PINTO PROBLEM? (OR NOT?)

[richies2.0gl]

I have just assembled my fast road Pinto, 205 block, decked, balanced, new pistons, rings, bearings, oil pump, skimmed head, FR32 Cam, vernier pulley, 38DGAS Carb, flowed head and 4 branch manifold.

The engine really runs sweet with more than enough beans! But when you remove the oil filler cap when its running, I expect a slight blow when placing my hand over the hole, however this engine sucks? When I make a seal on the filler cap hole with my hand, it sucks and can feel a vacuum when my hand is removed.

Is this right? I have never had an engine do this before. The oil pressure is fine.

I would appreciate your help as there is a significant amount of my hard earned in this engine.

Richie

[anonymous-user]

Do you have a PCV installed in the pipe between the inlet manifold and the crankcase??

[richies2.0gl]

Yes, I do, I gave it a visual check and cleaned it out before I put it on the engine.

[oakdale]

richies2.0gl said:

I have just assembled my fast road Pinto, 205 block, decked, balanced, new pistons, rings, bearings, oil pump, skimmed head, FR32 Cam, vernier pulley, 38DGAS Carb, flowed head and 4 branch manifold.

The engine really runs sweet with more than enough beans! But when you remove the oil filler cap when its running, I expect a slight blow when placing my hand over the hole, however this engine sucks? When I make a seal on the filler cap hole with my hand, it sucks and can feel a vacuum when my hand is removed.

Is this right? I have never had an engine do this before. The oil pressure is fine.

I would appreciate your help as there is a significant amount of my hard earned in this engine.

Richie

This is normal, the pcv valve allows the inlet manifold to draw air/fumes from the crankcase which will cause a vacuum when you hold your hand over the filler hole(the filler cap has air bleed holes).

[richies2.0gl]

Well, that is good news! Thank you Oakdale.

[oakdale]

I have quite a bit of experience of running these engines on DGAS carbs, They work well with a cam like yours and produce good power, but can give a mid range flat spot (rich) due to the carb being designed for a v6.

If you need any advice on set up, pm me.

[Pumaracing]

If I recall correctly the problem with the 3 litre DGAS on a 2 litre is the power enrichment valve which swamps the smaller engine with fuel and needs disabling before the jetting can be set up on a dyno. Other than that it's a perfectly decent carb.

[richies2.0gl]

I am aware of some issues with the DGAS on the Pinto. I decided to go down the more expensive route and bought a new carb already jetted and set up for a 2 litre with a manual choke conversion as the auto choke isnt really that good to be fair.

[TonyRPH]

Many moons ago I had a 38 DGAS on a 1.6 Kent engine with a mild cam.

It took some fiddling with different emulsion tubes to get clean acceleration through the rev range.

Fortunately I had a massive box of bits with which to substitute from.

I seem to recall that I put a stronger spring on the power valve to reduce the amount of fuel delivered on sudden acceleration. Can't remember if I tweaked the (accelerator) pump though.

In any case - once I got it optimised, the performance was quite a bit better than the 36DCD7 it replaced.

Not long after though, I swapped the 38DGAS for a pair of twin 40's