corollary of the carb issue.

[artpeck]

Luckily these are not interference engines (where valves hit pistons when things are misaligned).[/QUOTE]

Unfortunately in a porsche engine this was not the case...:-(

[Nium]

The intake manifold is attached to the exhaust ports and the exhaust manifold is attached to the intake? No, just kidding I have no idea. Those that know more than I seem to have it. My only guess would be the intake valves are remaining open, but I've never troubleshot this issue so I'm very interested in the solution.

[LR Max]

Cam ain't installed right.

Set to TDC and see if your #1 piston is up or down. If its down, then pull the timing chain cover.

[Terrys]

Cam ain't installed right.

Set to TDC and see if your #1 piston is up or down. If its down, then pull the timing chain cover.
The original question isn't a head scratcher, but this comment sure is. The timing mark on front pulley, or flywheel, says where the piston is, not the cam, so how could it say you're on TDC and the #1 piston be anywhere but at the Top?
There must be alot of this going around. There was some kid at Clifton's meet back in November who had the same issue. I told him the same thing and he looked like he didn't think old people can be trusted.

[kevin-ct]

You don't say if this is the first time the engine is being started after the re build?

Who built the engine? from what you said, sounds like the camshaft is off it's mark.

[I Leak Oil]

Cam and crank are out of phase. Remove the front cover and timing chain. Reclock cam and crank and reinstall the chain per the manual. Let's hope it's that easy because otherwise you need to check to see if your valves are stuck open!

[Nium]

There must be alot of this going around. There was some kid at Clifton's meet back in November who had the same issue. I told him the same thing and he looked like he didn't think old people can be trusted.

Perhaps its not the mechanical accuracy of your advice that puts people off but the way it's presented. Just because someone may come across as not knowing what their talking about doesn't mean they will appreciate accurate mechanical advice delivered in a condescending tone. Ignorance is defined as being uninformed or having a lack of knowledge and shouldn't be mistaken for a lack of intelligence or the ability to understand. Just a thought take it or leave it.

Cheers!

[utahseries]

That makes sense. My uncle who was trained by the Land Rover school in the 1970's was the one who rebuilt the motor. But hey, I guess everyone makes mistakes no matter what their experience!

[Apis Mellifera]

I think everyone has overlooked the first (and easiest) step. Check your valve lash. It is possible that the rebuilder just bolted down the rocker assembly without checking lash. This could prevent the inlet valves from fully closing. After checking lash, proceed to pulling the timing cover and check that things line up when #1 is TDC.

[mongoswede]

I think everyone has overlooked the first (and easiest) step. Check your valve lash. It is possible that the rebuilder just bolted down the rocker assembly without checking lash. This could prevent the inlet valves from fully closing. After checking lash, proceed to pulling the timing cover and check that things line up when #1 is TDC.

Well technically the first step I learned in tech school was check your fuses :D

[Terrys]

Perhaps its not the mechanical accuracy of your advice that puts people off but the way it's presented. Just because someone may come across as not knowing what their talking about doesn't mean they will appreciate accurate mechanical advice delivered in a condescending tone. Ignorance is defined as being uninformed or having a lack of knowledge and shouldn't be mistaken for a lack of intelligence or the ability to understand. Just a thought take it or leave it.

Cheers!

I guess I ruffled your feathers when I asked how your 'bad low tension lead' diagnosis could be rectified by pulling the choke out. I humbly apologize to you, but it seemed alot of people missed RoverForms full post, and his hint to carb issues when he said his engine ran without wanting to die when he pulled the choke out. If you're refering to my comment that the guy I advised his cam was out of time with his crank, I can assure you I didn't tell him my thoughts in a condescending manner. We were in a group of guys talking about his problem, and being older by 2x+ than the group I didn't butt in until they asked me what I thought. Or, I spose you could be refering to my reflection that the piston would have to be up if he was on TDC. I dunno, I can't presume I know anyone's level of automotive intelligence, so I don't. I can assume that the understand enough if they're even bothering to come on the forum and ask. I will keep your thoughts in mind when I respond, but I can't promise I learned anything from Emily Post, least of all, motor mechanics.